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 Act of 1934

Date of Report (Date of earliest event reported): November 19, 2018

MAGENTA THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

100 Technology Square

Cambridge, Massachusetts 02139

(857) 242-0170

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

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:

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.  ☐

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On November 19, 2018, Magenta Therapeutics, Inc. (the “Company”) announced the appointment of Jason Ryan, age 44, as Chief Operating and Financial Officer of the Company, effective January 1, 2019 (the “Effective Date”).

Mr. Ryan previously served as Chief Financial Officer of Foundation Medicine, Inc. (“Foundation”), which became a wholly-owned subsidiary of Roche Holdings, Inc., from March 2015. Prior to his position as Chief Financial Officer of Foundation, Mr. Ryan served as the Senior Vice President, Finance from January 2014 to March 2015, as the Vice President of Finance from March 2012 to January 2014, and as the Senior Director, Finance from May 2011 to March 2012. Prior to joining Foundation, Mr. Ryan led the finance and strategic planning functions of Taligen Therapeutics, Inc., which was acquired by Alexion Pharmaceuticals, Inc. (NASDAQ: ALXN), from May 2009 to April 2011, Codon Devices Inc. from May 2007 to May 2009 and Genomics Collaborative, Inc., which was acquired by SeraCare Life Sciences, Inc. (NASDAQ: SRLS), from September 1998 to September 2004. He began his career at Deloitte & Touche. Mr. Ryan holds a B.S. in economics from Bates College and an M.B.A. from Babson College, and earned a C.P.A. in Massachusetts.

In connection with his employment, the Company and Mr. Ryan entered into an Employment Agreement, effective as of the Effective Date (the “Employment Agreement”), which sets forth certain terms of Mr. Ryan’s employment. There are no other arrangements or understandings between Mr. Ryan and any other persons pursuant to which he was selected as the Company’s Chief Operating and Financial Officer. Additionally, there are no transactions involving the Company and Mr. Ryan that the Company would be required to report pursuant to Item 404(a) of Regulation S-K.

Pursuant to the terms of the Employment Agreement, Mr. Ryan will receive a one-time sign-on bonus of $25,000 and an initial annual base salary of $400,000. In addition, he will be eligible to receive an annual performance bonus targeted at up to 40% of his annual base salary, pro-rated to his start date.

The Employment Agreement further provides that, subject to the approval of the Compensation Committee of the Board of Directors, Mr. Ryan is entitled to an option to purchase 329,379 shares of the Company’s common stock under the Company’s 2018 Stock Option and Incentive Plan. Mr. Ryan will also be eligible to participate in all customary employee benefit plans or programs of the Company generally available to the Company’s full-time employees and/or executive officers.

In the event Mr. Ryan’s employment is terminated without cause or Mr. Ryan terminates his employment for good reason, then, subject to Mr. Ryan entering into a separation agreement with the Company, he will be eligible to receive: (i) compensation in an amount equal to 0.75 times of his then current base salary and (ii) subject to his election of Consolidated Omnibus Budget Reconciliation Act (“COBRA”) health continuation coverage, monthly contributions for up to nine months, monthly contributions until he becomes eligible for group health coverage through other employment, or his COBRA health continuation period, whichever ends earlier.

In the event that such termination without cause or resignation for good reason occurs within a twelve-month period following a change of control transaction, then Mr. Ryan shall be entitled to receive: (i) a cash amount equal to 1.0 times the sum of his then current base salary plus his target annual incentive compensation, (ii) 100% acceleration of all equity awards held as of the date of termination, (iii) subject to his election of COBRA health continuation coverage, monthly contributions for up to 12 months, monthly contributions until he becomes eligible for group health coverage through other employment, or his COBRA health continuation period, whichever ends earlier. All references to “cause,” “good reason” and “change in control” are as defined in the Employment Agreement.

The foregoing description of the Employment Agreement does not purport to be complete and is qualified in its entirety by reference to such agreement, a copy of which is attached to this Current Report on Form 8-K as Exhibit 99.1 and incorporated herein by reference.

2

In connection with Mr. Ryan’s appointment as Chief Operating and Financial Officer, the Company issued a press release on November 19, 2018 titled “Magenta Therapeutics Appoints Jason Ryan as Chief Operating and Financial Officer”, a copy of which is filed herewith as Exhibit 99.2 and is incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

3

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.

4

Exhibit 99.1

EMPLOYMENT AGREEMENT

This Employment Agreement (“Agreement”) is made by and between Magenta Therapeutics, Inc., a Delaware corporation (the “Company”), and Jason Ryan (the “Executive”), and is effective as of the first date of the Executive’s employment with the Company (the “Effective Date”). Except with respect to the Restrictive Covenant Agreement and the Equity Documents (each as defined below), this Agreement supersedes, amends and restates in all respects all prior agreements between the Executive and the Company regarding the subject matter herein, including without limitation any offer letter, employment agreement or severance agreement.

WHEREAS, the Company desires to employ the Executive and the Executive desires to be employed by the Company on the terms contained herein.

NOW, THEREFORE, in consideration of the mutual covenants and agreements herein contained and other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties agree as follows:

1. Employment.

a) Term. The Company and the Executive desire that their employment relationship be subject to this Agreement commencing as of the Effective Date and continuing in effect until terminated by either party in accordance with this Agreement (the “Term”). The Executive’s employment with the Company will continue to be “at will,” meaning that the Executive’s employment may be terminated by the Company or the Executive at any time and for any reason subject to the terms of this Agreement.

b) Position and Duties. During the Term, the Executive shall serve as the Chief Operating and Financial Officer of the Company, and shall have powers and duties that may from time to time be prescribed by the Company’s Chief Executive Officer (the “CEO”) or another authorized executive. The Executive shall devote his full working time and efforts to the business and affairs of the Company. Notwithstanding the foregoing, the Executive may serve on up to two other boards of directors, with the prior written approval of the Board of Directors of the Company (the “Board”). Further, the Executive may engage in religious, charitable or other community activities as long as such services and activities are disclosed to the Board and do not interfere with the Executive’s performance of his duties to the Company as provided in this Agreement. The Executive reaffirms that he has no contractual commitments or other legal obligations that would prohibit him from fully performing his duties for the Company.

2. Compensation and Related Matters.

a) Base Salary. The Executive’s annual base salary shall be $400,000.00, which is subject to review and redetermination by the Compensation Committee. The base salary in effect at any given time is referred to herein as “Base Salary.” The Base Salary shall be payable in a manner that is consistent with the Company’s usual payroll practices for senior executives.

b) Incentive Compensation. During the Term, the Executive shall be eligible to receive cash incentive compensation as determined by the Board or the Compensation Committee from time to time. The Executive’s target annual incentive compensation shall be 40 percent of his Base Salary, as may be redetermined from time to time (the “Target Incentive Compensation”). To earn incentive compensation, the Executive must be employed by the Company on the day such incentive compensation is paid.

c) Expenses. The Executive shall be entitled to receive prompt reimbursement for all reasonable expenses incurred by him during the Term in performing services hereunder, in accordance with the policies and procedures then in effect and established by the Company for its senior executive officers.

d) Other Benefits. During the Term, the Executive shall be entitled to continue to participate in or receive benefits under the Company’s employee benefit plans in effect from time to time, including paid sick time under applicable law, subject to the terms of such plans and to the Company’s ability to amend, modify, replace or terminate such plans and programs.

e) Vacations. During the Term, the Executive shall be entitled to accrue up to 20 paid vacation days in each calendar year, except for calendar year 2019, where the Executive will accrue up to 25 paid vacation days. Vacation days shall be accrued ratably and must be used in accordance with the Company’s vacation policy. The Executive shall also be entitled to all paid holidays given by the Company to its executives.

f) Equity. The equity awards held by the Executive shall be governed by the terms and conditions of the Company’s applicable equity incentive plan(s) and the applicable award agreement(s) governing the terms of such equity awards held by the Executive (collectively, the “Equity Documents”); provided, however, and notwithstanding anything to the contrary in the Equity Documents, Section 6(a)(ii) of this Agreement shall apply in the event of a termination by the Company without Cause or by the Executive for Good Reason in either event within the Change in Control Period (as such terms are defined below).

g) Sign-On Bonus. The Company shall pay the Executive a one-time sign-on bonus of $25,000, less applicable deductions and withholdings (the “Sign-On Bonus”), to be paid within thirty (30) days after the Effective Date. The Executive agrees that if he terminates his employment for any reason or if the Company terminates his employment with Cause (as defined below), in each case prior to the one year anniversary of the Effective Date, he will repay the entire Sign-On Bonus within 30 days of the Date of Termination (as defined below).

3. Termination. During the Term, the Executive’s employment hereunder may be terminated without any breach of this Agreement under the following circumstances:

a) Death. The Executive’s employment hereunder shall terminate upon his death.

2

b) Disability. The Company may terminate the Executive’s employment if he is disabled and unable to perform the essential functions of the Executive’s then existing position or positions under this Agreement with or without reasonable accommodation for a period of 180 days (which need not be consecutive) in any 12-month period. If any question shall arise as to whether during any period the Executive is disabled so as to be unable to perform the essential functions of the Executive’s then existing position or positions with or without reasonable accommodation, the Executive may, and at the request of the Company shall, submit to the Company a certification in reasonable detail by a physician selected by the Company to whom the Executive or the Executive’s guardian has no reasonable objection as to whether the Executive is so disabled or how long such disability is expected to continue, and such certification shall for the purposes of this Agreement be conclusive of the issue. The Executive shall cooperate with any reasonable request of the physician in connection with such certification. If such question shall arise and the Executive shall fail to submit such certification, the Company’s determination of such issue shall be binding on the Executive. Nothing in this Section 3(b) shall be construed to waive the Executive’s rights, if any, under existing law including, without limitation, the Family and Medical Leave Act of 1993, 29 U.S.C. §2601 et seq, and the Americans with Disabilities Act, 42 U.S.C. §12101 et seq.

c) Termination by Company for Cause. The Company may terminate the Executive’s employment hereunder for Cause. For purposes of this Agreement, “Cause” shall mean: (i) the Executive’s dishonest statements or acts with respect to the Company or any affiliate of the Company, or any current or prospective customers, suppliers vendors or other third parties with which such entity does business; (ii) the Executive’s commission of (A) a felony or (B) any misdemeanor involving moral turpitude, deceit, dishonesty or fraud; (iii) the Executive’s failure to perform his assigned duties and responsibilities to the reasonable satisfaction of the Company which failure continues, in the reasonable judgment of the Company, for thirty (30) days after written notice given to the Executive by the Company; (iv) the Executive’s gross negligence, willful misconduct or insubordination with respect to the Company or any affiliate of the Company; or (v) the Executive’s material violation of any provision of any agreement(s) between the Executive and the Company relating to noncompetition, nonsolicitation, nondisclosure and/or assignment of inventions.

d) Termination without Cause. The Company may terminate the Executive’s employment hereunder at any time without Cause. Any termination by the Company of the Executive’s employment under this Agreement which does not constitute a termination for Cause under Section 3(c) and does not result from the death or disability of the Executive under Section 3(a) or (b) shall be deemed a termination without Cause.

e) Termination by the Executive. The Executive may terminate his employment hereunder at any time for any reason, including but not limited to Good Reason. For purposes of this Agreement, “Good Reason” shall mean that the Executive has complied with the “Good Reason Process” (hereinafter defined) following the occurrence of any of the following events: (i) a material diminution in the Executive’s responsibilities, authority or duties; (ii) a material diminution in the Executive’s Base Salary except for across-the-board salary reductions based on the Company’s financial performance similarly affecting all or substantially all senior management employees of the Company; (iii) a material change in the geographic location, which would be a move of greater than 25 miles from the current location (judging from a straight line projecting out from the current home office to form the radius of a circle around the current location), at which the Executive provides services to the Company; or (iv) the material breach of this Agreement by the Company. “Good Reason Process” shall mean that

3

(i) the Executive reasonably determines in good faith that a “Good Reason” condition has occurred; (ii) the Executive notifies the Company in writing of the first occurrence of the Good Reason condition within 60 days of the first occurrence of such condition; (iii) the Executive cooperates in good faith with the Company’s efforts, for a period not less than 30 days following such notice (the “Cure Period”), to remedy the condition; (iv) notwithstanding such efforts, the Good Reason condition continues to exist; and (v) the Executive terminates his employment within 60 days after the end of the Cure Period. If the Company cures the Good Reason condition during the Cure Period, Good Reason shall be deemed not to have occurred.

If the Executive’s employment with the Company is terminated for any reason, the Company shall pay or provide to the Executive (or to his authorized representative or estate) (i) any Base Salary earned through the Date of Termination, unpaid expense reimbursements (subject to, and in accordance with, Section 2(c) of this Agreement) and unused vacation that accrued through the Date of Termination on or before the time required by law but in no event more than 30 days after the Executive’s Date of Termination; and (ii) any vested benefits the Executive may have under any employee benefit plan of the Company through the Date of Termination, which vested benefits shall be paid and/or provided in accordance with the terms of such employee benefit plans (collectively, the “Accrued Benefit”).

4. Notice and Date of Termination.

a) Notice of Termination. Except for termination as specified in Section 3(a), any termination of the Executive’s employment by the Company or any such termination by the Executive shall be communicated by written Notice of Termination to the other party hereto. For purposes of this Agreement, a “Notice of Termination” shall mean a notice which shall indicate the specific termination provision in this Agreement relied upon.

b) Date of Termination. “Date of Termination” shall mean: (i) if the Executive’s employment is terminated by his death, the date of his death; (ii) if the Executive’s employment is terminated on account of disability under Section 3(b) or by the Company for Cause under Section 3(c), the date on which Notice of Termination is given; (iii) if the Executive’s employment is terminated by the Company under Section 3(d), the date on which a Notice of Termination is given; (iv) if the Executive’s employment is terminated by the Executive under Section 3(e) without Good Reason, 30 days after the date on which a Notice of Termination is given, and (v) if the Executive’s employment is terminated by the Executive under Section 3(e) for Good Reason, the date on which a Notice of Termination is given after the end of the Cure Period. Notwithstanding the foregoing, in the event that the Executive gives a Notice of Termination to the Company, the Company may unilaterally accelerate the Date of Termination and such acceleration shall not result in a termination by the Company for purposes of this Agreement.

5. Compensation Upon Termination by the Company without Cause or by the Executive for Good Reason Outside the Change in Control Period. During the Term, if the Executive’s employment is terminated by the Company without Cause as provided in Section 3(d), or the Executive terminates his employment for Good Reason as provided in Section 3(e), each outside of the Change in Control Period (as defined below), then the Company shall pay the Executive his Accrued Benefit. In addition, subject to the Executive signing a separation agreement and release substantially in the form attached hereto as Exhibit A (the “Separation Agreement and Release”) and the Separation Agreement and Release becoming irrevocable, all within 60 days after the Date of Termination (or such shorter period as set forth in the Separation Agreement and Release):

4

a) the Company shall pay the Executive an amount equal to 0.75 times the Executive’s Base Salary (the “Severance Amount”). Notwithstanding the foregoing, if the Executive breaches any of the provisions contained in Section 8 of this Agreement or the Restrictive Covenant Agreement, all payments of the Severance Amount shall immediately cease; and

b) if the Executive was participating in the Company’s group health plan immediately prior to the Date of Termination and elects COBRA health continuation, then the Company shall pay the monthly employer COBRA premium for the same level of group health coverage as in effect for the Executive on the Date of Termination until the earliest of the following: (i) the nine (9) month anniversary of the Date of Termination; (ii) the Executive’s eligibility for group health coverage through other employment; or (iii) the end of the Executive’s eligibility under COBRA for continuation coverage for health care. Notwithstanding the foregoing, if the Company determines at any time that its payments pursuant to this paragraph may be taxable income to the Executive, it may convert such payments to payroll payments directly to the Executive on the Company’s regular payroll dates, which shall be subject to tax-related deductions and withholdings.

The amounts payable under this Section 5 shall be paid out in substantially equal installments in accordance with the Company’s payroll practice over nine (9) months commencing within 60 days after the Date of Termination; provided, however, that if the 60-day period begins in one calendar year and ends in a second calendar year, the Severance Amount shall begin to be paid in the second calendar year by the last day of such 60-day period; provided, further, that the initial payment shall include a catch-up payment to cover amounts retroactive to the day immediately following the Date of Termination. Each payment pursuant to this Agreement is intended to constitute a separate payment for purposes of Treasury Regulation Section l.409A-2(b)(2).

6. Compensation Upon Termination by the Company without Cause or by the Executive for Good Reason within the Change in Control Period. The provisions of this Section 6 shall apply in lieu of, and expressly supersede, the provisions of Section 5 regarding severance pay and benefits upon a termination by the Company without Cause or by the Executive for Good Reason if such termination of employment occurs within 12 months after the occurrence of the first event constituting a Change in Control (such period, the “Change in Control Period”). These provisions shall terminate and be of no further force or effect beginning 12 months after the occurrence of a Change in Control.

a) Change in Control. If during the Change in Control Period the Executive’s employment is terminated by the Company without Cause as provided in Section 3(d) or the Executive terminates his employment for Good Reason as provided in Section 3(e), then, subject to the signing of the Separation Agreement and Release by the Executive and the Separation Agreement and Release becoming irrevocable, all within 60 days after the Date of Termination (or such shorter period as set forth in the Separation Agreement and Release),

5

(i) the Company shall pay the Executive a lump sum in cash in an amount equal to the sum of (A) one (1) times the Executive’s current Base Salary (or the Executive’s Base Salary in effect immediately prior to the Change in Control, if higher) plus (B) 100 percent of the Executive’s Target Incentive Compensation (the “Change in Control Payment”); and

(ii) notwithstanding anything to the contrary in any applicable option agreement or stock-based award agreement, all time-based stock options and other stock-based awards held by the Executive shall immediately accelerate and become fully exercisable or nonforfeitable as of the Date of Termination; and

(iii) if the Executive was participating in the Company’s group health plan immediately prior to the Date of Termination and elects COBRA health continuation, then the Company shall pay the monthly employer COBRA premium for the same level of group health coverage as in effect for the Executive on the Date of Termination until the earliest of the following: (i) the 12 month anniversary of the Date of Termination; (ii) the Executive’s eligibility for group health coverage through other employment; or (iii) the end of the Executive’s eligibility under COBRA for continuation coverage for health care. Notwithstanding the foregoing, if the Company determines at any time that its payments pursuant to this paragraph may be taxable income to the Executive, it may convert such payments to payroll payments directly to the Executive on the Company’s regular payroll dates, which shall be subject to tax-related deductions and withholdings.

The amounts payable under this Section 6(a) shall be paid or commence to be paid within 60 days after the Date of Termination; provided, however, that if the 60-day period begins in one calendar year and ends in a second calendar year, such payment shall be paid or commence to be paid in the second calendar year by the last day of such 60-day period.

(b) Additional Limitation.

(i) Anything in this Agreement to the contrary notwithstanding, in the event that the amount of any compensation, payment or distribution by the Company to or for the benefit of the Executive, whether paid or payable or distributed or distributable pursuant to the terms of this Agreement or otherwise, calculated in a manner consistent with Section 280G of the Code and the applicable regulations thereunder (the “Aggregate Payments”), would be subject to the excise tax imposed by Section 4999 of the Code, then the Aggregate Payments shall be reduced (but not below zero) so that the sum of all of the Aggregate Payments shall be $1.00 less than the amount at which the Executive becomes subject to the excise tax imposed by Section 4999 of the Code; provided that such reduction shall only occur if it would result in the Executive receiving a higher After Tax Amount (as defined below) than the Executive would receive if the Aggregate Payments were not subject to such reduction. In such event, the Aggregate Payments shall be reduced in the following order, in each case, in reverse chronological order beginning with the Aggregate Payments that are to be paid the furthest in time from consummation of the transaction that is subject to Section 280G of the Code: (1) cash payments not subject to Section 409A of the Code; (2) cash payments subject to Section

6

409A of the Code; (3) equity-based payments and acceleration; and (4) non-cash forms of benefits; provided that in the case of all the foregoing Aggregate Payments all amounts or payments that are not subject to calculation under Treas. Reg. §1.280G-1, Q&A-24(b) or (c) shall be reduced before any amounts that are subject to calculation under Treas. Reg. §1.280G-1, Q&A-24(b) or (c).

(ii) For purposes of this Section 6(b), the “After Tax Amount” means the amount of the Aggregate Payments less all federal, state, and local income, excise and employment taxes imposed on the Executive as a result of the Executive’s receipt of the Aggregate Payments. For purposes of determining the After Tax Amount, the Executive shall be deemed to pay federal income taxes at the highest marginal rate of federal income taxation applicable to individuals for the calendar year in which the determination is to be made, and state and local income taxes at the highest marginal rates of individual taxation in each applicable state and locality, net of the maximum reduction in federal income taxes which could be obtained from deduction of such state and local taxes.

(iii) The determination as to whether a reduction in the Aggregate Payments shall be made pursuant to Section 6(b)(i) shall be made by a nationally recognized accounting firm selected by the Company (the “Accounting Firm”), which shall provide detailed supporting calculations both to the Company and the Executive within 15 business days of the Date of Termination, if applicable, or at such earlier time as is reasonably requested by the Company or the Executive. Any determination by the Accounting Firm shall be binding upon the Company and the Executive.

c) Definitions. For purposes of this Section 6, the following terms shall have the following meanings:

“Change in Control” shall mean any of the following:

(i) any “person,” as such term is used in Sections 13(d) and 14(d) of the Securities Exchange Act of 1934, as amended (the “Act”) (other than the Company, any of its subsidiaries, or any trustee, fiduciary or other person or entity holding securities under any employee benefit plan or trust of the Company or any of its subsidiaries), together with all “affiliates” and “associates” (as such terms are defined in Rule 12b-2 under the Act) of such person, shall become the “beneficial owner” (as such term is defined in Rule 13d-3 under the Act), directly or indirectly, of securities of the Company representing 50 percent or more of the combined voting power of the Company’s then outstanding securities having the right to vote in an election of the Board (“Voting Securities”) (in such case other than as a result of an acquisition of securities directly from the Company); or

(ii) the date a majority of the members of the Board is replaced during any 12-month period by directors whose appointment or election is not endorsed by a majority of the members of the Board before the date of the appointment or election; or

7

(iii) the consummation of (A) any consolidation or merger of the Company where the stockholders of the Company, immediately prior to the consolidation or merger, would not, immediately after the consolidation or merger, beneficially own (as such term is defined in Rule 13d-3 under the Act), directly or indirectly, shares representing in the aggregate more than 50 percent of the voting shares of the Company issuing cash or securities in the consolidation or merger (or of its ultimate parent corporation, if any), or (B) any sale or other transfer (in one transaction or a series of transactions contemplated or arranged by any party as a single plan) of all or substantially all of the assets of the Company.

Notwithstanding the foregoing, a “Change in Control” shall not be deemed to have occurred for purposes of the foregoing clause (i) solely as the result of an acquisition of securities by the Company which, by reducing the number of shares of Voting Securities outstanding, increases the proportionate number of Voting Securities beneficially owned by any person to 50 percent or more of the combined voting power of all of the then outstanding Voting Securities; provided, however, that if any person referred to in this sentence shall thereafter become the beneficial owner of any additional shares of Voting Securities (other than pursuant to a stock split, stock dividend, or similar transaction or as a result of an acquisition of securities directly from the Company) and immediately thereafter beneficially owns 50 percent or more of the combined voting power of all of the then outstanding Voting Securities, then a “Change in Control” shall be deemed to have occurred for purposes of the foregoing clause (i).

7. Section 409A.

a) Anything in this Agreement to the contrary notwithstanding, if at the time of the Executive’s separation from service within the meaning of Section 409A of the Code, the Company determines that the Executive is a “specified employee” within the meaning of Section 409A(a)(2)(B)(i) of the Code, then to the extent any payment or benefit that the Executive becomes entitled to under this Agreement on account of the Executive’s separation from service would be considered deferred compensation otherwise subject to the 20 percent additional tax imposed pursuant to Section 409A(a) of the Code as a result of the application of Section 409A(a)(2)(B)(i) of the Code, such payment shall not be payable and such benefit shall not be provided until the date that is the earlier of (A) six months and one day after the Executive’s separation from service, or (B) the Executive’s death. If any such delayed cash payment is otherwise payable on an installment basis, the first payment shall include a catch-up payment covering amounts that would otherwise have been paid during the six-month period but for the application of this provision, and the balance of the installments shall be payable in accordance with their original schedule.

b) All in-kind benefits provided and expenses eligible for reimbursement under this Agreement shall be provided by the Company or incurred by the Executive during the time periods set forth in this Agreement. All reimbursements shall be paid as soon as administratively practicable, but in no event shall any reimbursement be paid after the last day of the taxable year following the taxable year in which the expense was incurred. The amount of in-kind benefits provided or reimbursable expenses incurred in one taxable year shall not affect the in-kind benefits to be provided or the expenses eligible for reimbursement in any other taxable year (except for any lifetime or other aggregate limitation applicable to medical expenses). Such right to reimbursement or in-kind benefits is not subject to liquidation or exchange for another benefit.

8

c) To the extent that any payment or benefit described in this Agreement constitutes “non-qualified deferred compensation” under Section 409A of the Code, and to the extent that such payment or benefit is payable upon the Executive’s termination of employment, then such payments or benefits shall be payable only upon the Executive’s “separation from service.” The determination of whether and when a separation from service has occurred shall be made in accordance with the presumptions set forth in Treasury Regulation Section 1.409A-1(h).

d) The parties intend that this Agreement will be administered in accordance with Section 409A of the Code. To the extent that any provision of this Agreement is ambiguous as to its compliance with Section 409A of the Code, the provision shall be read in such a manner so that all payments hereunder comply with Section 409A of the Code, Each payment pursuant to this Agreement is intended to constitute a separate payment for purposes of Treasury Regulation Section 1.409A-2(b)(2). The parties agree that this Agreement may be amended, as reasonably requested by either party, and as may be necessary to fully comply with Section 409A of the Code and all related rules and regulations in order to preserve the payments and benefits provided hereunder without additional cost to either party.

e) The Company makes no representation or warranty and shall have no liability to the Executive or any other person if any provisions of this Agreement are determined to constitute deferred compensation subject to Section 409A of the Code but do not satisfy an exemption from, or the conditions of, such Section.

8. Restrictive Covenants.

a) Restrictive Covenant Agreement. The Executive acknowledges and agrees that in consideration of and in connection with the commencement of employment by the Company, he will enter into the Company’s Restrictive Covenant Agreement (the “Restrictive Covenant Agreement”). The Executive further acknowledges and agrees that he received the Restrictive Covenant Agreement more than ten (10) business days before the commencement of the Executive’s employment.

b) Third-Party Agreements and Rights. The Executive hereby confirms that, to the best of his knowledge, he is not bound by the terms of any agreement with any previous employer or other party that conflict with the terms of this Agreement. The Executive represents to the Company that the Executive’s execution of this Agreement, the Executive’s employment with the Company and the performance of the Executive’s proposed duties for the Company will not violate any existing obligations the Executive may have to any such previous employer or other party. In the Executive’s work for the Company, the Executive will not intentionally disclose or make use of any information in violation of any agreements with or rights of any such previous employer or other party, and the Executive will not bring to the premises of the Company any copies or other tangible embodiments of non-public information that is the property of any such previous employer or other party.

9

c) Litigation and Regulatory Cooperation. During and after the Executive’s employment, the Executive shall cooperate fully with the Company in the defense or prosecution of any claims or actions now in existence or which may be brought in the future against or on behalf of the Company which relate to events or occurrences that transpired while the Executive was employed by the Company. The Executive’s full cooperation in connection with such claims or actions shall include, but not be limited to, being available to meet with counsel to prepare for discovery or trial and to act as a witness on behalf of the Company at mutually convenient times. During and after the Executive’s employment, the Executive also shall cooperate fully with the Company in connection with any investigation or review of any federal, state or local regulatory authority as any such investigation or review relates to events or occurrences that transpired while the Executive was employed by the Company. The Company shall reimburse the Executive for any reasonable out-of-pocket expenses incurred in connection with the Executive’s performance of obligations pursuant to this Section 8(d); provided however, that if the Executive’s cooperation is required after the termination of Executive’s employment, the Company shall pay the Executive a per diem at his then-current daily rate for each day in which the Executive provides assistance, in addition to any such reimbursement.

d) Injunction. The Executive agrees that it would be difficult to measure any damages caused to the Company which might result from any breach by the Executive of the promises set forth in this Section 8, and that in any event money damages would be an inadequate remedy for any such breach. Accordingly, the Executive agrees that if the Executive breaches, or proposes to breach, any portion of this Agreement, the Company shall be entitled, in addition to all other remedies that it may have, to an injunction or other appropriate equitable relief to restrain any such breach without showing or proving any actual damage to the Company.

e) Protected Disclosures and Other Protected Actions. Nothing in this Agreement shall be interpreted or applied to prohibit the Executive from making any good faith report to any governmental agency or other governmental entity (a “Government Agency”) concerning any act or omission that the Executive reasonably believes constitutes a possible violation of federal or state law or making other disclosures that are protected under the anti-retaliation or whistleblower provisions of applicable federal or state law or regulation. In addition, nothing contained in this Agreement limits the Executive’s ability to communicate with any Government Agency or otherwise participate in any investigation or proceeding that may be conducted by any Government Agency, including the Executive’s ability to provide documents or other information, without notice to the Company. In addition, for the avoidance of doubt, pursuant to the federal Defend Trade Secrets Act of 2016, the Executive shall not be held criminally or civilly liable under any federal or state trade secret law or under this Agreement or the Restrictive Covenant Agreement for the disclosure of a trade secret that (a) is made (i) in confidence to a federal, state, or local government official, either directly or indirectly, or to an attorney; and (ii) solely for the purpose of reporting or investigating a suspected violation of law; or (b) is made in a complaint or other document filed in a lawsuit or other proceeding, if such filing is made under seal.

9. Consent to Jurisdiction. The parties hereby consent to the jurisdiction of the Superior Court of the Commonwealth of Massachusetts and the United States District Court for the District of Massachusetts. Accordingly, with respect to any such court action, the Executive (a) submits to the personal jurisdiction of such courts; (b) consents to service of process; and (c) waives any other requirement (whether imposed by statute, rule of court, or otherwise) with respect to personal jurisdiction or service of process.

10

10. Integration. This Agreement constitutes the entire agreement between the parties with respect to compensation, severance pay, benefits and accelerated vesting and supersedes in all respects all prior agreements between the parties concerning such the subject matter hereof, including without limitation any offer letter, employment agreement or severance agreement relating to the Executive’s employment relationship with the Company and/or the ending of that employment relationship. Notwithstanding the foregoing, the Restrictive Covenant Agreement, the Equity Documents, and any other agreement relating to confidentiality, noncompetition, nonsolicitation or assignment of inventions shall not be superseded by this Agreement and the Executive acknowledges and agrees that any such agreements remain in full force and effect.

11. Withholding. All payments made by the Company to the Executive under this Agreement shall be net of any tax or other amounts required to be withheld by the Company under applicable law.

12. Enforceability. If any portion or provision of this Agreement (including, without limitation, any portion or provision of any section of this Agreement) shall to any extent be declared illegal or unenforceable by a court of competent jurisdiction, then the remainder of this Agreement, or the application of such portion or provision in circumstances other than those as to which it is so declared illegal or unenforceable, shall not be affected thereby, and each portion and provision of this Agreement shall be valid and enforceable to the fullest extent permitted by law.

13. Survival. The provisions of this Agreement shall survive the termination of this Agreement and/or the termination of the Executive’s employment to the extent necessary to effectuate the terms contained herein.

14. Waiver. No waiver of any provision hereof shall be effective unless made in writing and signed by the waiving party. The failure of any party to require the performance of any term or obligation of this Agreement, or the waiver by any party of any breach of this Agreement, shall not prevent any subsequent enforcement of such term or obligation or be deemed a waiver of any subsequent breach.

15. Notices. Any notices, requests, demands and other communications provided for by this Agreement shall be sufficient if in writing and delivered in person or sent by a nationally recognized overnight courier service or by registered or certified mail, postage prepaid, return receipt requested, to the Executive at the last address the Executive has filed in writing with the Company or, in the case of the Company, at its main offices, attention of the Board.

16. Amendment. This Agreement may be amended or modified only by a written instrument signed by the Executive and by a duly authorized representative of the Company.

17. Effect on Other Plans and Agreements. An election by the Executive to resign for Good Reason under the provisions of this Agreement shall not be deemed a voluntary termination of employment by the Executive for the purpose of interpreting the provisions of any of the Company’s benefit plans, programs or policies. Nothing in this Agreement shall be construed to limit the rights of the Executive under the Company’s benefit plans, programs or policies except as otherwise provided in Section 8 hereof, and except that the Executive shall

11

have no rights to any severance benefits under any Company severance pay plan, offer letter or otherwise. In the event that the Executive is party to an agreement with the Company providing for payments or benefits under such agreement and this Agreement, the terms of this Agreement shall govern and the Executive may receive payment under this Agreement only and not both. Further, Section 5 and Section 6 of this Agreement are mutually exclusive and in no event shall the Executive be entitled to payments or benefits pursuant to Section 5 and Section 6 of this Agreement.

18. Governing Law. This is a Massachusetts contract and shall be construed under and be governed in all respects by the laws of the Commonwealth of Massachusetts, without giving effect to the conflict of laws principles of such Commonwealth. With respect to any disputes concerning federal law, such disputes shall be determined in accordance with the law as it would be interpreted and applied by the United States Court of Appeals for the First Circuit.

19. Assignment. Neither the Executive nor the Company may make any assignment of this Agreement or any interest in it, by operation of law or otherwise, without the prior written consent of the other; provided, however, that the Company may assign its rights and obligations under this Agreement (including the Restrictive Covenant Agreement) without the Executive’s consent to any affiliate or to any person or entity with whom the Company shall hereafter effect a reorganization, consolidate with, or merge into or to whom it transfers all or substantially all of its properties or assets; provided further that if the purchaser in any transaction involving the transfer of all or substantially all of the Company’s assets assumes this Agreement and the Executive accepts a position with the purchaser that is equivalent or better to his position immediately preceding such transaction, then the Executive shall not be entitled to any Severance Amount pursuant to Section 5 or any Change in Control Payment pursuant to Section 6. This Agreement shall inure to the benefit of and be binding upon the Executive and the Company, and each of the Executive’s and the Company’s respective successors, executors, administrators, heirs and permitted assigns.

20. Counterparts. This Agreement may be executed in any number of counterparts, each of which when so executed and delivered shall be taken to be an original; but such counterparts shall together constitute one and the same document.

21. Gender Neutral. Wherever used herein, a pronoun in the masculine gender shall be considered as including the feminine gender unless the context clearly indicates otherwise.

[Signature Page Follows]

12

IN WITNESS WHEREOF, the parties have executed this Agreement effective on the Effective Date.

13

Exhibit 99.2

Magenta Therapeutics Appoints Jason Ryan as Chief Operating and Financial Officer

Cambridge, MA – November 19th, 2018 – Magenta Therapeutics (NASDAQ: MGTA), a clinical-stage biotechnology company developing novel medicines to bring the curative power of bone marrow transplant to more patients, today announced that it has strengthened its executive team with the appointment of Jason Ryan as Chief Operating and Financial Officer, effective January 1, 2019.

“We are delighted to welcome Jason to Magenta at such an important time for the Company,” said Jason Gardner, D.Phil., chief executive officer and president, Magenta Therapeutics. “As we grow as a public company and advance our portfolio, Jason’s depth of experience in capital creation and allocation, operations and finance, and commercial planning will nicely complement the skills of our existing team and position us well to bring our first-in-class therapies to patients as efficiently and effectively as possible. I am looking forward to working closely with Jason in this high-impact role for our business.”

Mr. Ryan joins Magenta from Foundation Medicine, where he served as chief financial officer. During his tenure at Foundation, Mr. Ryan helped lead the company from early stage proof of concept to a global commercial organization. He was responsible for long-range planning and capital formation, and he played a key role in the company’s relationship with, and sale to, Roche in July 2018. He also worked closely with the company’s commercial leadership through several product launches and was deeply involved in Medicare and commercial payer reimbursement strategy and execution. Prior to that, Mr. Ryan held management positions for Taligen Therapeutics, Codon Devices and Genomics Collaborative, and began his career at Deloitte & Touche. Mr. Ryan holds a B.S. in economics from Bates College and an M.B.A. from Babson College.

About Magenta Therapeutics

Headquartered in Cambridge, Mass., Magenta Therapeutics is a clinical-stage biotechnology company developing novel medicines for patients with autoimmune diseases, blood cancers and genetic diseases. By creating a platform focused on critical areas of unmet need, Magenta Therapeutics is pioneering an integrated approach to allow more patients to receive one-time, curative therapies by making the process more effective, safer and easier.

Forward-Looking Statement

This press release may contain forward-looking statements, including express or implied statements regarding Magenta’s future expectations, plans and prospects, including projections regarding future revenues and financing performance, our long-term growth, the anticipated timing of our clinical trials and regulatory filings, the development of our product candidates and advancement of our preclinical programs, as well as other statements containing the words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” might,” “plan,” “potential,” “project,” “should,” target,” “will” or “would” and similar expressions that constitute forward-looking statements under the Private Securities Litigation Reform Act of 1995. Although Magenta’s forward-looking statements reflect the good faith judgment of its management, these statements are based only on facts and factors currently known by Magenta. As a result, you are cautioned not to rely on these forward-looking statements. These and other risks concerning Magenta’s programs and operations are described in additional detail in its registration statement on Form S-1, its Quarterly Report on Form 10-Q and its other filings made with the Securities and Exchange Commission from time to time. Any forward-looking statement made in this press release speaks only as of the date on which it is made. Magenta undertakes no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future developments or otherwise.

Contact

Magenta Therapeutics:

Manisha Pai, Vice President, Communications & Investor Relations

617-510-9193

mpai@magentatx.com