FDA Grants Priority Review to Asundexian for Secondary Prevention After Ischemic Stroke

On May 19, 2026, the US Food and Drug Administration (FDA) granted priority review to asundexian for secondary stroke prevention after non-cardioembolic ischemic stroke or transient ischemic attack (TIA).1

Announced by parent company Bayer, the filing is based on phase 3 OCEANIC-STROKE data presented earlier this year and published in The New England Journal of Medicine. If approved, asundexian would enter a treatment landscape in which antiplatelet therapy remains standard for most patients with non-cardioembolic ischemic stroke or TIA, but recurrent events continue to occur despite guideline-based care.1,2,3

“Secondary stroke remains a serious and persistent challenge, and the FDA’s Priority Review designation underscores the urgency of advancing potential new approaches in secondary stroke prevention,” Yesmean Wahdan, MD, senior vice president of medical affairs at Bayer, said in a statement. “We are proud of this important milestone that builds our long-standing commitment to innovation in anti-thrombotic therapies and look forward to collaborating with the FDA as we work to bring asundexian to patients in need.”1

About Asundexian

Asundexian is an investigational oral factor XIa inhibitor. Factor XIa has emerged as a target in antithrombotic development because of the hypothesis that it may contribute more to pathologic thrombosis than to physiologic hemostasis, potentially allowing reduction of ischemic events with less bleeding than traditional anticoagulants. That concept remains under study across several cardiovascular settings, and no factor XIa inhibitor is yet established as standard therapy for secondary prevention after ischemic stroke.

The disease burden underlying the NDA is substantial. Stroke remains a leading cause of death and disability in the United States, and recurrent ischemic events are common after an index stroke or TIA. Current AHA/ASA guidance for noncardioembolic ischemic stroke generally supports antiplatelet-based secondary prevention rather than anticoagulation, except in selected circumstances tied to stroke mechanism or comorbid conditions. In that context, an FDA review of a novel antithrombotic mechanism for this population is clinically notable.3

OCEANIC-STROKE Results

Asundexian’s NDA is supported by positive findings from the global pivotal phase 3 OCEANIC-STROKE trial, which compared asundexian on top of standard antiplatelet therapy to placebo in patients who recently had a non-cardioembolic ischemic stroke or TIA. The study was conducted across 741 locations worldwide and included patients with acute non-cardioembolic stroke or high-risk TIA and systemic or cerebrovascular atherosclerosis or acute non-lacunar infarct. Patients with ischemic stroke ≤7 days before index or a history of atrial fibrillation/flutter, or left ventricular thrombus, among other criteria, were excluded.1,4

Enrolled patients would receive either 50mg of asundexian daily or matched placebo, both of which were administered on top of standard anticoagulant therapy. The study’s primary efficacy endpoint was time to first occurrence of ischemic stroke, and the primary safety endpoint was time to first occurrence of International Society on Thrombosis and Hemostasis (ISTH) major bleeding.4

A total of 12,327 patients underwent randomization, with 6162 assigned to the asundexian arm and 6165 to placebo. Both arms were followed for a median of 19 months, during which the incidence of ischemic stroke was substantially lower in the treatment arm than the placebo arm (6.2% vs 8.4%; cause-specific hazard ratio [HR], 0.74; 95% CI, 0.65-0.84; P <.001). The incidence of death from cardiovascular causes, myocardial infarction, or stroke was also lower among the asundexian group.2

The incidence of major bleeding was similar across the asundexian and placebo groups (1.9% and 1.7%; cause-specific HR, 1.1; 95% CI, 0.85-1.44). Adverse events occurred in 69.3% of the asundexian group and 70.1% in the placebo group. Serious adverse event rates were 19.2% and 19.5%, respectively.2

Remaining questions

Asundexian’s development has drawn attention because prior antithrombotic intensification strategies in non-cardioembolic stroke have often improved ischemic protection at the cost of more bleeding, or failed to show a favorable net clinical profile. That history is part of the rationale for studying factor XIa inhibition, but it also means regulators and clinicians will likely focus closely on absolute benefit, intracranial and major bleeding, and applicability to routine poststroke care.3

In the present announcement, Bayer has not confirmed a Prescription User Drug Fee Act (PDUFA) date for asundexian’s approval.1

References

1. Bayer Granted Priority Review by U.S. FDA for Asundexian in Patients After a Non-Cardioembolic Ischemic Stroke or Transient Ischemic Attack. Business Wire. May 19, 2026. Accessed May 19, 2026. https://www.businesswire.com/news/home/20260518787299/en/Bayer-Granted-Priority-Review-by-U.S.-FDA-for-Asundexian-in-Patients-After-a-Non-Cardioembolic-Ischemic-Stroke-or-Transient-Ischemic-Attack

2. OCEANIC-STROKE trial publication. N Engl J Med. Published online 2026. Accessed via article link in press release. https://www.nejm.org/doi/10.1056/NEJMoa2513880

3. Kleindorfer DO, Towfighi A, Chaturvedi S, et al. 2021 guideline for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline from the American Heart Association/American Stroke Association. Stroke. 2021;52(7):e364-e467. https://doi.org/10.1161/STR.0000000000000375

4. Bayer. A Study to Test Asundexian for Preventing a Stroke Caused by a Clot in Participants After an Acute Ischemic Stroke or After a High-risk Transient Ischemic Attack, a So-Called Mini Stroke (OCEANIC-STROKE). ClinicalTrials.gov Identifier: NCT05686070. Updated November 12, 2025. Accessed May 19, 2026. https://clinicaltrials.gov/study/NCT05686070