Abivax SA ADR美股招股说明书(2025-07-23版)

We are offeringof our American Depositary Shares (“ADSs”), each representing one ordinary share, €0.01nominal value 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 July23, 2025, the last reportedsale price of our ordinary shares on Euronext Paris was €54.30 per ordinary share and the last reported sale price of our ADSs onNasdaq was $68.60 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 onpageS-9ofthis prospectus supplement under the caption “Risk Factors” and under the caption “Risk Factors”on page5 of the accompanying prospectus and in our most recent Annual Report onForm20-Fandany 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. PerADSTotalOffering price$$Underwriting commissions(1)$$Proceeds to us (before expenses)$$ (1)We refer you to “Underwriting” beginning on pageS-28of this prospectus supplement for additional information regardingunderwriting compensation. Delivery of the ADSs is expected to be made on or about July28, 2025, through the book-entry facilities of The DepositoryTrust Company. We have agreed to issue, at the option of the underwriters, within 30 days from the date of the underwritingagreement to be executed between us and the underwriters, up to an aggregate of $60,000,000 of additional ADSs to be sold tothe several underwriters at the applicable offering price. GuggenheimSecurities LeerinkPartners BTIG VanLanschotKempen 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 PROCEEDSPLAN OF DISTRIBUTIONDESCRIPTION OF SHARE CAPITAL LIMITATIONS AFFECTING SHAREHOLDERS OF A FRENCH COMPANY DESCRIPTION OF AMERICAN DEPOSITARY SHARES DESCRIPTION OF WARRANTS TAXATION LEGAL MATTERS EXPERTS ENFORCEMENT OF CIVIL LIABILITIES We have not authorized anyone to provide any information other than that contained in this prospectus supplement, the accompanying prospectusor in any free writing prospectus prepared by or on behalf of us to which we have referred you. We take no responsibility for, and provide no assurancesas 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”), usinga “shelf” registration process available to us as a “well-known seasoned issuer,” as defined in Rule 405 under the Securities Act and consists of twoparts. The first part is this prospectus supplement, including the documents incorporated by reference, which describes the specific terms of this offeringand also adds to and updates information contained in the accompanying prospectus. The second part, the accompanying prospectus, including thedocuments incorporated by reference, gives more general information, some of which may not be applicable to this offering. Generally, when we refer tothe “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 include important information about us, the ordinaryshares (including in the form of ADSs) being offered and other information that you should know before investing in our ordinary shares (including inthe form of ADSs). You should also read and consider informat