Bayer's Asundexian Cuts Recurrent Stroke 26% in Phase 3 OCEANIC-STROKE Trial

Bayer's experimental blood thinner asundexian cut the risk of a second ischemic stroke by 26% compared with placebo in the Phase 3 OCEANIC-STROKE trial, with no increase in major bleeding, the company said on February 5 as it presented the full results at the International Stroke Conference 2026 in New Orleans, in a release distributed by Business Wire and read via BioSpace.

Asundexian is an oral, once-daily inhibitor of Factor XIa, a clotting protein. Bayer had already reported topline results from the study, and the full data clear the way for the company to seek regulatory approvals, pharmaphorum reported. The drug is not approved anywhere and holds FDA Fast Track designation for stroke prevention after a non-cardioembolic ischemic stroke.

Trial results

OCEANIC-STROKE was a multicenter, randomized, double-blind, placebo-controlled, event-driven trial that enrolled 12,327 people who had had a non-cardioembolic ischemic stroke or a high-risk transient ischemic attack. Participants took asundexian 50 mg or placebo, in both cases on top of antiplatelet therapy. The primary endpoint was time to ischemic stroke, and the primary safety endpoint was major bleeding.

Asundexian reduced ischemic stroke by 26% (cause-specific hazard ratio 0.74; 95% CI 0.65–0.84; p<.0001), Bayer said, and the effect was consistent across age, sex, type of index event, stroke subtype, stroke severity and the antiplatelet strategy used. Stroke of any kind, ischemic or hemorrhagic, fell by the same 26%, occurring in 6.6% of the asundexian group versus 8.8% on placebo. The drug also met secondary composite endpoints of cardiovascular death, heart attack or stroke, and of death from any cause, heart attack or stroke.

ISTH major bleeding occurred in 1.9% of patients on asundexian and 1.7% on placebo (hazard ratio 1.10; 95% CI 0.85–1.44), a difference Bayer described as no increase. The company said bleeding rates on its other prespecified safety measures, including minor bleeding, hemorrhagic stroke, symptomatic intracranial hemorrhage and fatal bleeding, were similar to placebo.

"The consistent reduction in secondary events with asundexian across all types of strokes included in the trial, is particularly striking," said Ashkan Shoamanesh, co-principal investigator of the study and a senior scientist at the Population Health Research Institute, in the release.

A recovery for the program

Bayer called OCEANIC-STROKE the first successfully completed Phase III study of a Factor XIa inhibitor to show superiority over placebo in reducing recurrent ischemic stroke. pharmaphorum noted that the result revives a drug whose future was in doubt after it failed an earlier Phase 3 trial in atrial fibrillation.

The company is racing Bristol Myers Squibb and Johnson & Johnson, whose Factor XIa candidate milvexian is in Phase 3 trials in atrial fibrillation and stroke, pharmaphorum reported. Antibody-based Factor XIa drugs, including Novartis and Anthos' abelacimab, are also in development.

Bayer said it will submit the OCEANIC-STROKE data to health authorities to seek marketing authorization for asundexian.