Effectiveness of the P2X₃ Antagonist Gefapixant for Refractory Atopic Cough: A Retrospective Cohort Study

Atopic cough, arising from hyperresponsiveness of afferent airway C-fibers, is common, and cough is one of the commonest reasons for referral to respiratory clinic. Gefapixant is a first-in-class P2X₃ receptor antagonist recently approved for use in patients with refractory cough to inhibit airway C-fiber activation. We conducted this study to investigate the clinical effect of gefapixant in patients with refractory atopic cough that responded only partially to azelastine monotherapy.

This was a single-center retrospective observational study. Patients with refractory atopic cough received gefapixant. Collected retrospectively from medical records, data included cough symptom questionnaire responses and results from respiratory function tests, cough reflex sensitivity tests, and blood tests.

Data from 23 patients with refractory atopic cough were included in this study. Spirometry parameters, fractional exhaled nitric oxide levels, peripheral eosinophil counts, and IgE levels were unchanged after gefapixant treatment. Scores for the cough severity visual analog scale and Leicester cough questionnaire significantly improved after treatment with gefapixant (both p<0.01). Cough reflex sensitivity to inhaled capsaicin also significantly improved after treatment with gefapixant (p<0.01).

The P2X₃ antagonist gefapixant appeared to improve patient-reported symptoms and cough reflex hypersensitivity in a retrospective cohort of patients with refractory atopic cough. These findings suggest P2X₃ antagonists may be a treatment option for refractory atopic cough, possibly through possibly through reducing hypersensitivity of airway C fibers.