FDA declines approval of gefapixant for chronic cough

The FDA has issued a complete response letter declining to approve a new drug application for gefapixant to treat adults with refractory and unexplained chronic cough, according to a press release issued by Merck.

Gefapixant (Merck) is an investigational, non-narcotic, orally administered selective P2X3 receptor antagonist.

In the complete response letter, the FDA requested additional information related to measurement of efficacy. The complete response letter was not related to the safety of gefapixant, according to the release. Merck stated it is reviewing the letter and will meet with the FDA 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,” Roy Baynes, MD, senior vice president, head of global clinical development and chief medical officer at Merck Research Laboratories, said in the release. “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.”

The prevalence of chronic cough is estimated to occur in 5% of U.S. adults.

In March 2021, the FDA accepted for review Merck’s new drug application for gefapixant for refractory and unexplained chronic cough in adults. The application was based on results from the COUGH-1 and COUGH-2 clinical trials, which demonstrated efficacy and safety of twice-daily gefapixant for up to 52 weeks in patients with refractory or unexplained chronic cough.

Merck announced that in January, the Japan Ministry of Health, Labor and Welfare approved gefapixant 45 mg tablets for adults with refractory or unexplained chronic cough. Outside of Japan, gefapixant remains an investigational treatment that continues to be under review, according to the release.