Study to evaLuate the effIcacy and Safety of abeLacimab in High-risk Patients With Atrial Fibrillation Who Have Been Deemed Unsuitable for Oral antiCoagulation (LILAC-TIMI 76)

Inclusion Criteria:

1. Patient is able to understand and willing to provide written informed consent to participate in the trial
2. Diagnosed Atrial Fibrillation (AF) or atrial flutter (documented on an electrocardiogram (ECG) or monitor recording)
3. Age 65-74 and a CHA2DS2VASc ≥5 OR age ≥75 and a CHA2DS2VASc ≥4
4. Judged by the responsible physician or by their own decision to be unsuitable for oral anticoagulation
5. At least 1 bleeding risk factor such as severe renal insufficiency, planned daily use of antiplatelet medication for the duration of the trial, history of bleeding from a critical area, or other conditions associated with increased risk of bleeding such as chronic nonsteroidal anti-inflammatory drug (NSAID) use, frailty or multiple falls

Exclusion Criteria:

1. AF due to an ongoing acute reversible cause (e.g., cardiac surgery, pulmonary embolism (PE), untreated hyperthyroidism, alcohol use)
2. Patients who received warfarin, dabigatran, rivaroxaban, apixaban, or edoxaban within 60 days prior to randomization
3. Patients with an intracranial or intraocular bleed within the 3 months prior to screening or any history of spontaneous intracerebral hemorrhage at any time in the absence of antithrombotic treatment
4. Any stroke within 14 days before randomization or transient ischemic attack (TIA) within 3 days before randomization
5. Mechanical heart valve or valve disease that is expected to require mechanical valve replacement intervention (surgical or invasive) during the course of the study

Other protocol defined Inclusion/Exclusion criteria may apply