This study will seek to determine the safety, tolerability, kinetics and efficacy of a single IV infusion of ZS802.~Hemophilia A is a genetic bleeding disorder resulting in the lack of ability to produce blood-clotting factor VIII (FVIII). Individuals with hemophilia A suffer repeated bleeding events, which can cause chronic joint disease and sometimes leads to death due to the inability for blood to clot efficiently. The current treatment is intravenous infusion of FVIII protein products, either prophylactically or in response to bleeding. ZS802 is an adeno-associated viral (AAV) vector designed to drive expression of the human factor VIII (hFVIII) transgene and raise circulating levels of endogenous FVIII.~6 patients will be enrolled sequentially every 3 weeks or more between cohorts and administered with single infusion of ZS802. Dose escalation may occur based on the safety and FVIII activity on steady state. The dose levels are as follows: 1. 2.0×10^13vg/kg; 2. 6.0×10^13vg/kg. Subjects will provide informed consent and then undergo screening assessments up to 6-8weeks prior administration of ZS802. All subjects will undergo 52 weeks safety and efficacy observation.
A non-randomized, open-label, dose-escalation study to evaluate the safety, tolerability, kinetics and efficacy of a single intravenous infusion of ZS802 in hemophilia A subjects with endogenous FVIII ≤2%.