INBX Inhibrx Biosciences Inc

As filed with the Securities and Exchange Commission on May 30, 2024

Registration No. 333-259313

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

POST-EFFECTIVE AMENDMENT NO. 1 TO:

FORM S-3 REGISTRATION STATEMENT NO. 333-259313

UNDER

THE SECURITIES ACT OF 1933

Inhibrx, Inc.

(Exact name of registrant as specified in its charter)

Michael J. Tolpa

President

Inhibrx, Inc.

251 Little Falls Drive

Wilmington, Delaware 19808

(302) 636-5401

(Name, address and telephone number of agent for service)

Copies to:

Michael J. Aiello, Esq.

Amanda Fenster, Esq.

Weil, Gotshal & Manges LLP

767 Fifth Avenue

New York, New York 10153

(212) 310-8000

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

EXPLANATORY NOTE

DEREGISTRATION OF SHARES

Inhibrx, Inc., a Delaware corporation (the “Registrant”), is filing with the U.S. Securities and Exchange Commission this post-effective amendment (the “Post-Effective Amendment”) to withdraw and remove from registration any and all unsold securities of the Registrant, previously registered under the Registration Statement on Form S-3 (File No. 333-259313) (the “Registration Statement”), which was filed with the Securities and Exchange Commission on September 3, 2021.

On May 30, 2024, pursuant to the terms of the Agreement and Plan of Merger, dated as of January 22, 2024, by and among the Registrant, Aventis Inc., a Pennsylvania corporation (“Aventis”), and Art Acquisition Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Aventis (“Merger Sub”), Merger Sub merged with and into the Registrant with the Registrant surviving the merger as a wholly owned subsidiary of Aventis (the “Merger”).

As a result of the Merger, the Registrant has terminated all offerings and sales pursuant to the Registration Statement. In accordance with an undertaking made by the Registrant in the Registration Statement to remove from registration, by means of a post-effective amendment, any of the securities registered under the Registration Statement that remain unsold at the termination of the offering, the Registrant hereby terminates the effectiveness of the Registration Statement and removes and withdraws from registration any and all securities of the Registrant registered but remaining unissued and/or unsold under the Registration Statement as of the date hereof.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused the Post-Effective Amendment to the Registration Statement described above to be signed on its behalf by the undersigned, thereunto duly authorized, in Bridgewater Township, State of New Jersey, on May 30, 2024.

Pursuant to Rule 478 of the Securities Act of 1933, as amended, no other person is required to sign this Post-Effective Amendment to the Registration Statement.