BAX 855 Pediatric Study

The study purpose is:

* To assess the incidence of FVIII inhibitory antibodies during 6 months of twice weekly prophylactic treatment with BAX 855 or 50 exposure days (EDs), whichever occurs last.
* To compare pharmacokinetic (PK) parameters to ADVATE.
* To assess hemostatic efficacy in prophylaxis and the treatment of bleeding episodes.
* To evaluate safety and immunogenicity.


Eligibility Criteria:
Inclusion Criteria:

* Severe hemophilia A (Factor VIII (FVIII) \<1%) determined by central laboratory.
* \<12 years old at the time of screening.
* Participants aged ≥6 to \<12 years of age have been previously treated with plasma-derived and/or recombinant Factor VIII (rFVIII) concentrate(s) for a minimum of 150 exposure days (EDs) (based on the participant's medical records).
* Participants \<6 years of age have been previously treated with plasma-derived and/or rFVIII concentrate(s) for at least 50 EDs (based on the participant's medical records).
* Participant is human immunodeficiency virus (HIV) negative; or HIV positive with stable disease and CD4+ count of ≥200 cells/mm\^3, as confirmed by central laboratory.
* Participant and/or legal representative accepts prophylactic treatment over a period of 6 months.
* Participant and/or the legal representative is willing and able to comply with the requirements of the protocol.

Exclusion Criteria:

* Participant has detectable FVIII inhibitory antibodies (≥0.4 Bethesda Units (BU) using the Nijmegen modification of the Bethesda assay) as confirmed by central laboratory at screening.
* Participant has a history of FVIII inhibitory antibodies (≥0.4 BU using the Nijmegen modification of the Bethesda assay or ≥0.6 BU using the Bethesda assay) at any time prior to screening.
* Participant has known hypersensitivity towards mouse or hamster proteins, polyethylene glycol (PEG), or Tween 80.
* Participant has been diagnosed with an inherited or acquired hemostatic defect other than hemophilia A (eg, qualitative platelet defect or von Willebrand's disease).
* Participant's platelet count is \<100,000/μL.
* Participant has severe chronic hepatic dysfunction (eg, ≥5 times upper limit of normal (ULN) alanine aminotransferase (ALT), as confirmed by central laboratory at screening, or a documented international normalized ratio (INR) \>1.5).
* Participant has severe renal impairment (serum creatinine \>1.5 times ULN).
* Participant is scheduled to receive during the course of the study, an immunomodulating drug (eg, corticosteroid agents at a dose equivalent to hydrocortisone \>10 mg/day, or α-interferon) other than anti-retroviral chemotherapy.
* Participant has current or recent (\<30 days) use of other PEGylated drugs prior to study participation or is scheduled to use such drugs during study participation.
* Participant has participated in another clinical study involving an investigational product (IP) or investigational device within 30 days prior to enrollment or is scheduled to participate in another clinical study involving an IP or investigational device during the course of this study.
* Participant has a medical, psychiatric, or cognitive illness or recreational drug/alcohol use that, in the opinion of the Investigator, would affect participant safety or compliance.
* Participant's legal representative is a member of the team conducting this study or is in a dependent relationship with one of the study team members. Dependent relationships include close relatives (ie, children, partner/spouse, siblings, parents) as well as employees of the investigator or site personnel conducting the study.