The document describes a clinical trial comparing the factor Xa inhibitor edoxaban to warfarin for preventing thromboembolic events in patients with atrial fibrillation. Over 21,000 patients were randomly assigned to receive either high-dose or low-dose edoxaban once daily or dose-adjusted warfarin. The primary endpoint of stroke or systemic embolism occurred less frequently with high-dose edoxaban compared to warfarin. Both edoxaban doses resulted in lower rates of bleeding events compared to warfarin. The trial demonstrated that edoxaban was non-inferior and potentially superior to warfarin in preventing thromboembolic events while causing fewer bleedings in patients with at