Sec Form 3 Filing - TAKEDA PHARMACEUTICAL CO LTD @ HilleVax, Inc. - 2022-04-28

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 TAKEDA PHARMACEUTICAL CO LTD 2. Issuer Name and Ticker or Trading Symbol HilleVax, Inc. [ HLVX] 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) 1-1, NIHONBASHI-HONCHO 2-CHOME 3. Date of Earliest Transaction (MM/DD/YY) 04/28/2022 (Street) CHUO-KU, TOKYO, M0103-8668 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 500,000 I See Explanation of Responses( 1 )

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 Warrant (Right to Buy) $ 0.0001 04/28/2022 04/28/2032 Common Stock 3,500,000 I See Explanation of Responses( 1 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other TAKEDA PHARMACEUTICAL CO LTD 1-1, NIHONBASHI-HONCHO 2-CHOME CHUO-KU, TOKYO, M0103-8668 X Takeda Vaccines, Inc. 75 SIDNEY STREET CAMBRIDGE, MA02139 X Signatures /s/ Yoshihiro Nakagawa, Global General Counsel of Takeda Pharmaceutical Company Limited 04/29/2022 Signature of Reporting Person Date /s/ Michael Martin, Authorized Signatory, Takeda Vaccines, Inc. 04/29/2022 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Takeda Pharmaceutical Company Ltd's beneficial ownership of the reported securities is comprised of 500,000 shares of Common Stock and a Warrant to purchase 3,500,000 shares of Common Stock; each held by Takeda Vaccines, Inc., an indirect wholly-owned subsidiary of Takeda Pharmaceutical Company Limited. Takeda Vaccines, Inc. is owned directly by Takeda Pharmaceuticals U.S.A., Inc., which is owned directly by both Takeda Pharmaceutical Company Limited (72.70%) and Takeda Pharmaceuticals International AG (27.30%). Takeda Pharmaceuticals International AG is a wholly-owned direct subsidiary of Takeda Pharmaceutical Company Limited.

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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