Abivax ulcerative colitis drug shows strong efficacy, but safety concerns arise

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.

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.

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