Merck Announces Top-Line Results from Phase 3 Trials Evaluating Gefapixant

Merck, known as MSD outside the United States and Canada, announced top-line efficacy results from two ongoing pivotal Phase 3 trials (COUGH-1 and COUGH-2) evaluating the efficacy and safety of gefapixant (MK-7264), an investigational, orally administered, selective P2X3 receptor antagonist, for the treatment of refractory or unexplained chronic cough. In these studies, the primary efficacy endpoints were met for the gefapixant 45 mg twice daily treatment arms – demonstrating a statistically significant decrease in 24-hour coughs per hour (average hourly cough frequency based on 24-hour sound recordings) versus placebo at 12 (COUGH-1) and 24 weeks (COUGH-2). The gefapixant 15 mg twice daily treatment arms did not meet the primary efficacy endpoint in either Phase 3 study. The safety and tolerability profile of gefapixant during the trials to date is consistent with the previously reported Phase 2 study. The trials will continue for long-term follow-up to collect additional safety data.

“The burden for patients faced with this disease underscores the need for effective therapeutic options for refractory and unexplained chronic cough,” said Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories. “We are pleased gefapixant at the 45 mg dose met the primary efficacy endpoints in both Phase 3 studies and we look forward to sharing the detailed findings at an upcoming medical meeting.”