SCHEDULE 13G/A 0002005369 XXXXXXXX LIVE 1 Ordinary Shares, nominal value Euro 0.01 per share 12/31/2025 0001956827 Abivax S.A. 00370M103 7 BD HAUSSMANN PARIS I0 75009 Rule 13d-1(c) Invus Public Equities, L.P. D0 3922995.00 0.00 3922995.00 0.00 3922995.00 N 5.0 PN Invus Public Equities, L.P. directly held 3,922,995 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares") of Abivax S.A. (the "Issuer"). There is no CUSIP number assigned to the Shares. The CUSIP Number 00370M103 has been assigned to the American Depositary Shares ("ADSs") of the Issuer, which are quoted on the Nasdaq Global Market under the symbol "ABVX". Each ADS represents 1 Share. Invus Public Equities Advisors, LLC DE 3922995.00 0.00 3922995.00 0.00 3922995.00 N 5.0 OO Invus Public Equities, L.P. directly held 3,922,995 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares") of Abivax S.A. (the "Issuer"). There is no CUSIP number assigned to the Shares. The CUSIP Number 00370M103 has been assigned to the American Depositary Shares ("ADSs") of the Issuer, which are quoted on the Nasdaq Global Market under the symbol "ABVX". Each ADS represents 1 Share. Invus Global Management, LLC DE 3922995.00 0.00 3922995.00 0.00 3922995.00 N 5.0 OO Invus Public Equities, L.P. directly held 3,922,995 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares") of Abivax S.A. (the "Issuer"). There is no CUSIP number assigned to the Shares. The CUSIP Number 00370M103 has been assigned to the American Depositary Shares ("ADSs") of the Issuer, which are quoted on the Nasdaq Global Market under the symbol "ABVX". Each ADS represents 1 Share. Siren, L.L.C. DE 3922995.00 0.00 3922995.00 0.00 3922995.00 N 5.0 OO Invus Public Equities, L.P. directly held 3,922,995 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares") of Abivax S.A. (the "Issuer"). There is no CUSIP number assigned to the Shares. The CUSIP Number 00370M103 has been assigned to the American Depositary Shares ("ADSs") of the Issuer, which are quoted on the Nasdaq Global Market under the symbol "ABVX". Each ADS represents 1 Share. Raymond Debbane R1 3922995.00 0.00 3922995.00 0.00 3922995.00 N 5.0 IN Invus Public Equities, L.P. directly held 3,922,995 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares") of Abivax S.A. (the "Issuer"). There is no CUSIP number assigned to the Shares. The CUSIP Number 00370M103 has been assigned to the American Depositary Shares ("ADSs") of the Issuer, which are quoted on the Nasdaq Global Market under the symbol "ABVX". Each ADS represents 1 Share. Abivax S.A. 7-11 boulevard Haussmann, 75009 Paris, France See Item 2(c) below. See Item 2(c) below. (i) Invus Public Equities, L.P. ("Invus Public Equities") 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Bermuda limited partnership (ii) Invus Public Equities Advisors, LLC ("Invus PE Advisors") 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Delaware limited liability company (iii) Invus Global Management, LLC ("Global Management") 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Delaware limited liability company (iv) Siren, L.L.C. ("Siren") c/o The Invus Group, LLC, 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Delaware limited liability company (v) Mr. Raymond Debbane 750 Lexington Avenue, 30th Floor, New York, NY 10022 Citizenship: Panama The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." Y As of December 31, 2025, Invus Public Equities directly held 3,922,995 Ordinary Shares, nominal value Euro 0.01 per share (the "Shares") of Abivax S.A. (the "Issuer"). Invus PE Advisors, as the general partner of Invus Public Equities, controls Invus Public Equities and, accordingly, may be deemed to beneficially own the Shares directly held by Invus Public Equities. Global Management, as the managing member of Invus PE Advisors, controls Invus PE Advisors and, accordingly, may be deemed to beneficially own the Shares that Invus PE Advisors may be deemed to beneficially own. Siren, as the managing member of Global Management, controls Global Management and, accordingly, may be deemed to beneficially own the Shares that Global Management may be deemed to beneficially own. Mr. Raymond Debbane, as the managing member of Siren, controls Siren and, accordingly, may be deemed to beneficially own the Shares that Siren may be deemed to beneficially own. There is no CUSIP number assigned to the Shares. The CUSIP Number 00370M103 has been assigned to the American Depositary Shares ("ADSs") of the Issuer, which are quoted on the Nasdaq Global Market under the symbol "ABVX". Each ADS represents 1 Share. As of December 31, 2025, each of the Reporting Persons may be deemed to be the beneficial owner of the Shares listed on such Reporting Person's cover page. Calculations of the percentage of Shares beneficially owned are based on 77,830,067 Shares outstanding as of September 30, 2025, as reported in the Issuer's Form 6-K filed with the Securities and Exchange Commission on December 15, 2025. See each cover page hereof. See each cover page hereof. See each cover page hereof. See each cover page hereof. Y Y Y Y Y N Each of the Reporting Persons hereby makes the following certification: By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Invus Public Equities, L.P. /s/ Raymond Debbane 02/13/2026 Invus Public Equities Advisors, LLC /s/ Raymond Debbane 02/13/2026 Invus Global Management, LLC /s/ Raymond Debbane 02/13/2026 Siren, L.L.C. /s/ Raymond Debbane 02/13/2026 Raymond Debbane /s/ Raymond Debbane 02/13/2026