Abivax SA

Abivax Presents Business Updates and First Half 2026 Financial Results PARIS, France – September 21, 2026 – 10:05 PM CEST – Abivax SA (Euronext Paris: FR0012333284 – ABVX / Nasdaq – ABVX) (“Abivax” or the “Company”), a clinical-stage biotechnology company focused on developing therapeutics that harness the body’s natural regulatory mechanisms to stabilize the immune response in patients with chronic inflammatory diseases, reported today business updates and financial results for the six months ended June 30, 2026. S. securities regulatory authorities on September 21, 2026.

A brief presentation summarizing these business and financial updates is available on the Investor Relations section of Abivax’s website. , Chief Medical Officer, will be leaving Abivax in the fourth quarter of 2026. , who has led Global Medical Affairs since 2023, will succeed Dr. Cataldi as Chief Medical Officer, leading the medical organization as Abivax advances toward potential commercialization. Dr. Rabbat brings extensive biopharmaceutical industry experience, including deep expertise in Inflammatory Bowel Disease (“IBD”) and experience supporting therapies through commercialization and launch.

His combination of industry experience, therapeutic area expertise and commercial-stage medical leadership will be particularly valuable as Abivax prepares for the potential commercialization of obefazimod. Abivax thanks Dr. Cataldi for his important contributions to the Company, including his leadership through the late-stage development of obefazimod and advancement of the program toward its planned NDA submission. Abivax has also appointed Tim Kelly as Chief Technical Officer. Mr. Kelly will lead the Company’s commercial CMC, Quality and Information Technology functions, further strengthening the infrastructure supporting Abivax’s continued growth and potential transition to a commercial-stage organization.

Most recently, he served as Chief Technology Officer of Caribou Biosciences and previously was the CEO of Oxford Biomedica Solutions. He also held senior leadership roles at Homology Medicines, Shire, UCB Pharma and Biogen. Both executive appointments are effective immediately. “As we prepare Abivax for its next phase of growth and the potential commercialization of obefazimod, we are continuing to strengthen the leadership and capabilities needed to support that evolution,” said Marc de Garidel, MBA, Chief Executive Officer of Abivax . “We are deeply grateful to Fabio for his important contributions to Abivax and his leadership as we advanced obefazimod through late-stage development toward regulatory filing.

Chris brings extensive experience in IBD and deep relationships with key opinion leaders, which will be critical as he leads our medical organization through the pre-commercial phase and toward potential commercialization. 4 million 2 Includes both current and non-current portions of borrowings, convertible loan notes, derivative instruments, and lease liabilities ***** About Abivax Abivax is a clinical-stage biotechnology company focused on developing therapeutics that harness the body’s natural regulatory mechanisms to stabilize the immune response in patients with chronic inflammatory diseases.

Based in France and the United States, Abivax’s lead drug candidate, obefazimod (ABX464), is in Phase 3 clinical trials for the treatment of moderately to severely active ulcerative colitis. com FORWARD-LOOKING STATEMENTS This press release contains forward-looking statements, forecasts and estimates, including those relating to the Company’s business. Words such as “anticipate,” “expect,” “future,” “potential,” “will” and variations of such words and similar expressions are intended to identify forward-looking statements. These forward-looking statements include statements concerning the potential therapeutic benefit of obefazimod, the expected timing for completion of the Phase 2b ENHANCE-CD induction trial of obefazimod and the availability and timing of results therefrom, the timing of regulatory filings including an NDA submission for obefazimod in UC, Abivax’s expectations for regulatory approval and commercialization of obefazimod for UC, the expected increase in costs associated with preparing for commercial launch of obefazimod, including the anticipated PDUFA date, Abivax’s cash runway, and other statements that are not historical fact.

Although Abivax’s management believes that the expectations reflected in such forward-looking statements are reasonable, investors are cautioned that forward-looking information and statements are subject to various risks, contingencies and uncertainties, many of which are difficult to predict and generally beyond the control of Abivax, that could cause actual results and developments to differ materially from those expressed in, or implied or projected by, the forward-looking information and statements. S. ” These risks, contingencies and uncertainties include, among other things, the uncertainties inherent in research and development, future clinical data and analysis, decisions by regulatory authorities, such as the FDA or the EMA, regarding whether and when to approve any drug candidate, as well as their decisions regarding labelling and other matters that could affect the availability or commercial potential of such product candidates, and the availability of funding sufficient for the Company’s foreseeable and unforeseeable operating expenses and capital expenditure requirements.

Special consideration should be given to the potential hurdles of clinical and pharmaceutical development, including further assessment by the Company and regulatory agencies and IRBs/ethics committees following the assessment of preclinical, pharmacokinetic, carcinogenicity, toxicity, CMC and clinical data. Furthermore, these forward-looking statements, forecasts and estimates are made only as of the date of this press release. Readers are cautioned not to place undue reliance on these forward-looking statements.