Merck's Gefapixant For Chronic Cough Slapped With FDA Complete Response Letter

The FDA has issued a Complete Response Letter (CRL) to Merck Co & Inc's MRK gefapixant for refractory chronic cough (RCC) or unexplained chronic cough (UCC) in adults.

• Gefapixant is an investigational, non-narcotic, orally administered selective P2X3 receptor antagonist.
• In March 2021, the FDA accepted gefapixant marketing application. 
• In the CRL, the FDA requested additional information related to efficacy measurement. 
• The CRL was not related to the safety of gefapixant. Merck is reviewing the letter and will meet with the agency to discuss the next steps.
• Last week, the Japan Ministry of Health, Labor and Welfare (MHLW) approved Lyfnua (gefapixant) 45 mg for adults with refractory or unexplained chronic cough. 
• Outside of Japan, gefapixant is an investigational treatment and is still under review by other regulatory bodies.
• Price Action: MRK shares are down 0.38% at $79.68 during the premarket session on the last check Monday.