Sec Form 4 Filing - Burow Kristina @ Unity Biotechnology, Inc. - 2019-06-20

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 Burow Kristina 2. Issuer Name and Ticker or Trading Symbol Unity Biotechnology, Inc. [ UBX] 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 UNITY BIOTECHNOLOGY, INC., 3280 BAYSHORE BOULEVARD 3. Date of Earliest Transaction (MM/DD/YY) 06/20/2019 (Street) BRISBANE, CA94005 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 8,365,764 I See Footnotes ( 1 ) ( 3 ) Common Stock 1,682,417 I See Footnotes ( 2 ) ( 3 ) Common Stock 79,096 I See Footnote ( 4 ) Common Stock 33,898 I See Footnote ( 5 )

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 Stock Option (Right to Buy) $ 9 06/20/2019 A 25,000 ( 6 ) 06/19/2029 Common Stock 25,000 $ 0 25,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Burow Kristina C/O UNITY BIOTECHNOLOGY, INC. 3280 BAYSHORE BOULEVARD BRISBANE, CA94005 X Signatures /s/ Tamara L. Tompkins, Attorney-in-Fact for Kristina Burow 06/24/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The shares are directly held by ARCH Venture Fund VII, L.P. ("ARCH VII"). ARCH Venture Partners VII, L.P. (the "GPLP"), as the sole general partner of ARCH VII, may be deemed to beneficially own certain of the shares held by ARCH VII. ARCH Venture Partners VII, LLC ("GPLLC"), as the sole general partner of GPLP, may be deemed to beneficially own the shares held by GPLP. GPLP and GPLLC disclaim beneficial ownership of such shares except to the extent of any pecuniary interest therein. ( 2 )The shares are directly held by ARCH Venture Fund VIII Overage, L.P. ("ARCH Overage"). ARCH Venture Partners VIII, LLC (the "AVP GPLLC"), as the sole general partner of ARCH Overage, may be deemed to beneficially own the shares held by ARCH Overage. AVP GPLLC disclaims beneficial ownership of such shares except to the extent of any pecuniary interest therein. ( 3 )The managing directors of GPLLC and AVP GPLLC are Keith Crandell and Clinton Bybee, and they may be deemed to beneficially own the shares held by ARCH Fund VII and ARCH Overage. Messrs. Crandell and Bybee disclaim beneficial ownership of such shares, except to the extent of any pecuniary interest therein. Director Kristina Burow owns an interest in ARCH Partners VII and AVP GPLLC but does not have voting or investment control over the shares held by ARCH Fund VII or ARCH Overage and disclaims beneficial ownership of such shares, except to the extent of any pecuniary interest therein. ( 4 )The shares are directly held by Backes & Burow 2012 Revocable Trust, in which the Reporting Person holds a controlling interest. ( 5 )The shares are directly held by the Reporting Person's spouse. ( 6 )The underlying shares subject to the option vest and become exercisable as to 100% of the total number of shares subject to the option on the earlier of (i) the one-year anniversary measured from June 20, 2019 or (ii) the date of the 2020 Annual Meeting of the Issuer's stockholders, assuming continuous service as a Non-Employee Director until such vesting date.

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).

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