Merck's Chronic Cough Treatment Candidate Receives Second Time FDA Rejection

The FDA issued a Complete Response Letter (CRL) regarding Merck & Co Inc's MRK New Drug Application (NDA) for gefapixant under development for the treatment of refractory chronic cough (RCC) or unexplained chronic cough (UCC) in adults. 

In the CRL, the FDA concluded that Merck's application did not meet substantial evidence of effectiveness for treating RCC and UCC. 

The CRL was not related to the safety of gefapixant. Merck is reviewing the FDA's feedback to determine the next steps.

In January 2022, the FDA issued a CRL for the gefapixant application and requested additional information related to efficacy measurement.

Chronic cough is defined as a cough lasting longer than eight weeks. In adults with RCC, the cough persists despite appropriate treatment of underlying conditions such as asthma or gastroesophageal reflux disease, and UCC is a cough where the underlying cause cannot be identified despite a thorough evaluation.

In November, a panel of advisors to the FDA expressed concerns about the efficacy of gefapixant, highlighting a lack of convincing evidence to support the drug's clinical benefits for patients and casting doubt on its potential approval. 

Reuters notes that the FDA's ruling provides a window of opportunity for competitor GSK Plc's GSK upcoming chronic cough remedy, camlipixant, currently in Phase 3 study, with expected approval and launch in 2026.

Price Action: MRK shares are up 1.36% at $106.79 premarket on the last check Thursday.