Sec Form 4 Filing - Kayyem Jon Faiz @ Inhibrx Biosciences, Inc. - 2024-05-29

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 Kayyem Jon Faiz 2. Issuer Name and Ticker or Trading Symbol Inhibrx Biosciences, Inc. [ INXB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O INHIBRX BIOSCIENCES, INC., 11025 NORTH TORREY PINES ROAD, SUITE 140 3. Date of Earliest Transaction (MM/DD/YY) 05/29/2024 (Street) LA JOLLA, CA92037 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ 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 05/29/2024 A 806,075 A 806,075 I By The Jon F. Kayyem and Paige Gates-Kayyem Family Trust ( 2 ) Common Stock 05/29/2024 A 6,250 A 6,250 I By Child A ( 3 ) Common Stock 05/29/2024 A 6,250 A 6,250 I By Child B ( 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 Stock Option (right to buy) $ 15.86 05/30/2024( 5 ) A 30,000 ( 6 ) 05/30/2034 Common Stock 30,000 $ 0 30,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Kayyem Jon Faiz C/O INHIBRX BIOSCIENCES, INC. 11025 NORTH TORREY PINES ROAD, SUITE 140 LA JOLLA, CA92037 X Signatures /s/ Kelly D. Deck, Chief Financial Officer of Inhibrx Biosciences, Inc., as attorney-in-fact 05/30/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The transactions reported herein are the result of the consummation on May 29, 2024 of the distribution by Inhibrx, Inc. of 92% of the issued and outstanding shares of common stock of its subsidiary, Inhibrx Biosciences, Inc. (the "Issuer"), to holders of shares of Inhibrx, Inc.'s common stock as of the distribution record date of May 17, 2024, on a pro rata basis, at a ratio of one share of the Company's common stock for every four shares of Inhibrx, Inc.'s issued and outstanding common stock held on the distribution record date. These transactions are voluntarily reported notwithstanding the exemption provided by Rule 16a-9. ( 2 )These securities are directly owned by The Jon F. Kayyem and Paige Gates-Kayyem Family Trust. Jon Faiz Kayyem is the trustee of The Jon F. Kayyem and Paige Gates-Kayyem Family Trust and he disclaims beneficial ownership of these securities, except to the extent of any indirect pecuniary interest in his distributive shares therein. ( 3 )These securities are held in a custodial account managed by the reporting person for the benefit of the reporting person's minor child, Child A. The reporting person disclaims beneficial ownership of these securities, except to the extent of any indirect pecuniary interest in his distributive shares therein. ( 4 )These securities are held in a custodial account managed by the reporting person for the benefit of the reporting person's minor child, Child B. The reporting person disclaims beneficial ownership of these securities, except to the extent of any indirect pecuniary interest in his distributive shares therein. ( 5 )This stock option was granted following the consummation of the merger of Inhibrx, Inc. with a wholly owned indirect subsidiary of Sanofi. ( 6 )This stock option will be fully exercisable on May 30, 2025, subject to the reporting person?s continued service through such 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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