Gefapixant: First Approval.

Gefapixant (Lyfnua; Merck & Co.) is a first-in-class, non-narcotic, selective P2X3 receptor antagonist being developed for the treatment of refractory chronic cough or unexplained chronic cough. Marketing approval for gefapixant is being sought in the EU and USA, and the drug was recently approved for marketing in Japan as treatment for refractory or unexplained chronic cough. This article summarizes the milestones in the development of gefapixant leading to this first approval.