• Interim intent to treat ("ITT") analysis from Study 108 supports strong durable clinical remission in moderately to severely active ulcerative colitis ("UC") patients treated with obefazimod
  
  
  
   
• Following two to four years of open-label treatment with 50 mg, 130 patients
  
  de-escalated to 25 mg, and at week 144, 68% (88/130) were in clinical remission and 80% (104/130) completed 144 weeks of treatment
  
  
  
   
• Patients in Study 108 were treated with obefazimod for up to seven years, with no new safety signals observed
  
  
  
   
• ABTECT Phase 3 maintenance trial results expected in late Q2 2026
  
  
  
   
• Cash, cash equivalents and short-term investments of €491.6M as of March 31, 2026; cash runway into Q4 2027
  
  
  
   

PARIS, France – May 22, 2026 – 10:05 PM CEST – Abivax SA (PARIS:FR) ("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 its financial results for the first quarter ended March 31, 2026. The first quarter financial statements, approved by the Company's Board of Directors on May 21, 2026, have been reviewed by the Company's statutory auditors, and the financial reports will be filed with the French and U.S. securities regulatory authorities, respectively, on May 22, 2026.

Study 108: Three-Year Interim Analysis of Long-Term Obefazimod Treatment and Dose De-Escalation in Patients with Moderately to Severely Active UC

In this open-label maintenance ("OLM") trial, patients who had completed the four-year Phase 2a or two-year Phase 2b OLM trials, where they had received 50 mg of once-daily obefazimod, were given the opportunity to continue receiving obefazimod at a reduced dose of 25 mg daily for up to five additional years (provided they met the eligibility criteria of Mayo Endoscopic Subscore = 0 or 1). A total of 130 patients entered the trial and as of the January 5, 2026 cutoff date, 80% (104/130) were still enrolled and completed the full 144-week evaluation.

At study baseline, 89% (116/130) of patients were in clinical remission. At weeks 48, 96 and 144 of treatment, 73% (95/130), 69% (90/130), and 68% (88/130) of patients evaluated were in clinical remission, respectively. Clinical remission, inclusive of endoscopic subscore, was evaluated in the ITT population using non-responder imputation. Similar trends were observed with other efficacy analyses, and no new safety signals were observed.