Abivax Sinks as Cancer Cases Mar Crucial Bowel Disease Study (1)

Abivax SA shares plunged after cancer cases in a crucial clinical trial for a bowel disease drug threw the French biotech’s future into question.

The medicine was more effective than expected, helping patients with ulcerative colitis reach clinical remission rates 40% more than a placebo. But several volunteers enrolled in the study had cancer, including one who took the placebo. The shares slumped as much as 32%, bringing the stock back to its level of early October, before speculation about a potential takeover boosted Abivax’s market value beyond $10 billion.

The cancers raise the risk of a more difficult ...