Safety and Efficacy of Diacerein 1% Ointment for Subjects With Epidermolysis Bullosa Simplex (EBS)

Epidermolysis bullosa simplex (EBS) is a rare genetic skin disease characterized by fragility of the skin and mucous membranes resulting in painful blisters and erosions after minor trauma. The purpose of this study is to compare the efficacy of diacerein 1% ointment to vehicle ointment when applied once-daily for 8 weeks in subjects with EBS.

The study is an international, multicenter, randomized, double-blind, vehicle-controlled, parallel group study to evaluate the safety and efficacy of diacerein 1% ointment for the treatment of subjects with EBS. Participants were assigned to study groups receiving either diacerein 1% ointment or vehicle ointment for 8 weeks, followed by an 8 week follow-up period. Approximately 80 subjects were to be randomized to one of the 2 treatment groups.

The primary objective of this study is to compare the efficacy of diacerein 1% ointment to vehicle ointment based on reduction in body surface area (BSA) of EBS lesions being treated when applied once-daily for 8 weeks in subjects with EBS. The secondary objectives are to compare the effects of diacerein 1% ointment to vehicle ointment in subjects with EBS in changes in Investigator Global Assessment (IGA) scores, pain, pruritus, mobility, and safety and tolerability.

Eligibility Criteria:
Key Inclusion Criteria:

* Subject is at least 4 years of age at Screening
* Subject has a documented genetic mutation consistent with EBS. Gene mutations acceptable for inclusion are as follows: KRT5, KRT14, PLEC1, TGM5, PKP1, DSP, FERMT1, EXPH5, DST, KLHL24.
* Subject has an Assessment Area of EBS lesions to be treated, that is ≥2% body surface area (BSA) and the EBS lesions are in one or both of the following body areas:

  * Localized: plantar and/or palmar areas
  * Generalized: arms, legs, torso, hands and feet
* Subject's EBS lesions in the Assessment Area have an Investigator's Global Assessment (IGA) score of ≥3
* Subject/caregiver agrees to not use any topical therapies other than the study medication that might influence the status of the EBS lesions during the duration of the study
* Subject is non-pregnant as confirmed by a negative urine pregnancy screen, non-lactating and is not planning for pregnancy during the study period
* If the subject is a woman of childbearing potential, agrees to use an approved effective method of birth control
* Subject is in good general health and free of any known disease state or physical condition which might impair evaluation of the EBS lesions or which exposes the subject to an unacceptable risk by study participation

Key Exclusion Criteria:

* Subject has EBS lesions to be treated that are infected
* Subject has used any diacerein containing product within 6 months prior to Screening
* Subject has used systemic immunotherapy or cytotoxic chemotherapy within 60 days prior to Screening
* Subject has used systemic steroidal therapy or has used topical steroidal therapy on the EBS lesions to be treated within 30 days prior to Baseline
* Subject has evidence of a systemic infection or has used systemic antibiotics within 7 days prior to Screening
* Subject is currently using systemic analgesics and/or anti-histamine therapy, for treatment of EBS lesions unless on a stable regimen (i.e., the same dosing regimen) for at least 4 weeks prior to Screening
* Subject has used any systemic diuretics or cardiac glycosides or any systemic product that might put the subject at undue risk
* Subject has used any topical product containing allantoin on the EBS lesions to be treated within 30 days prior to Screening
* Subject has a current malignancy, or a history of treatment for a malignancy within 2 years prior to Screening
* Subject currently has diabetes mellitus (HbA1c ≥6.5%) or controlled diabetes (HbA1c \< 6.5%)
* Subject has a history of cardiac, hepatic (ALT and or AST \>2x ULN, Total bilirubin \>1.5x ULN at Screening), or renal disease (eGFR\<30 ml/min/1.73 m\^2)
* Subject has a non-EBS skin disease or condition (e.g., sunburn) that might put the subject at undue risk by study participation or interferes with the study medication application or the study assessments