A Phase 3, Randomized, Double-Blind, Double-Dummy, Parallel Group, Multi-Center, Multi-National Study for Evaluation of Efficacy and Safety of Edoxaban (DU-176b) Versus Warfarin In Subjects With Atrial Fibrillation - Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation (ENGAGE - AF TIMI - 48)

This study is to demonstrate the safety and efficacy profile, in two different dose regimens of Edoxaban (DU-176b), (an investigational new drug being tested for the prevention of stroke/systemic embolic events (SEE)), in individuals with atrial fibrillation. Patients will be randomized to one of three treatment groups: High Dose Regimen, Low Dose Regimen, \& Warfarin. The expected duration of the study is 24 months.