Sec Form 4 Filing - Flagship Ventures Fund V General Partner LLC @ Sana Biotechnology, Inc. - 2023-06-06

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 Flagship Ventures Fund V General Partner LLC 2. Issuer Name and Ticker or Trading Symbol Sana Biotechnology, Inc. [ SANA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 55 CAMBRIDGE PARKWAY, SUITE 800E 3. Date of Earliest Transaction (MM/DD/YY) 06/06/2023 (Street) CAMBRIDGE, MA02142 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 06/06/2023 S 181,461 D $ 6.3061 ( 1 ) 10,920,533 I By Flagship Ventures Fund V, L.P. ( 2 ) Common Stock 06/06/2023 S 22,297 D $ 6.3061 ( 1 ) 1,403,037 I By Flagship V VentureLabs Rx Fund, L.P. ( 3 ) Common Stock 06/07/2023 S 177,240 D $ 6.2397 ( 4 ) 10,743,293 I By Flagship Ventures Fund V, L.P. ( 2 ) Common Stock 06/07/2023 S 22,760 D $ 6.2397 ( 4 ) 1,380,277 I By Flagship V VentureLabs Rx Fund, L.P. ( 3 ) Common Stock 11,441,326 I By Flagship VentureLabs V, LLC ( 5 ) Common Stock 9,725,122 I By Flagship Pioneering Fund VI, L.P. ( 6 )

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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Flagship Ventures Fund V General Partner LLC 55 CAMBRIDGE PARKWAY SUITE 800E CAMBRIDGE, MA02142 X Flagship Ventures Fund V, L.P. 55 CAMBRIDGE PARKWAY, SUITE 800E CAMBRIDGE, MA02142 X Flagship V VentureLabs Rx Fund, L.P. 55 CAMBRIDGE PARKWAY, SUITE 800E CAMBRIDGE, MA02142 X AFEYAN NOUBAR 55 CAMBRIDGE PARKWAY, SUITE 800E CAMBRIDGE, MA02142 X Signatures Flagship Ventures Fund V General Partner LLC, By: /s/ Noubar B. Afeyan, Ph.D., Title: Manager 06/08/2023 Signature of Reporting Person Date Flagship Ventures Fund V, L.P., By: Flagship Ventures Fund V General Partner LLC, its General Partner, By: /s/ Noubar B. Afeyan, Ph.D., Title: Manager 06/08/2023 Signature of Reporting Person Date Flagship V VentureLabs Rx Fund, L.P., By: Flagship Ventures Fund V General Partner LLC, its General Partner, By: /s/ Noubar B. Afeyan, Ph.D., Title: Manager 06/08/2023 Signature of Reporting Person Date /s/ Noubar B. Afeyan, Ph.D. 06/08/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.30 to $6.415, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. ( 2 )Represents shares held directly by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any. ( 3 )Represents shares held directly by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx"). Flagship V GP is the general partner of Flagship Fund V Rx. Each of the reporting persons except Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any. ( 4 )The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.20 to $6.36, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. ( 5 )Represents shares held directly by Flagship VentureLabs V LLC. ("VentureLabs V"). VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. Dr. Afeyan is the CEO and sole stockholder of Flagship Pioneering. Each of the reporting persons except VentureLabs V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any. ( 6 )Represents shares held directly by Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI"). Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP") is the general partner of Flagship Fund VI. Flagship Pioneering is the manager of Flagship Fund VI GP. Each of the reporting persons except Flagship Fund VI disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

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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