A Phase 2, Randomized, Parallel Group, Multi-Center, Multi-National Study for the Evaluation of Safety and Efficacy of Two Fixed Dosages of DU-176b in Subjects With Non-Valvular Atrial Fibrillation

This study will be conducted in male and female subjects aged 18 to 80 years, inclusive, with non-valvular AF and a CHADS2 Score of at least 1. Subjects will be treated on an outpatient basis. The subjects will be allocated randomly to the open-label warfarin or any double-blind DU-176b dosages. DU-176b will be administered orally for 12 weeks at two fixed doses. Warfarin will be used as active control. Warfarin dosing will be managed and monitored by the Investigator with the dose adjusted to achieve an INR of 2.0 to 3.0, inclusive. The primary endpoints are incidence of major, clinically relevant non-major and minor bleeding events (all bleeding).