Abivax's Ulcerative Colitis Drug Shows Promise in Phase 3 Trials, Stock Soars

French biotech company Abivax has reported positive Phase 3 results for its experimental ulcerative colitis medicine, obefazimod, causing the company's stock to surge over 500% on Wednesday. The drug, which represents a new approach in treating inflammatory bowel disease (IBD), has shown significant potential in a market projected to reach $30 billion by 2030.

Trial Results and Clinical Significance

Abivax conducted two studies, ABTECT-1 and ABTECT-2, involving patients with moderately to severely active ulcerative colitis who had not responded adequately to previous treatments. The 50 milligram dose of obefazimod achieved a pooled 16.4% placebo-adjusted clinical remission rate at week 8, surpassing the results observed in Phase 2 testing.

The ABTECT study program, one of the largest ever undertaken in ulcerative colitis, includes more than 600 sites worldwide and 1,275 patients. While the 50 milligram dose met its primary endpoints and all key secondary endpoints, the 25 milligram dose did not reach statistical significance for clinical remission in the ABTECT-2 study. However, Abivax reported that the pooled clinical response rate for the lower dose suggested potential remission with extended treatment.

Market Impact and Future Plans

Following the announcement of these results, Abivax's shares experienced a dramatic increase, jumping from 8.90 euros to approximately 56 euros on the Paris exchange. The positive outcome has positioned obefazimod at the forefront of oral drugs for treating inflammatory bowel disease, according to Leerink Partners analyst Thomas J. Smith.

Abivax is currently conducting a 44-week maintenance trial, with topline results expected in the second quarter of 2026. Pending positive outcomes, the company plans to submit applications to U.S. and European regulators in the second half of 2026.

Smith's team at Leerink now forecasts peak sales of about $4 billion for obefazimod in both ulcerative colitis and Crohn's disease, up from an earlier estimate of $2.6 billion. The drug's "compelling balance of efficacy, safety and convenience" has contributed to this optimistic projection.

Competitive Landscape in IBD Treatment

Abivax's success comes at a time of increasing interest in the IBD treatment market from major pharmaceutical companies. Merck & Co., Roche, Pfizer, and Eli Lilly have all made significant investments in recent years, acquiring companies with experimental drugs targeting inflammatory conditions, including ulcerative colitis.

Eli Lilly is currently awaiting data from its own experimental drug, MORF-057, highlighting the competitive nature of this growing market. As the first in its class, obefazimod offers a novel approach to treating a disease that has attracted substantial attention from drugmakers, potentially reshaping the landscape of IBD treatment options.