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

A Global Epidemiologic Study to Determine the Prevalence of Neutralizing Antibodies and Related Adaptive Immune Responses to Adeno-Associated Virus (AAV) in Adults With Hemophilia

Assess the seroprevalence of neutralizing antibodies (NAb) to AAV in adults with severe hemophilia A (coagulation factor VIII [FVIII] <1%) or moderately severe to severe hemophilia B (coagulation factor IX [FIX] ≤2%).

Inclusion Criteria:

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

Exclusion Criteria:

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