Asundexian reduced relative ischemic stroke risk by 26% alongside antiplatelet therapy, with bleeding concerns in older adults.
Asundexian (Sunharbo) has received FDA approval as an addition to antiplatelet therapy to reduce stroke risk in adults after a recent mild-to-moderate noncardioembolic ischemic stroke or high-risk transient ischemic attack (TIA). The November 9, 2026, decision makes the 50-mg tablet the first approved factor XIa inhibitor, according to the agency.¹
The approval provides an additional secondary prevention option for this defined population—not for patients with atrial fibrillation. In the pivotal OCEANIC-STROKE trial, asundexian reduced the relative risk of ischemic stroke by 26% compared with placebo when both were added to antiplatelet therapy.¹
“Stroke is a leading cause of disability and death in the United States, and survivors are at risk of having another stroke,” said 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.¹
OCEANIC-STROKE was a multicenter, randomized, double-blind, placebo-controlled phase 3 trial enrolling 12,327 adults. Eligible participants had a recent noncardioembolic ischemic stroke with a National Institutes of Health Stroke Scale score of 15 or less, or a high-risk TIA. Randomization occurred within 72 hours of symptom onset.¹
Participants received asundexian 50 mg once daily or placebo, alongside antiplatelet therapy. Over a median treatment duration of 14.2 months, asundexian significantly reduced ischemic stroke risk, the FDA reported. The announcement did not provide absolute event rates, confidence intervals, or a number needed to treat, limiting assessment of the absolute benefit from the reported relative reduction.¹
The comparison establishes efficacy for adding asundexian to antiplatelet therapy in the studied population. It does not establish that asundexian should replace antiplatelet treatment or that the findings apply to stroke prevention in atrial fibrillation, an indication specifically excluded from the approval.¹
“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, Ontario, Canada, said in a Bayer 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.”2
Overall major bleeding rates were similar between treatment groups, but the FDA reported increased major bleeding with asundexian among patients older than 75 years and during the first 90 days of treatment. Gastrointestinal bleeding also occurred more frequently with asundexian. Diarrhea was the most frequently reported adverse reaction, occurring in at least 3% of treated patients.¹
These findings warrant attention to the timing and distribution of bleeding events rather than interpreting the overall comparison as evidence of equivalent safety for every patient. The announcement did not quantify the excess bleeding risk in older adults or during early treatment.¹
The FDA advises against concomitant use with medicines that are combined P-glycoprotein and strong CYP3A4 inducers, such as carbamazepine, because they may reduce asundexian’s effectiveness. Treatment is also not recommended in patients with moderate or severe hepatic impairment.¹
Asundexian should be withheld for at least 24 hours before elective surgery or invasive procedures and for at least 24 hours after thrombolysis for acute ischemic stroke, according to the agency.¹
Asundexian targets activated coagulation factor XI. Its approved role is adjunctive secondary prevention after the specified noncardioembolic events, with antiplatelet therapy remaining part of the regimen. The trial’s early enrollment window and stroke-severity criteria are important when considering how closely an individual patient resembles the study population.¹
The FDA granted Fast Track and Priority Review designations and awarded approval to Bayer HealthCare Pharmaceuticals Inc. Absolute efficacy results and more detailed bleeding analyses would help clinicians assess the benefit-risk balance, particularly in patients older than 75 years.¹
