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

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.