Phase III study, to evaluate the efficacy and safety of continuous infusion of rFVIII-FS in the treatment of patients with hemophilia A undergoing major elective surgery by achieving the required therapeutic concentrations.

Inclusion Criteria:

• Severe hemophilia A (FVIII:C </=1%)
• No history of FVIII inhibitor formation and no current evidence of inhibitor antibody (Bethesda Assay < 0.6 BU)
• Elective major surgery requiring at least 6 days of rFVIII-FS therapy
• Subjects should have been previously treated with FVIII concentrates for at least 150 exposure days. Previous treatment could have been with any type of rFVIII or with plasma-derived FVIII concentrate or cryoprecipitate

Exclusion Criteria:

• Abnormal renal function (serum creatinine >1.3 mg/dL)
• Any treatments, which may change the clearance of FVIII (dialysis, plasma exchange)
• Anemia (hemoglobin <11 g/dL)
• Known AIDS (HIV seropositive patients may be enrolled)
• Active liver disease (transaminases > 5 times the upper limit of normal)
• History of severe reaction to FVIII concentrates
• Interferon treatment within the last 3 months
• Thrombocytopenia (< 100,000 platelets/mm3) or other known hematological/bleeding problems other than hemophilia A
• Intake of other investigational drugs within 1 month prior to study entry
• Need for pre-medication for FVIII infusions (e.g. antihistamines)
• Diastolic blood pressure >100 mm/Hg, which could not be controlled with antihypertensive medications