Lead-in Study to Collect Prospective Efficacy and Safety Data of Current FVIII Prophylaxis Replacement Therapy in Adult Hemophilia A Participants

Inclusion criteria

• Able and willing to provide written informed consent.
• Males ≥18 years of age.
• Clinically severe hemophilia A
• Previous exposure to FVIII therapy
• No prior history of hypersensitivity or anaphylaxis associated with an FVIII or intravenous immunoglobulin administration.
• No measurable inhibitor against FVIII
• Willing to participate and receive treatment in a future Spark hemophilia A gene therapy study.

Exclusion criteria

• Documented active hepatitis B or C within the past 12 months of Screening
• Currently on antiviral therapy to treat hepatitis B or C;
• Documented significant liver disease within the past 6 months of Screening
• Have serological evidence of HIV-1 or HIV-2
• Anti-AAV-Spark 200 neutralizing titers ≥1:1
• Previously received SPK-8011;
• Previously dosed with any investigational or approved gene therapy product at any time or treated with an investigational drug within the last 12 weeks;
• Planned surgical procedure in the next 12 months requiring FVIII prophylactic treatment.
• Any history of chronic infection or other chronic disease, concurrent clinically significant major disease (such as liver abnormalities or type I diabetes) including active malignancy, except for non-melanoma skin cancer, any other condition or any other unspecified reasons that, in opinion of the Investigator or Sponsor, makes the participant unsuitable for participation and dosing in a future clinical study for Spark's hemophilia A gene therapy.
• Unable or unwilling to comply with the schedule of visits and/or study assessments described in the protocol.