Sec Form 3 Filing - Medicxi Ventures Management (Jersey) Ltd @ Phathom Pharmaceuticals, Inc. - 2024-01-24

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 Medicxi Ventures Management (Jersey) Ltd 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 INTERTRUST FUND SERVICES (JERSEY), LIMITED 44 ESPLANADE 3. Date of Earliest Transaction (MM/DD/YY) 01/24/2024 (Street) ST. HELIER, Y9JE4 9WG 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 3,673,602 I By Medicxi Growth I LP ( 1 ) Common Stock 87,267 I By Medicxi Growth Co-Invest I LP ( 2 ) Common Stock 3,641,728 I By Medicxi IV LP ( 3 ) Common Stock 61,975 I By Medicxi Co-Invest IV LP ( 4 )

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 Medicxi Ventures Management (Jersey) Ltd C/O INTERTRUST FUND SERVICES (JERSEY) LIMITED 44 ESPLANADE ST. HELIER, Y9JE4 9WG X Medicxi Growth I GP Ltd C/O INTERTRUST FUND SERVICES (JERSEY) LIMITED 44 ESPLANADE ST. HELIER, Y9JE4 9WG X Medicxi Growth I LP C/O INTERTRUST FUND SERVICES (JERSEY) LIMITED 44 ESPLANADE ST. HELIER, Y9JE4 9WG X Medicxi Growth Co-Invest I LP C/O INTERTRUST FUND SERVICES (JERSEY) LIMITED 44 ESPLANADE ST. HELIER, Y9JE4 9WG X Medicxi IV GP Ltd C/O INTERTRUST FUND SERVICES (JERSEY) LIMITED 44 ESPLANADE ST. HELIER, Y9JE4 9WG X Medicxi IV LP C/O INTERTRUST FUND SERVICES (JERSEY) LIMITED 44 ESPLANADE ST. HELIER, Y9JE4 9WG X Medicxi Co-Invest IV LP C/O INTERTRUST FUND SERVICES (JERSEY) LIMITED 44 ESPLANADE ST. HELIER, Y9JE4 9WG X Signatures MEDICXI VENTURES MANAGEMENT (JERSEY) LIMITED, By: /s/ Giles Johnstone-Scott, Director 01/26/2024 Signature of Reporting Person Date MEDICXI GROWTH I LP, By: Medicxi Ventures Management (Jersey) Limited, By: /s/ Giles Johnstone-Scott, Director 01/26/2024 Signature of Reporting Person Date MEDICXI GROWTH CO-INVEST I LP, By: Medicxi Ventures Management (Jersey) Limited, By: /s/ Giles Johnstone-Scott, Director 01/26/2024 Signature of Reporting Person Date MEDICXI GROWTH I GP LIMITED, By: /s/ Nigel Crocker, Alternate Director 01/26/2024 Signature of Reporting Person Date MEDICXI IV LP, By: Medicxi Ventures Management (Jersey) Limited, By: /s/ Giles Johnstone-Scott, Director 01/26/2024 Signature of Reporting Person Date MEDICXI CO-INVEST IV LP, By: Medicxi Ventures Management (Jersey) Limited, By: /s/ Giles Johnstone-Scott, Director 01/26/2024 Signature of Reporting Person Date MEDICXI IV GP LIMITED, By: /s/ Nigel Crocker, Alternate Director 01/26/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Shares held by Medicxi Growth I LP ("Growth I"). Medicxi Growth I GP Limited ("Growth I GP") is the sole general partner of Growth I, and Medicxi Ventures Management (Jersey) Limited ("Medicxi Manager") is the sole manager of Growth I. The Reporting Persons disclaim Section 16 beneficial ownership of the securities held by Growth I, except to the extent of their respective pecuniary interest therein, if any, and this report shall not be deemed to be an admission that they are the beneficial owners of such shares for Section 16 or any other purpose. ( 2 )Shares held by Medicxi Growth Co-Invest I LP ("Growth Co-Invest I"). Growth I GP is the sole general partner of Growth Co-Invest I, and Medicxi Manager is the sole manager of Growth Co-Invest I. The Reporting Persons disclaim Section 16 beneficial ownership of the securities held by Growth Co-Invest I, except to the extent of their respective pecuniary interest therein, if any, and this report shall not be deemed to be an admission that they are the beneficial owners of such shares for Section 16 or any other purpose. ( 3 )Shares held Medicxi IV LP ("Medicxi IV"). Medicxi IV GP Limited ("Medicxi IV GP") is the sole general partner of Medicxi IV, and Medicxi Manager is the sole manager of Medicxi IV. The Reporting Persons disclaim Section 16 beneficial ownership of the securities held by Medicxi IV, except to the extent of their respective pecuniary interest therein, if any, and this report shall not be deemed to be an admission that they are the beneficial owners of such shares for Section 16 or any other purpose. ( 4 )Shares held by Medicxi Co-Invest IV LP ("Co-Invest IV"). Medicxi IV GP is the sole general partner of Co-Invest IV, and Medicxi Manager is the sole manager of Co-Invest IV. The Reporting Persons disclaim Section 16 beneficial ownership of the securities held by Co-Invest IV, except to the extent of their respective pecuniary interest therein, if any, and this report shall not be deemed to be an admission that they are the beneficial owners of such shares for Section 16 or any other purpose.

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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