Abivax shares plunge more than 35% as cancer cases reported in a Phase 3 trial overshadow strong efficacy results for ulcerative colitis drug.

Abivax said its experimental treatment for ulcerative colitis showed significant efficacy in a closely watched trial, but shares of the company tanked on safety concerns.

A handful of cancer cases reported among treatment recipients overshadowed efficacy results analysts described as “best-in-disease” and sent shares down more than 30%.