This is a Phase 2, double-blind, randomized, vehicle-controlled study designed to evaluate efficacy, safety, and tolerability of topically applied TCP-25 gel in patients with confirmed DEB or JEB. The study will implement intrasubject randomization, ie, a pair of matching index wounds will be randomly assigned to be treated with a local application of either TCP 25 gel or vehicle gel.

The study will include a Screening Period, a Treatment Period (Days 1 to 56, with study visits conducted every 2 weeks, including the baseline [Day 1], Day 14, Day 28, Day 42, and Day 56 visits) and a Safety Follow-up conducted via a telephone/video call at approximately 14 days after the last dose of the IMP. Patients will undergo efficacy, safety, tolerability, and PK assessments at scheduled visits. For evaluation of the primary efficacy endpoint, a trained clinician will take the images of the index wounds at all scheduled visits from baseline through Day 56 (Visit 6) using 3D digital photography and software for wound measurement.

Inclusion Criteria:

• Male or female patients with documented diagnosis of DEB or JEB, confirmed by genetic testing and/or by a skin biopsy with immunofluorescence mapping.
• Patients ≥4 years old. Note: Initially, patients ≥12 years will be enrolled. Enrollment will be open to 4 to 11 year old pediatric patients (both inclusive), after a DMC reviews and provides a positive opinion regarding the safety and tolerability of the IMP in at least 3 patients 12 to 18 years old who have completed at least 4 weeks of IMP use.

Exclusion Criteria:

• The patient has any subtype of EB other than DEB or JEB.
• The patient is currently being treated or planned to be treated with systemic antibiotics.

Note: Use of preventive and/or anti-inflammatory antibiotic treatment, including doxycycline, on an established treatment regimen (stable dose for ≥6 weeks before the Baseline Visit) is permitted. Use of topical antibiotics on the index wounds within 7 days before the Baseline Visit is prohibited.

• Use of systemic corticosteroids >0.2 mg/kg prednisone dose equivalent per day within 30 days or use of topical corticosteroids on index wounds within 7 days before the Screening Visit.

Note: Corticosteroids for inhalation, ophthalmic, or intranasal use are permitted.

• The patient has a history of or current malignancy over the index wound, eg, basal cell carcinoma or squamous cell carcinoma.