Study Evaluating Prophylaxis Treatment & Characterizing Efficacy, Safety, & PK Of B-Domain Deleted Recombinant FVIII

Inclusion Criteria

• •Male subjects, aged less than 6 years, with moderately severe to severe hemophilia A.
• •A negative FVIII inhibitor titer at screening, and a medical history negative for a past FVIII inhibitor.
• •At least 20 exposure days to any FVIII replacement product.
• •Adequate hepatic and renal function
• •CD4 count \> 400 cells/uL, and if receiving antiviral therapy must be on a stable regimen
• •Additional criteria for subjects participating in the PK assessment:
• •Male subjects as described immediately above except they must have a FVIII Activity of less than or equal to 1% confirmed by the central laboratory screening test
• •Age \< 6 years at time of PK assessment.
• •The subject's size is sufficient to permit PK-related phlebotomy.
• •The subject is able to comply with the procedures conducted during the PK assessment, including a mandatory 72-hour washout period preceding the PK assessment.