Diacerein 1% cream is tolerable and superior to placebo for the treatment of epidermolysis bullosa simplex (EBS), according to the results of a randomized, vehicle-controlled, double-blind, phase 2/3 trial conducted in Salzburg, Austria, and published in the Journal of the American Academy of Dermatology.
The researchers sought to compare the effect of treatment with diacerein 1% cream vs placebo in reducing the number of blisters in patients with EBS. The diacerein 1% topical formulation was applied to defined skin areas in 17 patients with EBS.
In a 2-period crossover trial, patients were randomly assigned to receive either placebo or diacerein for 4 weeks and with a 3-month follow-up in period 1. After a washout, patients were crossed over in period 2.
The prespecified primary end point of the study was the percentage of participants with a >40% reduction from baseline in the number of blisters in selected treated areas through the end of each 4-week treatment episode. Secondary end points included the percentage of patients with ±10% recurrence of initial number of blisters at the end of both trial periods and the percentage of patients with a >40% reduction in blister numbers on treated body surface area from baseline to the end of the follow-up period.
The average size of the treatment area was 291 cm2. Overall, a total of 39 defined skin areas were treated, which were located on the arms or armpits (15), the legs (12), the trunk (5), the buttocks (4), or the feet (3).
In diacerein-treated patients, 86% in period 1 and 37.5% in period 2 met the primary end point compared with 14% and 17% of placebo-treated patients, respectively. This effect remained significant through and after the follow-up. After period 1, the mean percentage of blisters at the end of follow-up was much lower with diacerein than with placebo (10.2%; 95% CI, 0%-23% vs 40.7%; 95% CI, 5.4%-75.9%, respectively).
Changes in the absolute number of blisters were significant in the diacerein group only.
Overall, 60% of diacerein-treated patients achieved a >40% reduction in the number of blisters. No adverse events were reported in the treatment area.
The investigators noted that diacerein is the first targeted treatment for patients with EBS and the significant need for effective treatments and a cure in this population.
Wally V, Hovnanian A, Ly J, et al. Diacerein orphan drug development for epidermolysis bullosa simplex: a phase 2/3 randomized, placebo-controlled, double-blind clinical trial [published online February 1, 2018]. J Am Acad Dermatol. doi:10.1016/j.jaad.2018.01.019