Sec Form 3 Filing - Polaris Venture Partners V, L.P. @ Adagio Therapeutics, Inc. - 2022-03-28

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

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Polaris Venture Partners V, L.P. 2. Issuer Name and Ticker or Trading Symbol Adagio Therapeutics, Inc. [ ADGI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) X __ Other (specify below) See Remarks (Last) (First) (Middle) ONE MARINA PARK DRIVE, 10TH, FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 03/28/2022 (Street) BOSTON, MA02210 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 3,120,194 I See Footnote( 1 ) Common Stock 60,814 I See Footnote( 2 ) Common Stock 21,374 I See Footnote( 3 ) Common Stock 31,198 I See Footnote( 4 ) Common Stock 4,800,460 I See Footnote( 5 )( 6 ) Common Stock 497,660 I See Footnote( 7 )( 8 )

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 Polaris Venture Partners V, L.P. ONE MARINA PARK DRIVE, 10TH FLOOR BOSTON, MA02210 See Remarks Polaris Venture Partners Entrepreneurs' Fund V, L.P. C/O POLARIS PARTNERS ONE MARINA PARK DRIVE, 10TH FL. BOSTON, MA02210 See Remarks Polaris Venture Partners Founders' Fund V, L.P. ONE MARINA PARK DRIVE 10TH FLOOR BOSTON, MA02210 See Remarks Polaris Venture Partners Special Founders' Fund V, L.P. ONE MARINA PARK DRIVE 10TH FLOOR BOSTON, MA02110 See Remarks Polaris Venture Management Co. V, L.L.C. ONE MARINA PARK DRIVE 10TH FLOOR BOSTON, MA02210 See Remarks Polaris Partners IX, L.P. ONE MARINA PARK DRIVE 10TH FLOOR BOSTON, MA02210 See Remarks Polaris Partners GP IX, L.L.C. ONE MARINA PARK DRIVE 10TH FLOOR BOSTON, MA02210 See Remarks Polaris Healthcare Technology Opportunities Fund, L.P. ONE MARINA PARK DRIVE 10TH FLOOR BOSTON, MA02210 See Remarks Polaris Healthcare Technology Opportunities Fund GP, L.L.C. ONE MARINA PARK DRIVE 10TH FLOOR BOSTON, MA02210 See Remarks Flint Jonathan A ONE MARINA PARK DRIVE 10TH FLOOR BOSTON, MA02210 See Remarks Signatures /s/ Lauren Crockett, as attorney in fact for Polaris Venture Management Co. V, L.L.C., general partner of Polaris Venture Partners V, L.P. 03/30/2022 Signature of Reporting Person Date /s/ Lauren Crockett, as attorney in fact for Polaris Venture Management Co. V, L.L.C., general partner of Polaris Venture Partners Entrepreneurs' Fund V, L.P. 03/30/2022 Signature of Reporting Person Date /s/ Lauren Crockett, as attorney in fact for Polaris Venture Management Co. V, L.L.C., general partner of Polaris Venture Partners Founders' Fund V, L.P. 03/30/2022 Signature of Reporting Person Date /s/ Lauren Crockett, as attorney in fact for Polaris Venture Management Co. V, L.L.C., general partner of Polaris Venture Partners Special Founders' Fund V, L.P. 03/30/2022 Signature of Reporting Person Date /s/ Lauren Crockett, as attorney in fact for Polaris Venture Management Co. V, L.L.C. 03/30/2022 Signature of Reporting Person Date /s/ Lauren Crockett, general counsel for Polaris Partners GP IX, L.L.C., general partner of Polaris Partners IX, L.P. 03/30/2022 Signature of Reporting Person Date /s/ Lauren Crockett, as general counsel for Polaris Partners GP IX, L.L.C. 03/30/2022 Signature of Reporting Person Date /s/ Lauren Crockett, as general counsel for Polaris Healthcare Technology Opportunities Fund GP, L.L.C., general partner of Polaris Healthcare Technology Opportunities Fund, L.P. 03/30/2022 Signature of Reporting Person Date /s/ Lauren Crockett, as general counsel for Polaris Healthcare Technology Opportunities Fund GP, L.L.C. 03/30/2022 Signature of Reporting Person Date /s/ Lauren Crockett, Attorney-in-Fact Jonathan Flint 03/30/2022 Signature of Reporting Person Date

Explanation of Responses:

( 1 )These shares are held of record by Polaris Venture Partners V, L.P. ("PVP V"). The general partner of PVP V is Polaris Venture Management Co. V, L.L.C. ("PVM V") and may be deemed to have shared voting and investment power with respect to the shares held by PVP V. Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of PVM V and may be deemed to have shared voting and dispositive power over the shares held by PVP V. Each of PVM V, Flint and McGuire disclaims beneficial ownership of the securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, excep t to the extent of their respective pecuniary interests therein. McGuire is a director of the Issuer and, accordingly, files separate Section 16 reports. ( 2 )These shares are held of record by Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("PVPEF V"). The general partner of PVPEF V is PVM V and may be deemed to have shared voting and investment power with respect to the shares held by PVPEF V. Flint and McGuire are the managing members of PVM V and may be deemed to have shared voting and dispositive power over the shares held by PVPEF V. Each of PVM V, Flint and McGuire disclaims beneficial ownership of the securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. McGuire is a director of the Issuer and, accordingly, files separate Section 16 reports. ( 3 )These shares are held of record by Polaris Venture Partners Founders' Fund V, L.P. ("PVPFF V"). The general partner of PVPFF V is PVM V and may be deemed to have shared voting and investment power with respect to the shares held by PVPFF V. Flint and McGuire are the managing members of PVM V and may be deemed to have shared voting and dispositive power over the shares held by PVPEF V. Each of PVM V, Flint and McGuire disclaims beneficial ownership of the securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. McGuire is a director of the Issuer and, accordingly, files separate Section 16 reports. ( 4 )These shares are held of record by Polaris Venture Partners Special Founders' Fund V, L.P. ("PVPSFF V"). The general partner of PVPSFF V is PVM V and may be deemed to have shared voting and investment power with respect to the shares held by PVPSFF V. Flint and McGuire are the managing members of PVM V and may be deemed to have shared voting and dispositive power over the shares held by PVPEF V. Each of PVM V, Flint and McGuire disclaims beneficial ownership of the securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. McGuire is a director of the Issuer and, accordingly, files separate Section 16 reports. ( 5 )These shares are held of record by Polaris Partners IX, L.P. ("PP IX"). The general partner of PP IX is Polaris Partners GP IX, L.L.C. ("PPGP IX") and may be deemed to have shared voting and investment power with respect to the shares held by PP IX. Each of David Barrett ("Barrett"), Brian Chee ("Chee"), Amir Nashat ("Nashat") and Amy Schulman ("Schulman") are the managing members of PPGP IX (collectively, the "PPGP IX Managing Members"), and McGuire is an interest holder in PPGP IX, and may be deemed to have shared voting and dispositive power over the shares held by PP IX. Each of PPGP IX, the PPGP IX Managing Members and McGuire disclaims beneficial ownership of the securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. ( 6 )(Continued from footnote 5) McGuire is a director of the Issuer and, accordingly, files separate Section 16 reports. ( 7 )These shares are held of record by Polaris Healthcare Technology Opportunities Fund, L.P. ("PHCT"). The general partner of PHCT is Polaris Healthcare Technology Opportunities Fund GP, L.L.C. ("PHCT GP") and may be deemed to have shared voting and investment power with respect to the shares held by PHCT. Each of Barrett, Chee, Nashat and Schulman are the managing members of PHCT GP (collectively, the "PHCT GP Managing Members"), and McGuire is an interest holder in PHCT GP, and may be deemed to have shared voting and dispositive power over the shares held by PHCT. Each of PHCT GP, the PHCT GP Managing Members and McGuire disclaims beneficial ownership of the securities and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. ( 8 )(Continued from footnote 7) McGuire is a director of the Issuer and, accordingly, files separate Section 16 reports.

Remarks: This form 3 is not being filed in connection with the acquisition or deposition of any securities of the issuer. As disclosed by (among others) the Reporting Persons on an amendment to a Report on Schedule 13D filed in respect of the Issuer on the date hereof, on March 28, 2022, Mithril II LP ("Mithril"), and (i) M28 Capital Management LP (together with certain of its affiliates, "M28"), (ii) PVP V, PVPEF V, PVPFF V, PVPSFF V, PP IX, and PHCT (each as defined below, and collectively, "Polaris"), (iii) Adimab, LLC and (iv) Population Health Equity Partners III, L.P., Population Health Equity Partners VII, L.P. and Clive Meanwell ("Population Health"), orally agreed to coordinate and cooperate in certain of their activities with regard to the Issuer, which agreement was subsequently memorialized, also on March 28, 2022, in an email circulated among representatives of such persons. That agreement provides that each such person will vote its shares of Common Stock in favor of the election of certain director nominees at the Issuer's 2022 annual meeting. By virtue of such agreement, the forgoing persons may be deemed to be part of a "group" (within the meaning of Section 13(d)(3) of the Exchange Act) comprised of such persons. The Reporting Persons expressly disclaim beneficial ownership over any Common Stock that they may be deemed to beneficially own solely by reason of the agreement reached among Mithril, M28, Polaris, Adimab, LLC and Population Health, and beneficial ownership of any securities of the Issuer other than those reported on this Form 3.

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).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.