Global Epidemiologic Study of Preexisting Immunity to AAV in Adults With Severe Hemophilia

Inclusion criteria

• Participant is male between 18 and 75 years old at the time of screening.
• Established severe hemophilia A (plasma Factor VIII (FVIII) activity <1%) or B (plasma Factor IX (FIX) activity ≤2%).
• Provision of signed informed consent form (ICF).
• Participant is willing and able to comply with the requirements of the protocol.

Exclusion criteria

• Bleeding disorder(s) other than hemophilia A or B.
• Personal laboratory evidence of having developed inhibitors to FVIII or FIX protein at any time (≥0.6 Bethesda Units [BU] on any single test).
• Currently receiving systemic immunosuppressive therapy, cytotoxic chemotherapy, immunoglobulin therapy, or monoclonal antibody therapy.
• Received systemic antiviral and/or interferon therapy within 30 days of blood draw, with the exception of treatment for human immunodeficiency virus (HIV).
• Currently receiving ribavirin and/or interferon based therapy for active hepatitis C virus (HCV).
• Received immunoglobulin therapy or plasma infusion within 120 days of the blood draw.
• Has a known immune deficiency other than HIV.
• Has lymphocyte or plasma cell malignancies.
• Participant is a family member or employee of the investigator.