Sec Form 3 Filing - Aggarwal Gaurav @ Sierra Oncology, Inc. - 2019-11-22

FORM 3 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 Aggarwal Gaurav 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 X __ 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) 11/22/2019 (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

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 ( 1 ) ( 2 ) ( 1 )( 2 ) ( 1 )( 2 ) Common Stock 58,215,390 ( 1 ) ( 2 ) ( 3 ) I See footnotes ( 3 ) Series A Warrants $ 0.33 ( 4 )( 5 ) ( 4 )( 5 ) Common Stock 58,215,390 ( 3 ) ( 4 ) ( 5 ) I See footnotes ( 3 ) Series B Warrants $ 0.33 ( 6 ) ( 6 ) Common Stock 19,211,079 ( 3 ) ( 6 ) I See footnotes ( 3 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Aggarwal Gaurav C/O SIERRA ONCOLOGY, INC. 2150 - 885 WEST GEORGIA STREET VANCOUVER, A1V6C 3E8 X X Signatures /s/ Sukhi Jagpal as attorney-in-fact for Gaurav Aggarwal 11/26/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Each share of Series A Convertible Voting Preferred Stock (the "Series A Preferred Stock") will convert into 3,030 shares of the Issuer's Common Stock (a) at the option of the holder and (b) 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, provided that, the Issuer will not effect any conversion, and the holder will not have the right to convert, subject to certain exceptions, the Series A Preferred Stock for shares of Common Stock if, as a result of such conversion, the holder, together with its affiliates and other attribution parties, would own more than 9.99% of the total number of shares of Common Stock then issued and outstanding, which percentage may be changed at the holder's election to a lower percentage at any time or to a higher percentage upon 61 days' notice to the Issuer, (continued) ( 2 )(continued from footnote 1) and provided further that such limitation on exercise will automatically increase to 19.99% of the total number of shares of Common Stock then issued and outstanding during the period that any employee, manager, partner, managing director or affiliate of such holder is then serving on the Issuer's board of directors. As the Reporting Person is a member of the Issuer's board of directors and affiliated with Vivo Opportunity Fund, L.P., Vivo Capital Fund IX, L.P., Vivo Ventures Fund VII, L.P. and Vivo Ventures VII Affiliates Fund, L.P., the conversion limitation for Series A Preferred Stock held by these funds is 19.99%. The Series A Preferred Stock has no expiration date. ( 3 )The Reporting Person's beneficial ownership of the Issuer's Common Stock is comprised of 19,213 shares of Series A Preferred Stock, 58,215,390 Series A Warrants and 58,215,390 Series B Warrants held of record by Vivo Opportunity Fund, L.P. The Reporting Person is a managing member of Vivo Opportunity, LLC, which is the general partner of Vivo Opportunity Fund, L.P. The Reporting Person may be deemed to share voting and dispositive power over the securities held by Vivo Opportunity Fund, L.P. with four other managing members of Vivo Opportunity, LLC. The Reporting Person disclaims beneficial ownership over such securities except to the extent of his pecuniary interest therein, and the inclusion of such securities in this report shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 or for any other purposes. ( 4 )Each Series A Warrant will be exercisable for one share of Common Stock. The Series A Warrants are exercisable on the first trading day following the date the Issuer obtains stockholder approval of an amendment to its certificate of incorporation increasing the aggregate number of authorized shares of its Common Stock, such that the Issuer shall have sufficient authorized but unissued shares of Common Stock, solely for the purpose of enabling the Issuer to issue shares of its Common Stock upon exercise of the Series A Warrants and the Series B Warrants (the "Warrant Exercise Date"), provided that, at each holder's election, the holder will be prohibited, subject to certain exceptions, from exercising the Series A Warrant for shares of Common Stock if, as a result of such exercise, the holder, together with its affiliates and other attribution parties, would own more than 9.99% of the total number of shares of Common Stock then issued and outstanding, (continued) ( 5 )(continued from footnote 4), which percentage may be changed at the holder's election to a lower percentage at any time or to a higher percentage upon 61 days' notice to the Issuer. Each Series A Warrant will expire five years from the date it first becomes exercisable. ( 6 )Each Series B Warrant will be exercisable for 0.33 shares of Common Stock. The Series B Warrants are exercisable on the Warrant Exercise Date, provided that, at each holder's election, the holder will be prohibited, subject to certain exceptions, from exercising the Series B Warrant for shares of Common Stock if, as a result of such exercise, the holder, together with its affiliates and other attribution parties, would own more than 9.99% of the total number of shares of Common Stock then issued and outstanding, which percentage may be changed at the holder's election to a lower percentage at any time or to a higher percentage upon 61 days' notice to the Issuer. Each Series B warrant will expire on the 75th day anniversary of the Issuer's announcement of top-line data from MOMENTUM, its planned Phase 3 clinical trial of momelotinib for patients with myelofibrosis.

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