FORM 4 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
or Section 30(h) of the Investment Company Act of 1940
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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
1. Name and Address of Reporting Person *
Sanofi

(Last) (First) (Middle)
46 AVENUE DE LA GRANDE ARMEE

(Street)
PARIS 75017

(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
Latigo Biotherapeutics, Inc. [ LTGO ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director X 10% Owner
Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
08/10/2026
4. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 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 08/10/2026   C   494,800 A (1) 494,800 I (3) See footnote (3)
Common Stock 08/10/2026   C   177,978 A (2) 672,788 I (3) See footnote (3)
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 (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 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 (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (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: 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 B Preferred Stock (1) 08/10/2026   C     494,800   (1)   (1) Common Stock 494,800 (1) 0 I (3) See footnote (3)
Convertible Promissory Note (2) 08/10/2026   C     177,978   (2)   (2) Common Stock 177,978 (2) 0 I (3) See footnote (3)
Explanation of Responses:
1. The Series B Convertible Preferred Stock (the "Preferred Stock") converted automatically into shares of common stock on a one-for-one basis upon the closing of the Issuer's initial public offering on August 10, 2026 (the "IPO") without payment of consideration.
2. The principal amount of the convertible promissory note (the "Note"), together with any accrued but unpaid interest, automatically converted into shares of common stock upon the closing of the IPO at a conversion price equal to the IPO price of the common stock.
3. Sanofi beneficially owns the securities reported herein through various wholly-owned subsidiaries.
Remarks:
Immediately upon consummation of the IPO, Sanofi's beneficial ownership of the common stock fell below 10%, as a result of the issuance of additional shares of common stock. The convertibility and expiration of the Preferred Stock and Note prior to the IPO are described in Sanofi's Form 3, filed with the Securities and Exchange Commission on August 12, 2026.
/s/ Alexandra Roger, as attorney-in-fact for Sanofi 08/12/2026
** Signature of Reporting Person Date
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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