Sec Form 4 Filing - Sinclair Andrew @ Sierra Oncology, Inc. - 2020-01-29

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 Sinclair Andrew 2. Issuer Name and Ticker or Trading Symbol Sierra Oncology, Inc. [ SRRA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O SIERRA ONCOLOGY, INC., 2150-885 WEST GEORGIA STREET 3. Date of Earliest Transaction (MM/DD/YY) 01/29/2020 (Street) VANCOUVER, A1V6C 3E8 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 01/29/2020 C 871,125 ( 3 ) A $ 0 ( 4 ) 876,542 ( 3 ) I See footnotes ( 1 ) ( 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 A Convertible Voting Preferred Stock ( 3 ) 01/29/2020 C 11,500 ( 5 ) ( 3 ) ( 3 ) Common Stock 871,125 ( 3 ) 0 I See footnotes ( 1 ) ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Sinclair Andrew C/O SIERRA ONCOLOGY, INC. 2150-885 WEST GEORGIA STREET VANCOUVER, A1V6C 3E8 X Signatures /s/ John Heard, as attorney-in-fact 01/31/2020 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The securities of Sierra Oncology, Inc. (the "Issuer") are held by Abingworth Bioventures VII, LP ("ABV VII"). Abingworth LLP is the investment manager of ABV VII and has been delegated with all investment and dispositive power over the securities held by ABV VII. Reporting Person is a Partner and Portfolio Manager of Abingworth LLP. ( 2 )An investment committee approves investment and voting decisions by a majority vote, and no individual member has the sole control or voting power over the shares held by ABV VII. From time to time, the investment committee may delegate investment and voting authority over certain securities held by ABV VII to employees of Abingworth LLP subject to the supervision and oversight of the investment committee, including any limits on such authority imposed by the investment committee in its discretion and the right of the investment committee to revoke such authority at any time. The Reporting Person disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein, if any. ( 3 )On January 22, 2020, a 1-for-40 reverse split of the Issuer's Common Stock (the "Reverse Split") was effected. These securities reflect the Reverse Split. ( 4 )Each share of Series A Convertible Voting Preferred Stock (the "Series A Preferred Stock") converted into 75.76 shares of the Issuer's Common Stock for no additional consideration, as adjusted for the Reverse Split, automatically upon the 5th trading date following the Issuer's announcement of receiving stockholder approval for the first reverse stock split of the Issuer following November 13, 2019. The Series A Preferred Stock has no expiration date. ( 5 )Consists of 11,500 shares of Series A Preferred Stock held by ABV VII which are convertible into an aggregate of 871,125 shares of Common Stock, as adjusted for the Reverse Split.

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