A Study in Participants With Acute Major Bleeding to Evaluate the Ability of Andexanet Alfa to Reverse the Anticoagulation Effect of Direct and Indirect Oral Anticoagulants (Extension Study)

Key Inclusion Criteria:

• Acute major bleeding episode that required urgent reversal of anticoagulation; defined by at least one of the following:

• Acute bleeding that was potentially life-threatening, or
• Acute bleeding associated with a fall in hemoglobin level by ≥2 grams/deciliter (g/dL), or
• Acute bleeding associated with a hemoglobin level of ≤8 g/dL if no baseline hemoglobin was available, or
• Acute bleeding in a critical area or organ such as intraspinal, pericardial, or intracranial.
• If bleeding was intracranial or intraspinal, the participant must have undergone a head computed tomography (CT) or magnetic resonance imaging (MRI) scan demonstrating the bleeding.
• Participant received or was believed to have received one of the following within 18 hours prior to andexanet administration: apixaban, rivaroxaban, edoxaban, or enoxaparin.
• For participants with intracranial bleeding, there must be a reasonable expectation that andexanet treatment will commence within 2 hours of the baseline imaging evaluation.

Key Exclusion Criteria:

• The participant was scheduled to undergo surgery in less than 12 hours, with the exception of minimally invasive surgery/procedures.
• Participant with an intracerebral hemorrhage that had any of the following:

• Glasgow coma score <7, or
• Intracerebral hematoma >60 cubic centimeters as assessed by CT or MRI
• Participants with visible, musculoskeletal or intra-articular bleeding as their qualifying bleed.
• Expected survival of less than 1 month.
• Recent history (within 2 weeks) of a diagnosed thrombotic event as follows: venous thromboembolism, myocardial infarction, disseminated intravascular coagulation, cerebral vascular accident, transient ischemic attack, unstable angina pectoris hospitalization or severe peripheral vascular disease within 2 weeks prior to Screening.
• Severe sepsis or septic shock at the time of Screening.
• Pregnant or a lactating female.
• Participant received any of the following drugs or blood products within 7 days of Screening:

• Vitamin K antagonist
• Dabigatran
• Prothrombin Complex Concentrate (PCC) products or recombinant factor VIIa (rfVIIa)
• Whole blood, plasma fractions
• Treated with an investigational drug <30 days prior to Screening.
• Planned administration of PCC, fresh frozen plasma or rfVIIa from Screening until within 12 hours after the end of the andexanet infusion.