Study of a Gene Therapy Treatment for Hemophilia A

Inclusion Criteria: * Have a negative anti-AAV-Spark200 neutralizing antibody (NAb) test result. * Are adult males with severe or moderately severe hemophilia A, defined as endogenous FVIII activity ≤3%, as documented by a certified laboratory (historically or during the Screening Period) and where the FVIII:C level is measured more than 96 hours after the prior dose of an extended-half-life FVIII * Have ≥150 documented exposure days to an FVIII protein product such as recombinant, plasma-derived, or extended half-life FVIII product * Have no prior history of hypersensitivity or anaphylaxis associated with the administration of any FVIII product. * Have screening hepatic ultrasound without evidence of cirrhosis and no laboratory or clinical evidence per the Investigator's judgment of advanced liver disease or cirrhosis. * Have a negative test for inhibitor against FVIII (ie, \<0.6 Bethesda units \[BU\]) during screening. * Have no documented FVIII inhibitor (ie, \<0.6 BU), FVIII half-life \<6 hours, or FVIII recovery \<66% in the 5 years prior to screening. * Candidates who completed successful immune tolerance induction (ITI) at least 5 years before screening are eligible, provided they have had no evidence of inhibitor recurrence (permanent or temporary) within 5 years prior to screening as may be indicated by detection of an inhibitor, FVIII half-life \<6 hours, or FVIII recovery \<66% since completing ITI. * If human immunodeficiency virus (HIV)-positive at screening, ha…