A randomized, double-blind, placebo-controlled, parallel-group Phase 2b trial of P2X3 receptor antagonist sivopixant for refractory or unexplained chronic cough

This Phase 2b, randomized, double-blind trial examined the efficacy and safety of sivopixant versus placebo in 406 adult patients with refractory or unexplained chronic cough. The primary endpoint was the change from baseline in 24-hour cough frequency (coughs/hour); secondary endpoints included the ratio of coughs per hour while awake and asleep at 4 weeks versus baseline and changes from baseline in cough severity, Leicester Cough Questionnaire total score, and Patient Global Impression of Change. During the study, cough counts were objectively measured using the Vitalograph VitaloJAK cough monitor.