FDA approves Bayer's Sunharbo as first factor XIa inhibitor for secondary stroke prevention

Bayer's first-in-class factor XIa inhibitor has secured FDA approval for secondary stroke prevention, offering a new antithrombotic approach alongside antiplatelet therapy for selected high-risk adults.

The US Food and Drug Administration approved Bayer's Sunharbo (asundexian) 50 mg tablets on 9 November 2026 for use with antiplatelet therapy to reduce stroke risk in adults following a recent mild-to-moderate non-cardioembolic ischaemic stroke or high-risk transient ischaemic attack, making it the first FDA-approved factor XIa inhibitor.

The decision was supported by the Phase III OCEANIC-STROKE trial, which demonstrated a 26% relative reduction in ischaemic stroke compared with antiplatelet therapy alone and similar overall rates of ISTH major bleeding, establishing a new treatment option for a specifically defined secondary-prevention population rather than general stroke prevention.

Field	Content
Article Type	Approvals
Company	Bayer
Product	Sunharbo
Active Ingredient	Asundexian
Regulatory Authority	US Food and Drug Administration
Approval Date	9 November 2026
Approval Type	FDA marketing approval
Regulatory Status	Approved in the United States for the specified secondary stroke prevention indication
First-in-Class Status	First FDA-approved factor XIa inhibitor
Therapeutic Area	Cardiovascular and cerebrovascular medicine
Treatment Objective	Secondary stroke prevention
Approved Indication	Reduce stroke risk in adults following recent mild-to-moderate non-cardioembolic ischaemic stroke or high-risk transient ischaemic attack
Eligible Population	Adults meeting the specified recent stroke or high-risk transient ischaemic attack criteria
Stroke Subtype	Non-cardioembolic ischaemic stroke
Additional Eligible Condition	High-risk transient ischaemic attack
Dosage Form	Oral tablets
Approved Strength	50 mg
Combination Treatment	Antiplatelet therapy
Drug Class	Factor XIa inhibitor
Molecular Target	Activated coagulation factor XI
Mechanism of Action	Inhibition of factor XIa within the coagulation pathway
Supporting Clinical Trial	OCEANIC-STROKE
Clinical Trial Phase	Phase III
Comparator	Antiplatelet therapy alone
Reported Efficacy Result	26% relative reduction in ischaemic stroke
Bleeding Safety Finding	Similar overall rates of ISTH major bleeding between treatment groups
Bleeding Definition	International Society on Thrombosis and Haemostasis major bleeding
Absolute Risk Reduction	Not specified in supplied summary
Trial Population Size	Not specified in supplied summary
What Happened	The FDA approved Sunharbo as the first factor XIa inhibitor for secondary stroke prevention in a defined adult population.
Why It Matters	The approval introduces a new anticoagulant mechanism to complement antiplatelet therapy for selected patients at risk of recurrent stroke.
Clinical Significance	Phase III evidence demonstrated a relative reduction in ischaemic stroke without an apparent increase in overall ISTH major bleeding rates.
Regulatory Clarification	The approval applies to the specified secondary-prevention population and combination regimen rather than general stroke prevention.
Key Takeaway	Sunharbo establishes factor XIa inhibition as an FDA-approved therapeutic approach for selected adults following non-cardioembolic stroke or high-risk TIA.
What to Watch	Clinical adoption, prescribing guidance, bleeding safety surveillance, reimbursement and additional factor XIa inhibitor development.
Primary Source	US Food and Drug Administration
Primary Source URL	https://www.fda.gov/news-events/press-announcements/fda-approves-first-factor-xla-inhibitor-help-prevent-stroke-certain-adults-high-risk
Relevant Date	9 November 2026

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