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 Global Blood Therapeutics, Inc. [GBT] 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) 05/17/2017 (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 04/11/2017   G V 50,000 (1) D $ 0 165,704 D (1)   Common Stock 04/18/2017   G V 1,708 (1) D $ 0 163,996 D (1)   Common Stock 05/17/2017   J(1)   1,000,000 D (2) 3,475,191 D (3)   Common Stock               193,677 (4) D (5)   Common Stock               181,721 (6) D (5)   Common Stock               259,454 (7) D (5)

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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
STARR KEVIN P 29 NEWBURY STREET, 3RD FLOOR BOSTON, MA 02116		X

Signatures

/s/ Kevin Gillis, Chief Financial Officer of TRV GP II, LLC, general partner of Third Rock Ventures GP II, L.P., general partner of Third Rock Ventures II, L.P.		05/17/2017
**Signature of Reporting Person		Date
/s/ Kevin Gillis, Chief Financial Officer of TRV GP II, LLC, general partner of Third Rock Ventures GP II, L.P.		05/17/2017
**Signature of Reporting Person		Date
/s/ Kevin Gillis, Chief Financial Officer of TRV GP II, LLC		05/17/2017
**Signature of Reporting Person		Date
/s/ Kevin Gillis by power of attorney for Mark Levin		05/17/2017
**Signature of Reporting Person		Date
/s/ Kevin Gillis by power of attorney for Kevin Starr		05/17/2017
**Signature of Reporting Person		Date
/s/ Kevin Gillis by power of attorney for Dr. Robert Tepper		05/17/2017
**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)	Reflects gifts by Mark Levin ("Levin"). The remaining shares are directly held by Levin.
(2)	Pursuant to a Rule 10b5-1 trading plan adopted by Third Rock Ventures II, L.P. ("TRV II"), Third Rock Ventures GP II, L.P. ("TRV GP II") and TRV GP II, LLC ("TRV GP II LLC"), TRV II distributed on May 17, 2017, for no consideration, 1,000,000 shares of Common Stock of the Issuer (the "Shares") to its limited partners and to TRV GP II, the general partner of TRV II, representing each such partner's pro rata interest in such Shares. On the same date, TRV GP II distributed, for no consideration, the Shares it received in the distribution by TRV II to its partners, representing each such partner's pro rata interest in such Shares. All of the aforementioned distributions were made in accordance with the exemptions afforded by Rules 16a-13 and 16a-9 of the Securities Exchange Act of 1934, as amended.
(3)	These shares are directly held by TRV II. The general partner of TRV II is TRV GP II. The general partner of TRV GP II is TRV GP II LLC. The individual managers of TRV GP II LLC are Levin, Kevin Starr ("Starr") and Dr. Robert Tepper ("Tepper"). Each of TRV GP II, TRV GP II LLC, Levin, Starr and Tepper disclaims beneficial ownership of the shares except to the extent of its or his pecuniary interest therein, if any, and this report shall not be deemed an admission that it or he is the beneficial owner of such shares.
(4)	These shares are directly held by Levin. Includes shares received in the distributions described in footnote (2) above.
(5)	In addition to the reported shares, Third Rock Ventures III, L.P. ("TRV III") directly holds 285,713 shares of Common Stock of the Issuer. The general partner of TRV III is Third Rock Ventures GP III, L.P. ("TRV GP III"). The general partner of TRV GP III is TRV GP III, LLC ("TRV GP III LLC"). The individual managers of TRV GP III LLC are Levin, Starr and Tepper. Each of TRV GP III, TRV GP III LLC, Levin, Starr and Tepper disclaims beneficial ownership of the shares except to the extent of its or his pecuniary interest therein, if any, and this report shall not be deemed an admission that it or he is the beneficial owner of such shares.
(6)	These shares are directly held by Starr. Includes Shares received in the distributions described in footnote (2) above.
(7)	These shares are directly held by Tepper. Includes Shares received in the distributions described in footnote (2) above.

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