Long-Term Safety and Tolerability of Beremagene Geperpavec-svdt (B-VEC) in an Open-Label Extension Study of Patients with Dystrophic Epidermolysis Bullosa.

BACKGROUND

Patients with dystrophic epidermolysis bullosa have pathogenic variants in COL7A1, leading to skin fragility. Beremagene geperpavec-svdt (B-VEC) is a modified, herpes simplex virus type 1-based gene therapy vector that topically delivers COL7A1 to dystrophic epidermolysis bullosa wounds. In a phase III study, B-VEC significantly improved wound healing at 3 and 6 months compared with placebo.

OBJECTIVE

We aimed to evaluate the safety and tolerability of B-VEC beyond 6 months in patients with dystrophic epidermolysis bullosa.

METHODS

An open-label extension study was conducted with 47 subjects (24 rollover from phase III; 23 treatment naïve) receiving B-VEC weekly to target wound areas for up to 112 weeks (median 81 weeks). Safety was assessed by adverse events. Treatment satisfaction and quality of life were assessed with patient-reported outcomes as exploratory measures of efficacy. Selected wounds from phase III rollover subjects were assessed for closure.

RESULTS

Thirty-five subjects (74.5%) reported one or more adverse events; most were mild or moderate in severity. Fourteen subjects experienced 17 serious adverse events and ten experienced 14 severe adverse events; none was considered treatment related. No adverse events led to treatment or study discontinuation. Patient-reported outcomes indicated high levels of treatment satisfaction, but were inconclusive with regard to quality of life. Among rollover subjects, wounds that received B-VEC during phase III maintained high closure rates during the open-label extension (range 61.1-89.5%, assessed baseline to month 12).

LIMITATIONS: This was an open-label design, with a variable follow-up.

CONCLUSIONS

Patients undergoing extended B-VEC treatment maintained high satisfaction and continued to respond to treatment with no new safety signals detected in the open-label extension study, supporting the continuous use of B-VEC.

CLINICAL TRIAL REGISTRATION: NCT04917874 (date of trial registration: 8 June, 2021).