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.

Inclusion Criteria:

• 21 years of age or older; male or female.
• Able to provide written informed consent.
• History of documented AF within the prior 12 months
• A moderate to high risk of stroke, as defined by CHADS2 index score of at least 2

Exclusion Criteria:

• Transient atrial fibrillation secondary to other reversible disorders

• Subjects with moderate or severe mitral stenosis, unresected atrial myxoma, or a mechanical heart valve

• Subjects with any contraindication for anticoagulant agents;

• Subjects with conditions associated with high risk of bleeding or have known or suspected hereditary or acquired bleeding disorders

• Females of childbearing potential including the following:

  • Females with a history of tubal-ligation
  • Females less than 2 years post-menopausal

De-identified individual participant data (IPD) and applicable supporting clinical trial documents may be available upon request at https://vivli.org/. In cases where clinical trial data and supporting documents are provided pursuant to our company policies and procedures, Daiichi Sankyo will continue to protect the privacy of our clinical trial participants. Details on data sharing criteria and the procedure for requesting access can be found at this web address: https://vivli.org/ourmember/daiichi-sankyo/

Studies for which the medicine and indication have received European Union (EU) and United States (US), and/or Japan (JP) marketing approval on or after 01 January 2014 or by the US or EU or JP Health Authorities when regulatory submissions in all regions are not planned and after the primary study results have been accepted for publication.

Formal request from qualified scientific and medical researchers on IPD and clinical study documents from clinical trials supporting products submitted and licensed in the United States, the European Union and/or Japan from 01 January 2014 and beyond for the purpose of conducting legitimate research. This must be consistent with the principle of safeguarding study participants' privacy and consistent with provision of informed consent.