Bayer’s asundexian (Sunharbo) won FDA approval to reduce the risk of recurrent stroke in adults who recently had a mild-to-moderate non-cardioembolic ischemic stroke or a high-risk transient ischemic attack. The trial data showed a 26% relative reduction in the most common ischemic stroke outcome versus placebo, with major bleeding rates reported as similar across arms. The approval positions Sunharbo as the first therapy in a new class built around Factor XIa inhibition, aiming to prevent harmful clot formation while avoiding the bleeding liabilities seen with some older blood thinners. In the study, gastrointestinal side effects—especially diarrhea—were among the most frequently reported adverse reactions. Clinically, the differentiator for adoption will likely be access and sequencing alongside established antiplatelet therapy, given that Sunharbo is cleared for use in combination with standard care rather than as a standalone replacement.