An Open Label Study to Determine the Safety and Efficacy of Replacement Factor VIII Protein (Known as rFVIIIFc) in Previously Untreated Males With Severe Hemophilia A

An Open-Label, Multicenter Evaluation of the Safety and Efficacy of Recombinant Coagulation Factor VIII Fc Fusion Protein (rFVIIIFc; BIIB031) in the Prevention and Treatment of Bleeding in Previously Untreated Patients With Severe Hemophilia A

The primary objective of the study was to evaluate the safety of rFVIIIFc (BIIB031) in previously untreated participants (PUPs) with severe hemophilia A. The secondary objectives were to evaluate the efficacy of rFVIIIFc in the prevention and treatment of bleeding episodes in PUPs, to evaluate rFVIIIFc consumption for the prevention and treatment of bleeding episodes in PUPs, and to describe experience with the use of rFVIIIFc for immune tolerance induction (ITI) in participants with inhibitors.

Key Inclusion Criteria:

• Ability of the participant's legally authorized representative (e.g. their parent or legal guardian) to understand the purpose and risks of the study and provide signed and dated informed consent and authorization to use confidential health information in accordance with national and local participant privacy regulations.
• Weight >=3.5 kg at the time of screening.
• Severe hemophilia A defined as less than (<) 1 IU/dL (<1%) endogenous FVIII documented in the medical record or as tested during the Screening Period.

Key Exclusion Criteria:

• Any exposure to blood components, factor VIII replacement products, including commercially available rFVIIIFc at any time prior to or during screening.
• History of positive inhibitor testing. A prior history of inhibitors was defined based on a patient's historical positive inhibitor test using the local laboratory Bethesda value for a positive inhibitor test (ie, equal to or above lower level of detection).
• History of hypersensitivity reactions associated with any rFVIIIFc administration.
• Other coagulation disorder(s) in addition to hemophilia A.
• Any concurrent clinically significant major disease that, in the opinion of the Investigator, would make the participant unsuitable for enrollment.
• Current systemic treatment with chemotherapy and/or other immunosuppressant drugs.

Note: Other protocol defined Inclusion/Exclusion criteria may apply.