The objectives of this study are to assess the tolerability and safety after single dose treatments of BAX 855 in previously treated patients (PTPs) with severe hemophilia A, to determine the pharmacokinetic (PK) parameters of BAX 855 compared in crossover with ADVATE, and to evaluate the impact of anti-polyethylene glycol (PEG) antibodies on PK parameters.

Inclusion Criteria:

• The subject is male and is 18 to 65 years of age at the time of screening
• The subject has severe hemophilia A (factor VIII level < 1%)
• The subject was previously treated with plasma-derived factor VIII (FVIII) concentrates or recombinant FVIII for at least 150 exposure days (EDs)

Exclusion Criteria:

• The subject has a detectable FVIII inhibitor at screening, with a titer >= 0.6 BU
• The subject has a documented history of FVIII inhibitors with a titer >= 0.4 BU at any time prior to screening
• The subject has a known hypersensitivity towards mouse or hamster proteins or to polyethylene glycol (PEG)