The PD activity (expression, secretion, and localization of COL7 transgene in B-VEC) of B-VECwas demonstrated in six subjects (9 biopsy sites) in the Phase 1/2 study. The noncollagenousdomain 1 (NC1) and domain 2 (NC2) of COL7, and linear deposition at the dermal-epidermaljunction was demonstrated in skin biopsies harvested after the B-VEC treatment. These dataprovide mechanistic support and serve as confirmatory evidence of effectiveness of B-VEC forthe treatment of DEB wounds.