Merck Provides U.S. and Japan Regulatory Update for Gefapixant

Merck, known as MSD outside the United States and Canada, announced that the U.S. Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) regarding Merck’s New Drug Application (NDA) for gefapixant, the investigational, non-narcotic, orally administered selective P2X3 receptor antagonist, under development for the treatment of refractory chronic cough (RCC) or unexplained chronic cough (UCC) in adults. In March 2021, Merck announced that the FDA accepted the company’s NDA for gefapixant. In the CRL, the FDA requested additional information related to measurement of efficacy. The CRL was not related to the safety of gefapixant. Merck is reviewing the letter and will meet with the agency to discuss next steps.

“We remain committed to advancing gefapixant for patients with refractory or unexplained chronic cough and will work with the FDA to address the agency’s feedback,” said Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories. “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.”

Last week, the Japan Ministry of Health, Labor and Welfare (MHLW) approved LYFNUA (gefapixant) Tablets 45 mg for adults with refractory or unexplained chronic cough. In Japan, LYFNUA is the planned trademark for gefapixant; the trademark for gefapixant in other countries has not been approved. Outside of Japan, gefapixant is an investigational treatment and is still under review by other regulatory bodies.