Gefapixant is in clinical development for the treatment of refractory or unexplained chronic cough. Cough is a normal reflex response to airway irritation, triggered by stimulation of airway cough receptors, which protect against choking and enhances airway clearance. Chronic refractory cough (defined as a cough lasting more than 8 weeks in adults) collectively refers to chronic cough that fails to respond to treatment of the underlying condition (in cases where an underlying condition has been identified) and unexplained chronic cough where the underlying cause cannot be identified. Current treatment targets the underlying condition and not the cough itself. In cases where there is no underlying condition, many current treatments are used to ‘mask’ symptoms but with limited effectiveness at treating the cough.
Gefapixant is an oral drug that blocks receptors in the sensory cells in the airways and lungs, potentially reducing cough frequency in patients with refractory or unexplained chronic cough. Preliminary results from early studies have demonstrated that gefapixant is efficacious and safe. If licenced, gefapixant could provide a treatment option for patients with refractory or unexplained cough who have no licensed therapies available and few effective therapies available.