Merck announced that the US Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) regarding its New Drug Application (NDA) for gefapixant.
Gefapixant is a non-narcotic selective P2X3 receptor antagonist, being developed for the treatment of refractory chronic cough (RCC) or unexplained chronic cough (UCC) in adults.
The US health regulator declined to approve the company’s investigational drug for chronic cough, and sought additional information on its effectiveness, reported Reuters.
Merck stated that the CRL was not related to the safety of gefapixant and is reviewing the letter with plans to meet with the agency to discuss further steps.
Merck Research Laboratories senior vice president and global clinical development head, chief medical officer Roy Baynes said: “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.
“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 US FDA has initially accepted the company’s NDA for gefapixant in March 2021.
Last week, Japan’s health regulator MHLW has approved gefapixant, to be marketed under the brand name Lyfnua, to treat refractory or unexplained chronic cough in adults.
Gefapixant remains as an investigational treatment outside of Japan and is currently being reviewed by other regulatory agencies in other territories.
The FDA’s decision could delay the regulatory approval of the drug, and would potentially benefit Bellus Health with its rival candidate BLU-5937, reported Reuters.
Last month, Bellus has announced positive results from a mid-stage study of BLU-5937 and its plans to commence a late-stage trial in the second half of this year.
Both gefapixant and BLU-5937 target patients suffering from RCC, which persists after the treatment of underlying health conditions such as asthma.
