Serlopitant for psoriatic pruritus: A phase 2 randomized, double-blind, placebo-controlled clinical trial

Background Pruritus, a common symptom of psoriasis, negatively affects quality of life; however, treatment of lesional skin does not consistently alleviate psoriatic itch. Objective To examine the effects of serlopitant, an oral, once-daily neurokinin 1 receptor antagonist, for treatment of psoriatic pruritus in a phase 2, randomized clinical trial (NCT03343639). Methods Patients (n = 204) were randomized to receive serlopitant, 5 mg, or placebo daily for 8 weeks. Eligible adult patients had plaque psoriasis for ≥6 months, plaques covering ≤10% of body surface area, pruritus for ≥4 weeks, and Worst Itch Numeric Rating Scale (WI-NRS) score ≥7 at the initial screening. Results Participants (54.2% women) had a mean age of 47.5 years and 85.2% were white. Mean baseline WI-NRS scores were 8.3 for serlopitant and 8.1 for placebo. The WI-NRS 4-point response rate at 8 weeks (primary end point) was 33.3% for serlopitant vs 21.1% for placebo (P = .028); at 4 weeks the rates were 20.8% for serlopitant vs 11.5% for placebo (P = .039). Treatment-related adverse events were reported for 4.9% of serlopitant-treated and 4.0% of placebo-treated patients. Limitations This was a phase 2 study with a small study population. Patients with severe psoriasis were excluded. Conclusion Serlopitant significantly reduced pruritus associated with mild to moderate psoriasis, supporting continued development of serlopitant for this patient population.