Recombinant adeno-associated virus (AAV) -based vectors expressing therapeutic gene products have shown great promise for human gene therapy. A recent milestone has been the safety and efficacy observed using recombinant AAV2 expressing retinal pigment epithelial associated 65KDa protein for Leber Congenital Amaurosis. This review summarizes manufacturing and characterization of 'AAV2-hRPE65v2', the vector used in one completed Phase I/II clinical trial. Regulatory challenges and strategies that were successfully used for this groundbreaking trial are described.