See related article, p 1608. In the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibitor Compared With Vitamin K Antagonism for Prevention of

AF) trial, the efficacy and safety of rivaroxaban, a novel, oral, direct factor Xa inhibitor, was assessed for the prevention of stroke in patients with atrial fibrillation (AF) and at moder-ate to high risk of stroke.1 Results from this study showed that rivaroxaban (20 mg once daily or 15 mg once daily in patients with a creatinine clearance [CrCl] of 30–49 mL/min) was non-inferior to dose-adjusted warfarin for the prevention of stroke and systemic embolism in an intention-to-treat (ITT) analysis. Rates of major or nonmajor clinically relevant bleeding were Background and Purpose—In Rivaroxaban Once Daily Oral Direct Factor Xa Inhibitor Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF) trial, rivaroxaban was noninferior to dose-adjusted warfarin in preventing stroke or systemic embolism among patients with nonvalvular atrial fibrillation at moderate to high stroke risk. Because of differences in patient demographics, epidemiology, and stroke risk management in East Asia, outcomes and relative effects of rivaroxaban versus warfarin were assessed to determine consistency among East Asians versus other ROCKET AF participants