Trial data published in the Journal of the American Academy of Dermatology support the safety and efficacy of serlopitant, an oral neurokinin 1 (NK1) receptor antagonist, for the treatment of pruritus in epidermolysis bullosa (EB).
Investigators conducted a 12-week double-blind placebo-controlled study in which 14 patients with EB were randomly assigned to receive serlopitant 5 mg daily (n=7) or placebo (n=7) for 8 weeks. A 4-week washout period and optional open-label extension period followed the initial trial. Patients were aged ≥13 years and had a baseline Numeric Rating Scale (NRS) pruritis score ≥4 out of a possible 10. Patients attended clinic visits at baseline and after 4 and 8 weeks of treatment. Patients were also contacted by phone at 12 weeks for a final assessment. The primary outcome measure was reduction of NRS score during the study period. Secondary outcome measures included change in NRS during dressing changes and reduction of wound size. A linear mixed model was used to assess the treatment outcomes in each study arm. Adverse events were also monitored throughout the trial.
Both study groups were similar in gender composition, baseline NRS score, and EB subtype. The mean (standard deviation [SD]) age was 27.6 (12.1) years in the serlopitant group and 22.9 (8.0) years in the placebo group. The most common EB subtype was recessive dystrophic epidermolysis bullosa (RDEB) (n=13; 93%). The serlopitant group experienced a 0.64-point NRS score reduction over placebo at 8 weeks, although this result failed to reach statistical significance (P =.11). The serlopitant group also did not achieve superior results in wound size reduction (P =.85) or itch related to dressing change (P =.85). A greater percentage of the serlopitant group (86%) achieved a ≥1-point reduction in NRS score by week 8 compared with placebo (57%), although this observation was not statistically significant (P =.35). No patients discontinued treatment due to adverse events (AE), and no serious treatment-related AEs were observed. The most common AE was nausea, which occurred in 2 patients on serlopitant and 1 patient on placebo (29% vs 14%).
A small treatment effect was observed in favor of serlopitant over placebo, although further study with a larger cohort is necessary to explore these findings. Serlopitant was generally well-tolerated, and no new safety signals were observed. Conclusions are limited by the small sample size and overrepresentation of RDEB compared with other EB phenotypes.
However, the investigators wrote, “The promising results of this study suggest that the [NK1 receptor] pathway merits further evaluation as a potential target for [patients with EB].”
Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Chiou AS, Choi S, Barriga M, et al. Phase 2 trial of a neurokinin-1 receptor antagonist for the treatment of chronic itch in epidermolysis bullosa patients: a randomized clinical trial [published online September 18, 2019]. J Am Acad Dermatol. doi:10.1016/j.jaad.2019.09.014