FDA Approves Asundexian, First FXIa Inhibitor to Prevent Repeat Stroke

Asundexian (Sunharbo; Bayer) was approved by the FDA on November 9, 2026, in combination with antiplatelet therapy, to reduce the risk of stroke in adults after a recent mild-to-moderate noncardioembolic ischemic stroke (National Institutes of Health Stroke Scale [NIHSS] score ≤ 15) or a high-risk transient ischemic attack (TIA).^1,3

Asundexian is the first factor XIa (FXIa) inhibitor approved by the FDA and is taken orally as a 50-mg dose once daily.¹ Earlier exploratory trials demonstrated its ability to directly inhibit FXIa without increasing the risk of bleeding. The approval was based on findings from the global OCEANIC-STROKE (NCT05686070) phase 3, multicenter, randomized, double-blind, placebo-controlled clinical trial. The final results were presented earlier this year at the 2026 International Stroke Conference in New Orleans, Louisiana.² Data showed a significant reduction in recurrent ischemic stroke with asundexian, with a consistent effect across subgroups, including stroke subtypes.²

“For those who survive a stroke, the risk of another potentially devastating event is highest in the days and weeks after the initial event, and that risk persists over time,” Ashkan Shoamanesh, MD, co-principal investigator of the OCEANIC-STROKE clinical study and senior scientist at Population Health Research Institute, a joint institute of Hamilton Health Sciences and McMaster University, in Ontario, Canada, said in a press release. “I believe asundexian introduces an important new addition to post-stroke care that can be used to help patients reduce the risk of a secondary stroke.”³

OCEANIC-STROKE Enrolled More Than 12,000 Patients With Recent Noncardioembolic Stroke or TIA

The trial enrolled 12,327 patients (mean age, 68 years; 33% female) who had experienced a recent mild-to-moderate noncardioembolic ischemic stroke or high-risk TIA between January 2023 and February 2025, with follow-up ranging from at least 3 months to up to 31 months. Patients were randomized within 72 hours of symptom onset to receive either 50 mg of asundexian daily (n = 6,162) or placebo (n = 6,165), in addition to antiplatelet therapy.^1,2

Participants were required to have at least 1 of the following: a history of atherosclerosis, imaging evidence of atherosclerosis in intracranial or extracranial vessels, or a visualized nonlacunar infarct.²

Ischemic stroke was the index event for 95% of participants, and 27% of index strokes were treated with intravenous thrombolysis and/or mechanical thrombectomy. Based on the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification, large artery atherosclerosis accounted for 43% of index strokes, small vessel occlusion for 22%, undetermined causes for 30%, and cardioembolic sources for 2%. More than half of patients were planned to receive dual antiplatelet therapy at randomization.²

Asundexian Cut Recurrent Ischemic Stroke Risk by 26% Without Raising Major Bleeding

The primary efficacy end point was time to ischemic stroke, and the primary safety end point was major bleeding based on International Society on Thrombosis and Haemostasis (ISTH) criteria.^2,3

Patients in the asundexian group experienced a lower risk of recurrent ischemic stroke than those in the placebo group (cause-specific HR [csHR], 0.74; 95% CI, 0.65-0.84; P < .001). There was no significant increase in the risk of ISTH major bleeding with asundexian compared with placebo (csHR, 1.10; 90% CI, 0.85-1.44; P = .46).²

Asundexian was also associated with lower rates across secondary end points, including ischemic or hemorrhagic stroke (csHR, 0.74; 95% CI, 0.65-0.84; P < .001); cardiovascular death, myocardial infarction, or stroke (csHR, 0.83; 95% CI, 0.74-0.92; P < .001); and all-cause mortality, myocardial infarction, or stroke (csHR, 0.85; 95% CI, 0.77-0.95; P = .003).²

According to the FDA, asundexian 50 mg once daily reduced the risk of ischemic stroke by 26% versus placebo over a median treatment duration of 14.2 months. Although overall major bleeding rates were similar between groups, major bleeding was higher with asundexian among patients older than 75 years and during the first 90 days of treatment, and gastrointestinal bleeding was more common with asundexian. Diarrhea was the most common adverse reaction. Asundexian is not approved for stroke prevention in patients with atrial fibrillation.¹

“Stroke is a leading cause of disability and death in the United States, and survivors are at risk of having another stroke,” Hylton V. Joffe, MD, MMSc, director of the Office of Cardiology, Hematology, Endocrinology, and Nephrology in the FDA’s Center for Drug Evaluation and Research, said in a press release. “Today’s approval represents a meaningful advance for patients and health care providers seeking a new option for secondary stroke prevention.”¹

References

1. FDA approves first factor Xla inhibitor to help prevent stroke in certain adults at high risk. FDA. November 9, 2026. Accessed November 10, 2026. https://www.fda.gov/news-events/press-announcements/fda-approves-first-factor-xla-inhibitor-help-prevent-stroke-certain-adults-high-risk

2. McNulty R. Asundexian reduces risk of stroke recurrence in phase 3 OCEANIC-STROKE trial. AJMC. February 13, 2026. Accessed November 10, 2026. https://www.ajmc.com/view/asundexian-reduces-risk-of-stroke-recurrence-in-phase-3-oceanic-stroke-trial

3. Bayer’s asundexian first FXIa inhibitor approved by U.S. Food and Drug Administration for secondary stroke risk reduction. Bayer. November 10, 2026. Accessed November 10, 2026. https://www.bayer.com/media/en-us/bayers-asundexian-first-fxia-inhibitor-approved-by-us-food-and-drug-administration-for-secondary-stroke-risk-reduction/