Efficacy of gefapixant, a P2X(3) antagonist, for lung cancer-related cough: a case report

Cough is a frequent symptom accompanied by lung cancer. More potent antitussive treatment for this complex and distressing symptom is required, but anti-cancer chemotherapy cannot fully manage the cough. Inhibition of vagal nerves might control coughing in patients with troublesome lung cancer-related cough and P2X(3) inhibitory therapy may be useful for targeting neuronal function. We report the case of a woman in her late 70s who never smoked and had advanced lung cancer. She visited our hospital complaining of serious deterioration of a non-productive cough. She was diagnosed with relapse of lung cancer, but she requested 2-week anti-tussive therapy before second-line chemotherapy. Gefapixant (P2X(3) antagonist) add-on at a dose of 90 mg/day (45 mg twice daily as the usual dosage in Japan) improved her cough as indicated by an improvement in the visual analog scale for cough from 70 to 20 mm and in the Japanese version of the Leicester Cough Questionnaire from 8.2 to 16.3, despite a deterioration in lung cancer after 2 weeks. There are no current guidelines for cough accompanied by lung cancer; however, our findings suggest that P2X(3) inhibition is a potent therapeutic option for lung cancer-related cough.