Sec Form 4 Filing - MPM BioVentures 2014, L.P. @ Werewolf Therapeutics, Inc. - 2025-11-26

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 MPM BioVentures 2014, L.P. 2. Issuer Name and Ticker or Trading Symbol Werewolf Therapeutics, Inc. [ HOWL] 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 MPM BIOIMPACT LLC, 399 BOYLSTON STREET, SUITE 1100 3. Date of Earliest Transaction (MM/DD/YY) 11/26/2025 (Street) BOSTON, MA02116 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 11/26/2025 S( 1 ) 60,733 ( 2 ) D $ 0.98 ( 3 ) 5,065,037 I See Footnotes ( 4 ) ( 5 ) Common Stock 11/28/2025 S( 1 ) 20,277 ( 6 ) D $ 0.99 ( 7 ) 5,044,760 I See Footnotes ( 4 ) ( 8 ) Common Stock 12/01/2025 S( 1 ) 60,917 ( 9 ) D $ 0.94 ( 10 ) 4,983,843 I See Footnotes ( 4 ) ( 11 )

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 MPM BioVentures 2014, L.P. C/O MPM BIOIMPACT LLC 399 BOYLSTON STREET, SUITE 1100 BOSTON, MA02116 X MPM BioVentures 2014 (B), L.P. C/O MPM BIOIMPACT 399 BOYLSTON STREET, SUITE 1100 BOSTON, MA02116 X MPM BioVentures 2014 LLC C/O MPM BIOIMPACT LLC 399 BOYLSTON STREET, SUITE 1100 BOSTON, MA02116 X MPM BioVentures 2014 GP LLC C/O MPM BIOIMPACT LLC 399 BOYLSTON STREET, SUITE 1100 BOSTON, MA02116 X MPM Asset Management Investors BV2014 LLC C/O MPM BIOIMPACT LLC 399 BOYLSTON STREET, SUITE 1100 BOSTON, MA02116 X Signatures /s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the manager of MPM Asset Management Investors BV2014 LLC 12/01/2025 Signature of Reporting Person Date /s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC, the GP of MPM BioVentures 2014, L.P. 12/01/2025 Signature of Reporting Person Date /s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC 12/01/2025 Signature of Reporting Person Date /s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC 12/01/2025 Signature of Reporting Person Date /s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC, the GP of MPM BioVentures 2014 (B), L.P. 12/01/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 dated September 24, 2025. ( 2 )The shares were sold as follows: 4,170 by MPM Asset Management LLC ("AM LLC"), 26,343 by MPM BioVentures 2014, L.P. ("BV 2014"), 1,757 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)"), 907 by MPM Asset Management Investors BV2014 LLC ("AM BV2014"), 5,801 by MPM Oncology Innovations Fund, L.P. ("MPM OIF") and 21,755 by UBS Oncology Impact Fund L.P. ("UBS Oncology"). ( 3 )The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.9328 to $1.01 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. ( 4 )MPM BioVentures 2014 GP LLC and MPM BioVentures 2014 LLC ("BV LLC") are the direct and indirect general partners of BV 2014 and BV 2014(B). BV LLC is the manager of AM BV2014. MPM Oncology Innovations Fund GP LLC ("MPM OIF GP") is the general partner of MPM OIF. MPM BioImpact LLC ("BioImpact") is the General Partner of Oncology Impact Fund (Cayman) Management L.P., the General Partner of UBS Oncology. Ansbert Gadicke is a member of AM LLC, a managing director of BV LLC, a manager of MPM OIF GP and the managing partner of BioImpact. Each Reporting Person disclaims beneficial ownership of the securities except to the extent of his or its pecuniary interest therein. ( 5 )The shares are held as follows: 347,875 by AM LLC, 2,196,856 by BV 2014, 146,527 by BV 2014(B), 75,615 by AM BV2014, 481,700 by MPM OIF and 1,816,464 by UBS Oncology ( 6 )The shares were sold as follows: 1,392 by AM LLC, 8,795 by BV 2014, 587 by BV 2014(B), 303 by AM BV2014, 1,937 by MPM OIF and 7,263 by UBS Oncology. ( 7 )The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.9681 to $1.01 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. ( 8 )The shares are held as follows: 346,483 by AM LLC, 2,188,061 by BV 2014, 145,940 by BV 2014(B), 75,312 by AM BV2014, 479,763 by MPM OIF and 1,809,201 by UBS Oncology ( 9 )The shares were sold as follows: 4,182 by AM LLC, 26,423 by BV 2014, 1,762 by BV 2014(B), 910 by AM BV2014, 5,819 by MPM OIF and 21,821 by UBS Oncology. ( 10 )The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.905 to $1.00 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. ( 11 )The shares are held as follows: 342,301 by AM LLC, 2,161,638 by BV 2014, 144,178 by BV 2014(B), 74,402 by AM BV2014, 473,944 by MPM OIF and 1,787,380 by UBS Oncology.

Remarks: This filing is 1 of 2 identical filings due to limitations on number of Reporting Persons. See Form 4 filed by Ansbert Gadicke.

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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