24 January 2022 - Merck today announced that the US FDA has issued a complete response letter regarding Merck’s new drug application for gefapixant, the investigational, non-narcotic, orally administered selective P2X3 receptor antagonist, under development for the treatment of refractory chronic cough or unexplained chronic cough in adults.
In the complete response letter, the FDA requested additional information related to measurement of efficacy.