FDA approves Sunharbo, first factor XIa inhibitor, for secondary stroke prevention

The FDA announced on November 09, 2026 that it had approved Sunharbo (asundexian) 50 mg tablets as the first factor XIa inhibitor to be used alongside antiplatelet therapy to lower stroke risk in adults who recently had a mild-to-moderate non-cardioembolic ischemic stroke or a high-risk transient ischemic attack.¹

Hylton V. Joffe, director of the FDA's Office of Cardiology, Hematology, Endocrinology, and Nephrology, said stroke remains a leading cause of disability and death in the United States, with survivors facing risk of recurrence, and called the approval a meaningful advance for secondary stroke prevention.¹

Efficacy data came from the phase 3 "OCEANIC-STROKE" trial, described as a multicenter, randomized, double-blind, placebo-controlled study that enrolled 12,327 adults.¹ Participants had a recent non-cardioembolic ischemic stroke with NIH Stroke Scale scores of 15 or less, or a high-risk TIA, and were randomized to Sunharbo or placebo within 72 hours of symptom onset while both arms also received antiplatelet therapy.¹ Over a median treatment period of 14.2 months, the once-daily 50 mg dose lowered ischemic stroke incidence by 26% relative to placebo.¹

On safety, overall major bleeding rates were comparable between the drug and placebo arms, though bleeding risk rose in patients over 75 and within the first 90 days of treatment, and gastrointestinal bleeding was more frequent with Sunharbo.¹ Diarrhea was the most common adverse reaction, reported in at least 3% of treated patients.¹

The label notes combined P-gp and strong CYP3A4 inducers such as carbamazepine are not recommended because they may reduce the drug's effectiveness,¹ and the drug is not recommended for patients with moderate or severe hepatic impairment, and dosing should pause at least 24 hours before elective surgery or invasive procedures, and for 24 hours following thrombolysis for acute ischemic stroke.¹

Sunharbo's approval does not extend to patients with atrial fibrillation, according to the FDA, which separately noted that the agency had granted the drug both Fast Track and Priority Review status before clearing it for Bayer HealthCare Pharmaceuticals Inc. of Whippany, New Jersey.