FDA Grants Priority Review to Asundexian for Secondary Stroke Prevention

The US Food and Drug Administration (FDA) has accepted Bayer’s New Drug Application for asundexian, an investigational oral factor XIa (FXIa) inhibitor, and granted Priority Review for secondary stroke prevention after noncardioembolic ischemic stroke or transient ischemic attack (TIA). The application is supported by the phase 3 OCEANIC-STROKE trial, which Bayer described as positive and said was presented at the International Stroke Conference 2026 and published in The New England Journal of Medicine.¹

“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 US Medical Affairs at Bayer, said in the announcement.¹ If approved, asundexian would enter a treatment area in which antiplatelet therapy and aggressive vascular risk reduction remain central, but recurrent ischemic events continue to occur despite guideline-directed care.

The regulatory submission covers prevention of recurrent stroke in patients after noncardioembolic ischemic stroke or TIA. The FDA previously granted Fast Track designation to asundexian in 2023 for this potential use, Bayer said in the press release.¹ Priority Review shortens the FDA review goal for applications that, if approved, may offer meaningful improvements in treatment, diagnosis, or prevention of serious conditions; it does not indicate approval or establish clinical benefit.

OCEANIC-STROKE is a global, pivotal phase 3 trial. The company announcement did not report absolute event rates, hazard ratios, prespecified primary end point details, or rates of major bleeding or intracranial hemorrhage. The release stated only that the trial results were positive and formed the basis of the NDA.¹ For clinicians, interpretation of the application will therefore depend on the full peer-reviewed report and FDA review materials, particularly the magnitude of recurrent stroke reduction and the bleeding profile when asundexian is used in the poststroke population.

Stroke remains a major cause of mortality and disability in the US. The American Heart Association’s 2024 statistical update lists stroke among the leading causes of death, with ischemic stroke accounting for most cases.² Recurrent stroke risk is highest soon after the index event but persists over subsequent years, making secondary prevention a long-term management issue in primary care, neurology, cardiology, and rehabilitation settings.

Current US secondary prevention guidance emphasizes determining stroke mechanism and tailoring therapy accordingly. For noncardioembolic ischemic stroke or TIA, antiplatelet therapy is generally preferred over oral anticoagulation, with short-term dual antiplatelet therapy reserved for selected patients with minor ischemic stroke or high-risk TIA and longer-term treatment usually involving single antiplatelet therapy plus intensive control of blood pressure, lipids, diabetes, smoking, and other vascular risk factors.³ An oral anticoagulant-like strategy that reduces thrombotic events without substantially increasing bleeding would represent a clinically important advance, but that balance must be demonstrated in the target population.

Asundexian inhibits FXIa, a component of the intrinsic coagulation pathway. FXIa inhibition is being studied because the pathway may contribute more to pathologic thrombosis than to normal hemostasis, raising the possibility of antithrombotic efficacy with less bleeding than conventional anticoagulants. That hypothesis remains drug- and indication-specific. In the phase 2b PACIFIC-STROKE trial of patients with acute noncardioembolic ischemic stroke, asundexian did not show a significant dose-response reduction in the composite primary end point of covert brain infarction or recurrent symptomatic ischemic stroke, although bleeding findings helped support continued study in larger trials.⁴

The FDA review will need to clarify how OCEANIC-STROKE’s efficacy findings compare with contemporary antiplatelet-based secondary prevention and whether any benefit is consistent across clinically relevant subgroups, including index TIA vs ischemic stroke, stroke subtype, background antiplatelet regimen, age, kidney function, and baseline bleeding risk. Practical questions also remain about duration of therapy, concomitant aspirin or dual antiplatelet use, perioperative management, and reversal strategies if major bleeding occurs.

For now, asundexian remains investigational in the US for secondary prevention after noncardioembolic ischemic stroke or TIA. Priority Review places the application on an accelerated FDA review timeline, but clinical adoption will depend on the agency’s assessment of the full efficacy and safety data and any labeling restrictions if approval is granted.

References

1. Bayer. Bayer granted Priority Review by U.S. FDA for asundexian in patients after a non-cardioembolic ischemic stroke or transient ischemic attack. BusinessWire. Published 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. Martin SS, Aday AW, Almarzooq ZI, et al. 2024 heart disease and stroke statistics: a report of US and global data from the American Heart Association. Circulation. 2024;149(8):e347-e913.
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.
4. Shoamanesh A, Mundl H, Smith EE, et al. Factor XIa inhibition with asundexian after acute non-cardioembolic ischaemic stroke (PACIFIC-Stroke): an international, randomised, double-blind, placebo-controlled, phase 2b trial. Lancet. 2022;400(10357):997-1007.