STAT+: Abivax ulcerative colitis drug shows strong efficacy, but cases of cancer raise concerns

STAT PlusBiotech Abivax ulcerative colitis drug shows strong efficacy, but cases of cancer raise concerns The late-stage trial has been closely watched Manage alerts for this article Email this article Share this article By Elaine ChenJune 1, 2026 Elaine Chen, a national biotech reporter, is the co-author of The Readout, a newsletter about the business, science, and politics of biotech. Elaine Chen[email protected]Elaine’s stories explore the boom in new obesity treatments, new drug payment models, the ways companies are affected by FDA changes, and the emerging psychedelics drug sector. She co-writes The Readout newsletter, and co-hosts STAT’s weekly biotech podcast, The Readout Loud. You can reach Elaine on Signal at elaineywchen.70. Abivax said Monday that its experimental treatment for ulcerative colitis showed significant efficacy in a closely watched maintenance trial, but shares of the company tanked in post-market trading as it reported a few cases of cancer among treated patients. The Phase 3 trial enrolled 580 patients who had responded in a pair of earlier, shorter trials. The participants were then followed for 44 weeks, and 50.8% of those taking the 25-milligram dose of the daily pill, called obefazimod, experienced clinical remission, while 51.3% of those taking the 50-mg dose did, compared with 10.4% of those on placebo.Advertisement The study appears to have posted the highest placebo-adjusted clinical remission rates observed in a long-term ulcerative colitis trial, Leerink analyst Thomas Smith wrote. STAT+ Exclusive Story Already have an account? Log in This article is exclusive to STAT+ subscribers Unlock this article — plus daily coverage and analysis of the biotech sector — by subscribing to STAT+. Already have an account? Log in Monthly $39 Totals $468 per year $39/month Get Started Totals $468 per year Starter $30 for 3 months, then $399/year $30 for 3 months Get Started Then $399/year Annual $399 Save 15% $399/year Get Started Save 15% 11+ Users Custom Savings start at 25%! Request A Quote Request A Quote Savings start at 25%! 2-10 Users $300 Annually per user $300/year Get Started $300 Annually per user View All Plans To read the rest of this story subscribe to STAT+. Subscribe Log In biotechnology, chronic diseases, drug development, Pharmaceuticals, STAT+ Submit a correction requestReprints Elaine Chen National Biotech Reporter Elaine’s stories explore the boom in new obesity treatments, new drug payment models, the ways companies are affected by FDA changes, and the emerging psychedelics drug sector. She co-writes The Readout newsletter, and co-hosts STAT’s weekly biotech podcast, The Readout Loud. You can reach Elaine on Signal at elaineywchen.70. Newsletter Your morning rundown of the science, politics, and money driving biotech today Recommended Biotech June 1, 2026 STAT Plus: At ASCO, talk of barriers to cancer care, new treatments, and other big takeaways The Readout June 1, 2026 STAT Plus: A turning point for pancreatic cancer patients Advertisement Biotech June 1, 2026 STAT Plus: Servier to buy Edgewise Therapeutics’ muscular dystrophy drug Biotech May 31, 2026 STAT Plus: A standing ovation for RevMed, and caution for Akeso Pharma May 31, 2026 Ultra-low doses could bring costly cancer treatments to more patients in poorer countries Subscriber Picks