Gene therapy with valoctocogene roxaparvovec provided long-term benefits for patients with severe hemophilia A in clinical trials. A single infusion of the therapy resulted in increased factor VIII activity levels and significantly reduced annual bleeding rates and factor VIII utilization compared to baseline prophylactic therapy. The therapy was generally well-tolerated with most adverse events being mild to moderate and transient. Larger ongoing phase 3 trials continue to evaluate the efficacy and safety of this promising one-time gene therapy for hemophilia A.