Abivax Shares Fall 30% After 51% Ulcerative Colitis Remission, Cancer Concerns
ABVX•Abivax’s obefazimod achieved 51% clinical remission at Week 44 in 580 adults with moderate-to-severe ulcerative colitis versus 10.4% on placebo. Shares plunged over 30% after-hours on reports of rare non-melanoma skin cancers in the higher-dose arm, though the FDA submission remains scheduled for late 2026.
1. Maintenance Trial Results
In a late-stage maintenance trial, obefazimod delivered 51% clinical remission at Week 44 for both 25 mg and 50 mg doses in 580 adults with moderate-to-severe ulcerative colitis, compared with 10.4% on placebo. The treatment also met all key secondary endpoints, including endoscopic healing and sustained symptom relief without steroids.
2. Safety Profile and Cancer Reports
Overall safety was favorable over 44 weeks, with most adverse events mild or moderate. A small number of non-melanoma skin cancers emerged in the higher-dose arm, primarily in patients over 60; Abivax said these were consistent with age-related incidence and largely unrelated to obefazimod.
3. Investor Reaction and Sentiment
Shares of Abivax fell more than 30% after-hours trading following the trial update, driven by concern over the reported malignancies. Retail sentiment swung sharply bullish on the lower price levels, with trading volumes and message activity spiking.
4. Regulatory Pathway and Outlook
Abivax remains on track to file for FDA approval of obefazimod in ulcerative colitis by late 2026. The company plans to present additional trial data at upcoming medical meetings, and expects Crohn’s disease study results by mid-2027.
