Efficacy and safety of gefapixant for chronic cough: a meta-analysis of randomised controlled trials

BACKGROUND: The efficacy and safety of gefapixant in adults with chronic cough remain unclear. Our objective was to assess the efficacy and safety of gefapixant using updated evidence. METHODS: MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL) and Embase databases were searched from inception through September 2022. Subgroup analysis based on dose of gefapixant (i.e. ≤20, 45–50 and ≥100 mg twice daily for low, moderate and high doses, respectively) was performed to explore a potential dose-dependent effect. RESULTS: Five studies involving seven trials showed the efficacy of moderate- or high-dose gefapixant for reducing objective 24-h cough frequency (estimated relative reduction 30.9% and 58.5%, respectively) (i.e. primary outcome) and awake cough frequency (estimated relative reduction 47.3% and 62.8%, respectively). Night-time cough frequency was only reduced with high-dose gefapixant. Consistently, the use of moderate- or high-dose gefapixant significantly alleviated cough severity and improved cough-related quality of life, but increased the risk of all-cause adverse events (AEs), treatment-related AEs and ageusia/dysgeusia/hypogeusia. Subgroup analysis showed dose dependency in both efficacy and AEs with a cut-off dose being ≥45 mg twice daily. CONCLUSIONS: This meta-analysis revealed dose-dependent efficacy and adverse effects of gefapixant against chronic cough. Further studies are required to investigate the feasibility of moderate-dose (i.e. 45–50 mg twice daily) gefapixant in clinical practice.