Serlopitant for the treatment of chronic pruritus: Results of a randomized, multicenter, placebo-controlled phase 2 clinical trial

Abstract

The substance P/neurokinin 1 receptor pathway is critical in chronic pruritus; anecdotal evidence suggests that antagonism of this pathway can reduce chronic itch. To assess the safety and efficacy of the substance P/neurokinin 1 receptor antagonist serlopitant in treating chronic pruritus. Eligible patients with severe chronic pruritus who were refractory to antihistamines or topical steroids were randomized to serlopitant, 0.25, 1, or 5mg, or to placebo, administered once daily for 6weeks as monotherapy or with midpotency steroids and emollients. The primary efficacy end point was percentage change in visual analog scale pruritus score from baseline. Serlopitant treatment resulted in a dose-dependent decrease in pruritus. The mean percentage decreases from baseline visual analog scale pruritus scores were statistically significantly larger with the 1-and 5-mg doses of serlopitant (P=.022 and P=.013, respectively) than with placebo at week 6. No significant safety or tolerability differences were detected among the groups. The sample size was insufficient for subgroup analyses of the efficacy of serlopitant for chronic pruritus on the basis of underlying conditions. Serlopitant, 1mg and 5mg daily, was associated with a statistically significant reduction in chronic pruritus and was well tolerated (NCT01951274).