Demographic, clinical, and patient-reported outcome data from 2 global, phase 3 trials of chronic cough

Background: The current characterization of patients with refractory or unexplained chronic cough (RCC and UCC, respectively) primarily stems from relatively small clinical studies. Objective: To report the baseline medical history and clinical characteristics of individuals with RCC or UCC who were enrolled in COUGH-1 and COUGH-2, 2 large, global, phase 3 trials of gefapixant, a P2 × 3-receptor antagonist. Methods: Adults with a chronic cough lasting for more than 1 year, diagnosis of RCC or UCC, and score greater than 40 mm on a 100-mm cough severity visual analog scale at both screening and baseline were eligible for enrollment. Demographics, medical history, and cough characteristics were collected at baseline. Cough-related measures included objective cough frequency, cough severity visual analog scale, Leicester Cough Questionnaire, and Hull Airway Reflux Questionnaire. The data were summarized using descriptive statistics. Results: Of 2044 participants, 75% were women; mean age was 58 years, and mean cough duration was approximately 11 years. Among all participants, 73% were previously diagnosed with asthma, gastroesophageal reflux disease, or upper airway cough syndrome. The mean Leicester Cough Questionnaire total score was 10.4, with domain scores reflecting impaired cough-specific quality of life across physical, psychological, and social domains. The mean Hull Airway Reflux Questionnaire score was 39.6, with some of the most burdensome reported items being consistent with features of cough-reflex hypersensitivity. Participant characteristics and cough burden were comparable across geographic regions. Conclusion: Participants with RCC or UCC had characteristics consistent with published demographics associated with chronic cough. These data reflect a global population with burdensome cough of long duration and substantial impairment to quality of life. Clinical trial registration: ClinicalTrials.gov Identifiers: COUGH-1, NCT03449134 (https://www.clinicaltrials.gov/ct2/show/NCT03449134); COUGH-2, NCT03449147 (https://clinicaltrials.gov/ct2/show/NCT03449147).