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FDA approves the factor XIa inhibitor asundexian for secondary stroke prevention

On November 09, 2026, the U.S. Food and Drug Administration (FDA) approved asundexian, a factor XIa (FXIa) inhibitor, in combination with antiplatelet therapy, for secondary stroke prevention in patients with non-cardioembolic ischemic stroke or high-risk transient ischemic attack (TIA). The approval was supported by data from the Phase III OCEANIC-STROKE trial (NCT05686070), in which asundexian significantly reduced the risk of recurrent ischemic stroke and major cardiovascular events compared with placebo, without increasing the risk of major bleeding.1,2

Unmet need in secondary stroke prevention

Approximately 12 million people worldwide have a stroke each year, and 20–30% of these strokes are recurrent events. Stroke is the second leading cause of death globally, with recurrent ischemic strokes carrying a higher mortality risk than the first stroke.3,4 Despite current secondary prevention options, up to one in five stroke survivors will have another stroke within five years, making the prevention of recurrence a central goal of care.3,4

Asundexian is a direct inhibitor of FXIa, a protein in the coagulation pathway that contributes to pathological thrombus growth and vessel occlusion. By inhibiting FXIa, asundexian is designed to reduce the thrombus formation that can narrow or block vessels and lead to ischemic stroke, without significantly increasing major bleeding.3

Pivotal data: the Phase III OCEANIC-STROKE trial

The approval was supported by results from OCEANIC-STROKE, a Phase III, double-blind, randomized, placebo-controlled trial evaluating asundexian in patients with non-cardioembolic ischemic stroke or high-risk TIA receiving standard single or dual antiplatelet therapy.2

The trial enrolled 12,327 patients within 72 hours of the onset of non-cardioembolic ischemic stroke or high-risk TIA. Participants had at least one of the following: a nonlacunar infarct on imaging, a history of atherosclerosis, or evidence of atherosclerotic plaque on cerebrovascular imaging. Patients were randomized to asundexian 50 mg once daily (n=6,162) or placebo (n=6,165), in addition to planned single or dual antiplatelet therapy, and were followed for a median of 19 months. The primary efficacy endpoint was ischemic stroke, and the primary safety endpoint was International Society on Thrombosis and Haemostasis (ISTH) major bleeding.2

The trial met its primary efficacy endpoint, with ischemic stroke occurring in 6.2% of patients in the asundexian group compared with 8.4% in the placebo group, a 26% relative reduction in the hazard of ischemic stroke (cause-specific hazard ratio [csHR] 0.74; 95% CI 0.65–0.84; p<0.001).2,4 Asundexian also reduced the incidence of the key secondary composite endpoint of cardiovascular death, myocardial infarction, or stroke.2

In an interview at the 2026 International Stroke Congress (ISC), Ashkan Shoamanesh, MD, FRCPC, McMaster University, Hamilton, Canada, discussed a pre-specified secondary analysis by qualifying ischemic stroke subtype: “What we found was that actually there is consistency across all ischemic stroke subtypes… And there was no heterogeneity in the treatment effect.”

Asundexian did not significantly increase the risk of ISTH major bleeding compared with placebo (1.9% vs 1.7%, respectively; csHR 1.10; 95% CI 0.85–1.44).2 Rates of minor bleeding, hemorrhagic stroke, symptomatic intracranial hemorrhage and fatal bleeding were also similar between the two groups.4 The incidence of adverse events (AEs) was similar in the asundexian and placebo groups (69.3% vs 70.1%, respectively), as was the incidence of serious AEs (19.2% vs 19.5%).2

Clinical implications

In a recent interview at the 18th World Stroke Congress (WSC), Mike Sharma, MD, MSc, FRCPC, McMaster University, Hamilton, Canada, shared his vision for the future of secondary stroke prevention: “Our goal with secondary stroke prevention is to bring the risk of another stroke as close to zero as possible. And I think this is a big advance.…. My hope is in five years we’ll have many patients on asundexian. We’ll have lower rates of recurrent stroke, lower cost to human beings, lower cost to the healthcare system and society, and get toward our goal of a zero chance of recurrence.”

The approval of asundexian introduces a new antithrombotic approach to secondary stroke prevention. By reducing the risk of recurrent ischemic stroke when added to standard antiplatelet therapy, without increasing major bleeding, asundexian gives clinicians an additional option for patients with non-cardioembolic ischemic stroke or high-risk TIA.

Written by Sophie Rea

Reviewed by Hannah Elkheir

References

  1. U.S FDA. FDA Approves First Factor Xla Inhibitor to Help Prevent Stroke in Certain Adults at High Risk. Available here. (Last accessed: 10/11/2026).
  2. Sharma M, Dong Q, Hirano T, et al. Asundexian for secondary stroke prevention. N Engl J Med 2026;394(15):1467–1479.
  3. Bayer. Bayer’s Asundexian Met Primary Efficacy and Safety Endpoints in Landmark Phase III OCEANIC-STROKE Study in Secondary Stroke Prevention. Available here. (Last accessed: 10/11/2026).
  4. Bayer. Bayer’s asundexian demonstrated a significant reduction in ischaemic stroke after a non-cardioembolic ischaemic stroke or high-risk transient ischaemic attack, with no increase in ISTH major bleeding versus placebo both in combination with antiplatelet therapy. Available here. (Last accessed: 10/11/2026).