FDA has granted marketing authorization for asundexian, 50 mg tablets, to be sold under the brand name Sunharbo, making it the first approved Factor XIa inhibitor worldwide.

The product is indicated for use in combination with antiplatelet therapy to reduce the risk of stroke in adults with a recent non-cardioembolic ischemic stroke (National Institutes of Health Stroke Scale ≤15) or high-risk transient ischemic attack (TIA).¹ This use is often referred to as secondary stroke prevention, reflecting the goal of reducing the risk of another stroke after an initial event.

The approval addresses a period that clinicians consider dangerous for stroke survivors, as the risk of a second potentially devastating event is highest in the days and weeks immediately following an initial stroke, and that elevated risk persists over time.¹ Stroke remains a significant global health burden, affecting approximately 12 million people worldwide each year, including 795,000 individuals in the U.S., and is the second leading cause of death and the third leading cause of death and disability combined worldwide.¹

Christian Rommel, Ph.D., global head of research and development at Bayer’s Pharmaceuticals Division, calls the approval a milestone built on the completed Oceanic-stroke study. “This FDA approval represents a bold step forward in post-stroke care and is based on compelling clinical evidence from our successfully completed Oceanic-stroke study. Asundexian is the first drug approved in a new class of Factor XIa inhibitors worldwide,” Rommel says. “Stroke requires substantial healthcare resource utilization and presents a significant economic and personal burden. At Bayer, our priority is advancing innovations like asundexian to help close gaps in care and reduce the burden of secondary stroke.”

What clinical evidence supported the approval?

FDA’s approval is based on positive data from the pivotal, global Phase III Oceanic-stroke study, described as the first successfully completed Phase III study of a Factor XIa inhibitor used in combination with antiplatelet therapy.² The study demonstrated superiority in reducing ischemic stroke compared to antiplatelet therapy alone (dual or single antiplatelet therapy), with a similar rate of major bleeding, as classified by the International Society on Thrombosis and Hemostasis (ISTH), between asundexian and placebo.²

Asundexian 50 mg in combination with antiplatelet therapy significantly reduced ischemic stroke by 26% in patients after a non-cardioembolic ischemic stroke or high-risk TIA, compared to antiplatelet therapy alone. The reduction was observed alongside a similar rate of ISTH-classified bleeding between asundexian and placebo. The treatment effect for the primary endpoint remained consistent across key subgroups, including age, sex, type of index event, non-cardioembolic stroke subtypes, stroke severity, and planned antiplatelet therapy, supporting the drug’s potential use across a broad patient population.²

Full results from Oceanic-stroke have been published in The New England Journal of Medicine.

Why does this mechanism matter for stroke prevention?

Factor XIa is a protein in the blood coagulation pathway that plays differing roles in hemostasis and thrombosis, and is thought to contribute to pathological thrombus growth and vessel blockage, but plays only a minor role in forming the hemostatic plug that seals a vessel injury.¹ Asundexian selectively inhibits Factor XIa, which allows it to reduce pathological clot formation while maintaining a similar rate of ISTH major bleeding compared to placebo, effectively uncoupling hemostasis from pathological thrombosis.

Ashkan Shoamanesh, M.D., 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, Ontario, Canada, says the risk of a second stroke is highest in the days and weeks after an initial event and persists over time. “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,” Shoamanesh said.

What comes next for asundexian beyond the U.S.?

Alongside its FDA approval, Asundexian was also recently approved by China’s National Medical Products Administration (NMPA), with Bayer also submitting the drug for marketing authorization in additional markets around the world, with those applications currently under review.¹

Bayer says it expects to continue working with health authorities worldwide as it seeks to bring asundexian to patients in other regions, positioning the drug as the first in a new treatment class to reach the global secondary stroke prevention market.¹

Sources

1. Bayer’s asundexian first FXIa inhibitor approved by U.S. Food and Drug Administration for secondary stroke risk reduction Bayer 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/ 
2. 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) National Library of Medicine November 12, 2025, https://clinicaltrials.gov/study/NCT05686070