Castle Creek Pharmaceuticals (CCP) has reported positive data from a Phase ll trial of diacerein 1% ointment (CCP-020) for the treatment of epidermolysis bullosa simplex (EBS).

The trial has validated a new disease-specific investigator’s global assessment (IGA) scale designed for overall clinical evaluation defining EBS-affected skin as either clear, near-clear, mild, moderate, and severe based on the presence or absence of blisters and factors such as the size, erosions, crusting, and erythema.

Before validating the new IGA scale, investigators of the trial reviewed blinded photographs of affected body locations received from the enrolled patients at each visit.

The Phase ll trial’s primary endpoint features the proportion of patients with moderate-to-severe lesions who achieved treatment success, defined as an IGA score of zero or one on a five-point scale at week 16 of treatment with at least a two-point reduction in the IGA score compared to baseline.

“We believe this new IGA scale is a tremendous step forward for EBS research.”

Other clinical endpoints comprise the proportion of patients with a two-point reduction from baseline to week 16 and the mean decrease in IGA score.

CCP president and chief medical officer Greg Licholai said: “Developing therapies for rare skin diseases like EBS comes with certain challenges because there is often limited or no prior clinical research providing disease progression insights that can serve as the foundation for clinical endpoints.

“As we work to support an underserved patient population, we have a responsibility to develop effective protocols that can be applied to current and future clinical studies, and we believe this new IGA scale is a tremendous step forward for EBS research.”

In a previous Phase ll study of CCP-020, the company employed blister count reduction as the primary efficacy endpoint, as the instrument for evaluating the effects of pharmacological interventions on overall disease severity for EBS patients was not available at that time.