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 OF SECURITIES 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 * Third Rock Ventures II, L.P.   2. Issuer Name and Ticker or Trading Symbol Sage Therapeutics, Inc. [SAGE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O THIRD ROCK VENTURES, LLC, 29 NEWBURY STREET, 3RD FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 08/18/2015 (Street) BOSTON, MA 02116 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ 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 (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 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 08/18/2015   J(1)   2,330,157 D $ 0 6,442,916 D (2)   Common Stock 08/18/2015   J(3)   150,546 A $ 0 150,546 D (4)   Common Stock 08/18/2015   J(5)   150,546 D $ 0 0 D (4)   Common Stock 08/18/2015   J(6)   21,910 A $ 0 49,240 D   Common Stock 08/18/2015   J(7)   21,910 A $ 0 49,241 D

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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 (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

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 (Month/Day/Year)

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

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Third Rock Ventures II, L.P. C/O THIRD ROCK VENTURES, LLC 29 NEWBURY STREET, 3RD FLOOR BOSTON, MA 02116		X
Third Rock Ventures GP II, L.P. 29 NEWBURY STREET, 3RD FLOOR BOSTON, MA 02116		X
TRV GP II, LLC 29 NEWBURY STREET, 3RD FLOOR BOSTON, MA 02116		X
LEVIN MARK J 29 NEWBURY STREET, 3RD FLOOR BOSTON, MA 02116		X
TEPPER ROBERT I 29 NEWBURY STREET, 3RD FLOOR BOSTON, MA 02116		X

Signatures

/s/ Third Rock Ventures II, L.P. by Third Rock Ventures GP II, L.P. its general partner by TRV GP II, LLC its general partner		08/18/2015
**Signature of Reporting Person		Date
/s/ Third Rock Ventures GP II, L.P. by TRV GP II, LLC its general partner		08/18/2015
**Signature of Reporting Person		Date
/s/ TRV GP II, LLC		08/18/2015
**Signature of Reporting Person		Date
/s/ Kevin Gillis by power of attorney for Mark Levin		08/18/2015
**Signature of Reporting Person		Date
/s/ Kevin Gillis by power of attorney for Dr. Robert Tepper		08/18/2015
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Distribution of shares in kind by Third Rock Ventures II, L.P. ("TRV") on a pro rata basis to its partners.
(2)	The shares are directly held by Third Rock Ventures II, L.P. ("TRV"). The general partner of TRV is Third Rock Ventures GP II, L.P. ("TRV GP"). The general partner of TRV GP is TRV GP II, LLC ("TRV GP LLC"). The individual managers of TRV GP LLC are Mark Levin ("Levin"), Kevin Starr ("Starr") and Dr. Robert Tepper ("Tepper") and, as such, each of TRV GP, TRV GP LLC, Levin, Starr and Tepper exercises shared voting and investment power over the shares held of record by TRV. Each of the Reporting Persons disclaims beneficial ownership of the shares except to the extent of their pecuniary interest therein, if any.
(3)	TRV GP received shares distributed in kind by TRV on a pro rata basis to its partners.
(4)	The shares are directly held by TRV GP. As such, each of TRV GP LLC, Levin, Starr and Tepper exercises shared voting and investment power over the shares held of record TRV GP. Each of the Reporting Persons disclaims beneficial ownership of the shares except to the extent of its pecuniary interest therein, if any.
(5)	Distribution of shares in kind by TRV GP on a pro rata basis to its partners.
(6)	Levin received shares distributed in kind by TRV GP on a pro rata basis to its partners.
(7)	Tepper received shares distributed in kind by TRV GP on a pro rata basis to its partners.

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