Sec Form 4 Filing - Quirk Michael C. @ Sage Therapeutics, Inc. - 2025-07-31

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Quirk Michael C. 2. Issuer Name and Ticker or Trading Symbol Sage Therapeutics, Inc. [ SAGE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) See Remarks (Last) (First) (Middle) C/O SAGE THERAPEUTICS, INC., 55 CAMBRIDGE PARKWAY 3. Date of Earliest Transaction (MM/DD/YY) 07/31/2025 (Street) CAMBRIDGE, MA02142 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 07/31/2025 D( 1 )( 2 ) 24,999 D 0 D Common Stock 07/31/2025 D 7,962 ( 3 ) D 0 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Stock Option (Right to Buy) $ 6.97 07/31/2025 D 36,000 ( 5 ) 01/16/2035 Common Stock 36,000 ( 5 ) 0 D Stock Option (Right to Buy) $ 7.86 07/31/2025 D 4,000 ( 5 ) 04/01/2035 Common Stock 4,000 ( 5 ) 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Quirk Michael C. C/O SAGE THERAPEUTICS, INC. 55 CAMBRIDGE PARKWAY CAMBRIDGE, MA02142 See Remarks Signatures /s/ Brandon Marsh, attorney in fact for Michael C. Quirk 07/31/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger (the "Merger Agreement"), dated as of June 13, 2025, among Sage Therapeutics, Inc. (the "Issuer"), Supernus Pharmaceuticals, Inc. ("Parent"), and Saphire, Inc., a wholly owned subsidiary of Parent ("Purchaser"), pursuant to which Purchaser completed a cash tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer, effective as of July 31, 2025 (the effective time of the merger, the "Effective Time"). At the Effective Time, each issued and outstanding Share was cancelled and converted into the right to receive (i) $8.50 per Share in cash (the "Closing Amount"), plus (ii) one contingent value right ("CVR") per Share, each without interest and subject to the withholding of applicable taxes. ( 2 )(Continued from footnote 1) Each CVR represents the right to receive up to $3.50 per Share in cash upon the satisfaction of specified milestones, as described in the Form 8-K filed by the Issuer with the Securities and Exchange Commission on June 16, 2025. ( 3 )Represents restricted stock units ("RSUs") granted to the Reporting Person. Each RSU represented a contingent right to receive one Share upon vesting of the RSU (a "Company RSU"). ( 4 )Pursuant to the Merger Agreement, at the Effective Time, each Company RSU reported in this Form 4 was deemed fully vested and cancelled and converted into the right to receive (i) a cash payment equal to the product of the Closing Amount multiplied by the number of Shares subject to such Company RSU, without interest and subject to the withholding of applicable taxes, plus (ii) one CVR for each Share subject to such Company RSU immediately prior to the Effective Time. ( 5 )Pursuant to the Merger Agreement, at the Effective Time, each option to purchase Shares (a "Company Option") then outstanding and unexercised, whether or not vested, which had a per Share exercise price less than the Closing Amount was deemed fully vested and cancelled and converted into the right to receive (i) a cash payment (without interest and subject to the withholding of applicable taxes) equal to the product of (a) the excess of the Closing Amount over the per Share exercise price of such Company Option, multiplied by (b) the total number of Shares subject to such Company Option immediately prior to the Effective Time, plus (ii) one CVR for each Share subject to such Company Option immediately prior to the Effective Time. Each Company Option, whether or not vested, which had a per Share exercise price greater than or equal to the Closing Amount was cancelled with no consideration payable in respect thereof.

Remarks: Chief Scientific Officer and Interim Head of R&D

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