Study of Safety And Efficacy Of ReFacto AF In Previously Untreated Hemophilia A Patients In The Usual Care Setting

• Annualized bleeding rates. [ Time Frame: 12 years (study duration) ] [ Designated as safety issue: No ]
• Responses to the first on-demand treatment with Refacto AF for all new bleeds. [ Time Frame: 12 years (study duration) ] [ Designated as safety issue: No ]
• The number of ReFacto AF infusions to treat each new bleed. [ Time Frame: 12 years (study duration) ] [ Designated as safety issue: No ]
• The number of bleeds within 48 hours of a prophylaxis dose of ReFacto AF. [ Time Frame: 12 years (study duration) ] [ Designated as safety issue: No ]
• The average infusion dose and total factor consumption [ Time Frame: 12 years (study duration) ] [ Designated as safety issue: No ]
• The number of subjects who require dose escalation of their prescribed prophylaxis regimen during their participation in this study. [ Time Frame: 12 years (study duration) ] [ Designated as safety issue: No ]
• The incidence of less-than-expected therapeutic effect (LETE). [ Time Frame: 12 years (study duration) ] [ Designated as safety issue: No ]

Study to evaluate the safety and effectiveness of ReFacto AF for the treatment of severe hemophilia A in patients who have not yet received treatment for their hemophilia. Study subjects will be males less than 6 years old who have not taken any clotting factor or other blood products before the study. The safety and effectiveness of ReFacto AF will be determined in this study by tests and procedures done at the doctor's office.

Regulatory Commitment

Inclusion Criteria:

• Male subjects <6 years of age with severe hemophilia A (FVIII:C <1%) based on clinical records, including newborns.
• No prior exposure to factor products or any blood products.

Exclusion Criteria:

• Presence of any bleeding disorder in addition to hemophilia A.
• Treatment with any investigational agent or device within the past 30 days.
• Any condition(s) that compromises the ability to collect study-related observations, or that poses a contraindication to study participation (these conditions include, but are not limited to, inadequate medical history to assure study eligibility; and expectation of poor adherence to study requirements).