Shares of Abivax rose sharply Monday after the company disclosed positive results from its Phase 3 ABTECT maintenance study evaluating obefazimod in patients with ulcerative colitis. The market reaction followed topline data showing both tested doses substantially outperformed placebo on the trial's primary measure of clinical remission at Week 44.
In the ABTECT maintenance trial, once-daily obefazimod at 25 mg achieved a clinical remission rate of 50.8% at Week 44, while the 50 mg dose produced a 51.3% remission rate. The placebo group recorded a 10.4% remission rate. The placebo-adjusted clinical remission differences were 39.3% for the 25 mg arm and 40.3% for the 50 mg arm.
The randomized study enrolled 580 participants who had been clinical responders following the prior 8-week induction phase. According to the company, both dosing regimens met all predefined key secondary endpoints, which included measures of endoscopic improvement, endoscopic remission, and corticosteroid-free clinical remission.
Detailed secondary endpoint results highlighted robust endoscopic effects for the higher dose. The 50 mg cohort showed endoscopic improvement in 64.1% of patients versus 12.5% in the placebo arm, representing a placebo-adjusted improvement of 51.0%. Endoscopic remission was observed in 47.7% of patients on the 50 mg dose compared with 9.9% of those receiving placebo.
Safety data from the 44-week maintenance period indicated a favorable profile with no new safety signals identified. Rates of treatment-emergent adverse events were reported as 71.8% in the 50 mg arm, 58.0% in the 25 mg arm, and 50.0% in the placebo group. The company reported no deaths during the trial and noted that serious infections occurred in less than 1% of patients across all treatment groups.
Looking ahead, Abivax said it intends to submit a New Drug Application to the U.S. Food and Drug Administration for obefazimod in ulcerative colitis in the fourth quarter of 2026. The company also indicated that topline results from a Phase 2b induction trial in Crohn's disease are expected around mid-2027.
Market reaction and context
Market activity reflected investor optimism following the ABTECT maintenance data release, with Abivax stock climbing about 20% on the announcement. The results represent a significant efficacy signal from a late-stage maintenance study and set a timeline for regulatory activity tied to an NDA submission targeted for late 2026.
What the data show
- The primary endpoint of clinical remission at Week 44 was met for both 25 mg and 50 mg doses, each achieving roughly 51% remission versus 10.4% for placebo.
- Key secondary endpoints - including endoscopic measures and corticosteroid-free remission - were also met by both doses.
- Safety signals reported were consistent with prior observations, with no new safety concerns identified across the 44-week maintenance period.
Implications for stakeholders
For investors, the data provide a clear efficacy readout from a Phase 3 maintenance trial, which supports the company’s plan to pursue regulatory filing in the United States. For clinicians and patients, the results signal potential maintenance therapy efficacy for obefazimod, subject to regulatory review. The broader healthcare and biotechnology sectors may monitor follow-on regulatory milestones and the forthcoming Crohn's disease induction data.