Abivax Shares Drop 44% After Obefazimod Trial Shows Higher-Dose Cancer Signals
ABVX•Abivax shares fell 44% after its obefazimod ulcerative colitis trial reported non-melanoma skin cancers in patients on the higher-dose arm, despite 51% remission at week 44 versus 10.4% placebo. The company says cancer events were rare, age-related, unrelated to the drug and will file for FDA approval by late 2026.
1. Trial Data Shows Efficacy and Safety Signals
In its 580-patient phase III ulcerative colitis trial, obefazimod achieved clinical remission in 51% of patients at week 44 on both 25 mg and 50 mg doses versus 10.4% on placebo. The drug met all key secondary endpoints, including endoscopic healing and histologic improvement, but reported non-melanoma skin cancers in the higher-dose arm.
2. Shares Plunge on Malignancy Reports
Shares of Abivax fell 44%—the company’s largest one-day slide ever—following reports of malignancies in the trial. Multiple analysts slashed price targets, reflecting concern over the safety signals’ potential impact on approval prospects and commercial outlook.
3. Company Emphasizes Rare, Age-Related Events and FDA Timeline
Abivax stated that malignancy events were rare, consistent with expected age-related risks, and largely unrelated to obefazimod. The company remains on track to file for FDA approval by late 2026 and highlighted otherwise favorable safety and efficacy data.
