The latest complete response letter (CRL) for gefapixant comes even though the drug is already on the market in Europe and Japan under the Lyfnua brand name, and less than two years after the FDA first rejected it in January 2022.
MSD – known as Merck & Co in North America – had submitted the oral selective P2X3 receptor antagonist to the US regulator as a treatment for refractory chronic cough (RCC) or unexplained chronic cough (UCC) in adults.
In a statement, the drugmaker said the FDA had concluded that its application “did not meet substantial evidence of effectiveness for treating RCC and UCC,” and it is now reviewing the next steps for the programme.
