Burden of Cough in Refractory Chronic Cough Patients Enrolled in A Phase 2b Study of the P2X3 Antagonist BLU-5937

Refractory Chronic Cough (RCC) imposes a significant burden on patients’ quality of life (QoL). Tools such as the Leicester Cough Questionnaire (LCQ) are used to assess this impact of cough. We report the burden at baseline in RCC populations enrolled in a study of the P2X3 antagonist BLU-5937. SOOTHE (NCT04678206) was a phase 2b study in participants diagnosed with RCC for ≥1 year. Following a run-in period, participants with baseline awake cough frequency ≥25 or ≥10 - <25 coughs/h were randomized respectively to a main (n=249) or exploratory (n=61) populations for a treatment period. The burden of cough at the start of the treatment period was assessed using the LCQ, a 19-item QoL scale including physical, psychological and social domains. Participants in the main and exploratory populations reported baseline average total LCQ scores of 10.6 ±3.1 and 11.8 ±3.0, respectively. Participants also reported baseline average physical subdomain scores of 4.1 ±1.0 vs 4.6 ±1.1, psychological subdomain scores of 3.3 ±1.2 vs 3.6 ±1.2 and social subdomain scores of 3.2 ±1.2 vs 3.7 ±1.2. Most frequent burdens reported in both populations included lack of control of their cough, other people’s perception of them, annoyance of partner, family or friends, interruption of conversations and calls, as well as embarrassment and frustration due to cough. Despite differences in baseline cough frequency, both main and exploratory populations demonstrated similar burdens from cough on their quality of life based on total and domain scores of the LCQ.