Recessive dystrophic epidermolysis bullosa (RDEB) is a rare, life-threatening bullous genodermatosis (1, 2). Genetic mutations in the COL7A1 gene lead to lack of functional type VII collagen (C7), a large triple-helical protein found beneath the lamina densa (2-4). C7 contains 2 noncollagenous domains (NC1 and NC2) and a central collagenous domain, forming anchoring fibrils (AFs) that are critical to dermal-epidermal basement cohesion (2, 4). Mutations in COL7A1 lead to disruptions in keratinocyte adhesion, reducing mucocu-BACKGROUND. Recessive dystrophic epidermolysis bullosa (RDEB) patients have mutations in the COL7A1 gene and thus lack functional type VII collagen (C7) protein; they have marked skin fragility and blistering. This single-center phase 1/2a open-label study evaluated the long-term efficacy, safety, and patient-reported outcomes in RDEB patients treated with gene-corrected autologous cell therapy. METHODS. Autologous keratinocytes were isolated from participant skin biopsies. Epidermal sheets were prepared from cells transduced with a retrovirus carrying the full-length human COL7A1 gene. These gene-corrected autologous epidermal sheets measured 5 × 7 cm (35 cm 2) and were transplanted onto 6 wound sites in each of 7 adult participants (n = 42 sites total) from 2013 to 2017. Participants were followed for 2 to 5 years. RESULTS. No participants experienced any serious related adverse events. Wound healing of 50% or greater by Investigator Global Assessment was present in 95% (36 of 38) of treated wounds versus 0% (0 of 6) of untreated control wounds at 6 months (P < 0.0001). At year 1, 68% (26 of 38) of treated wounds had 50% or greater healing compared with 17% (1 of 6) of control wounds (P = 0.025). At year 2, 71% (27 of 38) of treated wounds had 50% or greater healing compared with 17% (1 of 6) of control wounds (P = 0.019). CONCLUSION. C7 expression persisted up to 2 years after treatment in 2 participants. Treated wounds with 50% or greater healing demonstrated improvement in patient-reported pain, itch, and wound durability. This study provides additional data to support the clinically meaningful benefit of treating chronic RDEB wounds with ex vivo, C7 gene-corrected autologous cell therapy. This approach was safe and promoted wound healing that was associated with improved patientreported outcomes. TRIAL REGISTRATION. Clinicaltrials.gov identifier: NCT01263379.

The findings reported here for the SNaP Wound Care System are similar to published reports for powered negative-pressure wound therapy devices for the treatment of highly challenging lower extremity wounds. This study suggests that the SNaP Wound Care System may be a useful addition to the techniques available to the wound care clinician.

The SNaP System and an existing electrically powered negative-pressure wound therapy system have similar biomechanical properties and functional wound-healing benefits. The potential clinical efficacy of the SNaP device for the treatment of wounds is supported.