Bayer (XETRA: BAYN) announced that the US FDA has accepted its New Drug Application (NDA) and granted Priority Review designation for asundexian (BAY2433334), an investigational oral Factor XIa (FXIa) inhibitor, for the prevention of secondary stroke in patients following a non-cardioembolic ischemic stroke or transient ischemic attack (TIA). The submission is supported by results from the Phase III OCEANIC-STROKE trial, which were published in the New England Journal of Medicine in April 2026.
Priority Review compresses the FDA’s standard review timeline from 10-12 months to six months and is reserved for therapies that, if approved, would offer a meaningful improvement in the safety or effectiveness of treating a serious condition. Asundexian previously received FDA Fast Track Designation in 2023 for the same indication.
The OCEANIC-STROKE trial enrolled 12,327 patients with acute non-cardioembolic ischemic stroke or high-risk TIA, all receiving background antiplatelet therapy, in a randomized, double-blind, placebo-controlled design. Asundexian 50 mg once daily reduced the incidence of recurrent ischemic stroke to 6.2% versus 8.4% with placebo, corresponding to a cause-specific hazard ratio of 0.74 (95% CI 0.65–0.84; p < 0.001). The primary safety outcome — time to International Society on Thrombosis and Haemostasis (ISTH) major bleeding — showed no statistically significant increase versus placebo, a result that distinguishes the FXIa inhibitor class from conventional anticoagulants when added on top of antiplatelet therapy. The data were presented at the International Stroke Conference 2026 in New Orleans and published simultaneously in the New England Journal of Medicine.
Research context
Asundexian’s mechanism targets FXIa, a coagulation factor understood to contribute more to pathological thrombus formation than to normal hemostatic plug formation. That separation underpins the hypothesis that FXIa inhibition can reduce thrombotic events without a proportional increase in bleeding — a trade-off that has historically limited the use of anticoagulants in non-cardioembolic stroke, where atrial fibrillation or another cardioembolic source is absent and the benefit-risk calculus for full anticoagulation is less favorable. The OCEANIC-STROKE bleeding data, showing no excess ISTH major bleeding against placebo in a population already on antiplatelets, are consistent with that mechanistic hypothesis, though the trial was not powered as a direct head-to-head comparison against other anticoagulant classes.