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
                                                                                  
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940
                      
1. Name and Address of Reporting Person * Kowalski Mark 2. Issuer Name and Ticker or Trading Symbol Sierra Oncology, Inc. [ SRRA ] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable)_____ Director                    _____ 10% Owner
__X__ Officer (give title below)    _____ Other (specify below)
Chief Medical Officer
(Last)         (First)         (Middle)
C/O SIERRA ONCOLOGY, INC., 2150 885 WEST GEORGIA ST.
3. Date of Earliest Transaction (MM/DD/YYYY)
2/25/2020
(Street)
VANCOUVER, A1 V6C 3E8
(City)       (State)       (Zip)
4. If Amendment, Date Original Filed (MM/DD/YYYY)
 
6. Individual or Joint/Group Filing (Check Applicable Line) _X _ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Trans. Date 2A. Deemed Execution Date, if any 3. Trans. 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

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Trans. Date 3A. Deemed Execution Date, if any 4. Trans. 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 7. Title and Amount of Securities Underlying Derivative Security
(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)  $13.31  2/25/2020    A     75030       (1) 2/25/2030  Common Stock  75030  $0.00  75030  D   

Explanation of Responses:
(1)  The option vests as to 25% of the total shares on February 25, 2021, and then 2.0833% of the total shares vest monthly thereafter, with 100% of the total shares vested on February 25, 2024, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

Reporting Owners
Reporting Owner Name / Address
Relationships
Director 10% Owner Officer Other
Kowalski Mark
C/O SIERRA ONCOLOGY, INC.
2150 885 WEST GEORGIA ST.
VANCOUVER, A1 V6C 3E8


Chief Medical Officer

Signatures
/s/ Sukhi Jagpal as attorney-in-fact for Mark Kowalski, M.D., Ph.D. 2/27/2020
**Signature of Reporting Person Date
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