Natural history of wound closure and other clinical endpoints in epidermolysis bullosa: Lessons from a 90-day multicenter trial

Epidermolysis bullosa (EB) patients were followed for 90 days in a multicenter, randomized, double-blind, vehicle-controlled trial of SD-101 (topical cream, oil-in-water emulsion). Placebo (vehicle) arm data (N=87) provide insight into the natural history of wound closure and other clinical endpoints in EB. Eligible patients were those diagnosed with EB (simplex, recessive dystrophic, or junctional non-Herlitz), at least 1 month of age, and had a target wound between 10-50 cm2 in size that was present for ≥21 days. Patients were randomly assigned 1:1 to receive SD-101 6% allantoin cream or vehicle (0% allantoin) applied topically once daily to the entire body. A total of 87 patients were randomized to receive vehicle (0% allantoin) and followed for 90 days. Baseline characteristics were diverse with respect to patient age, sex, target wound size, target wound age, and EB type. Evaluations performed at Day 14, Day 30, Day 60, and Day 90 included: target wound closure, change in target wound size, Body Surface Area Index (BSAi) of EB lesions, BSAi of EB wounds, patient/caregiver-reported itching, and patient/caregiver-reported pain. Data on 87 vehicle-treated patients showed the following rates of complete wound closure, by visit: Day 14 (7%), Day 30 (23%), Day 60 (43%), and Day 90 (54%). Baseline parameters including patient age, target wound age, target wound size, and total body wound burden were factors in the rates observed for target wound healing. Reductions in mean values during the 90-day period were observed in a majority of the other clinical endpoint parameters. Given limited natural history, these data may inform future trial design, patient eligibility criteria, endpoint selection, and other clinical development aspects in EB.