Merck’s cough treatment, gefapixant declined for approval by FDA

The FDA has requested additional data on the measurement of efficacy for gefapixant.



Merck has announced that the United States (U.S.) Food and Drug Administration issued a Complete Response Letter (CRL) regarding their New Drug Application (NDA) for gefapixant. In May 2021, the pharmaceutical company announced that the agency accepted the NDA for the experimental drug. In the CRL, the drug administration has requested added information from the pharmaceutical giant on the drug’s effectiveness, however Merck noted that the non-approval was not related to the drug’s safety. Merck has stated that they would meet with the FDA to discuss the next steps for the oral drug. Gefapixant is a non-narcotic, investigational, orally administered selective P2X3 receptor antagonist. Gefapixant would be the first remedy for people with ongoing cough after treatment of underlying conditions such as asthma or unexplained chronic cough.


“We believe there is a significant unmet need to help patients manage their chronic cough, as there are no available treatment options indicated in the U.S. specifically for this condition,” stated Dr Baynes senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories. The company’s shares dropped by 0.5% at $79.6 before the stock market closed, following the announcement. Japan’s Ministry of Health, Labour and Welfare approved LYFNUA (gefapixant) Tablets 45 mg for adults with refractory or unexplained chronic cough last week. Gefapixant has been trademarked under the brand name LYFNUA in Japan while the trademark has not been authorized in other countries. Gefapixant is still an investigational drug outside Japan and under review by regulatory bodies.