FDA accepts gefapixant for review in cough, positioning Merck to get head start on Bayer and Bellus

The FDA has accepted a filing for approval of Merck’s P2X3 receptor antagonist gefapixant for review. Merck is seeking approval on the basis of phase 3 trials that linked the oral drug to improvements in several measures of chronic cough symptoms but confirmed tolerability concerns.

Gefapixant is at the front of a pack of P2X3 prospects in development at companies including Bayer, Bellus Health and Shionogi. Merck validated the target last year in a pair of phase 3 trials, COUGH-1 and COUGH-2, that found gefapixant drove relative risk reduction in 24-hour coughs per hour. Yet, 15% to 20% of subjects on the high dose dropped out due to adverse events.