Pharmacokinetics and Safety of rFVIIIFc Manufactured at 15,000 L (15K) Scale

PK assessments are in 3 phases: Pharmacokinetic Assessment 1(PK1): PK assessments following
single injection of rFVIIIFc manufactured at the 2K scale. Pharmacokinetic Assessment 2
(PK2): PK assessments are made following a single injection of rFVIIIFc manufactured at the
15K scale where participants are randomized to the 1000 IU vial or 6000 IU/vial strengths.
Pharmacokinetic Assessment 3 (PK3): PK assessments are made following 13 weeks of rFVIIIFc
treatment manufactured at the 15K scale where participants are randomized to the 1000 IU vial
or 6000 IU/vial strengths. After study completion, in countries where rFVIIIFc is not
commercially available, eligible participants will be offered enrollment into a long-term
safety and efficacy extension study (8HA01EXT [NCT01454739]).

Key Inclusion Criteria:

- Have severe hemophilia A, defined as <1 IU/dL (<1%) endogenous FVIII as determined by
one-stage clotting assay from the central laboratory at Screening.

- Previously treated subject, defined as having at least 150 documented prior exposure
days (EDs) to any recombinant and/or plasma-derived FVIII and/or cryoprecipitate
products at Day 1. Fresh frozen plasma treatment must not be considered in the count
for documented exposure days.

- No history of a positive inhibitor test or clinical signs of decreased response to
FVIII administrations. Family history of inhibitors will not exclude the subject.

- No measurable inhibitor activity using the Nijmegen-modified Bethesda assay (>=0.6
Bethesda Unit per milliliter [BU/mL] is considered positive) at Screening.

Key Exclusion Criteria:

- Current enrollment in any interventional clinical study in which an investigational
drug or approved therapy for investigational use is administered within 30 days prior
to the Baseline Visit OR prior participation in any of the following Biogen studies:
998HA101 (NCT01027377), 997HA301 (NCT01181128), 8HA02PED (NCT01458106), 997HA307
(NCT02083965), and 8HA01EXT (NCT01454739).

- Previous participation in this study.

- Any concurrent clinically significant major disease that, in the opinion of the
Investigator or Biogen, makes the subject unsuitable for participation in the study.

- Other coagulation disorder(s) in addition to hemophilia A.

- History of hypersensitivity or anaphylaxis associated with FVIII or intravenous (IV)
immunoglobulin administration.

NOTE: Other protocol-defined inclusion/exclusion criteria may apply.