EX-10.21



 Exhibit 10.21 

SEVERANCE AND CHANGE IN CONTROL AGREEMENT 

This Severance and Change in Control Agreement (this “Agreement”) is made as of September 30, 2014 by and between Sage Therapeutics,
Inc., a Delaware corporation (the “Company”), and Kimi Iguchi (the “Executive”) and shall become effective on the date of the effectiveness of the Company’s registration statement on Form S-1 under the Securities Exchange
Act of 1933, as amended. 
 1. Purpose. The Company considers it essential to the best interests of its stockholders to
promote and preserve the continuous employment of key management personnel. The Board of Directors of the Company (the “Board”) recognizes that, as is the case with many corporations, the possibility of a Change in Control (as defined in
Section 2 hereof) exists and that such possibility, and the uncertainty and questions that it may raise among management, may result in the departure or distraction of key management personnel to the detriment of the Company and its
stockholders. Therefore, the Board has determined that appropriate steps should be taken to reinforce and encourage the continued attention and dedication of members of the Company’s key management, including the Executive, to their assigned
duties without distraction, including in the face of potentially disturbing circumstances arising from the possibility of a Change in Control. Nothing in this Agreement shall be construed to affect the at-will nature of the employment relationship,
the Executive shall not have any right to be retained in the employ of the Company. 
 2. Change in Control. A
“Change in Control” shall be deemed to have occurred upon the occurrence of any one of the following events: (a) the sale of all or substantially all of the assets of the Company on a consolidated basis to an unrelated person or
entity, (b) a merger, reorganization or consolidation pursuant to which the holders of the Company’s outstanding voting power and outstanding stock immediately prior to such transaction do not own a majority of the outstanding voting power
and outstanding stock or other equity interests of the resulting or successor entity (or its ultimate parent, if applicable) immediately upon completion of such transaction, (c) the sale of all of the stock of the Company to an unrelated
person, entity or group thereof acting in concert, or (d) any other transaction in which the owners of the Company’s outstanding voting power immediately prior to such transaction do not own at least a majority of the outstanding voting
power of the Company or any successor entity immediately upon completion of the transaction other than as a result of the acquisition of securities directly from the Company. 

3. Terminating Event. 

A “Terminating Event” shall mean any of the events provided in this Section 3: 

(a) Termination by the Company. Termination by the Company of the employment of the Executive with the Company for any
reason other than for Cause, death or Disability. For purposes of this Agreement, “Cause” shall mean, as determined by the Company in good faith: 







 (i) the indictment the Executive of any felony, any crime involving the Company,
or any crime involving fraud, moral turpitude or dishonesty; 
 (ii) any unauthorized use or disclosure of the Company’s
proprietary information which has an adverse effect on the Company’s business or reputation. As used in this paragraph, “Proprietary Information” means any information in whatever form, tangible or intangible, related to the business
of the Company unless the information is publicly available in hard copy or electronic format, through lawful means; 
 (iii)
any intentional misconduct or gross negligence on the Executive’s part which has a materially adverse effect on the Company’s business or reputation; or 

(iv) the Executive’s repeated and willful failure to perform the duties, functions and responsibilities of the
Executive’s position after a written warning from the Company. 
 A Terminating Event shall not be deemed to have occurred pursuant to
this Section 3(a) solely as a result of the Executive becoming an employee of any direct or indirect successor to the business or assets of the Company, rather than continuing as an employee of the Company following a Change in Control. For
purposes hereof, the Executive will be considered “Disabled” if, as a result of the Executive’s incapacity due to physical or mental illness, the Executive shall have been absent from his duties to the Company on a full-time basis for 180 calendar days in the aggregate in any 12-month period. 
 (b)
Termination by the Executive for Good Reason. Termination by the Executive of the Executive’s employment with the Company for 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, defined as miles or more, in the geographic location at which the Executive is required to provides
services to the Company, not including business travel and short-term assignments; or 
 (iv) a material breach of this
Agreement by the Company. 
 “Good Reason Process” shall mean that (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 

  
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the condition; (iv) notwithstanding such efforts, the Good Reason condition continues to exist; and (v) the Executive provides a Notice of Termination to the Company 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. 

4. Change in Control Payment. In the event a Terminating Event occurs on or within the 12 months immediately after a Change in
Control (such 12-month period, the “Change in Control Period”), subject to the Executive signing a separation agreement containing, among other provisions, a general release of claims in favor of the Company and related persons and
entities, confidentiality, return of property and non-disparagement, in the form attached hereto as Attachment A (the “Separation Agreement and Release”) and the Separation Agreement and Release becoming irrevocable, all within 60 days
after the Date of Termination or end of the Cure Period , the following shall occur 
 (a) the Company shall pay to
the Executive an amount equal to the sum of (i) 9 months of the Executive’s annual base salary in effect immediately prior to the Terminating Event (or the Executive’s annual base salary in effect immediately prior to the Change in
Control, if higher), and (ii) a pro rata portion of the Executive’s target bonus for the fiscal year in which the termination of employment occurs, determined by multiplying the target bonus by a fraction, the numerator of which shall be
the number of days during the fiscal year in which the Executive was employed by the Company and the denominator of which shall be 365; 

(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 to the Executive a lump sum payment, in an amount equal to 12 times the monthly employer contribution that the Company would have made to provide health insurance to the Executive if the
Executive had remained employed by the Company; 
 (c) notwithstanding anything to the contrary in any applicable option
agreement or stock-based award agreement, all stock options and other stock-based awards with time-based vesting held by the Executive shall immediately accelerate and become fully exercisable and nonforfeitable as of the Executive’s Date of
Termination conditioned upon the Separation Agreement and Release becoming irrevocable; and 
 (d) the amounts payable under
this Section 4 shall be paid out in a lump sum 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 amounts shall be paid in
the second calendar year by the last day of such 60-day period. All other wages earned, including, but not limited to, accrued vacation, to the Date of Termination shall be paid on the Date of Termination. 

5. Severance Outside the Change in Control Period. In the event a Terminating Event occurs at any time other than during the
Change in Control Period, subject to the Executive signing the Separation Agreement and Release and the Separation Agreement and Release becoming irrevocable, all within 60 days after the Date of Termination, the following shall occur: 

  
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 (a) the Company shall pay to the Executive an amount equal to 12 months times the
Executive’s annual base salary in effect immediately prior to the Terminating Event; 
 (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 to the Executive a monthly cash payment for 12 months in an amount equal to the
monthly employer contribution that the Company would have made to provide health insurance to the Executive if the Executive had remained employed by the Company; and 

(c) the amounts payable under this Section 5 shall be paid out in substantially equal installments in accordance with the
Company’s payroll practice over 12 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 1.409A-2(b)(2). 

6. Additional Limitation. 

(a) 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 “Compensatory Payments”), would be subject to the excise tax imposed by Section 4999 of the Internal Revenue Code of 1986, as amended (the “Code”), (or any successor provision),
then the Compensatory Payments shall be reduced so that the sum of all of the Compensatory 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 (or any
successor provision); 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 Compensatory Payments were not subject to such
reduction. In such event, the Compensatory Payments shall be reduced in the following order, in each case, in reverse chronological order beginning with the Compensatory Payments that are to be paid the furthest in time from consummation of the
transaction that is subject to Section 280G of the Code: (i) cash payments not subject to Section 409A of the Code; (ii) cash payments subject to Section 409A of the Code; (iii) equity-based payments and acceleration;
and (iv) non-cash forms of benefits; provided that in the case of all the foregoing Compensatory 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). 
 (b) For
purposes of this Section 6, the “After Tax Amount” means the amount of the Compensatory 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 Compensatory Payments. For purposes of determining the After Tax Amount, the Executive shall be deemed to 

  
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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. 

(c) The determination as to whether a reduction in the Compensatory Payments shall be made pursuant to Section 6(a) shall
be made by an 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. 

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 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. 
 (b) 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. 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. 

(c) 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. Such right to reimbursement or in-kind benefits is not subject to liquidation or exchange for another benefit. 

  
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 (d) 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). 
 (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. Term. This Agreement shall take effect on the date first set forth above and shall terminate upon the earlier of (a) the
termination of the Executive’s employment with the Company for any reason other than the occurrence of a Terminating Event, or (b) the date all amounts have been paid to the Executive upon a Terminating Event pursuant to Section 4 or
Section 5 hereof. 
 9. 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. 
 10. Notice and Date
of Termination. 
 (a) Notice of Termination. After a Change in Control and during the term of this Agreement,
any purported termination of the Executive’s employment (other than by reason of death) shall be communicated by written Notice of Termination from one party hereto to the other party hereto in accordance with this Section 10. 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 Executive’s Disability or by the Company for Cause, the date on which Notice of Termination is given; (iii) if the
Executive’s employment is terminated by the Company without Cause the date on which a Notice of Termination is given; (iv) if the Executive’s employment is terminated by the Executive 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 with 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. 
 11. No Mitigation. The Company agrees that, if the Executive’s employment by the Company is
terminated during the term of this Agreement, the Executive is not required to seek 

  
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other employment or to attempt in any way to reduce any amounts payable to the Executive by the Company pursuant to Section 4 or Section 5 hereof. Further, the amount of any payment
provided for in this Agreement shall not be reduced by any compensation earned by the Executive as the result of employment by another employer. 

12. Consent to Jurisdiction. The parties hereby consent to the jurisdiction of the Superior Court or 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.  

13. Integration. This Agreement constitutes the entire agreement between the parties with respect to severance pay, benefits and
accelerated vesting in connection with any termination of employment, to the extent inconsistent with any prior agreements supersedes the inconsistent provisions of such prior agreements between the parties concerning such subject matter, including
without limitation any provisions of any offer letter or employment agreement relating to severance pay or benefits in connection with the ending of Executive’s employment relationship with the Company. In the interest of clarity, any agreement
relating to confidentiality, noncompetition, nonsolicitation or assignment of inventions shall not be affected by the Agreement.  

14. Successor to the Executive. This Agreement shall inure to the benefit of and be enforceable by the Executive’s personal
representatives, executors, administrators, heirs, distributees, devisees and legatees. In the event of the Executive’s death after a Terminating Event but prior to the completion by the Company of all payments due him under this Agreement, the
Company shall continue such payments to the Executive’s beneficiary designated in writing to the Company prior to his death (or to his estate, if the Executive fails to make such designation). 

15. 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. 

16. 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. 
 17. 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 of by registered or certified mail, postage prepaid, return 

  
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receipt requested, to the Executive at the last address the Executive has filed in writing with the Company, or to the Company at its main office, attention of the Board of Directors. 

18. 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. 
 19. 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 6 hereof, and except that the Executive shall 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 Executive may receive payment under this Agreement only and not both. Further, Section 4 and Section 5 of this Agreement are mutually exclusive and in no event shall Executive be entitled to
payments or benefits pursuant to Section 4 and Section 5 of this Agreement.  
 20. 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. 

21. Successor to Company. The Company shall require any successor (whether direct or indirect, by purchase, merger,
consolidation or otherwise) to all or substantially all of the business or assets of the Company expressly to assume and agree to perform this Agreement to the same extent that the Company would be required to perform it if no succession had taken
place. Failure of the Company to obtain an assumption of this Agreement at or prior to the effectiveness of any succession shall be a material breach of this Agreement.  

22. 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. 
 23. 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.  

[Remainder of Page Intentionally Left Blank] 

  
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 IN WITNESS WHEREOF, the parties have executed this Agreement effective on the date and
year first above written. 
  

			
	SAGE THERAPEUTICS, INC.
		
	By:		/s/ Jeffrey M. Jonas
			 Name: Jeffrey M. Jonas
 Title: Chief
Executive Officer



  
  

	
	
	/s/ Kimi Iguchi
	Kimi Iguchi


  
 [Signature Page to Severance and
Change in Control Agreement]