Sec Form 4 Filing - Frazier Life Sciences IX, L.P. @ Phathom Pharmaceuticals, Inc. - 2020-06-12

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 Frazier Life Sciences IX, L.P. 2. Issuer Name and Ticker or Trading Symbol Phathom Pharmaceuticals, Inc. [ PHAT] 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) C/O FRAZIER HEALTHCARE PARTNERS, 601 UNION STREET, SUITE 3200 3. Date of Earliest Transaction (MM/DD/YY) 06/12/2020 (Street) SEATTLE, WA98101 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 06/12/2020 J( 1 ) 1,456,854 D $ 0 5,827,415 D ( 2 ) Common Stock 1 ( 3 ) I See footnote ( 4 ) Common Stock 12,596 ( 3 ) I See footnote ( 5 ) Common Stock 3,912 ( 3 ) I See footnote ( 6 ) Common Stock 14,937 ( 3 ) I See footnote ( 7 )

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 Expirat ion 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 Frazier Life Sciences IX, L.P. C/O FRAZIER HEALTHCARE PARTNERS 601 UNION STREET, SUITE 3200 SEATTLE, WA98101 X FHMLS IX, L.P. C/O FRAZIER HEALTHCARE PARTNERS 601 UNION STREET, SUITE 3200 SEATTLE, WA98101 X FHMLS IX, L.L.C. C/O FRAZIER HEALTHCARE PARTNERS 601 UNION STREET, SUITE 3200 SEATTLE, WA98101 X Topper James N C/O FRAZIER HEALTHCARE PARTNERS 601 UNION STREET, SUITE 3200 SEATTLE, WA98101 X X Heron Patrick J C/O FRAZIER HEALTHCARE PARTNERS 601 UNION STREET, SUITE 3200 SEATTLE, WA98101 X Signatures Frazier Life Sciences IX, L.P., By: FHMLS IX, L.P., its general partner, By: FHMLS IX, L.L.C., its general, partner, By: /s/ Steve R. Bailey, Chief Financial Officer 06/16/2020 Signature of Reporting Person Date FHMLS IX, L.P., By: FHMLS IX, L.L.C., its general partner, By: /s/ Steve R. Bailey, Chief Financial Officer 06/16/2020 Signature of Reporting Person Date FHMLS IX, L.L.C., By: /s/ Steve R. Bailey, Chief Financial Officer 06/16/2020 Signature of Reporting Person Date /s/ Steve R. Bailey, Attorney-in-Fact for James Topper 06/16/2020 Signature of Reporting Person Date /s/ Steve R. Bailey, Attorney-in-Fact for Patrick Heron 06/16/2020 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents a pro rata distribution in-kind by Frazier Life Sciences IX, L.P. ("FLS IX") to its limited partners for no consideration. ( 2 )Represents shares held of record by FLS IX. The general partner of FLS IX is FHMLS IX, L.P., and the general partner of FHMLS IX, L.P. is FHMLS IX, L.L.C. James Topper and Patrick Heron are the sole managing members of FHMLS IX, L.L.C. and share voting and investment power of the securities held by FLS IX. Dr. Topper and Mr. Heron disclaim beneficial ownership of such securities except to the extent of their pecuniary interest therein. ( 3 )Reflects shares of Common Stock received in the distribution in-kind described herein. ( 4 )Represents shares held of record by FHMLS IX, L.L.C. James Topper and Patrick Heron are the sole managing members of FHMLS IX, L.L.C. and share voting and investment power of the securities held by FLS IX. Dr. Topper and Mr. Heron disclaim beneficial ownership of such securities except to the extent of their pecuniary interest therein. These shares were previously held through FLS IX. ( 5 )Represents shares held directly by Dr. Topper. These shares were previously held through FLS IX. ( 6 )Represents shares held of record by Topper Group III LLC. Dr. Topper is a manager of Topper Group III LLC and has voting and investment power of the securities held by Topper Group III LLC. These shares were previously held through FLS IX. ( 7 )Represents shares held by The Heron Living Trust 11/30/2004. Mr. Heron is the co-trustee of The Heron Living Trust 11/30/2004 and has voting and investment power of the securities held by The Heron Living Trust 11/30/2004. These shares were previously held through FLS IX.

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