Results of the ANNEXA-I trial show that treatment with andexanet alfa resulted in lower expansion of hematoma volume compared with usual care for patients with intracerebral hemorrhage who were receiving factor Xa inhibitors. For the study, 530 patients who had taken factor Xa inhibitors within 15 hours before having an acute intracerebral hemorrhage were randomized to receive andexanet or usual care. The most common indication for factor Xa inhibitors was atrial fibrillation. Hemostatic efficacy, the primary endpoint, was defined by three factors at 12 hours: expansion of hematoma by 35% or less, an increase of less than 7 points on the National Institutes of Health Stroke Scale, and no receipt of rescue therapy. This composite measure was achieved in 67.0% of the andexanet group and 53.1% of those receiving usual care. The median percent change from baseline to the 1-to-2-hour nadir in anti-factor Xa activity was 94.5% and 26.9%, respectively. Thrombotic events were more common in the andexanet group, at a rate of 10.3% vs. 5.6% in the usual care group, and ischemic stroke occurred in 6.5% and 1.5%, respectively. Between-group differences in scores on the modified Rankin scale or in death within 30 days did not differ appreciably.