WASHINGTON – A new oral drug that blocks a nerve ion channel was generally tolerable and effective at reducing chronic, refractory cough in a placebo-controlled, dose-ranging, phase II study with 252 patients.
A 50 mg b.i.d dosage of MK-7264 cut cough frequency by at least 30% in 80% of patients, compared with 44% of patients on placebo, Jaclyn A. Smith, MD, said at an international conference of the American Thoracic Society.
At that dosage, 48% of patients reported some change in their taste sensations, an expected drug effect, with about 40% characterizing it as very bothersome or extremely bothersome. An additional 9% reported a complete loss of taste. However, only 6 patients out of 63 randomized to this dosage stopped taking their medication, suggesting that the drug was tolerable for most patients. The results also suggested that lower dosages with less potent taste adverse effects produced significant cough reductions in some patients.
“Patients with chronic, refractory cough are often “willing to accept some taste change to reduce their cough count. Patients are willing to put up with the taste side effects,” Dr. Smith said in a video interview.
The study enrolled patients with chronic, refractory cough at U.S. and UK centers and randomized 63 to each of three active treatment arms receiving 7.5 mg, 20 mg, or 50 mg b.i.d. of MK-7264 or to placebo for 12 weeks. The patients averaged 60 years of age and about three-quarters were women. On average, they had their cough for more than 10 years, and these patients coughed roughly 30 times an hour when awake.
The study’s primary endpoint was reduction in awake cough frequency, and, after 12 weeks on treatment with 50 mg b.i.d., this had fallen an average of 37%, compared with placebo, said Dr. Smith, a professor of respiratory medicine at the University of Manchester, England.
The 7.5-mg and 20-mg b.i.d. dosages each led to cough frequency reductions of about 22% over placebo that were not statistically significant. This was likely a result of the unexpectedly strong placebo effect in the study, Dr. Smith said. Most of the cough effect was evident after the first 4 weeks on treatment.
Dr. Smith noted that she and her associates “most definitely” plan to progress to a phase III trial. “We really lack effective treatments for cough,” she said.
The study was sponsored by Merck, the company developing MK-7264. Dr. Smith is a consultant to Merck and has a licensing agreement with Vitalograph.
The video associated with this article is no longer available on this site. Please view all of our videos on the MDedge YouTube channel.
On Twitter @mitchelzoler