Sec Form 3 Filing - 5AM VENTURES III, L.P. @ ARVINAS HOLDING COMPANY, LLC - 2018-09-26

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 5AM VENTURES III, L.P. 2. Issuer Name and Ticker or Trading Symbol ARVINAS HOLDING COMPANY, LLC [ ARVN] 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) 501 2ND STREET, SUITE 350 3. Date of Earliest Transaction (MM/DD/YY) 09/26/2018 (Street) SAN FRANCISCO, CA94107 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

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 Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 2,862,649 I See Footnote ( 2 ) ( 4 ) Series A Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 73,777 I See Footnote ( 3 ) ( 4 ) Series B Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 1,338,679 I See Footnote ( 2 ) ( 4 ) Series B Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 34,500 I See Footnote ( 3 ) ( 4 ) Series C Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 662,864 I See Footnote ( 2 ) ( 4 ) Series C Preferred Stock ( 1 ) ( 1 ) ( 1 ) Common Stock 17,083 I See Footnote ( 3 ) ( 4 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other 5AM VENTURES III, L.P. 501 2ND STREET, SUITE 350 SAN FRANCISCO, CA94107 X 5AM Co-Investors III, L.P. 501 2ND STREET, SUITE 350 SAN FRANCISCO, CA94107 X 5AM Partners III, LLC 501 2ND STREET, SUITE 350 SAN FRANCISCO, CA94107 X ROCKLAGE SCOTT M 501 2ND STREET, SUITE 350 SAN FRANCISCO, CA94107 X DIEKMAN JOHN D 501 2ND STREET, SUITE 350 SAN FRANCISCO, CA94107 X Schwab Andrew J. 501 2ND STREET, SUITE 350 SAN FRANCISCO, CA94107 X Signatures 5AM VENTURES III, L.P. By: 5AM Partners III, LLC, its General Partner /s/ Andrew J. Schwab 09/26/2018 Signature of Reporting Person Date 5AM CO-INVESTORS III, L.P. By: 5AM Partners III, LLC, its General Partner /s/ Andrew J. Schwab 09/26/2018 Signature of Reporting Person Date 5AM PARTNERS III, LLC /s/ Andrew J. Schwab 09/26/2018 Signature of Reporting Person Date /s/ Scott M. Rocklage 09/26/2018 Signature of Reporting Person Date /s/ John D. Diekman 09/26/2018 Signature of Reporting Person Date /s/ Andrew J. Schwab 09/26/2018 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Series A Preferred Stock, the Series B Preferred Stock and the Series C Preferred Stock is convertible into Common Stock on a 3.25-for-one basis into the number of shares of Common Stock shown in Column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering without payment of further consideration. The shares have no expiration date. ( 2 )9,303,611 shares of Series A Preferred Stock, 4,350,709 shares of Series B Preferred Stock and 2,154,311 shares of Series C Preferred Stock are held by 5AM Ventures III, L.P. ("Ventures III"). ( 3 )239,776 shares of Series A Preferred Stock, 112,128 shares of Series B Preferred Stock and 55,522 shares of Series C Preferred Stock are held by 5AM Co-Investors III, L.P. ("Co-Investors III"). ( 4 )5AM Partners III, LLC ("Partners III") is the sole general partner of Ventures III and Co-Investors III. Dr. John D. Diekman, Andrew J. Schwab and Dr. Scott M. Rocklage, are the managing members of Partners III, and may be deemed to have shared voting and investment power over the shares beneficially owned by Ventures III and Co-Investors III. Each of Partners III, Dr. Diekman, Mr. Schwab and Dr. Rocklage disclaim beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

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).

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