Shares of French biotech company Abivax plummeted by 32% following the release of new trial data regarding its lead drug, obefazimod, aimed at treating ulcerative colitis. While the drug demonstrated a clinically meaningful efficacy with a remission rate of about 40%, concerns arose due to reported cancer cases among patients receiving the higher dosage. Jefferies analysts highlighted that this cancer signal complicates the drug's prospects, particularly given the absence of other significant data events in the near future. The trial results, published late Monday, stemmed from a 44-week maintenance study. Despite previous optimism surrounding obefazimod, which was considered a potential best-in-class treatment, these findings have raised doubts. Abivax is also exploring the drug's use for Crohn's disease, potentially tapping into a multi-billion-dollar market for Irritable Bowel Syndrome (IBS). The company's stock had previously surged nearly 1,700% in 2025, but had already seen a 7% decline prior to this latest update. Abivax remains a prime target for acquisition by larger pharmaceutical companies, led by CEO Marc de Garidel.