By Puyaan Singh
June 29 (Reuters) – Abivax said on Monday its experimental ulcerative colitis drug helped harder-to-treat groups of patients achieve remission, sending U.S.-listed shares of the Paris-based company soaring 26.4% in extended trading.
The company said 37.2% of patients who had not responded to an initial induction treatment of obefazimod achieved clinical remission after continued treatment at a 50 milligram dose at week 44, while 34.5% achieved endoscopic remission.
Separately, among patients who relapsed during the first part of the maintenance phase, increasing the dose to 50 mg recaptured clinical remission in 45.5%, Abivax said.
The results follow June 1 data from the same trial where 50.8% of patients on the 25 mg dose and 51.3% on the 50 mg dose achieved clinical remission, compared with 10.4% on placebo.
Shares in Abivax sank after the June 1 readout as investors focused on cancer cases reported in patients taking the higher dose, though investigators considered the cases unrelated to treatment.
Abivax said the expanded safety dataset, covering 1,704 patient-years of drug exposure, showed that cancer rates were in line with those normally seen in ulcerative colitis patients.
Abivax’s head of regulatory affairs, Keith Fournier, said that “four independent former FDA senior leaders … considered it highly unlikely that (the FDA’s strictest) boxed warning would be required.” The experts don’t expect significant additional testing or referral requirements, Fournier said.
Obefazimod is an oral miR-124 enhancer designed to regulate inflammatory responses. Abivax has said it plans to submit a U.S. marketing application in late 2026.
(Reporting by Puyaan Singh in Bengaluru; Editing by Vijay Kishore and Sahal Muhammed)
