Biotech takeover target Abivax sinks over 40% as cancer cases cloud trial data for bowel disease drug
Shares of Abivax tumbled as much 40% after it reported fresh data on its lead asset, a drug for ulcerative colitis, wiping out billions in
Shares of Abivax tumbled as much 40% after it reported fresh data on its lead asset, a drug for ulcerative colitis, wiping out billions in market cap and raising questions over how a potential takeover of the French biotech could unfold. The medicine met its endpoints of demonstrating clinically meaningful efficacy and a placebo-adjusted remission rate of about 40% for both doses tested, but also showed that there were cancer cases among patients taking the higher dose.
"[The] cancer signal complicates matters," a Jefferies analyst said. "Even if unrelated noise, we think the overhang will be real, especially considering absence of other value-inflecting data events over the next [year]." In the study cohort, there was one reported case each of prostate cancer, breast cancer, and colonic dysplasia, which Abivax said were considered unrelated to treatment by investigators, with no organ-specific clustering observed.
There were also four cases of skin cancer on the higher 50 mg dose, of which two were deemed not or unlikely related to the drug, and the other two had a medical history of skin cancer, Abivax said. The Jefferies analysts said that "a reasonable explanation" for the cancer cases was plausible but "doesn't seem like an easily dismissed overhang," and downgraded the stock to Hold from Buy.
The Paris-listed stock gained nearly 1,700% in 2025, but shares had fallen 7% coming into Tuesday trading. It was last trading down 40.5%.
The BriefWire