Merck said on Tuesday it got top-line efficacy results from two its pivotal Phase 3 trials (COUGH-1 and COUGH-2) testing 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, Merck said the testing met the primary efficacy endpoints for the gefapixant 45 mg twice daily treatment arms – showing 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 failed to 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, Merck said. The trials will continue for long-term follow-up to collect additional safety data.
Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer said: “The burden for patients faced with this disease underscores the need for effective therapeutic options for refractory and unexplained chronic cough. 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.”