Study of Recombinant Coagulation Factor IX Fc Fusion Protein, BIIB029, in Previously Treated Pediatric Participants With Hemophilia B

Vials of rFIXFc were combined as needed, based on the actual labeled potency to achieve the participant's calculated dose. Partial vial use was allowed, in order to achieve the calculated dose.

Vials of prestudy FIX (provided by the participants) were combined as needed, based on the nominal labeled potency (e.g., 250 IU, 500 IU, and 1000 IU), to achieve the participant's calculated dose.