A new anti-clotting approach wins US approval after a 26% relative reduction in repeat ischemic strokes

Preventing harmful clots while preserving normal bleeding control is a longstanding challenge. On November 9, the FDA approved Sunharbo, or asundexian, the first US-approved factor XIa inhibitor.

A randomized, double-blind trial enrolled 12,327 people. Both groups received antiplatelet therapy, plus either the drug or placebo. Ischemic stroke risk fell 26% relatively, with similar overall major-bleeding rates.

The drug targets a different step in clotting, seeking a better balance between clot prevention and normal hemostasis. Reuters covered the approval, which adds an option for some stroke survivors.

It is for certain adults after recent mild-to-moderate noncardioembolic ischemic stroke or high-risk TIA, alongside antiplatelet therapy. FDA warnings include increased major bleeding above age 75 and during the first 90 days, plus more gastrointestinal bleeding. It is not approved for stroke prevention in atrial fibrillation. Eligibility requires medical assessment.

Source times: Reuters, November 10, 2026, 06:27:15 Beijing / November 9, 5:27:15 PM EST; Bayer announcement, November 10, 07:15 Beijing / November 9, 6:15 PM EST.