Sec Form 4 Filing - RA CAPITAL MANAGEMENT, LLC @ G1 Therapeutics, Inc. - 2017-05-22

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

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person RA CAPITAL MANAGEMENT, LLC 2. Issuer Name and Ticker or Trading Symbol G1 Therapeutics, Inc. [ GTHX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) X __ Other (specify below) Fmr 10% Owner See Footnote (2) (Last) (First) (Middle) 20 PARK PLAZA, SUITE 1200, 3. Date of Earliest Transaction (MM/DD/YY) 05/22/2017 (Street) BOSTON, MA02116 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (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 05/22/2017 C 1,723,304 A 1,723,304 I See footnotes ( 1 ) ( 2 ) Common Stock 05/22/2017 C 560,940 ( 3 ) A 2,284,244 I See footnotes ( 2 ) Common Stock 05/22/2017 P 400,000 ( 6 ) A $ 15 2,684,244 ( 7 ) I See footnote ( 2 )

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 Series B Preferred Stock ( 4 ) 05/22/2017 C 5,169,916 ( 8 ) ( 4 ) ( 4 ) Common Stock 1,723,304 $ 1.4507 0 I See footnotes ( 1 ) ( 2 ) Series C Preferred Stock ( 5 ) 05/22/2017 C 1,682,822 ( 9 ) ( 5 ) ( 5 ) Common Stock 560,940 ( 3 ) $ 2.9712 0 I See footnotes ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other RA CAPITAL MANAGEMENT, LLC 20 PARK PLAZA, SUITE 1200 BOSTON, MA02116 Fmr 10% Owner See Footnote (2) RA Capital Healthcare Fund LP C/O RA CAPITAL MANAGEMENT, LLC 20 PARK PLAZA, SUITE 1200 BOSTON, MA02116 Fmr 10% Owner See Footnote (2) Kolchinsky Peter C/O RA CAPITAL MANAGEMENT, LLC 20 PARK PLAZA, SUITE 1200 BOSTON, MA02116 Fmr 10% Owner See Footnote (2) Signatures /s/ Peter Kolchinsky, Manager of RA Capital Management, LLC 05/24/2017 Signature of Reporting Person Date /s/ Peter Kolchinsky, individually 05/24/2017 Signature of Reporting Person Date /s/ Peter Kolchinsky, Manager of RA Capital Management, LLC, the General Partner of RA Capital Healthcare Fund, L.P. 05/24/2017 Signature of Reporting Person Date

Explanation of Responses:

( 1 )These securities are held by RA Capital Healthcare Fund, L.P. (the "Fund"). ( 2 )RA Capital Management, LLC ("Adviser") is the general partner of the Fund and the investment adviser for a separately managed account (the "Account"). Peter Kolchinsky is the manager of Adviser. Adviser and Dr. Kolchinsky may be deemed indirect beneficial owners of the reported securities and disclaim beneficial ownership thereof: (A) in reliance on Rule 16a-1(a)(1)(v) and (vii); and (B) held by Fund, for purposes of Rule 16a-1(a)(2), except to the extent of their pecuniary interest therein. Adviser and Dr. Kolchinsky have no pecuniary interest in the reported securities held in the Account and disclaim: (A) beneficial ownership thereof for purposes of Rule 16a-1(a)(2); and (B) any filing obligations under Section 16 other than as a director by deputization and a director, respectively. This Form 4 shall not be construed as an admission that Adviser or Dr. Kolchinsky is or was under Section 16(a), or otherwise, the beneficial owner of any of the reported securities. ( 3 )These securities include 453,801 shares held by the Fund and 107,139 shares held in the Account. ( 4 )Each share of the Series B Preferred Stock converted into Common Stock on a 1-for-3 basis automatically upon the closing of the Issuer's initial public offering, and had no expiration date. ( 5 )Each share of the Series C Preferred Stock converted into Common Stock on a 1-for-3 basis automatically upon the closing of the Issuer's initial public offering, and had no expiration date. ( 6 )These securities include 322,895 shares held by the Fund and 77,105 shares held in the Account. ( 7 )These securities include 2,500,000 shares held by the Fund and 184,244 shares held in the Account. ( 8 )These shares are held by the Fund. ( 9 )These securities include 1,361,403 shares held by the Fund and 321,419 shares held in the Account.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* 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).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.