UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d)

of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 2, 2023

MAGENTA THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (857) 242-0170

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company  ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐

Merger Agreement

On May 2, 2023, Magenta Therapeutics, Inc., a Delaware corporation (“Magenta”), Dio Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Magenta (“Merger Sub”), and Dianthus Therapeutics, Inc., a Delaware corporation (“Dianthus”), entered into an Agreement and Plan of Merger (the “Merger Agreement”), pursuant to which, among other matters, and subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement, Merger Sub will merge with and into Dianthus, with Dianthus continuing as a wholly owned subsidiary of Magenta and the surviving corporation of the merger (the “Merger”). The Merger is intended to qualify for federal income tax purposes as a tax-free reorganization under the provisions of Section 368(a) of the Internal Revenue Code of 1986, as amended.

Subject to the terms and conditions of the Merger Agreement, at the closing of the Merger, (a) each then-outstanding share of Dianthus common stock (including shares of Dianthus common stock issued upon conversion of Dianthus preferred stock and shares of Dianthus common stock issued in the financing transaction described below) will be converted into the right to receive a number of shares of Magenta common stock calculated in accordance with the Merger Agreement (the “Exchange Ratio”), (b) each then-outstanding option to purchase Dianthus common stock will be assumed by Magenta, subject to adjustment as set forth in the Merger Agreement and (c) each then-outstanding warrant to purchase shares of Dianthus common stock will be converted into a warrant to purchase shares of Magenta common stock, subject to adjustment as set forth in the Merger Agreement. Under the terms of the Merger Agreement, prior to the closing of the transaction, the board of directors of Magenta (the “Board”) will take actions to (i) accelerate the vesting of equity awards of Magenta and (ii) extend the expiration time of Magenta options with an exercise price of $2.00 or less, in each case, in accordance with the terms of the Merger Agreement.

Under the Exchange Ratio formula in the Merger Agreement, upon the closing of the Merger, on a pro forma basis and based upon the number of shares of Magenta common stock expected to be issued in the Merger, pre-Merger Dianthus stockholders (including Dianthus stockholders issued shares of Dianthus common stock and pre-funded warrants in the financing transaction described below) will own approximately 78.7% of the combined company and pre-Merger Magenta stockholders will own approximately 21.3% of the combined company. For purposes of calculating the Exchange Ratio, (i) shares of Magenta common stock underlying Magenta stock options with an exercise price per share of less than or equal to $0.778 (as adjusted for any reverse stock split), warrants and other rights to receive shares outstanding as of immediately prior to the closing of the Merger will be deemed to be outstanding, (ii) shares of Magenta common stock issuable upon the settlement of Magenta restricted stock units (excluding performance-based restricted stock units for which the performance condition has not been met) will be deemed to be outstanding and (iii) all shares of Dianthus common stock underlying outstanding Dianthus stock options, warrants and other derivative securities will be deemed to be outstanding. The Exchange Ratio will be adjusted to the extent that Magenta’s net cash at closing is less than $59.5 million or greater than $60.5 million and based on the amount of the financing transaction described below, as further described in the Merger Agreement.

In connection with the Merger, Magenta will seek the approval of its stockholders to, among other things, (a) issue shares of Magenta common stock issuable in connection with the Merger under the rules of The Nasdaq Stock Market LLC (“Nasdaq”) and (b) if deemed necessary by Magenta, Dianthus and Merger Sub, amend its amended and restated certificate of incorporation to effect a reverse stock split of Magenta common stock (the “Magenta Voting Proposals”).

Each of Magenta and Dianthus has agreed to customary representations, warranties and covenants in the Merger Agreement, including, among others, covenants relating to (1) using commercially reasonable efforts to obtain the requisite approval of its stockholders, (2) non-solicitation of alternative acquisition proposals, (3) the conduct of their respective businesses during the period between the date of signing the Merger Agreement and the closing of the Merger, (4) Magenta using commercially reasonable efforts to maintain the existing listing of the Magenta common stock on Nasdaq and cause the shares of Magenta common stock to be issued in connection with the Merger to be approved for listing on Nasdaq prior to the closing of the Merger and (5) Magenta filing with the U.S. Securities and Exchange Commission (the “SEC”) and causing to become effective a registration statement to register the shares of Magenta common stock to be issued in connection with the Merger (the “Registration Statement”).

Consummation of the Merger is subject to certain closing conditions, including, among other things, (1) approval by Magenta stockholders of the Magenta Voting Proposals, (2) approval by the requisite Dianthus stockholders of the adoption and approval of the Merger Agreement and the transactions contemplated thereby, (3) Nasdaq’s approval of the listing of the shares of Magenta common stock to be issued in connection with the Merger and (4) the effectiveness of the Registration Statement. Each party’s obligation to consummate the Merger is also subject to other specified customary conditions, including regarding the accuracy of the representations and warranties of the other party, subject to the applicable materiality standard, and the performance in all material respects by the other party of its obligations under the Merger Agreement required to be performed on or prior to the date of the closing of the Merger.

The Merger Agreement contains certain termination rights of each of Magenta and Dianthus. Upon termination of the Merger Agreement under specified circumstances, Magenta may be required to pay Dianthus a termination fee of $13,300,000 and/or reimburse Dianthus’ expenses up to a maximum of $1,500,000, and Dianthus may be required to pay Magenta a termination fee of $13,300,000 and/or reimburse Magenta’s expenses up to a maximum of $1,500,000.

At the effective time of the Merger (the “Effective Time”), the Board is expected to consist of eight members, six of whom will be designated by Dianthus and two of whom will be designated by Magenta.

Financing Transaction

Concurrently with the execution and delivery of the Merger Agreement, certain parties have entered into subscription agreements with Dianthus, pursuant to which they have agreed, subject to the terms and conditions of such agreements, to purchase immediately prior to the consummation of the Merger shares of Dianthus common stock and pre-funded warrants for an aggregate purchase price of approximately $70 million. The consummation of the transactions contemplated by such agreements is conditioned on the satisfaction or waiver of the conditions set forth in the Merger Agreement and in the subscription agreement. Shares of Dianthus common stock and pre-funded warrants issued pursuant to this financing transaction will be converted into shares of Magenta common stock and warrants of Magenta in the Merger in accordance with the Exchange Ratio.

Contingent Value Rights Agreement

At or prior to the Effective Time, Magenta will enter into a Contingent Value Rights Agreement (the “CVR Agreement”) with a rights agent (“Rights Agent”) pursuant to which Magenta’s pre-Merger common stockholders will receive one contingent value right (each, a “CVR”) for each outstanding share of Magenta common stock held by such stockholder on such date. Each CVR will represent the contractual right to receive certain net proceeds, if any, derived from any consideration that is paid to Magenta as a result of the disposition of Magenta’s pre-Merger legacy assets by December 31, 2023, net of any indemnity obligations, transaction costs and certain other expenses, during the period that is three years after the closing of the Merger.

The contingent payments under the CVR Agreement, if they become payable, will become payable to the Rights Agent for subsequent distribution to the holders of the CVRs. In the event that no such proceeds are received, holders of the CVRs will not receive any payment pursuant to the CVR Agreement. There can be no assurance that any holders of CVRs will receive any payments with respect thereto.

The right to the contingent payments contemplated by the CVR Agreement is a contractual right only and will not be transferable, except in the limited circumstances specified in the CVR Agreement. The CVRs will not be evidenced by a certificate or any other instrument and will not be registered with the SEC. The CVRs will not have any voting or dividend rights and will not represent any equity or ownership interest in Magenta or any of its affiliates. No interest will accrue on any amounts payable in respect of the CVRs.

Support Agreements and Lock-Up Agreements

Concurrently with the execution of the Merger Agreement, (i) certain stockholders of Dianthus (solely in their respective capacities as Dianthus stockholders) holding approximately 65.7% of the outstanding shares of Dianthus capital stock have entered into support agreements with Magenta and Dianthus to vote all of their shares of Dianthus capital stock in favor of the adoption and approval of the Merger Agreement and the transactions contemplated thereby and against any alternative acquisition proposals (the “Dianthus Support Agreements”) and (ii) certain stockholders of Magenta holding approximately 6.9% of the outstanding shares of Magenta common stock have entered into support agreements with Magenta and Dianthus to vote all of their shares of Magenta common stock in favor of the Magenta Voting Proposals and against any alternative acquisition proposals (the “Magenta Support Agreements,” and, together with the Dianthus Support Agreements, the “Support Agreements”).

Concurrently with the execution of the Merger Agreement, certain executive officers, directors and stockholders of Magenta and Dianthus have entered into lock-up agreements (the “Lock-Up Agreements”) pursuant to which, subject to specified exceptions, they have agreed not to transfer their shares of Magenta common stock for the 180-day period following the closing of the Merger.

The preceding summaries of the Merger Agreement, the Support Agreements and the Lock-Up Agreements do not purport to be complete and are qualified in their entirety by reference to the Merger Agreement, the form of Dianthus Support Agreement, the form of Magenta Support Agreement, the form of Lock-Up Agreement and the form of Contingent Value Rights Agreement, which are filed as Exhibits 2.1, 10.1, 10.2, 10.3 and 10.4, respectively, to this Current Report on Form 8-K and which are incorporated herein by reference. The Merger Agreement has been attached as an exhibit to this Current Report on Form 8-K to provide investors and securityholders with information regarding its terms. It is not intended to provide any other factual information about Dianthus or Magenta or to modify or supplement any factual disclosures about Magenta in its public reports filed with the SEC. The Merger Agreement includes representations, warranties and covenants of Dianthus, Magenta and Merger Sub made solely for the purpose of the Merger Agreement and solely for the benefit of the parties thereto in connection with the negotiated terms of the Merger Agreement. Investors should not rely on the representations, warranties and covenants in the Merger Agreement or any descriptions thereof as characterizations of the actual state of facts or conditions of Dianthus, Magenta or any of their respective affiliates. Moreover, certain of those representations and warranties may not be accurate or complete as of any specified date, may be subject to a contractual standard of materiality different from those generally applicable to SEC filings or may have been used for purposes of allocating risk among the parties to the Merger Agreement, rather than establishing matters of fact.

Stockholder Rights Agreement

On May 2, 2023, the Board approved an Amendment No. 1 (the “Amendment No. 1”) to the Stockholder Rights Agreement by and between Magenta and Computershare Trust Company, N.A. as rights agent, dated March 31, 2023 (the “Rights Agreement”), effective as of May 2, 2023. Amendment No. 1 prevents the approval, execution, delivery or performance of the Merger Agreement, or the consummation prior to the termination of the Merger Agreement of the Merger or any of the other transactions contemplated by the Merger Agreement in accordance with its terms, from, among other things, (i) resulting in a Stock Acquisition Date or Distribution Date (each as defined in the Rights Agreement) or permitting the Rights (as defined in the Rights Agreement) to be exercised or exchanged, (ii) constituting a Section 11(a)(ii) Event or a Section 13 Event (each as defined in the Rights Agreement), and (iii) causing Magenta, Merger Sub or their respective affiliates to be deemed an Acquiring Person (as defined in the Rights Agreement) for any purpose under the Rights Agreement.

The foregoing description of Amendment No. 1 is only a summary, does not purport to be complete and is qualified in its entirety by reference to the Rights Agreement and Amendment No. 1, copies of which are attached as Exhibit 4.1 and Exhibit 4.2, respectively, and are incorporated herein by reference.

To the extent required by this Item, the information included in Item 1.01 of this Current Report on Form 8-K is incorporated herein by reference.

The information set forth in Item 1.01 under the heading “Stockholder Rights Agreement” is incorporated by reference into this Item 3.03.

To the extent required by this Item, the information included in Item 1.01 of this Current Report on Form 8-K is incorporated herein by reference.

To the extent required by this Item, the information included in Item 1.01 of this Current Report on Form 8-K is incorporated herein by reference.

On May 3, 2023, Magenta and Dianthus issued a joint press release announcing the execution of the Merger Agreement. The press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and incorporated herein by reference, except that the information contained on the websites referenced in the press release is not incorporated herein by reference.

Furnished as Exhibit 99.2 hereto and incorporated herein by reference is the investor presentation that will be used by Magenta and Dianthus in connection with the Merger, including the webcast described below.

Magenta plans to host a live webcast presentation to discuss the Merger as well as Dianthus’ platform and pipeline assets at 8:30 am Eastern time on May 3, 2023. The live webcast presentation can be accessed at the Events & Presentations page of Magenta’s website or by using the participant webcast link (edge.media-server.com/mmc/p/26yshfoy). A webcast of the presentation and associated slides will be available on the Investors & Media section of Magenta’s website at investor.magentatx.com and a replay will be archived for 30 days following the presentation. Furnished as Exhibit 99.3 hereto and incorporated herein by reference is the transcript that will be used by Magenta and Dianthus in connection with the webcast.

The information in this Item 7.01, including Exhibits 99.1, 99.2 and 99.3 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended (the “Securities Act”), or the Exchange Act, except as expressly set forth by specific reference in such filing.

Forward-Looking Statements

This Current Report on Form 8-K and the exhibits filed or furnished herewith contain forward-looking statements (including within the meaning of Section 21E of the Exchange Act and Section 27A of the Securities Act) concerning Magenta, Dianthus, the proposed transactions and other matters. These forward-looking statements include express or implied statements relating to structure, timing and completion of the proposed Merger; the combined company’s listing on Nasdaq after closing of the proposed Merger; expectations regarding the ownership structure of the combined company; the expected executive officers and directors of the combined company; each company’s and the combined company’s expected cash position at the closing of the proposed Merger (including completion of Dianthus’ private placement) and cash runway of the combined company; the future operations of the combined company; the nature, strategy and focus of the combined company; the development and commercial potential and potential benefits of any product candidates of the combined company; the location of the combined company’s corporate headquarters; anticipated preclinical and clinical drug development activities and related timelines, including the expected timing for data and other clinical results; the combined company having sufficient resources to advance its pipeline candidates; and other statements that are not historical fact. The words “anticipate,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “might,” “plan,” “possible,” “potential,” “predict,” “project,” “should,” “will,” “would” and similar expressions (including the negatives of these terms or variations of them) may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements are based on current expectations and beliefs concerning future developments and their potential effects. There can be no assurance that future developments affecting Magenta, Dianthus or the proposed transaction will be those that have been anticipated.

These forward-looking statements involve a number of risks, uncertainties (some of which are beyond Magenta’s control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, the risk that the conditions to the closing or consummation of the transaction are not satisfied, including the failure to obtain stockholder approval for the transaction; the risk that the concurrent financing is not completed in a timely manner or at all; uncertainties as to the timing of the consummation of the proposed transaction and the ability of each of Magenta and Dianthus to consummate the transactions contemplated by the proposed transaction; risks related to Magenta’s continued listing on Nasdaq until the closing of the proposed transaction and the combined company’s ability to remain listed following the proposed transaction; risks related to Magenta’s and Dianthus’ ability to correctly estimate their respective operating expenses and expenses associated with the proposed transaction, as well as uncertainties regarding the impact any delay in the closing would have on the anticipated cash resources of the resulting combined company upon closing and other events and unanticipated spending and costs that could reduce the combined company’s cash resources; the occurrence of any event, change or other circumstance or condition that could give rise to the termination of the Merger Agreement or any of the transactions contemplated thereby; the effect of the announcement or pendency of the merger on Magenta’s or Dianthus’ business relationships, operating results and business generally; costs related to the merger; the outcome of any legal proceedings that may be instituted against Magenta, Dianthus or any of their respective directors or officers related to the Merger Agreement or the transactions contemplated thereby; the ability of Magenta or Dianthus to protect their respective intellectual property rights; competitive responses to the proposed transaction; unexpected costs, charges or expenses resulting from the proposed transaction; potential adverse reactions or changes to business relationships resulting from the announcement or completion of the proposed transaction; legislative, regulatory, political and economic developments; and those uncertainties and factors described under the heading “Risk Factors,” “Risk Factor Summary” and “Forward-Looking Statements” in the Magenta’s most recent Annual Report on Form 10-K filed with the SEC on March 23, 2023, as well as discussions of potential risks, uncertainties, and other important factors included in other filings by Magenta from time to time, any risk factors related to Magenta or Dianthus made available to you in connection with the proposed transaction, as well as risk factors associated with companies, such as Dianthus, that operate in the biopharma industry. Should one or more of these risks or uncertainties materialize, or should any of Magenta’s or Dianthus’ assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. Nothing in this Current Report on Form 8-K should be regarded as a representation by any person that the forward-looking statements set forth herein will be achieved or that any of the contemplated results of such forward-looking statements will be achieved. You should not place undue reliance on forward-looking statements in this Current Report on Form 8-K, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Neither Magenta nor Dianthus undertakes or accepts any duty to release publicly any updates or revisions to any forward-looking statements. This Current Report on Form 8-K does not purport to summarize all of the conditions, risks and other attributes of an investment in Magenta or Dianthus.

No Offer or Solicitation

This Current Report on Form 8-K and the exhibits filed or furnished herewith are not intended to and do not constitute (i) a solicitation of a proxy, consent or approval with respect to any securities or in respect of the proposed transaction or (ii) an offer to sell or the solicitation of an offer to subscribe for or buy or an invitation to purchase or subscribe for any securities pursuant to the proposed transaction or otherwise, nor shall there be any sale, issuance or transfer of securities in any jurisdiction in contravention of applicable law. No offer of securities shall be made except by means of a prospectus meeting the requirements of the Securities Act or an exemption therefrom. Subject to certain exceptions to be approved by the relevant regulators or certain facts to be ascertained, the public offer will not be made directly or indirectly, in or into any jurisdiction where to do so would constitute a violation of the laws of such jurisdiction, or by use of the mails or by any means or instrumentality (including without limitation, facsimile transmission, telephone and the internet) of interstate or foreign commerce, or any facility of a national securities exchange, of any such jurisdiction.

NEITHER THE SEC NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THE SECURITIES OR DETERMINED IF THIS CURRENT REPORT ON FORM 8-K AND THE EXHIBITS FILED OR FURNISHED HEREWITH ARE TRUTHFUL OR COMPLETE.

Important Additional Information About the Proposed Transaction Will be Filed with the SEC

This Current Report on Form 8-K and the exhibits filed or furnished herewith are not substitutes for the registration statement or for any other document that Magenta may file with the SEC in connection with the proposed transaction. In connection with the proposed transaction between Magenta and Dianthus, Magenta intends to file relevant materials with the SEC, including a registration statement on Form S-4 that will contain a proxy statement/prospectus of Magenta. MAGENTA URGES INVESTORS AND STOCKHOLDERS TO READ THE REGISTRATION STATEMENT, PROXY STATEMENT/PROSPECTUS AND ANY OTHER RELEVANT DOCUMENTS THAT MAY BE FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY IF AND WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT MAGENTA, DIANTHUS, THE PROPOSED TRANSACTION AND RELATED MATTERS. Investors and stockholders will be able to obtain free copies of the proxy statement/prospectus and other documents filed by Magenta with the SEC (when they become available) through the website maintained by the SEC at www.sec.gov. In addition, investors and stockholders should note that Magenta communicates with investors and the public using its website (www.magentatx.com) and the investor relations website (investors.magentatx.com) where anyone will be able to obtain free copies of the proxy statement/prospectus and other documents filed by Magenta with the SEC and stockholders are urged to read the proxy statement/prospectus and the other relevant materials when they become available before making any voting or investment decision with respect to the proposed transaction.

Participants in the Solicitation

Magenta, Dianthus and their respective directors and executive officers may be deemed to be participants in the solicitation of proxies from stockholders in connection with the proposed transaction. Information about Magenta’s directors and executive officers including a description of their interests in Magenta is included in Magenta’s most recent Annual Report on Form 10-K, including any information incorporated therein by reference, as filed with the SEC. Additional information regarding these persons and their interests in the proposed transaction will be included in the proxy statement/prospectus relating to the proposed transaction when it is filed with the SEC. These documents can be obtained free of charge from the sources indicated above.

(d) Exhibits

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Exhibit 2.1

AGREEMENT AND PLAN OF MERGER

among:

MAGENTA THERAPEUTICS, INC.;

DIO MERGER SUB, INC.; and

DIANTHUS THERAPEUTICS, INC.

Dated as of May 2, 2023

Table of Contents

Exhibits:

AGREEMENT AND PLAN OF MERGER

THIS AGREEMENT AND PLAN OF MERGER (this “Agreement”) is made and entered into as of May 2, 2023, by and among MAGENTA THERAPEUTICS, INC., a Delaware corporation (“Magenta”), DIO MERGER SUB, Inc., a Delaware corporation and wholly owned subsidiary of Magenta (“Merger Sub”), and DIANTHUS THERAPEUTICS, INC., a Delaware corporation (the “Company”). Certain capitalized terms used in this Agreement are defined Section 1.

RECITALS

A. Magenta and the Company intend to effect a merger of Merger Sub with and into the Company (the “Merger”) in accordance with this Agreement and the DGCL. Upon consummation of the Merger, Merger Sub will cease to exist and the Company will become a wholly owned subsidiary of Magenta.

B. The Parties intend that the Merger qualifies as a “reorganization” within the meaning of Section 368(a) of the Code and the Treasury Regulations, and that this Agreement be, and hereby is, adopted as a “plan of reorganization” for the purposes of Section 368 of the Code and Treasury Regulations Sections 1.368-2(g) and 1.368-3.

C. The Magenta Board has (i) determined that the Contemplated Transactions are fair to, advisable and in the best interests of Magenta and its stockholders, (ii) approved and declared advisable this Agreement and the Contemplated Transactions, including the issuance of shares of Magenta Common Stock to the stockholders of the Company pursuant to the terms of this Agreement and (iii) determined to recommend, upon the terms and subject to the conditions set forth in this Agreement, that the stockholders of Magenta vote to approve this Agreement and thereby approve the Contemplated Transactions, including the issuance of shares of Magenta Common Stock to the stockholders of the Company pursuant to the terms of this Agreement and, if deemed necessary by the Parties, an amendment to Magenta’s certificate of incorporation to effect the Nasdaq Reverse Split, and against any competing proposals.

D. The Merger Sub Board has (i) determined that the Contemplated Transactions are fair to, advisable, and in the best interests of Merger Sub and its sole stockholder, (ii) approved and declared advisable this Agreement and the Contemplated Transactions and (iii) determined to recommend, upon the terms and subject to the conditions set forth in this Agreement, that the stockholder of Merger Sub votes to adopt this Agreement and thereby approve the Contemplated Transactions.

E. The Company Board has (i) determined that the Contemplated Transactions are fair to, advisable and in the best interests of the Company and its stockholders, (ii) approved and declared advisable this Agreement and the Contemplated Transactions and (iii) determined to recommend, upon the terms and subject to the conditions set forth in this Agreement, that the stockholders of the Company vote to adopt this Agreement and thereby approve the Contemplated Transactions.

F. Concurrently with the execution and delivery of this Agreement and as a condition and inducement to the Company’s willingness to enter into this Agreement, each of the officers, directors and stockholders set forth on Section A of the Magenta Disclosure Schedule (solely in their capacity as stockholders of Magenta) are executing support agreements in favor of the Company in substantially the form attached hereto as Exhibit A-1 (the “Magenta Stockholder Support Agreement”), pursuant to which such Persons have, subject to the terms and conditions set forth therein, agreed to vote all of their shares of capital stock of Magenta in favor of the approval of this Agreement and thereby approve the Contemplated Transactions, and, if deemed necessary by Magenta, an amendment to Magenta’s certificate of incorporation to effect the Nasdaq Reverse Split, and against any competing proposals.

G. Concurrently with the execution and delivery of this Agreement and as a condition and inducement to Magenta’s willingness to enter into this Agreement, each of the officers, directors and stockholders of the Company listed on Section A of the Company Disclosure Schedule (solely in their capacity as stockholders of the Company) are executing support agreements in favor of Magenta in substantially the form attached hereto as Exhibit A-2 (the “Company Stockholder Support Agreement”), pursuant to which such Persons have, subject to the terms and conditions set forth therein, agreed to vote all of their shares of Company Capital Stock in favor of the adoption of this Agreement and thereby approve the Contemplated Transactions and against any competing proposals.

H. Concurrently with the execution and delivery of this Agreement and as a condition and inducement to Magenta’s and the Company’s willingness to enter into this Agreement, all of the stockholders of the Company or Magenta listed on Section B of the Company Disclosure Schedule are executing lock-up agreements in substantially the form attached hereto as Exhibit B (the “Lock-Up Agreement,” and collectively, the “Lock-Up Agreements”).

I. It is expected that within two (2) Business Days after the Registration Statement is declared effective under the Securities Act, the holders of shares of Company Capital Stock sufficient to adopt and approve this Agreement and the Merger as required under the DGCL and the Company’s certificate of incorporation and bylaws will execute and deliver an action by written consent adopting this Agreement, in form and substance reasonably acceptable to Magenta, in order to obtain the Required Company Stockholder Vote.

J. Concurrently with the execution and delivery of this Agreement, certain investors have executed a Subscription Agreement in the form attached hereto as Exhibit C among the Company and the Persons named therein (representing an aggregate commitment no less than the Concurrent Investment Amount) (the “Subscription Agreement”), pursuant to which such Persons will have agreed to purchase in the amounts set forth therein (i) shares of Company Common Stock and (ii) pre-funded Company Warrants, in each case, immediately prior to the Closing (the “Company Pre-Closing Financing”).

K. Concurrently with the execution and delivery of this Agreement, the Stockholder Rights Agreement, dated March 31, 2023, between Magenta and Computershare Trust Company, N.A., as Rights Agent (the “Rights Agreement”), has been amended such that the Company is not an Acquiring Person (as defined in the Rights Agreement) thereunder.

AGREEMENT

The Parties, intending to be legally bound, agree as follows:

Section 1. Definitions and Interpretative Provisions.

1.1 Definitions.

(a) For purposes of the Agreement (including this Section 1):

“Acceptable Confidentiality Agreement” means a confidentiality agreement containing terms not materially less restrictive in the aggregate to the counterparty thereto than the terms of the Confidentiality Agreement, except such confidentiality agreement need not contain any standstill, non-solicitation or no hire provisions. Notwithstanding the foregoing, a Person who has previously entered into a confidentiality agreement with Magenta relating to a potential Acquisition Proposal on terms that are not materially less restrictive than the Confidentiality Agreement with respect to the scope of coverage and restrictions on disclosure and use shall not be required to enter into a new or revised confidentiality agreement, and such existing confidentiality agreement shall be deemed to be an Acceptable Confidentiality Agreement.

2

“Acquisition Inquiry” means, with respect to a Party, an inquiry, indication of interest or request for information (other than an inquiry, indication of interest or request for information made or submitted by the Company, on the one hand, or Magenta, on the other hand, to the other Party) that could reasonably be expected to lead to an Acquisition Proposal.

“Acquisition Proposal” means, with respect to a Party, any offer or proposal, whether written or oral (other than an offer or proposal made or submitted by or on behalf of the Company or any of its Affiliates, on the one hand, or by or on behalf of Magenta or any of its Affiliates, on the other hand, to the other Party) contemplating or otherwise relating to any Acquisition Transaction with such Party, other than the Magenta Legacy Transaction and the Company Pre-Closing Financing.

“Acquisition Transaction” means any transaction or series of related transactions (other than the Magenta Legacy Transaction) involving:

(a) any merger, consolidation, amalgamation, share exchange, business combination, issuance of securities, acquisition of securities, reorganization, recapitalization, tender offer, exchange offer or other similar transaction: (i) in which a Party is a constituent Entity, (ii) in which a Person or “group” (as defined in the Exchange Act and the rules promulgated thereunder) of Persons directly or indirectly acquires beneficial or record ownership of securities representing more than 20% of the outstanding securities of any class of voting securities of a Party or any of its Subsidiaries or (iii) in which a Party or any of its Subsidiaries issues securities representing more than 20% of the outstanding securities of any class of voting securities of such Party or any of its Subsidiaries; provided, however, in the case of the Company, the Company Pre-Closing Financing shall not be an Acquisition Transaction; or

(b) any sale, lease, exchange, transfer, license, acquisition or disposition of any business or businesses or assets that constitute or account for 20% or more of the consolidated book value or the fair market value of the assets of a Party and its Subsidiaries, taken as a whole.

“Affiliate” shall have the meaning given to such term in Rule 145 under the Securities Act.

“Affordable Care Act” means the Patient Protection and Affordable Care Act.

“Anticipated Closing Date” means the anticipated Closing Date, as agreed upon by Magenta and the Company.

“Business Day” means any day other than a day on which banks in the State of New York are authorized or obligated to be closed.

“COBRA” means the Consolidated Omnibus Budget Reconciliation Act of 1985, as set forth in Section 4980B of the Code and Section 6 of Title I of ERISA.

“Code” means the Internal Revenue Code of 1986, as amended.

“Company Associate” means any current employee, independent contractor, officer or director of the Company or any of its Subsidiaries.

“Company Board” means the board of directors of the Company.

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“Company Capital Stock” means the Company Common Stock and the Company Preferred Stock.

“Company Capitalization Representations” means the representations and warranties of the Company set forth in Sections 3.6(a) and 3.6(d).

“Company Common Stock” means the Common Stock, $0.0001 par value per share, of the Company.

“Company Contract” means any Contract: (a) to which the Company or any of its Subsidiaries is a Party, (b) by which the Company or any of its Subsidiaries is or may become bound or under which the Company or any of its Subsidiaries has, or may become subject to, any obligation or (c) under which the Company or any of its Subsidiaries has or may acquire any right or interest.

“Company Employee Plan” means any Employee Plan that the Company or any of its Subsidiaries (i) sponsors, maintains, administers, or contributes to, or (ii) provides benefits under or through, or (iii) has any obligation to contribute to or provide benefits under or through, or (iv) may reasonably be expected to have any Liability, or (v) utilizes to provide benefits to or otherwise cover any current or former employee, officer, director or other service provider of the Company or any of its Subsidiaries (or their spouses, dependents, or beneficiaries).

“Company Equity Incentive Plan” means the Company’s 2019 Stock Plan.

“Company Fundamental Representations” means the representations and warranties of the Company set forth in Sections 3.1(a), 3.1(b), 3.2, 3.3, 3.4 and 3.20.

“Company IP Rights” means all Intellectual Property owned, licensed, or controlled by the Company or its Subsidiaries that is necessary for, or used or held for use in, the operation of the business of the Company and its Subsidiaries as presently conducted.

“Company IP Rights Agreement” means any Contract governing, related to or pertaining to any Company IP Rights other than any confidential information provided under confidentiality agreements.

“Company Key Employee” means (i) any executive officer of the Company or any of its Subsidiaries; and (ii) any employee of the Company or any of its Subsidiaries that reports directly to the Company Board or to an executive officer of the Company or any of its Subsidiaries.

“Company Material Adverse Effect” means any Effect that, considered together with all other Effects that have occurred prior to the date of determination of the occurrence of a Company Material Adverse Effect, has or would reasonably be expected to have a material adverse effect on the business, financial condition, assets, liabilities or results of operations of the Company or its Subsidiaries, taken as a whole; provided, however, that Effects arising or resulting from the following shall not be taken into account in determining whether there has been a Company Material Adverse Effect: (a) the announcement of the Agreement or the pendency of the Contemplated Transactions, (b) the taking of any action, or the failure to take any action, by the Company that is required to comply with the terms of the Agreement, (c) any natural disaster, calamity or epidemics, pandemics (including COVID-19 and any precautionary or emergency measures, recommendations, protocols or orders taken or issued by any Person in response to COVID-19) or other force majeure events, or any act or threat of terrorism or war, any armed hostilities or terrorist activities (including any escalation or general worsening of any of the foregoing) anywhere in the world or any governmental or other response or reaction to any of the foregoing, (d) any change in GAAP or applicable Law or the interpretation thereof, (e) general economic or political conditions or conditions

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generally affecting the industries in which the Company and its Subsidiaries operate or (f) any change in the cash position of the Company and its Subsidiaries which results from operations in the Ordinary Course of Business; except in each case with respect to clauses (c), (d) and (e), to the extent disproportionately affecting the Company and its Subsidiaries, taken as a whole, relative to other similarly situated companies in the industries in which the Company and its Subsidiaries operate.

“Company Merger Shares” means the product determined by multiplying (i) the Post-Closing Magenta Shares by (ii) the Company Allocation Percentage, in which:

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“Company Options” means options or other rights to purchase shares of Company Capital Stock issued by the Company.

“Company Preferred Stock” means the Company Series Seed Preferred Stock, the Company Series Seed 2 Preferred Stock and the Company Series A Preferred Stock.

“Company Registered IP” means all Company IP Rights that are owned or exclusively licensed by the Company that are registered, filed or issued under the authority of, with or by any Governmental Authority, including all patents, registered copyrights and registered trademarks and all applications and registrations for any of the foregoing.

“Company Series A Preferred Stock” means a series of the Company’s preferred stock designated as Series A Preferred Stock, $0.0001 par value per share.

“Company Series Seed Preferred Stock” means a series of the Company’s preferred stock designated as Series Seed Preferred Stock, $0.0001 par value per share.

“Company Series Seed 2 Preferred Stock” means a series of the Company’s preferred stock designated as Series Seed 2 Preferred Stock, $0.0001 par value per share.

“Company Triggering Event” shall be deemed to have occurred if: (a) the Company Board shall have made a Company Board Adverse Recommendation Change; (b) the Company Board or any committee thereof shall have publicly approved, endorsed or recommended any Acquisition Proposal; or (c) the Company shall have entered into any letter of intent or similar document or any Contract relating to any Acquisition Proposal.

“Company Warrants” means warrants to purchase shares of Company Capital Stock issued by the Company.

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“Concurrent Investment Amount” means $70,000,000.

“Confidentiality Agreement” means the Confidentiality Agreement dated February 22, 2023, between the Company and Magenta.

“Consent” means any approval, consent, ratification, permission, waiver or authorization (including any Governmental Authorization).

“Contemplated Transactions” means the Merger and the other transactions contemplated by the Agreement, including the CVR Agreement, the Magenta Legacy Transaction, the Company Pre-Closing Financing and the Nasdaq Reverse Split (to the extent applicable and deemed necessary by Magenta and the Company).

“Contract” means, with respect to any Person, any written agreement, contract, subcontract, lease (whether for real or personal property), mortgage, license, or other legally binding commitment or undertaking of any nature to which such Person is a party or by which such Person or any of its assets are bound or affected under applicable Law.

“DGCL” means the General Corporation Law of the State of Delaware.

“Effect” means any effect, change, event, circumstance, or development.

“Employee Plan” means (A) an “employee benefit plan” within the meaning of Section 3(3) of ERISA whether or not subject to ERISA; (B) other plan, program, policy or arrangement providing for stock options, stock purchases, equity-based compensation, bonuses (including any annual bonuses and retention bonuses) or other incentives, severance pay, deferred compensation, employment, compensation, change in control or transaction bonuses, supplemental, vacation, retirement benefits (including post-retirement health and welfare benefits), pension benefits, profit-sharing benefits, fringe benefits, life insurance benefits, perquisites, health benefits, medical benefits, dental benefits, vision benefits, and all other employee benefit plans, agreements, and arrangements, not described in (A) above; and (C) all other plans, programs, policies or arrangements providing compensation to employees, consultants and non-employee directors.

“Encumbrance” means any lien, pledge, hypothecation, charge, mortgage, security interest, lease, exclusive license, option, easement, reservation, servitude, adverse title, claim, infringement, interference, option, right of first refusal, preemptive right, community property interest or restriction or encumbrance of any nature (including any restriction on the voting of any security, any restriction on the transfer of any security or other asset, any restriction on the receipt of any income derived from any asset, any restriction on the use of any asset and any restriction on the possession, exercise or transfer of any other attribute of ownership of any asset).

“Enforceability Exceptions” means the (a) Laws of general application relating to bankruptcy, insolvency and the relief of debtors and (b) rules of law governing specific performance, injunctive relief and other equitable remedies.

“Entity” means any corporation (including any nonprofit corporation), partnership (including any general partnership, limited partnership or limited liability partnership), joint venture, estate, trust, company (including any company limited by shares, limited liability company or joint stock company), firm, society or other enterprise, association, organization or entity, and each of its successors.

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“Environmental Law” means any federal, state, local or foreign Law relating to pollution or protection of human health or the environment (including ambient air, surface water, ground water, land surface or subsurface strata), including any law or regulation relating to emissions, discharges, releases or threatened releases of Hazardous Materials, or otherwise relating to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Hazardous Materials.

“ERISA” means the Employee Retirement Income Security Act of 1974, as amended.

“ERISA Affiliate” means, with respect to any Entity, any other Person that would be treated as a single employer with such Entity or part of the same “controlled group” as such Entity under Sections 414(b),(c),(m) or (o) of the Code.

“Exchange Act” means the Securities Exchange Act of 1934, as amended.

“Governmental Authority” means any: (a) nation, state, commonwealth, province, territory, county, municipality, district or other jurisdiction of any nature, (b) federal, state, local, municipal, foreign, supra-national or other government, (c) governmental or quasi-governmental authority of any nature (including any governmental division, department, agency, commission, bureau, instrumentality, official, ministry, fund, foundation, center, organization, unit, body or Entity and any court or other tribunal, and for the avoidance of doubt, any taxing authority) or (d) self-regulatory organization (including Nasdaq).

“Governmental Authorization” means any: (a) permit, license, certificate, franchise, permission, variance, exception, order, approval, clearance, registration, qualification or authorization issued, granted, given or otherwise made available by or under the authority of any Governmental Authority or pursuant to any Law or (b) right under any Contract with any Governmental Authority.

“Hazardous Materials” means any pollutant, chemical, substance and any toxic, infectious, carcinogenic, reactive, corrosive, ignitable or flammable chemical, or chemical compound, or hazardous substance, material or waste, whether solid, liquid or gas, that is subject to regulation, control or remediation under any Environmental Law, including without limitation, crude oil or any fraction thereof, and petroleum products or by-products.

“Intellectual Property” means: (a) United States, foreign and international patents, patent applications, including all provisionals, nonprovisionals, substitutions, divisionals, continuations, continuations-in-part, reissues, extensions, supplementary protection certificates, reexaminations, term extensions, certificates of invention and the equivalents of any of the foregoing, statutory invention registrations, invention disclosures and inventions (collectively, “Patents”), (b) trademarks, service marks, trade names, domain names, corporate names, brand names, URLs, trade dress, logos and other source identifiers, including registrations and applications for registration thereof and goodwill associated therewith, (c) copyrights, including registrations and applications for registration thereof, (d) software, including all source code, object code and related documentation, (e) formulae, customer lists, trade secrets, know-how, confidential information and other proprietary rights and intellectual property, whether patentable or not, and (f) all United States and foreign rights arising under or associated with any of the foregoing.

“IRS” means the United States Internal Revenue Service.

“Knowledge” means, with respect to an individual, that such individual is actually aware of the relevant fact or such individual would reasonably be expected to know such fact in the ordinary course of the performance of such individual’s employment responsibilities. Any Person that is an Entity shall have Knowledge if any executive officer or director of such Person as of the date such knowledge is imputed has

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or should reasonably be expected to have Knowledge of such fact or other matter. With respect to any matters relating to Intellectual Property, such awareness or reasonable expectation to have knowledge does not require any such individual to conduct or have conducted or obtain or have obtained any freedom to operate opinions of counsel or any Intellectual Property rights clearance searches.

“Law” means any federal, state, national, supra-national, foreign, local or municipal or other law, statute, constitution, principle of common law, resolution, ordinance, code, edict, decree, rule, regulation, ruling or requirement issued, enacted, adopted, promulgated, implemented or otherwise put into effect by or under the authority of any Governmental Authority (including under the authority of Nasdaq or the Financial Industry Regulatory Authority).

“Legal Proceeding” means any action, suit, litigation, arbitration, proceeding (including any civil, criminal, administrative, investigative or appellate proceeding), hearing, inquiry, audit, examination or investigation commenced, brought, conducted or heard by or before, or otherwise involving, any court or other Governmental Authority or any arbitrator or arbitration panel.

“Magenta Associate” means any current employee, independent contractor, officer or director of Magenta or any of its Subsidiaries.

“Magenta Balance Sheet” means the audited balance sheet of Magenta as of December 31, 2022, included in Magenta’s Report on Form 10-K for the year ended December 31, 2022, as filed with the SEC.

“Magenta Board” means the board of directors of Magenta.

“Magenta Capitalization Representations” means the representations and warranties of Magenta and Merger Sub set forth in Sections 4.6(a) and 4.6(d).

“Magenta Closing Price” means the volume weighted average closing trading price of a share of Magenta Common Stock on Nasdaq for the five (5) consecutive trading days ending three (3) trading days immediately prior to the date of the public announcement of this Agreement.

“Magenta Common Stock” means the common stock, $0.001 par value per share, of Magenta.

“Magenta Contract” means any Contract: (a) to which Magenta is a party, (b) by which Magenta or any Magenta IP Rights or any other asset of Magenta is or may become bound or under which Magenta has, or may become subject to, any obligation or (c) under which Magenta has or may acquire any right or interest.

“Magenta Employee Plan” means any Employee Plan that Magenta or any of its Subsidiaries (i) sponsors, maintains, administers, or contributes to, or (ii) provides benefits under or through, or (iii) has any obligation to contribute to or provide benefits under or through, or (iv) may reasonably be expected to have any Liability, or (v) utilizes to provide benefits to or otherwise cover any current or former employee, officer, director or other service provider of Magenta or any of its Subsidiaries (or their spouses, dependents, or beneficiaries).

“Magenta Fundamental Representations” means the representations and warranties of Magenta and Merger Sub set forth in Sections 4.1(a), 4.1(b), 4.2, 4.3, 4.4 and 4.21.

“Magenta IP Rights” means all Intellectual Property owned, licensed or controlled by Magenta that is necessary for, or used or held for use in, the operation of the business of Magenta.

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“Magenta IP Rights Agreement” means any Contract governing, related or pertaining to any Magenta IP Rights.

“Magenta Key Employee” means (i) an executive officer of Magenta; and (ii) any employee of Magenta that reports directly to the Magenta Board or to an executive officer of Magenta.

“Magenta Legacy Business” means the business of Magenta as conducted at any time prior to the date of this Agreement, including but not limited to business related to the assets listed on Section 1.1(a) of the Magenta Disclosure Schedule.

“Magenta Material Adverse Effect” means any Effect that, considered together with all other Effects that have occurred prior to the date of determination of the occurrence of the Magenta Material Adverse Effect, has or would reasonably be expected to have a material adverse effect on the business, financial condition, assets, liabilities or results of operations of Magenta or any of its Subsidiaries, taken as a whole; provided, however, that Effects arising or resulting from the following shall not be taken into account in determining whether there has been a Magenta Material Adverse Effect: (a) the announcement of the Agreement or the pendency of the Contemplated Transactions, (b) any change in the stock price or trading volume of Magenta Common Stock (it being understood, however, that any Effect causing or contributing to any change in stock price or trading volume of Magenta Common Stock may be taken into account in determining whether a Magenta Material Adverse Effect has occurred, unless such Effects are otherwise excepted from this definition), (c) the taking of any action, or the failure to take any action, by Magenta that is required to comply with the terms of the Agreement, (d) any natural disaster, calamity or epidemics, pandemics (including COVID-19 and any precautionary or emergency measures, recommendations, protocols or orders taken or issued by any Person in response to COVID-19) or other force majeure events, or any act or threat of terrorism or war, any armed hostilities or terrorist activities (including any escalation or general worsening of any of the foregoing) anywhere in the world, or any governmental or other response or reaction to any of the foregoing, (e) any change in GAAP or applicable Law or the interpretation thereof or (f) general economic or political conditions or conditions generally affecting the industries in which Magenta or any of its Subsidiaries operates; except, in each case with respect to clauses (d), (e) and (f), to the extent materially and disproportionately affecting Magenta and any its Subsidiaries, taken as a whole, relative to other similarly situated companies in the industries in which Magenta or any of its Subsidiaries operates. Notwithstanding the above, a delisting of Magenta Common Stock on Nasdaq shall constitute a Magenta Material Adverse Effect, provided that the Company has not refused or unreasonably delayed its consent to reasonable actions by Magenta to maintain the listing of Magenta Common Stock on Nasdaq.

“Magenta Net Cash” means without duplication, (i) Magenta’s unrestricted cash and cash equivalents and marketable securities determined, to the extent in accordance with GAAP, in a manner consistent with the manner in which such items were historically determined and in accordance with the financial statements (including any related notes) contained or incorporated by reference in the Magenta SEC Documents and the Magenta Balance Sheet, plus (ii) all prepaid expenses set forth on Section 1.1(b) of the Magenta Disclosure Schedule (if any), minus (iii) the sum of Magenta’s consolidated short-term and long-term contractual obligations and liabilities accrued at the Closing Date, in each case determined in accordance with GAAP and, to the extent in accordance with GAAP, in a manner consistent with the manner in which such items were historically determined and in accordance with the financial statements (including any related notes) contained or incorporated by reference in the Magenta SEC Documents and the Magenta Balance Sheet, minus (iv) fees and expenses incurred with respect to the Contemplated Transactions, including for the avoidance of doubt, the Transaction Expenses of Magenta to the extent unpaid as of the Closing, minus (v) the cash cost of change in control payments payable to employees of Magenta solely as a result of the consummation of the Contemplated Transactions, minus (vi) all Liabilities related to Magenta’s or any of its Subsidiaries’ lease obligations, minus (vii) 50% of the aggregate costs

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associated with obtaining the “D&O tail policy” pursuant to Section 6.8, minus (viii) any Taxes of Magenta and its Subsidiaries for Tax periods (or portions thereof) ending on or before the Closing Date, minus, (ix) all costs and expenses relating to the winding down of Magenta Legacy Business, including the sale, license or other disposition of any or all of the Magenta Legacy Business, plus (x) receivables representing refunds of value added taxes that are expected to be received from taxing authorities in the United Kingdom set forth on Section 1.1(b) of the Magenta Disclosure Schedule, net of any amounts that are contested or denied by the applicable Governmental Authority, plus (xi) $300,000 for each week, or portion thereof, after May 15, 2023 by which the filing of the Form S-4 is delayed exclusively as a result of the Company’s failure to provide the Company Required S-4 Information, which shall begin accruing on May 16, 2023 (for example, if the filing of the Form S-4 is delayed until (A) May 22, 2023 as a result of such failure then $300,000 will be added to Magenta Net Cash or (B) May 23, 2023 as a result of such failure then $600,000 will be added to Magenta Net Cash).

“Magenta Options” means options or other rights to purchase shares of Magenta Common Stock granted by Magenta, including pursuant to any Magenta Stock Plan.

“Magenta Preferred Stock” means (i) the undesignated preferred stock, par value $0.001 per share and (ii) the Series A Junior Participating Cumulative Preferred Stock, par value $0.001 per share, of Magenta.

“Magenta Registered IP” means all Magenta IP Rights that are owned or exclusively licensed by Magenta that are registered, filed or issued under the authority of, with or by any Governmental Authority, including all patents, registered copyrights and registered trademarks and all applications for any of the foregoing.

“Magenta Restricted Stock Units” means any equity award with respect to Magenta Common Stock that represents the right to receive in the future shares of Magenta Common Stock pursuant to any Magenta Stock Plan.

“Magenta Rights” means the preferred stock purchase rights issued by Magenta pursuant to the Rights Agreement.

“Magenta Triggering Event” shall be deemed to have occurred if: (a) Magenta shall have failed to include in the Proxy Statement the Magenta Board Recommendation, (b) the Magenta Board or any committee thereof shall have made a Magenta Board Adverse Recommendation Change or approved, endorsed or recommended any Acquisition Proposal or (c) Magenta shall have entered into any letter of intent or similar document or any Contract relating to any Acquisition Proposal (other than an Acceptable Confidentiality Agreement permitted pursuant to Section 5.4).

“Merger Sub Board” means the board of directors of Merger Sub.

“Multiemployer Plan” means a “multiemployer plan,” as defined in Section 3(37) or 4001(a)(3) of ERISA.

“Multiple Employer Plan” means a “multiple employer plan” within the meaning of Section 413(c) of the Code or Section 3(40) of ERISA.

“Multiple Employer Welfare Arrangement” means a “multiple employer welfare arrangement” within the meaning of Section 3(40) of ERISA.

“Nasdaq” means The Nasdaq Stock Market.

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“Nasdaq Reverse Split” means a reverse stock split of all outstanding shares of Magenta Common Stock effected by Magenta for the purpose of maintaining compliance with Nasdaq listing standards.

“Order” means any judgment, order, writ, injunction, ruling, decision or decree of (that is binding on a Party), or any plea agreement, corporate integrity agreement, resolution agreement or deferred prosecution agreement with, or any settlement under the jurisdiction of, any court or Governmental Authority.

“Ordinary Course of Business” means, in the case of each of the Company and Magenta, such actions taken in the ordinary course of its normal operations and consistent with its past practices; provided, however, that during the Pre-Closing Period, the Ordinary Course of Business of Magenta shall also include actions required to effect and effecting, in one or more transactions, the sale, divestiture, licensing or winding down of the Magenta Legacy Business or the sale, license or other disposition of any or all of the Magenta Legacy Business; provided, however, that to the extent such sale, license or other disposition results in ongoing post-Closing obligations to Magenta or Company, the terms of such sale, license or other disposition shall be reasonably acceptable to Company.

“Organizational Documents” means, with respect to any Person (other than an individual), (a) the certificate or articles of association or incorporation or organization or limited partnership or limited liability company, and any joint venture, limited liability company, operating or partnership agreement and other similar documents adopted or filed in connection with the creation, formation or organization of such Person and (b) all bylaws, regulations and similar documents or agreements relating to the organization or governance of such Person, in each case, as amended or supplemented.

“Out of the Money Magenta Options” shall mean Magenta Options with an exercise price greater than the Magenta Closing Price.

“Party” or “Parties” means the Company, Merger Sub and Magenta.

“Permitted Alternative Agreement” means a definitive agreement that contemplates or otherwise relates to an Acquisition Transaction that constitutes a Superior Offer.

“Permitted Encumbrance” means (a) any statutory liens for current Taxes not yet due and payable or for Taxes that are being contested in good faith by the appropriate proceedings and for which adequate reserves have been made on the Company Balance Sheet or the Magenta Balance Sheet, as applicable, in accordance with GAAP, (b) minor liens that have arisen in the Ordinary Course of Business and that do not (in any case or in the aggregate) materially detract from the value of the assets subject thereto or materially impair the operations of the Company or Magenta, as applicable, (c) statutory liens to secure obligations to landlords, lessors or renters under leases or rental agreements, (d) deposits or pledges made in connection with, or to secure payment of, workers’ compensation, unemployment insurance or similar programs mandated by Law, (e) statutory liens in favor of carriers, warehousemen, mechanics and materialmen, to secure claims for labor, materials or supplies and (f) liens arising under applicable securities Law.

“Person” means any individual, Entity or Governmental Authority.

“Personal Information” means data and information concerning an identifiable natural person.

“Privacy Laws” mean, collectively, (i) all applicable Laws relating to data privacy, data protection, data security, trans-border data flow, data loss, data theft or breach notification with respect to the collection, handling, use, processing, maintenance, storage, disclosure or transfer of Personal Information enacted, adopted, promulgated or applied by any Governmental Authority, including the applicable legally

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binding requirements set forth in applicable regulations and agreements containing consent orders published by regulatory authorities of competent jurisdiction such as, as applicable, the U.S. Federal Trade Commission, U.S. Federal Communications Commission, and state data protection authorities, including but not limited to HIPAA; (ii) the internal privacy policy of the Company and any public statements that the Company has made regarding its privacy policies and practices; (iii) third party privacy policies with which the Company has been or is contractually obligated to comply; and (iv) any applicable rules of any applicable self-regulatory organizations in which the Company is or has been a member and/or with which the Company is or has been contractually obligated to comply relating to data privacy, data protection, data security, trans-border data flow, data loss, data theft or breach notification with respect to the collection, handling, use, processing, maintenance, storage, disclosure or transfer of Personal Information.

“Representatives” means directors, officers, employees, agents, attorneys, accountants, investment bankers, advisors and representatives.

“Sarbanes-Oxley Act” means the Sarbanes-Oxley Act of 2002.

“SEC” means the United States Securities and Exchange Commission.

“Securities Act” means the Securities Act of 1933, as amended.

“Subsequent Transaction” means any Acquisition Transaction (with all references to 20% in the definition of Acquisition Transaction being treated as references to 50% for these purposes).

“Subsidiary” means, with respect to an Entity, a Person if such Person directly or indirectly owns or purports to own, beneficially or of record, (a) an amount of voting securities or other interests in such Entity that is sufficient to enable such Person to elect at least a majority of the members of such entity’s board of directors or other governing body or (b) at least 50% of the outstanding equity, voting, beneficial or financial interests in such Entity.

“Superior Offer” means an unsolicited bona fide written Acquisition Proposal (with all references to 20% in the definition of Acquisition Transaction being treated as references to 50% for these purposes) that: (a) was not obtained or made as a direct or indirect result of a breach of (or in violation of) the Agreement, (b) is on terms and conditions that the Magenta Board or the Company Board, as applicable, determines in good faith, based on such matters that it deems relevant (including the likelihood of consummation thereof and the financing terms thereof), as well as any written offer by the other Party to the Agreement to amend the terms of the Agreement, and following consultation with its outside legal counsel and financial advisors, if any, are more favorable, from a financial point of view, to Magenta’s stockholders or the Company’s stockholders, as applicable, than the terms of the Contemplated Transactions, (c) is not subject to any financing conditions (and if financing is required, such financing is then fully committed to the third party) and (d) is reasonably capable of being completed on the terms proposed without unreasonable delay.

“Tax” means any U.S. federal, state, local, foreign or other tax, including any income tax, franchise tax, capital gains tax, gross receipts tax, value-added tax, surtax, estimated tax, employment tax, unemployment tax, national health insurance tax, environmental tax, excise tax, ad valorem tax, transfer tax, conveyance tax, stamp tax, sales tax, use tax, property tax, business tax, withholding tax, payroll tax, social security tax, customs duty, licenses tax, alternative or add-on minimum or other tax or similar charge, duty, levy, fee, tariff, impost, obligation or assessment in the nature of a tax (whether imposed directly or through withholding and whether or not disputed), and including any fine, penalty, addition to tax, interest or additional amount imposed by a Governmental Authority with respect thereto (or attributable to the nonpayment thereof).

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“Tax Return” means any return (including any information return), report, statement, declaration, claim or refund, estimate, schedule, notice, notification, form, election, certificate or other document or information, and any amendment or supplement to any of the foregoing, filed or required to be filed with any Governmental Authority (or provided to a payee) in connection with the determination, assessment, collection or payment of any Tax or in connection with the administration, implementation or enforcement of or compliance with any Law relating to any Tax.

“Transaction Expenses” means, subject to Section 10.3(a), with respect to a Party, the aggregate amount (without duplication) of all costs, fees and expenses incurred by such Party or any of its Subsidiaries (including Merger Sub), or for which such Party or any of its Subsidiaries are or may become liable in connection with the Contemplated transactions and the negotiation, preparation and execution of this Agreement or any other agreement, document, instrument, filing, certificate, schedule, exhibit, letter or other document prepared or executed in connection with the Contemplated Transactions, including (a) any fees and expenses of legal counsel and accountants, the maximum amount of fees and expenses payable to financial advisors, investment bankers, brokers, consultants, tax advisors, transfer agents, proxy solicitor and other advisors of such Party; (b) 50% of the fees paid to the SEC in connection with filing the Registration Statement, the Proxy Statement, and any amendments and supplements thereto, with the SEC; (c) 50% of the fees and expenses in connection with the printing, mailing and distribution of the Registration Statement and any amendments and supplements thereto; (d) 50% of the Nasdaq Fees; (e) the CVR Fees; and (f) any bonus, retention payments, severance, change-in-control payments or similar payment obligations (including payments with “single-trigger” provisions triggered at and as of the consummation of the transactions contemplated hereby) that become due or payable to any director, officer, employee or consultant in connection with the consummation of the Contemplated Transactions, together with any payroll Taxes associated therewith; provided, that, Transaction Expenses shall not include any Costs associated with the obtainment of directors and officers insurance pursuant to Section 6.8.

“Treasury Regulations” means the United States Treasury regulations promulgated under the Code.

(b) Each of the following terms is defined in the Section set forth opposite such term:

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1.2 Other Definitional and Interpretative Provisions. The words “hereof,” “herein” and “hereunder” and words of like import used in this Agreement shall refer to this Agreement as a whole and not to any particular provision of this Agreement. The captions herein are included for convenience of reference only and shall be ignored in the construction or interpretation hereof. References to Sections, Exhibits and Schedules are to Sections, Exhibits and Schedules of this Agreement unless otherwise specified. Any capitalized terms used in any Exhibit or Schedule but not otherwise defined therein shall have the meaning as defined in this Agreement. Any singular term in this Agreement shall be deemed to include the plural, and any plural term the singular, the masculine gender shall include the feminine and neuter genders; the feminine gender shall include the masculine and neuter genders; and the neuter gender shall include masculine and feminine gender. Whenever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation,” whether or not they are in fact followed by those words or words of like import. The word “or” is not exclusive. “Writing,” “written” and comparable terms refer to printing, typing and other means of reproducing words (including electronic media) in a visible form. References to any agreement or Contract are to that agreement or Contract as amended, modified or supplemented from time to time in accordance with the terms hereof and thereof. References to any Person include the successors and permitted assigns of that Person. References to any statute are to that statute and to the rules and regulations promulgated thereunder, in each case as amended, modified, re-enacted thereof, substituted, from time to time. References to “$” and “dollars” are to the currency of the United States. All accounting terms used herein will be interpreted, and all accounting determinations hereunder will be made, in accordance with GAAP unless otherwise expressly specified. References from or through any date shall mean, unless otherwise specified, from and including or through and including, respectively. All references to “days” shall be to calendar days unless otherwise indicated as a “Business Day.” Except as otherwise specifically indicated, for purposes of measuring the beginning and ending of time periods in this Agreement (including for purposes of “Business Day” and for hours in a day or Business Day), the time at which a thing, occurrence or event shall begin or end shall be deemed to occur in the Eastern time zone of the United States. The Parties agree that any rule of construction to the effect that ambiguities are to be resolved against the drafting Party shall not be applied

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in the construction or interpretation of this Agreement. The Parties agree that the Company Disclosure Schedule or Magenta Disclosure Schedule shall be arranged in sections and subsections corresponding to the numbered and lettered sections and subsections contained in Section 3 or Section 4, respectively. The disclosures in any section or subsection of the Company Disclosure Schedule or the Magenta Disclosure Schedule shall qualify other sections and subsections in Section 3 or Section 4, respectively, to the extent it is readily apparent from a reading of the disclosure that such disclosure is applicable to such other sections and subsections. The words “delivered” or “made available” mean, with respect to any documentation, (a) that prior to 5:00 p.m. (New York City time) on the date that is the day prior to the date of this Agreement, a copy of such material has been posted to and made available by a Party to the other Party and its Representatives in the electronic data room maintained by such disclosing Party for the purposes of the Contemplated Transactions or (b) delivered by or on behalf of a Party or its Representatives to the other Party or its Representatives via electronic mail or in hard copy form prior to the execution of this Agreement.

Section 2. Description of Transaction

2.1 The Merger. Upon the terms and subject to the conditions set forth in this Agreement, at the Effective Time, Merger Sub shall be merged with and into the Company, and the separate existence of Merger Sub shall cease. The Company will continue as the surviving corporation in the Merger (the “Surviving Corporation”).

2.2 Effects of the Merger. The Merger shall have the effects set forth in this Agreement and in the applicable provisions of the DGCL. As a result of the Merger, the Company will become a wholly owned subsidiary of Magenta.

2.3 Closing; Effective Time. Unless this Agreement is earlier terminated pursuant to the provisions of Section 10.1, and subject to the satisfaction or waiver of the conditions set forth in Section 6, Section 7 and Section 8, the consummation of the Merger (the “Closing”) shall take place remotely, as promptly as practicable (but in no event later than the second Business Day following the satisfaction or waiver of the last to be satisfied or waived of the conditions set forth in Section 7, Section 8 and Section 9, other than those conditions that by their nature are to be satisfied at the Closing, but subject to the satisfaction or waiver of each of such conditions), or at such other time, date and place as Magenta and the Company may mutually agree in writing. The date on which the Closing actually takes place is referred to as the “Closing Date.” At the Closing, the Parties shall cause the Merger to be consummated by executing and filing with the Secretary of State of the State of Delaware a certificate of merger with respect to the Merger, satisfying the applicable requirements of the DGCL and in form and substance as agreed to by the Parties (the “Certificate of Merger”). The Merger shall become effective at the time of the filing of such Certificate of Merger with the Secretary of State of the State of Delaware or at such later time as may be specified in such Certificate of Merger with the consent of Magenta and the Company (the time as of which the Merger becomes effective being referred to as the “Effective Time”).

2.4 Organizational Documents; Directors and Officers.

(a) the certificate of incorporation of the Surviving Corporation shall be amended and restated in the Merger to read as set forth on Exhibit A to the Certificate of Merger, until thereafter amended as provided by the DGCL and such certificate of incorporation;

(b) the certificate of incorporation of Magenta shall be identical to the certificate of incorporation of Magenta immediately prior to the Effective Time, until thereafter amended as provided by the DGCL and such certificate of incorporation; provided, however, that at the Effective Time, Magenta shall file an amendment to its certificate of incorporation to (i) change the name of Magenta to “Dianthus Therapeutics, Inc.”, (ii) effect the Nasdaq Reverse Split (to the extent applicable and necessary) and (iii) make such other changes as are mutually agreeable to Magenta and the Company;

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(c) the bylaws of the Surviving Corporation shall be identical to the bylaws of Merger Sub as in effect immediately prior to the Effective Time, until thereafter amended as provided by the DGCL and such bylaws;

(d) the directors and officers of Magenta, each to hold office in accordance with the certificate of incorporation and bylaws of Magenta, shall be as set forth in Section 6.13; and

(e) the directors and officers of Surviving Corporation, each to hold office in accordance with the certificate of incorporation and bylaws of Merger Sub, shall be as set forth in Section 6.13 after giving effect to the provisions of Section 6.13, or such other persons as shall be mutually agreed upon by Magenta and the Company.

2.5 Conversion of Company Equity Securities.

(a) At the Effective Time, by virtue of the Merger and without any further action on the part of Magenta, Merger Sub, the Company or any stockholder of the Company or Magenta:

(i) any shares of Company Capital Stock held as treasury stock immediately prior to the Effective Time shall be canceled and retired and shall cease to exist, and no consideration shall be delivered in exchange therefor; and

(ii) subject to Section 2.5(c), each share of Company Capital Stock (including any shares of Company Capital Stock issued pursuant to any Company Pre-Closing Financing) outstanding immediately prior to the Effective Time (excluding shares to be canceled pursuant to Section 2.5(a)(i) and excluding Dissenting Shares) shall be converted solely into the right to receive a number of shares of Magenta Common Stock equal to the Exchange Ratio (the “Merger Consideration”).

(b) If any shares of Company Capital Stock outstanding immediately prior to the Effective Time are unvested or are subject to a repurchase option or a risk of forfeiture under any applicable restricted stock purchase agreement or other similar agreement with the Company, then the shares of Magenta Common Stock issued in exchange for such shares of Company Capital Stock will to the same extent be unvested and subject to the same repurchase option or risk of forfeiture, and such shares of Magenta Common Stock shall accordingly be marked with appropriate legends. The Company shall take all actions that may be necessary to ensure that, from and after the Effective Time, Magenta is entitled to exercise any such repurchase option or other right set forth in any such restricted stock purchase agreement or other agreement.

(c) No fractional shares of Magenta Common Stock shall be issued in connection with the Merger, and no certificates or scrip for any such fractional shares shall be issued. Any holder of Company Capital Stock who would otherwise be entitled to receive a fraction of a share of Magenta Common Stock (after aggregating all fractional shares of Magenta Common Stock issuable to such holder) shall receive from Magenta, in lieu of such fractional share and upon surrender by such holder of a letter of transmittal in accordance with Section 2.8 and any accompanying documents as required therein: (i) one share of Magenta Common Stock if the aggregate amount of fractional shares of Magenta Common Stock such holder of Company Capital Stock would otherwise be entitled to is equal to or exceeds 0.50; or (ii) no shares of Magenta Common Stock if the aggregate amount of fractional shares of Magenta Common Stock such holder of Company Capital Stock would otherwise be entitled to is less than 0.50, with no cash being paid for any fractional share eliminated by such rounding.

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(d) All Company Options outstanding immediately prior to the Effective Time shall be treated in accordance with Section 6.5(a). All Company Warrants outstanding immediately prior to the Effective Time shall be treated in accordance with Section 6.5(b).

(e) Each share of common stock, $0.001 par value per share, of Merger Sub issued and outstanding immediately prior to the Effective Time shall be converted into and exchanged for one validly issued, fully paid and nonassessable share of common stock, $0.001 par value per share, of the Surviving Corporation. Each book entry share of Merger Sub evidencing ownership of any such shares shall, as of the Effective Time, evidence ownership of such shares of common stock of the Surviving Corporation.

(f) If, between the date of this Agreement and the Effective Time, the outstanding Company Capital Stock or Magenta Common Stock shall have been changed into, or exchanged for, a different number of shares or a different class, by reason of any stock dividend, subdivision, reclassification, recapitalization, split (including the Nasdaq Reverse Split to the extent such split has not previously been taken into account in calculating the Exchange Ratio), combination or exchange of shares or other like change, the Exchange Ratio shall, to the extent necessary, be equitably adjusted to reflect such change to the extent necessary to provide the holders of Company Capital Stock, Company Options, Company Warrants and Magenta Common Stock with the same economic effect as contemplated by this Agreement prior to such stock dividend, subdivision, reclassification, recapitalization, split, combination or exchange of shares or other like change; provided, however, that nothing herein will be construed to permit the Company or Magenta to take any action with respect to Company Capital Stock or Magenta Common Stock, respectively, that is prohibited or not expressly permitted by the terms of this Agreement.

2.6 Contingent Value Right

(a) Prior to the Effective Time, Magenta shall declare a distribution (the “Closing Distribution”) to holders of Magenta Common Stock of record as of immediately prior to the Effective Time (including, for the avoidance of doubt, those shares of Magenta Common Stock issued upon settlement of Magenta Restricted Stock Units pursuant to Section 6.7) of the right to receive one contingent value right (each, a “CVR”) for each outstanding share of Magenta Common Stock held by such stockholder as of such date (less applicable withholding taxes), each representing the right to receive contingent payments upon the occurrence of certain events set forth in, and subject to and in accordance with the terms and conditions of, the Contingent Value Rights Agreement in the form attached hereto as Exhibit D (the “CVR Agreement”). The record date for the Closing Distribution shall be the close of business on the Business Day on which the Effective Time occurs and the payment date for which shall be three (3) Business Days after the Effective Time; provided that the payment of such distribution may be conditioned upon the occurrence of the Effective Time.

(b) Magenta and the Exchange Agent shall, at or prior to the Effective Time, duly authorize, execute and deliver the CVR Agreement, subject to any reasonable revisions to the CVR Agreement that are requested by such Exchange Agent and are reasonably acceptable to the Company and Magenta.

(c) Magenta shall pay all costs and fees associated with any action contemplated by this Section 2.6 (the “CVR Fees”).

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2.7 Closing of the Company’s Transfer Books. At the Effective Time: (a) all Company Capital Stock outstanding immediately prior to the Effective Time shall be treated in accordance with Section 2.5(a), and all holders of certificates representing Company Capital Stock that were outstanding immediately prior to the Effective Time shall cease to have any rights as stockholders of the Company and (b) the stock transfer books of the Company shall be closed with respect to all Company Capital Stock outstanding immediately prior to the Effective Time. No further transfer of any such Company Capital Stock shall be made on such stock transfer books after the Effective Time.

2.8 Surrender of Company Capital Stock.

(a) On or prior to the Closing Date, Magenta and the Company shall jointly select a reputable bank, transfer agent or trust company to act as exchange agent in the Merger (the “Exchange Agent”). At the Effective Time, Magenta shall deposit with the Exchange Agent evidence of book-entry shares representing the shares of Magenta Common Stock issuable pursuant to Section 2.5(a) in exchange for Company Capital Stock.

(b) Promptly after the Effective Time, the Parties shall cause the Exchange Agent to mail to the Persons who were record holders of shares of Company Capital Stock that were converted into the right to receive the Merger Consideration: (i) a letter of transmittal in customary form and containing such provisions as Magenta may reasonably specify (including a provision confirming that delivery of Company Stock Certificates shall be effected, and risk of loss and title to Company Stock Certificates shall pass, only upon delivery of such Company Stock Certificates to the Exchange Agent) and (ii) instructions for effecting the surrender of Company Stock Certificates, or uncertificated shares of Company Capital Stock, in exchange for book-entry shares of Magenta Common Stock. Upon surrender of a Company Stock Certificate or other reasonable evidence of the ownership of uncertificated Company Capital Stock to the Exchange Agent for exchange, together with a duly executed letter of transmittal and such other documents as may be reasonably required by the Exchange Agent or Magenta: (A) the holder of such Company Stock Certificate or uncertificated shares of Company Capital Stock shall be entitled to receive in exchange therefor book-entry shares representing the Merger Consideration (in a number of whole shares of Magenta Common Stock) that such holder has the right to receive pursuant to the provisions of Section 2.5(a) and (B) the Company Stock Certificate or uncertificated shares of Company Capital Stock so surrendered shall be canceled. Until surrendered as contemplated by this Section 2.8(b), each Company Stock Certificate or uncertificated shares of Company Capital Stock shall be deemed, from and after the Effective Time, to represent only the right to receive book-entry shares of Magenta Common Stock representing the Merger Consideration. If any Company Stock Certificate shall have been lost, stolen or destroyed, Magenta may, in its discretion and as a condition precedent to the delivery of any shares of Magenta Common Stock, require the owner of such lost, stolen or destroyed Company Stock Certificate to provide an applicable affidavit with respect to such Company Stock Certificate and post a bond indemnifying Magenta against any claim suffered by Magenta related to the lost, stolen or destroyed Company Stock Certificate or any Magenta Common Stock issued in exchange therefor as Magenta may reasonably request.

(c) No dividends or other distributions declared or made with respect to Magenta Common Stock with a record date after the Effective Time shall be paid to the holder of any unsurrendered Company Stock Certificate with respect to the shares of Magenta Common Stock that such holder has the right to receive in the Merger until such holder surrenders such Company Stock Certificate or uncertificated shares of Company Capital Stock or provides an affidavit of loss or destruction in lieu thereof in accordance with this Section 2.8 (at which time such holder shall be entitled, subject to the effect of applicable abandoned property, escheat or similar Laws, to receive all such dividends and distributions, without interest).

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(d) Any shares of Magenta Common Stock deposited with the Exchange Agent that remain undistributed to holders of Company Stock Certificates as of the date that is 180 days after the Closing Date shall be delivered to Magenta upon demand, and any holders of Company Stock Certificates who have not theretofore surrendered their Company Stock Certificates or uncertificated shares of Company Capital Stock in accordance with this Section 2.8 shall thereafter look only to Magenta for satisfaction of their claims for Magenta Common Stock and any dividends or distributions with respect to shares of Magenta Common Stock.

(e) No Party shall be liable to any holder of any Company Stock Certificate or uncertificated shares of Company Capital Stock or to any other Person with respect to any shares of Magenta Common Stock (or dividends or distributions with respect thereto) or for any cash amounts delivered to any public official pursuant to any applicable abandoned property Law, escheat Law or similar Law.

2.9 Calculation of Net Cash and Company Valuation.

(a) No later than five (5) Business Days before the Closing, Magenta will deliver to the Company a schedule (the “Magenta Net Cash Schedule”) setting forth, in reasonable detail, Magenta’s good faith, estimated calculation of Magenta Net Cash (the “Magenta Net Cash Calculation”) as of 11:59 p.m. on the last Business Day prior to the Anticipated Closing Date (the “Cash Determination Time”) prepared and certified by Magenta’s chief financial officer (or if there is no chief financial officer at such time, the principal financial and accounting officer for Magenta). Magenta shall make available to the Company (electronically to the greatest extent possible), as reasonably requested by the Company, the work papers and back-up materials used or useful in preparing the Magenta Net Cash Schedule and, if reasonably requested by the Company, Magenta’s accountants and counsel at reasonable times and upon reasonable notice. The Magenta Net Cash Calculation shall include Magenta’s determination, as of the Cash Determination Time, of the defined terms in Section 1.1(a) necessary to calculate the Exchange Ratio.

(b) No later than five (5) Business Days before the Closing, the Company will deliver to Magenta a schedule (the “Company Valuation Schedule”) setting forth, in reasonable detail, the Company’s good faith, estimated calculations of the components of the Company Valuation (the “Company Valuation Calculation”) and the date of delivery of such schedule being (the “Company Valuation Delivery Date”) as of 11:59 p.m. on the last Business Day prior to the Anticipated Closing Date (the “Company Valuation Determination Time”) prepared and certified by the Company’s chief financial officer (or if there is no chief financial officer at such time, the chief executive officer). The Company shall make available to Magenta, as reasonably requested by Magenta, the work papers and back-up materials used or useful in preparing the Company Valuation Schedule and, if reasonably requested by Magenta, the Company’s accountants and counsel at reasonable times and upon reasonable notice.

(c) No later than three (3) Business Days after the Cash Determination Time (the last day of such period, the “Response Date”), the Company shall have the right to dispute any part of the Magenta Net Cash Calculation by delivering a written notice to that effect to Magenta (a “Dispute Notice”). Any Dispute Notice shall identify in reasonable detail and to the extent known the nature and amounts of any proposed revisions to the Magenta Net Cash Calculation and will be accompanied by reasonably detailed materials supporting the basis for such revisions.

(d) No later than three (3) Business Days after the Company Valuation Delivery Date (the last day of such period, the “Company Valuation Response Date”), Magenta shall have the right to dispute any part of the Company Valuation Calculation by delivering a written notice to that effect to the Company (a “Company Valuation Dispute Notice”). Any Company Valuation Dispute Notice shall identify in reasonable detail and to the extent known the nature and amounts of any proposed revisions to the Company Valuation Calculation and will be accompanied by reasonably detailed materials supporting the basis for such revisions.

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(e) If, on or prior to the Response Date, the Company notifies Magenta in writing that it has no objections to the Magenta Net Cash Calculation or, if on the Response Date, the Company fails to deliver a Dispute Notice as provided in Section 2.9(c), then the Magenta Net Cash Calculation as set forth in the Magenta Net Cash Schedule shall be deemed to have been finally determined for purposes of this Agreement and to represent the Magenta Net Cash at the Cash Determination Time for purposes of this Agreement.

(f) If, on or prior to the Company Valuation Response Date, Magenta notifies the Company in writing that it has no objections to the Company Valuation Calculation or, if on the Company Valuation Response Date, Magenta fails to deliver a Company Valuation Dispute Notice as provided in Section 2.9(d), then the Company Valuation Calculation as set forth in the Company Valuation Schedule shall be deemed to have been finally determined for purposes of this Agreement and to represent the Company Valuation at the Company Valuation Determination Time for purposes of this Agreement.

(g) If the Company delivers a Dispute Notice on or prior to the Response Date, then Representatives of Magenta and the Company shall promptly meet and attempt in good faith to resolve the disputed item(s) and negotiate an agreed-upon determination of Magenta Net Cash, which agreed upon the Magenta Net Cash amount shall be deemed to have been finally determined for purposes of this Agreement and to represent the Magenta Net Cash at the Cash Determination Time for purposes of this Agreement.

(h) If Magenta delivers a Company Valuation Dispute Notice on or prior to the Company Valuation Response Date, then Representatives of Magenta and the Company shall promptly meet and attempt in good faith to resolve the disputed item(s) and negotiate an agreed-upon determination of the components of the Company Valuation, which agreed upon Company Valuation amount shall be deemed to have been finally determined for purposes of this Agreement and to represent the Company Valuation at the Company Valuation Determination Time for purposes of this Agreement.

(i) If Representatives of Magenta and the Company are unable to negotiate an agreed-upon determination of Magenta Net Cash as of the Cash Determination Time pursuant to Section 2.9(g) or the components of Company Valuation as of the Company Valuation Determination Time pursuant to Section 2.9(h) within three days after delivery of the Dispute Notice or the Company Valuation Dispute Notice, as applicable, (or such other period as Magenta and the Company may mutually agree upon), then any remaining disagreements as to the calculation of Magenta Net Cash or Company Valuation shall be referred to an independent auditor of recognized national standing jointly selected by Magenta and the Company. If the parties are unable to select an independent auditor within five (5) days, then either Magenta or the Company may thereafter request that the Boston, Massachusetts Office of the American Arbitration Association (“AAA”) make such selection (either the independent auditor jointly selected by both parties or such independent auditor selected by the AAA, the “Accounting Firm”). Magenta and the Company shall promptly deliver to the Accounting Firm the work papers and back-up materials used in preparing the Magenta Net Cash Schedule and the Dispute Notice and the Company Valuation Schedule and the Company Valuation Dispute Notice, and Magenta and the Company shall use commercially reasonable efforts to cause the Accounting Firm to make its determination within five (5) Business Days of accepting its selection. Magenta and the Company shall be afforded the opportunity to present to the Accounting Firm any material related to the unresolved disputes and to discuss the issues with the Accounting Firm; provided, however, that no such presentation or discussion shall occur without the presence of a Representative of each of Magenta and the Company. The determination of the Accounting

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Firm shall be limited to the disagreements submitted to the Accounting Firm. The determination of the amount of Magenta Net Cash or the components of the Company Valuation made by the Accounting Firm shall be made in writing delivered to each of Magenta and the Company, shall be final and binding on Magenta and the Company and shall (absent manifest error) be deemed to have been finally determined for purposes of this Agreement and to represent the Magenta Net Cash at the Cash Determination Time or the components of the Company Valuation at the Company Valuation Determination Time for purposes of this Agreement. The Parties shall delay the Closing until the resolution of the matters described in this Section 2.9(i). The fees and expenses of the Accounting Firm shall be allocated between Magenta and the Company in the same proportion that the disputed amount of the Magenta Net Cash or the Company Valuation that was unsuccessfully disputed by such Party (as finally determined by the Accounting Firm) bears to the total disputed amount of the Magenta Net Cash amount or the components of the Company Valuation. If this Section 2.9(i) applies as to the determination of the Magenta Net Cash at the Cash Determination Time or to the determination of the components of the Company Valuation at the Company Valuation Determination Time, as applicable, upon resolution of the matter in accordance with this Section 2.9(i), the Parties shall not be required to determine Magenta Net Cash or the Company Valuation again even though the Closing may occur later than the Anticipated Closing Date, except that either Magenta and the Company may request a redetermination of Magenta Net Cash or the Company Valuation if the Closing Date is more than thirty (30) days after the Anticipated Closing Date.

2.10 Further Action. If, at any time after the Effective Time, any further action is determined by the Surviving Corporation to be necessary or desirable to carry out the purposes of this Agreement or to vest the Surviving Corporation with full right, title and possession of and to all rights and property of the Company, then the officers and directors of the Surviving Corporation shall be fully authorized, and shall use their and its commercially reasonable efforts (in the name of the Company, in the name of Merger Sub, in the name of the Surviving Corporation and otherwise) to take such action.

2.11 Intended Tax Treatment. The Parties acknowledge and agree that, for U.S. federal (and applicable state and local) income Tax purposes, the Merger is intended to qualify as a reorganization within the meaning of Section 368(a) of the Code (the “Intended Tax Treatment”). The Parties adopt this Agreement as a “plan of reorganization” within the meaning of Treasury Regulations Sections 1.368-2(g) and 1.368-3.

2.12 Withholding. Each of the Exchange Agent, Magenta and the Surviving Corporation shall be entitled to deduct and withhold from any consideration deliverable pursuant to this Agreement (including the Closing Distribution) to any Person such amounts as are required to be deducted or withheld from such consideration under applicable Law; provided that the Exchange Agent, Magenta and the Surviving Corporation shall use commercially reasonable efforts to promptly notify such Persons of any intention to withhold any portion of such consideration and cooperate with such Persons to reduce or eliminate any such withholding to the extent permitted by applicable Law. To the extent such amounts are so deducted or withheld and remitted to the appropriate Governmental Authority, such amounts shall be treated for all purposes under this Agreement as having been paid to the Person to whom such amounts would otherwise have been paid. All payments made under this agreement that constitute compensation to employees for services for Tax purposes shall be made through the payroll of the Surviving Corporation or Magenta, as applicable.

2.13 Appraisal Rights.

(a) Notwithstanding any provision of this Agreement to the contrary, shares of Company Capital Stock that are outstanding immediately prior to the Effective Time and which are held by stockholders who have exercised and perfected appraisal rights for such shares of Company Capital Stock in accordance with the DGCL (collectively, the “Dissenting Shares”) shall not be converted into or

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represent the right to receive the Merger Consideration described in Section 2.5 attributable to such Dissenting Shares. Such stockholders shall be entitled to receive payment of the appraised value of such shares of Company Capital Stock held by them in accordance with the DGCL, unless and until such stockholders fail to perfect or effectively withdraw or otherwise lose their appraisal rights under the DGCL. All Dissenting Shares held by stockholders who shall have failed to perfect or shall have effectively withdrawn or lost their right to appraisal of such shares of Company Capital Stock under the DGCL (whether occurring before, at or after the Effective Time) shall thereupon be deemed to be converted into and to have become exchangeable for, as of the Effective Time, the right to receive the Merger Consideration, without interest, attributable to such Dissenting Shares upon their surrender in the manner provided in Sections 2.5 and 2.8.

(b) The Company shall give Magenta prompt written notice of any demands by dissenting stockholders received by the Company, withdrawals of such demands and any other instruments served on the Company and any material correspondence received by the Company in connection with such demands, and Magenta shall have the right to participate in all negotiations and proceedings with respect to such demands. The Company shall not, except with Magenta’s prior written consent, not to be unreasonably withheld, delayed or conditioned, make any payment with respect to, or settle or offer to settle, any such demands, or approve any withdrawal of any such demands or agree to do any of the foregoing.

Section 3. Representations and Warranties of the Company.

Subject to Section 3, except as set forth in the written disclosure schedule delivered by the Company to Magenta (the “Company Disclosure Schedule”), the Company represents and warrants to Magenta and Merger Sub as follows:

3.1 Due Organization; Subsidiaries.

(a) The Company is a corporation or other legal entity duly incorporated or otherwise organized, validly existing and in good standing under the Laws of the jurisdiction of its incorporation or organization and has all necessary power and authority: (i) to conduct its business in the manner in which its business is currently being conducted, (ii) to own or lease and use its property and assets in the manner in which its property and assets are currently owned or leased and used and (iii) to perform its obligations under all Contracts by which it is bound.

(b) The Company is duly licensed and qualified to do business, and is in good standing (to the extent applicable in such jurisdiction), under the Laws of all jurisdictions where the nature of its business in the manner in which its business is currently being conducted requires such licensing or qualification other than in jurisdictions where the failure to be so qualified individually or in the aggregate would not be reasonably expected to have a Company Material Adverse Effect.

(c) The Company has no Subsidiaries and the Company does not own any capital stock or membership interests of, or any equity, ownership or profit sharing interest of any nature in, or controls directly or indirectly, any other Entity. The Company is not and has never otherwise been, directly or indirectly, a party to, member of or participant in any partnership, joint venture or similar business entity. The Company has not agreed or is obligated to make, or is bound by any Contract under which it may become obligated to make, any future investment in or capital contribution to any other Entity. The Company has not, at any time, been a general partner of, or has otherwise been liable for any of the debts or other obligations of, any general partnership, limited partnership or other Entity.

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3.2 Organizational Documents. The Company has delivered to Magenta accurate and complete copies of the Organizational Documents of the Company. The Company is not in breach or violation of its Organizational Documents in any material respect.

3.3 Authority; Binding Nature of Agreement. The Company has all necessary corporate power and authority to enter into and to perform its obligations under this Agreement and to consummate the Contemplated Transactions. The Company Board has (i) determined that the Contemplated Transactions are fair to, advisable and in the best interests of the Company and its stockholders, (ii) approved and declared advisable this Agreement and the Contemplated Transactions and (iii) determined to recommend, upon the terms and subject to the conditions set forth in this Agreement, that the stockholders of the Company vote to adopt this Agreement and thereby approve the Contemplated Transactions. This Agreement has been duly executed and delivered by the Company and assuming the due authorization, execution and delivery by Magenta and Merger Sub, constitutes the legal, valid and binding obligation of the Company, enforceable against the Company in accordance with its terms, subject to the Enforceability Exceptions.

3.4 Vote Required. The affirmative vote (or written consent) of (i) the holders of a majority of the shares of Company Capital Stock each outstanding on the record date and entitled to vote thereon, voting as a single class on an as-converted basis, (ii) the holders of 55% of the shares of Company Preferred Stock outstanding on the record date and entitled to vote thereon, voting as a separate class on an as-converted basis, and (iii) the holders of a majority of the shares of Company Series A Preferred Stock outstanding on the record date and entitled to vote thereon, voting as a separate class, is the only vote of the holders of any class or series of Company Capital Stock necessary to adopt and approve this Agreement and approve the Contemplated Transactions (collectively, the “Required Company Stockholder Vote”).

3.5 Non-Contravention; Consents.

(a) Subject to obtaining the Required Company Stockholder Vote and the filing of the Certificate of Merger required by the DGCL, neither (x) the execution, delivery or performance of this Agreement by the Company, nor (y) the consummation of the Contemplated Transactions, will directly or indirectly (with or without notice or lapse of time):

(i) contravene, conflict with or result in a violation of any of the provisions of the Company’s Organizational Documents;

(ii) contravene, conflict with or result in a material violation of, or give any Governmental Authority or other Person the right to challenge the Contemplated Transactions or to exercise any remedy or obtain any relief under, any Law or any Order by which the Company, or any of the assets owned or used by the Company, is subject;

(iii) contravene, conflict with or result in a material violation of any of the terms or requirements of, or give any Governmental Authority the right to revoke, withdraw, suspend, cancel, terminate or modify, any Governmental Authorization that is held by the Company;

(iv) contravene, conflict with or result in a violation or breach of, or result in a default under, any provision of any Company Material Contract, or give any Person the right to: (A) declare a default or exercise any remedy under any Company Material Contract, (B) any material payment, rebate, chargeback, penalty or change in delivery schedule under any Company Material Contract, (C) accelerate the maturity or performance of any Company Material Contract or (D) cancel, terminate or modify any term of any Company Material Contract, except in the case of any nonmaterial breach, default, penalty or modification; or

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(v) result in the imposition or creation of any Encumbrance upon or with respect to any asset owned or used by the Company (except for Permitted Encumbrances).

(b) Except for (i) the Required Company Stockholder Vote, (ii) the filing of the Certificate of Merger with the Secretary of State of the State of Delaware pursuant to the DGCL, and (iii) such consents, waivers, approvals, orders, authorizations, registrations, declarations and filings as may be required under applicable federal and state securities laws, the Company was not, is not, nor will be required to make any filing with or give any notice to, or to obtain any Consent from, any Person in connection with (x) the execution, delivery or performance of this Agreement or (y) the consummation of the Contemplated Transactions.

(c) The Company Board has taken and will take all actions necessary to ensure that the restrictions applicable to business combinations contained in Section 203 of the DGCL, to the extent applicable to the Company, are, and will be, inapplicable to the execution, delivery and performance of this Agreement and the Company Stockholder Support Agreements and to the consummation of the Contemplated Transactions. No other state takeover statute or similar Law applies or purports to apply to the Merger, this Agreement, the Company Stockholder Support Agreements or any of the Contemplated Transactions.

3.6 Capitalization.

(a) Section 3.6(a) of the Company Disclosure Schedule sets forth an accurate and complete capitalization table of the Company as of the date of this Agreement.

(b) All of the outstanding Company Capital Stock as set out in Section 3.6(a) of the Company Disclosure Schedule have been duly authorized and validly issued, and are fully paid and nonassessable and are free of any Encumbrances other than Encumbrances set forth in the Organizational Documents or under applicable securities Laws. None of the outstanding Company Capital Stock is entitled or subject to any preemptive right, right of participation, right of maintenance or any similar right and none of the outstanding Company Capital Stock is subject to any right of first refusal in favor of the Company. Except as contemplated herein, there is no Company Contract relating to the voting or registration of, or restricting any Person from purchasing, selling, pledging or otherwise disposing of (or granting any option or similar right with respect to), any Company Capital Stock. The Company is not under any obligation, nor is it bound by any Contract pursuant to which it may become obligated, to repurchase, redeem or otherwise acquire any outstanding Company Capital Stock or other securities. Section 3.6(b) of the Company Disclosure Schedule accurately and completely lists all repurchase rights held by the Company with respect to Company Capital Stock (including shares issued pursuant to the exercise of options) and specifies which of those repurchase rights are currently exercisable.

(c) Except as set forth on Section 3.6(c) of the Company Disclosure Schedule, the Company does not have any option plan or any other plan, program, agreement or arrangement providing for an equity-based compensation for any Person.

(d) Except as set forth on Section 3.6(d) of the Company Disclosure Schedule, there is no: (i) outstanding subscription, option, call, warrant or right (whether or not currently exercisable) to acquire any Company Capital Stock or other securities of the Company, (ii) outstanding security, instrument or obligation that is or may become convertible into or exchangeable for any shares of the capital stock or other securities of the Company, (iii) stockholder rights plan (or similar plan commonly referred

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to as a “poison pill”) or Contract under which the Company is or may become obligated to sell or otherwise issue any Company Capital Stock or any other securities or (iv) condition or circumstance that could be reasonably likely to give rise to or provide a basis for the assertion of a claim by any Person to the effect that such Person is entitled to acquire or receive any shares of capital stock or other securities of the Company. There are no outstanding or authorized stock appreciation, phantom stock, profit participation or other similar rights with respect to the Company.

(e) All outstanding Company Capital Stock and other securities of the Company have been issued and granted in material compliance with (i) all applicable securities laws and other applicable Law and (ii) all requirements set forth in applicable Contracts.

(f) The Company Capital Stock are uncertificated.

3.7 Financial Statements.

(a) Section 3.7(a) of the Company Disclosure Schedule includes true and complete copies of the Company’s unaudited balance sheets at December 31, 2022 (the “Company Balance Sheet”), together with related unaudited statements of operations, changes in stockholders’ equity and cash flows, and notes thereto, of the Company for the fiscal year then ended (collectively, the “Company Financials”). The Company Financials (A) were prepared in accordance with United States generally accepted accounting principles (“GAAP”) (except that the Company Financials may not have notes thereto and other presentation items that may be required by GAAP and are subject to normal and recurring year-end adjustments that are not reasonably expected to be material in amount) applied on a consistent basis unless otherwise noted therein throughout the periods indicated and (B) fairly present, in all material respects, the financial position and operating results of the Company as of the dates and for the periods indicated therein.

(b) The Company maintains a system of internal accounting controls designed to provide reasonable assurance that: (i) transactions are executed in accordance with management’s general or specific authorizations, (ii) transactions are recorded as necessary to permit preparation of the financial statements of the Company in conformity with GAAP and to maintain accountability of the Company’s assets, (iii) access to the Company’s assets is permitted only in accordance with management’s general or specific authorization and (iv) the recorded accountability for the Company’s assets is compared with the existing assets at regular intervals and appropriate action is taken with respect to any differences. The Company maintains internal controls consistent with the practices of similarly situated private companies over financial reporting that provides reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes.

(c) Section 3.7(c) of the Company Disclosure Schedule lists, and the Company has delivered to Magenta accurate and complete copies of the documentation creating or governing, all securitization transactions and “off-balance sheet arrangements” (as defined in Item 303(c) of Regulation S-K under the Exchange Act) effected by the Company.

(d) There have been no formal internal investigations regarding financial reporting or accounting policies and practices discussed with, reviewed by or initiated at the direction of the chief executive officer, chief financial officer or general counsel of the Company, the Company Board or any committee thereof. Neither the Company nor its independent auditors have identified (i) any significant deficiency or material weakness in the design or operation of the system of internal accounting controls utilized by the Company, (ii) any fraud, whether or not material, that involves the Company, the Company’s management or other employees who have a role in the preparation of financial statements or the internal accounting controls utilized by the Company or (iii) any claim or allegation regarding any of the foregoing.

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3.8 Absence of Changes. Except as set forth on Section 3.8 of the Company Disclosure Schedule, between December 31, 2022 and the date of this Agreement, the Company has conducted its business only in the Ordinary Course of Business (except for the execution and performance of this Agreement and the discussions, negotiations and transactions related thereto) and there has not been any (a) Company Material Adverse Effect or (b) action, event or occurrence that would have required consent of Magenta pursuant to Section 5.2(b) of this Agreement had such action, event or occurrence taken place after the execution and delivery of this Agreement.

3.9 Absence of Undisclosed Liabilities. Since December 31, 2022, the Company does not have any liability, indebtedness, obligation, expense, claim, deficiency, guaranty or endorsement of any kind, whether accrued, absolute, contingent, matured, unmatured or otherwise (each a “Liability”), in each case, of a type required to be reflected or reserved for on a balance sheet prepared in accordance with GAAP, except for: (a) Liabilities disclosed, reflected or reserved against in the Company Balance Sheet, (b) normal and recurring current Liabilities that have been incurred by the Company since the date of the Company Balance Sheet in the Ordinary Course of Business (none of which relates to any breach of contract, breach of warranty, tort, infringement or violation of Law), (c) Liabilities for performance of obligations of the Company under Company Contracts, (d) Liabilities incurred in connection with the Contemplated Transactions and the Subscription Agreement and (e) Liabilities listed in Section 3.9 of the Company Disclosure Schedule.

3.10 Title to Assets. The Company has good and valid title to, or, in the case of leased properties and assets, valid leasehold interests in, all tangible properties or tangible assets and equipment used or held for use in its business or operations or purported to be owned by it, including: (a) all tangible assets reflected on the Company Balance Sheet and (b) all other tangible assets reflected in the books and records of the Company as being owned by the Company. All of such assets are owned or, in the case of leased assets, leased by the Company free and clear of any Encumbrances, other than Permitted Encumbrances.

3.11 Real Property; Leasehold. The Company does not own and has never owned any real property. The Company has made available to Magenta (a) an accurate and complete list of all real properties with respect to which the Company directly or indirectly holds a valid leasehold interest as well as any other real estate that is in the possession of or leased by the Company and (b) copies of all leases under which any such real property is possessed (the “Company Real Estate Leases”), each of which is in full force and effect, with no existing material default thereunder.

3.12 Intellectual Property.

(a) Section 3.12(a) of the Company Disclosure Schedule is an accurate, true and complete listing of all Company Registered IP.

(b) Section 3.12(b) of the Company Disclosure Schedule accurately identifies (i) all Company Contracts pursuant to which any Company IP Rights are licensed to the Company (other than (A) any non-customized software that (1) is so licensed solely in executable or object code form pursuant to a nonexclusive, internal use software license and other Intellectual Property associated with such software and (2) is not incorporated into, or material to the development, manufacturing or distribution of, any of the Company’s products or services, (B) any Intellectual Property licensed on a nonexclusive basis ancillary to the purchase or use of equipment, reagents or other materials, (C) any confidential information provided under confidentiality agreements and (D) agreements between Company and its

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employees in Company’s standard form thereof), (ii) the corresponding Company Contract pursuant to which such Company IP Rights are licensed to the Company and (iii) whether the license or licenses granted to the Company are exclusive or nonexclusive.

(c) Section 3.12(c) of the Company Disclosure Schedule accurately identifies each Company Contract pursuant to which any Person has been granted any license or covenant not to sue under, or otherwise has received or acquired any right (whether or not currently exercisable) or interest in, any Company IP Rights (other than (i) any confidential information provided under confidentiality agreements and (ii) any Company IP Rights nonexclusively licensed to academic collaborators, suppliers or service providers for the sole purpose of enabling such academic collaborator, supplier or service providers to provide services for the Company’s benefit).

(d) The Company is not bound by, and no Company IP Rights are subject to, any Contract containing any covenant or other provision that in any way limits or restricts the ability of the Company to use, exploit, assert or enforce any Company IP Rights anywhere in the world.

(e) The Company exclusively owns all right, title and interest to and in Company IP Rights (other than (i) Company IP Rights licensed to the Company, or co-owned rights each as identified in Section 3.12(e) of the Company Disclosure Schedule, (ii) any non-customized software that (A) is licensed to the Company solely in executable or object code form pursuant to a nonexclusive, internal use software license and other Intellectual Property associated with such software and (B) is not incorporated into, or material to the development, manufacturing or distribution of, any of the Company’s products or services and (iii) any Intellectual Property licensed on a nonexclusive basis ancillary to the purchase or use of equipment, reagents or other materials), in each case, free and clear of any Encumbrances (other than Permitted Encumbrances). Without limiting the generality of the foregoing:

(i) All documents and instruments necessary to register or apply for or renew registration of Company Registered IP have been validly executed, delivered and filed in a timely manner with the appropriate Governmental Authority.

(ii) Each Person who is or was an employee or contractor of the Company and who is or was involved in the creation or development of any Intellectual Property for the Company has signed a valid, enforceable agreement containing a present assignment of such Intellectual Property to the Company and confidentiality provisions protecting trade secrets and confidential information of the Company.

(iii) To the Knowledge of the Company, no current or former stockholder, officer, director or employee of the Company has any claim, right (whether or not currently exercisable) or interest to or in any Company IP Rights purported to be owned by the Company. To the Knowledge of the Company, no employee of the Company is (a) bound by or otherwise subject to any Contract restricting him or her from performing his or her duties for the Company or (b) in breach of any Contract with any former employer or other Person concerning Company IP Rights purported to be owned by the Company or confidentiality provisions protecting trade secrets and confidential information comprising Company IP Rights purported to be owned by the Company.

(iv) No funding, facilities or personnel of any Governmental Authority were used, directly or indirectly, to develop or create, in whole or in part, any Company IP Rights in which the Company has an ownership interest.

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(v) The Company has taken reasonable steps to maintain the confidentiality of and otherwise protect and enforce its rights in all proprietary information that the Company holds, or purports to hold, as confidential or a trade secret.

(vi) The Company has not assigned or otherwise transferred ownership of, or agreed to assign or otherwise transfer ownership of, any Company IP Rights to any other Person.

(f) The Company has delivered or made available to Magenta, a complete and accurate copy of all Company IP Rights Agreements. With respect to each of the Company IP Rights Agreements: (i) each such agreement is valid and binding on the Company and in full force and effect, (ii) the Company has not received any written notice of termination or cancellation under such agreement, or received any written notice of breach or default under such agreement, which breach has not been cured or waived and (iii) the Company, and to the Knowledge of the Company, no other party to any such agreement, is not in breach or default thereof in any material respect.

(g) The manufacture, marketing, sale, offering for sale, importation, use or intended use or other disposal of any product as currently sold or under development by the Company does not violate any license or agreement between the Company and any other third party, and, to the Knowledge of the Company, does not infringe or misappropriate any valid and issued Patent right or other Intellectual Property of any other Person, which infringement or misappropriation would reasonably be expected to have a Company Material Adverse Effect. To the Knowledge of the Company, no third party is infringing upon any Patents owned by Company within the Company IP Rights, or otherwise violating any Company IP Rights Agreement.

(h) As of the date of this Agreement, Company is not a party to any Legal Proceeding (including, but not limited to, opposition, interference or other proceeding in any patent or other government office) contesting the validity, enforceability, claim construction, ownership or right to use, sell, offer for sale, license or dispose of any Company IP Rights. The Company has not received any written notice asserting that any Company IP Rights or the proposed use, sale, offer for sale, license or disposition of products, methods or processes claimed or covered thereunder infringes or misappropriates or violates the rights of any other Person or that the Company has otherwise infringed, misappropriated or otherwise violated any Intellectual Property of any Person. None of the Company IP Rights is subject to any outstanding order of, judgment of, decree of or agreement with any Governmental Authority that limits the ability of the Company to exploit any Company IP Rights.

(i) Each item of Company Registered IP is and at all times has been filed and maintained in compliance in all material respects with all applicable Law and all filings, payments and other actions required to be made or taken to maintain such item of Company Registered IP in full force and effect have been made by the applicable deadline. To the Knowledge of the Company, all Company Registered IP that is issued or granted is valid and enforceable.

(j) To the Knowledge of the Company, no trademark (whether registered or unregistered) or trade name owned, used or applied for by the Company conflicts or interferes with any trademark (whether registered or unregistered) or trade name owned, used or applied for by any other Person. None of the goodwill associated with or inherent in any trademark (whether registered or unregistered) in which the Company has or purports to have an ownership interest has been impaired as determined by the Company in accordance with GAAP.

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(k) Except as set forth in Sections 3.12(b) or 3.12(c) of the Company Disclosure Schedule or as contained in license, distribution or service agreements entered into in the Ordinary Course of Business by the Company (i) the Company is not bound by any Contract to indemnify, defend, hold harmless or reimburse any other Person with respect to any Intellectual Property infringement, misappropriation, or similar claim which is material to the Company, taken as a whole and (ii) the Company has never assumed, or agreed to discharge or otherwise take responsibility for, any existing or potential liability of another Person for infringement, misappropriation, or violation of any Intellectual Property right, which assumption, agreement or responsibility remains in force as of the date of this Agreement.

(l) The Company is not party to any Contract that, as a result of such execution, delivery and performance of this Agreement, will cause the grant of any license or other right to any Company IP Rights, result in breach of, default under or termination of such Contract with respect to any Company IP Rights, or impair the right of the Company or the Surviving Corporation and its Subsidiaries to use, sell or license or enforce any Company IP Rights or portion thereof, except for the occurrence of any such grant or impairment that would not individually or in the aggregate, reasonably be expected to result in a Company Material Adverse Effect.

3.13 Agreements, Contracts and Commitments.

(a) Section 3.13(a) of the Company Disclosure Schedule lists the following Company Contracts in effect as of the date of this Agreement other than the Subscription Agreement (each, a “Company Material Contract” and collectively, the “Company Material Contracts”):

(i) each Company Contract relating to any agreement of indemnification or guaranty not entered into in the Ordinary Course of Business;

(ii) each Company Contract containing (A) any covenant limiting the freedom of the Company or the Surviving Corporation to engage in any line of business or compete with any Person, or limiting the development, manufacture or distribution of the Company’s products or services (B) any most-favored pricing arrangement, (C) any exclusivity provision or (D) any non-solicitation provision;

(iii) each Company Contract (A) pursuant to which any Person granted the Company an exclusive license under any Intellectual Property, or (B) pursuant to which the Company granted any Person an exclusive license under any Company IP Rights;

(iv) each Company Contract relating to capital expenditures and requiring payments after the date of this Agreement in excess of $100,000 pursuant to its express terms and not cancelable without penalty;

(v) each Company Contract relating to the disposition or acquisition of material assets or any ownership interest in any Entity;

(vi) each Company Contract relating to any mortgages, indentures, loans, notes or credit agreements, security agreements or other agreements or instruments relating to the borrowing of money or extension of credit in excess of $100,000 or creating any material Encumbrances with respect to any assets of the Company or any loans or debt obligations with officers or directors of the Company;

(vii) each Company Contract requiring payment by or to the Company after the date of this Agreement in excess of $500,000 pursuant to its express terms relating to: (A) any distribution agreement (identifying any that contain exclusivity provisions), (B) any agreement involving provision of services or products with respect to any pre-clinical or clinical

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development activities of the Company, (C) any dealer, distributor, joint marketing, alliance, joint venture, cooperation, development or other agreement currently in force under which the Company has continuing obligations to develop or market any product, technology or service, or any agreement pursuant to which the Company has continuing obligations to develop any Intellectual Property that will not be owned, in whole or in part, by the Company or (D) any Contract to license any patent, trademark registration, service mark registration, trade name or copyright registration to or from any third party to manufacture or produce any product, service or technology of the Company or any Contract to sell, distribute or commercialize any products or service of the Company, in each case, except for Company Contracts entered into in the Ordinary Course of Business;

(viii) each Company Contract with any Person, including any financial advisor, broker, finder, investment banker or other Person, providing advisory services to the Company in connection with the Contemplated Transactions;

(ix) each Company Contract to which the Company is a party or by which any of its assets and properties is currently bound, which involves annual obligations of payment by, or annual payments to, the Company in excess of $100,000; or

(x) any other Company Contract that is not terminable at will (with no penalty or payment) by the Company, and (A) which involves payment or receipt by the Company after the date of this Agreement under any such agreement, contract or commitment of more than $100,000 in the aggregate, or obligations after the date of this Agreement in excess of $100,000 in the aggregate or (B) that is material to the business or operations of the Company taken as a whole.

(b) The Company has delivered or made available to Magenta accurate and complete copies of all Company Material Contracts, including all amendments thereto. There are no Company Material Contracts that are not in written form. The Company has not, nor to the Company’s Knowledge, as of the date of this Agreement has any other party to a Company Material Contract, breached, violated or defaulted under, or received notice that it breached, violated or defaulted under, any of the terms or conditions of any Company Material Contract in such manner as would permit any other party to cancel or terminate any such Company Material Contract, or would permit any other party to seek damages which would reasonably be expected to have a Company Material Adverse Effect. As to the Company, as of the date of this Agreement, each Company Material Contract is valid, binding, enforceable and in full force and effect, subject to the Enforceability Exceptions. No Person is renegotiating, or has a right pursuant to the terms of any Company Material Contract to change, any material amount paid or payable to the Company under any Company Material Contract or any other material term or provision of any Company Material Contract.

3.14 Compliance; Permits; Restrictions.

(a) The Company is, and has been in material compliance with all applicable Laws. No investigation, claim, suit, proceeding, audit, Order or other Legal Proceeding or action by any Governmental Authority is pending or, to the Knowledge of the Company, threatened against the Company. There is no agreement or Order binding upon the Company which (i) has or would reasonably be expected to have the effect of prohibiting or materially impairing any business practice of the Company, any acquisition of material property by the Company or the conduct of business by the Company as currently conducted, (ii) is reasonably likely to have an adverse effect on the Company’s ability to comply with or perform any covenant or obligation under this Agreement or (iii) is reasonably likely to have the effect of preventing, delaying, making illegal or otherwise interfering with the Contemplated Transactions.

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(b) Except for matters regarding the U.S. Food and Drug Administration (or any successor agency thereto) (“FDA”) or other comparable Governmental Authority responsible for regulation of the development, testing, manufacturing, processing, storage, labeling, sale, marketing, advertising, distribution and importation or exportation of drug or medical device products (“Drug/Device Regulatory Agency”), the Company holds all required Governmental Authorizations for the operation of the business of the Company as currently conducted (the “Company Permits”). Section 3.14(b) of the Company Disclosure Schedule identifies each Company Permit. The Company is in material compliance with the terms of the Company Permits. No Legal Proceeding is pending or, to the Knowledge of the Company, threatened, which seeks to revoke, substantially limit, suspend or materially modify any Company Permit. The rights and benefits of each Company Permit will be available to the Surviving Corporation or its Subsidiaries, as applicable, immediately after the Effective Time on terms substantially identical to those enjoyed by the Company as of the date of this Agreement and immediately prior to the Effective Time.

(c) There are no Legal Proceedings pending or, to the Knowledge of the Company, threatened with respect to an alleged violation by the Company of the Federal Food, Drug, and Cosmetic Act (“FDCA”), the Public Health Service Act (“PHSA”), FDA regulations adopted thereunder, the Controlled Substances Act or any other similar Law promulgated by a Drug/Device Regulatory Agency.

(d) The Company holds all required Governmental Authorizations issuable by any Drug/Device Regulatory Agency necessary for the conduct of the business of the Company as currently conducted, and the development, testing, manufacturing, processing, storage, labeling, sale, marketing, advertising, distribution and importation or exportation, as currently conducted, of any of its products or product candidates (the “Company Product Candidates”) (collectively, the “Company Regulatory Permits”) and no such Company Regulatory Permit has been (i) revoked, withdrawn, suspended, cancelled or terminated or (ii) modified in any adverse manner, other than immaterial adverse modifications. Section 3.14(d) of the Company Disclosure Schedule identifies each Company Regulatory Permit. The Company has timely maintained and is in compliance in all material respects with the Company Regulatory Permits and has not received any written notice or correspondence or, to the Knowledge of the Company, other communication from any Drug/Device Regulatory Agency regarding (A) any material violation of or failure to comply materially with any term or requirement of any Company Regulatory Permit or (B) any revocation, withdrawal, suspension, cancellation, termination or material modification of any Company Regulatory Permit. The Company has made available to Magenta all information requested by Magenta in the Company’s possession or control relating to material Company Product Candidates and the development, testing, manufacturing, processing, storage, labeling, sale, marketing, advertising, distribution and importation or exportation of the Company Product Candidates, including but not limited to complete copies of the following (to the extent there are any): (x) adverse event reports; preclinical, clinical and other study reports and material study data; inspection reports, notices of adverse findings, untitled letters, warning letters, filings and letters and other written correspondence to and from any Drug/Device Regulatory Agency; and meeting minutes with any Drug/Device Regulatory Agency and (y) similar reports, material study data, notices, letters, filings, correspondence and meeting minutes with any other Governmental Authority. All such information is accurate and complete in all material respects.

(e) All clinical, preclinical and other studies and tests conducted by or on behalf of, or sponsored by, the Company, or in which the Company or its current products or product candidates, including the Company Product Candidates, have participated, were, and, if still pending, are being conducted in accordance in all material respects with standard medical and scientific research procedures, in accordance in all material respects with the applicable protocols and in compliance in all material respects with the applicable regulations of the Drug/Device Regulatory Agencies and other applicable Law, including 21 C.F.R. Parts 11, 50, 54, 56, 58, 312 and 812. The Company has not received any written notices, correspondence or other communications from any Drug/Device Regulatory Agency,

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Governmental Authority, institutional review board, ethics committee or safety monitoring committee requiring, or to the Knowledge of the Company threatening to initiate, any action to place a clinical hold order on, or otherwise terminate, delay or suspend any clinical studies conducted by or on behalf of, or sponsored by, the Company or in which the Company or its current products or product candidates, including the Company Product Candidates, have participated. Further, no clinical investigator, researcher or clinical staff participating in any clinical study conducted by or, to the Knowledge of the Company, on behalf of the Company has been disqualified from participating in studies involving the Company Product Candidates, and to the Knowledge of the Company, no such administrative action to disqualify such clinical investigators, researchers or clinical staff has been threatened or is pending.

(f) The Company is not, and to the Knowledge of the Company, no contract manufacturer with respect to any Company Product Candidate, is the subject of any pending or, to the Knowledge of the Company, threatened investigation in respect of its business or products, including Company Product Candidates, by the FDA pursuant to its “Fraud, Untrue Statements of Material Facts, Bribery, and Illegal Gratuities” Final Policy set forth in 56 Fed. Reg. 46191 (September 10, 1991) and any amendments thereto or by any other Drug/Device Regulatory Agency under a comparable policy. The Company has not, and to the Knowledge of the Company, no contract manufacturer, nor their respective officers, employees or agents, with respect to any Company Product Candidate has committed any acts, made any statement or failed to make any statement, in each case in respect of its business or products that would violate the FDA’s “Fraud, Untrue Statements of Material Facts, Bribery, and Illegal Gratuities” Final Policy, and any amendments thereto or a comparable policy of any other Drug/Device Regulatory Agency. None of the Company, and to the Knowledge of the Company, any contract manufacturer with respect to any Company Product Candidate, or any of their respective officers, employees or agents is currently or has been debarred, convicted of any crime or is engaging or has engaged in any conduct that could result in a debarment or exclusion under (i) 21 U.S.C. Section 335a or (ii) any similar applicable Law. To the Knowledge of the Company, no debarment or exclusionary claims, actions, proceedings or investigations in respect of their business or products are pending or threatened against the Company, and to the Knowledge of the Company, any contract manufacturer with respect to any Company Product Candidate, or any of their respective officers, employees or agents.

(g) All manufacturing operations conducted by, or to the Knowledge of the Company, for the benefit of the Company in connection with any Company Product Candidate have been and are being conducted in compliance in all material respects with applicable Laws, including the FDA’s standards for current good manufacturing practices, including applicable requirements contained in 21 C.F.R. Parts 210, 211 and 600-610 and the respective counterparts thereof promulgated by Governmental Authorities in countries outside the United States.

(h) Neither the Company nor, to the Knowledge of the Company, any manufacturing site of a contract manufacturer or laboratory, with respect to any Company Product Candidate, (i) is subject to a Drug/Device Regulatory Agency shutdown or import or export prohibition or (ii) has received any Form FDA 483, notice of violation, warning letter, untitled letter or similar correspondence or notice from the FDA or other Drug/Device Regulatory Agency alleging or asserting noncompliance with any applicable Law, in each case, that have not been complied with or closed to the satisfaction of the relevant Drug/Device Regulatory Agency, and, to the Knowledge of the Company, neither the FDA nor any other Drug/Device Regulatory Agency is considering such action.

3.15 Legal Proceedings; Orders.

(a) There is no pending Legal Proceeding and, to the Knowledge of the Company, no Person has threatened in writing to commence any Legal Proceeding: (i) that involves the Company or any of its Subsidiaries or any Company Associate (in his or her capacity as such) or any of the material assets owned or used by the Company or any of its Subsidiaries or (ii) that challenges, or that may have the effect of preventing, delaying, making illegal or otherwise interfering with, the Contemplated Transactions.

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(b) There is no Order to which the Company or any of its Subsidiaries, or any of the material assets owned or used by the Company or any of its Subsidiaries, is subject. To the Knowledge of the Company, no officer or Company Key Employee is subject to any Order that prohibits such officer or Company Key Employee from engaging in or continuing in any conduct, activity or practice relating to the Company or any of its Subsidiaries or any material assets owned or used by the Company or any of its Subsidiaries.

3.16 Tax Matters.

(a) The Company has timely filed (or caused to be timely filed) all income Tax Returns and all other material Tax Returns required to be filed by the Company under applicable Law (taking into account any applicable extensions). All such Tax Returns were true, correct and complete in all material respects. Subject to exceptions as would not be material, no claim has been made by a Governmental Authority in a jurisdiction where the Company does not file Tax Returns that the Company is subject to taxation by that jurisdiction.

(b) All material amounts of Taxes due and owing by the Company (whether or not shown on any Tax Return) have been timely paid (taking into account any applicable extensions).

(c) The Company has withheld and paid to the appropriate Governmental Authority all material Taxes required to have been withheld and paid in connection with any amounts paid or owing to any employee, independent contractor, creditor, stockholder or other third party.

(d) There are no Encumbrances for a material amount of Taxes (other Encumbrances described in clause (a) of the definition of “Permitted Encumbrances”) upon any of the assets of the Company.

(e) No deficiencies for a material amount of Taxes with respect to the Company have been claimed, proposed or assessed by any Governmental Authority in writing that have not been timely paid in full. There are no pending (or, based on written notice, threatened) material audits, assessments, examinations or other actions for or relating to any liability in respect of Taxes of the Company. The Company has not granted a waiver of any statute of limitations in respect of a material amount of Taxes or an extension of time with respect to a material Tax assessment or deficiency that, in each case, is currently in effect.

(f) The Company has not been a United States real property holding corporation within the meaning of Section 897(c)(2) of the Code in the last five (5) years.

(g) The Company is not a party to any Tax allocation, Tax sharing or similar agreement (including indemnity arrangements), other than customary commercial Contracts entered into in the Ordinary Course of Business the primary purpose of which does not relate to Tax (an “Ordinary Course Agreement”).

(h) The Company has not been a member of an affiliated group filing a consolidated U.S. federal income Tax Return (other than a group the common parent of which is the Company). The Company has no Liability for the Taxes of any Person under Treasury Regulations Section 1.1502-6 (or any similar provision of state, local, or foreign law), as a transferee or successor, or by Contract (other than an Ordinary Course Agreement).

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(i) The Company has not distributed stock of another Person, or has had its stock distributed by another Person, in a transaction that was purported or intended to be governed in whole or in part by Section 355 of the Code or Section 361 of the Code.

(j) The Company has not entered into any transaction identified as a “listed transaction” for purposes of Treasury Regulations Sections 1.6011-4(b)(2) or 301.6111-2(b)(2).

(k) The Company is not aware of any facts or circumstances and has not taken or agreed to take any action, in each case, that would reasonably be expected to prevent or impede the Intended Tax Treatment.

3.17 Employee and Labor Matters; Benefit Plans.

(a) Section 3.17(a) of the Company Disclosure Schedule sets forth (on an anonymized basis), for each Company Associate who is an employee of the Company or any of its Subsidiaries, whether full- or part-time, annual salary and wage rate, most recent annual bonus received and current annual bonus opportunity. No Company Key Employee has indicated to the Company, or any of its Subsidiaries, that he or she intends to resign or retire as a result of the transactions contemplated by this Agreement or otherwise.

(b) The employment of the Company’s and each of its Subsidiaries’ employees is terminable by the Company and/or its applicable Subsidiary at will. The Company has made available to Magenta accurate and complete copies of all employee manuals and handbooks, disclosure materials, policy statements and other materials relating to the employment of the Company Associates to the extent currently effective and material.

(c) Neither the Company nor any of its Subsidiaries is a party to, bound by the terms of, and does not have a duty to bargain under, any collective bargaining agreement or other Contract with a labor organization representing its employees, and there are no labor organizations representing or, to the Knowledge of the Company, purporting to represent or seeking to represent any employees of the Company.

(d) Section 3.17(d) of the Company Disclosure Schedule lists all Company Employee Plans (other than employment arrangements which are terminable “at will” without any contractual obligation on the part of the Company or any of its Subsidiaries to make any severance, termination, change in control or similar payment and that are substantively identical to the employment arrangements made available to Magenta).

(e) Each Company Employee Plan that is intended to be qualified under Section 401(a) of the Code has received a favorable determination or opinion letter with respect to such qualified status from the IRS. To the Knowledge of the Company, nothing has occurred that would reasonably be expected to adversely affect the qualified status of any such Company Employee Plan or the exempt status of any related trust.

(f) Each Company Employee Plan has been established, maintained and operated in compliance, in all material respects, with its terms all applicable Law, including, without limitation, the Code, ERISA and the Affordable Care Act. No Legal Proceeding (other than those relating to routine claims for benefits) is pending or, to the Knowledge of the Company, threatened with respect to

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any Company Employee Plan. All payments and/or contributions required to have been made with respect to all Company Employee Plans either have been made or have been accrued in accordance with the terms of the applicable Company Employee Plan and applicable Law.

(g) Neither the Company nor any of its ERISA Affiliates maintains, contributes to or is required to contribute to, or has, in the past six (6) years, maintained, contributed to or been required to contribute to (i) any “employee benefit plan” that is or was subject to Title IV or Section 302 of ERISA or Section 412 of the Code, (ii) a Multiemployer Plan, (iii) any funded welfare benefit plan within the meaning of Section 419 of the Code, (iv) any Multiple Employer Plan, or (v) any Multiple Employer Welfare Arrangement. Neither the Company nor any of its ERISA Affiliates has ever incurred any liability under Title IV of ERISA.

(h) No Company Employee Plan provides for medical or other welfare benefits to any service provider beyond termination of service or retirement, other than (1) pursuant to COBRA or an analogous state law requirement or (2) continuation coverage through the end of the month in which such termination or retirement occurs. The Company does not sponsor or maintain any self-funded medical or long-term disability benefit plan.

(i) No Company Employee Plan is subject to any law of a foreign jurisdiction outside of the United States.

(j) Each Company Employee Plan that constitutes in any part a “nonqualified deferred compensation plan” (as such term is defined under Section 409A(d)(1) of the Code and the guidance thereunder) (each, a “Company 409A Plan”) has been operated and maintained in all material respects in operational and documentary compliance with the requirements of Section 409A of the Code and the applicable guidance thereunder. No payment to be made under any Company 409A Plan is or, when made in accordance with the terms of the Company 409A Plan, will be subject to the penalties of Section 409A(a)(1) of the Code.

(k) The Company and each of its Subsidiaries is, and has been, in material compliance with all applicable federal, state and local laws, rules and regulations respecting employment, employment practices, terms and conditions of employment, worker classification, tax withholding, prohibited discrimination, retaliation and harassment, equal employment, fair employment practices, meal and rest periods, immigration status, employee and workplace safety and health, wages (including overtime wages), compensation, hours of work, “plant closings” and “mass layoffs” within the meaning of the Worker Adjustment and Retraining Act of 1988 or similar state or local law (the “WARN Act”), labor practices or disputes, restrictive covenants, employment agreements, workers’ compensation and long-term disability policies, leaves of absence and worker privacy (collectively, “Employment-Related Laws”), and in each case, with respect to employees of the Company and any of its Subsidiaries: (i) has withheld and reported all material amounts required by law or by agreement to be withheld and reported with respect to wages, salaries and other payments to employees, (ii) is not liable for any material amounts of arrears of wages, severance pay or any Taxes or any penalty for failure to comply with any of the foregoing and (iii) is not liable for any material payment to any trust or other fund governed by or maintained by or on behalf of any Governmental Authority, with respect to unemployment compensation benefits, social security or other benefits or obligations for employees (other than routine payments to be made in the Ordinary Course of Business). There are no material Legal Proceedings, claims, labor disputes or organizing activities, or grievances pending or, to the Knowledge of the Company, threatened or reasonably anticipated against or involving the Company or any of its Subsidiaries or any trustee of the Company or any of its Subsidiaries relating to any employee, contingent worker, director, employment agreement or Employee Plan (other than routine claims for benefits) or Employment-Related Laws. To the Knowledge of the Company, there are no material pending or threatened or reasonably anticipated claims or actions against the Company, any

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trustee or any trustee of any Subsidiary of the Company under any workers’ compensation policy or long-term disability policy. The Company is not a party to a conciliation agreement, consent decree or other agreement or Order with any federal, state or local agency or Governmental Authority with respect to employment practices.

(l) Neither the Company nor any of its Subsidiaries has any material liability with respect to any misclassification within the past four (4) years of: (i) any Person as an independent contractor rather than as an employee, (ii) any employee leased from another employer or (iii) any employee currently or formerly classified as exempt from overtime wages. Neither the Company nor any of its Subsidiaries has taken any action which would constitute a “plant closing” or “mass layoff” within the meaning of the WARN Act, issued any notification of a plant closing or mass layoff required by the WARN Act (nor has the Company or any of its Subsidiaries been under any requirement or obligation to issue any such notification), or incurred any liability or obligation under the WARN Act that remains unsatisfied.

(m) There has never been, nor has there been any threat of, any strike, slowdown, work stoppage, lockout, job action, union, organizing activity, question concerning representation or any similar activity or dispute, affecting the Company or any of its Subsidiaries. No event has occurred within the past six months, and no condition or circumstance exists, that might directly or indirectly be likely to give rise to or provide a basis for the commencement of any such strike, slowdown, work stoppage, lockout, job action, union organizing activity, question concerning representation or any similar activity or dispute.

(n) Neither the Company nor any of its Subsidiaries is, nor has the Company nor any of its Subsidiaries been, engaged in any material unfair labor practice within the meaning of the National Labor Relations Act. There is no material Legal Proceeding, claim, labor dispute or grievance pending or, to the Knowledge of the Company, threatened or reasonably anticipated relating to any employment contract, privacy right, labor dispute, wages and hours, leave of absence, plant closing notification, workers’ compensation policy, long-term disability policy, harassment, retaliation, immigration, employment statute or regulation, safety or discrimination matter involving any current or former employee of the Company or any of its Subsidiaries including charges of unfair labor practices or discrimination complaints.

(o) There is no contract, agreement, plan or arrangement to which the Company or any of its Subsidiaries is a party or by which it is bound to compensate any of its employees or other service providers for any income or excise taxes paid pursuant to the Code, including, but not limited to, Section 4999 or Section 409A of the Code.

(p) Neither the Company nor any of its Subsidiaries is a party to any Contract that as a result of the execution and delivery of this Agreement, the stockholder approval of this Agreement, nor the consummation of the transactions contemplated hereby, could (either alone or in conjunction with any other event) result in, or cause the accelerated vesting, payment, funding or delivery of, or increase the amount or value of, any payment or benefit to any employee, officer, director or other service provider of the Company or any of its Subsidiaries.

3.18 Environmental Matters. The Company has complied with all applicable Environmental Laws, which compliance includes the possession by the Company of all permits and other Governmental Authorizations required under applicable Environmental Laws and compliance with the terms and conditions thereof, except for any failure to be in compliance that, individually or in the aggregate, would not result in a Company Material Adverse Effect. The Company has not received any written notice or other communication (in writing or otherwise), whether from a Governmental Authority, citizens group, employee or otherwise, that alleges that the Company is not in compliance with any

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Environmental Law and, to the Knowledge of the Company, there are no circumstances that may prevent or interfere with the Company’s compliance with any Environmental Law in the future, except where such failure to comply would not reasonably be expected to have a Company Material Adverse Effect. To the Knowledge of the Company: (i) no current or prior owner of any property leased or controlled by the Company has received any written notice or other communication relating to property owned or leased at any time by the Company, whether from a Governmental Authority, citizens group, employee or otherwise, that alleges that such current or prior owner or the Company is not in compliance with or violated any Environmental Law relating to such property and (ii) the Company has no material liability under any Environmental Law.

3.19 Insurance. The Company has delivered to Magenta accurate and complete copies of all material insurance policies and all material self-insurance programs and arrangements relating to the business, assets, liabilities and operations of the Company. Each of such insurance policies is in full force and effect and the Company is in compliance in all material respects with the terms thereof. Other than customary end of policy notifications from insurance carriers, the Company has not received any notice or other communication regarding any actual or possible: (i) cancellation or invalidation of any insurance policy or (ii) refusal or denial of any coverage, reservation of rights or rejection of any material claim under any insurance policy. The Company has provided timely written notice to the appropriate insurance carrier(s) of each Legal Proceeding pending against the Company, and no such carrier has issued a denial of coverage or a reservation of rights with respect to any such Legal Proceeding, or informed the Company of its intent to do so.

3.20 No Financial Advisors. Except as set forth on Section 3.20 of the Company Disclosure Schedule, no broker, finder or investment banker is entitled to any brokerage fee, finder’s fee, opinion fee, success fee, transaction fee or other fee or commission in connection with the Contemplated Transactions based upon arrangements made by or on behalf of the Company.

3.21 Transactions with Affiliates. Section 3.21 of the Company Disclosure Schedule describes any material transactions or relationships between, on one hand, the Company and, on the other hand, any (a) executive officer or director of the Company or any of such executive officer’s or director’s immediate family members, (b) owner of more than 5% of the voting power of the outstanding Company Capital Stock or (c) to the Knowledge of the Company, any “related person” (within the meaning of Item 404 of Regulation S-K under the Securities Act) of any such officer, director or owner (other than the Company) in the case of each of (a), (b) or (c) that is of the type that would be required to be disclosed under Item 404 of Regulation S-K under the Securities Act.

3.22 Privacy and Data Security. The Company has complied with all applicable Privacy Laws and the applicable terms of any Company Contracts relating to privacy, security, collection or use of Personal Information of any individuals (including clinical trial participants, patients, patient family members, caregivers or advocates, physicians and other health care professionals, clinical trial investigators, researchers, pharmacists) that interact with the Company in connection with the operation of the Company’s business, except for such noncompliance as has not had, and would not reasonably be expected to have, individually or in the aggregate, a Company Material Adverse Effect. To the Knowledge of the Company, the Company has implemented and maintains reasonable written policies and procedures, satisfying the requirements of applicable Privacy Laws, concerning the privacy, security, collection and use of Personal Information (the “Privacy Policies”) and has complied with the same, except for such noncompliance as has not to the Knowledge of the Company had, and would not reasonably be expected to have, individually or in the aggregate, a Company Material Adverse Effect. To the Knowledge of the Company, as of the date hereof, no claims have been asserted or threatened against the Company by any Person alleging a violation of Privacy Laws, Privacy Policies and/or the applicable terms of any Company Contracts relating to privacy, security, collection or use of Personal Information of any individuals. To the

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Knowledge of the Company, there have been no data security incidents, personal data breaches or other adverse events or incidents related to Personal Information or Company data in the custody or control of the Company or any service provider acting on behalf of the Company, in each case where such incident, breach or event would result in a notification obligation to any Person under applicable law or pursuant to the terms of any Company Contract.

3.23 No Other Representations or Warranties. The Company hereby acknowledges and agrees that, except for the representations and warranties contained in this Agreement, neither Magenta nor any other person on behalf of Magenta makes any express or implied representation or warranty with respect to Magenta or with respect to any other information provided to the Company, any of its stockholders or any of their respective Affiliates in connection with the Contemplated Transactions, and (subject to the express representations and warranties of Magenta set forth in Section 4 (in each case as qualified and limited by the Magenta Disclosure Schedule)) none of the Company, or any of its Representatives or stockholders, has relied on any such information (including the accuracy or completeness thereof).

Section 4. Representations and Warranties of Magenta and Merger Sub.

Except (i) as set forth in the written disclosure schedule delivered by Magenta to the Company (the “Magenta Disclosure Schedule”) or (ii) as disclosed in the Magenta SEC Documents filed with the SEC prior to the date hereof and publicly available on the SEC’s Electronic Data Gathering Analysis and Retrieval system (but (A) without giving effect to any amendment thereof filed with, or furnished to the SEC on or after the date hereof and (B) excluding any disclosures contained under the heading “Risk Factors” and any disclosure of risks included in any “forward-looking statements” disclaimer or in any other section to the extent they are forward-looking statements or cautionary, predictive or forward-looking in nature), it being understood that any matter disclosed in the Magenta SEC Documents shall be deemed to be disclosed in a section of the Magenta Disclosure Schedule only to the extent that is readily apparent from a reading of such Magenta SEC Documents that is applicable to such section or subsection of the Magenta Disclosure Schedule, Magenta and Merger Sub represent and warrant to the Company as follows:

4.1 Due Organization; Subsidiaries.

(a) Each of Magenta and its Subsidiaries (including Merger Sub) is a corporation or limited liability company duly incorporated or formed, validly existing and in good standing under the Laws of the jurisdiction of its incorporation or organization and has all necessary corporate power and authority: (i) to conduct its business in the manner in which its business is currently being conducted, (ii) to own or lease and use its property and assets in the manner in which its property and assets are currently owned or leased and used and (iii) to perform its obligations under all Contracts by which it is bound. Since the date of their formation, Merger Sub have not engaged in any activities other than in connection with or as contemplated by this Agreement. All of Magenta’s Subsidiaries are wholly owned by Magenta.

(b) Each of Magenta and its Subsidiaries is licensed and qualified to do business, and is in good standing (to the extent applicable in such jurisdiction), under the Laws of all jurisdictions where the nature of its business in the manner in which its business is currently being conducted requires such licensing or qualification other than in jurisdictions where the failure to be so qualified individually or in the aggregate would not be reasonably expected to have a Magenta Material Adverse Effect.

(c) Except as set forth on Section 4.1(c). of the Magenta Disclosure Schedule, Magenta has no Subsidiaries other than Merger Sub and Magenta does not own any capital stock of, or any equity ownership or profit sharing interest of any nature in, or control directly or indirectly, any other Entity other than Merger Sub. Magenta is not and has not otherwise been, directly or indirectly, a party to, member

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of or participant in any partnership, joint venture or similar business entity. Magenta has not agreed and is not obligated to make, nor is Magenta bound by any Contract under which it may become obligated to make, any future investment in or capital contribution to any other Entity. Magenta has not, at any time, been a general partner of, and has not otherwise been liable for any of the debts or other obligations of, any general partnership, limited partnership or other Entity.

4.2 Organizational Documents. Magenta has delivered to the Company accurate and complete copies of Magenta’s Organizational Documents. Magenta is not in breach or violation of its Organizational Documents in any material respect.

4.3 Authority; Binding Nature of Agreement. Each of Magenta and Merger Sub has all necessary corporate power and authority to enter into and to perform its obligations under this Agreement and to consummate the Contemplated Transactions. The Magenta Board (at meetings duly called and held) has: (a) determined that the Contemplated Transactions are fair to, advisable and in the best interests of Magenta and its stockholders, (b) approved and declared advisable this Agreement and the Contemplated Transactions, including the issuance of shares of Magenta Common Stock to the stockholders of the Company pursuant to the terms of this Agreement and (c) determined to recommend, upon the terms and subject to the conditions set forth in this Agreement, that the stockholders of Magenta vote to approve the Contemplated Transactions, and, if deemed necessary by Magenta and the Company, the Nasdaq Reverse Split pursuant to the terms of this Agreement. The Merger Sub Board (by unanimous written consent) has: (x) determined that the Contemplated Transactions are fair to, advisable and in the best interests of Merger Sub and its sole stockholder, (y) deemed advisable and approved this Agreement and the Contemplated Transactions and (z) determined to recommend, upon the terms and subject to the conditions set forth in this Agreement, that the stockholder of Merger Sub vote to adopt this Agreement and thereby approve the Contemplated Transactions. This Agreement has been duly executed and delivered by Magenta and Merger Sub and, assuming the due authorization, execution and delivery by the Company, constitutes the legal, valid and binding obligation of Magenta and Merger Sub, enforceable against each of Magenta and Merger Sub in accordance with its terms, subject to the Enforceability Exceptions.

4.4 Vote Required. The affirmative vote of a majority of (a) the shares of Magenta Common Stock properly cast is the only vote of the holders of any class or series of Magenta’s capital stock necessary to approve this Agreement and thereby approve the Contemplated Transactions, including the issuance of shares of Magenta Common Stock to the stockholders of the Company pursuant to the terms of this Agreement and (b) if deemed necessary by Magenta and the Company, the shares of Magenta Common Stock entitled to vote thereon is the only vote of the holders of any class or series of Magenta’s capital stock necessary to approve an amendment to Magenta’s certificate of incorporation to effect the Nasdaq Reverse Split (collectively, the “Required Magenta Stockholder Vote”).

4.5 Non-Contravention; Consents.

(a) Subject to obtaining the Required Magenta Stockholder Vote and the filing of the Certificate of Merger required by the DGCL, neither (x) the execution, delivery or performance of this Agreement by Magenta or Merger Sub, nor (y) the consummation of the Contemplated Transactions, will directly or indirectly (with or without notice or lapse of time):

(i) contravene, conflict with or result in a violation of any of the provisions of the Organizational Documents of Magenta or its Subsidiaries;

(ii) contravene, conflict with or result in a material violation of, or give any Governmental Authority or other Person the right to challenge the Contemplated Transactions or to exercise any remedy or obtain any relief under, any Law or any Order to which Magenta or its Subsidiaries or any of the assets owned or used by Magenta or its Subsidiaries, is subject;

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(iii) contravene, conflict with or result in a material violation of any of the terms or requirements of, or give any Governmental Authority the right to revoke, withdraw, suspend, cancel, terminate or modify, any Governmental Authorization that is held by Magenta or its Subsidiaries or that otherwise relates to the business of Magenta, or any of the assets owned, leased or used by Magenta;

(iv) contravene, conflict with or result in a violation or breach of, or result in a default under, any provision of any Magenta Material Contract, or give any Person the right to: (A) declare a default or exercise any remedy under any Magenta Material Contract, (B) any material payment, rebate, chargeback, penalty or change in delivery schedule under any such Magenta Material Contract, (C) accelerate the maturity or performance of any Magenta Material Contract or (D) cancel, terminate or modify any term of any Magenta Material Contract, except in the case of any nonmaterial breach, default, penalty or modification; or

(v) result in the imposition or creation of any Encumbrance upon or with respect to any asset owned or used by Magenta or its Subsidiaries (except for Permitted Encumbrances).

(b) Except for (i) any Consent set forth on Section 4.5 of the Magenta Disclosure Schedule under any Magenta Contract, (ii) the Required Magenta Stockholder Vote, (iii) the filing of the Certificate of Merger with the Secretary of State of the State of Delaware pursuant to the DGCL, and (iv) such consents, waivers, approvals, orders, authorizations, registrations, declarations and filings as may be required under applicable federal and state securities laws, neither Magenta nor any of its Subsidiaries was, is or will be required to make any filing with or give any notice to, or to obtain any Consent from, any Person in connection with (x) the execution, delivery or performance of this Agreement or (y) the consummation of the Contemplated Transactions.

(c) The Magenta Board and the Merger Sub Board have taken and will take all actions necessary to ensure that the restrictions applicable to business combinations contained in Section 203 of the DGCL are, and will be, inapplicable to the execution, delivery and performance of this Agreement and to the consummation of the Contemplated Transactions. No other state takeover statute or similar Law applies or purports to apply to the Merger, this Agreement or any of the other Contemplated Transactions.

4.6 Capitalization.

(a) The authorized capital stock of Magenta consists of (i) 150,000,000 shares of Magenta Common Stock of which 60,648,821 shares have been issued and are outstanding as of March 31, 2023 (the “Capitalization Date”) and (ii) 10,000,000 shares of Magenta Preferred Stock, par value $0.001 per share, of which no shares have been issued and are outstanding as of the Capitalization Date. Magenta does not hold any shares of its capital stock in its treasury.

(b) All of the outstanding shares of Magenta Common Stock have been duly authorized and validly issued, and are fully paid and nonassessable and are free of any Encumbrances. None of the outstanding shares of Magenta Common Stock is entitled or subject to any preemptive right, right of participation, right of maintenance or any similar right. None of the outstanding shares of Magenta Common Stock is subject to any right of first refusal in favor of Magenta. Except as contemplated herein, there is no Magenta Contract relating to the voting or registration of, or restricting any Person from

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purchasing, selling, pledging or otherwise disposing of (or granting any option or similar right with respect to), any shares of Magenta Common Stock. Magenta is not under any obligation, nor is Magenta bound by any Contract pursuant to which it may become obligated, to repurchase, redeem or otherwise acquire any outstanding shares of Magenta Common Stock or other securities. Section 4.6(b) of the Magenta Disclosure Schedule accurately and completely describes all repurchase rights held by Magenta with respect to shares of Magenta Common Stock (including shares issued pursuant to the exercise of stock options) and specifies which of those repurchase rights are currently exercisable.

(c) Except for the Magenta 2016 Stock Option and Grant Plan, as amended (the “Magenta 2016 Plan”) and the Magenta 2018 Stock Option and Grant Plan (the “Magenta 2018 Plan” and, together with the Magenta 2016 Plan, the “Magenta Stock Plans”) and the Magenta 2019 Employee Stock Purchase Plan (the “Magenta ESPP”), and except as set forth on Section 4.6(c) of the Magenta Disclosure Schedule, Magenta does not have any stock option plan or any other plan, program, agreement or arrangement providing for any equity-based compensation for any Person. As of the Capitalization Date, Magenta has reserved 17,287,588 shares of Magenta Common Stock for issuance under the Magenta Stock Plans, of which 2,865,613 shares have been issued and are currently outstanding, 7,190,312 shares have been reserved for issuance upon exercise or settlement of Magenta Options and Magenta Restricted Stock Units, as applicable, granted under the Magenta Stock Plans, and 7,231,663 shares remain available for future issuance pursuant to the Magenta Stock Plans. As of the Capitalization Date, Magenta has reserved 754,516 shares of Magenta Common Stock for future issuance pursuant to the Magenta ESPP (of which 161,277 shares have been issued and are currently outstanding). Section 4.6(c) of the Magenta Disclosure Schedule sets forth the following information with respect to each Magenta Option and Magenta Restricted Stock Unit outstanding as of the Capitalization Date, as applicable: (i) the name of the holder, (ii) the number of shares of Magenta Common Stock subject to such Magenta Option and Magenta Restricted Stock Units at the time of grant, (iii) the number of shares of Magenta Common Stock subject to such Magenta Option and Magenta Restricted Stock Units as of the Capitalization Date, (iv) the exercise price of such Magenta Option, (v) the date on which such Magenta Option and Magenta Restricted Stock Units was granted, (vi) the applicable vesting schedule, including any acceleration provisions and the number of vested and unvested shares as of the Capitalization Date, (vii) the date on which such Magenta Option expires, (viii) whether such Magenta Option is intended to be an “incentive stock option” (as defined in the Code) or a nonqualified stock option and (ix) in the case of a Magenta Option, the plan pursuant to which such Magenta Option was granted. Magenta has made available to the Company accurate and complete copies of equity incentive plans pursuant to which Magenta has equity-based awards, the forms of all award agreements evidencing such equity-based awards and evidence of board and stockholder approval of the Magenta Stock Plans and any amendments thereto.

(d) Except for the outstanding Magenta Options and Magenta Restricted Stock Units or as set forth on Section 4.6(d) of the Magenta Disclosure Schedule, there is no: (i) outstanding subscription, option, call, warrant or right (whether or not currently exercisable) to acquire any shares of the capital stock or other securities of Magenta, (ii) outstanding security, instrument or obligation that is or may become convertible into or exchangeable for any shares of the capital stock or other securities of Magenta, (iii) stockholder rights plan (or similar plan commonly referred to as a “poison pill”) or Contract under which Magenta is or may become obligated to sell or otherwise issue any shares of its capital stock or any other securities or (iv) condition or circumstance that may give rise to or provide a basis for the assertion of a claim by any Person to the effect that such Person is entitled to acquire or receive any shares of capital stock or other securities of Magenta. There are no outstanding or authorized stock appreciation, phantom stock, profit participation or other similar rights with respect to Magenta. Magenta and the Magenta Board have taken all action required to (a) render the Magenta Rights inapplicable to this Agreement, the Merger and the other transactions contemplated hereby, (b) ensure that the Company is not an Acquiring Person (as defined in the Rights Agreement) and (c) cause the Magenta Rights to expire immediately prior to the Effective Time without any payment being made in respect thereof.

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(e) All outstanding shares of Magenta Common Stock, Magenta Options, Magenta Restricted Stock Units and other securities of Magenta have been issued and granted in compliance with (i) all applicable securities laws and other applicable Law and (ii) all requirements set forth in applicable Contracts.

(f) With respect to Magenta Options and Magenta Restricted Stock Units granted pursuant to the Magenta Stock Plans, (i) each grant of a Magenta Option or Magenta Restricted Stock Unit was duly authorized no later than the date on which the grant of such Magenta Option and Magenta Restricted Stock Unit was by its terms to be effective (the “Magenta Grant Date”) by all necessary corporate action, including, as applicable, approval by the Magenta Board (or a duly constituted and authorized committee thereof) or duly authorized officer and any required stockholder approval by the necessary number of votes or written consents, (ii) each Magenta Option and Magenta Restricted Stock Unit grant was made in accordance with the terms of the Magenta Stock Plan pursuant to which it was granted and all other applicable Law and regulatory rules or requirements, and (iii) the per share exercise price of each Magenta Option was not less than the fair market value of a share of Magenta Common Stock on the applicable Magenta Grant Date.

4.7 SEC Filings; Financial Statements.

(a) Magenta has filed or furnished, as applicable, on a timely basis all forms, statements, certifications, reports and documents required to be filed or furnished by it with the SEC under the Exchange Act or the Securities Act (the “Magenta SEC Documents”). As of the time it was filed with the SEC (or, if amended or superseded by a filing prior to the date of this Agreement, then on the date of such filing), each of the Magenta SEC Documents complied in all material respects with the applicable requirements of the Securities Act or the Exchange Act (as the case may be) and as of the time they were filed, none of the Magenta SEC Documents contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. The certifications and statements required by (i) Rule 13a-14 under the Exchange Act and (ii) 18 U.S.C. §1350 (Section 906 of the Sarbanes-Oxley Act) relating to the Magenta SEC Documents (collectively, the “Certifications”) are accurate and complete and comply as to form and content with all applicable Laws. As used in this Section 4.7, the term “file” and variations thereof shall be broadly construed to include any manner in which a document or information is furnished, supplied or otherwise made available to the SEC.

(b) The financial statements (including any related notes) contained or incorporated by reference in the Magenta SEC Documents: (i) complied as to form in all material respects with the Securities Act and the Exchange Act, as applicable, and the published rules and regulations of the SEC applicable thereto, (ii) were prepared in accordance with GAAP (except as may be indicated in the notes to such financial statements or, in the case of unaudited financial statements, as permitted by Form 10-Q of the SEC, and except that the unaudited financial statements may not contain footnotes and are subject to normal and recurring year-end adjustments that are not reasonably expected to be material in amount) applied on a consistent basis unless otherwise noted therein throughout the periods indicated and (iii) fairly present, in all material respects, the financial position of Magenta as of the respective dates thereof and the results of operations and cash flows of Magenta for the periods covered thereby. Other than as expressly disclosed in the Magenta SEC Documents filed prior to the date hereof, there has been no material change in Magenta’s accounting methods or principles that would be required to be disclosed in Magenta’s financial statements in accordance with GAAP. The books of account and other financial records of Magenta and each of its Subsidiaries are true and complete in all material respects.

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(c) Magenta’s auditor has at all times since the date of enactment of the Sarbanes-Oxley Act been: (i) a registered public accounting firm (as defined in Section 2(a)(12) of the Sarbanes-Oxley Act), (ii) to the Knowledge of Magenta, “independent” with respect to Magenta within the meaning of Regulation S-X under the Exchange Act and (iii) to the Knowledge of Magenta, in compliance with subsections (g) through (l) of Section 10A of the Exchange Act and the rules and regulations promulgated by the SEC and the Public Company Accounting Oversight Board thereunder.

(d) Except as set forth on Section 4.6(d) of the Magenta Disclosure Schedule, Magenta has not received any comment letter from the SEC or the staff thereof or any correspondence from Nasdaq or the staff thereof relating to the delisting or maintenance of listing of the Magenta Common Stock on Nasdaq. Magenta has not disclosed any unresolved comments in the Magenta SEC Documents.

(e) There have been no formal internal investigations regarding financial reporting or accounting policies and practices discussed with, reviewed by or initiated at the direction of the chief executive officer, chief financial officer or general counsel of Magenta, the Magenta Board or any committee thereof, other than ordinary course audits or reviews of accounting policies and practices or internal controls required by the Sarbanes-Oxley Act.

(f) Except as set forth on Section 4.7(f) of the Magenta Disclosure Schedule, Magenta is in compliance in all material respects with the applicable provisions of the Sarbanes-Oxley Act, the Exchange Act and the applicable listing and governance rules and regulations of Nasdaq.

(g) Magenta maintains a system of internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) of the Exchange Act) that is sufficient to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with GAAP, including policies and procedures sufficient to provide reasonable assurance (i) that Magenta maintains records that in reasonable detail accurately and fairly reflect Magenta’s transactions and dispositions of assets, (ii) that transactions are recorded as necessary to permit preparation of financial statements in accordance with GAAP, (iii) that receipts and expenditures are made only in accordance with the authorization policy and (iv) regarding prevention or timely detection of the unauthorized acquisition, use or disposition of Magenta’s assets that could have a material effect on Magenta’s financial statements. Magenta has evaluated the effectiveness of Magenta’s internal control over financial reporting and, to the extent required by applicable Law, presented in any applicable Magenta SEC Document that is a report on Form 10-K or Form 10-Q (or any amendment thereto) its conclusions about the effectiveness of the internal control over financial reporting as of the end of the period covered by such report or amendment based on such evaluation. Magenta has disclosed to Magenta’s auditors and the Audit Committee of the Magenta Board (and made available to the Company a summary of the significant aspects of such disclosure) (A) all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting that are reasonably likely to adversely affect Magenta’s ability to record, process, summarize and report financial information and (B) any fraud, whether or not material, that involves management or other employees who have a significant role in Magenta’s or its Subsidiaries’ internal control over financial reporting. Except as disclosed in the Magenta SEC Documents filed prior to the date hereof, Magenta’s internal control over financial reporting is effective at the reasonable assurance level and Magenta has not identified any material weaknesses in the design or operation of Magenta’s internal control over financial reporting.

(h) Magenta’s “disclosure controls and procedures” (as defined in Rules 13a-15(e) and 15d-15(e) of the Exchange Act) are designed to ensure that all information (both financial and nonfinancial) required to be disclosed by Magenta in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the rules and forms of the SEC, and that all such information is accumulated and communicated to Magenta’s principal executive officer and principal financial officer as appropriate to allow timely decisions regarding required disclosure and to make the Certifications and such disclosure controls and procedures are effective. Magenta has carried out evaluation of the effectiveness of its disclosure controls and procedures as required by Rule 13a-15 of the Exchange Act.

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(i) Magenta has not been and is not currently determined to be a “shell company” as defined under Section 12b-2 of the Exchange Act.

4.8 Absence of Changes. Except as set forth on Section 4.8 of the Magenta Disclosure Schedule, between December 31, 2022 and the date of this Agreement, Magenta has conducted its business only in the Ordinary Course of Business (except for the execution and performance of this Agreement and the discussions, negotiations and transactions related thereto) and there has not been any (a) Magenta Material Adverse Effect or (b) action, event or occurrence that would have required consent of Magenta pursuant to Section (a)5.1(b) of this Agreement had such action, event or occurrence taken place after the execution and delivery of this Agreement.

4.9 Absence of Undisclosed Liabilities. Since December 31, 2022, neither Magenta nor any of its Subsidiaries has any Liability of a type required to be reflected or reserved for on a balance sheet prepared in accordance with GAAP, except for: (a) Liabilities disclosed, reflected or reserved against in the Magenta Balance Sheet, (b) normal and recurring current Liabilities that have been incurred by Magenta or its Subsidiaries since the date of the Magenta Balance Sheet in the Ordinary Course of Business (none of which relates to any breach of contract, breach of warranty, tort, infringement or violation of Law), (c) Liabilities for performance of obligations of Magenta or any of its Subsidiaries under Magenta Contracts, (d) Liabilities incurred in connection with the Magenta Legacy Business or the Contemplated Transactions and (e) Liabilities described in Section 4.9 of the Magenta Disclosure Schedule.

4.10 Title to Assets. Each of Magenta and its Subsidiaries owns, and has good and valid title to, or, in the case of leased properties and assets, valid leasehold interests in, all tangible properties or tangible assets and equipment used or held for use in its business or operations or purported to be owned by it, including: (a) all tangible assets reflected on the Magenta Balance Sheet and (b) all other tangible assets reflected in the books and records of Magenta as being owned by Magenta. All of such assets are owned or, in the case of leased assets, leased by Magenta or any of its Subsidiaries free and clear of any Encumbrances, other than Permitted Encumbrances.

4.11 Real Property; Leasehold. Neither Magenta nor any of its Subsidiaries owns or has ever owned any real property. Magenta has made available to the Company (a) an accurate and complete list of all real properties with respect to which Magenta directly or indirectly holds a valid leasehold interest as well as any other real estate that is in the possession of or leased by Magenta or any of its Subsidiaries and (b) copies of all leases under which any such real property is possessed (the “Magenta Real Estate Leases”), each of which is in full force and effect, with no existing material default thereunder.

4.12 Intellectual Property.

(a) Section 4.12(a) of the Magenta Disclosure Schedule is an accurate, true and complete listing of all Magenta Registered IP.

(b) Section 4.12(b) of the Magenta Disclosure Schedule accurately identifies (i) all Magenta Contracts pursuant to which any Magenta IP Rights are licensed to Magenta (other than (A) any non-customized software that (1) is so licensed solely in executable or object code form pursuant to a nonexclusive, internal use software license and other Intellectual Property associated with such software and (2) is not incorporated into, or material to the development, manufacturing, or distribution of, any of Magenta products or services, (B) any Intellectual Property licensed on a nonexclusive basis ancillary to the purchase or use of equipment, reagents or other materials, (C) any confidential information provided under confidentiality agreements and (D) agreements between Magenta and its employees in Magenta’s standard form thereof) and (ii) whether the license or licenses granted to Magenta are exclusive or nonexclusive.

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(c) Section 4.12(c) of the Magenta Disclosure Schedule accurately identifies each Magenta Contract pursuant to which any Person has been granted any license under, or otherwise has received or acquired any right (whether or not currently exercisable) or interest in, any Magenta IP Rights (other than (i) any confidential information provided under confidentiality agreements and (ii) any Magenta IP Rights nonexclusively licensed to academic collaborators, suppliers or service providers for the sole purpose of enabling such academic collaborator, supplier or service providers to provide services for Magenta’s benefit).

(d) Neither Magenta not any of its Subsidiaries is bound by, and no Magenta IP Rights are subject to, any Contract containing any covenant or other provision that in any way limits or restricts the ability of Magenta or any of its Subsidiaries to use, exploit, assert, or enforce any Magenta IP Rights anywhere in the world.

(e) Magenta or one of its Subsidiaries exclusively owns all right, title, and interest to and in the Magenta IP Rights (other than (i) Magenta IP Rights licensed to Magenta, or co-owned rights each as identified in Section 4.12(c) of the Magenta Disclosure Schedule, (ii) any non-customized software that (A) is licensed to Magenta solely in executable or object code form pursuant to a nonexclusive, internal use software license and other Intellectual Property associated with such software and (B) is not incorporated into, or material to the development, manufacturing or distribution of, any of Magenta or its Subsidiaries’ products or services and (iii) any Intellectual Property licensed on a nonexclusive basis ancillary to the purchase or use of equipment, reagents or other materials), in each case, free and clear of any Encumbrances (other than Permitted Encumbrances). Without limiting the generality of the foregoing:

(i) All documents and instruments necessary to register or apply for or renew registration of Magenta Registered IP have been validly executed, delivered, and filed in a timely manner with the appropriate Governmental Authority.

(ii) Each Person who is or was an employee or contractor of Magenta or any of its Subsidiaries and who is or was involved in the creation or development of any Intellectual Property for Magenta or any of its Subsidiaries has signed a valid, enforceable agreement containing a present assignment of such Intellectual Property to Magenta or such Subsidiary and confidentiality provisions protecting trade secrets and confidential information of Magenta and its Subsidiaries.

(iii) To the Knowledge of Magenta, no current or former stockholder, officer, director or employee of Magenta or any of its Subsidiaries has any claim, right (whether or not currently exercisable), or interest to or in any Magenta IP Rights purported to be owned by Magenta. To the Knowledge of Magenta, no employee of Magenta or any of its Subsidiaries is (a) bound by or otherwise subject to any Contract restricting him or her from performing his or her duties for Magenta or such Subsidiary or (b) in breach of any Contract with any former employer or other Person concerning Magenta IP Rights purported to be owned by Magenta or such Subsidiary or confidentiality provisions protecting trade secrets and confidential information comprising Magenta IP Rights purported to be owned by Magenta or such Subsidiary.

(iv) No funding, facilities or personnel of any Governmental Authority were used, directly or indirectly, to develop or create, in whole or in part, any Magenta IP Rights in which Magenta or any of its Subsidiaries has an ownership interest.

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(v) Magenta and each of its Subsidiaries has taken reasonable steps to maintain the confidentiality of and otherwise protect and enforce its rights in all proprietary information that Magenta or such Subsidiary holds, or purports to hold, as confidential or a trade secret.

(vi) Magenta or any of its Subsidiaries has not assigned or otherwise transferred ownership of, or agreed to assign or otherwise transfer ownership of, any Magenta IP Rights to any other Person.

(f) Magenta has delivered, or made available to the Company, a complete and accurate copy of all material Magenta IP Rights Agreements.

(g) The manufacture, marketing, offering for sale, sale, importation, use or intended use or other disposal of any product as currently sold or under development by Magenta does not violate any license or agreement between Magenta or its Subsidiaries and any third party in any material respect, and, to the Knowledge of Magenta, does not infringe or misappropriate any valid and issued Patent right or other Intellectual Property of any other Person, which infringement or misappropriation would reasonably be expected to have a Magenta Material Adverse Effect. To the Knowledge of Magenta, no third party is infringing upon any Patents owned by Magenta within the Magenta IP Rights, or violating any Magenta IP Rights Agreement.

(h) As of the date of this Agreement, Magenta is not a party to any Legal Proceeding (including, but not limited to, opposition, interference or other proceeding in any patent or other government office) contesting the validity, ownership or right to use, sell, offer for sale, license or dispose of any Magenta IP Rights. Magenta has not received any written notice asserting that any Magenta Registered IP or the proposed use, sale, offer for sale, license or disposition of any products, methods or processes claimed or covered thereunder infringes or misappropriates or violates the rights of any other Person or that Magenta or any of its Subsidiaries have otherwise infringed, misappropriated or otherwise violated any Intellectual Property of any Person.

(i) To the Knowledge of Magenta, no trademark (whether registered or unregistered) or trade name owned, used or applied for by Magenta conflicts or interferes with any trademark (whether registered or unregistered) or trade name owned, used or applied for by any other Person except as would not have a Magenta Material Adverse Effect. None of the goodwill associated with or inherent in any trademark (whether registered or unregistered) in which Magenta has or purports to have an ownership interest has been impaired as determined by Magenta in accordance with GAAP.

(j) Except as may be set forth in the Contracts listed on Section 4.12(b) or 4.12(c) of the Magenta Disclosure Schedule or as contained in license, distribution or service agreements entered into in the Ordinary Course of Business by Magenta (i) Magenta is not bound by any Contract to indemnify, defend, hold harmless or reimburse any other Person with respect to any Intellectual Property infringement, misappropriation or similar claim which is material to Magenta taken as a whole and (ii) Magenta has never assumed, or agreed to discharge or otherwise take responsibility for, any existing or potential liability of another Person for infringement, misappropriation or violation of any Intellectual Property right, which assumption, agreement or responsibility remains in force as of the date of this Agreement.

(k) Neither Magenta nor any of its Subsidiaries is party to any Contract that, as a result of such execution, delivery and performance of this Agreement, will cause the grant of any license or other right to any Magenta IP Rights, result in breach of, default under or termination of such Contract with respect to any Magenta IP Rights, or impair the right of Magenta or the Surviving Corporation

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and its Subsidiaries to use, sell or license or enforce any Magenta IP Rights or portion thereof, except for the occurrence of any such grant or impairment that would not individually or in the aggregate, reasonably be expected to result in a Magenta Material Adverse Effect.

4.13 Agreements, Contracts and Commitments.

(a) Section 4.13 of the Magenta Disclosure Schedule identifies each Magenta Contract that is in effect as of the date of this Agreement (each, an “Magenta Material Contract” and collectively, the “Magenta Material Contracts”):

(i) each Magenta Contract relating to any material bonus, deferred compensation, severance, incentive compensation, pension, profit-sharing or retirement plans, or any other employee benefit plans or arrangements;

(ii) each Magenta Contract requiring payments by Magenta after the date of this Agreement in excess of $100,000 pursuant to its express terms relating to the employment of, or the performance of employment-related services by, any Person, including any employee, consultant or independent contractor, or Entity providing employment related, consulting or independent contractor services, not terminable by Magenta on thirty (30) calendar days’ or less notice without liability, except to the extent general principles of wrongful termination Law may limit Magenta’s, or such successor’s ability to terminate employees at will;

(iii) each Magenta Contract relating to any agreement or plan, including any option plan, stock appreciation right plan or stock purchase plan, any of the benefits of which will be increased or the vesting of benefits of which will be accelerated, by the occurrence of any of the Contemplated Transactions (either alone or in conjunction with any other event, such as termination of employment), or the value of any of the benefits of which will be calculated on the basis of any of the Contemplated Transactions;

(iv) each Magenta Contract relating to any agreement of indemnification or guaranty not entered into in the Ordinary Course of Business;

(v) each Magenta Contract containing (A) any covenant limiting the freedom of Magenta or any of its Subsidiaries to engage in any line of business or compete with any Person, or limiting the development, manufacture or distribution of the Magenta’s products or services (B) any most-favored pricing arrangement, (C) any exclusivity provision or (D) any non-solicitation provision;

(vi) each Magenta Contract (A) pursuant to which any Person granted Magenta an exclusive license under any Intellectual Property, or (B) pursuant to which Magenta granted any Person an exclusive license under any Magenta IP Rights;

(vii) each Magenta Contract relating to capital expenditures and requiring payments after the date of this Agreement in excess of $100,000 pursuant to its express terms and not cancelable without penalty;

(viii) each Magenta Contract relating to the disposition or acquisition of material assets or any ownership interest in any Entity, in each case, involving payments in excess of $100,000 after the date of this Agreement;

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(ix) each Magenta Contract relating to any mortgages, indentures, loans, notes or credit agreements, security agreements or other agreements or instruments relating to the borrowing of money or extension of credit in excess of $100,000 or creating any material Encumbrances with respect to any assets of Magenta or any loans or debt obligations with officers or directors of Magenta;

(x) each Magenta Contract requiring payment by or to Magenta after the date of this Agreement in excess of $100,000 pursuant to its express terms relating to: (A) any distribution agreement (identifying any that contain exclusivity provisions), (B) any agreement involving provision of services or products with respect to any pre-clinical or clinical development activities of Magenta, (C) any dealer, distributor, joint marketing, alliance, joint venture, cooperation, development or other agreement currently in force under which Magenta or any of its Subsidiaries has continuing obligations to develop or market any product, technology or service, or any agreement pursuant to which Magenta or any of its Subsidiaries has continuing obligations to develop any Intellectual Property that will not be owned, in whole or in part, by Magenta or such Subsidiary or (D) any Contract to license any patent, trademark registration, service mark registration, trade name or copyright registration to or from any third party to manufacture or produce any product, service or technology of Magenta or any of its Subsidiaries or any Contract to sell, distribute or commercialize any products or service of Magenta or any of its Subsidiaries, in each case, except for Magenta Contracts entered into in the Ordinary Course of Business;

(xi) each Magenta Contract with any Person, including any financial advisor, broker, finder, investment banker or other Person, providing advisory services to Magenta in connection with the Contemplated Transactions and requiring payments by Magenta after the date in this Agreement in excess of $100,000 pursuant to its express terms;

(xii) each Magenta Contract to which Magenta or any of its Subsidiaries is a party or by which any of their assets and properties is currently bound, which involves annual obligations of payment by, or annual payments to, Magenta or such Subsidiary in excess of $100,000;

(xiii) any Magenta Real Estate Lease;

(xiv) a Contract disclosed in or required to be disclosed in Section 4.12(b) or Section 4.12(c) of the Magenta Disclosure Schedule; or

(xv) any other Magenta Contract that is not terminable at will (with no penalty or payment) by Magenta or any of its Subsidiaries, and (A) which involves payment or receipt by Magenta or such Subsidiary after the date of this Agreement under any such agreement, contract or commitment of more than $100,000 in the aggregate, or obligations after the date of this Agreement in excess of $100,000 in the aggregate or (B) that is material to the business or operations of Magenta and its Subsidiaries taken as a whole.

(b) Magenta has delivered or made available to the Company accurate and complete copies of all Magenta Material Contracts, including all amendments thereto. There are no Magenta Material Contracts that are not in written form. Magenta has not nor, to Magenta’s Knowledge as of the date of this Agreement, has any other party to a Magenta Material Contract, breached, violated or defaulted under, or received notice that it breached, violated or defaulted under, any of the terms or conditions of any Magenta Material Contract in such manner as would permit any other party to cancel or terminate any such Magenta Material Contract, or would permit any other party to seek damages which would reasonably be expected to have a Magenta Material Adverse Effect. As to Magenta and its

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Subsidiaries, as of the date of this Agreement, each Magenta Material Contract is valid, binding, enforceable and in full force and effect, subject to the Enforceability Exceptions. No Person is renegotiating, or has a right pursuant to the terms of any Magenta Material Contract to change, any material amount paid or payable to Magenta under any Magenta Material Contract or any other material term or provision of any Magenta Material Contract.

4.14 Compliance; Permits; Restrictions.

(a) Magenta and each of its Subsidiaries is, and since January 1, 2022, has been in material compliance with all applicable Laws. No investigation, claim, suit, proceeding, audit, Order or other action by any Governmental Authority is pending or, to the Knowledge of Magenta, threatened against Magenta or any of its Subsidiaries. There is no agreement or Order binding upon Magenta or any of its Subsidiaries which (i) has or could reasonably be expected to have the effect of prohibiting or materially impairing any business practice of Magenta or any of its Subsidiaries, any acquisition of material property by Magenta or any of its Subsidiaries or the conduct of business by Magenta or any of its Subsidiaries as currently conducted, (ii) is reasonably likely to have an adverse effect on Magenta’s ability to comply with or perform any covenant or obligation under this Agreement or (iii) is reasonably likely to have the effect of preventing, delaying, making illegal or otherwise interfering with the Contemplated Transactions.

(b) Except for matters regarding the FDA or other Drug/Device Regulatory Agency, each of Magenta and its Subsidiaries holds all required Governmental Authorizations that are material to the operation of the business of Magenta and Merger Sub as currently conducted (collectively, the “Magenta Permits”). Section 4.14(b) of the Magenta Disclosure Schedule identifies each Magenta Permit. Each of Magenta and its Subsidiaries is in material compliance with the terms of the Magenta Permits. No Legal Proceeding is pending or, to the Knowledge of Magenta, threatened, which seeks to revoke, substantially limit, suspend or materially modify any Magenta Permit. The rights and benefits of each Magenta Permit, if any, will be available to Magenta and Surviving Corporation immediately after the Effective Time on terms substantially identical to those enjoyed by Magenta and its Subsidiaries as of the date of this Agreement and immediately prior to the Effective Time.

(c) There are no Legal Proceedings pending or, to the Knowledge of Magenta, threatened with respect to an alleged violation by Magenta or any of its Subsidiaries of the FDCA, PHSA, FDA regulations adopted thereunder, the Controlled Substances Act or any other similar Law promulgated by a Drug/Device Regulatory Agency.

(d) Each of Magenta and its Subsidiaries holds all required Governmental Authorizations issuable by any Drug/Device Regulatory Agency necessary for the conduct of the business of Magenta and Merger Sub as currently conducted, and, as applicable, the development, testing, manufacturing, processing, storage, labeling, sale, marketing, advertising, distribution and importation or exportation, as currently conducted, of any of its product candidates (the “Magenta Product Candidates”) (the “Magenta Regulatory Permits”) and no such Magenta Regulatory Permit has been (i) revoked, withdrawn, suspended, cancelled or terminated or (ii) modified in any adverse manner other than immaterial adverse modifications. Section 4.14(d) of the Magenta Disclosure Schedule identifies each Magenta Regulatory Permit. Magenta has timely maintained and is in compliance in all material respects with the Magenta Regulatory Permits and neither Magenta nor or any of its Subsidiaries has, since January 1, 2022, received any written notice or correspondence or, to the Knowledge of Magenta, other communication from any Drug/Device Regulatory Agency regarding (A) any material violation of or failure to comply materially with any term or requirement of any Magenta Regulatory Permit or (B) any revocation, withdrawal, suspension, cancellation, termination or material modification of any Magenta Regulatory Permit. Magenta has made available to the Company all information requested by the Company in Magenta’s or its

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Subsidiaries’ possession or control relating to material Magenta Product Candidates and the development, testing, manufacturing, processing, storage, labeling, sale, marketing, advertising, distribution and importation or exportation of the Magenta Product Candidates, including, but not limited to, complete copies of the following (to the extent there are any): (x) adverse event reports; pre-clinical, clinical and other study reports and material study data; inspection reports, notices of adverse findings, untitled letters, warning letters, filings and letters and other written correspondence to and from any Drug/Device Regulatory Agency; and meeting minutes with any Drug/Device Regulatory Agency and (y) similar reports, material study data, notices, letters, filings, correspondence and meeting minutes with any other Governmental Authority. All such information are accurate and complete in all material respects.

(e) All clinical, pre-clinical and other studies and tests conducted by or on behalf of, or sponsored by, Magenta or its Subsidiaries, in which Magenta or its Subsidiaries or their respective product candidates, including the Magenta Product Candidates, have participated were, since January 1, 2022, and, if still pending, are being conducted in accordance in all material respects with standard medical and scientific research procedures, and in compliance in all material respects with the applicable regulations of the Drug/Device Regulatory Agencies and other applicable Law, including, without limitation, 21 C.F.R. Parts 11, 50, 54, 56, 58, 312 and 812. Other than as set forth on Section 4.14(e) of the Magenta Disclosure Schedule, since January 1, 2022, neither Magenta nor any of its Subsidiaries has received any written notices, correspondence, or other communications from any Drug/Device Regulatory Agency requiring or, to the Knowledge of Magenta, any action to place a clinical hold order on, or otherwise terminate, delay or suspend any clinical studies conducted by or on behalf of, or sponsored by, Magenta or any of its Subsidiaries or in which Magenta or any of its Subsidiaries or its current product candidates, including the Magenta Product Candidates, have participated. Further, no clinical investigator, researcher or clinical staff participating in any clinical study conducted by or, to the Knowledge of Magenta, on behalf of Magenta or any of its Subsidiaries has been disqualified from participating in studies involving the Magenta Product Candidates, and to the Knowledge of Magenta, no such administrative action to disqualify such clinical investigators, researchers or clinical staff has been threatened or is pending.

(f) Neither Magenta nor any of its Subsidiaries and, to the Knowledge of Magenta, any contract manufacturer with respect to any Magenta Product Candidate is the subject of any pending or, to the Knowledge of Magenta, threatened investigation in respect of its business or products by the FDA pursuant to its “Fraud, Untrue Statements of Material Facts, Bribery, and Illegal Gratuities” Final Policy set forth in 56 Fed. Reg. 46191 (September 10, 1991) and any amendments thereto or by any other Drug/Device Regulatory Agency under a comparable policy. Neither Magenta nor any of its Subsidiaries and, to the Knowledge of Magenta, any contract manufacturer, nor their respective officers, employees or agents, with respect to any Magenta Product Candidate has committed any acts, made any statement or failed to make any statement, in each case in respect of its business or products that would violate FDA’s “Fraud, Untrue Statements of Material Facts, Bribery, and Illegal Gratuities” Final Policy, and any amendments thereto. None of Magenta, any of its Subsidiaries, and to the Knowledge of Magenta, any contract manufacturer with respect to any Magenta Product Candidate, or any of their respective officers, employees or agents is currently or has been debarred, convicted of any crime or is engaging or has engaged in any conduct that could result in a material debarment or exclusion under (i) 21 U.S.C. Section 335a or (ii) any similar applicable Law. To the Knowledge of Magenta, no material debarment or exclusionary claims, actions, proceedings or investigations in respect of their business or products are pending or threatened against Magenta, any of its Subsidiaries, and to the Knowledge of the Magenta, any contract manufacturer with respect to any Magenta Product Candidate, or any of its officers, employees or agents.

(g) All manufacturing operations conducted by, or to the Knowledge of Magenta, for the benefit of, Magenta or its Subsidiaries in connection with any Magenta Product Candidate, since January 1, 2022, have been and are being conducted in compliance in all material respects with applicable Laws, including the FDA’s standards for current good manufacturing practices, including applicable requirements contained in 21 C.F.R. Parts 210 and 211, and the respective counterparts thereof promulgated by Governmental Authorities in countries outside the United States.

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(h) None of Magenta, any of its Subsidiaries, and to the Knowledge of Magenta, any manufacturing site of a contract manufacturer or laboratory, with respect to any Magenta Product Candidate, (i) is subject to a Drug/Device Regulatory Agency shutdown or import or export prohibition or (ii) has received any Form FDA 483, notice of violation, warning letter, untitled letter or similar correspondence or notice from the FDA or other Drug/Device Regulatory Agency alleging or asserting noncompliance with any applicable Law, in each case, that have not been complied with or closed to the satisfaction of the relevant Drug/Device Regulatory Agency, and, to the Knowledge of Magenta, neither the FDA nor any other Drug/Device Regulatory Agency is considering such action.

4.15 Legal Proceedings; Orders.

(a) Except as set forth in Section 4.15 of the Magenta Disclosure Schedule, there is no pending Legal Proceeding and, to the Knowledge of Magenta, no Person has threatened in writing to commence any Legal Proceeding: (i) that involves Magenta or any of its Subsidiaries or any Magenta Associate (in his or her capacity as such) or any of the material assets owned or used by Magenta or any of its Subsidiaries or (ii) that challenges, or that may have the effect of preventing, delaying, making illegal or otherwise interfering with, the Contemplated Transactions.

(b) There is no Order to which Magenta or any of its Subsidiaries, or any of the material assets owned or used by Magenta or any of its Subsidiaries is subject. To the Knowledge of Magenta, no officer or other Magenta Key Employee or any of its Subsidiaries is subject to any Order that prohibits such officer or employee from engaging in or continuing any conduct, activity or practice relating to the business of Magenta or any of its Subsidiaries or to any material assets owned or used by Magenta or any of its Subsidiaries.

4.16 Tax Matters.

(a) Each of Magenta and each of its Subsidiaries has timely filed (or caused to be timely filed) all income Tax Returns and all other material Tax Returns required to be filed by it under applicable Law (taking into account any applicable extensions). All such Tax Returns were true, correct and complete in all material respects. Subject to exceptions as would not be material, no claim has been made by a Governmental Authority in a jurisdiction where Magenta or any of its Subsidiaries does not file Tax Returns that Magenta or any of its Subsidiaries is subject to taxation by that jurisdiction.

(b) All material amounts of Taxes due and owing by Magenta or any of its Subsidiaries (whether or not shown on any Tax Return) have been timely paid (taking into account any applicable extensions).

(c) Each of Magenta and each of its Subsidiaries has withheld and paid to the appropriate Governmental Authority all material Taxes required to have been withheld and paid in connection with any amounts paid or owing to any employee, independent contractor, creditor, stockholder or other third party.

(d) There are no Encumbrances for a material amount of Taxes (other Encumbrances described in clause (a) of the definition of “Permitted Encumbrances”) upon any of the assets of Magenta or any of its Subsidiaries.

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(e) No deficiencies for a material amount of Taxes with respect to Magenta or any of its Subsidiaries have been claimed, proposed or assessed by any Governmental Authority in writing that have not been timely paid in full. There are no pending (or, based on written notice, threatened) material audits, examinations assessments or other actions for or relating to any liability in respect of Taxes of Magenta or any of its Subsidiaries. Neither Magenta nor any of its Subsidiaries has granted a waiver of any statute of limitations in respect of a material amount of Taxes or an extension of time with respect to a material Tax assessment or deficiency that, in each case, is currently in effect.

(f) Neither Magenta nor any of its Subsidiaries is a party to any Tax allocation, Tax sharing or similar agreement (including indemnity arrangements), other than Ordinary Course Agreements.

(g) Neither Magenta nor any of its Subsidiaries has been a member of an affiliated group filing a consolidated U.S. federal income Tax Return (other than a group the common parent of which is Magenta). Neither Magenta nor any of its Subsidiaries has any material Liability for the Taxes of any Person (other than Magenta or its Subsidiaries) under Treasury Regulations Section 1.1502-6 (or any similar provision of state, local, or foreign law), as a transferee or successor, or by Contract (other than an Ordinary Course Agreement).

(h) Neither Magenta nor any of its Subsidiaries has distributed stock of another Person, or has had its stock distributed by another Person, in a transaction that was purported or intended to be governed in whole or in part by Section 355 of the Code or Section 361 of the Code.

(i) Neither Magenta nor any of its Subsidiaries has entered into any transaction identified as a “listed transaction” for purposes of Treasury Regulations Sections 1.6011-4(b)(2) or 301.6111-2(b)(2).

(j) Neither Magenta nor any of its Subsidiaries is aware of any facts or circumstances or has taken or agreed to take any action, in each case, that would reasonably be expected to prevent or impede the Intended Tax Treatment.

4.17 Employee and Labor Matters; Benefit Plans.

(a) Section 4.17(a) of the Magenta Disclosure Schedule sets forth, for each Magenta Associate who is an employee of Magenta or any of its Subsidiaries, such employee’s name, employer, title, hire date, location, whether full- or part-time, whether active or on leave (and, if on leave, the expected return), whether exempt from the Fair Labor Standards Act, annual salary and wage rate, most recent annual bonus received and current annual bonus opportunity. Section 4.17(a) of the Magenta Disclosure Schedule separately sets forth, for each Magenta Associate who is an individual independent contractor engaged by Magenta or any of its Subsidiaries, such contractor’s name, duties and rate of compensation.

(b) The employment of Magenta’s employees is terminable by Magenta at will. Magenta has made available to the Company accurate and complete copies of all employee manuals and handbooks, disclosure materials, policy statements and other materials relating to the employment of Magenta Associates to the extent currently effective and material.

(c) Magenta is not a party to, bound by the terms of, and does not have a duty to bargain under, any collective bargaining agreement or other Contract with a labor organization representing any of its employees, and there are no labor organizations representing or, to the Knowledge of Magenta, purporting to represent or seeking to represent any employees of Magenta.

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(d) Section 4.17(d) of the Magenta Disclosure Schedule lists all Magenta Employee Plans (other than employment arrangements which are terminable “at will” without any contractual obligation on the part of Magenta or any of its Subsidiaries to make any severance, termination, change in control or similar payment and that are substantively identical to the employment arrangements made available to the Company).

(e) Each Magenta Employee Plan that is intended to be qualified under Section 401(a) of the Code has received a favorable determination or opinion letter with respect to such qualified status from the IRS. To the Knowledge of Magenta, nothing has occurred that would reasonably be expected to adversely affect the qualified status of any such Magenta Employee Plan or the exempt status of any related trust.

(f) Each Magenta Employee Plan has been established, maintained and operated in compliance, in all material respects, with its terms all applicable Law, including, without limitation, the Code, ERISA and the Affordable Care Act. No Legal Proceeding (other than those relating to routine claims for benefits) is pending or, to the Knowledge of Magenta, threatened with respect to any Magenta Employee Plan. All payments and/or contributions required to have been made with respect to all Magenta Employee Plans either have been made or have been accrued in accordance with the terms of the applicable Magenta Employee Plan and applicable Law.

(g) Neither Magenta nor any of its ERISA Affiliates maintains, contributes to or is required to contribute to, or has, in the past six (6) years, maintained, contributed to or been required to contribute to (i) any “employee benefit plan” that is or was subject to Title IV or Section 302 of ERISA or Section 412 of the Code, (ii) a Multiemployer Plan, (iii) any funded welfare benefit plan within the meaning of Section 419 of the Code, (iv) any Multiple Employer Plan, or (v) any Multiple Employer Welfare Arrangement. Neither Magenta nor any of its ERISA Affiliates has ever incurred any liability under Title IV of ERISA.

(h) No Magenta Employee Plan provides for medical or other welfare benefits to any service provider beyond termination of service or retirement, other than (1) pursuant to COBRA or an analogous state law requirement or (2) continuation coverage through the end of the month in which such termination or retirement occurs. Magenta does not sponsor or maintain any self-funded medical or long-term disability benefit plan.

(i) No Magenta Employee Plan is subject to any law of a foreign jurisdiction outside of the United States.

(j) Each Magenta Employee Plan that constitutes in any part a “nonqualified deferred compensation plan” (as such term is defined under Section 409A(d)(1) of the Code and the guidance thereunder) (each, a “Magenta 409A Plan”) has been operated and maintained in all material respects in operational and documentary compliance with the requirements of Section 409A of the Code and the applicable guidance thereunder. No payment to be made under any Magenta 409A Plan is or, when made in accordance with the terms of the Magenta 409A Plan, will be subject to the penalties of Section 409A(a)(1) of the Code.

(k) Magenta is in material compliance with all Employment-Related Laws and in each case, with respect to the employees of Magenta: (i) has withheld and reported all material amounts required by law or by agreement to be withheld and reported with respect to wages, salaries and other payments to employees, (ii) is not liable for any material amounts of arrears of wages, severance pay or any Taxes or any penalty for failure to comply with any of the foregoing and (iii) is not liable for any material payment to any trust or other fund governed by or maintained by or on behalf of any Governmental

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Authority, with respect to unemployment compensation benefits, social security or other benefits or obligations for employees (other than routine payments to be made in the Ordinary Course of Business). There are no material Legal Proceedings, claims, labor disputes or organizing activities, or grievances pending or, to the Knowledge of Magenta, threatened or reasonably anticipated against or involving Magenta or any trustee of Magenta relating to any employee, contingent worker, director, employment agreement or Magenta Employee Plan (other than routine claims for benefits) or Employment-Related Laws. To the Knowledge of Magenta, there are no material pending or threatened or reasonably anticipated claims or actions against Magenta, any Magenta trustee or any trustee of any Subsidiary under any workers’ compensation policy or long-term disability policy. Magenta is not a party to a conciliation agreement, consent decree or other agreement or Order with any federal, state or local agency or Governmental Authority with respect to employment practices.

(l) Magenta has no material liability with respect to any misclassification within the past four (4) years of: (i) any Person as an independent contractor rather than as an employee, (ii) any employee leased from another employer or (iii) any employee currently or formerly classified as exempt from overtime wages. Magenta has not taken any action which would constitute a “plant closing” or “mass layoff” within the meaning of the WARN Act, issued any notification of a plant closing or mass layoff required by the WARN Act (nor has Magenta been under any requirement or obligation to issue any such notification), or incurred any liability or obligation under the WARN Act that remains unsatisfied.

(m) There has never been, nor has there been any threat of, any strike, slowdown, work stoppage, lockout, job action, union, organizing activity, question concerning representation or any similar activity or dispute, affecting Magenta. No event has occurred within the past six months, and no condition or circumstance exists, that might directly or indirectly be likely to give rise to or provide a basis for the commencement of any such strike, slowdown, work stoppage, lockout, job action, union organizing activity, question concerning representation or any similar activity or dispute.

(n) Magenta is not, nor has Magenta been, engaged in any material unfair labor practice within the meaning of the National Labor Relations Act. There is no material Legal Proceeding, claim, labor dispute or grievance pending or, to the Knowledge of Magenta, threatened or reasonably anticipated relating to any employment contract, privacy right, labor dispute, wages and hours, leave of absence, plant closing notification, workers’ compensation policy, long-term disability policy, harassment, retaliation, immigration, employment statute or regulation, safety or discrimination matter involving any current or former employee of Magenta, including charges of unfair labor practices or discrimination complaints.

(o) There is no contract, agreement, plan or arrangement to which Magenta or any of its Subsidiaries is a party or by which it is bound to compensate any of its employees or other service providers for any income or excise taxes paid pursuant to the Code, including, but not limited to, Section 4999 or Section 409A of the Code.

(p) Neither Magenta nor any of its Subsidiaries is a party to any Contract that as a result of the execution and delivery of this Agreement, the stockholder approval of this Agreement, nor the consummation of the transactions contemplated hereby, could (either alone or in conjunction with any other event) (i) result in the payment of any “parachute payment” within the meaning of Section 280G of the Code or (ii) result in, or cause the accelerated vesting, payment, funding or delivery of, or increase the amount or value of, any payment or benefit to any employee, officer, director or other service provider of Magenta or any of its Subsidiaries.

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4.18 Environmental Matters. Since January 1, 2022, Magenta and each of its Subsidiaries has complied with all applicable Environmental Laws, which compliance includes the possession by Magenta of all permits and other Governmental Authorizations required under applicable Environmental Laws and compliance with the terms and conditions thereof, except for any failure to be in compliance that, individually or in the aggregate, would not result in a Magenta Material Adverse Effect. Neither Magenta nor any of its Subsidiaries has received since January 1, 2022, any written notice or other communication (in writing or otherwise), whether from a Governmental Authority, citizens group, employee or otherwise, that alleges that Magenta or any of its Subsidiaries is not in compliance with any Environmental Law, and, to the Knowledge of Magenta, there are no circumstances that may prevent or interfere with Magenta’s or any of its Subsidiaries’ compliance with any Environmental Law in the future, except where such failure to comply would not reasonably be expected to have a Magenta Material Adverse Effect. To the Knowledge of Magenta: (i) no current or prior owner of any property leased or controlled by Magenta or any of its Subsidiaries has received since January 1, 2022, any written notice or other communication relating to property owned or leased at any time by Magenta or any of its Subsidiaries, whether from a Governmental Authority, citizens group, employee or otherwise, that alleges that such current or prior owner or Magenta or any of its Subsidiaries is not in compliance with or violated any Environmental Law relating to such property and (ii) neither Magenta nor any of its Subsidiaries has any material liability under any Environmental Law.

4.19 Insurance. Magenta has made available to the Company accurate and complete copies of all material insurance policies and all material self-insurance programs and arrangements relating to the business, assets, liabilities and operations of Magenta and its Subsidiaries (including Merger Sub). Each of such insurance policies is in full force and effect and Magenta and its Subsidiaries (including Merger Sub) are in compliance in all material respects with the terms thereof. Other than customary end of policy notifications from insurance carriers, since January 1, 2022, neither Magenta nor any of its Subsidiaries has received any notice or other communication regarding any actual or possible: (i) cancellation or invalidation of any insurance policy or (ii) refusal or denial of any coverage, reservation of rights or rejection of any material claim under any insurance policy. Each of Magenta and its Subsidiaries (including Merger Sub) has provided timely written notice to the appropriate insurance carrier(s) of each Legal Proceeding pending against Magenta or such Subsidiary for which Magenta or such Subsidiary has insurance coverage, and no such carrier has issued a denial of coverage or a reservation of rights with respect to any such Legal Proceeding, or informed Magenta or any of its Subsidiaries of its intent to do so.

4.20 Transactions with Affiliates. Except as set forth in the Magenta SEC Documents filed prior to the date of this Agreement, since the date of Magenta’s last proxy statement filed in 2022 with the SEC, no event has occurred that would be required to be reported by Magenta pursuant to Item 404 of Regulation S-K promulgated by the SEC. Section 4.20 of the Magenta Disclosure Schedule identifies each Person who is (or who may be deemed to be) an Affiliate of Magenta as of the date of this Agreement.

4.21 No Financial Advisors. Except as set forth on Section 4.21 of the Magenta Disclosure Schedule, no broker, finder or investment banker is entitled to any brokerage fee, finder’s fee, opinion fee, success fee, transaction fee or other fee or commission in connection with the Contemplated Transactions based upon arrangements made by or on behalf of Magenta.

4.22 Valid Issuance. The Magenta Common Stock to be issued in the Merger will, when issued in accordance with the provisions of this Agreement, be validly issued, fully paid and nonassessable.

4.23 Privacy and Data Security. Magenta and its Subsidiaries have complied with all applicable Privacy Laws and the applicable terms of any Magenta Contracts relating to privacy, security, collection or use of Personal Information of any individuals (including clinical trial participants, patients, patient family members, caregivers or advocates, physicians and other health care professionals, clinical trial investigators, researchers, pharmacists) that interact with Magenta or any of its Subsidiaries in connection with the operation of Magenta’s and its Subsidiaries’ business, except for such noncompliance as has not had, and would not reasonably be expected to have, individually or in the aggregate, a Magenta Material Adverse Effect. To the Knowledge of Magenta, Magenta has implemented and maintains reasonable Privacy Policies and has complied with its Privacy Policies, except for such noncompliance as has not to the Knowledge of the Magenta had, and would not reasonably be expected to have, individually or in the aggregate, a Magenta Material Adverse Effect. To the Knowledge of Magenta, as of the date

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hereof, no claims have been asserted or threatened against Magenta by any Person alleging a violation of Privacy Laws, Privacy Policies and/or the applicable terms of any Magenta Contracts relating to privacy, security, collection or use of Personal Information of any individuals. To the Knowledge of Magenta, there have been no data security incidents, personal data breaches or other adverse events or incidents related to Personal Information or Magenta data in the custody or control of Magenta or any service provider acting on behalf of Magenta, in each case where such incident, breach or event would result in a notification obligation to any Person under applicable law or pursuant to the terms of any Magenta Contract.

4.24 No Other Representations or Warranties. Magenta hereby acknowledges and agrees that, except for the representations and warranties contained in this Agreement, neither the Company nor any of its Subsidiaries nor any other person on behalf of the Company or its Subsidiaries makes any express or implied representation or warranty with respect to the Company or its Subsidiaries or with respect to any other information provided to Magenta, Merger Sub or stockholders or any of their respective Affiliates in connection with the Contemplated Transactions, and (subject to the express representations and warranties of the Company set forth in Section 3 (in each case as qualified and limited by the Company Disclosure Schedule)) none of Magenta, Merger Sub nor any of their respective Representatives or stockholders, has relied on any such information (including the accuracy or completeness thereof).

Section 5. Certain Covenants of the Parties.

5.1 Operation of Magenta’s Business.

(a) Except (i) as expressly contemplated or permitted by this Agreement, (ii) as set forth on Section 5.1(a) of the Magenta Disclosure Schedule, (iii) as required by applicable Law, or (iv) unless the Company shall otherwise consent in writing (which consent shall not be unreasonably withheld, delayed or conditioned), during the period commencing on the date of this Agreement and continuing until the earlier to occur of the termination of this Agreement pursuant to Section 10 and the Effective Time (the “Pre-Closing Period”), Magenta shall, and shall cause its Subsidiaries to, use commercially reasonable efforts to (x) conduct its business and operations in the Ordinary Course of Business and in material compliance with all applicable Law and the requirements of all Contracts that constitute Magenta Material Contracts and (y) continue to pay material outstanding accounts payable and other material current Liabilities (including payroll) when due and payable.

(b) Except (i) as expressly contemplated or permitted by this Agreement, (ii) as set forth in Section 5.1(b) of the Magenta Disclosure Schedule, (iii) as required by applicable Law, or (iv) with the prior written consent of the Company (which consent shall not be unreasonably withheld, delayed or conditioned), at all times during the Pre-Closing Period, Magenta shall not, nor shall it cause or permit any of Subsidiaries to, do any of the following:

(i) declare, accrue, set aside or pay any dividend or make any other distribution in respect of any shares of its capital stock or repurchase, redeem or otherwise reacquire any shares of its capital stock or other securities, including Magenta Rights (except for shares of Magenta Common Stock from terminated employees, directors or consultants of Magenta);

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(ii) sell, issue, grant, pledge or otherwise dispose of or encumber or authorize the issuance of: (A) any capital stock or other security (except for Magenta Common Stock issued upon the valid exercise or settlement of outstanding Magenta Options or Magenta Restricted Stock Units, as applicable), (B) any option, warrant or right to acquire any capital stock or any other security or (C) any instrument convertible into or exchangeable for any capital stock or other security;

(iii) except as required to give effect to anything in contemplation of the Closing, amend any of its Organizational Documents or the Rights Agreement, or effect or be a party to any merger, consolidation, share exchange, business combination, recapitalization, reclassification of shares, stock split, reverse stock split or similar transaction except, for the avoidance of doubt, the Contemplated Transactions;

(iv) form any Subsidiary or acquire any equity interest or other interest in any other Entity or enter into a joint venture with any other Entity;

(v) (A) lend money to any Person, (B) incur or guarantee any indebtedness for borrowed money, (C) guarantee any debt securities of others or (D) make any capital expenditure or commitment;

(vi) (A) adopt, establish or enter into any Magenta Employee Plan, including, for avoidance of doubt, any equity awards plans, (B) cause or permit any Magenta Employee Plan to be amended other than as required by law or in order to make amendments for the purposes of compliance with Section 409A of the Code, (C) pay any bonus or make any profit-sharing or similar payment to (except with respect to obligations in place on the date of this Agreement pursuant to any Magenta Employee Plan disclosed to the Company), or increase the amount of the wages, salary, commissions, fringe benefits or other compensation or remuneration payable to, any of its directors, officers, employees or consultants, (D) increase the severance or change of control benefits offered to any current or new employees, directors or consultants, or (E) hire any officer, employee or consultant;

(vii) enter into any material transaction outside the Ordinary Course of Business;

(viii) acquire any material asset or sell, lease, license or otherwise irrevocably dispose of any of its assets or properties, or grant any Encumbrance with respect to such assets or properties;

(ix) other than in the Ordinary Course of Business: (A) make, change or revoke any material Tax election; (B) file any amended income or other material Tax Return; (C) adopt or change any material accounting method in respect of Taxes; (D) enter into any material Tax closing agreement, settle any material Tax claim or assessment; (E) consent to any extension or waiver of the limitation period applicable to or relating to any material Tax claim or assessment; or (F) surrender any material claim for refund;

(x) waive, settle or compromise any pending or threatened Legal Proceeding against Magenta or any of its Subsidiaries, other than waivers, settlements or agreements (A) for an amount not in excess of $100,000 in the aggregate (excluding amounts to be paid under existing insurance policies or renewals thereof) and (B) that do not impose any material restrictions on the operations or businesses of Magenta or its Subsidiaries, taken as a whole, or any equitable relief on, or the admission of wrongdoing by Magenta or any of its Subsidiaries;

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(xi) delay or fail to repay when due any material obligation, including accounts payable and accrued expenses (provided, however, that any such accounts payable or accrued expenses need not be paid if the validity or amount thereof shall at the time be contested in good faith);

(xii) forgive any loans to any Person, including its employees, officers, directors or Affiliate;

(xiii) terminate or modify in any material respect, or fail to exercise renewal rights with respect to, any material insurance policy;

(xiv) (A) materially change pricing or royalties or other payments set or charged by Magenta or any of Subsidiaries to its customers or licensees or (B) agree to materially change pricing or royalties or other payments set or charged by Persons who have licensed Intellectual Property to Magenta or any of Subsidiaries;

(xv) enter into, amend or terminate any Magenta Material Contract; or

(xvi) agree, resolve or commit to do any of the foregoing.

Nothing contained in this Agreement shall give the Company, directly or indirectly, the right to control or direct the operations of Magenta prior to the Effective Time. Prior to the Effective Time, Magenta shall exercise, consistent with the terms and conditions of this Agreement, complete unilateral control and supervision over its business operations.

(c) Notwithstanding any provision herein to the contrary (including the foregoing provisions of this Section 5.1), Magenta may engage in the sale, license, transfer, disposition, divestiture or other monetization transaction (i.e., a royalty transaction) or winding down of the Magenta Legacy Business or the sale, license, transfer, disposition, divestiture or other monetization transaction (i.e., a royalty transaction) or other disposition of any Magenta Legacy Business (each, an “Magenta Legacy Transaction”); provided, however, that to the extent any Magenta Legacy Transaction results in material obligations of Magenta that will extend beyond Closing, such terms shall be reasonably acceptable to Company.

5.2 Operation of the Company’s Business.

(a) Except (i) as expressly contemplated or permitted by this Agreement, including the Subscription Agreement, (ii) as set forth in Section 5.2(a) of the Company Disclosure Schedule, (iii) as required by applicable Law, or (iv) unless Magenta shall otherwise consent in writing (which consent shall not be unreasonably withheld, delayed or conditioned), during the Pre-Closing Period the Company shall, and shall cause its Subsidiaries to, use commercially reasonable efforts to conduct its business and operations in the Ordinary Course of Business and in material compliance with all applicable Law and the requirements of all Contracts that constitute Company Material Contracts.

(b) Except (i) as expressly contemplated or permitted by this Agreement, including the Subscription Agreement, (ii) as set forth in Section 5.2(b) of the Company Disclosure Schedule, (iii) as required by applicable Law, or (iv) with the prior written consent of Magenta (which consent shall not be unreasonably withheld, delayed or conditioned), at all times during the Pre-Closing Period, the Company shall not, nor shall it cause or permit any of its Subsidiaries to, do any of the following:

(i) declare, accrue, set aside or pay any dividend or make any other distribution in respect of any shares of capital stock; or repurchase, redeem or otherwise reacquire any shares of Company Capital Stock or other securities (except for shares of Company Common Stock from terminated employees, directors or consultants of the Company);

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(ii) except as required to give effect to anything in contemplation of the Closing, amend any of its or its Subsidiaries’ Organizational Documents, or effect or be a party to any merger, consolidation, share exchange, business combination, recapitalization, reclassification of shares, stock split, reverse stock split or similar transaction except, for the avoidance of doubt, the Contemplated Transactions;

(iii) sell, issue, grant, pledge or otherwise dispose of or encumber or authorize any of the foregoing actions with respect to: (A) any capital stock or other security of the Company or any of its Subsidiaries (except for shares of outstanding Company Common Stock issued upon the valid exercise of Company Options or Company Warrants), (B) any option, warrant or right to acquire any capital stock or any other security or (C) any instrument convertible into or exchangeable for any capital stock or other security of the Company or any of its Subsidiaries;

(iv) form any Subsidiary or acquire any equity interest or other interest in any other Entity or enter into a joint venture with any other Entity;

(v) (A) lend money to any Person, (B) incur or guarantee any indebtedness for borrowed money, (C) guarantee any debt securities of others or (D) make any capital expenditure or commitment in excess of $100,000;

(vi) other than in the Ordinary Course of Business: (A) adopt, establish or enter into any Company Employee Plan, including, for the avoidance of doubt, any equity awards plans, (B) cause or permit any Company Employee Plan to be amended other than as required by law or in order to make amendments for the purposes of compliance with Section 409A of the Code, (C) pay any material bonus or make any material profit-sharing or similar payment to (except with respect to obligations in place on the date of this Agreement pursuant to any Company Employee Plan disclosed to Magenta), or materially increase the amount of the wages, salary, commissions, fringe benefits or other compensation or remuneration payable to, any of its directors, officers or employees, (D) increase the severance or change of control benefits offered to any current or new employees, directors or consultants, or (E) hire, engage or appoint any individual who may reasonably be deemed to be an “executive officer” as defined under the Exchange Act; provided, that the Company may, in its sole discretion, replace a departing executive officer, other than its Chief Executive Officer, Chief Financial Officer or Chief Medical Officer;

(vii) enter into any material transaction outside the Ordinary Course of Business;

(viii) acquire any material asset or sell, lease, license or otherwise irrevocably dispose of any of its assets or properties, or grant any Encumbrance with respect to such assets or properties, except in the Ordinary Course of Business;

(ix) sell, assign, transfer, license, sublicense or otherwise dispose of any material Company IP Rights (other than pursuant to non-exclusive licenses in the Ordinary Course of Business);

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(x) other than in the Ordinary Course of Business: (A) make, change or revoke any material Tax election; (B) file any amended income or other material Tax Return; (C) adopt or change any material accounting method in respect of Taxes; (D) enter into any material Tax closing agreement, settle any material Tax claim or assessment; (E) consent to any extension or waiver of the limitation period applicable to or relating to any material Tax claim or assessment; or (F) surrender any material claim for refund;

(xi) waive, settle or compromise any pending or threatened Legal Proceeding against the Company, other than waivers, settlements or agreements (A) for an amount not in excess of $100,000 in the aggregate (excluding amounts to be paid under existing insurance policies or renewals thereof) and (B) that do not impose any material restrictions on the operations or businesses of the Company or any equitable relief on, or the admission of wrongdoing by the Company;

(xii) delay or fail to repay when due any material obligation, including accounts payable and accrued expenses, other than in the Ordinary Course of Business;

(xiii) forgive any loans to any Person, including its employees, officers, directors or Affiliate;

(xiv) sell, assign, transfer, license, sublicense or otherwise dispose of any material Company IP Rights (other than in the Ordinary Course of Business);

(xv) terminate or modify in any material respect, or fail to exercise renewal rights with respect to, any material insurance policy;

(xvi) enter into, amend or terminate any Company Material Contract;

(xvii) (A) materially change pricing or royalties or other payments set or charged by the Company or any of its Subsidiaries to its customers or licensees or (B) agree to materially change pricing or royalties or other payments set or charged by Persons who have licensed Intellectual Property to the Company or any of its Subsidiaries; or

(xviii) agree, resolve or commit to do any of the foregoing.

Nothing contained in this Agreement shall give Magenta, directly or indirectly, the right to control or direct the operations of the Company prior to the Effective Time. Prior to the Effective Time, the Company shall exercise, consistent with the terms and conditions of this Agreement, complete unilateral control and supervision over its business operations.

5.3 Access and Investigation.

(a) Subject to the terms of the Confidentiality Agreement, which the Parties agree will continue in full force following the date of this Agreement, during the Pre-Closing Period, upon reasonable notice, Magenta, on the one hand, and the Company, on the other hand, shall and shall use commercially reasonable efforts to cause such Party’s Representatives to: (a) provide the other Party and such other Party’s Representatives with reasonable access during normal business hours to such Party’s Representatives, personnel, property and assets and to all existing books, records, Tax Returns, work papers and other documents and information relating to such Party and its Subsidiaries, (b) provide the other Party and such other Party’s Representatives with such copies of the existing books, records, Tax Returns, work papers, product data, and other documents and information relating to such Party and its Subsidiaries, and with such additional financial, operating and other data and information regarding such Party and its Subsidiaries as the other Party may reasonably request, (c) permit the other Party’s officers and other employees to meet, upon reasonable notice and during normal business hours, with the chief financial officer and other officers and managers of such Party responsible for such Party’s financial statements and

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the internal controls of such Party to discuss such matters as the other Party may deem necessary, and (d) make available to the other Party copies of any material notice, report or other document filed with or sent to or received from any Governmental Authority in connection with the Contemplated Transactions. Any investigation conducted by either Magenta or the Company pursuant to this Section 5.3 shall be conducted in such manner as not to interfere unreasonably with the conduct of the business of the other Party.

(b) Notwithstanding anything herein to the contrary in this Section 5.3, no access or examination contemplated by this Section 5.3 shall be permitted to the extent that it would require any Party or its Subsidiaries to waive the attorney-client privilege or attorney work product privilege, or violate any applicable Law; provided, that such Party or its Subsidiary (i) shall be entitled to withhold only such information that may not be provided without causing such violation or waiver, (ii) shall provide to the other Party all related information that may be provided without causing such violation or waiver (including, to the extent permitted, redacted versions of any such information) and (iii) shall enter into such effective and appropriate joint-defense agreements or other protective arrangements as may be reasonably requested by the other Party in order that all such information may be provided to the other Party without causing such violation or waiver.

5.4 No Solicitation.

(a) Each of Magenta and the Company agrees that, during the Pre-Closing Period, neither it nor any of its Subsidiaries shall, nor shall it or any of its Subsidiaries authorize any of its Representatives to, directly or indirectly: (i) solicit, initiate or knowingly encourage, induce or facilitate the communication, making, submission or announcement of any Acquisition Proposal or Acquisition Inquiry or take any action that could reasonably be expected to lead to an Acquisition Proposal or Acquisition Inquiry, (ii) furnish any non-public information regarding such Party to any Person in connection with or in response to an Acquisition Proposal or Acquisition Inquiry, (iii) engage in discussions or negotiations with any Person with respect to any Acquisition Proposal or Acquisition Inquiry, (iv) approve, endorse or recommend any Acquisition Proposal (subject to Section 6.2 and Section 6.3), (v) execute or enter into any letter of intent or any Contract contemplating or otherwise relating to any Acquisition Transaction, (vi) take any action that would reasonably be expected to lead to an Acquisition Proposal or Acquisition Inquiry or (vii) publicly propose to do any of the following; provided, however, that, notwithstanding anything contained in this Section 5.4 and subject to compliance with this Section 5.4, prior to the approval of this Agreement by a Party’s stockholders (i.e., the Required Company Stockholder Vote, in the case of the Company and its Subsidiaries, or the Required Magenta Stockholder Vote in the case of Magenta), such Party may furnish non-public information regarding such Party and its Subsidiaries to, and enter into discussions or negotiations with, any Person in response to a bona fide written Acquisition Proposal by such Person which such Party’s board of directors determines in good faith, after consultation with such Party’s financial advisors and outside legal counsel, constitutes, or is reasonably likely to result in, a Superior Offer (and is not withdrawn) if: (A) neither such Party nor any Representative of such Party shall have breached this Section 5.4 in any material respect, (B) the board of directors of such Party concludes in good faith based on the advice of outside legal counsel, that the failure to take such action would reasonably be expected to be inconsistent with the board of directors’ fiduciary duties under applicable Law, (C) at least two (2) Business Days prior to initially furnishing any such nonpublic information to, or entering into discussions with, such Person, such Party gives the other Party written notice of the identity of such Person and of such Party’s intention to furnish nonpublic information to, or enter into discussions with, such Person, (D) such Party receives from such Person an executed Acceptable Confidentiality Agreement and (E) at least two (2) Business Days prior to furnishing any such nonpublic

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information to such Person, such Party furnishes such nonpublic information to the other Party (to the extent such information has not been previously furnished by such Party to the other Party). Without limiting the generality of the foregoing, each Party acknowledges and agrees that, in the event any Representative of such Party takes any action that, if taken by such Party, would constitute a breach of this Section 5.4 by such Party, the taking of such action by such Representative shall be deemed to constitute a breach of this Section 5.4 by such Party for purposes of this Agreement.

(b) If any Party or any Representative of such Party receives an Acquisition Proposal or Acquisition Inquiry at any time during the Pre-Closing Period, then such Party shall promptly (and in no event later than one (1) Business Day after such Party becomes aware of such Acquisition Proposal or Acquisition Inquiry) advise the other Party orally and in writing of such Acquisition Proposal or Acquisition Inquiry (including the identity of the Person making or submitting such Acquisition Proposal or Acquisition Inquiry, and the terms thereof). Such Party shall keep the other Party reasonably informed with respect to the status and terms of any such Acquisition Proposal or Acquisition Inquiry and any material modification or material proposed modification thereto.

(c) Each Party shall immediately cease and cause to be terminated any existing discussions, negotiations and communications with any Person that relate to any Acquisition Proposal or Acquisition Inquiry as of the date of this Agreement and request the destruction or return of any nonpublic information provided to such Person.

5.5 Notification of Certain Matters. During the Pre-Closing Period, each of the Company, on the one hand, and Magenta, on the other hand, shall promptly notify the other (and, if in writing, furnish copies of) if any of the following occurs: (a) any notice or other communication is received from any Person alleging that the Consent of such Person is or may be required in connection with any of the Contemplated Transactions, (b) any Legal Proceeding against or involving or otherwise affecting such Party or its Subsidiaries is commenced, or, to the Knowledge of such Party, threatened against such Party or, to the Knowledge of such Party, any director, officer or Key Employee of such Party, (c) such Party becomes aware of any inaccuracy in any representation or warranty made by such Party in this Agreement or (d) the failure of such Party to comply with any covenant or obligation of such Party; in each case that could reasonably be expected to make the timely satisfaction of any of the conditions set forth in Section 7, Section 8 or Section 9, as applicable, impossible or materially less likely. No such notice shall be deemed to supplement or amend the Company Disclosure Schedule or the Magenta Disclosure Schedule for the purpose of (x) determining the accuracy of any of the representations and warranties made by the Company in this Agreement or (y) determining whether any condition set forth in Section 7, Section 8 or Section 9 has been satisfied. Any failure by either Party to provide notice pursuant to this Section 5.5 shall not be deemed to be a breach for purposes of Section 8.2 or Section 9.2, as applicable, unless such failure to provide such notice was knowing and intentional.

Section 6. Additional Agreements of the Parties.

6.1 Registration Statement, Proxy Statement.

(a) As promptly as practicable after the date of this Agreement, (i) Magenta shall prepare and file with the SEC a proxy statement relating to the Magenta Stockholder Meeting to be held in connection with the Merger (together with any amendments thereof or supplements thereto, the “Proxy Statement”) and (ii) Magenta, in cooperation with the Company, shall prepare and file with the SEC a registration statement on Form S-4 (the “Form S-4”), in which the Proxy Statement shall be included as a part (the Proxy Statement and the Form S-4, collectively, the “Registration Statement”), in connection with the registration under the Securities Act of the shares of Magenta Common Stock to be issued by virtue of the Contemplated Transactions. Magenta shall use commercially reasonable efforts to (i) cause the

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Registration Statement to comply with applicable rules and regulations promulgated by the SEC, (ii) cause the Registration Statement to become effective as promptly as practicable, (iii) respond promptly to any comments or requests of the SEC or its staff related to the Registration Statement. Magenta shall take all or any action required under any applicable federal, state, securities and other Laws in connection with the issuance of shares of Magenta Common Stock pursuant to the Contemplated Transactions. Each of the Parties shall reasonably cooperate with the other Party and furnish all information concerning itself and their Affiliates, as applicable, to the other Parties that is required by law to be included in the Registration Statement as the other Parties may reasonably request in connection with such actions and the preparation of the Registration Statement and Proxy Statement.

(b) Magenta covenants and agrees that the Registration Statement (and the letter to stockholders, notice of meeting and form of proxy included therewith) will (i) comply as to form in all material respects with the requirements of applicable U.S. federal securities laws and the DGCL, and (ii) will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements made therein, in light of the circumstances under which they were made, not misleading. The Company covenants and agrees that the information supplied by or on behalf of the Company to Magenta for inclusion in the Registration Statement (including the Company Balance Sheet) will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make such information, in light of the circumstances under which they were made, not misleading. Notwithstanding the foregoing, neither Party makes any covenant, representation or warranty with respect to statements made in the Registration Statement (and the letter to stockholders, notice of meeting and form of proxy included therewith), if any, based on information provided by the other Party or any of its Representatives regarding such other Party or its Affiliates for inclusion therein.

(c) Magenta shall use commercially reasonable efforts to cause the Proxy Statement to be mailed to Magenta’s stockholders as promptly as practicable after the Registration Statement is declared effective under the Securities Act. If at any time before the Effective Time, (i) Magenta, Merger Sub or the Company (A) become aware of any event or information that, pursuant to the Securities Act or the Exchange Act, should be disclosed in an amendment or supplement to the Registration Statement or Proxy Statement, (B) receives notice of any SEC request for an amendment or supplement to the Registration Statement or for additional information related thereto, or (C) receives SEC comments on the Registration Statement, or (ii) the information provided in the Registration Statement has become “stale” and new information should be disclosed in an amendment or supplement to the Registration Statement, as the case may be, then such Party, as the case may be, shall promptly inform the other Parties thereof and shall cooperate with such other Parties in Magenta filing such amendment or supplement with the SEC (and, if appropriate, in mailing such amendment or supplement to the Magenta stockholders) or otherwise addressing such SEC request or comments and each Party and shall use their commercially reasonable efforts to cause any such amendment to become effective, if required. Magenta shall promptly notify the Company if it becomes aware (1) that the Registration Statement has become effective, (2) of the issuance of any stop order or suspension of the qualification or registration of the Magenta Common Stock issuable in connection with the Contemplated Transactions for offering or sale in any jurisdiction, or (3) any order of the SEC related to the Registration Statement, and shall promptly provide to the Company copies of all written correspondence between it or any of its Representatives, on the one hand, and the SEC or staff of the SEC, on the other hand, with respect to the Registration Statement and all orders of the SEC relating to the Registration Statement.

(d) The Company shall reasonably cooperate with Magenta and provide, and cause its Representatives to provide, Magenta and its Representatives, with all true, correct and complete information regarding the Company that is required by Law to be included in the Registration Statement or reasonably requested by Magenta to be included in the Registration Statement (collectively, the “Company

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Required S-4 Information”). Without limiting the foregoing, the Company will use commercially reasonable efforts to cause to be delivered to Magenta a consent letter of the Company’s independent accounting firm, dated no more than two (2) Business Days before the date on which the Registration Statement is filed with the SEC (and reasonably satisfactory in form and substance to Magenta), that is customary in scope and substance for consent letters delivered by independent public accountants in connection with registration statements similar to the Registration Statement. The Company and its legal counsel shall be given reasonable opportunity to review and comment on the Registration Statement, including all amendments and supplements thereto, prior to the filing thereof with the SEC, and on the response to any comments of the SEC on the Registration Statement, prior to the filing thereof with the SEC. Magenta may file the Registration Statement, or any amendment or supplement thereto, without the prior consent of the Company, provided that Magenta has included the Company Required S-4 Information in the Registration Statement in substantially the same form as it was provided to Magenta by the Company pursuant to this Section 6.1; provided, further, that if the prior consent of the Company is not obtained then, notwithstanding anything else herein, the Company makes no covenant or representation regarding the portion of such information supplied by or on behalf of the Company to Magenta for inclusion in such Registration Statement that the Company reasonably identifies prior to such filing of the Registration Statement.

(e) As promptly as reasonably practicable following the date of this Agreement, the Company will use commercially reasonable efforts to furnish to Magenta (i) audited financial statements for each of its fiscal years required to be included in the Registration Statement (the “Company Audited Financial Statements”) and (ii) unaudited interim financial statements for each interim period completed prior to Closing that would be required to be included in the Registration Statement or any periodic report due prior to the Closing if the Company were subject to the periodic reporting requirements under the Securities Act or the Exchange Act (the “Company Interim Financial Statements”). Each of the Company Audited Financial Statements and the Company Interim Financial Statements will be suitable for inclusion in the Registration Statement and prepared in accordance with GAAP as applied on a consistent basis during the periods involved (except in each case as described in the notes thereto) and on that basis will present fairly, in all material respects, the financial position and the results of operations, changes in stockholders’ equity and cash flows of the Company as of the dates of and for the periods referred to in the Company Audited Financial Statements or the Company Interim Financial Statements, as the case may be.

6.2 Company Stockholder Written Consent.

(a) Promptly after the Registration Statement has been declared effective under the Securities Act, and in any event no later than two (2) Business Days thereafter, the Company shall obtain the approval by written consent from Company stockholders sufficient for the Required Company Stockholder Vote in lieu of a meeting pursuant to Section 228 of the DGCL, for purposes of (i) adopting and approving this Agreement and the Contemplated Transactions, (ii) acknowledging that the approval given thereby is irrevocable and that such stockholder is aware of its rights to demand appraisal for its shares pursuant to Section 262 of the DGCL, a copy of which will be attached thereto, and that such stockholder has received and read a copy of Section 262 of the DGCL and (iii) acknowledging that by its approval of the Merger it is not entitled to appraisal rights with respect to its shares in connection with the Merger and thereby waives any rights to receive payment of the fair value of its capital stock under the DGCL (the “Company Stockholder Written Consents”). Under no circumstances shall the Company assert that any other approval or consent is necessary by its stockholders to approve this Agreement and the Contemplated Transactions.

(b) Reasonably promptly following receipt of the Required Company Stockholder Vote, the Company shall prepare and mail a notice (the “Stockholder Notice”) to every stockholder of the Company that did not execute the Company Stockholder Written Consent. The Stockholder Notice shall (i) be a statement to the effect that the Company Board determined that the Merger is advisable in accordance with Section 251(b) of the DGCL and in the best interests of the stockholders of the Company and approved and adopted this Agreement, the Merger and the other Contemplated

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Transactions, (ii) provide the stockholders of the Company to whom it is sent with notice of the actions taken in the Company Stockholder Written Consent, including the adoption and approval of this Agreement, the Merger and the other Contemplated Transactions in accordance with Section 228(e) of the DGCL and the certificate of incorporation and bylaws of the Company and (iii) include a description of the appraisal rights of the Company’s stockholders available under the DGCL, along with such other information as is required thereunder and pursuant to applicable Law. All materials (including any amendments thereto) submitted to the stockholders of the Company in accordance with this Section 6.2(b) shall be subject to Magenta’s advance review and reasonable approval.

(c) The Company agrees that, subject to Section 6.2(d): (i) the Company Board shall recommend that the Company’s stockholders vote to adopt and approve this Agreement and the Contemplated Transactions and shall use commercially reasonable efforts to solicit such approval within the time set forth in Section 6.2(a) (the recommendation of the Company Board that the Company’s stockholders vote to adopt and approve this Agreement being referred to as the “Company Board Recommendation”) and (ii) the Company Board Recommendation shall not be withdrawn or modified (and the Company Board shall not publicly propose to withdraw or modify the Company Board Recommendation) in a manner adverse to Magenta, and no resolution by the Company Board or any committee thereof to withdraw or modify the Company Board Recommendation in a manner adverse to Magenta or to adopt, approve or recommend (or publicly propose to adopt, approve or recommend) any Acquisition Proposal shall be adopted or proposed.

(d) Notwithstanding anything to the contrary contained in Section 6.2(c), and subject to compliance with Section 5.4 and Section 6.2, if at any time prior to approval and adoption of this Agreement by the Required Company Stockholder Vote, the Company receives a bona fide written Superior Offer, the Company Board may withhold, amend, withdraw or modify the Company Board Recommendation (or publicly propose to withhold, amend, withdraw or modify the Company Board Recommendation) in a manner adverse to Magenta (collectively, a “Company Board Adverse Recommendation Change”) if, but only if, following the receipt of and on account of such Superior Offer, (i) the Company Board determines in good faith, based on the advice of its outside legal counsel, that the failure to withhold, amend, withdraw or modify such recommendation would reasonably be expected to be inconsistent with its fiduciary duties under applicable Law, (ii) the Company has during the Notice Period (as defined below), negotiated with Magenta in good faith to make such adjustments to the terms and conditions of this Agreement so that such Acquisition Proposal ceases to constitute a Superior Offer and (iii) if after Magenta shall have delivered to the Company a written offer to alter the terms or conditions of this Agreement during the Notice Period, the Company Board shall have determined in good faith, based on the advice of its outside legal counsel, that the failure to withhold, amend, withdraw or modify the Company Board Recommendation would reasonably be expected to be inconsistent with its fiduciary duties under applicable Law (after taking into account such alterations of the terms and conditions of this Agreement); provided that (x) Magenta receives written notice from the Company confirming that the Company Board has determined to change its recommendation at least four (4) Business Days in advance of the Company Board Adverse Recommendation Change (the “Notice Period”), which notice shall include a description in reasonable detail of the reasons for such Company Board Adverse Recommendation Change, and written copies of any relevant proposed transaction agreements with any party making a potential Superior Offer, (y) during any Notice Period, Magenta shall be entitled to deliver to the Company one or more counterproposals to such Acquisition Proposal and the Company will, and cause its Representatives to, negotiate with Magenta in good faith (to the extent Magenta desires to negotiate) to make such adjustments in the terms and conditions of this Agreement so that the applicable Acquisition

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Proposal ceases to constitute a Superior Offer and (z) in the event of any material amendment to any Superior Offer (including any revision in the amount, form or mix of consideration the Company’s stockholders would receive as a result of such potential Superior Offer), the Company shall be required to provide Magenta with notice of such material amendment and the Notice Period shall be extended, if applicable, to ensure that at least three (3) Business Days remain in the Notice Period following such notification during which the parties shall comply again with the requirements of this Section 6.2(d) and the Company Board shall not make a Company Board Adverse Recommendation Change prior to the end of such Notice Period as so extended (it being understood that there may be multiple extensions).

(e) The Company’s obligation to solicit the consent of its stockholders to sign the Company Stockholder Written Consent in accordance with Section 6.2(a) shall not be limited or otherwise affected by the commencement, disclosure, announcement or submission of any Superior Offer or other Acquisition Proposal, or by any Company Board Adverse Recommendation Change.

6.3 Magenta Stockholder Meeting.

(a) Magenta shall take all action necessary under applicable Law to call, give notice of and hold a meeting of the holders of Magenta Common Stock to consider and vote to approve this Agreement and thereby approve the Contemplated Transactions and against any competing proposals pursuant to the terms of this Agreement and, if deemed necessary by the Parties, an amendment to Magenta’s certificate of incorporation to effect the Nasdaq Reverse Split (collectively, the “Magenta Stockholder Matters” and such meeting, the “Magenta Stockholder Meeting”). The Magenta Stockholder Meeting shall be held as promptly as practicable after the date that the Registration Statement is declared effective under the Securities Act, and in any event, no later than 45 days after the effective date of the Registration Statement. Magenta shall take reasonable measures to ensure that all proxies solicited in connection with the Magenta Stockholder Meeting are solicited in compliance with all applicable Law. Notwithstanding anything to the contrary contained herein, if on the date of the Magenta Stockholder Meeting, or a date preceding the date on which the Magenta Stockholder Meeting is scheduled, Magenta reasonably believes that (i) it will not receive proxies sufficient to obtain the Required Magenta Stockholder Vote, whether or not a quorum would be present or (ii) it will not have sufficient shares of Magenta Common Stock represented (whether in person or by proxy) to constitute a quorum necessary to conduct the business of the Magenta Stockholder Meeting, Magenta may postpone or adjourn, or make one or more successive postponements or adjournments of, the Magenta Stockholder Meeting as long as the date of the Magenta Stockholder Meeting is not postponed or adjourned more than an aggregate of 30 days in connection with any postponements or adjournments.

(b) Magenta agrees that (i) the Magenta Board shall recommend that the holders of Magenta Common Stock vote to approve the Magenta Stockholder Matters and shall use commercially reasonable efforts to solicit such approval within the timeframe set forth in Section 6.3(a) above and (ii) the Proxy Statement shall include a statement to the effect that the Magenta Board recommends that Magenta’s stockholders vote to approve the Magenta Stockholder Matters (the recommendation of the Magenta Board being referred to as the “Magenta Board Recommendation”).

(c) Notwithstanding anything to the contrary contained in Section 6.3(b), and subject to compliance with Section 5.4 and Section 6.3, if at any time prior to approval and adoption of this Agreement by the Required Magenta Stockholder Vote, Magenta receives a bona fide written Superior Offer, the Magenta Board may withhold, amend, withdraw or modify the Magenta Board Recommendation (or publicly propose to withhold, amend, withdraw or modify the Magenta Board Recommendation) in a manner adverse to the Company (collectively, a “Magenta Board Adverse Recommendation Change”) if, but only if, following the receipt of and on account of such Superior Offer, (i) the Magenta Board determines in good faith, based on the advice of its outside legal counsel, that the failure to withhold, amend,

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withdraw or modify such recommendation would reasonably be expected to be inconsistent with its fiduciary duties under applicable Law, (ii) Magenta has, and has caused its financial advisors and outside legal counsel to, during the Magenta Notice Period (as defined below), negotiated with the Company in good faith to make such adjustments to the terms and conditions of this Agreement so that such Acquisition Proposal ceases to constitute a Superior Offer, and (iii) if after the Company shall have delivered to the Company a written offer to alter the terms or conditions of this Agreement during the Magenta Notice Period, the Magenta Board shall have determined in good faith, based on the advice of its outside legal counsel, that the failure to withhold, amend, withdraw or modify the Magenta Board Recommendation would reasonably be expected to be inconsistent with its fiduciary duties under applicable Law (after taking into account such alterations of the terms and conditions of this Agreement); provided that (x) the Company receives written notice from Magenta confirming that the Magenta Board has determined to change its recommendation at least four (4) Business Days in advance of the Magenta Board Adverse Recommendation Change (the “Magenta Notice Period”), which notice shall include a description in reasonable detail of the reasons for such Magenta Board Adverse Recommendation Change, and written copies of any relevant proposed transaction agreements with any party making a potential Superior Offer, (y) during any Magenta Notice Period, the Company shall be entitled to deliver to Magenta one or more counterproposals to such Acquisition Proposal and Magenta will, and cause its Representatives to, negotiate with the Company in good faith (to the extent the Company desires to negotiate) to make such adjustments in the terms and conditions of this Agreement so that the applicable Acquisition Proposal ceases to constitute a Superior Offer and (z) in the event of any material amendment to any Superior Offer (including any revision in the amount, form or mix of consideration the Magenta’s stockholders would receive as a result of such potential Superior Offer), Magenta shall be required to provide the Company with notice of such material amendment and the Magenta Notice Period shall be extended, if applicable, to ensure that at least three (3) Business Days remain in the Magenta Notice Period following such notification during which the parties shall comply again with the requirements of this Section 6.3(c) and the Magenta Board shall not make a Magenta Board Adverse Recommendation Change prior to the end of such Magenta Notice Period as so extended (it being understood that there may be multiple extensions).

(d) Magenta’s obligation to call, give notice of and hold the Magenta Stockholder Meeting in accordance with Section 6.3(a) shall not be limited or otherwise affected by the commencement, disclosure, announcement or submission of any Superior Offer or Acquisition Proposal, or by any Magenta Board Adverse Recommendation Change.

(e) Nothing contained in this Agreement shall prohibit Magenta or the Magenta Board from complying with Rules 14d-9 and 14e-2(a) promulgated under the Exchange Act; provided, however, that any disclosure made by Magenta or the Magenta Board pursuant to Rules 14d-9 and 14e-2(a) shall be limited to a statement that Magenta is unable to take a position with respect to the bidder’s tender offer unless the Magenta Board determines in good faith, after consultation with its outside legal counsel, that such statement would reasonably be expected to be inconsistent with its fiduciary duties under applicable Law.

6.4 Efforts; Regulatory Approvals.

(a) The Parties shall use reasonable best efforts to consummate the Contemplated Transactions. Without limiting the generality of the foregoing, each Party: (i) shall make all filings and other submissions (if any) and give all notices (if any) required to be made and given by such Party in connection with the Contemplated Transactions, (ii) shall use commercially reasonable efforts to obtain each Consent (if any) reasonably required to be obtained (pursuant to any applicable Law or Contract, or otherwise) by such Party in connection with the Contemplated Transactions or for such Contract to remain in full force and effect, (iii) shall use commercially reasonable efforts to lift any injunction prohibiting, or any other legal bar to, the Contemplated Transactions and (iv) shall use commercially reasonable efforts to satisfy the conditions precedent to the consummation of this Agreement.

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(b) Notwithstanding the generality of the foregoing, each Party shall use commercially reasonable efforts to file or otherwise submit, as soon as practicable after the date of this Agreement, all applications, notices, reports and other documents reasonably required to be filed by such Party with or otherwise submitted by such Party to any Governmental Authority with respect to the Contemplated Transactions, and to submit promptly any additional information requested by any such Governmental Authority. Without limiting the generality of the foregoing, the Parties shall prepare and file, if required, (a) the notification and report forms required to be filed under the Hart–Scott–Rodino Antitrust Improvements Act of 1976 and (b) any notification or other document required to be filed in connection with the Merger under any applicable foreign Law relating to antitrust or competition matters, no later than ten (10) Business Days after the date the Company and Magenta receive notification (in writing or otherwise) from the Federal Trade Commission, the Department of Justice, any state attorney general, foreign antitrust or competition authority or other Governmental Authority that a filing is required in connection with antitrust or competition matters.

(c) Without limiting the generality of the foregoing, Magenta shall give the Company prompt written notice of any litigation against Magenta and/or its directors relating to this Agreement or the Contemplated Transactions (“Transaction Litigation”) (including by providing copies of all pleadings with respect thereto) and keep Company reasonably informed with respect to the status thereof. Magenta will (i) give the Company the opportunity to participate in, but not control, the defense, settlement or prosecution of any Transaction Litigation (to the extent that the attorney-client privilege is not undermined or otherwise adversely affected; provided that Magenta and the Company will use commercially reasonable efforts to find alternative solutions to not undermine or adversely effect the privilege such as entering into common interest agreements, joint defense agreements or similar agreements), (ii) consult with the Company with respect to the defense, settlement and prosecution of any Transaction Litigation and (iii) consider in good faith the Company’s advice with respect to such Transaction Litigation. Magenta will obtain the prior written consent of the Company (such consent not to be unreasonably withheld, conditioned or delayed) prior to settling or satisfying any such claim.

6.5 Company Options; Company Warrants.

(a) At the Effective Time, Magenta shall assume each Company Equity Incentive Plan and each Company Option, whether vested or unvested, that is outstanding immediately prior to the Effective Time shall, at the Effective Time, cease to represent a right to acquire shares of Company Common Stock and shall be converted, at the Effective Time, into an option to purchase shares of Magenta Common Stock (an “Assumed Option”), on the same terms and conditions (including any vesting provisions and any provisions providing for accelerated vesting upon certain events) as were applicable under such Company Option as of immediately prior to the Effective Time, except for administrative or ministerial changes as determined by the Company Board (or, following the Effective Time, the Magenta Board or compensation committee). The number of shares of Magenta Common Stock subject to each such Assumed Option shall be equal to (i) the number of shares of Company Common Stock subject to the respective Company Option immediately prior to the Effective Time multiplied by (ii) the Exchange Ratio, rounded down, if necessary, to the nearest whole share of Magenta Common Stock, and such Assumed Option shall have an exercise price per share (rounded up to the nearest whole cent) equal to (A) the exercise price per share of the Company Common Stock otherwise purchasable pursuant to the respective Company Option immediately prior to the Effective Time divided by (B) the Exchange Ratio; provided, that in the case of any Company Option to which Section 421 of the Code applies as of immediately prior to the Effective Time (taking into account the effect of any accelerated vesting thereof, if applicable) by reason of its qualification under Section 422 of the Code, the exercise price, the number

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of shares of Magenta Common Stock subject to such option and the terms and conditions of exercise of such option shall be determined in a manner consistent with the requirements of Section 424(a) of the Code; provided further, that in the case of any Assumed Option to which Section 409A of the Code applies as of the Effective Time, the exercise price, the number of shares of Magenta Common Stock subject to such option and the terms and conditions of exercise of such option shall be determined in a manner consistent with the requirements of Section 409A of the Code in order to avoid the imposition of any additional taxes thereunder. The Company Board shall, prior to the Effective Time, take all actions necessary to effect the foregoing.

(b) At the Effective Time, each Company Warrant (including any pre-funded Company Warrant issued pursuant to any Company Pre-Closing Financing), whether vested or unvested, that is outstanding immediately prior to the Effective Time shall, at the Effective Time, cease to represent a right to acquire shares of Company Capital Stock and shall be converted, at the Effective Time, into a warrant to purchase shares of Magenta Common Stock (an “Assumed Warrant”), on the same terms and conditions (including any vesting provisions and any provisions providing for accelerated vesting upon certain events) as were applicable under such Assumed Warrant as of immediately prior to the Effective Time. The number of shares of Magenta Common Stock subject to each such Assumed Warrant shall be equal to (i) the number of shares of the Company Common Stock subject to each Assumed Warrant immediately prior to the Effective Time multiplied by (ii) the Exchange Ratio, rounded down, if necessary, to the nearest whole share of Magenta Common Stock, and such Assumed Warrant shall have an exercise price per share (rounded up to the nearest whole cent) equal to (A) the exercise price per share of the Company Common Stock otherwise purchasable pursuant to such Assumed Warrant immediately prior to the Effective Time divided by (B) the Exchange Ratio.

6.6 Employee Benefits.

(a) Magenta shall comply with the terms of any employment, severance, retention, change of control, or similar agreement specified on Section 4.17(d) or contemplated by Section 5.1(b) of the Magenta Disclosure Schedule, subject to the provisions of such agreements.

(b) From and after the Effective Time, with respect to each benefit plan maintained by Magenta or the Surviving Corporation that is an “employee welfare benefit plan” as defined in Section 3(1) of ERISA (each, a “Post-Closing Welfare Plan”) in which any current or former employee of Magenta is or becomes eligible to participate (including under COBRA), Magenta and the Surviving Corporation shall use commercially reasonable efforts to cause each such Post-Closing Welfare Plan to (i) waive all limitations as to pre-existing conditions, waiting periods, required physical examinations and exclusions with respect to participation and coverage requirements applicable under such Post-Closing Welfare Plan for such current or former Magenta employee and his or her eligible dependents to the same extent that such pre-existing conditions, waiting periods, required physical examinations and exclusions would not have applied or would have been waived under the corresponding Magenta Employee Plan in which such current or former Magenta employee was a participant immediately prior to his or her commencement of participation in such Post-Closing Welfare Plan, and (ii) provide each such current or former Magenta employee and his or her eligible dependents with credit for any co-payments and deductibles paid in the plan year that includes the Effective Time, and prior to the date that, such current or former Magenta employee commences participation in such Post-Closing Welfare Plan in satisfying any applicable co-payment or deductible requirements under such Post-Closing Welfare Plan for the applicable plan year, to the extent that such expenses were recognized for such purposes under the comparable Magenta Employee Plan.

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6.7 Magenta Equity Awards.

(a) Magenta Options. Prior to the Closing, the Magenta Board shall have adopted appropriate resolutions and taken all other actions necessary and appropriate to provide that (i) the vesting and exercisability of each unexpired, unexercised and unvested Magenta Option shall be accelerated in full effective as of immediately prior to the Effective Time, and (ii) each Magenta Option that has an exercise price per share equal to or less than $2.00, is unexpired and unexercised as of the Effective Time, and is held by a current employee, director or consultant of Magenta as of the Effective Time, shall remain outstanding and exercisable until the three year anniversary of the Closing Date (or, if earlier, the original expiration date of such Magenta Option). Except as otherwise provided by this Section 6.7(a), each Magenta Option shall continue to be subject to the same terms and conditions after the Effective Time as were applicable under such Magenta Option as of immediately prior to the Effective Time.

(b) Magenta Restricted Stock Units. Prior to the Closing, the Magenta Board shall have adopted appropriate resolutions and taken all other actions necessary and appropriate to provide that (i) the vesting of each outstanding and unvested Magenta Restricted Stock Unit that vests solely on the basis of time shall be accelerated in full effective as of immediately prior to the Effective Time, contingent on the occurrence of the Closing and (ii) for each outstanding and unsettled Magenta Restricted Stock Unit that vests solely on the basis of time (including any Magenta Restricted Stock Units accelerated under Section 6.7(b)(i) above) the holder thereof shall receive, immediately prior to the Effective Time a number of shares of Magenta Common Stock equal to the number of vested and unsettled shares underlying such Magenta Restricted Stock Units. Notwithstanding anything herein to the contrary, the tax withholding obligations for each holder receiving shares of Magenta Common Stock in accordance with the preceding sentence shall be satisfied by Magenta withholding from issuance that number of shares of Magenta Common Stock calculated by multiplying the legally-required withholding rate for such holder in connection with such issuance by the number of shares of Magenta Common Stock to be issued in accordance with the preceding sentence, and rounding up to the nearest whole share and remitting such withholding in cash to the appropriate taxing authorities. For the avoidance of doubt, any Magenta Restricted Stock Unit that vests in whole or in part based on the achievement of performance goals shall not be impacted by this Section 6.7(b) and shall remain in effect in accordance with their terms.

6.8 Indemnification of Officers and Directors.

(a) From the Effective Time through the sixth anniversary of the date on which the Effective Time occurs, each of Magenta and the Surviving Corporation shall indemnify and hold harmless each person who is now, or has been at any time prior to the date hereof, or who becomes prior to the Effective Time, a director or officer of Magenta or the Company, respectively (the “D&O Indemnified Parties”), against all claims, losses, liabilities, damages, judgments, fines and reasonable fees, costs and expenses, including attorneys’ fees and disbursements (collectively, “Costs”), incurred in connection with any claim, action, suit, proceeding or investigation, whether civil, criminal, administrative or investigative, arising out of or pertaining to the fact that the D&O Indemnified Party is or was a director or officer of Magenta or of the Company, whether asserted or claimed prior to, at or after the Effective Time, in each case, to the fullest extent permitted under the DGCL. Each D&O Indemnified Party will be entitled to advancement of expenses incurred in the defense of any such claim, action, suit, proceeding or investigation from each of Magenta and the Surviving Corporation, jointly and severally, upon receipt by Magenta or the Surviving Corporation from the D&O Indemnified Party of a request therefor; provided that any such person to whom expenses are advanced provides an undertaking to Magenta, to the extent then required by the DGCL, to repay such advances if it is ultimately determined that such person is not entitled to indemnification. Without otherwise limiting the D&O Indemnified Parties’ rights with regards to counsel, following the Effective Time, the D&O Indemnified Parties shall be entitled to continue to retain Goodwin Procter LLP or such other counsel selected by the D&O Indemnified Parties.

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(b) The provisions of the certificate of incorporation and bylaws of Magenta with respect to indemnification, advancement of expenses and exculpation of present and former directors and officers of Magenta that are presently set forth in the certificate of incorporation and bylaws of Magenta shall not be amended, modified or repealed for a period of six (6) years from the Effective Time in a manner that would adversely affect the rights thereunder of individuals who, at or prior to the Effective Time, were officers or directors of Magenta, unless such modification is required by applicable Law. The certificate of incorporation and bylaws of the Surviving Corporation shall contain, and Magenta shall cause the certificate of incorporation and bylaws of the Surviving Corporation to so contain, provisions no less favorable with respect to indemnification, advancement of expenses and exculpation of present and former directors and officers as those presently set forth in the certificate of incorporation and bylaws of Magenta.

(c) From and after the Effective Time, (i) the Surviving Corporation shall fulfill and honor in all respects the obligations of the Company to its D&O Indemnified Parties as of immediately prior to the Closing pursuant to any indemnification provisions under the Company’s Organizational Documents and pursuant to any indemnification agreements between the Company and such D&O Indemnified Parties, with respect to claims arising out of matters occurring at or prior to the Effective Time and (ii) Magenta shall fulfill and honor in all respects the obligations of Magenta to its D&O Indemnified Parties as of immediately prior to the Closing pursuant to any indemnification provisions under Magenta’s Organizational Documents and pursuant to any indemnification agreements between Magenta and such D&O Indemnified Parties, with respect to claims arising out of matters occurring at or prior to the Effective Time.

(d) From and after the Effective Time, Magenta shall maintain directors’ and officers’ liability insurance policies, with an effective date as of the Closing Date, on commercially reasonable terms and conditions and with coverage limits customary for U.S. public companies similarly situated to Magenta. In addition, Magenta shall purchase, prior to the Effective Time, a six (6) year prepaid “D&O tail policy” for the non-cancelable extension of the directors’ and officers’ liability coverage of Magenta’s existing directors’ and officers’ insurance policies for a claims reporting or discovery period of at least six (6) years from and after the Effective Time with respect to any claim related to any period of time at or prior to the Effective Time with terms, conditions, retentions and limits of liability that are no less favorable than the coverage provided under Magenta’s existing policies as of the date of this Agreement, except that Magenta will not commit or spend on such “D&O Tail policy” annual premiums in excess of 250% of the annual premiums paid by Magenta in its last full fiscal year prior to the date hereof for Magenta’s current policies of directors’ and officers’ liability insurance and fiduciary liability insurance, and if such premiums for such “D&O tail policy” would exceed 250% of such annual premium, then Magenta shall purchase policies that provide the maximum coverage available at an annual premium equal to 250% of such annual premium. The Company shall in good faith cooperate with Magenta prior to the Effective Time with respect to the procurement of such “D&O tail policy.”

(e) From and after the Effective Time, Magenta shall pay all expenses, including reasonable attorneys’ fees, that are incurred by the persons referred to in this Section 6.8 in connection with their enforcement of the rights provided to such persons in this Section 6.8.

(f) The provisions of this Section 6.8 are intended to be in addition to the rights otherwise available to the current and former officers and directors of Magenta and the Company by Law, charter, statute, bylaw or agreement, and shall operate for the benefit of, and shall be enforceable by, each of the D&O Indemnified Parties, their heirs and their Representatives.

(g) In the event Magenta or the Surviving Corporation or any of their respective successors or assigns (i) consolidates with or merges into any other Person and shall not be the continuing or surviving corporation or entity of such consolidation or merger or (ii) transfers all or

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substantially all of its properties and assets to any Person, then, and in each such case, proper provision shall be made so that the successors and assigns of Magenta or the Surviving Corporation, as the case may be, shall succeed to the obligations set forth in this Section 6.8. Magenta shall cause the Surviving Corporation to perform all of the obligations of the Surviving Corporation under this Section 6.8.

6.9 Disclosure. The Parties shall use their commercially reasonable efforts to agree to the text of any initial press release and Magenta’s Form 8-K announcing the execution and delivery of this Agreement. Without limiting any Party’s obligations under the Confidentiality Agreement, no Party shall, and no Party shall permit any of its Subsidiaries or any of its Representative to, issue any press release or make any disclosure (to any customers or employees of such Party, to the public or otherwise) regarding the Contemplated Transactions unless: (a) the other Party shall have approved such press release or disclosure in writing, such approval not to be unreasonably conditioned, withheld or delayed; or (b) such Party shall have determined in good faith, upon the advice of outside legal counsel, that such disclosure is required by applicable Law and, to the extent practicable, before such press release or disclosure is issued or made, such Party advises the other Party of, and consults with the other Party regarding, the text of such press release or disclosure; provided, however, that each of the Company and Magenta may make any public statement in response to specific questions by the press, analysts, investors or those attending industry conferences or financial analyst conference calls, so long as any such statements are consistent with previous press releases, public disclosures or public statements made by the Company or Magenta in compliance with this Section 6.9. Notwithstanding the foregoing, a Party need not consult with any other Parties in connection with such portion of any press release, public statement or filing to be issued or made pursuant to Section 6.2(d) or pursuant to Section 6.3(e).

6.10 Listing. At or prior to the Effective Time, Magenta shall use its commercially reasonable efforts to (a) maintain its listing on Nasdaq until the Effective Time and to obtain approval of the listing of the combined corporation on Nasdaq, (b) to the extent required by the rules and regulations of Nasdaq, prepare and submit to Nasdaq a notification form for the listing of the shares of Magenta Common Stock to be issued in connection with the Contemplated Transactions, and to cause such shares to be approved for listing (subject to official notice of issuance); (c) prepare and timely submit to Nasdaq a notification form for the Nasdaq Reverse Split (if required) and to submit a copy of the amendment to Magenta’s certificate of incorporation effecting the Nasdaq Reverse Split, certified by the Secretary of State of the State of Delaware, to Nasdaq on the Closing Date; and (d) to the extent required by Nasdaq Marketplace Rule 5110, assist the Company in preparing and filing an initial listing application for the Magenta Common Stock on Nasdaq (the “Nasdaq Listing Application”) and to cause such Nasdaq Listing Application to be conditionally approved prior to the Effective Time. Each Party will reasonably promptly inform the other Party of all verbal or written communications between Nasdaq and such Party or its representatives. The Parties will use commercially reasonable efforts to coordinate with respect to compliance with Nasdaq rules and regulations. The Party not filing the Nasdaq Listing Application will cooperate with the other Party as reasonably requested by such filing Party with respect to the Nasdaq Listing Application and promptly furnish to such filing Party all information concerning itself and its members that may be required or reasonably requested in connection with any action contemplated by this Section 6.10. All Nasdaq fees associated with any action contemplated by this Section 6.10 (the “Nasdaq Fees”) shall be shared equally by the Company and Magenta.

6.11 Tax Matters.

(a) The Parties shall use reasonable best efforts (and each shall cause its Affiliates) to cause the Merger to qualify for the Intended Tax Treatment. No Party shall take any actions, or fail to take any action, which action or failure to act would reasonably be expected to prevent or impede the Intended Tax Treatment. The Parties shall report the Contemplated Transactions for all applicable Tax purposes in a manner that is consistent with the Intended Tax Treatment. No Party shall take any position

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that is inconsistent with the Intended Tax Treatment during the course of any audit, litigation or other proceeding with respect to Taxes, in each case, unless otherwise required by a determination within the meaning of Section 1313(a) of the Code. The Parties shall comply with the recordkeeping and information reporting requirements imposed on them, including, but not limited to, those set forth in Treasury Regulation Section 1.368-3.

(b) Magenta shall promptly notify the Company if, at any time before the Effective Time, Magenta becomes aware of any fact or circumstance that would reasonably be expected to prevent, cause a failure of, or impede the Intended Tax Treatment. The Company shall promptly notify Magenta if, at any time before the Effective Time, the Company becomes aware of any fact or circumstance that would reasonably be expected to prevent, cause a failure of, or impede the Intended Tax Treatment.

(c) If the SEC requires that an opinion with respect to the Intended Tax Treatment be prepared and submitted in connection with the Registration Statement and Proxy Statement, (i) the Company shall cause Gibson, Dunn and Crutcher LLP (or such other nationally recognized law or accounting firm reasonably satisfactory to the Company) to furnish such opinion (as so required and subject to customary assumptions and limitations) and (ii) Magenta and the Company shall each deliver to Gibson, Dunn and Crutcher LLP (or such other nationally recognized law or accounting firm reasonably satisfactory to the Company) a Tax certificate, dated as of the date the Registration Statement and Proxy Statement shall have been declared effective by the SEC and signed by an officer of Magenta or the Company, as applicable, containing customary representations and covenants reasonably acceptable to the Company and Magenta, as applicable, in each case, as reasonably necessary and appropriate to enable such advisors to render such opinion (the “Tax Certificates”). Each of Magenta and the Company shall use its commercially reasonable efforts not to take or cause to be taken any action that would cause to be untrue (or fail to take or cause not to be taken any action which would cause to be untrue) any of the Tax certifications, covenants or representations included in the Tax Certificates.

(d) Magenta and the Company shall reasonably cooperate in the preparation, execution and filing of all Tax Returns, questionnaires, applications or other documents regarding any real property transfer, sales, use, transfer, value added, stock transfer and stamp taxes, and transfer, recording, registration and other fees and similar Taxes which become payable in connection with the Merger that are required or permitted to be filed on or before the Effective Time. Each of Magenta and the Company shall pay, without deduction from any consideration or other amounts payable or otherwise deliverable pursuant to this Agreement and without reimbursement from the other party, any such Taxes or fees imposed on it by any Governmental Authority, which becomes payable in connection with the Merger.

6.12 Legends. Magenta shall be entitled to place appropriate legends on the book entries and/or certificates evidencing any shares of Magenta Common Stock to be received in the Merger by equityholders of the Company who may be considered “affiliates” of Magenta for purposes of Rules 144 and 145 under the Securities Act reflecting the restrictions set forth in Rules 144 and 145 and to issue appropriate stop transfer instructions to the transfer agent for Magenta Common Stock.

6.13 Officers and Directors. Until successors are duly elected or appointed and qualified in accordance with applicable Law, the Parties shall use commercially reasonable efforts and take all necessary action so that the Persons listed on Section 6.13 of the Magenta Disclosure Schedule are elected or appointed, as applicable, to the positions of officers or directors of Magenta and the Surviving Corporation, as set forth therein, to serve in such positions effective as of the Effective Time. If any Person listed on Section 6.13 of the Magenta Disclosure Schedule is unable or unwilling to serve as officer or director of Magenta or the Surviving Corporation, as set forth therein, the Party appointing such Person (as set forth on Section 6.13 of the Magenta Disclosure Schedule) shall designate a successor. The Parties shall use reasonable best efforts to have each of the Persons that will serve as directors and officers of the Magenta following the Closing to execute and deliver a Lock-Up Agreement prior to Closing.

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6.14 Termination of Certain Agreements and Rights. Except as set forth on Section 6.14 of the Magenta Disclosure Schedule, each of Magenta and the Company shall cause any stockholder agreements, voting agreements, registration rights agreements, co-sale agreements and any other similar Contracts between either Magenta or the Company and any holders of Magenta Common Stock or Company Capital Stock, respectively, including any such Contract granting any Person investor rights, rights of first refusal, registration rights or director registration rights, to be terminated immediately prior to the Effective Time, without any liability being imposed on the part of Magenta or the Surviving Corporation.

6.15 Section 16 Matters. Prior to the Effective Time, Magenta shall take all such steps as may be required to cause any acquisitions of Magenta Common Stock and any options to purchase Magenta Common Stock in connection with the Contemplated Transactions, by each individual who is reasonably expected to become subject to the reporting requirements of Section 16(a) of the Exchange Act with respect to Magenta, to be exempt under Rule 16b-3 promulgated under the Exchange Act.

6.16 Allocation Certificate. The Company will prepare and deliver to Magenta prior to the Closing a certificate signed by the Company’s Chief Executive Officer in a form reasonably acceptable to Magenta setting forth (as of immediately prior to the Effective Time) (a) each holder of Company Capital Stock, (b) such holder’s name and address, (c) the number or percentage and type of Company Capital Stock held as of the Closing Date for each such holder and (d) the number of shares of Magenta Common Stock to be issued to such holder pursuant to this Agreement in respect of the Company Capital Stock held by such holder as of immediately prior to the Effective Time (the “Allocation Certificate”).

6.17 Wind-Down Activities. Following the Closing, Magenta shall use its commercially reasonable efforts to continue the wind-down activities of Magenta associated with the termination of its research and development activities set forth on Section 6.17 of the Magenta Disclosure Schedule.

6.18 Magenta SEC Documents. From the date of this Agreement to the Effective Time, Magenta shall timely file with the SEC all registration statements, proxy statements, Certifications, reports, schedules, exhibits, forms and other documents required to be filed by Magenta with the SEC required to be filed by it under the Exchange Act or the Securities Act (“SEC Documents”). As of its filing date, or if amended after the date of this Agreement, as of the date of the last such amendment, each SEC Document filed by Magenta with the SEC (a) shall comply in all material respects with the applicable requirements of the Exchange Act and the Securities Act, and (b) shall not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements made therein, in light of the circumstances under which they were made, not misleading.

6.19 Obligations of Merger Sub. Magenta will take all action necessary to cause Merger Sub to perform their obligations under this Agreement and to consummate the Merger on the terms and conditions set forth in this Agreement.

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Section 7. Conditions Precedent to Obligations of Each Party. The obligations of each Party to effect the Merger and otherwise consummate the Contemplated Transactions to be consummated at the Closing are subject to the satisfaction or, to the extent permitted by applicable law, the written waiver by each of the Parties, at or prior to the Closing, of each of the following conditions:

7.1 Effectiveness of Registration Statement. The Registration Statement shall have become effective in accordance with the provisions of the Securities Act, and shall not be subject to any stop order or proceeding (or threatened proceeding by the SEC) seeking a stop order with respect to the Registration Statement that has not been withdrawn. Any material state securities laws applicable to the issuance of the shares of Magenta Common Stock in connection with the Contemplated Transactions shall have been complied with and no stop order (or similar order) shall have been issued or threatened in writing in respect of such shares of Magenta Common Stock by any applicable state securities commissioner or court of competent jurisdiction.

7.2 No Restraints. No temporary restraining order, preliminary or permanent injunction or other Order preventing the consummation of the Contemplated Transactions shall have been issued by any court of competent jurisdiction or other Governmental Authority of competent jurisdiction and remain in effect and there shall not be any Law which has the effect of making the consummation of the Contemplated Transactions illegal.

7.3 Stockholder Approval. (a) Magenta shall have obtained the Required Magenta Stockholder Vote and (b) the Company shall have obtained the Required Company Stockholder Vote.

7.4 Listing. The approval of the listing of the additional shares of Magenta Common Stock on Nasdaq shall have been obtained and the shares of Magenta Common Stock to be issued in the Contemplated Transactions pursuant to this Agreement shall have been approved for listing (subject to official notice of issuance) on Nasdaq.

7.5 Lock-Up Agreements. The Lock-Up Agreements shall be in full force and effect.

Section 8. Additional Conditions Precedent to Obligations of Magenta and Merger Sub. The obligations of Magenta and Merger Sub to effect the Merger and otherwise consummate the transactions to be consummated at the Closing are subject to the satisfaction or the written waiver by Magenta, at or prior to the Closing, of each of the following conditions:

8.1 Accuracy of Representations. The Company Fundamental Representations shall have been true and correct in all material respects as of the date of this Agreement and shall be true and correct on and as of the Closing Date with the same force and effect as if made on and as of such date (except to the extent such representations and warranties are specifically made as of a particular date, in which case such representations and warranties shall be true and correct as of such date). The Company Capitalization Representations shall have been true and correct in all respects as of the date of this Agreement and shall be true and correct on and as of the Closing Date with the same force and effect as if made on and as of such date, except, in each case, (x) for such inaccuracies which are de minimis, individually or in the aggregate, or (y) for those representations and warranties which address matters only as of a particular date (which representations and warranties shall have been true and correct, subject to the qualifications as set forth in the preceding clause (x), as of such particular date). The representations and warranties of the Company contained in this Agreement (other than the Company Fundamental Representations and the Company Capitalization Representations) shall have been true and correct as of the date of this Agreement and shall be true and correct on and as of the Closing Date with the same force and effect as if made on the Closing Date except (a) in each case, or in the aggregate, where the failure to be so true and correct would not reasonably be expected to have a Company Material Adverse Effect (without giving effect to any references therein to any Company Material Adverse Effect or other materiality qualifications) or (b) for those representations and warranties which address matters only as of a particular date (which representations shall have been true and correct, subject to the qualifications as set forth in the preceding clause (a), as of such particular date) (it being understood that, for purposes of determining the accuracy of such representations and warranties, any update of or modification to the Company Disclosure Schedule made or purported to have been made after the date of this Agreement shall be disregarded).

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8.2 Performance of Covenants. The Company shall have performed or complied with in all material respects all agreements and covenants required to be performed or complied with by it under this Agreement at or prior to the Effective Time.

8.3 Documents. Magenta shall have received the following documents, each of which shall be in full force and effect:

(a) a certificate executed by the Chief Executive Officer or Chief Financial Officer of the Company certifying (i) that the conditions set forth in Sections 8.1, 8.2, 8.4, 8.5 and 8.6 have been duly satisfied and (ii) that the information (other than emails and addresses) set forth in the Allocation Certificate delivered by the company in accordance with Section 6.16 is true and accurate in all respects as of the Closing Date;

(b) a certificate pursuant to Treasury Regulations Sections 1.1445-2(c) and 1.897-2(h), together with a form of notice to the IRS in accordance with the requirements of Treasury Regulations Section 1.897-2(h), in each case, in form and substance reasonably acceptable to Magenta;

(c) the Company Valuation Schedule; and

(d) the Allocation Certificate.

8.4 No Company Material Adverse Effect. Since the date of this Agreement, there shall not have occurred any Company Material Adverse Effect.

8.5 Company Stockholder Written Consent. The Company Stockholder Written Consent executed by the stockholders of the Company shall be in full force and effect.

8.6 Company Pre-Closing Financing. The Subscription Agreement shall be in full force and effect and cash proceeds of not less than the Concurrent Investment Amount shall have been received by the Company, or will be received by the Company substantially simultaneously with the Closing, in connection with the consummation of the transactions contemplated by the Subscription Agreement.

Section 9. Additional Conditions Precedent to Obligation of the Company. The obligations of the Company to effect the Merger and otherwise consummate the transactions to be consummated at the Closing are subject to the satisfaction or the written waiver by the Company, at or prior to the Closing, of each of the following conditions:

9.1 Accuracy of Representations. Each of the Magenta Fundamental Representations shall have been true and correct in all material respects as of the date of this Agreement and shall be true and correct on and as of the Closing Date with the same force and effect as if made on and as of such date (except to the extent such representations and warranties are specifically made as of a particular date, in which case such representations and warranties shall be true and correct as of such date). The Magenta Capitalization Representations shall have been true and correct in all respects as of the date of this Agreement and shall be true and correct on and as of the Closing Date with the same force and effect as if made on and as of such date, except, in each case, (x) for such inaccuracies which are de minimis, individually or in the aggregate, (y) for those representations and warranties which address matters only as of a particular date (which representations and warranties shall have been true and correct, subject to the

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qualifications as set forth in the preceding clause (x), as of such particular date) or (z) variances arising solely due to the transactions contemplated under the Subscription Agreement. The representations and warranties of Magenta and Merger Sub contained in this Agreement (other than the Magenta Fundamental Representations and the Magenta Capitalization Representations) shall have been true and correct as of the date of this Agreement and shall be true and correct on and as of the Closing Date with the same force and effect as if made on the Closing Date except (a) in each case, or in the aggregate, where the failure to be true and correct would not reasonably be expected to have a Magenta Material Adverse Effect (without giving effect to any references therein to any Magenta Material Adverse Effect or other materiality qualifications) or (b) for those representations and warranties which address matters only as of a particular date (which representations shall have been true and correct, subject to the qualifications as set forth in the preceding clause (a), as of such particular date) (it being understood that, for purposes of determining the accuracy of such representations and warranties, any update of or modification to the Magenta Disclosure Schedule made or purported to have been made after the date of this Agreement shall be disregarded).

9.2 Performance of Covenants. Magenta and Merger Sub shall have performed or complied with in all material respects all of their agreements and covenants required to be performed or complied with by each of them under this Agreement at or prior to the Effective Time.

9.3 Documents. The Company shall have received the following documents, each of which shall be in full force and effect:

(a) a certificate executed by an executive officer of Magenta certifying that the conditions set forth in Sections 9.1, 9.2 and 9.4 have been duly satisfied;

(b) written resignations in forms satisfactory to the Company, dated as of the Closing Date and effective as of the Closing executed by the officers and directors of Magenta who are not to continue as officers or directors of Magenta pursuant to Section 6.13 hereof; and

(c) the Magenta Net Cash Schedule.

9.4 No Magenta Material Adverse Effect. Since the date of this Agreement, there shall not have occurred any Magenta Material Adverse Effect.

Section 10. Termination.

10.1 Termination. This Agreement may be terminated prior to the Effective Time (whether before or after adoption of this Agreement by the Company’s stockholders and whether before or after approval of the Magenta Stockholder Matters by Magenta’s stockholders, unless otherwise specified below):

(a) by mutual written consent of Magenta and the Company;

(b) by either Magenta or the Company if the Merger shall not have been consummated by November 2, 2023 (subject to possible extension as provided in this Section 10.1(b), the “End Date”); provided, however, that the right to terminate this Agreement under this Section 10.1(b) shall not be available to the Company or Magenta if such Party’s (or in the case of Magenta, Merger Sub) action or failure to act has been a principal cause of the failure of the Merger to occur on or before the End Date and such action or failure to act constitutes a breach of this Agreement, provided further, however, that, in the event that the SEC has not declared effective under the Securities Act the Registration Statement by the date which is sixty (60) days prior to the End Date, then either the Company or Magenta shall be entitled to extend the End Date for an additional sixty (60) days;

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(c) by either Magenta or the Company if a court of competent jurisdiction or other Governmental Authority shall have issued a final and nonappealable Order, or shall have taken any other action, having the effect of permanently restraining, enjoining or otherwise prohibiting the Contemplated Transactions;

(d) by Magenta if the Required Company Stockholder Vote shall not have been obtained within two (2) Business Days of the Registration Statement becoming effective in accordance with the provisions of the Securities Act; provided, however, that once the Required Company Stockholder Vote has been obtained, Magenta may not terminate this Agreement pursuant to this Section 10.1(d);

(e) by either Magenta or the Company if (i) the Magenta Stockholder Meeting (including any adjournments and postponements thereof) shall have been held and completed and Magenta’s stockholders shall have taken a final vote on the Magenta Stockholder Matters and (ii) the Magenta Stockholder Matters shall not have been approved at the Magenta Stockholder Meeting (or at any adjournment or postponement thereof) by the Required Magenta Stockholder Vote; provided, however, that the right to terminate this Agreement under this Section 10.1(e) shall not be available to Magenta where the failure to obtain the Required Magenta Stockholder Vote shall have been caused by the action or failure to act of Magenta and such action or failure to act constitutes a material breach by Magenta of this Agreement;

(f) by the Company (at any time prior to the approval of the Magenta Stockholder Matters by the Required Magenta Stockholder Vote) if a Magenta Triggering Event shall have occurred;

(g) by Magenta (at any time prior to the adoption of this Agreement and the approval of the Contemplated Transactions by the Required Company Stockholder Vote) if a Company Triggering Event shall have occurred;

(h) by the Company, upon a breach of any representation, warranty, covenant or agreement set forth in this Agreement by Magenta or Merger Sub or if any representation or warranty of Magenta or Merger Sub shall have become inaccurate, in either case, such that the conditions set forth in Section 9.1 or Section 9.2 would not be satisfied as of the time of such breach or as of the time such representation or warranty shall have become inaccurate; provided, that the Company is not then in material breach of any representation, warranty, covenant or agreement under this Agreement; provided further, that if such inaccuracy in Magenta’s or Merger Sub’s representations and warranties or breach by Magenta or Merger Sub is curable by Magenta or Merger Sub, then this Agreement shall not terminate pursuant to this Section 10.1(h) as a result of such particular breach or inaccuracy until the earlier of (i) the expiration of a thirty-(30) day period commencing upon delivery of written notice from the Company to Magenta or Merger Sub of such breach or inaccuracy and its intention to terminate pursuant to this Section 10.1(h) and (ii) Magenta or Merger Sub (as applicable) ceasing to exercise commercially reasonable efforts to cure such breach following delivery of written notice from the Company to Magenta or Merger Sub of such breach or inaccuracy and its intention to terminate pursuant to this Section 10.1(h) (it being understood that this Agreement shall not terminate pursuant to this Section 10.1(h) as a result of such particular breach or inaccuracy if such breach by Magenta or Merger Sub is cured prior to such termination becoming effective);

(i) by Magenta, upon a breach of any representation, warranty, covenant or agreement set forth in this Agreement by the Company or if any representation or warranty of the Company shall have become inaccurate, in either case, such that the conditions set forth in Section 8.1 or Section 8.2 would not be satisfied as of the time of such breach or as of the time such representation or warranty shall have become inaccurate; provided that Magenta is not then in material breach of any representation, warranty, covenant or agreement under this Agreement; provided, further, that if such inaccuracy in the Company’s representations and warranties or breach by the Company is curable by the Company then this

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Agreement shall not terminate pursuant to this Section 10.1(i) as a result of such particular breach or inaccuracy until the earlier of (i) the expiration of a thirty-(30) day period commencing upon delivery of written notice from Magenta to the Company of such breach or inaccuracy and its intention to terminate pursuant to this Section 10.1(i) and (ii) the Company ceasing to exercise commercially reasonable efforts to cure such breach following delivery of written notice from Magenta to the Company of such breach or inaccuracy and its intention to terminate pursuant to this Section 10.1(i) (it being understood that this Agreement shall not terminate pursuant to this Section 10.1(i) as a result of such particular breach or inaccuracy if such breach by the Company is cured prior to such termination becoming effective); or

(j) by Magenta (at any time prior to the approval of the Magenta Stockholder Matters by the Required Magenta Stockholder Vote) and following compliance with all of the requirements set forth in the proviso to this Section 10.1(j), upon the Magenta Board authorizing Magenta to enter into a Permitted Alternative Agreement; provided, however, that Magenta shall not enter into any Permitted Alternative Agreement unless: (i) the Company shall have received written notice from Magenta of Magenta’s intention to enter into such Permitted Alternative Agreement at least four (4) Business Days in advance, with such notice describing in reasonable detail the reasons for such intention as well as the material terms and conditions of such Permitted Alternative Agreement, including the identity of the counterparty together with copies of the then current draft of such Permitted Alternative Agreement and any other related principal transaction documents, (ii) Magenta shall have complied in all material respects with its obligations under Section 5.4 and Section 6.3, (iii) the Magenta Board shall have determined in good faith, after consultation with its outside legal counsel, that the failure to enter into such Permitted Alternative Agreement would reasonably be expected to be inconsistent with its fiduciary obligations under applicable Law and (iv) Magenta shall concurrently pay to the Company the Company Termination Fee in accordance with Section 10.3(c).

The Party desiring to terminate this Agreement pursuant to this Section 10.1 (other than pursuant to Section 10.1(a)) shall give a notice of such termination to the other Party specifying the provisions hereof pursuant to which such termination is made and the basis therefor described in reasonable detail.

10.2 Effect of Termination. In the event of the termination of this Agreement as provided in Section 10.1, this Agreement shall be of no further force or effect; provided, however, that (a) this Section 10.2, Section 10.3 and Section 11 (and the related definitions of the defined terms in such section) shall survive the termination of this Agreement and shall remain in full force and effect and (b) the termination of this Agreement and the provisions of Section 10.3 shall not relieve any Party of any liability for fraud or for any willful and material breach of any representation, warranty, covenant, obligation or other provision contained in this Agreement.

10.3 Expenses; Termination Fees.

(a) Except as set forth in this Section 10.3 and Section 6.10 all fees and expenses incurred in connection with this Agreement and the Contemplated Transactions shall be paid by the Party incurring such expenses, whether or not the Merger is consummated.

(b) If (i) this Agreement is terminated by Magenta or the Company pursuant to Section 10.1(e) or by the Company pursuant to Section 10.1(f), (ii) at any time after the date of this Agreement and prior to the Magenta Stockholder Meeting, an Acquisition Proposal with respect to Magenta shall have been publicly announced, disclosed or otherwise communicated to the Magenta Board (and shall not have been withdrawn) and (iii) in the event this Agreement is terminated pursuant to Section 10.1(e), within twelve (12) months after the date of such termination, Magenta enters into a definitive agreement with respect to a Subsequent Transaction or consummates a Subsequent Transaction, then Magenta shall pay to the Company, within ten (10) Business Days after termination (or, if applicable, upon such entry into a definitive agreement or consummation of a Subsequent Transaction), a nonrefundable fee in an amount equal to $13,300,000 (the “Company Termination Fee”).

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(c) If this Agreement is terminated (i) by the Company pursuant to Section 10.1(b) or Section 10.1(e) (when at the time this Agreement is terminated, the Company had the right to terminate this Agreement pursuant to Section 10.1(f)) then Magenta shall pay to the Company within five (5) Business Days of such termination, the Company Termination Fee or (ii) by Magenta pursuant to Section 10.1(j), then Magenta shall pay to the Company, concurrent with such termination, the Company Termination Fee.

(d) If (i) this Agreement is terminated by Magenta pursuant to Section 10.1(d) or Section 10.1(g), (ii) at any time after the date of this Agreement and before obtaining the Required Company Stockholder Vote, an Acquisition Proposal with respect to the Company shall have been publicly announced, disclosed or otherwise communicated to the Company Board (and shall not have been withdrawn) and (iii) in the event this Agreement is terminated pursuant to Section 10.1(d), within twelve (12) months after the date of such termination, the Company enters into a definitive agreement with respect to a Subsequent Transaction or consummates a Subsequent Transaction, then the Company shall pay to Magenta, within ten (10) Business Days after termination (or, if applicable, upon such entry into a definitive agreement or consummation of a Subsequent Transaction), a nonrefundable fee in an amount equal to $13,300,000.

(e) If this Agreement is terminated by the Company pursuant to Section 10.1(h), Magenta shall reimburse the Company for all reasonable out-of-pocket fees and expenses incurred by the Company in connection with this Agreement and the Contemplated Transactions, up to a maximum of $1,500,000, by wire transfer of same-day funds within ten (10) Business Days following the date on which the Company submits to Magenta true and correct copies of reasonable documentation supporting such expenses.

(f) If this Agreement is terminated by Magenta pursuant to Section 10.1(i), the Company shall reimburse Magenta for all reasonable out-of-pocket fees and expenses incurred by Magenta in connection with this Agreement and the Contemplated Transactions, up to a maximum of $1,500,000, by wire transfer of same-day funds within ten (10) Business Days following the date on which Magenta submits to the Company true and correct copies of reasonable documentation supporting such expenses.

(g) If either Party fails to pay when due any amount payable by it under this Section 10.3, then (i) such Party shall reimburse the other Party for reasonable costs and expenses (including reasonable fees and disbursements of counsel) incurred in connection with the collection of such overdue amount and the enforcement by the other Party of its rights under this Section 10.3 and (ii) such Party shall pay to the other Party interest on such overdue amount (for the period commencing as of the date such overdue amount was originally required to be paid and ending on the date such overdue amount is actually paid to the other Party in full) at a rate per annum equal to the “prime rate” (as announced by Bank of America or any successor thereto) in effect on the date such overdue amount was originally required to be paid plus three percent.

(h) The Parties agree that, subject to Section 10.2, the payment of the fees and expenses set forth in this Section 10.3 shall be the sole and exclusive remedy of each Party following a termination of this Agreement under the circumstances described in this Section 10.3, it being understood that in no event shall either Magenta or the Company be required to pay the individual fees or damages payable pursuant to this Section 10.3 on more than one occasion. Subject to Section 10.2, following the payment of the fees and expenses set forth in this Section 10.3 by a Party, (i) such Party shall have no

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further liability to the other Party in connection with or arising out of this Agreement or the termination thereof, any breach of this Agreement by the other Party giving rise to such termination, or the failure of the Contemplated Transactions to be consummated, (ii) no other Party or their respective Affiliates shall be entitled to bring or maintain any other claim, action or proceeding against such Party or seek to obtain any recovery, judgment or damages of any kind against such Party (or any partner, member, stockholder, director, officer, employee, Subsidiary, Affiliate, agent or other Representative of such Party) in connection with or arising out of this Agreement or the termination thereof, any breach by such Party giving rise to such termination or the failure of the Contemplated Transactions to be consummated and (iii) all other Parties and their respective Affiliates shall be precluded from any other remedy against such Party and its Affiliates, at law or in equity or otherwise, in connection with or arising out of this Agreement or the termination thereof, any breach by such Party giving rise to such termination or the failure of the Contemplated Transactions to be consummated. Each of the Parties acknowledges that (x) the agreements contained in this Section 10.3 are an integral part of the Contemplated Transactions, (y) without these agreements, the Parties would not enter into this Agreement and (z) any amount payable pursuant to this Section 10.3 is not a penalty, but rather is liquidated damages in a reasonable amount that will compensate the Parties in the circumstances in which such amount is payable; provided, however, that nothing in this Section 10.3(h) shall limit the rights of the Parties under Section 11.10.

Section 11. Miscellaneous Provisions.

11.1 Non-Survival of Representations and Warranties. The representations and warranties of the Company, Magenta and Merger Sub contained in this Agreement or any certificate or instrument delivered pursuant to this Agreement shall terminate at the Effective Time, and only the covenants that by their terms survive the Effective Time and this Section 11 shall survive the Effective Time.

11.2 Amendment. This Agreement may be amended with the approval of the respective boards of directors of the Company, Merger Sub and Magenta at any time (whether before or after the adoption and approval of this Agreement by the Company’s stockholders or before or after obtaining the Required Magenta Stockholder Vote); provided, however, that after any such approval of this Agreement by a Party’s stockholders, no amendment shall be made which by Law requires further approval of such stockholders without the further approval of such stockholders. This Agreement may not be amended except by an instrument in writing signed on behalf of each of the Company, Merger Sub and Magenta.

11.3 Waiver.

(a) Any provision hereof may be waived by the waiving Party solely on such Party’s own behalf, without the consent of any other Party. No failure on the part of any Party to exercise any power, right, privilege or remedy under this Agreement, and no delay on the part of any Party in exercising any power, right, privilege or remedy under this Agreement, shall operate as a waiver of such power, right, privilege or remedy; and no single or partial exercise of any such power, right, privilege or remedy shall preclude any other or further exercise thereof or of any other power, right, privilege or remedy.

(b) No Party shall be deemed to have waived any claim arising out of this Agreement, or any power, right, privilege or remedy under this Agreement, unless the waiver of such claim, power, right, privilege or remedy is expressly set forth in a written instrument duly executed and delivered on behalf of such Party and any such waiver shall not be applicable or have any effect except in the specific instance in which it is given.

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11.4 Entire Agreement; Counterparts; Exchanges by Electronic Transmission or Facsimile. This Agreement and the other schedules, exhibits, certificates, instruments and agreements referred to in this Agreement constitute the entire agreement and supersede all prior agreements and understandings, both written and oral, among or between any of the Parties with respect to the subject matter hereof and thereof; provided, however, that the Confidentiality Agreement shall not be superseded and shall remain in full force and effect in accordance with its terms. This Agreement may be executed in several counterparts, each of which shall be deemed an original and all of which shall constitute one and the same instrument. The exchange of a fully executed Agreement (in counterparts or otherwise) by all Parties by facsimile or electronic transmission in PDF format shall be sufficient to bind the Parties to the terms and conditions of this Agreement.

11.5 Applicable Law; Jurisdiction. This Agreement shall be governed by, and construed in accordance with, the laws of the State of Delaware, regardless of the laws that might otherwise govern under applicable principles of conflicts of laws. In any action or proceeding between any of the Parties arising out of or relating to this Agreement or any of the Contemplated Transactions, each of the Parties: (a) irrevocably and unconditionally consents and submits to the exclusive jurisdiction and venue of the Court of Chancery of the State of Delaware or, to the extent such court does not have subject matter jurisdiction, the Superior Court of the State of Delaware or the United States District Court for the District of Delaware, (b) agrees that all claims in respect of such action or proceeding shall be heard and determined exclusively in accordance with clause (a) of this Section 11.5, (c) waives any objection to laying venue in any such action or proceeding in such courts, (d) waives any objection that such courts are an inconvenient forum or do not have jurisdiction over any Party, (e) agrees that service of process upon such Party in any such action or proceeding shall be effective if notice is given in accordance with Section 11.7 of this Agreement and (f) irrevocably and unconditionally waives the right to trial by jury.

11.6 Assignability. This Agreement shall be binding upon, and shall be enforceable by and inure solely to the benefit of, the Parties and their respective successors and permitted assigns; provided, however, that neither this Agreement nor any of a Party’s rights or obligations hereunder may be assigned or delegated by such Party without the prior written consent of the other Party, and any attempted assignment or delegation of this Agreement or any of such rights or obligations by such Party without the other Party’s prior written consent shall be void and of no effect.

11.7 Notices. All notices and other communications hereunder shall be in writing and shall be deemed to have been duly delivered and received hereunder (a) one (1) Business Day after being sent for next Business Day delivery, fees prepaid, via a reputable international overnight courier service, (b) upon delivery in the case of delivery by hand or (c) on the date delivered in the place of delivery if sent by email or facsimile (with a written or electronic confirmation of delivery) prior to 6:00 p.m. (New York City time), otherwise on the next succeeding Business Day, in each case to the intended recipient as set forth below:

if to Magenta or Merger Sub:

Magenta Therapeutics, Inc.

300 Technology Square, 8^th Floor

Cambridge, Massachusetts 02139

Attention: Tom Beetham, Chief Legal Officer

Email:

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with a copy to (which shall not constitute notice):

Goodwin Procter LLP

The New York Times Building

620 Eighth Avenue

New York, New York 10018 United States

Attention: William D. Collins; Michael R. Patrone

Email:

if to the Company:

Dianthus Therapeutics, Inc.

7 Times Square

New York, New York 10036

Attention: Ryan Savitz, Chief Financial Officer

Email:

with a copy to (which shall not constitute notice):

Gibson, Dunn & Crutcher LLP

555 Mission Street, Suite 3000

San Francisco, CA 94105

Attention: Ryan Murr, Branden Berns, Chris Trester

Email:

11.8 Cooperation. Each Party agrees to cooperate fully with the other Party and to execute and deliver such further documents, certificates, agreements and instruments and to take such other actions as may be reasonably requested by the other Party to evidence or reflect the Contemplated Transactions and to carry out the intent and purposes of this Agreement.

11.9 Severability. Any term or provision of this Agreement that is invalid or unenforceable in any situation in any jurisdiction shall not affect the validity or enforceability of the remaining terms and provisions of this Agreement or the validity or enforceability of the offending term or provision in any other situation or in any other jurisdiction. If a final judgment of a court of competent jurisdiction declares that any term or provision of this Agreement is invalid or unenforceable, the Parties agree that the court making such determination shall have the power to limit such term or provision, to delete specific words or phrases or to replace such term or provision with a term or provision that is valid and enforceable and that comes closest to expressing the intention of the invalid or unenforceable term or provision, and this Agreement shall be valid and enforceable as so modified. In the event such court does not exercise the power granted to it in the prior sentence, the Parties agree to replace such invalid or unenforceable term or provision with a valid and enforceable term or provision that will achieve, to the extent possible, the economic, business and other purposes of such invalid or unenforceable term or provision.

11.10 Other Remedies; Specific Performance. Except as otherwise provided herein, any and all remedies herein expressly conferred upon a Party will be deemed cumulative with and not exclusive of any other remedy conferred hereby, or by law or equity upon such Party, and the exercise by a Party of any one remedy will not preclude the exercise of any other remedy. The Parties agree that irreparable damage for which monetary damages, even if available, would not be an adequate remedy, would occur in the event that any of the provisions of this Agreement were not performed in accordance with their specific terms (including failing to take such actions as are required of it hereunder to consummate this Agreement) or were otherwise breached. It is accordingly agreed that the Parties shall be entitled to an injunction or injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions

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hereof in the Court of Chancery of the State of Delaware or, to the extent such court does not have subject matter jurisdiction, the Superior Court of the State of Delaware or the United States District Court for the District of Delaware, this being in addition to any other remedy to which they are entitled at law or in equity, and each of the Parties waives any bond, surety or other security that might be required of any other Party with respect thereto. Each of the Parties further agrees that it will not oppose the granting of an injunction, specific performance or other equitable relief on the basis that any other Party has an adequate remedy at law or that any award of specific performance is not an appropriate remedy for any reason at law or in equity.

11.11 No Third-Party Beneficiaries. Nothing in this Agreement, express or implied, is intended to or shall confer upon any Person (other than the Parties and the D&O Indemnified Parties to the extent of their respective rights pursuant to Section 6.8) any right, benefit or remedy of any nature whatsoever under or by reason of this Agreement.

[Remainder of page intentionally left blank]

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IN WITNESS WHEREOF, the Parties have caused this Agreement to be executed as of the date first above written.

[Signature Page to Agreement and Plan of Merger]

IN WITNESS WHEREOF, the Parties have caused this Agreement to be executed as of the date first above written.

[Signature Page to Agreement and Plan of Merger]

Exhibit A-1

FORM OF MAGENTA STOCKHOLDER SUPPORT AGREEMENT

This Support Agreement (this “Agreement”) is made and entered into as of May 2, 2023, by and among Dianthus Therapeutics, Inc., a Delaware corporation (the “Company”), Magenta Therapeutics, Inc., a Delaware corporation (“Magenta”), and the undersigned stockholder (the “Stockholder”) of Magenta. Capitalized terms used herein but not otherwise defined shall have the respective meanings ascribed to such terms in the Merger Agreement (as defined below).

RECITALS

WHEREAS, concurrently with the execution and delivery hereof, Magenta, the Company and Dio Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Magenta (the “Merger Sub”), have entered into an Agreement and Plan of Merger (as such agreement may be amended or supplemented from time to time pursuant to the terms thereof, the “Merger Agreement”), pursuant to which Merger Sub will merge with and into the Company, with the Company surviving the merger as the surviving corporation and a wholly owned subsidiary of Magenta (the “Merger”) upon the terms and subject to the conditions set forth in the Merger Agreement.

WHEREAS, as of the date hereof, the Stockholder is the beneficial owner (as defined in Rule 13d-1 under the Exchange Act) of such number of shares of Magenta Common Stock as indicated in Appendix A.

WHEREAS, as an inducement to the willingness of the Company to enter into the Merger Agreement, the Company has required that Stockholder enter into this Agreement.

NOW, THEREFORE, intending to be legally bound, the parties hereby agree as follows:

1. Certain Definitions. Capitalized terms used but not otherwise defined herein shall have the meanings ascribed thereto in the Merger Agreement. For all purposes of this Agreement, the following terms shall have the following respective meanings:

(a) “Constructive Sale” means, with respect to any security, a short sale with respect to such security, entering into or acquiring a derivative contract with respect to such security, entering into or acquiring a futures or forward contract to deliver such security or entering into any other hedging or other derivative transaction that has the effect of either directly or indirectly materially changing the economic benefits or risks of ownership of such security.

(b) “Magenta Stockholder Matters” means the approval of the Merger Agreement and the Contemplated Transactions, and, if deemed necessary by Magenta, an amendment to Magenta’s certificate of incorporation to effect the Nasdaq Reverse Split.

(c) “Shares” means (i) all shares of Magenta Common Stock owned, beneficially or of record, by the Stockholder as of the date hereof, and (ii) all additional shares of Magenta Common Stock acquired by the Stockholder, beneficially or of record, during the period commencing with the execution and delivery of this Agreement and expiring on the Closing Date.

Exhibit A-1 – Page 1

(d) “Transfer” or “Transferred” means, with respect to any security, the direct or indirect assignment, sale, transfer, tender, exchange, pledge or hypothecation, or the grant, creation or suffrage of a lien, security interest or encumbrance in or upon, or the gift, grant or placement in trust, or the Constructive Sale or other disposition of such security (including transfers by testamentary or intestate succession, by domestic relations order or other court order, or otherwise by operation of law) or any right, title or interest therein (including any right or power to vote to which the holder thereof may be entitled, whether such right or power is granted by proxy or otherwise), or the record or beneficial ownership thereof, the offer to make such a sale, transfer, Constructive Sale or other disposition, and each agreement, arrangement or understanding, whether or not in writing, to effect any of the foregoing.

2. Transfer and Voting Restrictions. The Stockholder covenants to the Company as follows:

(a) During the period commencing with the execution and delivery of this Agreement and expiring on the Expiration Date (as defined below), the Stockholder shall not Transfer any of the Stockholder’s Shares, or publicly announce its intention to Transfer any of its Shares.

(b) Except as otherwise permitted by this Agreement or by order of a court of competent jurisdiction, the Stockholder will not commit any act that would restrict the Stockholder’s legal power, authority and right to vote all of the Shares held by the Stockholder or otherwise prevent or disable the Stockholder from performing any of his, her or its obligations under this Agreement. Without limiting the generality of the foregoing, except for this Agreement and as otherwise permitted by this Agreement, the Stockholder shall not enter into any voting agreement with any person or entity with respect to any of the Stockholder’s Shares, grant any person or entity any proxy (revocable or irrevocable) or power of attorney with respect to any of the Shares, deposit any Shares in a voting trust or otherwise enter into any agreement or arrangement with any person or entity limiting or affecting the Stockholder’s legal power, authority or right to vote the Stockholder’s Shares in favor of the Magenta Stockholder Matters and against any competing proposals.

(c) Notwithstanding anything else herein to the contrary, the Stockholder may, at any time, Transfer Shares (i) by will or other testamentary document or by intestacy, (ii) to any investment fund or other entity controlled or managed by the Stockholder, (iii) to any member of the Stockholder’s immediate family or (iv) to any trust for the direct or indirect benefit of the Stockholder or the immediate family of the Stockholder or otherwise for estate planning purposes; provided, that (x) such Transferred Shares shall continue to be bound by this Agreement and (y) the applicable transferee shall have executed and delivered to Magenta and the Company a support agreement substantially identical to this Agreement upon consummation of the Transfer.

Exhibit A-1 – Page 2

3. Agreement to Vote Shares. The Stockholder covenants to the Company as follows:

(a) Until the Expiration Date (as defined below), at any meeting of the stockholders of Magenta, however called, and at every adjournment or postponement thereof, and on every action or approval by written consent of the stockholders of Magenta, the Stockholder shall be present (in person or by proxy) and vote, or exercise its right to consent with respect to, all Shares held by the Stockholder (A) in favor of the Magenta Stockholder Matters and (B) against any competing proposals.

(b) If the Stockholder is the beneficial owner, but not the record holder, of Shares, the Stockholder agrees to take all actions necessary to cause the record holder and any nominees to be present (in person or by proxy) and vote all the Stockholder’s Shares in accordance with this Section 3.

(c) In the event of a stock split, stock dividend or distribution, or any change in the capital stock of Magenta by reason of any split-up, reverse stock split, recapitalization, combination, reclassification, reincorporation, exchange of shares or the like, the term “Shares” shall be deemed to refer to and include such shares as well as all such stock dividends and distributions and any securities into which or for which any or all of such shares may be changed or exchanged or which are received in such transaction.

4. Action in Stockholder Capacity Only. The Stockholder is entering into this Agreement solely in the Stockholder’s capacity as a record holder and beneficial owner, as applicable, of its Shares and not in the Stockholder’s capacity as a director or officer of Magenta. Nothing herein shall limit or affect the Stockholder’s ability to act as an officer or director of Magenta.

5. Irrevocable Proxy. The Stockholder hereby revokes (or agrees to cause to be revoked) any proxies that the Stockholder has heretofore granted with respect to its Shares. In the event and to the extent that the Stockholder fails to vote the Shares in accordance with Section 3 at any applicable meeting of the stockholders of Magenta or pursuant to any applicable written consent of the stockholders of Magenta, the Stockholder shall be deemed to have irrevocably granted to, and appointed, the Company, and any individual designated in writing by the Company, and each of them individually, as his, her or its proxy and attorney-in-fact (with full power of substitution), for and in its name, place and stead, to vote his, her or its Shares in any action by written consent of Magenta stockholders or at any meeting of the Magenta stockholders called with respect to any of the matters specified in, and in accordance and consistent with, Section 3 of this Agreement. The Company agrees not to exercise the proxy granted herein for any purpose other than the purposes described in this Agreement. Except as otherwise provided for herein, the Stockholder hereby affirms that the irrevocable proxy is coupled with an interest and may under no circumstances be revoked and that such irrevocable proxy is executed and intended to be irrevocable. Notwithstanding any other provisions of this Agreement, the irrevocable proxy granted hereunder shall automatically terminate upon the termination of this Agreement.

6. No Solicitation. Subject to Section 4, the Stockholder agrees not to, directly or indirectly, including through any of its officers, directors or agents, (a) solicit, seek or initiate or knowingly take any action to facilitate or encourage, any offers, inquiries or the making of any proposal or offer that constitutes, or could reasonably be expected to lead to, any Acquisition Proposal or Acquisition Inquiry or (b) enter into, continue or otherwise participate or engage in any discussions or negotiations regarding any Acquisition Proposal, or furnish to any person any

Exhibit A-1 – Page 3

non-public information or afford any person, other than Magenta or the Company, as applicable, access to such party’s property, books or records (except pursuant to a request by a Governmental Authority) in connection with, any Acquisition Proposal; provided, however, that nothing in this Section 6 shall prevent the Stockholder from referring a person to this Section 6 or to the Merger Agreement.

7. Documentation and Information. The Stockholder shall permit and hereby authorizes Magenta and the Company to publish and disclose in all documents and schedules filed with the SEC, and any press release or other disclosure document that Magenta or the Company reasonably determines to be necessary in connection with the Merger and any of the Contemplated Transactions, a copy of this Agreement, the Stockholder’s identity and ownership of the Shares and the nature of the Stockholder’s commitments and obligations under this Agreement. Each of Magenta and the Company is an intended third-party beneficiary of this Section 7.

8. No Exercise of Appraisal Rights; Waivers. The Stockholder hereby irrevocably and unconditionally (a) waives, and agrees to cause to be waived and to prevent the exercise of, any rights of appraisal, any dissenters’ rights and any similar rights (including any notice requirements related thereto) relating to the Merger that Stockholder may have by virtue of, or with respect to, any Shares (including all rights under Section 262 of the DGCL) and (b) agrees that the Stockholder will not bring, commence, institute, maintain, prosecute or voluntarily aid or participate in any action, claim, suit or cause of action, in law or in equity, in any court or before any Governmental Authority, which (i) challenges the validity of or seeks to enjoin the operation of any provision of this Agreement or (ii) alleges that the execution and delivery of this Agreement by the Stockholder, or the approval of the Merger Agreement by the Magenta Board, breaches any fiduciary duty of the Magenta Board or any member thereof; provided, that the Stockholder may defend against, contest or settle any such action, claim, suit or cause of action brought against the Stockholder that relates solely to the Stockholder’s capacity as a director, officer or securityholder of Magenta.

9. Representations and Warranties of the Stockholder. The Stockholder hereby represents and warrants to the Company as follows:

(a) (i) The Stockholder is the beneficial or record owner of the shares of Magenta Common Stock indicated in Appendix A (each of which shall be deemed to be “held” by the Stockholder for purposes of Section 3 unless otherwise expressly stated with respect to any shares in Appendix A), free and clear of any and all Liens; and (ii) the Stockholder does not beneficially own any securities of Magenta other than the shares of Magenta Common Stock and rights to purchase shares Magenta Common Stock set forth in Appendix A.

(b) Except as otherwise provided in this Agreement, the Stockholder has full power and authority to (i) make, enter into and carry out the terms of this Agreement and (ii) vote all of its Shares in the manner set forth in this Agreement without the consent or approval of, or any other action on the part of, any other person or entity (including any Governmental Authority). Without limiting the generality of the foregoing, the Stockholder has not entered into any voting agreement (other than this Agreement) with any person with respect to any of the Stockholder’s Shares, granted any person any proxy (revocable or irrevocable) or power of attorney with respect to any of the Stockholder’s Shares, deposited any of the Stockholder’s Shares in a voting trust or entered into any arrangement or agreement with any person limiting or affecting the Stockholder’s legal power, authority or right to vote the Stockholder’s Shares on any matter.

Exhibit A-1 – Page 4

(c) This Agreement has been duly and validly executed and delivered by the Stockholder and (assuming the due authorization, execution and delivery by the other parties hereto) constitutes a valid and binding agreement of the Stockholder enforceable against the Stockholder in accordance with its terms, subject to the Enforceability Exceptions. The execution and delivery of this Agreement by the Stockholder and the performance by the Stockholder of the agreements and obligations hereunder will not result in any breach or violation of or be in conflict with or constitute a default under any term of any Contract or if applicable any provision of an organizational document (including a certificate of incorporation) to or by which the Stockholder is a party or bound, or any applicable law to which the Stockholder (or any of the Stockholder’s assets) is subject or bound, except for any such breach, violation, conflict or default which, individually or in the aggregate, would not reasonably be expected to materially impair or adversely affect the Stockholder’s ability to perform its obligations under this Agreement.

(d) The Stockholder has had the opportunity to review the Merger Agreement and this Agreement with the Stockholder’s legal counsel. The Stockholder understands and acknowledges that the Company is entering into the Merger Agreement in reliance upon the Stockholder’s execution, delivery and performance of this Agreement.

(e) The execution, delivery and performance of this Agreement by the Stockholder do not and will not require any consent, approval, authorization or permit of, action by, filing with or notification to, any Governmental Authority, except for any such consent, approval, authorization, permit, action, filing or notification the failure of which to make or obtain, individually or in the aggregate, has not and would not materially impair the Stockholder’s ability to perform its obligations under this Agreement.

(f) The Stockholder has had the opportunity to review the Merger Agreement and this Agreement with counsel of the Stockholder’s own choosing. The Stockholder has had an opportunity to review with its own tax advisors the tax consequences of the Merger and the Contemplated Transactions. The Stockholder understands that it must rely solely on its advisors and not on any statements or representations made by Magenta, the Company or any of their respective agents or representatives with respect to the tax consequences of the Merger and the Contemplated Transactions. The Stockholder understands that such Stockholder (and not Magenta, the Company or the Surviving Corporation) shall be responsible for such Stockholder’s tax liability that may arise as a result of the Merger or the Contemplated Transactions. The Stockholder understands and acknowledges that the Company, Magenta and Merger Sub are entering into the Merger Agreement in reliance upon the Stockholder’s execution, delivery and performance of this Agreement.

(g) With respect to the Stockholder, as of the date hereof, there is no action, suit, investigation or proceeding pending against, or, to the knowledge of the Stockholder, threatened against, the Stockholder or any of the Stockholder’s properties or assets (including the Shares) that would reasonably be expected to prevent or materially delay or impair the ability of the Stockholder to perform its obligations hereunder or to consummate the transactions contemplated hereby.

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10. Termination. This Agreement shall terminate and shall cease to be of any further force or effect as of the earlier of (a) such date and time as the Merger Agreement shall have been terminated pursuant to the terms thereof or (b) the Effective Time (the “Expiration Date”); provided, however, that (i) Section 11 shall survive the termination of this Agreement, and (ii) the termination of this Agreement shall not relieve any party hereto from any liability for any material and willful breach of this Agreement prior to the Effective Time.

11. Miscellaneous Provisions.

(a) Amendments. No amendment of this Agreement shall be effective against any party unless it shall be in writing and signed by each of the parties hereto.

(b) Entire Agreement; Counterparts; Exchanges by Electronic Transmission or Facsimile. This Agreement constitutes the entire agreement between the parties to this Agreement and supersedes all other prior agreements, arrangements and understandings, both written and oral, among the parties with respect to the subject matter hereof. This Agreement may be executed in several counterparts, each of which shall be deemed an original and all of which shall constitute one and the same instrument. The exchange of a fully executed Agreement (in counterparts or otherwise) by all parties by facsimile or electronic transmission in PDF format shall be sufficient to bind the parties to the terms and conditions of this Agreement.

(c) Applicable Law; Jurisdiction. This Agreement shall be governed by, and construed in accordance with, the laws of the State of Delaware, regardless of the laws that might otherwise govern under applicable principles of conflicts of laws. In any action or proceeding between any of the parties arising out of or relating to this Agreement, each of the parties: (i) irrevocably and unconditionally consents and submits to the exclusive jurisdiction and venue of the Court of Chancery of the State of Delaware or, to the extent such court does not have subject matter jurisdiction, the Superior Court of the State of Delaware or the United States District Court for the District of Delaware, (ii) agrees that all claims in respect of such action or proceeding shall be heard and determined exclusively in accordance with clause (a) of this Section 11(c), (iii) waives any objection to laying venue in any such action or proceeding in such courts, (iv) waives any objection that such courts are an inconvenient forum or do not have jurisdiction over any party, (v) agrees that service of process upon such party in any such action or proceeding shall be effective if notice is given in accordance with Section 11(k) of this Agreement and (vi) irrevocably and unconditionally waives the right to trial by jury.

(d) Assignment. This Agreement shall be binding upon, and shall be enforceable by and inure solely to the benefit of, the parties and their respective successors and permitted assigns; provided, however, that neither this Agreement nor any of a party’s rights or obligations hereunder may be assigned or delegated by such party without the prior written consent of the other party, and any attempted assignment or delegation of this Agreement or any of such rights or obligations by such party without the other party’s prior written consent shall be void and of no effect. Any purported assignment of rights or delegation of performance obligations in violation of this Section 11(d) is void.

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(e) No Third Party Rights. This Agreement is not intended to, and shall not, confer upon any other person any rights or remedies hereunder other than the parties hereto to the extent expressly set forth herein.

(f) Severability. Any term or provision of this Agreement that is invalid or unenforceable in any situation in any jurisdiction shall not affect the validity or enforceability of the remaining terms and provisions of this Agreement or the validity or enforceability of the offending term or provision in any other situation or in any other jurisdiction. If a final judgment of a court of competent jurisdiction declares that any term or provision of this Agreement is invalid or unenforceable, the Parties agree that the court making such determination shall have the power to limit such term or provision, to delete specific words or phrases or to replace such term or provision with a term or provision that is valid and enforceable and that comes closest to expressing the intention of the invalid or unenforceable term or provision, and this Agreement shall be valid and enforceable as so modified. In the event such court does not exercise the power granted to it in the prior sentence, the Parties agree to replace such invalid or unenforceable term or provision with a valid and enforceable term or provision that will achieve, to the extent possible, the economic, business and other purposes of such invalid or unenforceable term or provision.

(g) Specific Performance. Except as otherwise provided herein, any and all remedies herein expressly conferred upon a party will be deemed cumulative with and not exclusive of any other remedy conferred hereby, or by law or equity upon such party, and the exercise by a party of any one remedy will not preclude the exercise of any other remedy. The parties agree that irreparable damage for which monetary damages, even if available, would not be an adequate remedy, would occur in the event that any of the provisions of this Agreement were not performed in accordance with their specific terms (including failing to take such actions as are required of it hereunder to consummate this Agreement) or were otherwise breached. It is accordingly agreed that the parties shall be entitled to an injunction or injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions hereof in any court of the United States or any state having jurisdiction, this being in addition to any other remedy to which they are entitled at law or in equity, and each of the parties waives any bond, surety or other security that might be required of any other party with respect thereto. Each of the parties further agrees that it will not oppose the granting of an injunction, specific performance or other equitable relief on the basis that any other party has an adequate remedy at law or that any award of specific performance is not an appropriate remedy for any reason at law or in equity.

(h) Notices. All notices and other communications hereunder shall be in writing and shall be deemed duly delivered (i) one (1) Business Day after being sent for next Business Day delivery, fees prepaid, via a reputable international overnight courier service, (ii) upon delivery in the case of delivery by hand or (iii) on the date delivered in the place of delivery if sent by email or facsimile (with a written or electronic confirmation of delivery) prior to 6:00 p.m. (New York City time), otherwise on the next succeeding Business Day, (A) if to the Company or Magenta, to the address, electronic mail address or facsimile provided in the Merger Agreement, including to the persons designated therein to receive copies; and/or (B) if to the Stockholder, to the Stockholder’s address, electronic mail address or facsimile shown below Stockholder’s signature to this Agreement.

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(i) Confidentiality. Except to the extent required by applicable Law or regulation, the Stockholder shall hold any non-public information regarding this Agreement, the Merger Agreement and the Merger in strict confidence and shall not divulge any such information to any third person until Magenta has publicly disclosed its entry into the Merger Agreement and this Agreement; provided, however, that the Stockholder may disclose such information to its Affiliates, partners, members, stockholders, parents, subsidiaries, attorneys, accountants, consultants, trustees, beneficiaries and other representatives (provided that such Persons are subject to confidentiality obligations at least as restrictive as those contained herein). Neither the Stockholder nor any of its Affiliates (other than Magenta, whose actions shall be governed by the Merger Agreement), shall issue or cause the publication of any press release or other public announcement with respect to this Agreement, the Merger, the Merger Agreement or the other transactions contemplated hereby or thereby without the prior written consent of the Company and Magenta, except as may be required by applicable Law in which circumstance such announcing party shall make reasonable efforts to consult with the Company and Magenta to the extent practicable. The Company is an intended third-party beneficiary of this Section 11(i).

(j) Interpretation. When reference is made in this Agreement to a Section or Appendix, such reference shall be to a Section of or Appendix to this Agreement, unless otherwise indicated. The headings contained in this Agreement are for convenience of reference only and shall not affect in any way the meaning or interpretation of this Agreement. The language used in this Agreement shall be deemed to be the language chosen by the parties hereto to express their mutual intent, and no rule of strict construction shall be applied against any party. Whenever the context may require, any pronouns used in this Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular form of nouns and pronouns shall include the plural, and vice versa. Any reference to any federal, state, local or foreign statute or law shall be deemed also to refer to all rules and regulations promulgated thereunder, unless the context requires otherwise. Whenever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation.”

[Remainder of Page Left Intentionally Blank]

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IN WITNESS WHEREOF, the undersigned have caused this Agreement to be duly executed as of the date first above written.

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Appendix A

Exhibit A-2

FORM OF COMPANY STOCKHOLDER SUPPORT AGREEMENT

This Support Agreement (this “Agreement”) is made and entered into as of May 2, 2023, by and among Dianthus Therapeutics, Inc., a Delaware corporation (the “Company”), Magenta Therapeutics, Inc., a Delaware corporation (“Magenta”), and the undersigned stockholder (the “Stockholder”) of the Company. Capitalized terms used herein but not otherwise defined shall have the respective meanings ascribed to such terms in the Merger Agreement (as defined below).

RECITALS

WHEREAS, concurrently with the execution and delivery hereof, Magenta, the Company and Dio Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Magenta (the “Merger Sub”), have entered into an Agreement and Plan of Merger (as such agreement may be amended or supplemented from time to time pursuant to the terms thereof, the “Merger Agreement”), pursuant to which Merger Sub will merge with and into the Company, with the Company surviving the merger as the surviving corporation and a wholly owned subsidiary of Magenta (the “Merger”) upon the terms and subject to the conditions set forth in the Merger Agreement.

WHEREAS, as of the date hereof, the Stockholder is the beneficial owner (as defined in Rule 13d-3 under the Exchange Act) of such number of shares of Company Capital Stock as indicated in Appendix A.

WHEREAS, as an inducement to the willingness of Magenta to enter into the Merger Agreement, Magenta has required that Stockholder enter into this Agreement.

NOW, THEREFORE, intending to be legally bound, the parties hereby agree as follows:

1. Certain Definitions. Capitalized terms used but not otherwise defined herein shall have the meanings ascribed thereto in the Merger Agreement. For all purposes of this Agreement, the following terms shall have the following respective meanings:

(a) “Constructive Sale” means, with respect to any security, a short sale with respect to such security, entering into or acquiring a derivative contract with respect to such security, entering into or acquiring a futures or forward contract to deliver such security or entering into any other hedging or other derivative transaction that has the effect of either directly or indirectly materially changing the economic benefits or risks of ownership of such security.

(b) “Shares” means (i) all shares of Company Capital Stock beneficially owned by the Stockholder as of the date hereof, and (ii) all additional shares of Company Capital Stock acquired and beneficially owned by the Stockholder during the period commencing with the execution and delivery of this Agreement and expiring on the Closing Date.

(c) “Transfer” or “Transferred” means, with respect to any security, the direct or indirect assignment, sale, transfer, tender, exchange, pledge or hypothecation, or the grant, creation or suffrage of a lien, security interest or encumbrance in or upon, or the gift, grant or

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placement in trust, or the Constructive Sale or other disposition of such security (including transfers by testamentary or intestate succession, by domestic relations order or other court order, or otherwise by operation of law) or any right, title or interest therein (including any right or power to vote to which the holder thereof may be entitled, whether such right or power is granted by proxy or otherwise), or the beneficial ownership thereof, the offer to make such a sale, transfer, Constructive Sale or other disposition, and each agreement, arrangement or understanding, whether or not in writing, to effect any of the foregoing.

2. Transfer and Voting Restrictions. The Stockholder covenants to Magenta as follows:

(a) Except as otherwise permitted by Section 2(c), during the period commencing with the execution and delivery of this Agreement and expiring on the Expiration Date (as defined below), the Stockholder shall not Transfer any of the Stockholder’s Shares, or publicly announce its intention to Transfer any of its Shares.

(b) Except as otherwise permitted by this Agreement or otherwise permitted or required by order of a court of competent jurisdiction or a Governmental Authority, the Stockholder will not commit any act that would restrict the Stockholder’s legal power, authority and right to vote all of the Shares held by the Stockholder or otherwise prevent or disable the Stockholder from performing any of his, her or its obligations under this Agreement. Without limiting the generality of the foregoing, except for this Agreement, the Amended and Restated Voting Agreement of the Company, dated as of April 6, 2022 (the “Voting Agreement”) and as otherwise permitted by this Agreement, the Stockholder shall not enter into any voting agreement with any person or entity with respect to any of the Stockholder’s Shares, grant any person or entity any proxy (revocable or irrevocable) or power of attorney with respect to any of the Shares, deposit any Shares in a voting trust or otherwise enter into any agreement or arrangement with any person or entity limiting or affecting the Stockholder’s legal power, authority or right to execute and deliver the Company Stockholder Written Consent.

(c) Notwithstanding anything else herein to the contrary, the Stockholder may, at any time, Transfer Shares (i) by will or other testamentary document or by intestacy, (ii) to any investment fund or other entity controlled or managed by the Stockholder or the investment adviser of general partner of the Stockholder, or an entity under common control or management with the Stockholders (in each case, directly or indirectly) (iii) to any member of the Stockholder’s immediate family (or, if the Stockholder is a corporation, partnership or other entity, to an immediate family member of a beneficial owner of the Shares held by the Stockholder), (iv) to any trust or other entity for the direct or indirect benefit of the Stockholder or the immediate family of the Stockholder (or, if the Stockholder is a corporation, partnership or other entity, for the direct or indirect benefit of an immediate family member of a beneficial owner of the Shares held by the Stockholder) or otherwise for estate tax or estate planning purposes, (v) in the case of a Stockholder who is not a natural person, by pro rata distributions from the Stockholder to its members, partners, or shareholders pursuant to the Stockholder’s organizational documents; provided, that in the cases of clauses (i)-(v), (x) such Transferred Shares shall continue to be bound by this Agreement and (y) the applicable direct transferee (if any) of such Transferred Shares shall have executed and delivered to Magenta and the Company a support agreement substantially identical to this Agreement upon consummation of the Transfer or (vi) to the extent required by applicable Law.

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(d) Notwithstanding anything to the contrary herein, nothing in this Agreement shall obligate the Stockholder to exercise any option or any other right to acquire any shares of Company Capital Stock.

3. Agreement to Vote Shares. The Stockholder covenants to the Company as follows:

(a) Until the Expiration Date, at any meeting of the stockholders of the Company, however called, and at every adjournment or postponement thereof, and on every action or approval by written consent of the stockholders of the Company, the Stockholder shall be present (in person or by proxy) and vote, or exercise its right to consent with respect to, all Shares held by the Stockholder (A) in favor of the adoption and approval of the Merger Agreement, (B) in favor of approval of the Contemplated Transactions, and (C) against any Acquisition Proposal.

(b) If the Stockholder is not the record holder, of Shares, the Stockholder agrees to take all actions necessary to cause the record holder and any nominees to be present (in person or by proxy) and vote all the Stockholder’s Shares in accordance with this Section 3.

(c) In the event of a stock split, stock dividend or distribution, or any change in the capital stock of the Company by reason of any split-up, reverse stock split, recapitalization, combination, reclassification, reincorporation, exchange of shares or the like, the term “Shares” shall be deemed to refer to and include such shares as well as all such stock dividends and distributions and any securities into which or for which any or all of such shares may be changed or exchanged or which are received in such transaction.

4. Action in Stockholder Capacity Only. The Stockholder is entering into this Agreement solely in the Stockholder’s capacity as the beneficial owner of its Shares and not in the Stockholder’s capacity as a director or officer of the Company. Nothing herein shall limit or affect the Stockholder’s ability to act as an officer or director of the Company.

5. Irrevocable Proxy. The Stockholder hereby revokes (or agrees to cause to be revoked) any proxies that the Stockholder has heretofore granted with respect to its Shares. In the event and to the extent that the Stockholder fails to vote the Shares in accordance with Section 3 at any applicable meeting of the stockholders of the Company or pursuant to any applicable written consent of the stockholders of the Company, the Stockholder shall be deemed to have irrevocably granted to, and appointed, the Company, and any individual designated in writing by it, and each of them individually, as his, her or its proxy and attorney-in-fact (with full power of substitution), for and in its name, place and stead, to vote his, her or its Shares in any action by written consent of Company stockholders or at any meeting of the Company stockholders called with respect to any of the matters specified in, and in accordance and consistent with, Section 3 of this Agreement. The Company agrees not to exercise the proxy granted herein for any purpose other than the purposes described in this Agreement. Except as otherwise provided for herein (including the next sentence), the Stockholder hereby affirms that

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the irrevocable proxy is coupled with an interest and may under no circumstances be revoked and that such irrevocable proxy is executed and intended to be irrevocable. Notwithstanding any other provisions of this Agreement, the irrevocable proxy granted hereunder shall automatically terminate upon the termination of this Agreement.

6. No Solicitation. Subject to Section 4, the Stockholder agrees not to, directly or indirectly, including through any of its officers, directors or agents, (a) solicit, seek or initiate or knowingly take any action to facilitate or encourage, any offers, inquiries or the making of any proposal or offer that constitutes, or could reasonably be expected to lead to, any Acquisition Proposal or Acquisition Inquiry or (b) enter into, continue or otherwise participate or engage in any discussions or negotiations regarding any Acquisition Proposal, or furnish to any person any non-public information or afford any person, other than Magenta or the Company, as applicable, access to such party’s property, books or records (except as required by applicable Law or pursuant to a request by a Governmental Authority) in connection with, any Acquisition Proposal; provided, however, that nothing in this Section 6 shall prevent the Stockholder from referring a person to this Section 6 or to the Merger Agreement.

7. Documentation and Information. The Stockholder shall permit and hereby authorizes Magenta and the Company to publish and disclose in all documents and schedules filed with the SEC, and any press release or other disclosure document that Magenta or the Company reasonably determines to be necessary in connection with the Merger and any of the Contemplated Transactions, a copy of this Agreement, the Stockholder’s identity and ownership of the Shares and the nature of the Stockholder’s commitments and obligations under this Agreement; provided, that, Magenta and the Company provide such documents, schedules, press release or other disclosure document to the Stockholder in advance for its review and comment. Each of Magenta and the Company is an intended third-party beneficiary of this Section 7.

8. No Exercise of Appraisal Rights; Waivers. The Stockholder hereby irrevocably and unconditionally (a) waives, and agrees to cause to be waived and to prevent the exercise of, any rights of appraisal, any dissenters’ rights and any similar rights (including any notice requirements related thereto) relating to the Merger that Stockholder may have by virtue of, or with respect to, any Shares (including all rights under Section 262 of the DGCL) and (b) agrees that the Stockholder will not bring, commence, institute, maintain, prosecute or voluntarily aid or participate in any action, claim, suit or cause of action, in law or in equity, in any court or before any Governmental Authority, which (i) challenges the validity of or seeks to enjoin the operation of any provision of this Agreement or (ii) alleges that the execution and delivery of this Agreement by the Stockholder breaches any duty that such Stockholder has (or may be alleged to have) to the Company or to the other Company stockholders; provided, that (x) the Stockholder may defend against, contest or settle any such action, claim, suit or cause of action brought against the Stockholder that relates solely to the Stockholder’s capacity as a director, officer or securityholder of the Company and (y) the foregoing shall not limit or restrict in any manner the Stockholder from enforcing the Stockholder’s rights under this Agreement and the other agreements entered into by the Stockholder in connection herewith, or otherwise in connection with the Merger, including the Stockholder’s right to receive the Merger Consideration pursuant to the terms of the Merger Agreement.

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9. Representations and Warranties of the Stockholder. The Stockholder hereby represents and warrants to the Company as follows:

(a) (i) The Stockholder is the beneficial owner of the shares of Company Capital Stock indicated in Appendix A (each of which shall be deemed to be “held” by the Stockholder for purposes of Section 3 unless otherwise expressly stated with respect to any shares in Appendix A), free and clear of any and all Encumbrances (except for any Encumbrance that may be imposed pursuant to this Agreement, the Voting Agreement, the Investors’ Rights Agreement of the Company, dated as of April 6, 2022 (the “Investors’ Rights Agreement”) or any lock-up agreement entered into by and between the Stockholder, the Company and Magenta); and (ii) the Stockholder does not beneficially own any securities of the Company other than the shares of Company Capital Stock and rights to purchase shares Company Capital Stock set forth in Appendix A.

(b) Except as otherwise provided in this Agreement, the Stockholder has full power and authority to (i) make, enter into and carry out the terms of this Agreement and (ii) vote all of its Shares in the manner set forth in this Agreement without the consent or approval of, or any other action on the part of, any other person or entity (including any Governmental Authority). Without limiting the generality of the foregoing, except for the Voting Agreement, the Stockholder has not entered into any voting agreement (other than this Agreement) with any person with respect to any of the Stockholder’s Shares, granted any person any proxy (revocable or irrevocable) or power of attorney with respect to any of the Stockholder’s Shares, deposited any of the Stockholder’s Shares in a voting trust or entered into any arrangement or agreement with any person limiting or affecting the Stockholder’s legal power, authority or right to vote the Stockholder’s Shares on any matter.

(c) This Agreement has been duly and validly executed and delivered by the Stockholder and (assuming the due authorization, execution and delivery by the other parties hereto) constitutes a valid and binding agreement of the Stockholder enforceable against the Stockholder in accordance with its terms, subject to the Enforceability Exceptions. The execution and delivery of this Agreement by the Stockholder and the performance by the Stockholder of the agreements and obligations hereunder will not result in any breach or violation of or be in conflict with or constitute a default under any term of any Contract or if applicable any provision of an organizational document (including a certificate of incorporation) to or by which the Stockholder is a party or bound, or any applicable law to which the Stockholder (or any of the Stockholder’s assets) is subject or bound, except for any such breach, violation, conflict or default which, individually or in the aggregate, would not reasonably be expected to materially impair or adversely affect the Stockholder’s ability to perform its obligations under this Agreement.

(d) The execution, delivery and performance of this Agreement by the Stockholder do not and will not require any consent, approval, authorization or permit of, action by, filing with or notification to, any Governmental Authority, except for any such consent, approval, authorization, permit, action, filing or notification the failure of which to make or obtain, individually or in the aggregate, has not and would not materially impair the Stockholder’s ability to perform its obligations under this Agreement.

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(e) The Stockholder has had the opportunity to review the Merger Agreement and this Agreement with counsel of the Stockholder’s own choosing. The Stockholder has had an opportunity to review with its own tax advisors the tax consequences of the Merger and the Contemplated Transactions. The Stockholder understands that it must rely solely on its advisors and not on any statements or representations made by Magenta, the Company or any of their respective agents or representatives with respect to the tax consequences of the Merger and the Contemplated Transactions. The Stockholder understands that such Stockholder (and not Magenta, the Company or the Surviving Corporation) shall be responsible for such Stockholder’s tax liability that may arise as a result of the Merger or the Contemplated Transactions. The Stockholder understands and acknowledges that the Company, Magenta and Merger Sub are entering into the Merger Agreement in reliance upon the Stockholder’s execution, delivery and performance of this Agreement.

(f) With respect to the Stockholder, as of the date hereof, there is no action, suit, investigation or proceeding pending against, or, to the knowledge of the Stockholder, threatened against, the Stockholder or any of the Stockholder’s properties or assets (including the Shares) that would reasonably be expected to prevent or materially delay or impair the ability of the Stockholder to perform its obligations hereunder or to consummate the transactions contemplated hereby.

10. Certain Agreements. Each Stockholder, by this Agreement, and with respect to such Stockholder’s Shares, severally and not jointly, hereby agrees to terminate, subject to the occurrence of, and effective immediately prior to, the Effective Time each of (a) the Voting Agreement, the Investors’ Rights Agreement and the Amended and Restated Right of First Refusal and Co-Sale Agreement, dated April 6, 2022, between the Company and the other parties thereto and (b) any rights under any letter agreement providing for redemption rights, put rights, purchase rights, information rights, rights to consult with and advise management, inspection rights, preemptive rights, board of directors observer rights or rights to receive information delivered to the board of directors or other similar rights not generally available to stockholders of the Company between the Stockholder and the Company, but excluding, for the avoidance of doubt, any rights the Stockholder may have that relate to any indemnification, commercial, development or employment agreements or arrangements between such Stockholder and the Company or any subsidiary of the Company, which shall survive in accordance with their terms. Each Stockholder hereby terminates and waives all rights of first refusal, redemption rights and rights of notice of the Merger and the other transactions contemplated by the Merger Agreement, effective as of immediately prior to, and contingent upon, the Effective Time.

11. Termination. This Agreement shall terminate and shall cease to be of any further force or effect as of the earliest of (a) such date and time as the Merger Agreement shall have been terminated pursuant to the terms thereof as in effect on the date of this Agreement (and without giving effect to any amendments thereto unless consented to by the Stockholder), (b) the Effective Time and (c) the time this Agreement is terminated upon the written agreement of the Stockholder, the Company and Magenta (the “Expiration Date”); provided, however, that (i) Section 12 shall survive the termination of this Agreement, and (ii) the termination of this Agreement shall not relieve any party hereto from any liability for any material and willful breach of this Agreement prior to the Effective Time.

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12. Miscellaneous Provisions.

(a) Amendments. No amendment of this Agreement shall be effective against any party unless it shall be in writing and signed by each of the parties hereto.

(b) Entire Agreement; Counterparts; Exchanges by Electronic Transmission or Facsimile. This Agreement constitutes the entire agreement between the parties to this Agreement and supersedes all other prior agreements, arrangements and understandings, both written and oral, among the parties with respect to the subject matter hereof. This Agreement may be executed in several counterparts, each of which shall be deemed an original and all of which shall constitute one and the same instrument. The exchange of a fully executed Agreement (in counterparts or otherwise) by all parties by facsimile or electronic transmission in PDF format shall be sufficient to bind the parties to the terms and conditions of this Agreement.

(c) Applicable Law; Jurisdiction. This Agreement shall be governed by, and construed in accordance with, the laws of the State of Delaware, regardless of the laws that might otherwise govern under applicable principles of conflicts of laws. In any action or proceeding between any of the parties arising out of or relating to this Agreement, each of the parties: (i) irrevocably and unconditionally consents and submits to the exclusive jurisdiction and venue of the Court of Chancery of the State of Delaware or, to the extent such court does not have subject matter jurisdiction, the Superior Court of the State of Delaware or the United States District Court for the District of Delaware, (ii) agrees that all claims in respect of such action or proceeding shall be heard and determined exclusively in accordance with clause (a) of this Section 12(c), (iii) waives any objection to laying venue in any such action or proceeding in such courts, (iv) waives any objection that such courts are an inconvenient forum or do not have jurisdiction over any party, (v) agrees that service of process upon such party in any such action or proceeding shall be effective if notice is given in accordance with Section 12(k) of this Agreement and (vi) irrevocably and unconditionally waives the right to trial by jury.

(d) Assignment. This Agreement shall be binding upon, and shall be enforceable by and inure solely to the benefit of, the parties and their respective successors and permitted assigns; provided, however, that neither this Agreement nor any of a party’s rights or obligations hereunder may be assigned or delegated by such party without the prior written consent of the other party (in whole or in part, whether by operation of law or otherwise), and any attempted or purported assignment or delegation of this Agreement or any of such rights or obligations by such party without the other party’s prior written consent shall be void and of no effect.

(e) No Third Party Rights. This Agreement is not intended to, and shall not, confer upon any other person any rights or remedies hereunder other than the parties hereto to the extent expressly set forth herein.

(f) Severability. Any term or provision of this Agreement that is invalid or unenforceable in any situation in any jurisdiction shall not affect the validity or enforceability of the remaining terms and provisions of this Agreement or the validity or enforceability of the offending term or provision in any other situation or in any other jurisdiction. If a final judgment of a court of competent jurisdiction declares that any term or provision of this Agreement is invalid or unenforceable, the Parties agree that the court making such determination shall have the power

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to limit such term or provision, to delete specific words or phrases or to replace such term or provision with a term or provision that is valid and enforceable and that comes closest to expressing the intention of the invalid or unenforceable term or provision, and this Agreement shall be valid and enforceable as so modified. In the event such court does not exercise the power granted to it in the prior sentence, the Parties agree to replace such invalid or unenforceable term or provision with a valid and enforceable term or provision that will achieve, to the extent possible, the economic, business and other purposes of such invalid or unenforceable term or provision.

(g) Specific Performance. Except as otherwise provided herein, any and all remedies herein expressly conferred upon a party will be deemed cumulative with and not exclusive of any other remedy conferred hereby, or by law or equity upon such party, and the exercise by a party of any one remedy will not preclude the exercise of any other remedy. The parties agree that irreparable damage for which monetary damages, even if available, would not be an adequate remedy, would occur in the event that any of the provisions of this Agreement were not performed in accordance with their specific terms (including failing to take such actions as are required of it hereunder to consummate this Agreement) or were otherwise breached. It is accordingly agreed that the parties shall be entitled to an injunction or injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions hereof in any court of the United States or any state having jurisdiction, this being in addition to any other remedy to which they are entitled at law or in equity, and each of the parties waives any bond, surety or other security that might be required of any other party with respect thereto. Each of the parties further agrees that it will not oppose the granting of an injunction, specific performance or other equitable relief on the basis that any other party has an adequate remedy at law or that any award of specific performance is not an appropriate remedy for any reason at law or in equity.

(h) Notices. All notices and other communications hereunder shall be in writing and shall be deemed duly delivered (i) one (1) Business Day after being sent for next Business Day delivery, fees prepaid, via a reputable international overnight courier service, (ii) upon delivery in the case of delivery by hand or (iii) on the date delivered in the place of delivery if sent by email or facsimile (with a written or electronic confirmation of delivery) prior to 6:00 p.m. (New York City time), otherwise on the next succeeding Business Day, (A) if to the Company or Magenta, to the address, electronic mail address or facsimile provided in the Merger Agreement, including to the persons designated therein to receive copies; and/or (B) if to the Stockholder, to the Stockholder’s address, electronic mail address or facsimile shown below Stockholder’s signature to this Agreement.

(i) Confidentiality. Except to the extent required by applicable Law or regulation, the Stockholder shall hold any non-public information regarding this Agreement, the Merger Agreement and the Merger in strict confidence and shall not divulge any such information to any third person until Magenta has publicly disclosed its entry into the Merger Agreement and this Agreement; provided, however, that the Stockholder may disclose such information to its Affiliates, partners, members, stockholders, parents, subsidiaries, attorneys, accountants, consultants, trustees, beneficiaries and other representatives (provided that such Persons are subject to confidentiality obligations at least as restrictive as those contained herein) or as otherwise permitted pursuant to and in accordance with the terms of Section 3.5 of the Investors’ Rights Agreement. Neither the Stockholder nor any of its Affiliates (other than Magenta, whose actions shall be governed by the Merger Agreement), shall issue or cause the publication of any

Exhibit A-2 – Page 8

press release or other public announcement with respect to this Agreement, the Merger, the Merger Agreement or the other transactions contemplated hereby or thereby without the prior written consent of the Company and Magenta, except as may be required by applicable Law in which circumstance such announcing party shall make reasonable efforts to consult with the Company and Magenta to the extent practicable. The Company is an intended third-party beneficiary of this Section 12(i).

(j) Interpretation. When reference is made in this Agreement to a Section or Appendix, such reference shall be to a Section of or Appendix to this Agreement, unless otherwise indicated. The headings contained in this Agreement are for convenience of reference only and shall not affect in any way the meaning or interpretation of this Agreement. The language used in this Agreement shall be deemed to be the language chosen by the parties hereto to express their mutual intent, and no rule of strict construction shall be applied against any party. Whenever the context may require, any pronouns used in this Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular form of nouns and pronouns shall include the plural, and vice versa. Any reference to any federal, state, local or foreign statute or law shall be deemed also to refer to all rules and regulations promulgated thereunder, unless the context requires otherwise. Whenever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation.”

[Remainder of Page Left Intentionally Blank]

Exhibit A-2 – Page 9

IN WITNESS WHEREOF, the undersigned have caused this Agreement to be duly executed as of the date first above written.

Exhibit A-2 – Page 10

Appendix A

Exhibit B

FORM OF LOCK-UP AGREEMENT

May 2, 2023

Magenta Therapeutics, Inc.

300 Technology Square, 8th Floor

Cambridge, Massachusetts 02139

Ladies and Gentlemen:

The undersigned signatory of this lock-up agreement (this “Lock-Up Agreement”) understands that Magenta Therapeutics, Inc., a Delaware corporation (“Magenta”), has entered into an Agreement and Plan of Merger, dated as of May 2, 2023 (as the same may be amended from time to time, the “Merger Agreement”) with Dio Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Magenta, and Dianthus Therapeutics, Inc., a Delaware corporation (the “Company”). Capitalized terms used but not otherwise defined herein shall have the respective meanings ascribed to such terms in the Merger Agreement.

As a condition and inducement to Magenta to enter into the Merger Agreement and to consummate the transactions contemplated thereby, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the undersigned hereby irrevocably agrees that, subject to the exceptions set forth herein, without the prior written consent of Magenta, the undersigned will not, during the period commencing upon the Closing and ending on the date that is 180 days after the Closing Date (the “Restricted Period”):

(1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, or otherwise transfer or dispose of, directly or indirectly, any shares of Magenta Common Stock or any securities convertible into or exercisable or exchangeable for shares of Magenta Common Stock (including without limitation, shares of Magenta Common Stock or such other securities which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations of the SEC and securities of Mammoth which may be issued upon exercise of an option to purchase shares of Magenta Common Stock or a warrant to purchase shares of Magenta Common Stock) that are currently or hereafter owned by the undersigned, except as set forth below (collectively, the “Undersigned’s Shares”);

(2) enter into any swap, short sale, hedge or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of the Undersigned’s Shares regardless of whether any such transaction described in clause (1) above or this clause (2) is to be settled by delivery of shares of Magenta Common Stock or other securities, in cash or otherwise;

(3) make any demand for, or exercise any right with respect to, the registration of any shares of Magenta Common Stock or any security convertible into or exercisable or exchangeable for shares of Magenta Common Stock (other than such rights set forth in the Merger Agreement); or

(4) publicly disclose the intention to do any of the foregoing.

Exhibit B – Page 1

The restrictions and obligations contemplated by this Lock-Up Agreement shall not apply to:

(a) transfers of the Undersigned’s Shares:

(1) (A) to any person related to the undersigned (or to an ultimate beneficial owner of the undersigned) by blood or adoption who is an immediate family member of the undersigned, or by marriage or domestic partnership (a “Family Member”), or to a trust formed for the benefit of the undersigned or any of the undersigned’s Family Members, (B) to the undersigned’s estate, following the death of the undersigned, by will, intestacy or other operation of Law, (C) as a bona fide gift or a charitable contribution, (D) by operation of Law pursuant to a qualified domestic order or in connection with a divorce settlement or (E) to any partnership, corporation or limited liability company which is controlled by or under common control with the undersigned and/or by any such Family Member(s);

(2) if the undersigned is a corporation, partnership, limited liability company or other entity, (A) to another corporation, partnership, limited liability company or other entity that is a direct or indirect affiliate (as defined under Rule 12b-2 of the Exchange Act) of the undersigned, including investment funds or other entities that controls or manages, is under common control or management with, or is controlled or managed by, the undersigned, (B) as a distribution or dividend to equity holders, current or former general or limited partners, members or managers (or to the estates of any of the foregoing), as applicable, of the undersigned (including upon the liquidation and dissolution of the undersigned pursuant to a plan of liquidation approved by the undersigned’s equity holders), (C) as a bona fide gift or a charitable contribution or otherwise to a trust or other entity for the direct or indirect benefit of an immediate family member of a beneficial owner (as defined in Rule 13d-3 of the Exchange Act) of the Undersigned’s Shares or (D) transfers or dispositions not involving a change in beneficial ownership; or

(3) if the undersigned is a trust, to any grantors or beneficiaries of the trust;

provided that, in the case of any transfer or distribution pursuant to this clause (a), such transfer is not for value (other than transfers pursuant to 1(A), 1(E) or 2(A)) and each donee, heir, beneficiary or other transferee or distributee shall sign and deliver to Magenta a lock-up agreement in the form of this Lock-Up Agreement with respect to the shares of Magenta Common Stock or such other securities that have been so transferred or distributed;

(b) the exercise of an option to purchase shares of Magenta Common Stock (including a net or cashless exercise of an option to purchase shares of Magenta Common Stock ), and any related transfer of shares of Magenta Common Stock to Magenta for the purpose of paying the exercise price of such options or for paying taxes (including estimated taxes) due as a result of the exercise of such options or for paying taxes (including estimated taxes) due as a result of the exercise of such options; provided that, for the avoidance of doubt, the underlying shares of Magenta Common Stock shall continue to be subject to the restrictions on transfer set forth in this Lock-Up Agreement;

Exhibit B – Page 2

(c) transfers to Magenta in connection with the net settlement of any other equity award that represents the right to receive in the future shares of Magenta Common Stock, settled in shares of Magenta Common Stock, to pay any tax withholding obligations; provided that, for the avoidance of doubt, the underlying shares of Magenta Common Stock shall continue to be subject to the restrictions on transfer set forth in this Lock-Up Agreement;

(d) the establishment of a trading plan pursuant to Rule 10b5-1 under the Exchange Act for the transfer of shares of Magenta Common Stock; provided that such plan does not provide for any transfers of shares of Magenta Common Stock during the Restricted Period;

(e) transfers by the undersigned of shares of Magenta Common Stock purchased by the undersigned on the open market or in a public offering by Mammoth, in each case following the Effective Time;

(f) pursuant to a bona-fide third party tender offer, merger, consolidation or other similar transaction made to all holders of Magenta’s capital stock involving a change of control of Magenta, provided that in the event that such tender offer, merger, consolidation or other such transaction is not completed, the Undersigned’s Shares shall remain subject to the restrictions contained in this Lock-Up Agreement;

(g) pursuant to an order of a court or regulatory agency; or

(h) transfers by the undersigned of shares of Magenta Common Stock issued pursuant to the Merger Agreement in respect of shares of the Company, if any, purchased from the Company on or about the Closing Date but prior to the Closing.

and provided, further, that, with respect to each of (b), (c), and (d) above, no filing by any party (including any donor, donee, transferor, transferee, distributor or distributee) under Section 16 of the Exchange Act or other public announcement shall be made voluntarily reporting a reduction in beneficial ownership of shares of Magenta Common Stock or any securities convertible into or exercisable or exchangeable for Magenta Common Stock in connection with such transfer or disposition during the Restricted Period (other than any exit filings) and if any filings under Section 16(a) of the Exchange Act, or other public filing, report or announcement reporting a reduction in beneficial ownership of shares of Magenta Common Stock in connection with such transfer or distribution, shall be legally required during the Restricted Period, such filing, report or announcement shall clearly indicate in the footnotes therein, in reasonable detail, a description of the circumstances of the transfer and that the shares remain subject to the lock-up agreement.

For purposes of this Lock-Up Agreement, “change of control” shall mean the transfer (whether by tender offer, merger, consolidation or other similar transaction), in one transaction or a series of related transactions, to a person or group of affiliated persons, of the Company’s voting securities if, after such transfer, the Company’s stockholders as of immediately prior to such transfer do not hold a majority of the outstanding voting securities of the Company (or the surviving entity).

Any attempted transfer in violation of this Lock-Up Agreement will be of no effect and null and void, regardless of whether the purported transferee has any actual or constructive knowledge of the transfer restrictions set forth in this Lock-Up Agreement, and will not be recorded on the share register of Magenta. In furtherance of the foregoing, the undersigned agrees that Magentaand any duly appointed transfer agent for the registration or transfer of the securities

Exhibit B – Page 3

described herein are hereby authorized to decline to make any transfer of securities if such transfer would constitute a violation or breach of this Lock-Up Agreement. Magenta may cause the legend set forth below, or a legend substantially equivalent thereto, to be placed upon any certificate(s) or other documents, ledgers or instruments evidencing the undersigned’s ownership of Magenta Common Stock:

THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO AND MAY ONLY BE TRANSFERRED IN COMPLIANCE WITH A LOCK-UP AGREEMENT, A COPY OF WHICH IS ON FILE AT THE PRINCIPAL OFFICE OF THE COMPANY.

The undersigned hereby represents and warrants that the undersigned has full power and authority to enter into this Lock-Up Agreement. All authority herein conferred or agreed to be conferred and any obligations of the undersigned shall be binding upon the successors, assigns, heirs or personal representatives of the undersigned.

The undersigned understands that if the Merger Agreement is terminated for any reason, the undersigned shall be released from all obligations under this Lock-Up Agreement. The undersigned understands that Magenta is proceeding with the transactions contemplated by the Merger Agreement in reliance upon this Lock-Up Agreement.

Except as otherwise provided herein, any and all remedies herein expressly conferred upon a party will be deemed cumulative with and not exclusive of any other remedy conferred hereby, or by law or equity upon such party, and the exercise by a party of any one remedy will not preclude the exercise of any other remedy. The parties agree that irreparable damage for which monetary damages, even if available, would not be an adequate remedy, would occur in the event that any of the provisions of this Lock-Up Agreement were not performed in accordance with their specific terms (including failing to take such actions as are required of it hereunder to consummate this Agreement) or were otherwise breached. It is accordingly agreed that the parties shall be entitled to an injunction or injunctions to prevent breaches of this Lock-Up Agreement and to enforce specifically the terms and provisions hereof in any court of the United States or any state having jurisdiction, this being in addition to any other remedy to which they are entitled at law or in equity, and each of the parties waives any bond, surety or other security that might be required of any other party with respect thereto. Each of the parties further agrees that it will not oppose the granting of an injunction, specific performance or other equitable relief on the basis that any other party has an adequate remedy at law or that any award of specific performance is not an appropriate remedy for any reason at law or in equity.

In the event that any holder of Magenta’s securities that are subject to a substantially similar agreement entered into by such holder, other than the undersigned, is permitted by Magenta to sell or otherwise transfer or dispose of shares of Magenta Common Stock for value other than as permitted by this or a substantially similar agreement entered into by such holder (whether in one or multiple releases or waivers), the same percentage of shares of Magenta Common Stock held by the undersigned on the date of such release or waiver as the percentage of the total number of outstanding shares of Magenta Common Stock held by such holder on the date of such release or waiver that are the subject of such release or waiver shall be immediately and fully released on

Exhibit B – Page 4

the same terms from any remaining restrictions set forth herein (the “Pro-Rata Release”); provided, however, that such Pro-Rata Release shall not be applied unless and until permission has been granted by Magenta to an equity holder or equity holders to sell or otherwise transfer or dispose of all or a portion of such equity holders shares of Magenta Common Stock in an aggregate amount in excess of 1% of the number of shares of Magenta Common Stock subject to a substantially similar agreement. In the event of any Pro-Rata Release, the Company shall promptly (and in any event within two (2) business days of such release) inform each relevant holder of Magenta Common Stock of the terms of such Pro-Rata Release.

Upon the release of any of the Undersigned’s Shares from this Lock-Up Agreement, Magenta will reasonably cooperate with the undersigned to facilitate the timely preparation and delivery of certificates representing the Undersigned Shares without the restrictive legend above or the withdrawal of any stop transfer instructions by virtue of this Lock-Up Agreement.

This Lock-Up Agreement shall be governed by, and construed in accordance with, the laws of the State of Delaware, regardless of the laws that might otherwise govern under applicable principles of conflicts of laws. In any action or proceeding between any of the parties arising out of or relating to this Lock-Up Agreement, each of the parties: (i) irrevocably and unconditionally consents and submits to the exclusive jurisdiction and venue of the Court of Chancery of the State of Delaware or, to the extent such court does not have subject matter jurisdiction, the Superior Court of the State of Delaware or the United States District Court for the District of Delaware, (ii) agrees that all claims in respect of such action or proceeding shall be heard and determined exclusively in accordance with foregoing clause (i) of this paragraph, (iii) waives any objection to laying venue in any such action or proceeding in such courts, (iv) waives any objection that such courts are an inconvenient forum or do not have jurisdiction over any party and (v) irrevocably and unconditionally waives the right to trial by jury. This Lock-Up Agreement constitutes the entire agreement between the parties to this Lock-Up Agreement and supersedes all other prior agreements, arrangements and understandings, both written and oral, among the parties with respect to the subject matter hereof. This Lock-Up Agreement may be executed in several counterparts, each of which shall be deemed an original and all of which shall constitute one and the same instrument. The exchange of a fully executed Lock-Up Agreement (in counterparts or otherwise) by all parties by facsimile or electronic transmission in PDF format shall be sufficient to bind the parties to the terms and conditions of this Agreement.

[SIGNATURE PAGE FOLLOWS]

Print Name of Stockholder:

[Signature Page to Lock-Up Agreement]

[Signature Page to Lock-Up Agreement]

Exhibit C

EXHIBIT C – FORM OF SUBSCRIPTION AGREEMENT

This Subscription Agreement (this “Agreement”) is made and entered into as of May 2, 2023 (the “Effective Date”) by and among Dianthus Therapeutics, Inc., a Delaware corporation (the “Company”), and each of the purchasers listed on the signature pages hereto, severally and not jointly (each a “Purchaser” and together the “Purchasers”). Certain terms used and not otherwise defined in the text of this Agreement are defined in Section 8 hereof.

RECITALS

WHEREAS, the Company is party to that certain Agreement and Plan of Merger by and among the Company, Dio Merger Sub, Inc. (“Merger Sub”), and Magenta Therapeutics, Inc. (“Magenta”), dated on or about the date hereof (the “Merger Agreement”), pursuant to which the Company will merge with and into Merger Sub and become a wholly-owned subsidiary of Magenta (the “Merger”);

WHEREAS, the Company desires to sell to the Purchasers, and the Purchasers, severally and not jointly, desire to purchase from the Company, an aggregate amount equal to $70,000,000 of (i) shares of the Company’s Common Stock, par value $0.0001 per share (the “Common Stock”) and (ii) if applicable, pre-funded warrants, in the form agreed (acting reasonably) between the Company and the applicable Purchasers, (the “Pre-Funded Warrants”) to acquire that number of shares of Common Stock, at a per share purchase price equal to the Purchase Price, in accordance with the terms and provisions of this Agreement, immediately prior to, but subject to, the closing of the Merger; and

WHEREAS, the Company and each Purchaser is executing and delivering this Agreement in reliance upon the exemption from securities registration afforded by Section 4(a)(2) of the 1933 Act;

NOW, THEREFORE, in consideration of the foregoing and the mutual representations, warranties and covenants herein contained, the parties hereto hereby agree as follows:

SECTION 1.    Authorization of Securities.

1.01    The Company has authorized the sale and issuance of shares of Common Stock on the terms and subject to the conditions set forth in this Agreement. The shares of Common Stock sold hereunder at the Closing (as defined below) shall be referred to as the “Shares,” the shares of Common Stock issuable upon exercise of or otherwise pursuant to the Pre-Funded Warrants shall be referred to as the “Warrant Shares” and the Shares and the Pre-Funded Warrants (including, as applicable, the Warrant Shares issuable in exchange therefore) shall be collectively referred to as the “Securities”).

SECTION 2.    Sale and Purchase of the Securities.

2.01    Upon the terms and subject to the conditions herein contained, the Company agrees to sell and issue to each Purchaser, and each Purchaser agrees, severally and not jointly, to purchase from the Company, at a closing to take place remotely via exchange of executed documents (the “Closing” and the date of the Closing, the “Closing Date”) to occur immediately prior to the Effective Time (as such term is defined in the Merger Agreement), that number of Shares (the “Closing Shares”) set forth opposite such Purchaser’s name on the Schedule of Purchasers for the aggregate Purchase Price set forth under the heading “Subscription Amount;” provided, however, for any Purchaser that has provided notice to the Company at least ten (10) Business Days prior to the Closing that such Purchaser would beneficially own (when aggregated with all Securities then beneficially owned by the Purchaser and its affiliates (as calculated pursuant to Section 13(d) of the Exchange Act and Rule 13d-3 promulgated thereunder)) in excess of the Beneficial Ownership Limitation, or as such Purchaser may otherwise choose, in lieu of purchasing Shares such Purchaser may elect to purchase that number of Pre-Funded Warrants set forth opposite such Purchaser’s name on the Schedule of Purchasers in lieu of Shares in such manner to result in the same Subscription Amount being paid by such Purchaser. The “Beneficial Ownership Limitation” shall be 9.9999% of the number of shares of the Common Stock outstanding immediately after giving effect to the issuance of the Securities on the Closing Date.

Exhibit C – Page 1

2.02    At or prior to the Closing, each Purchaser will pay the subscription amount set forth opposite such Purchaser’s name on the Schedule of Purchasers (the “Subscription Amount”) by wire transfer of immediately available funds in accordance with wire instructions provided by the Company to the Purchasers at least two Business Days prior to the Closing (the “Wire Instructions Notice”). If so requested by the Company in the Wire Instructions Notice and agreed by the applicable Purchaser, the Subscription Amount of each Purchaser shall be paid into an escrow fund or trust account designated by the Company in writing (the “Escrow Account”) to be released to the Company only upon satisfaction of each of the closing conditions set forth in Section 6 below. In the event the Closing does not occur within three Business Days of the Closing Date specified in the Wire Instructions Notice, unless otherwise agreed by the Company and such Purchaser, the Company shall, or shall cause the escrow agent for the Escrow Account to, promptly (but not later than two Business Days thereafter) return the aggregate Purchase Price to each Purchaser by wire transfer of U.S. dollars in immediately available funds to the account specified by such Purchaser. On the Closing Date, the Company will deliver, against payment by each Purchaser of its Subscription Amount, the Closing Shares in book-entry form, and shall provide evidence of such issuance from the Company’s transfer agent as of the Closing Date to each Purchaser; provided that, as applicable with respect to any Pre-Funded Warrants, the Company shall deliver to each applicable Purchaser one or more Pre-Funded Warrants (if applicable), in physical form (.pdf being sufficient), free and clear of all restrictive and other legends (except as expressly provided in Article 7 hereof), evidencing the number of Pre-Funded Warrants set forth opposite such Purchaser’s name on the Schedule of Purchasers within three (3) Trading Days after the Closing. Notwithstanding anything to the contrary in this Agreement, (i) each Purchaser acknowledges that, as may be agreed among the Company and one or more Purchasers, such Purchasers may not be required to fund their respective Subscription Amounts until such Purchasers receive evidence of the issuance of the Closing Shares and, if applicable, Pre-Funded Warrants on and as of the Closing Date and (ii) the Schedule of Purchasers may be amended by the Company and the affected Purchaser up to three (3) Business Days prior to the Closing, without the consent of the other parties hereto, to reflect the actual number of Shares and Pre-Funded Warrants purchased by each Purchaser at the Closing, provided that the Company shall provide to Purchasers such updated Schedule of Purchasers.

2.03    Notwithstanding the foregoing, for any Purchaser that has provided notice to the Company that this Section 2.03 shall apply to it, the Company shall not issue or sell, and the Purchaser shall not purchase or acquire, any Securities under this Agreement which, when aggregated with all Securities then beneficially owned by the Purchaser and its affiliates (as calculated pursuant to Section 13(d) of the Exchange Act and Rule 13d-3 promulgated thereunder), would result in the beneficial ownership by the Purchaser of more than 14.9999% of the outstanding shares of Magenta Common Stock immediately after giving effect to the Closing and the consummation of the transactions contemplated by the Merger Agreement, and such Purchaser’s Subscription Amount shall be reduced accordingly.

SECTION 3.    Representations and Warranties of the Purchasers. Each Purchaser, severally and not jointly, represents and warrants to the Company that:

3.01    Validity. The execution, delivery and performance of this Agreement and the consummation by the Purchaser of the transactions contemplated hereby have been duly authorized by all necessary corporate, partnership, limited liability or similar actions, as applicable, on the part of such Purchaser. This Agreement has been duly executed and delivered by the Purchaser and, assuming that this Agreement constitutes the valid and binding obligation of the Company, constitutes a valid and binding obligation of the Purchaser, enforceable against it in accordance with its terms, except as limited by applicable bankruptcy, insolvency, reorganization, moratorium, fraudulent conveyance, and any other laws of general application affecting enforcement of creditors’ rights generally, and as limited by laws relating to the availability of specific performance, injunctive relief, or other equitable remedies.

3.02    Brokers. There is no broker, investment banker, financial advisor, finder or other person which has been retained by the Purchaser who is entitled to any fee or commission for which the Company will be liable in connection with the execution of this Agreement and the consummation of the transactions contemplated hereby.

Exhibit C – Page 2

3.03    Investment Representations and Warranties. The Purchaser understands and agrees that the offering and sale of the Securities has not been registered under the 1933 Act or any applicable state securities laws and is being made in reliance upon federal and state exemptions for transactions not involving a public offering which depend upon, among other things, the bona fide nature of the investment intent and the accuracy of the Purchaser’s representations as expressed herein.

3.04    Acquisition for Own Account. The Purchaser is acquiring the Securities for its own account for investment and not with a view towards distribution in a manner which would violate the 1933 Act or any applicable state or other securities laws. The Purchaser has not been formed for the specific purpose of acquiring the Securities.

3.05    No General Solicitation. The Purchaser is not purchasing the Securities as a result of any advertisement, article, notice or other communication regarding the Securities published in any newspaper, magazine or similar media or broadcast over television, radio or the internet or presented at any seminar or any other general solicitation or general advertisement. The purchase of the Securities by the Purchaser has not been solicited by or through anyone other than the Company or, on the Company’s behalf, Jefferies LLC, Evercore Group L.L.C., Guggenheim Securities, LLC or Raymond James & Associates, Inc. (together, the “Placement Agents”), who have been engaged as joint placement agents for the offering of the Securities.

3.06    Ability to Protect Its Own Interests and Bear Economic Risks. The Purchaser is a sophisticated institutional investor, has the capacity to protect its own interests in connection with the transactions contemplated by this Agreement, and has sufficient knowledge and experience in investing in investments similar to the Securities to properly evaluate the merits and risks of the investment in the Securities. The Purchaser is able to bear the substantial risks of an investment in the Securities including but not limited to loss of the Purchaser’s entire investment therein.

3.07    Accredited Investor. The Purchaser is an “accredited investor” within the meaning of Rule 501(a) (1), (2), (3) or (7) under the 1933 Act.

3.08    Restricted Securities. The Purchaser understands that the Securities will be characterized as “restricted securities” under the federal securities laws inasmuch as they are being acquired from the Company in a private placement under Section 4(a)(2) of the 1933 Act and that, under such laws and applicable regulations, such Securities may be resold without registration under the 1933 Act only in certain limited circumstances.

3.09    Review and Advisors. The Purchaser has had the opportunity to review with the Purchaser’s own tax advisors the federal, state and local tax consequences of its purchase of the Securities set forth opposite such Purchaser’s name on the Schedule of Purchasers and the transactions contemplated by this Agreement. The Purchaser is relying solely on the Purchaser’s own determination as to tax consequences, and on the Purchaser’s own sources of information and advisors with respect to all tax matters, and not on any statements or representations of the Company (other than the representations and warranties in this Agreement), the Placement Agents or any of their respective agents, and understands that the Purchaser (and not the Company) shall be responsible for the Purchaser’s own tax liability that may arise as a result of the transactions contemplated by this Agreement. Based on such information as the Purchaser deemed appropriate and without reliance upon the Placement Agents, the Purchaser has independently made its own analysis and decision to purchase the Securities. The Purchaser has (i) had the opportunity to ask questions of and receive answers directly with respect to its purchase of Securities, and (ii) conducted and completed its own independent due diligence with respect to the purchase of Securities.

3.10    Residency. Such Purchaser’s residence (if an individual) or offices in which its investment decision with respect to the Securities was made (if an entity) are located at the address immediately below such Purchaser’s name on the Schedule of Purchasers, or as otherwise noted on the Schedule of Purchasers.

3.11    Disclosure of Information. The Purchaser has had an opportunity to discuss the Company’s business, management, financial affairs and the terms and conditions of the offering of the Securities and the terms of the Merger with the Company’s management. The foregoing, however, does not limit or modify the representations and warranties of the Company in Section 4 of this Agreement or the right of the Purchasers to rely thereon.

Exhibit C – Page 3

SECTION 4.    Representations and Warranties by the Company. The Company represents and warrants to the Purchasers that:

4.01    Absence of Changes. The Company has conducted its business only in the ordinary course of business (except for the execution and performance of this Agreement and the Merger Agreement, and the discussions, negotiations, and transactions related thereto) and (i) there has not been any change, condition, event, circumstance, occurrence, result, state of facts or development that has or would reasonably be expected to have a materially adverse effect on the business, financial condition, assets, operations, results of operations, stockholders’ equity or financial performance of the Company and its subsidiaries, taken as a whole (a “Material Adverse Effect”), (ii) there have been no transactions entered into by the Company or any of its subsidiaries, other than those in the ordinary course of business and except as contemplated in this Agreement and the Merger Agreement, which are material with respect to the Company and its subsidiaries considered as one enterprise, and (iii) there has been no dividend or distribution of any kind declared, paid or made by the Company on any class of its capital stock.

4.02    Organization and Good Standing of the Company. The Company is a corporation duly incorporated and is validly existing and in good standing under the laws of the State of Delaware, and has all necessary power and authority (i) to conduct its business in all material respects in the manner in which its business is currently being conducted, (ii) to own or lease and use its property and assets in the manner in which its property and assets are currently owned or leased and used in all material respects and (iii) to perform its obligations under all contracts by which it is bound in all material respects. The Company is duly qualified as a foreign corporation to transact business and is in good standing in each other jurisdiction in which such qualification is required, whether by ownership or leasing of property or the conduct of business, except where the failure so to qualify or to be in good standing would not result in a Material Adverse Effect.

4.03    Subsidiaries. The Company does not have any subsidiaries and, except as set forth on Schedule 4.03, does not otherwise own any shares of capital stock or any interest in any other Person. The Company does not control directly or indirectly or have any direct or indirect equity participation or similar interest in any corporation, partnership, limited liability company, joint venture, trust or other business association or entity, except as set forth on Schedule 4.03.

4.04    Validity; Valid Issuance of Securities. The Company has all requisite corporate power and authority to enter into this Agreement and to consummate the transactions contemplated by this Agreement, subject only to the adoption of the Merger Agreement in accordance with the terms thereof by the Company’s stockholders under the Delaware General Corporation Law and the Company’s certificate of incorporation. The execution and delivery of this Agreement and the consummation of the transactions contemplated by this Agreement by the Company have been duly authorized by all necessary corporate action on the part of the Company. Assuming the due authorization, execution and delivery by Purchaser, this Agreement constitutes a legal, valid and binding obligation of the Company, enforceable against the Company in accordance with its terms, except as limited by applicable bankruptcy, insolvency, reorganization, moratorium, fraudulent conveyance, and any other laws of general application affecting enforcement of creditors’ rights generally, and as limited by laws relating to the availability of specific performance, injunctive relief, or other equitable remedies. The Securities are duly authorized and, when issued, sold and delivered in accordance with the terms and for the consideration set forth in this Agreement, will be validly issued, fully paid and nonassessable and free and clear of any liens or other restrictions, other than restrictions on transfer under applicable state and federal securities or such restrictions as the Purchaser has agreed to in writing with the Company, and will not have been issued in violation of or subject to any preemptive or similar rights created under the Company’s certificate of incorporation or bylaws or the Delaware General Corporation Law.

4.05    Governmental Consents and Filings. Assuming the accuracy of the representations made by the Purchasers in Section 3 hereof and except as set forth in the Merger Agreement, no material consent, approval, order or authorization of, or registration, qualification, designation, declaration or filing with, any Governmental Entity (as defined below) is required on the part of the Company in connection with the consummation of the transactions contemplated by this Agreement, except for filings pursuant to Regulation D of the 1933 Act and applicable state securities laws, which have been made or will be made in a timely manner.

Exhibit C – Page 4

4.06    Absence of Violations, Defaults and Conflicts. Neither the Company nor any of its subsidiaries is (i) in violation of its charter, bylaws or similar organizational document, (ii) in default in the performance or observance of any obligation, agreement, covenant or condition contained in any contract, indenture, mortgage, deed of trust, loan or credit agreement, note, lease or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which it or any of them may be bound or to which any of the properties or assets of the Company or any subsidiary is subject (collectively, “Agreements and Instruments”), except for such defaults that would not, singly or in the aggregate, result in a Material Adverse Effect, or (iii) in violation of any law, statute, rule, regulation, judgment, order, writ or decree of any arbitrator, court, governmental body, regulatory body, administrative agency or other authority, body or agency having jurisdiction over the Company or any of its subsidiaries or any of their respective properties, assets or operations (each, a “Governmental Entity”), except for such violations that would not, singly or in the aggregate, result in a Material Adverse Effect. The execution, delivery and the performance of this Agreement and the consummation of the transactions contemplated herein (including the issuance and sale of the Securities) and compliance by the Company with its obligations hereunder do not and will not, whether with or without the giving of notice or passage of time or both, (1) conflict with or constitute a breach of, or default under, or result in the creation or imposition of any lien, charge or encumbrance upon any properties or assets of the Company or any subsidiary pursuant to, the Agreements and Instruments, (2) result in any violation of the provisions of the certificate of incorporation, by-laws or similar organizational document of the Company or any of its subsidiaries or (3) result in any violation of any applicable law, statute, rule, regulation, judgment, order, writ or decree of any Governmental Entity, except in the case of clauses (1) and (3), for such violations as would not, singly or in the aggregate, have or reasonably be expected to have a Material Adverse Effect, or materially affect the validity of the Securities or the legal authority of the Company to perform its obligations hereunder and timely comply in all material respects with the terms of this Agreement or the Merger Agreement.

4.07    Absence of Proceedings. There is no action, suit, proceeding or, to the knowledge of the Company, inquiry or investigation, before or brought by any Governmental Entity now pending or, to the knowledge of the Company, threatened, against or affecting the Company or any of its subsidiaries, which would have or reasonably be expected to have a Material Adverse Effect or materially affect the validity of the Securities or the legal authority of the Company to perform its obligations hereunder and timely comply in all material respects with the terms of this Agreement or the Merger Agreement.

4.08    Possession of Licenses and Permits. The Company and its subsidiaries possess such permits, licenses, approvals, consents and other authorizations (collectively, “Governmental Licenses”) issued by the appropriate Governmental Entities necessary to conduct the business now operated by them, except where the failure so to possess would not, singly or in the aggregate, have or reasonably be expected to have a Material Adverse Effect. The Company and its subsidiaries are in compliance with the terms and conditions of all Governmental Licenses, except where the failure so to comply would not, singly or in the aggregate, have or reasonably be expected to have a Material Adverse Effect. All of the Governmental Licenses are valid and in full force and effect, except when the invalidity of such Governmental Licenses or the failure of such Governmental Licenses to be in full force and effect would not, singly or in the aggregate, have or reasonably be expected to have a Material Adverse Effect. Neither the Company nor any of its subsidiaries has received any notice of proceedings relating to the revocation or modification of any Governmental Licenses which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would have or reasonably be expected to have a Material Adverse Effect.

4.09    Payment of Taxes. All United States federal income tax returns of the Company and its subsidiaries required by law to be filed have been filed and all taxes shown by such returns or otherwise assessed, which are due and payable, have been paid, except assessments against which appeals have been or will be promptly taken and as to which adequate reserves have been provided. No assessment in connection with United States federal tax returns has been made against the Company. The Company and its subsidiaries have filed all other tax returns that are required to have been filed by them through the date hereof or have timely requested extensions thereof pursuant to applicable foreign state, local or other law except insofar as the failure to file such returns would not have or reasonably be expected to have a Material Adverse Effect, and has paid all taxes due pursuant to such returns or all taxes due and payable pursuant to any assessment received by the Company and its subsidiaries, except for such taxes, if any, as are being contested in good faith and as to which adequate reserves have been established by the Company or its subsidiaries and except where the failure to pay such taxes would not have or reasonably be expected to have a Material Adverse Effect.

Exhibit C – Page 5

4.10    Insurance. The Company and the subsidiaries carry or are entitled to the benefits of insurance, with what the Company reasonably believes to be financially sound and reputable insurers, in such amounts and covering such risks as is adequate for the conduct of their respective businesses and the value of their respective properties and assets, and all such insurance is in full force and effect. The Company has no reason to believe that it or any of the subsidiaries will not be able (i) to renew its existing insurance coverage as and when such policies expire or (ii) to obtain comparable coverage from similar institutions as may be necessary or appropriate to conduct its business as now conducted and at a cost that would not have or reasonably be expected to have a Material Adverse Effect.

4.11    Investment Company Act. The Company is not required, and upon the issuance and sale of the Securities will not be required, to register as an “investment company” under the Investment Company Act of 1940, as amended.

4.12    Shell Company Status. Neither the Company nor Magenta is, or has ever been, an issuer identified in Rule 144(i)(1) promulgated under the Securities Act.

4.13    Regulatory Matters. Except as would not, singly or in the aggregate, have or reasonably be expected to have a Material Adverse Effect: (i) neither the Company nor any of its subsidiaries has received any FDA Form 483, notice of adverse finding, warning letter or other correspondence or written notice from the U.S. Food and Drug Administration (“FDA”) or any other Governmental Entity alleging or asserting noncompliance with any Applicable Laws (as defined in clause (ii) below) or Authorizations (as defined in clause (iii) below); (ii) the Company and each of its subsidiaries is and has been in compliance with statutes, laws, ordinances, rules and regulations applicable to the Company and its subsidiaries for the ownership, testing, development, manufacture, packaging, processing, use, distribution, marketing, labeling, promotion, sale, offer for sale, storage, import, export or disposal of any product manufactured or distributed by the Company, including without limitation, the Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 301, et seq., similar laws of other Governmental Entities and the regulations promulgated pursuant to such laws (collectively, “Applicable Laws”); (iii) the Company and each of its subsidiaries possesses all licenses, certificates, approvals, clearances, authorizations, permits and supplements or amendments thereto required by any such Applicable Laws and/or to carry on its businesses as now conducted (“Authorizations”) and such Authorizations are valid and in full force and effect and the Company is not in violation of any term of any such Authorizations; (iv) neither the Company nor any of its subsidiaries has received notice of any ongoing claim, action, suit, proceeding, hearing, enforcement, investigation, arbitration or other action from any Governmental Entity or third party alleging that any product, operation or activity is in violation of any Applicable Laws or Authorizations or has any knowledge that any such Governmental Entity or third party is considering any such claim, litigation, arbitration, action, suit, investigation or proceeding, nor, to the Company’s knowledge, has there been any noncompliance with or violation of any Applicable Laws by the Company or any of its subsidiaries that could reasonably be expected to require the issuance of any such communication or result in an investigation, corrective action, or enforcement action by FDA or similar Governmental Entity; (v) neither the Company nor any of its subsidiaries has received notice that any Governmental Entity has taken, is taking or intends to take action to limit, suspend, modify or revoke any Authorizations or has any knowledge that any such Governmental Entity is threatening or is considering such action; and (vi) the Company and each of its subsidiaries has filed, obtained, maintained or submitted all reports, documents, forms, notices, applications, records, claims, submissions and supplements or amendments as required by any Applicable Laws or Authorizations and that all such reports, documents, forms, notices, applications, records, claims, submissions and supplements or amendments were complete, correct and not misleading on the date filed (or were corrected or supplemented by a subsequent submission).

4.14    Compliance With Laws. The Company has complied in all material respects with, is not in material violation of, and has not received any written notice alleging any violation with respect to, any applicable provisions of any statute, law or regulation with respect to the conduct of its business, or the ownership or operation of its properties or assets.

Exhibit C – Page 6

4.15    Financial Statements. The Company has made available to each Purchaser its unaudited balance sheets as of December 31, 2022, together with related unaudited statements of operations, changes in stockholders’ equity and cash flows, and notes thereto, of the Company for the fiscal year then ended (collectively, the “Financial Statements”). The Financial Statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”) applied on a consistent basis throughout the periods indicated, except that the unaudited Financial Statements may not contain all footnotes and other presentation items required by GAAP and are subject to normal and recurring year-end adjustments that are not reasonably expected to be material in amount. The Financial Statements fairly present in all material respects the financial condition and operating results of the Company as of the dates, and for the periods, indicated therein, subject in the case of the unaudited Financial Statements to normal year-end audit adjustments. Except as set forth in the Financial Statements, between December 31, 2022 and the date of this Agreement, the Company has not incurred any material liabilities or obligations, contingent or otherwise, other than (a) liabilities incurred in the ordinary course of business; (b) obligations under contracts and commitments incurred in the ordinary course of business; (c) liabilities for transaction expenses incurred in connection with the transactions contemplated by this Agreement and the Merger Agreement; and (d) liabilities and obligations of a type or nature not required under GAAP to be reflected in the Financial Statements. The Company maintains and will continue to maintain a standard system of accounting established and administered to provide reasonable assurance that transactions are recorded as necessary to permit preparation of the financial statements of the Company in conformity with GAAP.

4.16    Information Provided. The information to be supplied by or on behalf of the Company for inclusion or incorporation by reference in the Registration Statement (as defined in the Merger Agreement), or supplied by or on behalf of the Company for inclusion in any filing pursuant to Rule 165 and Rule 425 under the Securities Act or Rule 14a-12 under the 1934 Act (each a “Regulation M-A Filing”), shall not, at the time the Registration Statement or any such Regulation M-A Filing is filed with the Securities and Exchange Commission (the “Commission”), at any time it is amended or supplemented or at the time the Registration Statement is declared effective by the Commission, as applicable, contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein not misleading. The information to be supplied by or on behalf of the Company for inclusion in the Registration Statement to be sent to the stockholders of Magenta in connection with the meeting of Magenta’s stockholders (the “Public Company Meeting”), shall not, on the date the proxy statement/prospectus included in the Registration Statement is first mailed to stockholders of Magenta, at the time of the Public Company Meeting or at the Effective Time, contain any statement that, at such time and in light of the circumstances under which it shall be made, is false or misleading with respect to any material fact, or omit to state any material fact necessary in order to make the statements made in the Registration Statement not false or misleading; or omit to state any material fact necessary to correct any statement in any earlier communication with respect to the solicitation of proxies for the Public Company Meeting that has become false or misleading.

4.17    No Additional Agreements. The Company does not have any agreement with any Purchaser with respect to the transactions contemplated by this Agreement other than as specified in this Agreement.

4.18    Private Placement. None of the Company, its subsidiaries or any person acting on its or their behalf, has, directly or indirectly, made any offers or sales of any security or solicited any offers to buy any security under any circumstances that would require registration under the 1933 Act of the Securities being sold pursuant to this Agreement. Assuming the accuracy of the representations and warranties of the Purchasers contained in Section 3 hereof, the issuance and sale of the Securities is exempt from registration under the 1933 Act.

4.19    No Disqualification Events. No “bad actor” disqualifying event described in Rule 506(d)(1)(i)-(viii) of the 1933 Act (a “Disqualification Event”) is applicable to the Company or, to the Company’s knowledge, any Company Covered Person (as defined below), except for a Disqualification Event as to which Rule 506(d)(2)(ii–iv) or (d)(3) is applicable. “Company Covered Person” means, with respect to the Company as an “issuer” for purposes of Rule 506 promulgated under the 1933 Act, any person listed in the first paragraph of Rule 506(d)(1). The Company is not aware of any Person (other than any Company Covered Person) that has been or will be paid (directly or indirectly) remuneration for solicitation of purchasers in connection with the sale of the Securities pursuant to this Agreement. The Company has complied, to the extent applicable, with its disclosure obligations under Rule 506(e).

Exhibit C – Page 7

4.20    No General Solicitation. Neither the Company nor, to the Company’s knowledge, any person acting on behalf of the Company has offered or sold any of the Securities by any form of general solicitation or general advertising.

4.21    No Integrated Offering. Assuming the accuracy of the Purchasers’ representations and warranties set forth in Section 3 hereof, none of the Company, its subsidiaries or, to the Company’s knowledge, any of its or their Affiliates or any Person acting on its or their behalf has, directly or indirectly, at any time within the past six months, made any offers or sales of any Company security or solicited any offers to buy any security under circumstances that would (i) eliminate the availability of the exemption from registration under Regulation D under the 1933 Act in connection with the offer and sale by the Company of the Securities as contemplated hereby or (ii) cause the offering of the Securities pursuant to this Agreement to be integrated with prior offerings by the Company for purposes of any applicable law, regulation or stockholder approval provisions, including, without limitation, under the rules and regulations of any National Exchange on which any of the securities of the Company are listed or designated.

4.22    Brokers. Other than the Placement Agents, there is no broker, investment banker, financial advisor, finder or other person which has been retained by or is authorized to act on behalf of the Company that is entitled to any fee or commission in connection with the execution of this Agreement and the consummation of the transactions contemplated hereby.

4.23    Additional Representations and Warranties. The Company’s representations and warranties set forth in the Merger Agreement in Section 3.6 (Capitalization), 3.10 (Title to Assets), 3.11 (Real Property; Leasehold), 3.12 (Intellectual Property), 3.13 (Agreements, Contracts and Commitments), 3.17 (Employee and Labor Matters; Benefit Plans), 3.18 (Environmental Matters), 3.21(Transactions with Affiliates) and 3.22 (Privacy and Data Security) are hereby incorporated by reference and made by the Company, as qualified by the disclosures in the Company Disclosure Schedule (as defined in the Merger Agreement). As of the Effective Date, to the knowledge of the Company, the representations and warranties of Magenta in the Merger Agreement and in any certificate or other writing delivered by Magenta pursuant thereto are true and correct.

4.24    Reliance by Purchasers. The Company acknowledges that each Purchaser will rely upon the truth and accuracy of, and the Company’s compliance with, the representations, warranties, agreements, acknowledgements and understandings of the Company set forth in this Agreement.

SECTION 5.    Covenants.

5.01    Further Assurances. At or prior to Closing, each party agrees to cooperate and generally do such reasonable acts and things in good faith as may be necessary to timely satisfy each of the conditions to be satisfied by it as provided in Section 6 of this Agreement and effectuate the intents and purposes of this Agreement subject to the terms and conditions hereof.

5.02    Disclosure of Transactions and Other Material Information. The Company shall or shall cause Magenta to, on or before 9:00 a.m., New York City time, on the Business Day immediately following the date of this Agreement (or if this Agreement is executed between midnight and 9:00 a.m., New York City time, on any Business Day, no later than 9:01 a.m. on the date the Agreement is executed), issue one or more press releases and/or file with the Commission a Current Report on Form 8-K (collectively, the “Disclosure Document”) disclosing all material terms of the transactions contemplated hereby and any other material nonpublic information that the Company, Magenta or their respective officers, directors, employees, agents or any other person acting at the direction of the Company or Magenta has provided to the Purchasers in connection with the transactions contemplated by this Agreement prior to the filing of the Disclosure Document. The Company represents and warrants that, from and after the issuance of the Disclosure Document, no Purchaser shall be in possession of any material, nonpublic information received from the Company, Magenta or their respective officers, directors, employees, agents or other person acting at their direction. The Company shall not, and shall cause its officers, directors, employees and agents and Magenta not to, publicly disclose the name of any Purchaser or any affiliate or investment adviser of any Purchaser, or include the name of any Purchaser or any affiliate or investment adviser of any Purchaser without the prior written consent (including by e-mail) of such Purchaser (i) in any press release or marketing materials, or (ii) in any filing with the Commission or any regulatory agency or trading market, except

Exhibit C – Page 8

(A) as required by the federal securities laws, rules or regulations, (B) to the extent such disclosure is required by other laws, rules or regulations, at the request of the staff of the Commission or regulatory agency or under regulations of any national securities exchange on which Magenta’s securities are listed for trading or (C) to the extent such disclosure contains only information previously approved in accordance with this Section 5.02, and in the case of any disclosure made pursuant to clause (ii), the Company will provide the Purchaser with prior written notice (including by e-mail) of and an opportunity to review the applicable portion of such filing.

5.03    Expenses. The Company and each Purchaser is liable for, and will pay, its own expenses incurred in connection with the negotiation, preparation, execution and delivery of this Agreement, including, without limitation, attorneys’ and consultants’ fees and expenses.

5.04    Form S-4. On or prior to the Closing Date, the Registration Statement will register the issuance of the shares of Magenta Common Stock (as defined in the Merger Agreement) to be issued, subject to and in accordance with the terms of the Merger Agreement, by virtue of the Contemplated Transactions (as defined in the Merger Agreement).

5.05    Blue Sky Laws. The Company, on or before the Closing Date, shall take such action as the Company shall reasonably determine is necessary in order to obtain an exemption for or to qualify the Securities for sale to each Purchaser at the Closing pursuant to this Agreement under applicable securities or “blue sky” laws of the states of the United States (or to obtain an exemption from such qualification). The Company shall make all filings and reports relating to the offer and sale of the Securities required under applicable securities or “blue sky” laws of the states of the United States following the Closing Date.

5.06    No Amendment or Waiver of Merger Agreement Terms. The Company shall not amend, modify or waive (or approve an amendment, modification or a waiver requested by Magenta of, or fail to contest an action regarding a breach of) any provision of the Merger Agreement in a manner that would reasonably be expected to materially and adversely affect the benefits that the Purchaser would reasonably expect to receive pursuant to this Agreement without the consent of each Purchaser.

5.07    Equal Treatment of Purchasers. No consideration shall be offered or paid to any Purchaser to amend or consent to a waiver or modification of any provision of this Agreement unless the same consideration is also offered to all of the Purchasers. For clarification purposes, this provision constitutes a separate right granted to each Purchaser by the Company and negotiated separately by each Purchaser and shall not in any way be construed as the Purchasers acting in concert or as a group with respect to the purchase, disposition or voting of shares of Common Stock or otherwise.

5.08    Legend Removal. The restrictive legends described in Section 7.01 shall promptly be removed in accordance with applicable securities laws following the closing of the Merger. The shares of Magenta Common Stock to be received in the Merger in exchange for the Shares and the Warrant Shares will be issued in book-entry form, free and clear of any liens or other restrictions whatsoever and without restrictive legends in accordance with applicable securities laws.

SECTION 6.    Conditions of Closing.

6.01    Conditions of the Purchasers’ Obligations at the Closing. The obligations of each Purchaser under Section 2 hereof are subject to the fulfillment, at or prior to the Closing, of all of the following conditions, unless otherwise waived by such Purchaser solely as to itself.

(a)    Representations and Warranties. The representations and warranties of the Company contained in this Agreement shall be true and correct in all respects on the Effective Date, and shall be true and correct in all material respects on and as of the Closing Date with the same effect as though such representations and warranties had been made on and as of the Closing Date (except (i) to the extent expressly made as of an earlier date in which case as of such earlier date and (ii) representations and warranties that are qualified as to materiality or Material Adverse Effect, which representations and warranties shall be true in all respects).

Exhibit C – Page 9

(b)    Performance. The Company shall have performed and complied in all material respects with all covenants, agreements, obligations and conditions contained in this Agreement that are required to be performed or complied with by it on or prior to the Closing Date.

(c)    Compliance Certificate. The Chief Executive Officer of the Company shall have delivered to the Purchasers at the Closing Date a certificate, in form and substance reasonably acceptable to the Purchasers, certifying that the conditions specified in Sections 6.01(a), 6.01(b), 6.01(f), 6.01(j), 6.01(k) and 6.01(l) of this Agreement have been fulfilled.

(d)    Qualification under Securities Laws. All registrations, qualifications, permits and approvals, if any, required under applicable securities laws shall have been obtained for the lawful execution, delivery and performance of this Agreement.

(e)    Secretary’s Certificate. The Secretary of the Company shall have delivered to the Purchasers at the Closing a certificate, in form and substance reasonably acceptable to the Purchasers (such consent not to be unreasonably withheld, conditioned or delayed), certifying (i) the certificate of incorporation and bylaws of the Company, (ii) authorization of the Board of Directors of the Company approving this Agreement and the transactions contemplated under this Agreement (including the Merger Agreement) and (iii) as to certificates evidencing the good standing of the Company in Delaware issued by the Secretary of State of Delaware and in the Commonwealth of Massachusetts issued by the Secretary of the Commonwealth of Massachusetts, each as of a date within five Business Days of the Closing Date.

(f)    Merger. All conditions to the closing of the Merger shall have been satisfied or waived (other than the Closing hereunder and other than those conditions which, by their nature, are to be satisfied at the closing of the transactions contemplated by the Merger Agreement), and the closing of the Merger shall be set to occur substantially concurrently with the Closing hereunder. The Company shall not have amended, modified, or waived any provision under the Merger Agreement in a manner that would reasonably be expected to materially and adversely affect the benefits that Purchaser would reasonably expect to receive under this Agreement without having received each affected Purchaser’s prior written consent.

(g)    No Injunction. No statute, rule, regulation, executive order, decree, ruling or injunction shall have been enacted, entered, promulgated or endorsed by any Governmental Entity of competent jurisdiction that prohibits the consummation of any of the transactions contemplated by this Agreement.

(h)    Registration Rights Agreement. The Company shall have delivered the fully executed Registration Rights Agreement.

(i)    Opinion of Company Counsel. The Purchasers shall have received from Gibson, Dunn & Crutcher LLP, counsel for the Company, an opinion, dated as of the Closing, in the form agreed between the Company and the Purchaser Majority.

(j)    Registration Statement; Proxy Statement/Prospectus. The Registration Statement shall have become effective under the 1933 Act and no stop order suspending the effectiveness of the Registration Statement shall have been issued and no proceeding for that purpose, and no similar proceeding with respect to the Registration Statement shall have been initiated or threatened in writing by the Commission or its staff.

(k)    Nasdaq. Magenta shall have received approval from The Nasdaq Stock Market that the shares of Magenta Common Stock to be issued in the Contemplated Transactions shall have been approved for listing (subject to official notice of issuance) on Nasdaq.

(l)    Financing Amount. The Company shall receive at Closing the Financing Amount.

Exhibit C – Page 10

6.02    Conditions of the Company’s Obligations. The obligations of the Company under Section 2 hereof are subject to the fulfillment, at or prior to the Closing, of all of the following conditions, any of which may be waived in whole or in part by the Company in its absolute discretion.

(a)    Representations and Warranties. The representations and warranties of the Purchasers contained in this Agreement shall be true and correct as of the Effective Date and true and correct in all material respects on and as of the Closing Date with the same effect as though such representations and warranties had been made on and as of the Closing Date (except to the extent expressly made as of an earlier date in which case shall be as of such earlier date).

(b)    Performance. Each Purchaser shall have performed and complied with all covenants, agreements, obligations and conditions contained in this Agreement that are required to be performed or complied with by it on or prior to the Closing Date.

(c)    Qualification under Securities Laws. All registrations, qualifications, permits and approvals, if any, required under applicable securities laws shall have been obtained for the lawful execution, delivery and performance of this Agreement.

(d)    Merger. All conditions to the closing of the Merger shall have been satisfied or waived (other than the Closing hereunder and other than those conditions which, by their nature, are to be satisfied at the closing of the transactions contemplated by the Merger Agreement), and the closing of the Merger shall be set to occur substantially concurrently with the Closing hereunder.

SECTION 7.    Transfer Restrictions; Restrictive Legend.

7.01    Transfer Restrictions. Each Purchaser understands that the Company may, as a condition to the transfer of any of the Securities, require that the request for transfer be accompanied by a certificate and/or an opinion of counsel reasonably satisfactory to the Company, to the effect that the proposed transfer does not result in a violation of the 1933 Act, unless such transfer is covered by an effective registration statement or is exempt from the registration requirements of the 1933 Act, including under Rule 144. It is understood that the certificates evidencing the Securities may bear substantially the following legend:

“THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY APPLICABLE STATE SECURITIES LAWS. THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF A REGISTRATION STATEMENT IN EFFECT WITH RESPECT TO THE SECURITIES UNDER SUCH ACT OR APPLICABLE STATE SECURITIES LAWS OR A VALID EXEMPTION FROM REGISTRATION UNDER SUCH ACT OR APPLICABLE STATE SECURITIES LAWS.”

SECTION 8.    Definitions. Unless the context otherwise requires, the terms defined in this Section 8 shall have the meanings specified for all purposes of this Agreement.

“1933 Act” means the Securities Act of 1933, as amended.

“1934 Act” means the Securities Exchange Act of 1934, as amended.

“Affiliate” shall have the meaning ascribed to such term in Rule 12b-2 of the General Rules and Regulations under the 1934 Act.

“Business Day” means any day other than Saturday, Sunday or other day on which commercial banks in the City of New York are authorized or required by law to remain closed.

“Financing Amount” means $50,000,000.

Exhibit C – Page 11

“National Exchange” means the Nasdaq Global Select Market, the Nasdaq Global Market, the Nasdaq Capital Market, or the New York Stock Exchange.

“Person” means an individual or corporation, partnership, trust, incorporated or unincorporated association, joint venture, limited liability company, joint stock company, government (or an agency or subdivision thereof) or other entity of any kind.

“Purchase Price” means an amount equal to (i) the Company Equity Value (as defined in the Merger Agreement), (ii) divided by the number of Company Outstanding Shares (as defined in the Merger Agreement but excluding the Securities being issued hereunder) as of immediately prior to the closing of offering of the Securities hereunder.

“Purchaser Majority” means, prior to the Closing, the Purchasers committed to purchase at least a majority the Securities, provided that each Purchaser who has committed to purchase at least $10,000,000 of the Securities is included in such majority and, following the Closing, both (i) the Purchasers who hold at least a majority of the Securities (including any Magenta Common Stock issued in exchange therefore) still held by the Purchasers, and (ii) each Purchaser (A) whose Subscription Amount exceeds $10,000,000 and (B) who continues to hold at least fifty percent (50%) of the Securities (including any Magenta Common Stock issued in exchange therefore) purchased on the Closing Date.

“Registration Rights Agreement” means the Registration Rights Agreement, in the form attached hereto as Exhibit A, to be entered into at the Closing among the Company and each Purchaser.

“Rule 144” means Rule 144 promulgated by the Commission pursuant to the 1933 Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as Rule 144.

SECTION 9.    Miscellaneous.

9.01    Waivers and Amendments. Neither this Agreement, nor any provision hereof, may be changed, waived, amended or modified orally or by course of dealing, but only by an instrument in writing executed by the Company and the Purchaser Majority, provided that, (a) if any, change, waiver, amendment, modification disproportionately and adversely impacts a Purchaser (or group of Purchasers), the consent of such disproportionately impacted Purchaser (or group of Purchasers) shall be required and (b) the consent of each Purchaser shall be required for any change in the Purchase Price or applicable Purchaser’s Subscription Amount, any change in the type of security to be issued to Purchasers at Closing, or the amendment or waiver of Section 9.13 or of any of the closing conditions set forth in Sections 6.01(a), 6.01(j) 6.01(k) or 6.01(l).

9.02    Notices. All notices, requests, consents, and other communications under this Agreement shall be in writing and shall be deemed delivered (a) when delivered, if delivered personally, (b) four Business Days after being sent by registered or certified mail, return receipt requested, postage prepaid, (c) one Business Day after being sent via a reputable nationwide overnight courier service guaranteeing next Business Day delivery, or (d) when receipt is acknowledged, in the case of email, in each case to the intended recipient as set forth below, with respect to the Company, and to the addresses set forth on the Schedule of Purchasers with respect to the Purchasers.

if to the Company:

Dianthus Therapeutics, Inc.

7 Times Square

New York, New York 10036

Attention: Ryan Savitz, Chief Financial Officer

Email:

with a copy to (which shall not constitute notice):

Gibson, Dunn & Crutcher LLP

555 Mission Street, Suite 3000

Exhibit C – Page 12

San Francisco, CA 94105

Attention: Ryan Murr, Brenden Berns, Chris Trester

Email:

or at such other address as the Company or each Purchaser may specify by written notice to the other parties hereto in accordance with this Section 9.02.

9.03    Cumulative Remedies. None of the rights, powers or remedies conferred upon each Purchaser, on the one hand, or the Company, on the other hand, shall be mutually exclusive, and each such right, power or remedy shall be cumulative and in addition to every other right, power or remedy, whether conferred by this Agreement or now or hereafter available at law, in equity, by statute or otherwise.

9.04    Successors and Assigns. All the terms and provisions of this Agreement shall be binding upon and inure to the benefit of and be enforceable by the respective parties hereto, the successors and permitted assigns of each Purchaser and the successors of the Company, whether so expressed or not. None of the Purchasers may assign its rights or obligations hereof without the prior written consent of the Company, except that a Purchaser may, without the prior consent of the Company, assign its rights to purchase the Securities hereunder to any of its affiliates or to any other investment funds or accounts managed or advised by the investment manager who acts on behalf of Purchaser (provided each such assignee agrees to be bound by the terms of this Agreement and makes the same representations and warranties set forth in Section 3 hereof). The Company may not assign its rights or obligations hereof without the consent of the Purchaser Majority. This Agreement shall not inure to the benefit of or be enforceable by any other person.

9.05    Exculpation of Placement Agents. Each party hereto agrees for the express benefit of each of the Placement Agents, its affiliates and its representatives that:

(a)    Each of the Placement Agents is acting solely as financial advisor to the Company in connection with the sale of the Securities and is not acting in any other capacity and is not and shall not be construed as a fiduciary for the Purchaser, or any other person or entity in connection with the sale of Securities.

(b)    No Placement Agent or any of its affiliates or any of its representatives (i) shall be liable for any improper payment made in accordance with the information provided by the Company, (ii) has made or will make any representation or warranty, express or implied, of any kind or character, and has not provided any advice or recommendation to the Purchasers in connection with the purchase or sale of the Securities, (iii) has any responsibilities as to the validity, accuracy, completeness, value or genuineness, as of any date, of any information, certificates or documentation delivered by or on behalf of the Company pursuant to this Agreement, the Registration Rights Agreement or the Merger Agreement, or in connection with any of the transactions contemplated by such agreements, including any valuation, offering or marketing materials, or any omissions from such materials; or (iv) shall be liable or have any obligation (including without limitation, for or with respect to any losses, claims, damages, obligations, penalties, judgments, awards, liabilities, costs, expenses or disbursements incurred by the Purchaser, the Company or any other person or entity), whether in contract, tort or otherwise to the Purchaser or to any person claiming through the Purchaser, (x) for any action taken, suffered or omitted by any of them in good faith and reasonably believed to be authorized or within the discretion or rights or powers conferred upon it by this Agreement, the Registration Rights Agreement or the Merger Agreement, (y) for anything which any of them may do or refrain from doing in connection with this Agreement, the Registration Rights Agreement or the Merger Agreement, except for such party’s own gross negligence, willful misconduct or bad faith, or (z) for anything otherwise in connection with the purchase and sale of the Securities.

(c)    The Placement Agents, their respective affiliates and their respective representatives shall be entitled to rely on, and shall be protected in acting upon, any certificate, instrument, opinion, notice, letter or any other document or security delivered to any of them by or on behalf of the Company.

9.06    Headings. The headings of the Sections and paragraphs of this Agreement have been inserted for convenience of reference only and do not constitute a part of this Agreement.

Exhibit C – Page 13

9.07    Governing Law; Jurisdiction. This Agreement shall be governed by, and construed in accordance with, the laws of the State of Delaware, regardless of the laws that might otherwise govern under applicable principles of conflicts of laws. IN ANY ACTION OR PROCEEDING BETWEEN ANY OF THE PARTIES ARISING OUT OF OR RELATING TO THIS AGREEMENT OR ANY OF THE CONTEMPLATED TRANSACTIONS, EACH OF THE PARTIES: (A) IRREVOCABLY AND UNCONDITIONALLY CONSENTS AND SUBMITS TO THE EXCLUSIVE JURISDICTION AND VENUE OF THE COURT OF CHANCERY OF THE STATE OF DELAWARE OR, TO THE EXTENT SUCH COURT DOES NOT HAVE SUBJECT MATTER JURISDICTION, THE SUPERIOR COURT OF THE STATE OF DELAWARE OR THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF DELAWARE, (B) AGREES THAT ALL CLAIMS IN RESPECT OF SUCH ACTION OR PROCEEDING SHALL BE HEARD AND DETERMINED EXCLUSIVELY IN ACCORDANCE WITH CLAUSE (A) OF THIS SECTION 9.07, (C) WAIVES ANY OBJECTION TO LAYING VENUE IN ANY SUCH ACTION OR PROCEEDING IN SUCH COURTS, (D) WAIVES ANY OBJECTION THAT SUCH COURTS ARE AN INCONVENIENT FORUM OR DO NOT HAVE JURISDICTION OVER ANY PARTY, (E) AGREES THAT SERVICE OF PROCESS UPON SUCH PARTY IN ANY SUCH ACTION OR PROCEEDING SHALL BE EFFECTIVE IF NOTICE IS GIVEN IN ACCORDANCE WITH SECTION 9.02 OF THIS AGREEMENT AND (F) IRREVOCABLY WAIVES THE RIGHT TO TRIAL BY JURY.

9.08    Survival. The representations and warranties of the Company and the Purchasers contained in Sections 3 and 4 and the agreements and covenants set forth in Sections 5 and 9 shall survive the Closing for the applicable statute of limitations (unless such covenant or agreement terminates earlier in accordance with its terms), which shall not be extended by Section 8106(c) of Title 10 of the Delaware Code or any similar law. Each Purchaser shall be responsible only for its own representations, warranties, agreements and covenants hereunder.

9.09    Counterparts; Effectiveness. This Agreement may be executed in any number of counterparts and by different parties hereto in separate counterparts, with the same effect as if all parties had signed the same document. All such counterparts (including counterparts delivered by facsimile or other electronic format) shall be deemed an original, shall be construed together and shall constitute one and the same instrument. This Agreement shall become effective when each party hereto shall have received counterparts hereof signed by all of the other parties hereto.

9.10    Entire Agreement. This Agreement, together with the Registration Rights Agreement, contains the entire agreement among the parties hereto with respect to the subject matter hereof and, except as set forth below, this agreement supersedes and replaces all other prior agreements, written or oral, among the parties hereto with respect to the subject matter hereof. Notwithstanding the foregoing or anything to the contrary in this Agreement and subject to Section 5.02, this Agreement shall not supersede any confidentiality or other non-disclosure agreements that may be in place between the Company and any Purchaser as of the date hereof.

9.11    Severability. If any provision of this Agreement shall be found by any court of competent jurisdiction to be invalid or unenforceable, the parties hereby waive such provision to the extent that it is found to be invalid or unenforceable. Such provision shall, to the maximum extent allowable by law, be modified by such court so that it becomes enforceable, and, as modified, shall be enforced as any other provision hereof, all the other provisions hereof continuing in full force and effect.

9.12    Independent Nature of Purchasers’ Obligations and Rights. The obligations of each Purchaser under this Agreement are several and not joint with the obligations of any other Purchaser, and no Purchaser shall be responsible in any way for the performance of the obligations of any other Purchaser under this Agreement. Nothing contained herein, and no action taken by any Purchaser pursuant hereto, shall be deemed to constitute the Purchasers as, and the Company acknowledges that the Purchasers do not so constitute, a partnership, an association, a joint venture or any other kind of entity, or create a presumption that the Purchasers are in any way acting in concert or as a group, and the Company will not assert any such claim with respect to such obligations or the transactions contemplated by this Agreement, and the Company acknowledges that the Purchasers are not acting in concert or as a group with respect to such obligations or the transactions contemplated by this Agreement. The Company acknowledges and each Purchaser confirms that it has independently participated in the negotiation of the transaction contemplated hereby with the advice of its own counsel and advisors. Each Purchaser shall be entitled to independently protect and enforce its rights, including, without limitation, the rights arising out of this Agreement,

Exhibit C – Page 14

..and it shall not be necessary for any other Purchaser to be joined as an additional party in any proceeding for such purpose. The Company has elected to provide all Purchasers with the same terms for the convenience of the Company and not because it was required or requested to do so by any Purchaser.

9.13    Termination. This Agreement shall terminate and be void and of no further force and effect, and all obligations of the parties hereunder shall terminate without any further liability on the part of any party in respect thereof, upon the earlier to occur of (a) such date and time that the Merger Agreement is terminated in accordance with its terms, (b) upon the mutual written agreement of the Company and the Purchaser, (c) if, on the Closing Date, any of the conditions of Closing set forth in Section 6 have not been satisfied as of the time required hereunder to be so satisfied or waived by the party entitled to grant such waiver and, as a result thereof, the transactions contemplated by this Agreement are not consummated, or (d) if the Closing has not occurred on or before November 2, 2023, other than as a result of a Willful Breach of a Purchaser’s obligations hereunder; provided, however, that nothing herein shall relieve any party to this Agreement of any liability for common law fraud or for any Willful Breach of any representation, warranty, covenant, obligation or other provision contained in this Agreement. “Willful Breach” means a deliberate act or deliberate failure to act, taken with the actual knowledge that such act or failure to act would result in or constitute a material breach of this Agreement.

9.14    No Third-Party Beneficiaries. This Agreement is intended for the benefit of the parties hereto and their respective successors and permitted assigns and is not for the benefit of, nor may any provision hereof be enforced by, any other Person; provided, however, that each of the Placement Agents will be entitled to rely, as an express third-party beneficiary, on the representations and warranties of the Purchasers and the Company set forth in Section 3 and Section 4 hereof, the covenants set forth in Section 5 hereof and Sections 9.04, 9.05, 9.08, 9.12 and 9.13 hereof.

[Signature pages follow]

Exhibit C – Page 15

IN WITNESS WHEREOF, the parties hereto have caused this Subscription Agreement to be duly executed as of the Effective Date.

[Signature Page to Subscription Agreement]

Exhibit C – Page 16

IN WITNESS WHEREOF, the parties hereto have caused this Subscription Agreement to be duly executed as of the Effective Date.

[Signature Page to Subscription Agreement]

Exhibit C – Page 17

Schedule I

SCHEDULE OF PURCHASERS

Exhibit C – Page 18

Exhibit A

Form of Registration Rights Agreement

Exhibit C – Page 19

Exhibit B

Form of Pre-Funded Warrant

Exhibit C – Page 20

Exhibit D

FORM OF CONTINGENT VALUE RIGHTS AGREEMENT

THIS CONTINGENT VALUE RIGHTS AGREEMENT (this “Agreement”), dated as of [__], 2023, is entered into by and among Magenta Therapeutics, Inc., a Delaware corporation (the “Company”) and Computershare Inc., a Delaware corporation (“Computershare”), and its wholly-owned subsidiary, Computershare Trust Company, N.A., a federally chartered trust company (collectively, as “Rights Agent”).

RECITALS

WHEREAS, the Company, Dio Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of the Company (“Merger Sub”), and Dianthus Therapeutics, Inc., a Delaware corporation (“Dianthus”), have entered into an Agreement and Plan of Merger, dated as of May 2, 2023 (the “Merger Agreement”), pursuant to which Merger Sub will merge with and into Dianthus, with Dianthus surviving the Merger as a wholly-owned subsidiary of Magenta;

WHEREAS, pursuant to the Merger Agreement, and in accordance with the terms and conditions thereof, the Company has agreed to provide to the Holders (as defined herein) contingent value rights as hereinafter described;

WHEREAS, the parties have done all things reasonably necessary to make the contingent value rights, when issued pursuant to the Merger Agreement and hereunder, the valid obligations of the Company and to make this Agreement a valid and binding agreement of the Company, in accordance with its terms; and

NOW, THEREFORE, in consideration of the premises and the consummation of the transactions referred to above, it is mutually covenanted and agreed, for the proportionate benefit of all Holders, as follows:

ARTICLE 1

DEFINITIONS

Section 1.1 Definitions. Capitalized terms used but not otherwise defined herein have the meanings ascribed thereto in the Merger Agreement. The following terms have the meanings ascribed to them as follows:

“Acting Holders” means, at the time of determination, the Holders of more than 30% of the outstanding CVRs, as reflected on the CVR Register.

“Assignee” has the meaning set forth in Section 7.5.

“Calendar Quarter” means the successive periods of three (3) consecutive calendar months ending on March 31, June 30, September 30 or December 31, for so long as this Agreement is in effect; provided, however that (a) the first Calendar Quarter shall commence on the date of this Agreement and shall end on the first September 30 thereafter, and (b) the last Calendar Quarter shall commence on the first day after the full Calendar Quarter immediately preceding the effective date of the termination or expiration of this Agreement and shall end on the effective date of the termination or expiration of this Agreement.

“Common Stock” means the common stock, $0.001 par value, of the Company.

“CVR” means a contingent contractual right of Holders to receive CVR Payments pursuant to the Merger Agreement and this Agreement.

“CVR Payment” means a cash payment equal to the Net Proceeds received by the Company in a given Calendar Quarter ending on or after [•]; provided, that the Company, in its reasonable discretion as resolved by the Company’s Board of Directors, may withhold up to 20% of any CVR Payment to provide for the satisfaction of (i) indemnity obligations under any Disposition Agreement in excess of any escrow fund established therein, in each case to the extent not already deducted as Permitted Deductions and (ii) any

Exhibit D – Page 1

Loss arising out of any third-party claims, demands, actions, or other proceedings relating to or in connection with any Potentially Transferable Assets during the CVR Term; provided, further, that any such withheld Net Proceeds shall be distributed (net of any Permitted Deductions satisfied therefrom) to the Holders no later than three (3) years following the date such Net Proceeds would have otherwise been distributed to the Holders in the CVR Payment from which such Net Proceeds were otherwise deducted; provided, further, that, such withholding shall not be permitted if (x) the applicable indemnification period under the applicable Disposition Agreement related to such CVR Payment has expired by its terms when the CVR Payment is received or (y) the maximum aggregate liability in respect of the applicable indemnification obligations has been held back or setoff (including any amounts deposited in escrow) by the purchaser or acquiror under the applicable Disposition Agreement.

“CVR Payment Amount” means with respect to each CVR Payment and each Holder, an amount equal to such CVR Payment divided by the total number of CVRs and then multiplied by the total number of CVRs held by such Holder as reflected on the CVR Register.

“CVR Payment Period” means a period equal to a Calendar Quarter ending at any time after the effective date of a Disposition Agreement.

“CVR Payment Statement” means, for a given CVR Payment Period during the CVR Term, a written statement of the Company, signed on behalf of the Company, setting forth in reasonable detail the calculation of the applicable CVR Payment for such CVR Payment Period.

“CVR Register” has the meaning set forth in Section 2.3(b).

“CVR Term” means the period beginning on the Closing and ending upon the third anniversary of this Agreement; provided that, with respect to any Disposition Agreement set forth on Schedule 1.1, the CVR Term shall extent until the latest date that the Company may earn a contingent, earnout, milestone or similar payment pursuant to such Disposition Agreement.

“Disposition” means the sale, license, transfer or disposition of any Potentially Transferable Asset (including any such sale or disposition of equity securities in any Subsidiary established by the Company to hold any right, title or interest in or to any Potentially Transferable Asset).

“Disposition Agreement” means a definitive written agreement providing for a transaction or series of transactions between the Company or its Affiliates and any Person who is not an Affiliate of the Company regarding a Disposition, in each case, as set forth on Schedule 1.1 hereto or entered into during the period beginning on the Closing Date and ending December 31, 2023.

“Disposition Period” means the period beginning on the execution date of the Merger Agreement and ending on December 31, 2023.

“Gross Proceeds” means, without duplication, the sum of all cash consideration actually received by the Company or its Affiliates during the CVR Term in consideration for a Disposition pursuant to a Disposition Agreement.

“Holder” means, at the relevant time, a Person in whose name CVRs are registered in the CVR Register.

“Loss” has the meaning set forth in Section 3.2(g).

“Net Proceeds” means, for any CVR Payment Period, Gross Proceeds minus Permitted Deductions, all as calculated, to the extent in accordance with GAAP, in a manner consistent with the Company’s accounting practices and the most recently filed annual audited financial statements with the SEC, except as otherwise set forth herein. For clarity, to the extent Permitted Deductions exceed Gross Proceeds for any CVR Payment Period, any excess Permitted Deductions shall be applied against Gross Proceeds in subsequent CVR Payment Periods.

“Notice” has the meaning set forth in Section 7.1.

Exhibit D – Page 2

“Officer’s Certificate” means a certificate signed by the chief executive officer and the chief financial officer of the Company, in their respective official capacities.

“Party” means the Company or the Rights Agent.

“Permitted Deductions” means the sum of:

(a) any applicable Tax (including any applicable value added or sales taxes) imposed on Gross Proceeds and payable by the Company or any of its Affiliates (regardless of whether the due date for such Taxes arises during or after the Disposition Period) and, without duplication, any income or other similar Taxes payable by the Company or any of its Affiliates that would not have been incurred by the Company or any of its Affiliates but for the Gross Proceeds; provided that, for purposes of calculating income Taxes incurred by the Company or its Affiliates in respect of the Gross Proceeds, any such income Taxes shall be computed based on the gain recognized by the Company or its Affiliates from the Disposition after reduction for any net operating loss carryforwards or other Tax attributes of the Company or its Affiliates as of the Closing Date that are available to offset such gain after taking into account any limits of the usability of such attributes, including under Section 382 of the Code as determined by the Company’s tax advisers (and for the sake of clarity such income taxes shall be calculated without taking into account any net operating losses or other tax attributes generated by the Company or its Affiliates after the Closing Dates);

(b) any expenses incurred by the Company or any of its Affiliates in respect of its performance of this Agreement following the Closing Date or in respect of its performance of any Contract in connection with any Potentially Transferable Asset, including any costs related to the prosecution, maintenance or enforcement by the Company or any of its Subsidiaries of intellectual property rights (but excluding any costs related to a breach of this Agreement, including costs incurred in litigation in respect of the same);

(c) any expenses incurred or accrued by the Company or any of its Affiliates in connection with the negotiation, entry into and closing of any Disposition of any Potentially Transferable Asset, including any brokerage fee, finder’s fee, opinion fee, success fee, transaction fee, service fee or other fee, commission or expense owed to any broker, finder, investment bank, auditor, accountant, counsel, advisor or other third party in relation thereto;

(d) any Losses incurred or reasonably expected to be incurred by the Company or any of its Affiliates arising out of any third-party claims, demands, actions, or other proceedings relating to or in connection with any Disposition, including indemnification obligations of the Company or any of its Affiliates set forth in any Disposition Agreement;

(e) any proceeds in consideration for a Disposition pursuant to a Disposition Agreement included in the final determination of Magenta Net Cash in accordance with the Merger Agreement;

(f) any Liabilities borne by the Company or any of its Affiliates pursuant to Contracts related to Potentially Transferable Assets, including costs arising from the termination thereof; and

(g) any Liabilities existing or incurred during the CVR Term that would have been required to be included in the calculation of Magenta Net Cash to the extent not taken account in the calculation of Magenta Net Cash.

“Permitted Transfer” means a transfer of CVRs (a) upon death of a Holder by will or intestacy; (b) pursuant to a court order; (c) by operation of law (including by consolidation or merger) or without consideration in connection with the dissolution, liquidation or termination of any corporation, limited liability company, partnership or other entity; (d) in the case of CVRs held in book-entry or other similar nominee form, from a nominee to a beneficial owner and, if applicable, through an intermediary, to the extent allowable by DTC; or (e) as provided in Section 2.6.

Exhibit D – Page 3

“Potentially Transferable Assets” means the tangible and intangible assets primarily used in or primarily related to the Company’s MGTA-145 program, CD45-ADC program, MGTA-117 antibody, the E478 technology or the Igenica patent portfolio.

“Rights Agent” means the Rights Agent named in the first paragraph of this Agreement, until a successor Rights Agent will have become the Rights Agent pursuant to the applicable provisions of this Agreement, and thereafter “Rights Agent” will mean such successor Rights Agent.

ARTICLE 2

CONTINGENT VALUE RIGHTS

Section 2.1 Holders of CVRs; Appointment of Rights Agent.

(a) The CVRs represent the rights of Holders to receive CVR Payments pursuant to this Agreement. The initial Holders will be the holders of Magenta Common Stock as of immediately prior to the Effective Time. One CVR will be issued with respect to each share of Common Stock that is outstanding as of immediately prior to the Effective Time (including, for the avoidance of doubt, those shares of Common Stock issued upon settlement of Magenta Restricted Stock Units pursuant to Section 6.7 of the Merger Agreement).

(b) The Company hereby appoints the Rights Agent to act as Rights Agent for the Company in accordance with the express terms and conditions set forth in this Agreement, and the Rights Agent hereby accepts such appointment.

Section 2.2 Non-transferable. The CVRs may not be sold, assigned, transferred, pledged, encumbered or in any other manner transferred or disposed of, in whole or in part, other than through a Permitted Transfer. The CVRs will not be listed on any quotation system or traded on any securities exchange.

Section 2.3 No Certificate; Registration; Registration of Transfer; Change of Address.

(a) The CVRs will be issued in book-entry form only and will not be evidenced by a certificate or other instrument.

(b) The Rights Agent shall create and maintain a register (the “CVR Register”) for the purpose of registering CVRs and Permitted Transfers. The CVR Register will be created, and CVRs will be distributed, pursuant to written instructions to the Rights Agent from the Company. The CVR Register will initially show one position for Cede & Co. representing shares of Common Stock held by DTC on behalf of the street holders of the shares of Common Stock held by such holders as of immediately prior to the Effective Time. The Rights Agent will have no responsibility whatsoever directly or indirectly to the street name holders with respect to transfers of CVRs. With respect to any payments or issuances to be made under Section 2.4 below, the Rights Agent will accomplish the payment to any former street name holders of shares Common Stock by sending one lump-sum payment or issuance to DTC. The Rights Agent will have no responsibilities whatsoever with regard to the distribution of payments or shares of Common Stock by DTC to such street name holders.

(c) Subject to the restrictions on transferability set forth in Section 2.2, every request made to transfer a CVR must be in writing and accompanied by a written instrument of transfer in form reasonably satisfactory to the Rights Agent pursuant to its guidelines or procedures, including a guaranty of signature by an “eligible guarantor institution” that is a member or participant in the Securities Transfer Agents Medallion Program, duly executed and properly completed by the Holder thereof, the Holder’s attorney duly authorized in writing, the Holder’s personal representative or the Holder’s survivor, and setting forth in reasonable detail the circumstances relating to the transfer. Upon receipt of such written notice, the Rights Agent shall, subject to its reasonable determination that the transfer instrument is in proper form and the transfer otherwise complies with the other terms and conditions of this Agreement (including the provisions of Section 2.2), register the transfer of the CVRs in the CVR Register. The Company and Rights Agent may require evidence of payment of a sum sufficient to cover any stamp, documentary, registration, or other

Exhibit D – Page 4

Tax or governmental charge that is imposed in connection with any such registration of transfer (or evidence that such Taxes and charges are not applicable). The Rights Agent shall have no duty or obligation to take any action under any section of this Agreement that requires the payment by a Holder of a CVR of applicable taxes or charges unless and until the Rights Agent is satisfied that all such taxes or charges have been paid. All duly transferred CVRs registered in the CVR Register will be the valid obligations of the Company and will entitle the transferee to the same benefits and rights under this Agreement as those held immediately prior to the transfer by the transferor. No transfer of a CVR will be valid until registered in the CVR Register.

(d) A Holder may make a written request to the Rights Agent to change such Holder’s address of record in the CVR Register. The written request must be duly executed by the Holder. Upon receipt of such written notice, the Rights Agent shall, subject to its reasonable determination that the transfer instrument is in proper form, promptly record the change of address in the CVR Register. The Acting Holders may, without duplication, make a written request to the Rights Agent for a list containing the names, addresses and number of CVRs of the Holders that are registered in the CVR Register. Upon receipt of such written request from the Acting Holders, the Rights Agent shall promptly deliver a copy of such list to the Acting Holders.

(e) The Company will provide written instructions to the Rights Agent for the distribution of CVRs to holders of Common Stock as of immediately prior to the Effective Time (the “Record Time”). Subject to the terms and conditions of this Agreement and the Company’s prompt confirmation of the Effective Time, the Rights Agent shall effect the distribution of the CVRs, less any applicable tax withholding, to each holder of Common Stock as of the Record Time by the mailing of a statement of holding reflecting such CVRs.

Section 2.4 Payment Procedures.

(a) No later than forty-five (45) days following the end of each Calendar Quarter during the CVR Term beginning with the Calendar Quarter ending on [•], commencing with the first CVR Payment Period in which the Company or its Affiliates receives Gross Proceeds, the Company shall deliver to the Rights Agent a CVR Payment Statement for the such CVR Payment Period. Concurrent with the delivery of each CVR Payment Statement, on the terms and conditions of this Agreement, the Company shall pay the Rights Agent in U.S. dollars an amount equal to eighty percent (80%) of the Net Proceeds (if any) (subject to the proviso in the definition of the term “CVR Payment”) for the applicable CVR Payment Period. Such amount of Net Proceeds will be transferred by wire transfer of immediately available funds to an account designated in writing by the Rights Agent not less than twenty (20) Business Days prior to the date of the applicable payment. Upon receipt of the wire transfer referred to in the foregoing sentence, the Rights Agent shall promptly (and in any event, within ten (10) Business Days) pay, by check mailed, first-class postage prepaid, to the address each Holder set forth in the CVR Register at such time or by other method of deliver as specified by the applicable Holder in writing to the Rights Agent, an amount equal to such Holder’s CVR Payment Amount. The Rights Agent shall as soon as practicable after receipt of a CVR Payment Statement under this Section 2.4(b), send each Holder at its registered address a copy of such statement. For the avoidance of doubt the Company shall have no further liability in respect of the relevant CVR Payment upon delivery of such CVR Payment in accordance with this Section 2.4(b) and the satisfaction of each of the Company’s obligations set forth in this Section 2.4(b).

(b) The Rights Agent shall solicit from each Holder an IRS Form W-9 or applicable IRS Form W-8 at such time or times as is necessary to permit any payment under this Agreement to be made without U.S. federal backup withholding. That notwithstanding, the Company shall be entitled to deduct and withhold and hereby authorizes the Rights Agent to deduct and withhold, any tax or similar governmental charge or levy, that is required to be deducted or withheld under applicable law from any amounts payable pursuant to this Agreement (“Withholding Taxes”). To the extent the amounts are so withheld by the Company or the Rights Agent, as the case may be, and paid over to the appropriate

Exhibit D – Page 5

Governmental Authority, such withheld amounts shall be treated for all purposes of this Agreement as having been paid to the person in respect of whom such deduction and withholding was made. In the event the Company becomes aware that a payment under this Agreement is subject to Withholding Taxes (other than U.S. federal backup withholding), the Company shall use commercially reasonable efforts to provide written notice to the Rights Agent and the Rights Agent shall use commercially reasonable efforts to provide written notice of such Withholding Taxes to the applicable Holders and the Company and the Holders shall use commercially reasonable efforts cooperate with one another to minimize taxes required by applicable law to be withheld or deducted from any payments made under this Agreement. For the avoidance of doubt, in the event that notice has been provided to an applicable Holder pursuant to this Section 2.4(c), no further notice shall be required to be given for any future payments of such Withholding Tax. The Company will use commercially reasonable efforts to provide withholding and reporting instructions in writing (email being sufficient) to the Rights Agent from time to time as relevant, and upon reasonable request of the Rights Agent. The Rights Agent shall have no responsibilities with respect to tax withholding, reporting or payment except as set forth herein or as specifically instructed by the Company.

(c) Any portion of a CVR Payment that remains undistributed to the Holders six (6) months after the applicable Calendar Quarter end (including by means of uncashed checks or invalid addresses on the CVR Register) will be delivered by the Rights Agent to the Company or a person nominated in writing by the Company (with written notice thereof from the Company to the Rights Agent), and any Holder will thereafter look only to the Company for payment of such CVR Payment (which shall be without interest).

(d) If any CVR Payment (or portion thereof) remains unclaimed by a Holder two (2) years after the applicable Calendar Quarter end (or immediately prior to such earlier date on which such CVR Payment would otherwise escheat to or become the property of any Governmental Authority), such CVR Payment (or portion thereof) will, to the extent permitted by applicable Law, become the property of the Company and will be transferred to the Company or a person nominated in writing by the Company (with written notice thereof from the Company to the Rights Agent), free and clear of all claims or interest of any Person previously entitled thereto, and no consideration or compensation shall be payable therefor. Neither the Company nor the Rights Agent will be liable to any Person in respect of a CVR Payment delivered to a public official pursuant to any applicable abandoned property, escheat or similar legal requirement under applicable Law. In addition to and not in limitation of any other indemnity obligation herein, the Company agrees to indemnify and hold harmless the Rights Agent with respect to any liability, penalty, cost or expense the Rights Agent may incur or be subject to in connection with transferring such property to the Company, a public office or a person nominated in writing by the Company.

Section 2.5 No Voting, Dividends or Interest; No Equity or Ownership Interest.

(a) If and when issued, the CVRs will not have any voting or dividend rights, and interest will not accrue on any amounts payable in respect of CVRs to any Holder.

(b) If and when issued, the CVRs will not represent any equity or ownership interest in the Company or in any constituent company to the Merger. It is hereby acknowledged and agreed that a CVR shall not constitute a security of the Company.

(c) Nothing contained in this Agreement shall be construed as conferring upon any Holder, by virtue of the CVRs, any rights or obligations of any kind or nature whatsoever as a stockholder or member of the Company or any of its subsidiaries either at law or in equity. The rights of any Holder and the obligations of the Company and its Affiliates and their respective officers, directors and controlling Persons are contract rights limited to those expressly set forth in this Agreement.

(d) It is hereby acknowledged and agreed that the CVRs and the possibility of any payment hereunder with respect thereto are highly speculative and subject to numerous factors outside of the Company’s control, and there is no assurance that Holders will receive any payments under this Agreement or in connection with the CVRs. Each Holder acknowledges that it is highly possible that no Disposition

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will occur prior to the expiration of the Disposition Period and that there will not be any Gross Proceeds that may be the subject of a CVR Payment Amount. It is further acknowledged and agreed that neither the Company nor its Affiliates owe, by virtue of their obligations under this Agreement, a fiduciary duty or any implied duties to the Holders and the parties hereto intend solely the express provisions of this Agreement to govern their contractual relationship with respect to the CVRs. It is acknowledged and agreed that this Section 2.5(d) is an essential and material term of this Agreement.

Section 2.6 Ability to Abandon CVR. A Holder may at any time, at such Holder’s option, abandon all of such Holder’s remaining rights represented by CVRs by transferring such CVR to the Company or a Person nominated in writing by the Company (with written notice thereof from the Company to the Rights Agent) without consideration in compensation therefor, and such rights will be cancelled, with the Rights Agent being promptly notified in writing by the Company of such transfer and cancellation. Nothing in this Agreement is intended to prohibit the Company or its Affiliates from offering to acquire or acquiring CVRs, in private transactions or otherwise, for consideration in its sole discretion.

ARTICLE 3

THE RIGHTS AGENT

Section 3.1 Certain Duties and Responsibilities.

(a) The Rights Agent will not have any liability for any actions taken or not taken in connection with this Agreement, except to the extent such liability arises as a result of the willful misconduct, bad faith or gross negligence of the Rights Agent (in each case as determined by a final non-appealable judgment of court of competent jurisdiction). Notwithstanding anything in this Agreement to the contrary, any liability of the Rights Agent under this Agreement will be limited to the amount of annual fees paid by the Company to the Rights Agent in connection with this Agreement (but not including reimbursable expenses and other charges) during the eighteen (18) months immediately preceding the event for which recovery from the Rights Agent is being sought. Anything to the contrary notwithstanding, in no event will the Rights Agent be liable for special, punitive, indirect, incidental or consequential loss or damages of any kind whatsoever (including, without limitation, lost profits), even if the Rights Agent has been advised of the likelihood of such loss or damages, and regardless of the form of action.

(b) The Rights Agent shall not have any duty or responsibility in the case of the receipt of any written demand from any Holder with respect to any action or default by any person or entity, including, without limiting the generality of the foregoing, any duty or responsibility to initiate or attempt to initiate any proceedings at law or otherwise or to make any demand upon the Company or Dianthus. The Rights Agent may (but shall not be required to) enforce all rights of action under this Agreement and any related claim, action, suit, audit, investigation or proceeding instituted by the Rights Agent may be brought in its name as the Rights Agent and any recovery in connection therewith will be for the proportionate benefit of all the Holders, as their respective rights or interests may appear on the CVR Register.

Section 3.2 Certain Rights of Rights Agent.

(a) The Rights Agent undertakes to perform such duties and only such duties as are specifically set forth in this Agreement, and no implied covenants or obligations will be read into this Agreement against the Rights Agent.

(b) The Rights Agent may rely and will be protected by the Company in acting or refraining from acting upon any resolution, certificate, statement, instrument, opinion, report, notice, request, direction, consent, order or other paper or document reasonably believed by it to be genuine and to have been signed or presented by or on behalf of the Company or, with respect to Section 2.3(d), the Acting Holders.

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(c) Whenever the Rights Agent deems it desirable that a matter be proved or established prior to taking or omitting any action hereunder, the Rights Agent may rely upon an Officer’s Certificate, which certificate shall be full authorization and protection to the Rights Agent, and the Rights Agent shall, in the absence of bad faith, gross negligence or willful misconduct (each as determined by a final non-appealable judgment of a court of competent jurisdiction) on its part, not incur any liability and shall be held harmless by the Company for or in respect of any action taken or omitted to be taken by it under the provisions of this Agreement in reliance upon such Officer’s Certificate.

(d) The Rights Agent may engage and consult with counsel of its selection, and the advice or opinion of such counsel will, in the absence of bad faith, gross negligence or willful misconduct (in each case, as determined by a final, non-appealable judgment of a court of competent jurisdiction) on the part of the Rights Agent, be full and complete authorization and protection in respect of any action taken or not taken by the Rights Agent in reliance thereon.

(e) Any permissive rights of the Rights Agent hereunder will not be construed as a duty.

(f) The Rights Agent will not be required to give any note or surety in respect of the execution of its powers or otherwise under this Agreement.

(g) The Company agrees to indemnify the Rights Agent for, and to hold the Rights Agent harmless from and against, any loss, liability, damage, judgment, fine, penalty, cost or expense (each, a “Loss”) suffered or incurred by the Rights Agent and arising out of or in connection with the Rights Agent’s performance of its obligations under this Agreement, including the reasonable and documented costs and expenses of defending the Rights Agent against any claims, charges, demands, actions or suits arising out of or in connection in connection with the execution, acceptance, administration, exercise and performance of its duties under this Agreement, including the costs and expenses of defending against any claim of liability arising therefrom, directly or indirectly, or enforcing its rights hereunder, except to the extent such Loss has been determined by a final non-appealable decision of a court of competent jurisdiction to have resulted from the Rights Agent’s gross negligence, bad faith or willful misconduct; provided that this Section 3.2(g) shall not apply with respect to income, receipt, franchise or similar Taxes levied against the Rights Agent by a Governmental Authority.

(h) The Company agrees (i) to pay the fees of the Rights Agent in connection with the Rights Agent’s performance of its obligations hereunder as set forth in Exhibit A and agreed upon in writing by the Rights Agent and the Company on or prior to the date of this Agreement, and (ii) to reimburse the Rights Agent for all reasonable and documented out-of-pocket expenses and other disbursements incurred in the preparation, delivery, negotiation, amendment, administration and execution of this Agreement and the exercise and performance of its duties hereunder, including all stamp and transfer Taxes (and excluding for the avoidance of doubt, any income, receipt, franchise or similar Taxes levied against the Rights Agent by a Governmental Authority) and governmental charges, incurred by the Rights Agent in the performance of its obligations under this Agreement, except that the Company will have no obligation to pay the fees of the Rights Agent or reimburse the Rights Agent for the fees of counsel in connection with any lawsuit initiated by the Rights Agent on behalf of itself or the Holders, except in the case of any suit enforcing the provisions of Section 2.4(a), Section 2.4(b) or Section 3.2(g), if the Company is found by a court of competent jurisdiction to be liable to the Rights Agent or the Holders, as applicable in such suit.

(i) No provision of this Agreement shall require the Rights Agent to expend or risk its own funds or otherwise incur any financial liability in the performance of any of its duties hereunder or in the exercise of any of its rights or powers if it believes that repayment of such funds or adequate indemnification against such risk or liability is not reasonably assured to it.

(j) The Rights Agent shall have no responsibility to the Company, any holders of CVRs, any holders of shares of Common Stock or any other Person for interest or earnings on any moneys held by the Rights Agent pursuant to this Agreement.

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(k) The Rights Agent shall not be subject to, nor be required to comply with, or determine if any Person has complied with, the Merger Agreement or any other agreement between or among any the Company, Dianthus or Holders, even though reference thereto may be made in this Agreement, or to comply with any notice, instruction, direction, request or other communication, paper or document other than as expressly set forth in this Agreement.

(l) Subject to applicable Law, (i) the Rights Agent and any shareholder, affiliate, director, officer or employee of the Rights Agent may buy, sell or deal in any securities of the Company or Dianthus or become peculiarly interested in any transaction in which such parties may be interested, or contract with or lend money to such parties or otherwise act as fully and freely as though it were not the Rights Agent under this Agreement, and (ii) nothing herein will preclude the Rights Agent from acting in any other capacity for the Company or for any other Person.

(m) In the event the Rights Agent reasonably believes any ambiguity or uncertainty exists hereunder or in any notice, instruction, direction, request or other communication, paper or document received by the Rights Agent hereunder, the Rights Agent shall, as soon as practicable, provide notice to the Company, and the Rights Agent, may, in its sole discretion, refrain from taking any action, and shall be fully protected and shall not be liable in any way to the Company or any Holder or any other Person for refraining from taking such action, unless the Rights Agent receives written instructions from the Company or such Holder or other Person which eliminate such ambiguity or uncertainty to the reasonable satisfaction of the Rights Agent;

(n) The Rights Agent may execute and exercise any of the rights or powers hereby vested in it or perform any duty hereunder either itself or by or through its attorney or agents and the Rights Agent shall not be answerable or accountable for any act, default, neglect or misconduct of any such attorney or agents or for any loss to the Company or Dianthus resulting from any such act, default, neglect or misconduct, absent gross negligence, bad faith or willful misconduct (each as determined by a final non-appealable judgment of a court of competent jurisdiction) in the selection and continued employment thereof.

(o) The Rights Agent shall not be liable for or by reason of any of the statements of fact or recitals contained in this Agreement (except its countersignature thereof) or be required to verify the same, and all such statements and recitals are and shall be deemed to have been made by the Company only.

(p) The Rights Agent shall act hereunder solely as agent for the Company and shall not assume any obligations or relationship of agency or trust with any of the owners or holders of the CVRs. The Rights Agent shall not have any duty or responsibility in the case of the receipt of any written demand from any Holders with respect to any action or default by the Company, including, without limiting the generality of the foregoing, any duty or responsibility to initiate or attempt to initiate any proceedings at law or otherwise or to make any demand upon the Company.

(q) The Rights Agent may rely on and be fully authorized and protected in acting or failing to act upon (a) any guaranty of signature by an “eligible guarantor institution” that is a member or participant in the Securities Transfer Agents Medallion Program or other comparable “signature guarantee program” or insurance program in addition to, or in substitution for, the foregoing; or (b) any law, act, regulation or any interpretation of the same even though such law, act, or regulation may thereafter have been altered, changed, amended or repealed.

(r) The Rights Agent shall not be liable or responsible for any failure of the Company to comply with any of its obligations relating to any registration statement filed with the Securities and Exchange Commission or this Agreement, including without limitation obligations under applicable regulation or law.

(s) The obligations of the Company and the rights of the Rights Agent under this Section 3.2, Section 3.1 and Section 2.4 shall survive the expiration of the CVRs and the termination of this Agreement and the resignation, replacement or removal of the Rights Agent.

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Section 3.3 Resignation and Removal; Appointment of Successor.

(a) The Rights Agent may resign at any time by written notice to the Company. Any such resignation notice shall specify the date on which such resignation will take effect (which shall be at least thirty (30) days following the date that such resignation notice is delivered), and such resignation will be effective on the earlier of (x) the date so specified and (y) the appointment of a successor Rights Agent.

(b) The Company will have the right to remove the Rights Agent at any time by written notice to the Rights Agent, specifying the date on which such removal will take effect. Such notice will be given at least thirty (30) days prior to the date so specified (or, if earlier, the appointment of the successor Rights Agent).

(c) If the Rights Agent resigns, is removed or becomes incapable of acting, the Company will promptly appoint a qualified successor Rights Agent. Notwithstanding the foregoing, if the Company fails to make such appointment within a period of thirty (30) days after giving notice of such removal or after it has been notified in writing of such resignation or incapacity by the resigning or incapacitated Rights Agent, then the incumbent Rights Agent may apply to any court of competent jurisdiction for the appointment of a new Rights Agent. The successor Rights Agent so appointed will, upon its acceptance of such appointment in accordance with this Section 3.3(c) and Section 3.4, become the Rights Agent for all purposes hereunder.

(d) The Company will give notice to the Holders of each resignation or removal of the Rights Agent and each appointment of a successor Rights Agent in accordance with Section 7.2. Each notice will include the name and address of the successor Rights Agent. If the Company fails to send such notice within ten (10) Business Days after acceptance of appointment by a successor Rights Agent, the successor Rights Agent will cause the notice to be mailed at the expense of the Company.

(e) Notwithstanding anything to the contrary in this Section 3.3, unless consented to in writing by the Acting Holders, the Company will not appoint as a successor Rights Agent any Person that is not a stock transfer agent of national reputation or the corporate trust department of a commercial bank.

(f) The Rights Agent will reasonably cooperate with the Company and any successor Rights Agent in connection with the transition of the duties and responsibilities of the Rights Agent to the successor Rights Agent, including the transfer of all relevant data, including the CVR Register, to the successor Rights Agent, but such predecessor Rights Agent shall not be required to make any additional expenditure or assume any additional liability in connection with the foregoing.

Section 3.4 Acceptance of Appointment by Successor. Every successor Rights Agent appointed hereunder will, at or prior to such appointment, execute, acknowledge and deliver to the Company and to the resigning or removed Rights Agent an instrument accepting such appointment and a counterpart of this Agreement, and such successor Rights Agent, without any further act, deed or conveyance, will become vested with all the rights, powers, trusts and duties of the Rights Agent; provided that upon the request of the Company or the successor Rights Agent, such resigning or removed Rights Agent will execute and deliver an instrument transferring to such successor Rights Agent all the rights, powers and trusts of such resigning or removed Rights Agent.

ARTICLE 4

COVENANTS

Section 4.1 List of Holders. The Company will furnish or cause to be furnished to the Rights Agent, in such form as the Company receives from the Company’s transfer agent (or other agent performing similar services for the Company), the names and addresses of the Holders within fifteen (15) Business Days following the Closing Date.

Section 4.2 No Obligations of Public Company. Notwithstanding anything herein to the contrary, and for the avoidance of doubt, (a) the Company and its Affiliates shall have the power and right to control all aspects of their businesses and operations (and all of their assets and products), and subject to its compliance

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with the terms of this Agreement, the Company and its Affiliates may exercise or refrain from exercising such power and right as it may deem appropriate and in the best overall interests of the Company and its Affiliates and its and their stockholders, rather than the interest of the Holders, (b) none of the Company or any of its Affiliates (or any directors, officer, employee, or other representative of the foregoing) owes any fiduciary duty or similar duty to any Holder in respect of the Potentially Transferable Assets, and (c) following the Disposition Period, the Company shall be permitted to take any action in respect of the Potentially Transferable Assets in order to satisfy any wind-down and termination Liabilities of the Potentially Transferable Assets.

Section 4.3 Prohibited Actions. Unless approved by the Acting Holders, prior to the end of the Disposition Period, the Company shall not grant any lien, security interest, pledge or similar interest in any Potentially Transferable Assets or any Net Proceeds. Unless approved by the Acting Holders, prior to end of the Disposition Period, the Company shall not, and shall not permit its Affiliates to, grant, assign, transfer or otherwise convey any Potentially Transferrable Assets (including any option to obtain rights) to any third party.

Section 4.4 Books and Records. Until the end of the CVR Term, the Company shall, and shall cause its Affiliates to, keep true, complete and accurate records in sufficient detail to enable the Rights Agent to confirm the applicable CVR Payment Amount payable hereunder in accordance with the terms specified in this Agreement.

Section 4.5 Audits. Until the expiration of this Agreement and for a period of one (1) year thereafter, the Company shall keep complete and accurate records in sufficient detail to support the accuracy of the payments due hereunder. The Acting Holders shall have the right to cause an independent accounting firm reasonably acceptable to the Company to audit such records for the sole purpose of confirming payments for a period covering not more than the date commencing with the first CVR Payment Period in which the Company or its Affiliates receives Gross Proceeds and ending on the last day of the CVR Term. The Company may require such accounting firm to execute a reasonable confidentiality agreement with the Company prior to commencing the audit. The accounting firm shall disclose to Rights Agent or the Acting Holders, as applicable, only whether the reports are correct or not and the specific details concerning any discrepancies. No other information shall be shared. Such audits may be conducted during normal business hours upon reasonable prior written notice to the Company, but no more than frequently than once per year. No accounting period of the Company shall be subject to audit more than one time by the Acting Holders, as applicable, unless after an accounting period has been audited by the Acting Holders, as applicable, the Company restates its financial results for such accounting period, in which event the Acting Holders, as applicable, may conduct a second audit of such accounting period in accordance with this Section 4.5. Adjustments (including remittances of underpayments or overpayments disclosed by such audit) shall be made by the Company to reflect the results of such audit, which adjustments shall be paid promptly following receipt of an invoice therefor. Whenever such an adjustment is made, the Company shall promptly prepare a certificate setting forth such adjustment, and a brief, reasonably detailed statement of the facts, computation and methodology accounting for such adjustment to the extent not already reflected in the audit report and promptly file with the Rights Agent a copy of such report and promptly deliver to the Rights Agent a revised CVR Payment Statement for the relevant CVR Payment Period. The Rights Agent shall be fully protected in relying on any such report and on any adjustment or statement therein contained and shall have no duty or liability with respect to, and shall not be deemed to have knowledge of any such adjustment or any such event unless and until it shall have received such report. The Acting Holders, as applicable, shall bear the full cost and expense of such audit unless such audit discloses an underpayment by the Company of ten percent (10%) or more of the CVR Payment Amount due under this Agreement, in which case the Company shall bear the full cost and expense of such audit. The Rights Agent shall be entitled to rely on any audit report delivered by the independent accounting firm pursuant to this Section 4.5.

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ARTICLE 5

AMENDMENTS

Section 5.1 Amendments Without Consent of Holders or Rights Agent.

(a) The Company, at any time and from time to time, may (without the consent of any Person, other than the Rights Agent, with such consent not to be unreasonably withheld, conditioned or delayed) enter into one or more amendments to this Agreement for any of the following purposes:

(i) to evidence the appointment of another Person as a successor Rights Agent and the assumption by any successor Rights Agent of the covenants and obligations of the Rights Agent herein in accordance with the provisions hereof;

(ii) subject to Section 6.1, to evidence the succession of another person to the Company and the assumption of any such successor of the covenants of the Company outlined herein in a transaction contemplated by Section 6.1;

(iii) to add to the covenants of the Company such further covenants, restrictions, conditions or provisions as the Company and the Rights Agent will consider to be for the protection and benefit of the Holders; provided that in each case, such provisions do not adversely affect the interests of the Holders;

(iv) to cure any ambiguity, to correct or supplement any provision in this Agreement that may be defective or inconsistent with any other provision in this Agreement, or to make any other provisions with respect to matters or questions arising under this Agreement; provided that, in each case, such provisions do not adversely affect the interests of the Holders;

(v) as may be necessary or appropriate to ensure that the CVRs are not subject to registration under the Securities Act or the Exchange Act and the rules and regulations promulgated thereunder, or any applicable state securities or “blue sky” laws;

(vi) as may be necessary or appropriate to ensure that the Company is not required to produce a prospectus or an admission document in order to comply with applicable Law;

(vii) to cancel the CVRs (i) in the event that any Holder has abandoned its rights in accordance with Section 2.6, (ii) in order to give effect to the provisions of Section 2.7 or (iii) following a transfer of such CVRs to the Company or its Affiliates in accordance with Section 2.2 or Section 2.3;

(viii) as may be necessary or appropriate to ensure that the Company complies with applicable Law; or

(ix) to effect any other amendment to this Agreement for the purpose of adding, eliminating or changing any provisions of this Agreements, provided that, in each case, such additions, eliminations or changes do not adversely affect the interests of the Holders.

(b) Promptly after the execution by the Company of any amendment pursuant to this Section 5.1, the Company will (or will cause the Rights Agent to) notify the Holders in general terms of the substance of such amendment in accordance with Section 7.2.

Section 5.2 Amendments with Consent of Holders.

(a) In addition to any amendments to this Agreement that may be made by the Company without the consent of any Holder pursuant to Section 5.1, with the consent of the Acting Holders (whether evidenced in a writing or taken at a meeting of the Holders), the Company and the Rights Agent may enter into one or more amendments to this Agreement for the purpose of adding, eliminating or amending any provisions of this Agreement, even if such addition, elimination or amendment is adverse to the interests of the Holders.

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(b) Promptly after the execution by the Company and the Rights Agent of any amendment pursuant to the provisions of this Section 5.2, the Company will (or will cause the Rights Agent to) notify the Holders in general terms of the substance of such amendment in accordance with Section 7.2.

Section 5.3 Effect of Amendments.

Upon the execution of any amendment under this Article 5, this Agreement will be modified in accordance therewith, such amendment will form a part of this Agreement for all purposes and every Holder will be bound thereby. Upon the delivery of a certificate from an appropriate officer of the Company which states that the proposed supplement or amendment is in compliance with the terms of this Section 5, the Rights Agent shall execute such supplement or amendment. Notwithstanding anything in this Agreement to the contrary, the Rights Agent shall not be required to execute any supplement or amendment to this Agreement that it has determined would adversely affect its own rights, duties, obligations or immunities under this Agreement. No supplement or amendment to this Agreement shall be effective unless duly executed by the Rights Agent.

ARTICLE 6

CONSOLIDATION, MERGER, SALE OR CONVEYANCE

Section 6.1 The Company May Not Consolidate, Etc. During the CVR Term, the Company shall not consolidate with or merge into any other Person or convey, transfer or lease its properties and assets substantially as an entirety to any Person, unless:

(a) the Person formed by such consolidation or into which the Company is merged or the Person that acquires by conveyance or transfer, or that leases, the properties and assets of the Company substantially as an entirety (the “Surviving Person”) shall expressly assume payment of amounts on all CVRs (when and as due hereunder) and the performance of every duty and covenant of this Agreement on the part of the Company to be performed or observed; and

(b) The Company has delivered to the Rights Agent an Officer’s Certificate, stating that such consolidation, merger, conveyance, transfer or lease complies with this Article 6 and that all conditions precedent herein provided for relating to such transaction have been complied with.

Section 6.2 Successor Substituted. Upon any consolidation of or merger by the Company with or into any other Person, or any conveyance, transfer or lease of the properties and assets substantially as an entirety to any Person in accordance with Section 6.1, the Surviving Person shall succeed to, and be substituted for, and may exercise every right and power of, and shall assume all of the obligations of the Company under this Agreement with the same effect as if the Surviving Person had been named as the Company herein.

ARTICLE 7

MISCELLANEOUS

Section 7.1 Notices to Rights Agent and to the Company. All notices, requests and other communications (each, a “Notice”) to any party hereunder shall be in writing and shall be deemed to have been duly delivered and received hereunder (a) one (1) Business Day after being sent for next Business Day delivery, fees prepaid, via a reputable international overnight courier service, (b) upon delivery in the case of delivery in person, by FedEx or other internationally recognized overnight courier service or (c) on the date delivered in the place of delivery if sent by email or facsimile (with a written or electronic confirmation of delivery) prior to 6:00 p.m. (New York City time), otherwise on the next succeeding Business Day, in each case to the intended recipient as set forth below:

if to the Rights Agent, to:

Computershare Trust Company, N.A.

Computershare Inc.

150 Royall Street

Canton, MA 02021

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if to the Company, to:

Dianthus Therapeutics, Inc.

7 Times Square

New York, New York, 10036

Attention: Ryan Savitz

Email:

with a copy, which shall not constitute notice, to:

Gibson, Dunn & Crutcher LLP

555 Mission Street, Suite 3000

San Francisco, CA 94105

Attention: Ryan Murr, Branden Berns, Chris Trester

Email:

or to such other address or facsimile number as such party may hereafter specify for the purpose by notice to the other parties hereto.

Section 7.2 Notice to Holders. All Notices required to be given to the Holders will be given (unless otherwise herein expressly provided) in writing and mailed, first-class postage prepaid, to each Holder at such Holder’s address as set forth in the CVR Register, not later than the latest date, and not earlier than the earliest date, prescribed for the sending of such Notice, if any, and will be deemed given on the date of mailing. In any case where notice to the Holders is given by mail, neither the failure to mail such Notice, nor any defect in any Notice so mailed, to any particular Holder will affect the sufficiency of such Notice with respect to other Holders.

Section 7.3 Entire Agreement. As between the Company and the Rights Agent, this Agreement constitutes the entire agreement between the parties with respect to the subject matter of this Agreement, notwithstanding the reference to any other agreement herein, and supersedes all prior agreements and understandings, both written and oral, among or between any of the parties with respect to the subject matter of this Agreement.

Section 7.4 Merger or Consolidation or Change of Name of Rights Agent. Any Person into which the Rights Agent or any successor Rights Agent may be merged or with which it may be consolidated, or Person resulting from any merger or consolidation to which the Rights Agent or any successor Rights Agent shall be a party, or any Person succeeding to the stock transfer or other shareholder services business of the Rights Agent or any successor Rights Agent, shall be the successor to the Rights Agent under this Agreement without the execution or filing of any paper or any further act on the part of any of the parties hereto, provided that such Person would be eligible for appointment as a successor Rights Agent under the provisions of Section 3.3. The purchase of all or substantially all of the Rights Agent’s assets employed in the performance of transfer agent activities shall be deemed a merger or consolidation for purposes of this Section 7.4.

Section 7.5 Successors and Assigns. This Agreement will be binding upon, and will be enforceable by and inure solely to the benefit of, the Holders, the Company and the Rights Agent and their respective successors and assigns. Except for assignments pursuant to Section 7.4, the Rights Agent may not assign this Agreement without the Company’s prior written consent. Subject to Section 5.1(a)(ii) and Article 6 hereof, the Company may assign, in its sole discretion and without the consent of any other party, any or all of its rights, interests and obligations hereunder to one or more of its Affiliates or to any Person with whom the Company is merged or consolidated, or any entity resulting from any merger or consolidation to which the Company shall be a party (each, an “Assignee”); provided, that in connection with any assignment to an Assignee, the Company shall agree to remain liable for the performance by the Company of its obligations hereunder (to the extent the Company exists following such assignment). The Company or an Assignee may not otherwise assign this Agreement without the prior consent of the Acting Holders (such consent not to be unreasonably withheld, conditioned or delayed). Any attempted assignment of this Agreement in violation of this Section 7.5 will be void ab initio and of no effect.

Exhibit D – Page 14

Section 7.6 Benefits of Agreement; Action by Acting Holders. Nothing in this Agreement, express or implied, will give to any Person (other than the Company, the Rights Agent, the Holders and their respective permitted successors and assigns hereunder) any benefit or any legal or equitable right, remedy or claim under this Agreement or under any covenant or provision herein contained, all such covenants and provisions being for the sole benefit of the Company, the Rights Agent, the Holders and their permitted successors and assigns. The Holders will have no rights hereunder except as are expressly set forth herein. Except for the rights of the Rights Agent set forth herein, the Acting Holders will have the sole right, on behalf of all Holders, by virtue of or under any provision of this Agreement, to institute any action or proceeding at law or in equity with respect to this Agreement, and no individual Holder or other group of Holders will be entitled to exercise such rights.

Section 7.7 Governing Law. This Agreement and the CVRs will be governed by, and construed in accordance with, the laws of the State of Delaware without regard to the conflicts of law rules of such state.

Section 7.8 Jurisdiction. In any action or proceeding between any of the parties hereto arising out of or relating to this Agreement or any of the transactions contemplated hereby, each of the parties hereto: (a) irrevocably and unconditionally consents and submits to the exclusive jurisdiction and venue of the Court of Chancery of the State of Delaware or, to the extent such court does not have subject matter jurisdiction, the Superior Court of the State of Delaware or the United States District Court for the District of Delaware; (b) agrees that all claims in respect of such action or proceeding shall be heard and determined exclusively in accordance with clause (a) of this Section 7.8; (c) waives any objection to laying venue in any such action or proceeding in such courts; (d) waives any objection that such courts are an inconvenient forum or do not have jurisdiction over any Party; and (e) agrees that service of process upon such Party in any such action or proceeding shall be effective if notice is given in accordance with Section 7.1 or Section 7.2 of this Agreement.

Section 7.9 WAIVER OF JURY TRIAL. EACH OF THE PARTIES HERETO HEREBY IRREVOCABLY WAIVES ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATED TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY. EACH PARTY CERTIFIES AND ACKNOWLEDGES THAT (I) NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER, (II) EACH PARTY UNDERSTANDS AND HAS CONSIDERED THE IMPLICATION OF THIS WAIVER, (III) EACH PARTY MAKES THIS WAIVER VOLUNTARILY, AND (IV) EACH PARTY HAS BEEN INDUCED TO ENTER INTO THIS AGREEMENT BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION 7.9.

Section 7.10 Severability Clause. In the event that any provision of this Agreement, or the application of any such provision to any Person or set of circumstances, is for any reason determined to be invalid, unlawful, void or unenforceable to any extent, the remainder of this Agreement, and the application of such provision to Persons or circumstances other than those as to which it is determined to be invalid, unlawful, void or unenforceable, will not be impaired or otherwise affected and will continue to be valid and enforceable to the fullest extent permitted by applicable Law. Upon such a determination, the parties hereto will negotiate in good faith to modify this Agreement so as to effect the original intent of the parties as closely as possible in a mutually acceptable manner in order that the transactions contemplated hereby be consummated as originally contemplated to the fullest extent possible; provided, however, that if an excluded provision shall affect the rights, immunities, liabilities, duties or obligations of the Rights Agent, the Rights Agent shall be entitled to resign immediately upon written Notice to the Company.

Exhibit D – Page 15

Section 7.11 Counterparts; Effectiveness. This Agreement may be signed in any number of counterparts, each of which will be deemed an original, with the same effect as if the signatures thereto and hereto were upon the same instrument. This Agreement or any counterpart may be executed and delivered by facsimile copies or delivered by electronic communications by portable document format (.pdf), each of which shall be deemed an original. This Agreement will become effective when each party hereto will have received a counterpart hereof signed by the other party hereto. Until and unless each party has received a counterpart hereof signed by the other party hereto, this Agreement will have no effect and no party will have any right or obligation hereunder (whether by virtue of any oral or written agreement or any other communication).

Section 7.12 Termination. This Agreement will automatically terminate and be of no further force or effect and, except as provided in Section 3.2, the parties hereto will have no further liability hereunder, and the CVRs will expire without any consideration or compensation therefor, upon the expiration of the CVR Term. The termination of this Agreement will not affect or limit the right of Holders to receive the CVR Payments under Section 2.4 to the extent earned prior to the termination of this Agreement, and the provisions applicable thereto will survive the expiration or termination of this Agreement until such CVR Payments have been made, if applicable.

Section 7.13 Funds. All funds received by Rights Agent under this Agreement that are to be distributed or applied by Rights Agent in the performance of services hereunder (the “Funds”) shall be held by Computershare, as agent for the Company, and deposited in one or more bank accounts to be maintained by Computershare in its name as agent for the Company. Until paid pursuant to the terms of this Agreement, The Rights Agent shall cause Computershare to hold the Funds through such accounts in: deposit accounts of commercial banks with Tier 1 capital exceeding $1 billion or with an average rating above investment grade by S&P (LT Local Issuer Credit Rating), Moody’s (Long Term Rating) and Fitch Ratings, Inc. (LT Issuer Default Rating) (each as reported by Bloomberg Finance L.P.). The Rights Agent and Computershare shall, in the absence of bad faith, gross negligence or willful misconduct (each as determined by a final non-appealable judgment of a court of competent jurisdiction) on its part, have no responsibility or liability for any diminution of the Funds that may result from any deposit made by Computershare in accordance with this paragraph, including any losses resulting from a default by any bank, financial institution or other third party. Computershare may from time to time receive interest, dividends or other earnings in connection with such deposits.

Section 7.15 Further Assurance by Company. The Company agrees that it will perform, execute, acknowledge and deliver or cause to be performed, executed, acknowledged and delivered all such further and other acts, instruments and assurances as may reasonably be required or requested by the Rights Agent for the carrying out or performing by the Rights Agent of the provisions of this Agreement.

Section 7.16 Construction.

(a) For purposes of this Agreement, whenever the context requires: singular terms will include the plural, and vice versa; the masculine gender will include the feminine and neuter genders; the feminine gender will include the masculine and neuter genders; and the neuter gender will include the masculine and feminine genders.

(b) As used in this Agreement, the words “include” and “including,” and variations thereof, will not be deemed to be terms of limitation, but rather will be deemed to be followed by the words “without limitation.”

(c) The headings contained in this Agreement are for convenience of reference only, will not be deemed to be a part of this Agreement and will not be referred to in connection with the construction or interpretation of this Agreement.

(d) Unless stated otherwise, “Article” and “Section” followed by a number or letter mean and refer to the specified Article or Section of this Agreement. The term “Agreement” and any reference in this Agreement to this Agreement or any other agreement or document includes, and is a reference to, this Agreement or such other agreement or document as it may have been, or may from time to time be, amended, restated, replaced, supplemented or novated and includes all schedules to it.

Exhibit D – Page 16

(e) A period of time is to be computed as beginning on the day following the event that began the period and ending at 4:30 p.m. on the last day of the period, if the last day of the period is a Business Day, or at 4:30 p.m. on the next Business Day if the last day of the period is not a Business Day.

(f) Any reference in this Agreement to a date or time shall be deemed to be such date or time in New York City, United States, unless otherwise specified. The parties hereto and the Company have participated jointly in the negotiation and drafting of this Agreement. In the event an ambiguity or question of intent or interpretation arises, this Agreement shall be construed as if drafted jointly by the parties and the Company and no presumption or burden of proof shall arise favoring or disfavoring any Person by virtue of the authorship of any provision of this Agreement.

(g) All references herein to “$” are to United States Dollars.

[Remainder of page intentionally left blank]

Exhibit D – Page 17

IN WITNESS WHEREOF, each of the parties has caused this Agreement to be executed as of the day and year first above written.

Exhibit D – Page 18

Exhibit 4.2

AMENDMENT NO. 1 TO

STOCKHOLDER RIGHTS AGREEMENT

This AMENDMENT NO. 1 TO STOCKHOLDER RIGHTS AGREEMENT (this “Amendment”) is dated as of May 2, 2023 (the “Effective Date”), and amends that certain Stockholder Rights Agreement, dated as of March 31, 2023 (the “Rights Agreement”), by and between Magenta Therapeutics, Inc., a Delaware corporation (the “Company”), and Computershare Trust Company, N.A., a federally chartered trust company, as rights agent (the “Rights Agent”). Capitalized terms used in this Amendment and not otherwise defined herein have the meanings given to them in the Rights Agreement.

WITNESSETH

WHEREAS, the Company has entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Dianthus Therapeutics, Inc. (the “Target”) and Dio Merger Sub, Inc. (“Merger Sub”), dated as of May 2, 2023, pursuant to which, among other things: (a) Merger Sub shall be merged with and into the Target (the “Merger”), whereupon the separate corporate existence of Merger Sub shall cease and the Target shall be the surviving company and a wholly-owned subsidiary of the Company; and (b) each share of Company Capital Stock (as defined in the Merger Agreement) issued and outstanding immediately prior to the Effective Time (as defined in the Merger Agreement) will be automatically converted into and thereafter represent the right to receive the Merger Consideration (as defined in the Merger Agreement), subject to the terms set forth in the Merger Agreement;

WHEREAS, pursuant to resolutions adopted on May 2, 2023 (the “Board Resolutions”), the board of directors of the Company (the “Board”) has adopted and approved the Merger Agreement;

WHEREAS, in accordance with Section 27 of the Rights Agreement, prior to the occurrence of a Section 11(a)(ii) Event, the Company may in its sole discretion supplement or amend the Rights Agreement in any respect without the approval of any holders of certificates representing shares of Common Stock of the Company, and the Rights Agent must, if the Company so directs, execute such supplement or amendment;

WHEREAS, the Rights are currently redeemable, no person is an Acquiring Person, and no Section 11(a)(ii) Event has occurred;

WHEREAS, pursuant to the Board Resolutions, and in connection with entering into the Merger Agreement, the Board has unanimously determined that an amendment to the Rights Agreement is advisable, fair to and in the best interests of the Company and its stockholders;

WHEREAS, pursuant to Section 27 of the Rights Agreement, the Rights Agent is directed to execute this Amendment.

NOW, THEREFORE, in consideration of the premises and the mutual agreements herein set forth herein, the parties hereto hereby agree as follows:

1. Amendment of the Rights Agreement.

A. Section 1 of the Rights Agreement is hereby amended by adding the following additional definitions:

“Effective Time” has the meaning ascribed to such term in the Merger Agreement.

“Merger” has the meaning ascribed to such term in the Merger Agreement.

“Merger Agreement” means the Agreement and Plan of Merger, dated as of May 2, 2023, among the Company, Target, and Merger Sub, as it may be amended from time to time.

“Merger Sub” means Dio Merger Sub, Inc.

“Target” means Dianthus Therapeutics, Inc.

B. The following is added as a new Section 36 of the Rights Agreement:

“Section 36. Exception for Merger Agreement. Notwithstanding anything to the contrary in this Agreement, as long as the Merger Agreement is not validly terminated, none of the approval, execution, delivery or performance of the Merger Agreement, or the consummation prior to the termination of the Merger Agreement of the Merger or any of the other transactions contemplated by the Merger Agreement, including the issuance of shares of common stock of the Company to the stockholders of the Target, in accordance with the terms of the Merger Agreement, shall: (a) result in a Stock Acquisition Date, a Distribution Date or in any way permit any Rights to be exercised pursuant to this Agreement, including, without limitation, Section 7 or otherwise, for consideration or exchanged pursuant to Section 24; (b) constitute a Section 11(a)(ii) Event or a Section 13 Event; (c) cause any of Target, Merger Sub or their respective Affiliates or Associates (each, a “Target Person”) to be deemed to be an “Acquiring Person” for any purpose in this Agreement (it being understood that future actions by any Target Person could still result in such Target Person being an Acquiring Person for purposes of this Agreement); or (d) cause any officer, director or employee of any Target Person to be deemed to be, solely by reason of such Person’s status or authority as such, the “Beneficial Owner” of or to “Beneficially Own” any securities that are “Beneficially Owned” by a Target Person, including in a fiduciary capacity. Nothing in this Agreement shall be construed to give any holder of Rights or any other Person any legal or equitable rights, remedy or claim under this Agreement in connection with the approval, execution, delivery or performance of the Merger Agreement, or the consummation prior to the termination of the Merger Agreement of the Merger or any of the other transactions contemplated by the Merger Agreement. Notwithstanding anything to the contrary in this Agreement, immediately prior to the Effective Time, but only if the Effective Time shall occur, and without any further action by the Rights Agent, the Company, Target, Merger Sub or any current or former holder of Rights, this Agreement, the Rights, and any right to exercise the Rights provided for hereunder shall terminate, expire and be void and of no further force or effect and such time shall be deemed the Expiration Date for all purposes of this Agreement.”

2. No Other Amendment; Effect of Amendment. Except as and to the extent expressly modified by this Amendment, the Rights Agreement and the exhibits thereto remain in full force and effect in all respects without any modification. This Amendment will be deemed an amendment to the Rights Agreement and will become effective on the Effective Date. In the event of a conflict or inconsistency between this Amendment and the Rights Agreement and the exhibits thereto, the provisions of this Amendment will govern.

3. Officer Certification. The officer of the Company executing this Amendment hereby certifies to the Rights Agent that the amendments to the Rights Agreement set forth in this Amendment are in compliance with Section 27 of the Rights Agreement and the certification contained in this Section 3 shall constitute the certification required by Section 27 of the Rights Agreement.

4. Counterparts. This Amendment may be executed in any number of counterparts and each of such counterparts will for all purposes be deemed to be an original, and all such counterparts will together constitute one and the same instrument, it being understood that all parties need not sign the same counterpart. A signature to this Amendment executed and/or transmitted electronically (including by fax and .pdf) will have the same authority, effect, and enforceability as an original signature. No party hereto may raise the use of

such electronic transmission to deliver a signature, or the fact that any signature or agreement or instrument was transmitted or communicated through such electronic transmission, as a defense to the formation of a contract, and each such party forever waives any such defense, except to the extent such defense relates to lack of authenticity.

5. Severability. If any term, provision, covenant or restriction of this Amendment is held by a court of competent jurisdiction or other authority to be invalid, void or unenforceable, the remainder of the terms, provisions, covenants and restrictions of this Amendment will remain in full force and effect and will in no way be affected, impaired or invalidated; provided, however, that if any such excluded term, provision, covenant or restriction adversely affects the rights, immunities, duties or obligations of the Rights Agent, then the Rights Agent shall be entitled to resign immediately.

6. Descriptive Headings. The descriptive headings of the several sections of this Amendment are inserted for convenience only and will not control or affect the meaning or construction of any of the provisions hereof.

7. Further Assurances. Each of the parties to this Amendment will reasonably cooperate and take such action as may be reasonably requested by the other party to carry out the provisions and purposes of this Amendment, the Rights Agreement and the transactions contemplated hereunder and thereunder.

8. Governing Law. This Amendment, and all claims or causes of action (whether in contract or in tort or otherwise, or whether at law (including at common law or by statute) or in equity) that may be based on, arise out of or relate to this Amendment, or the negotiation, execution, performance or subject matter of this Amendment, will be governed by and construed in accordance with the laws of the State of Delaware.

[Signature page follows]

IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be duly executed as of the day and year first written above.

[Signature Page to Amendment No. 1 to Stockholder Rights Agreement]

Exhibit 10.1

FORM OF COMPANY STOCKHOLDER SUPPORT AGREEMENT

This Support Agreement (this “Agreement”) is made and entered into as of May 2, 2023, by and among Dianthus Therapeutics, Inc., a Delaware corporation (the “Company”), Magenta Therapeutics, Inc., a Delaware corporation (“Magenta”), and the undersigned stockholder (the “Stockholder”) of the Company. Capitalized terms used herein but not otherwise defined shall have the respective meanings ascribed to such terms in the Merger Agreement (as defined below).

RECITALS

WHEREAS, concurrently with the execution and delivery hereof, Magenta, the Company and Dio Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Magenta (the “Merger Sub”), have entered into an Agreement and Plan of Merger (as such agreement may be amended or supplemented from time to time pursuant to the terms thereof, the “Merger Agreement”), pursuant to which Merger Sub will merge with and into the Company, with the Company surviving the merger as the surviving corporation and a wholly owned subsidiary of Magenta (the “Merger”) upon the terms and subject to the conditions set forth in the Merger Agreement.

WHEREAS, as of the date hereof, the Stockholder is the beneficial owner (as defined in Rule 13d-3 under the Exchange Act) of such number of shares of Company Capital Stock as indicated in Appendix A.

WHEREAS, as an inducement to the willingness of Magenta to enter into the Merger Agreement, Magenta has required that Stockholder enter into this Agreement.

NOW, THEREFORE, intending to be legally bound, the parties hereby agree as follows:

1. Certain Definitions. Capitalized terms used but not otherwise defined herein shall have the meanings ascribed thereto in the Merger Agreement. For all purposes of this Agreement, the following terms shall have the following respective meanings:

(a) “Constructive Sale” means, with respect to any security, a short sale with respect to such security, entering into or acquiring a derivative contract with respect to such security, entering into or acquiring a futures or forward contract to deliver such security or entering into any other hedging or other derivative transaction that has the effect of either directly or indirectly materially changing the economic benefits or risks of ownership of such security.

(b) “Shares” means (i) all shares of Company Capital Stock beneficially owned by the Stockholder as of the date hereof, and (ii) all additional shares of Company Capital Stock acquired and beneficially owned by the Stockholder during the period commencing with the execution and delivery of this Agreement and expiring on the Closing Date.

(c) “Transfer” or “Transferred” means, with respect to any security, the direct or indirect assignment, sale, transfer, tender, exchange, pledge or hypothecation, or the grant, creation or suffrage of a lien, security interest or encumbrance in or upon, or the gift, grant or

Page 1

placement in trust, or the Constructive Sale or other disposition of such security (including transfers by testamentary or intestate succession, by domestic relations order or other court order, or otherwise by operation of law) or any right, title or interest therein (including any right or power to vote to which the holder thereof may be entitled, whether such right or power is granted by proxy or otherwise), or the beneficial ownership thereof, the offer to make such a sale, transfer, Constructive Sale or other disposition, and each agreement, arrangement or understanding, whether or not in writing, to effect any of the foregoing.

2. Transfer and Voting Restrictions. The Stockholder covenants to Magenta as follows:

(a) Except as otherwise permitted by Section 2(c), during the period commencing with the execution and delivery of this Agreement and expiring on the Expiration Date (as defined below), the Stockholder shall not Transfer any of the Stockholder’s Shares, or publicly announce its intention to Transfer any of its Shares.

(b) Except as otherwise permitted by this Agreement or otherwise permitted or required by order of a court of competent jurisdiction or a Governmental Authority, the Stockholder will not commit any act that would restrict the Stockholder’s legal power, authority and right to vote all of the Shares held by the Stockholder or otherwise prevent or disable the Stockholder from performing any of his, her or its obligations under this Agreement. Without limiting the generality of the foregoing, except for this Agreement, the Amended and Restated Voting Agreement of the Company, dated as of April 6, 2022 (the “Voting Agreement”) and as otherwise permitted by this Agreement, the Stockholder shall not enter into any voting agreement with any person or entity with respect to any of the Stockholder’s Shares, grant any person or entity any proxy (revocable or irrevocable) or power of attorney with respect to any of the Shares, deposit any Shares in a voting trust or otherwise enter into any agreement or arrangement with any person or entity limiting or affecting the Stockholder’s legal power, authority or right to execute and deliver the Company Stockholder Written Consent.

(c) Notwithstanding anything else herein to the contrary, the Stockholder may, at any time, Transfer Shares (i) by will or other testamentary document or by intestacy, (ii) to any investment fund or other entity controlled or managed by the Stockholder or the investment adviser of general partner of the Stockholder, or an entity under common control or management with the Stockholders (in each case, directly or indirectly) (iii) to any member of the Stockholder’s immediate family (or, if the Stockholder is a corporation, partnership or other entity, to an immediate family member of a beneficial owner of the Shares held by the Stockholder), (iv) to any trust or other entity for the direct or indirect benefit of the Stockholder or the immediate family of the Stockholder (or, if the Stockholder is a corporation, partnership or other entity, for the direct or indirect benefit of an immediate family member of a beneficial owner of the Shares held by the Stockholder) or otherwise for estate tax or estate planning purposes, (v) in the case of a Stockholder who is not a natural person, by pro rata distributions from the Stockholder to its members, partners, or shareholders pursuant to the Stockholder’s organizational documents; provided, that in the cases of clauses (i)-(v), (x) such Transferred Shares shall continue to be bound by this Agreement and (y) the applicable direct transferee (if any) of such Transferred Shares shall have executed and delivered to Magenta and the Company a support agreement substantially identical to this Agreement upon consummation of the Transfer or (vi) to the extent required by applicable Law.

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(d) Notwithstanding anything to the contrary herein, nothing in this Agreement shall obligate the Stockholder to exercise any option or any other right to acquire any shares of Company Capital Stock.

3. Agreement to Vote Shares. The Stockholder covenants to the Company as follows:

(a) Until the Expiration Date, at any meeting of the stockholders of the Company, however called, and at every adjournment or postponement thereof, and on every action or approval by written consent of the stockholders of the Company, the Stockholder shall be present (in person or by proxy) and vote, or exercise its right to consent with respect to, all Shares held by the Stockholder (A) in favor of the adoption and approval of the Merger Agreement, (B) in favor of approval of the Contemplated Transactions, and (C) against any Acquisition Proposal.

(b) If the Stockholder is not the record holder, of Shares, the Stockholder agrees to take all actions necessary to cause the record holder and any nominees to be present (in person or by proxy) and vote all the Stockholder’s Shares in accordance with this Section 3.

(c) In the event of a stock split, stock dividend or distribution, or any change in the capital stock of the Company by reason of any split-up, reverse stock split, recapitalization, combination, reclassification, reincorporation, exchange of shares or the like, the term “Shares” shall be deemed to refer to and include such shares as well as all such stock dividends and distributions and any securities into which or for which any or all of such shares may be changed or exchanged or which are received in such transaction.

4. Action in Stockholder Capacity Only. The Stockholder is entering into this Agreement solely in the Stockholder’s capacity as the beneficial owner of its Shares and not in the Stockholder’s capacity as a director or officer of the Company. Nothing herein shall limit or affect the Stockholder’s ability to act as an officer or director of the Company.

5. Irrevocable Proxy. The Stockholder hereby revokes (or agrees to cause to be revoked) any proxies that the Stockholder has heretofore granted with respect to its Shares. In the event and to the extent that the Stockholder fails to vote the Shares in accordance with Section 3 at any applicable meeting of the stockholders of the Company or pursuant to any applicable written consent of the stockholders of the Company, the Stockholder shall be deemed to have irrevocably granted to, and appointed, the Company, and any individual designated in writing by it, and each of them individually, as his, her or its proxy and attorney-in-fact (with full power of substitution), for and in its name, place and stead, to vote his, her or its Shares in any action by written consent of Company stockholders or at any meeting of the Company stockholders called with respect to any of the matters specified in, and in accordance and consistent with, Section 3 of this Agreement. The Company agrees not to exercise the proxy granted herein for any purpose other than the purposes described in this Agreement. Except as otherwise provided for herein (including the next sentence), the Stockholder hereby affirms that

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the irrevocable proxy is coupled with an interest and may under no circumstances be revoked and that such irrevocable proxy is executed and intended to be irrevocable. Notwithstanding any other provisions of this Agreement, the irrevocable proxy granted hereunder shall automatically terminate upon the termination of this Agreement.

6. No Solicitation. Subject to Section 4, the Stockholder agrees not to, directly or indirectly, including through any of its officers, directors or agents, (a) solicit, seek or initiate or knowingly take any action to facilitate or encourage, any offers, inquiries or the making of any proposal or offer that constitutes, or could reasonably be expected to lead to, any Acquisition Proposal or Acquisition Inquiry or (b) enter into, continue or otherwise participate or engage in any discussions or negotiations regarding any Acquisition Proposal, or furnish to any person any non-public information or afford any person, other than Magenta or the Company, as applicable, access to such party’s property, books or records (except as required by applicable Law or pursuant to a request by a Governmental Authority) in connection with, any Acquisition Proposal; provided, however, that nothing in this Section 6 shall prevent the Stockholder from referring a person to this Section 6 or to the Merger Agreement.

7. Documentation and Information. The Stockholder shall permit and hereby authorizes Magenta and the Company to publish and disclose in all documents and schedules filed with the SEC, and any press release or other disclosure document that Magenta or the Company reasonably determines to be necessary in connection with the Merger and any of the Contemplated Transactions, a copy of this Agreement, the Stockholder’s identity and ownership of the Shares and the nature of the Stockholder’s commitments and obligations under this Agreement; provided, that, Magenta and the Company provide such documents, schedules, press release or other disclosure document to the Stockholder in advance for its review and comment. Each of Magenta and the Company is an intended third-party beneficiary of this Section 7.

8. No Exercise of Appraisal Rights; Waivers. The Stockholder hereby irrevocably and unconditionally (a) waives, and agrees to cause to be waived and to prevent the exercise of, any rights of appraisal, any dissenters’ rights and any similar rights (including any notice requirements related thereto) relating to the Merger that Stockholder may have by virtue of, or with respect to, any Shares (including all rights under Section 262 of the DGCL) and (b) agrees that the Stockholder will not bring, commence, institute, maintain, prosecute or voluntarily aid or participate in any action, claim, suit or cause of action, in law or in equity, in any court or before any Governmental Authority, which (i) challenges the validity of or seeks to enjoin the operation of any provision of this Agreement or (ii) alleges that the execution and delivery of this Agreement by the Stockholder breaches any duty that such Stockholder has (or may be alleged to have) to the Company or to the other Company stockholders; provided, that (x) the Stockholder may defend against, contest or settle any such action, claim, suit or cause of action brought against the Stockholder that relates solely to the Stockholder’s capacity as a director, officer or securityholder of the Company and (y) the foregoing shall not limit or restrict in any manner the Stockholder from enforcing the Stockholder’s rights under this Agreement and the other agreements entered into by the Stockholder in connection herewith, or otherwise in connection with the Merger, including the Stockholder’s right to receive the Merger Consideration pursuant to the terms of the Merger Agreement.

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9. Representations and Warranties of the Stockholder. The Stockholder hereby represents and warrants to the Company as follows:

(a) (i) The Stockholder is the beneficial owner of the shares of Company Capital Stock indicated in Appendix A (each of which shall be deemed to be “held” by the Stockholder for purposes of Section 3 unless otherwise expressly stated with respect to any shares in Appendix A), free and clear of any and all Encumbrances (except for any Encumbrance that may be imposed pursuant to this Agreement, the Voting Agreement, the Investors’ Rights Agreement of the Company, dated as of April 6, 2022 (the “Investors’ Rights Agreement”) or any lock-up agreement entered into by and between the Stockholder, the Company and Magenta); and (ii) the Stockholder does not beneficially own any securities of the Company other than the shares of Company Capital Stock and rights to purchase shares Company Capital Stock set forth in Appendix A.

(b) Except as otherwise provided in this Agreement, the Stockholder has full power and authority to (i) make, enter into and carry out the terms of this Agreement and (ii) vote all of its Shares in the manner set forth in this Agreement without the consent or approval of, or any other action on the part of, any other person or entity (including any Governmental Authority). Without limiting the generality of the foregoing, except for the Voting Agreement, the Stockholder has not entered into any voting agreement (other than this Agreement) with any person with respect to any of the Stockholder’s Shares, granted any person any proxy (revocable or irrevocable) or power of attorney with respect to any of the Stockholder’s Shares, deposited any of the Stockholder’s Shares in a voting trust or entered into any arrangement or agreement with any person limiting or affecting the Stockholder’s legal power, authority or right to vote the Stockholder’s Shares on any matter.

(c) This Agreement has been duly and validly executed and delivered by the Stockholder and (assuming the due authorization, execution and delivery by the other parties hereto) constitutes a valid and binding agreement of the Stockholder enforceable against the Stockholder in accordance with its terms, subject to the Enforceability Exceptions. The execution and delivery of this Agreement by the Stockholder and the performance by the Stockholder of the agreements and obligations hereunder will not result in any breach or violation of or be in conflict with or constitute a default under any term of any Contract or if applicable any provision of an organizational document (including a certificate of incorporation) to or by which the Stockholder is a party or bound, or any applicable law to which the Stockholder (or any of the Stockholder’s assets) is subject or bound, except for any such breach, violation, conflict or default which, individually or in the aggregate, would not reasonably be expected to materially impair or adversely affect the Stockholder’s ability to perform its obligations under this Agreement.

(d) The execution, delivery and performance of this Agreement by the Stockholder do not and will not require any consent, approval, authorization or permit of, action by, filing with or notification to, any Governmental Authority, except for any such consent, approval, authorization, permit, action, filing or notification the failure of which to make or obtain, individually or in the aggregate, has not and would not materially impair the Stockholder’s ability to perform its obligations under this Agreement.

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(e) The Stockholder has had the opportunity to review the Merger Agreement and this Agreement with counsel of the Stockholder’s own choosing. The Stockholder has had an opportunity to review with its own tax advisors the tax consequences of the Merger and the Contemplated Transactions. The Stockholder understands that it must rely solely on its advisors and not on any statements or representations made by Magenta, the Company or any of their respective agents or representatives with respect to the tax consequences of the Merger and the Contemplated Transactions. The Stockholder understands that such Stockholder (and not Magenta, the Company or the Surviving Corporation) shall be responsible for such Stockholder’s tax liability that may arise as a result of the Merger or the Contemplated Transactions. The Stockholder understands and acknowledges that the Company, Magenta and Merger Sub are entering into the Merger Agreement in reliance upon the Stockholder’s execution, delivery and performance of this Agreement.

(f) With respect to the Stockholder, as of the date hereof, there is no action, suit, investigation or proceeding pending against, or, to the knowledge of the Stockholder, threatened against, the Stockholder or any of the Stockholder’s properties or assets (including the Shares) that would reasonably be expected to prevent or materially delay or impair the ability of the Stockholder to perform its obligations hereunder or to consummate the transactions contemplated hereby.

10. Certain Agreements. Each Stockholder, by this Agreement, and with respect to such Stockholder’s Shares, severally and not jointly, hereby agrees to terminate, subject to the occurrence of, and effective immediately prior to, the Effective Time each of (a) the Voting Agreement, the Investors’ Rights Agreement and the Amended and Restated Right of First Refusal and Co-Sale Agreement, dated April 6, 2022, between the Company and the other parties thereto and (b) any rights under any letter agreement providing for redemption rights, put rights, purchase rights, information rights, rights to consult with and advise management, inspection rights, preemptive rights, board of directors observer rights or rights to receive information delivered to the board of directors or other similar rights not generally available to stockholders of the Company between the Stockholder and the Company, but excluding, for the avoidance of doubt, any rights the Stockholder may have that relate to any indemnification, commercial, development or employment agreements or arrangements between such Stockholder and the Company or any subsidiary of the Company, which shall survive in accordance with their terms. Each Stockholder hereby terminates and waives all rights of first refusal, redemption rights and rights of notice of the Merger and the other transactions contemplated by the Merger Agreement, effective as of immediately prior to, and contingent upon, the Effective Time.

11. Termination. This Agreement shall terminate and shall cease to be of any further force or effect as of the earliest of (a) such date and time as the Merger Agreement shall have been terminated pursuant to the terms thereof as in effect on the date of this Agreement (and without giving effect to any amendments thereto unless consented to by the Stockholder), (b) the Effective Time and (c) the time this Agreement is terminated upon the written agreement of the Stockholder, the Company and Magenta (the “Expiration Date”); provided, however, that (i) Section 12 shall survive the termination of this Agreement, and (ii) the termination of this Agreement shall not relieve any party hereto from any liability for any material and willful breach of this Agreement prior to the Effective Time.

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12. Miscellaneous Provisions.

(a) Amendments. No amendment of this Agreement shall be effective against any party unless it shall be in writing and signed by each of the parties hereto.

(b) Entire Agreement; Counterparts; Exchanges by Electronic Transmission or Facsimile. This Agreement constitutes the entire agreement between the parties to this Agreement and supersedes all other prior agreements, arrangements and understandings, both written and oral, among the parties with respect to the subject matter hereof. This Agreement may be executed in several counterparts, each of which shall be deemed an original and all of which shall constitute one and the same instrument. The exchange of a fully executed Agreement (in counterparts or otherwise) by all parties by facsimile or electronic transmission in PDF format shall be sufficient to bind the parties to the terms and conditions of this Agreement.

(c) Applicable Law; Jurisdiction. This Agreement shall be governed by, and construed in accordance with, the laws of the State of Delaware, regardless of the laws that might otherwise govern under applicable principles of conflicts of laws. In any action or proceeding between any of the parties arising out of or relating to this Agreement, each of the parties: (i) irrevocably and unconditionally consents and submits to the exclusive jurisdiction and venue of the Court of Chancery of the State of Delaware or, to the extent such court does not have subject matter jurisdiction, the Superior Court of the State of Delaware or the United States District Court for the District of Delaware, (ii) agrees that all claims in respect of such action or proceeding shall be heard and determined exclusively in accordance with clause (a) of this Section 12(c), (iii) waives any objection to laying venue in any such action or proceeding in such courts, (iv) waives any objection that such courts are an inconvenient forum or do not have jurisdiction over any party, (v) agrees that service of process upon such party in any such action or proceeding shall be effective if notice is given in accordance with Section 12(k) of this Agreement and (vi) irrevocably and unconditionally waives the right to trial by jury.

(d) Assignment. This Agreement shall be binding upon, and shall be enforceable by and inure solely to the benefit of, the parties and their respective successors and permitted assigns; provided, however, that neither this Agreement nor any of a party’s rights or obligations hereunder may be assigned or delegated by such party without the prior written consent of the other party (in whole or in part, whether by operation of law or otherwise), and any attempted or purported assignment or delegation of this Agreement or any of such rights or obligations by such party without the other party’s prior written consent shall be void and of no effect.

(e) No Third Party Rights. This Agreement is not intended to, and shall not, confer upon any other person any rights or remedies hereunder other than the parties hereto to the extent expressly set forth herein.

(f) Severability. Any term or provision of this Agreement that is invalid or unenforceable in any situation in any jurisdiction shall not affect the validity or enforceability of the remaining terms and provisions of this Agreement or the validity or enforceability of the offending term or provision in any other situation or in any other jurisdiction. If a final judgment of a court of competent jurisdiction declares that any term or provision of this Agreement is invalid or unenforceable, the Parties agree that the court making such determination shall have the power

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to limit such term or provision, to delete specific words or phrases or to replace such term or provision with a term or provision that is valid and enforceable and that comes closest to expressing the intention of the invalid or unenforceable term or provision, and this Agreement shall be valid and enforceable as so modified. In the event such court does not exercise the power granted to it in the prior sentence, the Parties agree to replace such invalid or unenforceable term or provision with a valid and enforceable term or provision that will achieve, to the extent possible, the economic, business and other purposes of such invalid or unenforceable term or provision.

(g) Specific Performance. Except as otherwise provided herein, any and all remedies herein expressly conferred upon a party will be deemed cumulative with and not exclusive of any other remedy conferred hereby, or by law or equity upon such party, and the exercise by a party of any one remedy will not preclude the exercise of any other remedy. The parties agree that irreparable damage for which monetary damages, even if available, would not be an adequate remedy, would occur in the event that any of the provisions of this Agreement were not performed in accordance with their specific terms (including failing to take such actions as are required of it hereunder to consummate this Agreement) or were otherwise breached. It is accordingly agreed that the parties shall be entitled to an injunction or injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions hereof in any court of the United States or any state having jurisdiction, this being in addition to any other remedy to which they are entitled at law or in equity, and each of the parties waives any bond, surety or other security that might be required of any other party with respect thereto. Each of the parties further agrees that it will not oppose the granting of an injunction, specific performance or other equitable relief on the basis that any other party has an adequate remedy at law or that any award of specific performance is not an appropriate remedy for any reason at law or in equity.

(h) Notices. All notices and other communications hereunder shall be in writing and shall be deemed duly delivered (i) one (1) Business Day after being sent for next Business Day delivery, fees prepaid, via a reputable international overnight courier service, (ii) upon delivery in the case of delivery by hand or (iii) on the date delivered in the place of delivery if sent by email or facsimile (with a written or electronic confirmation of delivery) prior to 6:00 p.m. (New York City time), otherwise on the next succeeding Business Day, (A) if to the Company or Magenta, to the address, electronic mail address or facsimile provided in the Merger Agreement, including to the persons designated therein to receive copies; and/or (B) if to the Stockholder, to the Stockholder’s address, electronic mail address or facsimile shown below Stockholder’s signature to this Agreement.

(i) Confidentiality. Except to the extent required by applicable Law or regulation, the Stockholder shall hold any non-public information regarding this Agreement, the Merger Agreement and the Merger in strict confidence and shall not divulge any such information to any third person until Magenta has publicly disclosed its entry into the Merger Agreement and this Agreement; provided, however, that the Stockholder may disclose such information to its Affiliates, partners, members, stockholders, parents, subsidiaries, attorneys, accountants, consultants, trustees, beneficiaries and other representatives (provided that such Persons are subject to confidentiality obligations at least as restrictive as those contained herein) or as otherwise permitted pursuant to and in accordance with the terms of Section 3.5 of the Investors’ Rights Agreement. Neither the Stockholder nor any of its Affiliates (other than Magenta, whose actions shall be governed by the Merger Agreement), shall issue or cause the publication of any

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press release or other public announcement with respect to this Agreement, the Merger, the Merger Agreement or the other transactions contemplated hereby or thereby without the prior written consent of the Company and Magenta, except as may be required by applicable Law in which circumstance such announcing party shall make reasonable efforts to consult with the Company and Magenta to the extent practicable. The Company is an intended third-party beneficiary of this Section 12(i).

(j) Interpretation. When reference is made in this Agreement to a Section or Appendix, such reference shall be to a Section of or Appendix to this Agreement, unless otherwise indicated. The headings contained in this Agreement are for convenience of reference only and shall not affect in any way the meaning or interpretation of this Agreement. The language used in this Agreement shall be deemed to be the language chosen by the parties hereto to express their mutual intent, and no rule of strict construction shall be applied against any party. Whenever the context may require, any pronouns used in this Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular form of nouns and pronouns shall include the plural, and vice versa. Any reference to any federal, state, local or foreign statute or law shall be deemed also to refer to all rules and regulations promulgated thereunder, unless the context requires otherwise. Whenever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation.”

[Remainder of Page Left Intentionally Blank]

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IN WITNESS WHEREOF, the undersigned have caused this Agreement to be duly executed as of the date first above written.

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Appendix A

Exhibit 10.2

FORM OF MAGENTA STOCKHOLDER SUPPORT AGREEMENT

This Support Agreement (this “Agreement”) is made and entered into as of May 2, 2023, by and among Dianthus Therapeutics, Inc., a Delaware corporation (the “Company”), Magenta Therapeutics, Inc., a Delaware corporation (“Magenta”), and the undersigned stockholder (the “Stockholder”) of Magenta. Capitalized terms used herein but not otherwise defined shall have the respective meanings ascribed to such terms in the Merger Agreement (as defined below).

RECITALS

WHEREAS, concurrently with the execution and delivery hereof, Magenta, the Company and Dio Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Magenta (the “Merger Sub”), have entered into an Agreement and Plan of Merger (as such agreement may be amended or supplemented from time to time pursuant to the terms thereof, the “Merger Agreement”), pursuant to which Merger Sub will merge with and into the Company, with the Company surviving the merger as the surviving corporation and a wholly owned subsidiary of Magenta (the “Merger”) upon the terms and subject to the conditions set forth in the Merger Agreement.

WHEREAS, as of the date hereof, the Stockholder is the beneficial owner (as defined in Rule 13d-1 under the Exchange Act) of such number of shares of Magenta Common Stock as indicated in Appendix A.

WHEREAS, as an inducement to the willingness of the Company to enter into the Merger Agreement, the Company has required that Stockholder enter into this Agreement.

NOW, THEREFORE, intending to be legally bound, the parties hereby agree as follows:

1. Certain Definitions. Capitalized terms used but not otherwise defined herein shall have the meanings ascribed thereto in the Merger Agreement. For all purposes of this Agreement, the following terms shall have the following respective meanings:

(a) “Constructive Sale” means, with respect to any security, a short sale with respect to such security, entering into or acquiring a derivative contract with respect to such security, entering into or acquiring a futures or forward contract to deliver such security or entering into any other hedging or other derivative transaction that has the effect of either directly or indirectly materially changing the economic benefits or risks of ownership of such security.

(b) “Magenta Stockholder Matters” means the approval of the Merger Agreement and the Contemplated Transactions, and, if deemed necessary by Magenta, an amendment to Magenta’s certificate of incorporation to effect the Nasdaq Reverse Split.

(c) “Shares” means (i) all shares of Magenta Common Stock owned, beneficially or of record, by the Stockholder as of the date hereof, and (ii) all additional shares of Magenta Common Stock acquired by the Stockholder, beneficially or of record, during the period commencing with the execution and delivery of this Agreement and expiring on the Closing Date.

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(d) “Transfer” or “Transferred” means, with respect to any security, the direct or indirect assignment, sale, transfer, tender, exchange, pledge or hypothecation, or the grant, creation or suffrage of a lien, security interest or encumbrance in or upon, or the gift, grant or placement in trust, or the Constructive Sale or other disposition of such security (including transfers by testamentary or intestate succession, by domestic relations order or other court order, or otherwise by operation of law) or any right, title or interest therein (including any right or power to vote to which the holder thereof may be entitled, whether such right or power is granted by proxy or otherwise), or the record or beneficial ownership thereof, the offer to make such a sale, transfer, Constructive Sale or other disposition, and each agreement, arrangement or understanding, whether or not in writing, to effect any of the foregoing.

2. Transfer and Voting Restrictions. The Stockholder covenants to the Company as follows:

(a) During the period commencing with the execution and delivery of this Agreement and expiring on the Expiration Date (as defined below), the Stockholder shall not Transfer any of the Stockholder’s Shares, or publicly announce its intention to Transfer any of its Shares.

(b) Except as otherwise permitted by this Agreement or by order of a court of competent jurisdiction, the Stockholder will not commit any act that would restrict the Stockholder’s legal power, authority and right to vote all of the Shares held by the Stockholder or otherwise prevent or disable the Stockholder from performing any of his, her or its obligations under this Agreement. Without limiting the generality of the foregoing, except for this Agreement and as otherwise permitted by this Agreement, the Stockholder shall not enter into any voting agreement with any person or entity with respect to any of the Stockholder’s Shares, grant any person or entity any proxy (revocable or irrevocable) or power of attorney with respect to any of the Shares, deposit any Shares in a voting trust or otherwise enter into any agreement or arrangement with any person or entity limiting or affecting the Stockholder’s legal power, authority or right to vote the Stockholder’s Shares in favor of the Magenta Stockholder Matters and against any competing proposals.

(c) Notwithstanding anything else herein to the contrary, the Stockholder may, at any time, Transfer Shares (i) by will or other testamentary document or by intestacy, (ii) to any investment fund or other entity controlled or managed by the Stockholder, (iii) to any member of the Stockholder’s immediate family or (iv) to any trust for the direct or indirect benefit of the Stockholder or the immediate family of the Stockholder or otherwise for estate planning purposes; provided, that (x) such Transferred Shares shall continue to be bound by this Agreement and (y) the applicable transferee shall have executed and delivered to Magenta and the Company a support agreement substantially identical to this Agreement upon consummation of the Transfer.

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3. Agreement to Vote Shares. The Stockholder covenants to the Company as follows:

(a) Until the Expiration Date (as defined below), at any meeting of the stockholders of Magenta, however called, and at every adjournment or postponement thereof, and on every action or approval by written consent of the stockholders of Magenta, the Stockholder shall be present (in person or by proxy) and vote, or exercise its right to consent with respect to, all Shares held by the Stockholder (A) in favor of the Magenta Stockholder Matters and (B) against any competing proposals.

(b) If the Stockholder is the beneficial owner, but not the record holder, of Shares, the Stockholder agrees to take all actions necessary to cause the record holder and any nominees to be present (in person or by proxy) and vote all the Stockholder’s Shares in accordance with this Section 3.

(c) In the event of a stock split, stock dividend or distribution, or any change in the capital stock of Magenta by reason of any split-up, reverse stock split, recapitalization, combination, reclassification, reincorporation, exchange of shares or the like, the term “Shares” shall be deemed to refer to and include such shares as well as all such stock dividends and distributions and any securities into which or for which any or all of such shares may be changed or exchanged or which are received in such transaction.

4. Action in Stockholder Capacity Only. The Stockholder is entering into this Agreement solely in the Stockholder’s capacity as a record holder and beneficial owner, as applicable, of its Shares and not in the Stockholder’s capacity as a director or officer of Magenta. Nothing herein shall limit or affect the Stockholder’s ability to act as an officer or director of Magenta.

5. Irrevocable Proxy. The Stockholder hereby revokes (or agrees to cause to be revoked) any proxies that the Stockholder has heretofore granted with respect to its Shares. In the event and to the extent that the Stockholder fails to vote the Shares in accordance with Section 3 at any applicable meeting of the stockholders of Magenta or pursuant to any applicable written consent of the stockholders of Magenta, the Stockholder shall be deemed to have irrevocably granted to, and appointed, the Company, and any individual designated in writing by the Company, and each of them individually, as his, her or its proxy and attorney-in-fact (with full power of substitution), for and in its name, place and stead, to vote his, her or its Shares in any action by written consent of Magenta stockholders or at any meeting of the Magenta stockholders called with respect to any of the matters specified in, and in accordance and consistent with, Section 3 of this Agreement. The Company agrees not to exercise the proxy granted herein for any purpose other than the purposes described in this Agreement. Except as otherwise provided for herein, the Stockholder hereby affirms that the irrevocable proxy is coupled with an interest and may under no circumstances be revoked and that such irrevocable proxy is executed and intended to be irrevocable. Notwithstanding any other provisions of this Agreement, the irrevocable proxy granted hereunder shall automatically terminate upon the termination of this Agreement.

6. No Solicitation. Subject to Section 4, the Stockholder agrees not to, directly or indirectly, including through any of its officers, directors or agents, (a) solicit, seek or initiate or knowingly take any action to facilitate or encourage, any offers, inquiries or the making of any proposal or offer that constitutes, or could reasonably be expected to lead to, any Acquisition Proposal or Acquisition Inquiry or (b) enter into, continue or otherwise participate or engage in any discussions or negotiations regarding any Acquisition Proposal, or furnish to any person any

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non-public information or afford any person, other than Magenta or the Company, as applicable, access to such party’s property, books or records (except pursuant to a request by a Governmental Authority) in connection with, any Acquisition Proposal; provided, however, that nothing in this Section 6 shall prevent the Stockholder from referring a person to this Section 6 or to the Merger Agreement.

7. Documentation and Information. The Stockholder shall permit and hereby authorizes Magenta and the Company to publish and disclose in all documents and schedules filed with the SEC, and any press release or other disclosure document that Magenta or the Company reasonably determines to be necessary in connection with the Merger and any of the Contemplated Transactions, a copy of this Agreement, the Stockholder’s identity and ownership of the Shares and the nature of the Stockholder’s commitments and obligations under this Agreement. Each of Magenta and the Company is an intended third-party beneficiary of this Section 7.

8. No Exercise of Appraisal Rights; Waivers. The Stockholder hereby irrevocably and unconditionally (a) waives, and agrees to cause to be waived and to prevent the exercise of, any rights of appraisal, any dissenters’ rights and any similar rights (including any notice requirements related thereto) relating to the Merger that Stockholder may have by virtue of, or with respect to, any Shares (including all rights under Section 262 of the DGCL) and (b) agrees that the Stockholder will not bring, commence, institute, maintain, prosecute or voluntarily aid or participate in any action, claim, suit or cause of action, in law or in equity, in any court or before any Governmental Authority, which (i) challenges the validity of or seeks to enjoin the operation of any provision of this Agreement or (ii) alleges that the execution and delivery of this Agreement by the Stockholder, or the approval of the Merger Agreement by the Magenta Board, breaches any fiduciary duty of the Magenta Board or any member thereof; provided, that the Stockholder may defend against, contest or settle any such action, claim, suit or cause of action brought against the Stockholder that relates solely to the Stockholder’s capacity as a director, officer or securityholder of Magenta.

9. Representations and Warranties of the Stockholder. The Stockholder hereby represents and warrants to the Company as follows:

(a) (i) The Stockholder is the beneficial or record owner of the shares of Magenta Common Stock indicated in Appendix A (each of which shall be deemed to be “held” by the Stockholder for purposes of Section 3 unless otherwise expressly stated with respect to any shares in Appendix A), free and clear of any and all Liens; and (ii) the Stockholder does not beneficially own any securities of Magenta other than the shares of Magenta Common Stock and rights to purchase shares Magenta Common Stock set forth in Appendix A.

(b) Except as otherwise provided in this Agreement, the Stockholder has full power and authority to (i) make, enter into and carry out the terms of this Agreement and (ii) vote all of its Shares in the manner set forth in this Agreement without the consent or approval of, or any other action on the part of, any other person or entity (including any Governmental Authority). Without limiting the generality of the foregoing, the Stockholder has not entered into any voting agreement (other than this Agreement) with any person with respect to any of the Stockholder’s Shares, granted any person any proxy (revocable or irrevocable) or power of attorney with respect to any of the Stockholder’s Shares, deposited any of the Stockholder’s Shares in a voting trust or entered into any arrangement or agreement with any person limiting or affecting the Stockholder’s legal power, authority or right to vote the Stockholder’s Shares on any matter.

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(c) This Agreement has been duly and validly executed and delivered by the Stockholder and (assuming the due authorization, execution and delivery by the other parties hereto) constitutes a valid and binding agreement of the Stockholder enforceable against the Stockholder in accordance with its terms, subject to the Enforceability Exceptions. The execution and delivery of this Agreement by the Stockholder and the performance by the Stockholder of the agreements and obligations hereunder will not result in any breach or violation of or be in conflict with or constitute a default under any term of any Contract or if applicable any provision of an organizational document (including a certificate of incorporation) to or by which the Stockholder is a party or bound, or any applicable law to which the Stockholder (or any of the Stockholder’s assets) is subject or bound, except for any such breach, violation, conflict or default which, individually or in the aggregate, would not reasonably be expected to materially impair or adversely affect the Stockholder’s ability to perform its obligations under this Agreement.

(d) The Stockholder has had the opportunity to review the Merger Agreement and this Agreement with the Stockholder’s legal counsel. The Stockholder understands and acknowledges that the Company is entering into the Merger Agreement in reliance upon the Stockholder’s execution, delivery and performance of this Agreement.

(e) The execution, delivery and performance of this Agreement by the Stockholder do not and will not require any consent, approval, authorization or permit of, action by, filing with or notification to, any Governmental Authority, except for any such consent, approval, authorization, permit, action, filing or notification the failure of which to make or obtain, individually or in the aggregate, has not and would not materially impair the Stockholder’s ability to perform its obligations under this Agreement.

(f) The Stockholder has had the opportunity to review the Merger Agreement and this Agreement with counsel of the Stockholder’s own choosing. The Stockholder has had an opportunity to review with its own tax advisors the tax consequences of the Merger and the Contemplated Transactions. The Stockholder understands that it must rely solely on its advisors and not on any statements or representations made by Magenta, the Company or any of their respective agents or representatives with respect to the tax consequences of the Merger and the Contemplated Transactions. The Stockholder understands that such Stockholder (and not Magenta, the Company or the Surviving Corporation) shall be responsible for such Stockholder’s tax liability that may arise as a result of the Merger or the Contemplated Transactions. The Stockholder understands and acknowledges that the Company, Magenta and Merger Sub are entering into the Merger Agreement in reliance upon the Stockholder’s execution, delivery and performance of this Agreement.

(g) With respect to the Stockholder, as of the date hereof, there is no action, suit, investigation or proceeding pending against, or, to the knowledge of the Stockholder, threatened against, the Stockholder or any of the Stockholder’s properties or assets (including the Shares) that would reasonably be expected to prevent or materially delay or impair the ability of the Stockholder to perform its obligations hereunder or to consummate the transactions contemplated hereby.

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10. Termination. This Agreement shall terminate and shall cease to be of any further force or effect as of the earlier of (a) such date and time as the Merger Agreement shall have been terminated pursuant to the terms thereof or (b) the Effective Time (the “Expiration Date”); provided, however, that (i) Section 11 shall survive the termination of this Agreement, and (ii) the termination of this Agreement shall not relieve any party hereto from any liability for any material and willful breach of this Agreement prior to the Effective Time.

11. Miscellaneous Provisions.

(a) Amendments. No amendment of this Agreement shall be effective against any party unless it shall be in writing and signed by each of the parties hereto.

(b) Entire Agreement; Counterparts; Exchanges by Electronic Transmission or Facsimile. This Agreement constitutes the entire agreement between the parties to this Agreement and supersedes all other prior agreements, arrangements and understandings, both written and oral, among the parties with respect to the subject matter hereof. This Agreement may be executed in several counterparts, each of which shall be deemed an original and all of which shall constitute one and the same instrument. The exchange of a fully executed Agreement (in counterparts or otherwise) by all parties by facsimile or electronic transmission in PDF format shall be sufficient to bind the parties to the terms and conditions of this Agreement.

(c) Applicable Law; Jurisdiction. This Agreement shall be governed by, and construed in accordance with, the laws of the State of Delaware, regardless of the laws that might otherwise govern under applicable principles of conflicts of laws. In any action or proceeding between any of the parties arising out of or relating to this Agreement, each of the parties: (i) irrevocably and unconditionally consents and submits to the exclusive jurisdiction and venue of the Court of Chancery of the State of Delaware or, to the extent such court does not have subject matter jurisdiction, the Superior Court of the State of Delaware or the United States District Court for the District of Delaware, (ii) agrees that all claims in respect of such action or proceeding shall be heard and determined exclusively in accordance with clause (a) of this Section 11(c), (iii) waives any objection to laying venue in any such action or proceeding in such courts, (iv) waives any objection that such courts are an inconvenient forum or do not have jurisdiction over any party, (v) agrees that service of process upon such party in any such action or proceeding shall be effective if notice is given in accordance with Section 11(k) of this Agreement and (vi) irrevocably and unconditionally waives the right to trial by jury.

(d) Assignment. This Agreement shall be binding upon, and shall be enforceable by and inure solely to the benefit of, the parties and their respective successors and permitted assigns; provided, however, that neither this Agreement nor any of a party’s rights or obligations hereunder may be assigned or delegated by such party without the prior written consent of the other party, and any attempted assignment or delegation of this Agreement or any of such rights or obligations by such party without the other party’s prior written consent shall be void and of no effect. Any purported assignment of rights or delegation of performance obligations in violation of this Section 11(d) is void.

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(e) No Third Party Rights. This Agreement is not intended to, and shall not, confer upon any other person any rights or remedies hereunder other than the parties hereto to the extent expressly set forth herein.

(f) Severability. Any term or provision of this Agreement that is invalid or unenforceable in any situation in any jurisdiction shall not affect the validity or enforceability of the remaining terms and provisions of this Agreement or the validity or enforceability of the offending term or provision in any other situation or in any other jurisdiction. If a final judgment of a court of competent jurisdiction declares that any term or provision of this Agreement is invalid or unenforceable, the Parties agree that the court making such determination shall have the power to limit such term or provision, to delete specific words or phrases or to replace such term or provision with a term or provision that is valid and enforceable and that comes closest to expressing the intention of the invalid or unenforceable term or provision, and this Agreement shall be valid and enforceable as so modified. In the event such court does not exercise the power granted to it in the prior sentence, the Parties agree to replace such invalid or unenforceable term or provision with a valid and enforceable term or provision that will achieve, to the extent possible, the economic, business and other purposes of such invalid or unenforceable term or provision.

(g) Specific Performance. Except as otherwise provided herein, any and all remedies herein expressly conferred upon a party will be deemed cumulative with and not exclusive of any other remedy conferred hereby, or by law or equity upon such party, and the exercise by a party of any one remedy will not preclude the exercise of any other remedy. The parties agree that irreparable damage for which monetary damages, even if available, would not be an adequate remedy, would occur in the event that any of the provisions of this Agreement were not performed in accordance with their specific terms (including failing to take such actions as are required of it hereunder to consummate this Agreement) or were otherwise breached. It is accordingly agreed that the parties shall be entitled to an injunction or injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions hereof in any court of the United States or any state having jurisdiction, this being in addition to any other remedy to which they are entitled at law or in equity, and each of the parties waives any bond, surety or other security that might be required of any other party with respect thereto. Each of the parties further agrees that it will not oppose the granting of an injunction, specific performance or other equitable relief on the basis that any other party has an adequate remedy at law or that any award of specific performance is not an appropriate remedy for any reason at law or in equity.

(h) Notices. All notices and other communications hereunder shall be in writing and shall be deemed duly delivered (i) one (1) Business Day after being sent for next Business Day delivery, fees prepaid, via a reputable international overnight courier service, (ii) upon delivery in the case of delivery by hand or (iii) on the date delivered in the place of delivery if sent by email or facsimile (with a written or electronic confirmation of delivery) prior to 6:00 p.m. (New York City time), otherwise on the next succeeding Business Day, (A) if to the Company or Magenta, to the address, electronic mail address or facsimile provided in the Merger Agreement, including to the persons designated therein to receive copies; and/or (B) if to the Stockholder, to the Stockholder’s address, electronic mail address or facsimile shown below Stockholder’s signature to this Agreement.

Page 7

(i) Confidentiality. Except to the extent required by applicable Law or regulation, the Stockholder shall hold any non-public information regarding this Agreement, the Merger Agreement and the Merger in strict confidence and shall not divulge any such information to any third person until Magenta has publicly disclosed its entry into the Merger Agreement and this Agreement; provided, however, that the Stockholder may disclose such information to its Affiliates, partners, members, stockholders, parents, subsidiaries, attorneys, accountants, consultants, trustees, beneficiaries and other representatives (provided that such Persons are subject to confidentiality obligations at least as restrictive as those contained herein). Neither the Stockholder nor any of its Affiliates (other than Magenta, whose actions shall be governed by the Merger Agreement), shall issue or cause the publication of any press release or other public announcement with respect to this Agreement, the Merger, the Merger Agreement or the other transactions contemplated hereby or thereby without the prior written consent of the Company and Magenta, except as may be required by applicable Law in which circumstance such announcing party shall make reasonable efforts to consult with the Company and Magenta to the extent practicable. The Company is an intended third-party beneficiary of this Section 11(i).

(j) Interpretation. When reference is made in this Agreement to a Section or Appendix, such reference shall be to a Section of or Appendix to this Agreement, unless otherwise indicated. The headings contained in this Agreement are for convenience of reference only and shall not affect in any way the meaning or interpretation of this Agreement. The language used in this Agreement shall be deemed to be the language chosen by the parties hereto to express their mutual intent, and no rule of strict construction shall be applied against any party. Whenever the context may require, any pronouns used in this Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular form of nouns and pronouns shall include the plural, and vice versa. Any reference to any federal, state, local or foreign statute or law shall be deemed also to refer to all rules and regulations promulgated thereunder, unless the context requires otherwise. Whenever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation.”

[Remainder of Page Left Intentionally Blank]

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IN WITNESS WHEREOF, the undersigned have caused this Agreement to be duly executed as of the date first above written.

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Appendix A

Exhibit 10.3

FORM OF LOCK-UP AGREEMENT

May 2, 2023

Magenta Therapeutics, Inc.

300 Technology Square, 8th Floor

Cambridge, Massachusetts 02139

Ladies and Gentlemen:

The undersigned signatory of this lock-up agreement (this “Lock-Up Agreement”) understands that Magenta Therapeutics, Inc., a Delaware corporation (“Magenta”), has entered into an Agreement and Plan of Merger, dated as of May 2, 2023 (as the same may be amended from time to time, the “Merger Agreement”) with Dio Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Magenta, and Dianthus Therapeutics, Inc., a Delaware corporation (the “Company”). Capitalized terms used but not otherwise defined herein shall have the respective meanings ascribed to such terms in the Merger Agreement.

As a condition and inducement to Magenta to enter into the Merger Agreement and to consummate the transactions contemplated thereby, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the undersigned hereby irrevocably agrees that, subject to the exceptions set forth herein, without the prior written consent of Magenta, the undersigned will not, during the period commencing upon the Closing and ending on the date that is 180 days after the Closing Date (the “Restricted Period”):

(1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, or otherwise transfer or dispose of, directly or indirectly, any shares of Magenta Common Stock or any securities convertible into or exercisable or exchangeable for shares of Magenta Common Stock (including without limitation, shares of Magenta Common Stock or such other securities which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations of the SEC and securities of Mammoth which may be issued upon exercise of an option to purchase shares of Magenta Common Stock or a warrant to purchase shares of Magenta Common Stock) that are currently or hereafter owned by the undersigned, except as set forth below (collectively, the “Undersigned’s Shares”);

(2) enter into any swap, short sale, hedge or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of the Undersigned’s Shares regardless of whether any such transaction described in clause (1) above or this clause (2) is to be settled by delivery of shares of Magenta Common Stock or other securities, in cash or otherwise;

(3) make any demand for, or exercise any right with respect to, the registration of any shares of Magenta Common Stock or any security convertible into or exercisable or exchangeable for shares of Magenta Common Stock (other than such rights set forth in the Merger Agreement); or

(4) publicly disclose the intention to do any of the foregoing.

The restrictions and obligations contemplated by this Lock-Up Agreement shall not apply to:

(a) transfers of the Undersigned’s Shares:

(1) (A) to any person related to the undersigned (or to an ultimate beneficial owner of the undersigned) by blood or adoption who is an immediate family member of the undersigned, or by marriage or domestic partnership (a “Family Member”), or to a trust formed for the benefit of the undersigned or any of the undersigned’s Family Members, (B) to the undersigned’s estate, following the death of the undersigned, by will, intestacy or other operation of Law, (C) as a bona fide gift or a charitable contribution, (D) by operation of Law pursuant to a qualified domestic order or in connection with a divorce settlement or (E) to any partnership, corporation or limited liability company which is controlled by or under common control with the undersigned and/or by any such Family Member(s);

(2) if the undersigned is a corporation, partnership, limited liability company or other entity, (A) to another corporation, partnership, limited liability company or other entity that is a direct or indirect affiliate (as defined under Rule 12b-2 of the Exchange Act) of the undersigned, including investment funds or other entities that controls or manages, is under common control or management with, or is controlled or managed by, the undersigned, (B) as a distribution or dividend to equity holders, current or former general or limited partners, members or managers (or to the estates of any of the foregoing), as applicable, of the undersigned (including upon the liquidation and dissolution of the undersigned pursuant to a plan of liquidation approved by the undersigned’s equity holders), (C) as a bona fide gift or a charitable contribution or otherwise to a trust or other entity for the direct or indirect benefit of an immediate family member of a beneficial owner (as defined in Rule 13d-3 of the Exchange Act) of the Undersigned’s Shares or (D) transfers or dispositions not involving a change in beneficial ownership; or

(3) if the undersigned is a trust, to any grantors or beneficiaries of the trust;

provided that, in the case of any transfer or distribution pursuant to this clause (a), such transfer is not for value (other than transfers pursuant to 1(A), 1(E) or 2(A)) and each donee, heir, beneficiary or other transferee or distributee shall sign and deliver to Magenta a lock-up agreement in the form of this Lock-Up Agreement with respect to the shares of Magenta Common Stock or such other securities that have been so transferred or distributed;

(b) the exercise of an option to purchase shares of Magenta Common Stock (including a net or cashless exercise of an option to purchase shares of Magenta Common Stock ), and any related transfer of shares of Magenta Common Stock to Magenta for the purpose of paying the exercise price of such options or for paying taxes (including estimated taxes) due as a result of the exercise of such options or for paying taxes (including estimated taxes) due as a result of the exercise of such options; provided that, for the avoidance of doubt, the underlying shares of Magenta Common Stock shall continue to be subject to the restrictions on transfer set forth in this Lock-Up Agreement;

(c) transfers to Magenta in connection with the net settlement of any other equity award that represents the right to receive in the future shares of Magenta Common Stock, settled in shares of Magenta Common Stock, to pay any tax withholding obligations; provided that, for the avoidance of doubt, the underlying shares of Magenta Common Stock shall continue to be subject to the restrictions on transfer set forth in this Lock-Up Agreement;

(d) the establishment of a trading plan pursuant to Rule 10b5-1 under the Exchange Act for the transfer of shares of Magenta Common Stock; provided that such plan does not provide for any transfers of shares of Magenta Common Stock during the Restricted Period;

(e) transfers by the undersigned of shares of Magenta Common Stock purchased by the undersigned on the open market or in a public offering by Mammoth, in each case following the Effective Time;

(f) pursuant to a bona-fide third party tender offer, merger, consolidation or other similar transaction made to all holders of Magenta’s capital stock involving a change of control of Magenta, provided that in the event that such tender offer, merger, consolidation or other such transaction is not completed, the Undersigned’s Shares shall remain subject to the restrictions contained in this Lock-Up Agreement;

(g) pursuant to an order of a court or regulatory agency; or

(h) transfers by the undersigned of shares of Magenta Common Stock issued pursuant to the Merger Agreement in respect of shares of the Company, if any, purchased from the Company on or about the Closing Date but prior to the Closing.

and provided, further, that, with respect to each of (b), (c), and (d) above, no filing by any party (including any donor, donee, transferor, transferee, distributor or distributee) under Section 16 of the Exchange Act or other public announcement shall be made voluntarily reporting a reduction in beneficial ownership of shares of Magenta Common Stock or any securities convertible into or exercisable or exchangeable for Magenta Common Stock in connection with such transfer or disposition during the Restricted Period (other than any exit filings) and if any filings under Section 16(a) of the Exchange Act, or other public filing, report or announcement reporting a reduction in beneficial ownership of shares of Magenta Common Stock in connection with such transfer or distribution, shall be legally required during the Restricted Period, such filing, report or announcement shall clearly indicate in the footnotes therein, in reasonable detail, a description of the circumstances of the transfer and that the shares remain subject to the lock-up agreement.

For purposes of this Lock-Up Agreement, “change of control” shall mean the transfer (whether by tender offer, merger, consolidation or other similar transaction), in one transaction or a series of related transactions, to a person or group of affiliated persons, of the Company’s voting securities if, after such transfer, the Company’s stockholders as of immediately prior to such transfer do not hold a majority of the outstanding voting securities of the Company (or the surviving entity).

Any attempted transfer in violation of this Lock-Up Agreement will be of no effect and null and void, regardless of whether the purported transferee has any actual or constructive knowledge of the transfer restrictions set forth in this Lock-Up Agreement, and will not be recorded on the share register of Magenta. In furtherance of the foregoing, the undersigned agrees that Magentaand any duly appointed transfer agent for the registration or transfer of the securities

described herein are hereby authorized to decline to make any transfer of securities if such transfer would constitute a violation or breach of this Lock-Up Agreement. Magenta may cause the legend set forth below, or a legend substantially equivalent thereto, to be placed upon any certificate(s) or other documents, ledgers or instruments evidencing the undersigned’s ownership of Magenta Common Stock:

THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO AND MAY ONLY BE TRANSFERRED IN COMPLIANCE WITH A LOCK-UP AGREEMENT, A COPY OF WHICH IS ON FILE AT THE PRINCIPAL OFFICE OF THE COMPANY.

The undersigned hereby represents and warrants that the undersigned has full power and authority to enter into this Lock-Up Agreement. All authority herein conferred or agreed to be conferred and any obligations of the undersigned shall be binding upon the successors, assigns, heirs or personal representatives of the undersigned.

The undersigned understands that if the Merger Agreement is terminated for any reason, the undersigned shall be released from all obligations under this Lock-Up Agreement. The undersigned understands that Magenta is proceeding with the transactions contemplated by the Merger Agreement in reliance upon this Lock-Up Agreement.

Except as otherwise provided herein, any and all remedies herein expressly conferred upon a party will be deemed cumulative with and not exclusive of any other remedy conferred hereby, or by law or equity upon such party, and the exercise by a party of any one remedy will not preclude the exercise of any other remedy. The parties agree that irreparable damage for which monetary damages, even if available, would not be an adequate remedy, would occur in the event that any of the provisions of this Lock-Up Agreement were not performed in accordance with their specific terms (including failing to take such actions as are required of it hereunder to consummate this Agreement) or were otherwise breached. It is accordingly agreed that the parties shall be entitled to an injunction or injunctions to prevent breaches of this Lock-Up Agreement and to enforce specifically the terms and provisions hereof in any court of the United States or any state having jurisdiction, this being in addition to any other remedy to which they are entitled at law or in equity, and each of the parties waives any bond, surety or other security that might be required of any other party with respect thereto. Each of the parties further agrees that it will not oppose the granting of an injunction, specific performance or other equitable relief on the basis that any other party has an adequate remedy at law or that any award of specific performance is not an appropriate remedy for any reason at law or in equity.

In the event that any holder of Magenta’s securities that are subject to a substantially similar agreement entered into by such holder, other than the undersigned, is permitted by Magenta to sell or otherwise transfer or dispose of shares of Magenta Common Stock for value other than as permitted by this or a substantially similar agreement entered into by such holder (whether in one or multiple releases or waivers), the same percentage of shares of Magenta Common Stock held by the undersigned on the date of such release or waiver as the percentage of the total number of outstanding shares of Magenta Common Stock held by such holder on the date of such release or waiver that are the subject of such release or waiver shall be immediately and fully released on

the same terms from any remaining restrictions set forth herein (the “Pro-Rata Release”); provided, however, that such Pro-Rata Release shall not be applied unless and until permission has been granted by Magenta to an equity holder or equity holders to sell or otherwise transfer or dispose of all or a portion of such equity holders shares of Magenta Common Stock in an aggregate amount in excess of 1% of the number of shares of Magenta Common Stock subject to a substantially similar agreement. In the event of any Pro-Rata Release, the Company shall promptly (and in any event within two (2) business days of such release) inform each relevant holder of Magenta Common Stock of the terms of such Pro-Rata Release.

Upon the release of any of the Undersigned’s Shares from this Lock-Up Agreement, Magenta will reasonably cooperate with the undersigned to facilitate the timely preparation and delivery of certificates representing the Undersigned Shares without the restrictive legend above or the withdrawal of any stop transfer instructions by virtue of this Lock-Up Agreement.

This Lock-Up Agreement shall be governed by, and construed in accordance with, the laws of the State of Delaware, regardless of the laws that might otherwise govern under applicable principles of conflicts of laws. In any action or proceeding between any of the parties arising out of or relating to this Lock-Up Agreement, each of the parties: (i) irrevocably and unconditionally consents and submits to the exclusive jurisdiction and venue of the Court of Chancery of the State of Delaware or, to the extent such court does not have subject matter jurisdiction, the Superior Court of the State of Delaware or the United States District Court for the District of Delaware, (ii) agrees that all claims in respect of such action or proceeding shall be heard and determined exclusively in accordance with foregoing clause (i) of this paragraph, (iii) waives any objection to laying venue in any such action or proceeding in such courts, (iv) waives any objection that such courts are an inconvenient forum or do not have jurisdiction over any party and (v) irrevocably and unconditionally waives the right to trial by jury. This Lock-Up Agreement constitutes the entire agreement between the parties to this Lock-Up Agreement and supersedes all other prior agreements, arrangements and understandings, both written and oral, among the parties with respect to the subject matter hereof. This Lock-Up Agreement may be executed in several counterparts, each of which shall be deemed an original and all of which shall constitute one and the same instrument. The exchange of a fully executed Lock-Up Agreement (in counterparts or otherwise) by all parties by facsimile or electronic transmission in PDF format shall be sufficient to bind the parties to the terms and conditions of this Agreement.

[SIGNATURE PAGE FOLLOWS]

Print Name of Stockholder:

[Signature Page to Lock-Up Agreement]

[Signature Page to Lock-Up Agreement]

Exhibit 10.4

FORM OF CONTINGENT VALUE RIGHTS AGREEMENT

THIS CONTINGENT VALUE RIGHTS AGREEMENT (this “Agreement”), dated as of [__], 2023, is entered into by and among Magenta Therapeutics, Inc., a Delaware corporation (the “Company”) and Computershare Inc., a Delaware corporation (“Computershare”), and its wholly-owned subsidiary, Computershare Trust Company, N.A., a federally chartered trust company (collectively, as “Rights Agent”).

RECITALS

WHEREAS, the Company, Dio Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of the Company (“Merger Sub”), and Dianthus Therapeutics, Inc., a Delaware corporation (“Dianthus”), have entered into an Agreement and Plan of Merger, dated as of May 2, 2023 (the “Merger Agreement”), pursuant to which Merger Sub will merge with and into Dianthus, with Dianthus surviving the Merger as a wholly-owned subsidiary of Magenta;

WHEREAS, pursuant to the Merger Agreement, and in accordance with the terms and conditions thereof, the Company has agreed to provide to the Holders (as defined herein) contingent value rights as hereinafter described;

WHEREAS, the parties have done all things reasonably necessary to make the contingent value rights, when issued pursuant to the Merger Agreement and hereunder, the valid obligations of the Company and to make this Agreement a valid and binding agreement of the Company, in accordance with its terms; and

NOW, THEREFORE, in consideration of the premises and the consummation of the transactions referred to above, it is mutually covenanted and agreed, for the proportionate benefit of all Holders, as follows:

ARTICLE 1

DEFINITIONS

Section 1.1 Definitions. Capitalized terms used but not otherwise defined herein have the meanings ascribed thereto in the Merger Agreement. The following terms have the meanings ascribed to them as follows:

“Acting Holders” means, at the time of determination, the Holders of more than 30% of the outstanding CVRs, as reflected on the CVR Register.

“Assignee” has the meaning set forth in Section 7.5.

“Calendar Quarter” means the successive periods of three (3) consecutive calendar months ending on March 31, June 30, September 30 or December 31, for so long as this Agreement is in effect; provided, however that (a) the first Calendar Quarter shall commence on the date of this Agreement and shall end on the first September 30 thereafter, and (b) the last Calendar Quarter shall commence on the first day after the full Calendar Quarter immediately preceding the effective date of the termination or expiration of this Agreement and shall end on the effective date of the termination or expiration of this Agreement.

“Common Stock” means the common stock, $0.001 par value, of the Company.

“CVR” means a contingent contractual right of Holders to receive CVR Payments pursuant to the Merger Agreement and this Agreement.

“CVR Payment” means a cash payment equal to the Net Proceeds received by the Company in a given Calendar Quarter ending on or after [•]; provided, that the Company, in its reasonable discretion as resolved by the Company’s Board of Directors, may withhold up to 20% of any CVR Payment to provide for the satisfaction of (i) indemnity obligations under any Disposition Agreement in excess of any escrow fund established therein, in each case to the extent not already deducted as Permitted Deductions and (ii) any

Loss arising out of any third-party claims, demands, actions, or other proceedings relating to or in connection with any Potentially Transferable Assets during the CVR Term; provided, further, that any such withheld Net Proceeds shall be distributed (net of any Permitted Deductions satisfied therefrom) to the Holders no later than three (3) years following the date such Net Proceeds would have otherwise been distributed to the Holders in the CVR Payment from which such Net Proceeds were otherwise deducted; provided, further, that, such withholding shall not be permitted if (x) the applicable indemnification period under the applicable Disposition Agreement related to such CVR Payment has expired by its terms when the CVR Payment is received or (y) the maximum aggregate liability in respect of the applicable indemnification obligations has been held back or setoff (including any amounts deposited in escrow) by the purchaser or acquiror under the applicable Disposition Agreement.

“CVR Payment Amount” means with respect to each CVR Payment and each Holder, an amount equal to such CVR Payment divided by the total number of CVRs and then multiplied by the total number of CVRs held by such Holder as reflected on the CVR Register.

“CVR Payment Period” means a period equal to a Calendar Quarter ending at any time after the effective date of a Disposition Agreement.

“CVR Payment Statement” means, for a given CVR Payment Period during the CVR Term, a written statement of the Company, signed on behalf of the Company, setting forth in reasonable detail the calculation of the applicable CVR Payment for such CVR Payment Period.

“CVR Register” has the meaning set forth in Section 2.3(b).

“CVR Term” means the period beginning on the Closing and ending upon the third anniversary of this Agreement; provided that, with respect to any Disposition Agreement set forth on Schedule 1.1, the CVR Term shall extent until the latest date that the Company may earn a contingent, earnout, milestone or similar payment pursuant to such Disposition Agreement.

“Disposition” means the sale, license, transfer or disposition of any Potentially Transferable Asset (including any such sale or disposition of equity securities in any Subsidiary established by the Company to hold any right, title or interest in or to any Potentially Transferable Asset).

“Disposition Agreement” means a definitive written agreement providing for a transaction or series of transactions between the Company or its Affiliates and any Person who is not an Affiliate of the Company regarding a Disposition, in each case, as set forth on Schedule 1.1 hereto or entered into during the period beginning on the Closing Date and ending December 31, 2023.

“Disposition Period” means the period beginning on the execution date of the Merger Agreement and ending on December 31, 2023.

“Gross Proceeds” means, without duplication, the sum of all cash consideration actually received by the Company or its Affiliates during the CVR Term in consideration for a Disposition pursuant to a Disposition Agreement.

“Holder” means, at the relevant time, a Person in whose name CVRs are registered in the CVR Register.

“Loss” has the meaning set forth in Section 3.2(g).

“Net Proceeds” means, for any CVR Payment Period, Gross Proceeds minus Permitted Deductions, all as calculated, to the extent in accordance with GAAP, in a manner consistent with the Company’s accounting practices and the most recently filed annual audited financial statements with the SEC, except as otherwise set forth herein. For clarity, to the extent Permitted Deductions exceed Gross Proceeds for any CVR Payment Period, any excess Permitted Deductions shall be applied against Gross Proceeds in subsequent CVR Payment Periods.

“Notice” has the meaning set forth in Section 7.1.

“Officer’s Certificate” means a certificate signed by the chief executive officer and the chief financial officer of the Company, in their respective official capacities.

“Party” means the Company or the Rights Agent.

“Permitted Deductions” means the sum of:

(a) any applicable Tax (including any applicable value added or sales taxes) imposed on Gross Proceeds and payable by the Company or any of its Affiliates (regardless of whether the due date for such Taxes arises during or after the Disposition Period) and, without duplication, any income or other similar Taxes payable by the Company or any of its Affiliates that would not have been incurred by the Company or any of its Affiliates but for the Gross Proceeds; provided that, for purposes of calculating income Taxes incurred by the Company or its Affiliates in respect of the Gross Proceeds, any such income Taxes shall be computed based on the gain recognized by the Company or its Affiliates from the Disposition after reduction for any net operating loss carryforwards or other Tax attributes of the Company or its Affiliates as of the Closing Date that are available to offset such gain after taking into account any limits of the usability of such attributes, including under Section 382 of the Code as determined by the Company’s tax advisers (and for the sake of clarity such income taxes shall be calculated without taking into account any net operating losses or other tax attributes generated by the Company or its Affiliates after the Closing Dates);

(b) any expenses incurred by the Company or any of its Affiliates in respect of its performance of this Agreement following the Closing Date or in respect of its performance of any Contract in connection with any Potentially Transferable Asset, including any costs related to the prosecution, maintenance or enforcement by the Company or any of its Subsidiaries of intellectual property rights (but excluding any costs related to a breach of this Agreement, including costs incurred in litigation in respect of the same);

(c) any expenses incurred or accrued by the Company or any of its Affiliates in connection with the negotiation, entry into and closing of any Disposition of any Potentially Transferable Asset, including any brokerage fee, finder’s fee, opinion fee, success fee, transaction fee, service fee or other fee, commission or expense owed to any broker, finder, investment bank, auditor, accountant, counsel, advisor or other third party in relation thereto;

(d) any Losses incurred or reasonably expected to be incurred by the Company or any of its Affiliates arising out of any third-party claims, demands, actions, or other proceedings relating to or in connection with any Disposition, including indemnification obligations of the Company or any of its Affiliates set forth in any Disposition Agreement;

(e) any proceeds in consideration for a Disposition pursuant to a Disposition Agreement included in the final determination of Magenta Net Cash in accordance with the Merger Agreement;

(f) any Liabilities borne by the Company or any of its Affiliates pursuant to Contracts related to Potentially Transferable Assets, including costs arising from the termination thereof; and

(g) any Liabilities existing or incurred during the CVR Term that would have been required to be included in the calculation of Magenta Net Cash to the extent not taken account in the calculation of Magenta Net Cash.

“Permitted Transfer” means a transfer of CVRs (a) upon death of a Holder by will or intestacy; (b) pursuant to a court order; (c) by operation of law (including by consolidation or merger) or without consideration in connection with the dissolution, liquidation or termination of any corporation, limited liability company, partnership or other entity; (d) in the case of CVRs held in book-entry or other similar nominee form, from a nominee to a beneficial owner and, if applicable, through an intermediary, to the extent allowable by DTC; or (e) as provided in Section 2.6.

“Potentially Transferable Assets” means the tangible and intangible assets primarily used in or primarily related to the Company’s MGTA-145 program, CD45-ADC program, MGTA-117 antibody, the E478 technology or the Igenica patent portfolio.

“Rights Agent” means the Rights Agent named in the first paragraph of this Agreement, until a successor Rights Agent will have become the Rights Agent pursuant to the applicable provisions of this Agreement, and thereafter “Rights Agent” will mean such successor Rights Agent.

ARTICLE 2

CONTINGENT VALUE RIGHTS

Section 2.1 Holders of CVRs; Appointment of Rights Agent.

(a) The CVRs represent the rights of Holders to receive CVR Payments pursuant to this Agreement. The initial Holders will be the holders of Magenta Common Stock as of immediately prior to the Effective Time. One CVR will be issued with respect to each share of Common Stock that is outstanding as of immediately prior to the Effective Time (including, for the avoidance of doubt, those shares of Common Stock issued upon settlement of Magenta Restricted Stock Units pursuant to Section 6.7 of the Merger Agreement).

(b) The Company hereby appoints the Rights Agent to act as Rights Agent for the Company in accordance with the express terms and conditions set forth in this Agreement, and the Rights Agent hereby accepts such appointment.

Section 2.2 Non-transferable. The CVRs may not be sold, assigned, transferred, pledged, encumbered or in any other manner transferred or disposed of, in whole or in part, other than through a Permitted Transfer. The CVRs will not be listed on any quotation system or traded on any securities exchange.

Section 2.3 No Certificate; Registration; Registration of Transfer; Change of Address.

(a) The CVRs will be issued in book-entry form only and will not be evidenced by a certificate or other instrument.

(b) The Rights Agent shall create and maintain a register (the “CVR Register”) for the purpose of registering CVRs and Permitted Transfers. The CVR Register will be created, and CVRs will be distributed, pursuant to written instructions to the Rights Agent from the Company. The CVR Register will initially show one position for Cede & Co. representing shares of Common Stock held by DTC on behalf of the street holders of the shares of Common Stock held by such holders as of immediately prior to the Effective Time. The Rights Agent will have no responsibility whatsoever directly or indirectly to the street name holders with respect to transfers of CVRs. With respect to any payments or issuances to be made under Section 2.4 below, the Rights Agent will accomplish the payment to any former street name holders of shares Common Stock by sending one lump-sum payment or issuance to DTC. The Rights Agent will have no responsibilities whatsoever with regard to the distribution of payments or shares of Common Stock by DTC to such street name holders.

(c) Subject to the restrictions on transferability set forth in Section 2.2, every request made to transfer a CVR must be in writing and accompanied by a written instrument of transfer in form reasonably satisfactory to the Rights Agent pursuant to its guidelines or procedures, including a guaranty of signature by an “eligible guarantor institution” that is a member or participant in the Securities Transfer Agents Medallion Program, duly executed and properly completed by the Holder thereof, the Holder’s attorney duly authorized in writing, the Holder’s personal representative or the Holder’s survivor, and setting forth in reasonable detail the circumstances relating to the transfer. Upon receipt of such written notice, the Rights Agent shall, subject to its reasonable determination that the transfer instrument is in proper form and the transfer otherwise complies with the other terms and conditions of this Agreement (including the provisions of Section 2.2), register the transfer of the CVRs in the CVR Register. The Company and Rights Agent may require evidence of payment of a sum sufficient to cover any stamp, documentary, registration, or other

Tax or governmental charge that is imposed in connection with any such registration of transfer (or evidence that such Taxes and charges are not applicable). The Rights Agent shall have no duty or obligation to take any action under any section of this Agreement that requires the payment by a Holder of a CVR of applicable taxes or charges unless and until the Rights Agent is satisfied that all such taxes or charges have been paid. All duly transferred CVRs registered in the CVR Register will be the valid obligations of the Company and will entitle the transferee to the same benefits and rights under this Agreement as those held immediately prior to the transfer by the transferor. No transfer of a CVR will be valid until registered in the CVR Register.

(d) A Holder may make a written request to the Rights Agent to change such Holder’s address of record in the CVR Register. The written request must be duly executed by the Holder. Upon receipt of such written notice, the Rights Agent shall, subject to its reasonable determination that the transfer instrument is in proper form, promptly record the change of address in the CVR Register. The Acting Holders may, without duplication, make a written request to the Rights Agent for a list containing the names, addresses and number of CVRs of the Holders that are registered in the CVR Register. Upon receipt of such written request from the Acting Holders, the Rights Agent shall promptly deliver a copy of such list to the Acting Holders.

(e) The Company will provide written instructions to the Rights Agent for the distribution of CVRs to holders of Common Stock as of immediately prior to the Effective Time (the “Record Time”). Subject to the terms and conditions of this Agreement and the Company’s prompt confirmation of the Effective Time, the Rights Agent shall effect the distribution of the CVRs, less any applicable tax withholding, to each holder of Common Stock as of the Record Time by the mailing of a statement of holding reflecting such CVRs.

Section 2.4 Payment Procedures.

(a) No later than forty-five (45) days following the end of each Calendar Quarter during the CVR Term beginning with the Calendar Quarter ending on [•], commencing with the first CVR Payment Period in which the Company or its Affiliates receives Gross Proceeds, the Company shall deliver to the Rights Agent a CVR Payment Statement for the such CVR Payment Period. Concurrent with the delivery of each CVR Payment Statement, on the terms and conditions of this Agreement, the Company shall pay the Rights Agent in U.S. dollars an amount equal to eighty percent (80%) of the Net Proceeds (if any) (subject to the proviso in the definition of the term “CVR Payment”) for the applicable CVR Payment Period. Such amount of Net Proceeds will be transferred by wire transfer of immediately available funds to an account designated in writing by the Rights Agent not less than twenty (20) Business Days prior to the date of the applicable payment. Upon receipt of the wire transfer referred to in the foregoing sentence, the Rights Agent shall promptly (and in any event, within ten (10) Business Days) pay, by check mailed, first-class postage prepaid, to the address each Holder set forth in the CVR Register at such time or by other method of deliver as specified by the applicable Holder in writing to the Rights Agent, an amount equal to such Holder’s CVR Payment Amount. The Rights Agent shall as soon as practicable after receipt of a CVR Payment Statement under this Section 2.4(b), send each Holder at its registered address a copy of such statement. For the avoidance of doubt the Company shall have no further liability in respect of the relevant CVR Payment upon delivery of such CVR Payment in accordance with this Section 2.4(b) and the satisfaction of each of the Company’s obligations set forth in this Section 2.4(b).

(b) The Rights Agent shall solicit from each Holder an IRS Form W-9 or applicable IRS Form W-8 at such time or times as is necessary to permit any payment under this Agreement to be made without U.S. federal backup withholding. That notwithstanding, the Company shall be entitled to deduct and withhold and hereby authorizes the Rights Agent to deduct and withhold, any tax or similar governmental charge or levy, that is required to be deducted or withheld under applicable law from any amounts payable pursuant to this Agreement (“Withholding Taxes”). To the extent the amounts are so withheld by the Company or the Rights Agent, as the case may be, and paid over to the appropriate

Governmental Authority, such withheld amounts shall be treated for all purposes of this Agreement as having been paid to the person in respect of whom such deduction and withholding was made. In the event the Company becomes aware that a payment under this Agreement is subject to Withholding Taxes (other than U.S. federal backup withholding), the Company shall use commercially reasonable efforts to provide written notice to the Rights Agent and the Rights Agent shall use commercially reasonable efforts to provide written notice of such Withholding Taxes to the applicable Holders and the Company and the Holders shall use commercially reasonable efforts cooperate with one another to minimize taxes required by applicable law to be withheld or deducted from any payments made under this Agreement. For the avoidance of doubt, in the event that notice has been provided to an applicable Holder pursuant to this Section 2.4(c), no further notice shall be required to be given for any future payments of such Withholding Tax. The Company will use commercially reasonable efforts to provide withholding and reporting instructions in writing (email being sufficient) to the Rights Agent from time to time as relevant, and upon reasonable request of the Rights Agent. The Rights Agent shall have no responsibilities with respect to tax withholding, reporting or payment except as set forth herein or as specifically instructed by the Company.

(c) Any portion of a CVR Payment that remains undistributed to the Holders six (6) months after the applicable Calendar Quarter end (including by means of uncashed checks or invalid addresses on the CVR Register) will be delivered by the Rights Agent to the Company or a person nominated in writing by the Company (with written notice thereof from the Company to the Rights Agent), and any Holder will thereafter look only to the Company for payment of such CVR Payment (which shall be without interest).

(d) If any CVR Payment (or portion thereof) remains unclaimed by a Holder two (2) years after the applicable Calendar Quarter end (or immediately prior to such earlier date on which such CVR Payment would otherwise escheat to or become the property of any Governmental Authority), such CVR Payment (or portion thereof) will, to the extent permitted by applicable Law, become the property of the Company and will be transferred to the Company or a person nominated in writing by the Company (with written notice thereof from the Company to the Rights Agent), free and clear of all claims or interest of any Person previously entitled thereto, and no consideration or compensation shall be payable therefor. Neither the Company nor the Rights Agent will be liable to any Person in respect of a CVR Payment delivered to a public official pursuant to any applicable abandoned property, escheat or similar legal requirement under applicable Law. In addition to and not in limitation of any other indemnity obligation herein, the Company agrees to indemnify and hold harmless the Rights Agent with respect to any liability, penalty, cost or expense the Rights Agent may incur or be subject to in connection with transferring such property to the Company, a public office or a person nominated in writing by the Company.

Section 2.5 No Voting, Dividends or Interest; No Equity or Ownership Interest.

(a) If and when issued, the CVRs will not have any voting or dividend rights, and interest will not accrue on any amounts payable in respect of CVRs to any Holder.

(b) If and when issued, the CVRs will not represent any equity or ownership interest in the Company or in any constituent company to the Merger. It is hereby acknowledged and agreed that a CVR shall not constitute a security of the Company.

(c) Nothing contained in this Agreement shall be construed as conferring upon any Holder, by virtue of the CVRs, any rights or obligations of any kind or nature whatsoever as a stockholder or member of the Company or any of its subsidiaries either at law or in equity. The rights of any Holder and the obligations of the Company and its Affiliates and their respective officers, directors and controlling Persons are contract rights limited to those expressly set forth in this Agreement.

(d) It is hereby acknowledged and agreed that the CVRs and the possibility of any payment hereunder with respect thereto are highly speculative and subject to numerous factors outside of the Company’s control, and there is no assurance that Holders will receive any payments under this Agreement or in connection with the CVRs. Each Holder acknowledges that it is highly possible that no Disposition

will occur prior to the expiration of the Disposition Period and that there will not be any Gross Proceeds that may be the subject of a CVR Payment Amount. It is further acknowledged and agreed that neither the Company nor its Affiliates owe, by virtue of their obligations under this Agreement, a fiduciary duty or any implied duties to the Holders and the parties hereto intend solely the express provisions of this Agreement to govern their contractual relationship with respect to the CVRs. It is acknowledged and agreed that this Section 2.5(d) is an essential and material term of this Agreement.

Section 2.6 Ability to Abandon CVR. A Holder may at any time, at such Holder’s option, abandon all of such Holder’s remaining rights represented by CVRs by transferring such CVR to the Company or a Person nominated in writing by the Company (with written notice thereof from the Company to the Rights Agent) without consideration in compensation therefor, and such rights will be cancelled, with the Rights Agent being promptly notified in writing by the Company of such transfer and cancellation. Nothing in this Agreement is intended to prohibit the Company or its Affiliates from offering to acquire or acquiring CVRs, in private transactions or otherwise, for consideration in its sole discretion.

ARTICLE 3

THE RIGHTS AGENT

Section 3.1 Certain Duties and Responsibilities.

(a) The Rights Agent will not have any liability for any actions taken or not taken in connection with this Agreement, except to the extent such liability arises as a result of the willful misconduct, bad faith or gross negligence of the Rights Agent (in each case as determined by a final non-appealable judgment of court of competent jurisdiction). Notwithstanding anything in this Agreement to the contrary, any liability of the Rights Agent under this Agreement will be limited to the amount of annual fees paid by the Company to the Rights Agent in connection with this Agreement (but not including reimbursable expenses and other charges) during the eighteen (18) months immediately preceding the event for which recovery from the Rights Agent is being sought. Anything to the contrary notwithstanding, in no event will the Rights Agent be liable for special, punitive, indirect, incidental or consequential loss or damages of any kind whatsoever (including, without limitation, lost profits), even if the Rights Agent has been advised of the likelihood of such loss or damages, and regardless of the form of action.

(b) The Rights Agent shall not have any duty or responsibility in the case of the receipt of any written demand from any Holder with respect to any action or default by any person or entity, including, without limiting the generality of the foregoing, any duty or responsibility to initiate or attempt to initiate any proceedings at law or otherwise or to make any demand upon the Company or Dianthus. The Rights Agent may (but shall not be required to) enforce all rights of action under this Agreement and any related claim, action, suit, audit, investigation or proceeding instituted by the Rights Agent may be brought in its name as the Rights Agent and any recovery in connection therewith will be for the proportionate benefit of all the Holders, as their respective rights or interests may appear on the CVR Register.

Section 3.2 Certain Rights of Rights Agent.

(a) The Rights Agent undertakes to perform such duties and only such duties as are specifically set forth in this Agreement, and no implied covenants or obligations will be read into this Agreement against the Rights Agent.

(b) The Rights Agent may rely and will be protected by the Company in acting or refraining from acting upon any resolution, certificate, statement, instrument, opinion, report, notice, request, direction, consent, order or other paper or document reasonably believed by it to be genuine and to have been signed or presented by or on behalf of the Company or, with respect to Section 2.3(d), the Acting Holders.

(c) Whenever the Rights Agent deems it desirable that a matter be proved or established prior to taking or omitting any action hereunder, the Rights Agent may rely upon an Officer’s Certificate, which certificate shall be full authorization and protection to the Rights Agent, and the Rights Agent shall, in the absence of bad faith, gross negligence or willful misconduct (each as determined by a final non-appealable judgment of a court of competent jurisdiction) on its part, not incur any liability and shall be held harmless by the Company for or in respect of any action taken or omitted to be taken by it under the provisions of this Agreement in reliance upon such Officer’s Certificate.

(d) The Rights Agent may engage and consult with counsel of its selection, and the advice or opinion of such counsel will, in the absence of bad faith, gross negligence or willful misconduct (in each case, as determined by a final, non-appealable judgment of a court of competent jurisdiction) on the part of the Rights Agent, be full and complete authorization and protection in respect of any action taken or not taken by the Rights Agent in reliance thereon.

(e) Any permissive rights of the Rights Agent hereunder will not be construed as a duty.

(f) The Rights Agent will not be required to give any note or surety in respect of the execution of its powers or otherwise under this Agreement.

(g) The Company agrees to indemnify the Rights Agent for, and to hold the Rights Agent harmless from and against, any loss, liability, damage, judgment, fine, penalty, cost or expense (each, a “Loss”) suffered or incurred by the Rights Agent and arising out of or in connection with the Rights Agent’s performance of its obligations under this Agreement, including the reasonable and documented costs and expenses of defending the Rights Agent against any claims, charges, demands, actions or suits arising out of or in connection in connection with the execution, acceptance, administration, exercise and performance of its duties under this Agreement, including the costs and expenses of defending against any claim of liability arising therefrom, directly or indirectly, or enforcing its rights hereunder, except to the extent such Loss has been determined by a final non-appealable decision of a court of competent jurisdiction to have resulted from the Rights Agent’s gross negligence, bad faith or willful misconduct; provided that this Section 3.2(g) shall not apply with respect to income, receipt, franchise or similar Taxes levied against the Rights Agent by a Governmental Authority.

(h) The Company agrees (i) to pay the fees of the Rights Agent in connection with the Rights Agent’s performance of its obligations hereunder as set forth in Exhibit A and agreed upon in writing by the Rights Agent and the Company on or prior to the date of this Agreement, and (ii) to reimburse the Rights Agent for all reasonable and documented out-of-pocket expenses and other disbursements incurred in the preparation, delivery, negotiation, amendment, administration and execution of this Agreement and the exercise and performance of its duties hereunder, including all stamp and transfer Taxes (and excluding for the avoidance of doubt, any income, receipt, franchise or similar Taxes levied against the Rights Agent by a Governmental Authority) and governmental charges, incurred by the Rights Agent in the performance of its obligations under this Agreement, except that the Company will have no obligation to pay the fees of the Rights Agent or reimburse the Rights Agent for the fees of counsel in connection with any lawsuit initiated by the Rights Agent on behalf of itself or the Holders, except in the case of any suit enforcing the provisions of Section 2.4(a), Section 2.4(b) or Section 3.2(g), if the Company is found by a court of competent jurisdiction to be liable to the Rights Agent or the Holders, as applicable in such suit.

(i) No provision of this Agreement shall require the Rights Agent to expend or risk its own funds or otherwise incur any financial liability in the performance of any of its duties hereunder or in the exercise of any of its rights or powers if it believes that repayment of such funds or adequate indemnification against such risk or liability is not reasonably assured to it.

(j) The Rights Agent shall have no responsibility to the Company, any holders of CVRs, any holders of shares of Common Stock or any other Person for interest or earnings on any moneys held by the Rights Agent pursuant to this Agreement.

(k) The Rights Agent shall not be subject to, nor be required to comply with, or determine if any Person has complied with, the Merger Agreement or any other agreement between or among any the Company, Dianthus or Holders, even though reference thereto may be made in this Agreement, or to comply with any notice, instruction, direction, request or other communication, paper or document other than as expressly set forth in this Agreement.

(l) Subject to applicable Law, (i) the Rights Agent and any shareholder, affiliate, director, officer or employee of the Rights Agent may buy, sell or deal in any securities of the Company or Dianthus or become peculiarly interested in any transaction in which such parties may be interested, or contract with or lend money to such parties or otherwise act as fully and freely as though it were not the Rights Agent under this Agreement, and (ii) nothing herein will preclude the Rights Agent from acting in any other capacity for the Company or for any other Person.

(m) In the event the Rights Agent reasonably believes any ambiguity or uncertainty exists hereunder or in any notice, instruction, direction, request or other communication, paper or document received by the Rights Agent hereunder, the Rights Agent shall, as soon as practicable, provide notice to the Company, and the Rights Agent, may, in its sole discretion, refrain from taking any action, and shall be fully protected and shall not be liable in any way to the Company or any Holder or any other Person for refraining from taking such action, unless the Rights Agent receives written instructions from the Company or such Holder or other Person which eliminate such ambiguity or uncertainty to the reasonable satisfaction of the Rights Agent;

(n) The Rights Agent may execute and exercise any of the rights or powers hereby vested in it or perform any duty hereunder either itself or by or through its attorney or agents and the Rights Agent shall not be answerable or accountable for any act, default, neglect or misconduct of any such attorney or agents or for any loss to the Company or Dianthus resulting from any such act, default, neglect or misconduct, absent gross negligence, bad faith or willful misconduct (each as determined by a final non-appealable judgment of a court of competent jurisdiction) in the selection and continued employment thereof.

(o) The Rights Agent shall not be liable for or by reason of any of the statements of fact or recitals contained in this Agreement (except its countersignature thereof) or be required to verify the same, and all such statements and recitals are and shall be deemed to have been made by the Company only.

(p) The Rights Agent shall act hereunder solely as agent for the Company and shall not assume any obligations or relationship of agency or trust with any of the owners or holders of the CVRs. The Rights Agent shall not have any duty or responsibility in the case of the receipt of any written demand from any Holders with respect to any action or default by the Company, including, without limiting the generality of the foregoing, any duty or responsibility to initiate or attempt to initiate any proceedings at law or otherwise or to make any demand upon the Company.

(q) The Rights Agent may rely on and be fully authorized and protected in acting or failing to act upon (a) any guaranty of signature by an “eligible guarantor institution” that is a member or participant in the Securities Transfer Agents Medallion Program or other comparable “signature guarantee program” or insurance program in addition to, or in substitution for, the foregoing; or (b) any law, act, regulation or any interpretation of the same even though such law, act, or regulation may thereafter have been altered, changed, amended or repealed.

(r) The Rights Agent shall not be liable or responsible for any failure of the Company to comply with any of its obligations relating to any registration statement filed with the Securities and Exchange Commission or this Agreement, including without limitation obligations under applicable regulation or law.

(s) The obligations of the Company and the rights of the Rights Agent under this Section 3.2, Section 3.1 and Section 2.4 shall survive the expiration of the CVRs and the termination of this Agreement and the resignation, replacement or removal of the Rights Agent.

Section 3.3 Resignation and Removal; Appointment of Successor.

(a) The Rights Agent may resign at any time by written notice to the Company. Any such resignation notice shall specify the date on which such resignation will take effect (which shall be at least thirty (30) days following the date that such resignation notice is delivered), and such resignation will be effective on the earlier of (x) the date so specified and (y) the appointment of a successor Rights Agent.

(b) The Company will have the right to remove the Rights Agent at any time by written notice to the Rights Agent, specifying the date on which such removal will take effect. Such notice will be given at least thirty (30) days prior to the date so specified (or, if earlier, the appointment of the successor Rights Agent).

(c) If the Rights Agent resigns, is removed or becomes incapable of acting, the Company will promptly appoint a qualified successor Rights Agent. Notwithstanding the foregoing, if the Company fails to make such appointment within a period of thirty (30) days after giving notice of such removal or after it has been notified in writing of such resignation or incapacity by the resigning or incapacitated Rights Agent, then the incumbent Rights Agent may apply to any court of competent jurisdiction for the appointment of a new Rights Agent. The successor Rights Agent so appointed will, upon its acceptance of such appointment in accordance with this Section 3.3(c) and Section 3.4, become the Rights Agent for all purposes hereunder.

(d) The Company will give notice to the Holders of each resignation or removal of the Rights Agent and each appointment of a successor Rights Agent in accordance with Section 7.2. Each notice will include the name and address of the successor Rights Agent. If the Company fails to send such notice within ten (10) Business Days after acceptance of appointment by a successor Rights Agent, the successor Rights Agent will cause the notice to be mailed at the expense of the Company.

(e) Notwithstanding anything to the contrary in this Section 3.3, unless consented to in writing by the Acting Holders, the Company will not appoint as a successor Rights Agent any Person that is not a stock transfer agent of national reputation or the corporate trust department of a commercial bank.

(f) The Rights Agent will reasonably cooperate with the Company and any successor Rights Agent in connection with the transition of the duties and responsibilities of the Rights Agent to the successor Rights Agent, including the transfer of all relevant data, including the CVR Register, to the successor Rights Agent, but such predecessor Rights Agent shall not be required to make any additional expenditure or assume any additional liability in connection with the foregoing.

Section 3.4 Acceptance of Appointment by Successor. Every successor Rights Agent appointed hereunder will, at or prior to such appointment, execute, acknowledge and deliver to the Company and to the resigning or removed Rights Agent an instrument accepting such appointment and a counterpart of this Agreement, and such successor Rights Agent, without any further act, deed or conveyance, will become vested with all the rights, powers, trusts and duties of the Rights Agent; provided that upon the request of the Company or the successor Rights Agent, such resigning or removed Rights Agent will execute and deliver an instrument transferring to such successor Rights Agent all the rights, powers and trusts of such resigning or removed Rights Agent.

ARTICLE 4

COVENANTS

Section 4.1 List of Holders. The Company will furnish or cause to be furnished to the Rights Agent, in such form as the Company receives from the Company’s transfer agent (or other agent performing similar services for the Company), the names and addresses of the Holders within fifteen (15) Business Days following the Closing Date.

Section 4.2 No Obligations of Public Company. Notwithstanding anything herein to the contrary, and for the avoidance of doubt, (a) the Company and its Affiliates shall have the power and right to control all aspects of their businesses and operations (and all of their assets and products), and subject to its compliance

with the terms of this Agreement, the Company and its Affiliates may exercise or refrain from exercising such power and right as it may deem appropriate and in the best overall interests of the Company and its Affiliates and its and their stockholders, rather than the interest of the Holders, (b) none of the Company or any of its Affiliates (or any directors, officer, employee, or other representative of the foregoing) owes any fiduciary duty or similar duty to any Holder in respect of the Potentially Transferable Assets, and (c) following the Disposition Period, the Company shall be permitted to take any action in respect of the Potentially Transferable Assets in order to satisfy any wind-down and termination Liabilities of the Potentially Transferable Assets.

Section 4.3 Prohibited Actions. Unless approved by the Acting Holders, prior to the end of the Disposition Period, the Company shall not grant any lien, security interest, pledge or similar interest in any Potentially Transferable Assets or any Net Proceeds. Unless approved by the Acting Holders, prior to end of the Disposition Period, the Company shall not, and shall not permit its Affiliates to, grant, assign, transfer or otherwise convey any Potentially Transferrable Assets (including any option to obtain rights) to any third party.

Section 4.4 Books and Records. Until the end of the CVR Term, the Company shall, and shall cause its Affiliates to, keep true, complete and accurate records in sufficient detail to enable the Rights Agent to confirm the applicable CVR Payment Amount payable hereunder in accordance with the terms specified in this Agreement.

Section 4.5 Audits. Until the expiration of this Agreement and for a period of one (1) year thereafter, the Company shall keep complete and accurate records in sufficient detail to support the accuracy of the payments due hereunder. The Acting Holders shall have the right to cause an independent accounting firm reasonably acceptable to the Company to audit such records for the sole purpose of confirming payments for a period covering not more than the date commencing with the first CVR Payment Period in which the Company or its Affiliates receives Gross Proceeds and ending on the last day of the CVR Term. The Company may require such accounting firm to execute a reasonable confidentiality agreement with the Company prior to commencing the audit. The accounting firm shall disclose to Rights Agent or the Acting Holders, as applicable, only whether the reports are correct or not and the specific details concerning any discrepancies. No other information shall be shared. Such audits may be conducted during normal business hours upon reasonable prior written notice to the Company, but no more than frequently than once per year. No accounting period of the Company shall be subject to audit more than one time by the Acting Holders, as applicable, unless after an accounting period has been audited by the Acting Holders, as applicable, the Company restates its financial results for such accounting period, in which event the Acting Holders, as applicable, may conduct a second audit of such accounting period in accordance with this Section 4.5. Adjustments (including remittances of underpayments or overpayments disclosed by such audit) shall be made by the Company to reflect the results of such audit, which adjustments shall be paid promptly following receipt of an invoice therefor. Whenever such an adjustment is made, the Company shall promptly prepare a certificate setting forth such adjustment, and a brief, reasonably detailed statement of the facts, computation and methodology accounting for such adjustment to the extent not already reflected in the audit report and promptly file with the Rights Agent a copy of such report and promptly deliver to the Rights Agent a revised CVR Payment Statement for the relevant CVR Payment Period. The Rights Agent shall be fully protected in relying on any such report and on any adjustment or statement therein contained and shall have no duty or liability with respect to, and shall not be deemed to have knowledge of any such adjustment or any such event unless and until it shall have received such report. The Acting Holders, as applicable, shall bear the full cost and expense of such audit unless such audit discloses an underpayment by the Company of ten percent (10%) or more of the CVR Payment Amount due under this Agreement, in which case the Company shall bear the full cost and expense of such audit. The Rights Agent shall be entitled to rely on any audit report delivered by the independent accounting firm pursuant to this Section 4.5.

ARTICLE 5

AMENDMENTS

Section 5.1 Amendments Without Consent of Holders or Rights Agent.

(a) The Company, at any time and from time to time, may (without the consent of any Person, other than the Rights Agent, with such consent not to be unreasonably withheld, conditioned or delayed) enter into one or more amendments to this Agreement for any of the following purposes: