Efficacy and Safety of MAA868 in Patients With Atrial Fibrillation

Inclusion Criteria: * Male and female patients ≥ 55 and \< 85 years old * Body weight between 50 and 130 kg inclusive * Atrial fibrillation or atrial flutter, as documented by electrocardiography * CHA2DS2-VASc risk score ≥ 2 for male and female patients. Male patients with CHA2DS2VASc risk score of 1 can be included if anticoagulation therapy is warranted. * Either anticoagulant-naïve or receiving a stable treatment of a recommended dose of a new oral anticoagulant (NOAC) over the 8 weeks prior to screening. Exclusion Criteria: * History of stroke, transient ischemic attack or systemic embolism * History of major bleeding during treatment with an anticoagulant or antiplatelet therapy in the last 12 months * History of traumatic or non-traumatic intracranial, intraspinal or intra-ocular bleeding * Known bleeding diathesis or any known active bleeding site at screening or baseline * Family history of bleeding disorder * Known active GI lesions predisposing to bleeding events * Myocardial infarction, unstable angina pectoris or coronary artery bypass graft (CABG) surgery within 12 months prior to the screening period * Known hemodynamically significant valvular heart disease * Uncontrolled hypertension defined as SBP/DBP ≥ 160/100 mmHg at the screening visit * Heart failure NYHA class IV in the 3 months prior to the screening visit * Dual antiplatelet therapy. Treatment with a P2Y12 inhibitor or low dose aspirin (≤ 100 mg/d) is allowed but not both. * Severe renal impairment (creatinine clearance \< 30 mL/min) at the screening visit