ABIVAX Société Anonyme美股招股说明书(2026-06-30版)

$600,000,000American Depositary SharesRepresenting Ordinary Shares We are offeringof our American Depositary Shares (“ADSs”), each representing one ordinary share, €0.01 nominalvalue per share, in a public offering. Our ordinary shares are listed on the regulated market of Euronext in Paris (“Euronext Paris”) under the symbol “ABVX.”Our ADSs are listed on The Nasdaq Global Market (“Nasdaq”) under the symbol “ABVX.” On June29, 2026, the last reportedsale price of our ordinary shares on Euronext Paris was €83.30 per ordinary share and the last reported sale price of our ADSs onNasdaq was $96.15 per ADS. Investing in our securities involves a high degree of risk. Before deciding whether to invest in oursecurities, you should consider carefully the risks that we have described beginning on page S-9 ofthis prospectus supplement under the caption “Risk Factors” and under the caption “RiskFactors”on page6 of the accompanying prospectus and in our most recent Annual Report on Form 20-F andany other reports or documents incorporated by reference into this prospectus supplement and theaccompanying prospectus. Neither the Securities and Exchange Commission nor any U.S. state or other securities commission has approved ordisapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthfulor complete. Any representation to the contrary is a criminal offense. PerADSTotalPublic offering price$$Underwriting discounts and commissions(1)$$Proceeds to us (before expenses)$$ (1)We refer you to “Underwriting” beginning on page S-29 of this prospectus supplement for additional information regardingunderwriting compensation. Delivery of the ADSs is expected to be made on or about, 2026 (the “initial settlement date”), through the book-entry facilities of The Depository Trust Company. We have granted an option to the underwriters, exercisable on or before theinitial settlement date, to purchase up to an aggregate ofadditional ADSs at the public offering price. Table of Contents TABLE OF CONTENTS Prospectus Supplement ABOUT THIS PROSPECTUS SUPPLEMENTSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSPROSPECTUS SUMMARYRISK FACTORSUSE OF PROCEEDSCAPITALIZATIONDILUTIONTAXATIONUNDERWRITINGMATERIAL CHANGESENFORCEMENT OF CIVIL LIABILITIESLEGAL MATTERSEXPERTSWHERE YOU CAN FIND ADDITIONAL INFORMATIONINCORPORATION OF CERTAIN INFORMATION BY REFERENCE Prospectus ABOUT THIS PROSPECTUSPROSPECTUS SUMMARYRISK FACTORSSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSUSE OF PROCEEDS SELLING SECURITY HOLDERS DESCRIPTION OF SHARE CAPITAL LIMITATIONS AFFECTING SHAREHOLDERS OF A FRENCH COMPANY DESCRIPTION OF DEBT SECURITIES LEGAL MATTERS EXPERTS ENFORCEMENT OF CIVIL LIABILITIES WHERE YOU CAN FIND MORE INFORMATION INCORPORATION OF DOCUMENTS BY REFERENCE EXPENSES ASSOCIATED WITH REGISTRATION Neither we nor any of the underwriters have authorized anyone to provide any information other than that contained in this prospectussupplement, the accompanying prospectus or in any free writing prospectus prepared by or on behalf of us to which we have referred you. When youmake a decision about whether to invest in our ADSs, you should not rely upon any information other than the information in this prospectussupplement. We take no responsibility for, and provide no assurances as to the reliability of, any other information that others may give you. Table of Contents ABOUT THIS PROSPECTUS SUPPLEMENT This document is part of an automatic shelf registration statement that we filed with the Securities and Exchange Commission (the “SEC”) using a“shelf” registration process available to us as a “well-known seasoned issuer,” as defined in Rule 405 under the Securities Act of 1933, as amended (the“Securities Act”) and consists of two parts. The first part is this prospectus supplement, including the documents incorporated by reference, whichdescribes the specific terms of this offering and also adds to and updates information contained in the accompanying prospectus. The second part, theaccompanying prospectus, including the documents incorporated by reference, gives more general information, some of which may not be applicable tothis offering. Generally, when we refer to the “prospectus” we are referring to both parts combined. If information in this prospectus supplement is inconsistent with the accompanying prospectus or with any document incorporated by referencethat was filed with the SEC before the date of this prospectus supplement, you should rely on this prospectus supplement. If any statement in thisprospectus supplement or the accompanying prospectus is inconsistent with a statement in another document that is incorporated by reference into thisprospectus and having a later date, the statement in the document having the later date modifies or supersedes the earlier statement. This prospectussupplement, the accompanying prospectus and the documents incorporated by reference into each inc