The two trials (COUGH 1 and 2) involved nearly 2,000 people with chronic cough due to unknown causes who were treated with one of two doses of gefapixant or placebo
Arial view of Merck headquarters in Darmstadt, Germany (Credit: Merck KGaA.)
Merck has announced top-line results from Phase 3 trials (COUGH-1 and COUGH-2) evaluating gefapixant, an investigational treatment for refractory or unexplained chronic cough (a cough lasting more than eight weeks).
COUGH-1 (NCT03449134) and COUGH-2 (NCT03449147) are randomised, double-blind, placebo-controlled, studies to assess the efficacy and safety of gefapixant in reducing cough frequency in adult participants.
The two trials (COUGH 1 and 2) involved nearly 2,000 people with chronic cough due to unknown causes who were treated with one of two doses of gefapixant or placebo.
Gefapixant 45mg demonstrates statistically significant decrease in 24-hour coughs per hour compared to placebo
The higher, 45mg dose of gefapixant met its primary objective of a statistically significant decrease in coughs per hour over 24 hours compared to placebo at week 12 and 24 in Phase 3 trials.
The lower 15mg dose did not meet the primary efficacy endpoint in either Phase 3 study.
The safety and tolerability profile of the drug during the trials to date is consistent with the earlier reported Phase 2 study.
The company stated that the trials will continue for long-term follow-up to accumulate additional safety data.
It is estimated that chronic cough affects 10% of the general adult population worldwide, and in up to 46% of these cases, no treatable cause can be identified despite a thorough diagnostic investigation.
Merck Research Laboratories chief medical officer global clinical development head and senior vice president Dr. Roy Baynes 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.”