A 2b clinical trial reveals that refractory chronic cough can be eased with a P2X3 inhibitor.
The preliminary trial led by Jacky Smith, MB, ChB, PhD, from the University of Manchester in the United Kingdom provides hope to patients with refractory chronic cough.
“This drug blocks the neuronal activation and blocks the cough,” Dr. Smith said. Current drug studies have revealed that dextromethorphan, a cough suppressant, only decreases cough by nearly 12 percent. “We’re showing 30 percent or more. It’s an empty market – we really need some new drugs that work.”
The research team compared a placebo with MK-7264 in patients, who have been diagnosed with refractory chronic cough, from 46 regions in the United States and United Kingdom. Sixty-four participants from the 253 volunteers were allocated a 7.5 milligram dose of MK-7264 over a 12-week-period, 63 participants were allocated to a 20 milligram dose, 63 participants were allocated a 50 milligram dose and the final 63 participants were allocated to a placebo.
Seventy-six percent of the patients were female and the average age was 60 years.
The researchers utilized a VitaloJAK digital recording device to assess the cough frequency and a visual analog scale for the cough severity.
As the dose increased, the participants began to report dysgeusia, a salty, foul, metallic or rancid taste that lingers in the mouth. In the 50-milligram group, six patients stopped taking the drug due to the taste disorder.
Since the dose was fixed, it could not be altered, but in the real world the physician could freely make dose adjustments to mitigate the adverse effect.
The researchers were surprised that some of the participants in the placebo group reported a decrease in cough.
The authors noted the drug was effective even when it was being administered in lower doses.
“The data generated here provide an optimistic view that we may be able to address this problem for some fraction of the patients,” said, Sonye Danoff, MD, PhD, from Johns Hopkins Medicine. Even though cough is not a life-threatening system, it can still have a considerable impact on the quality of life for the patient.
She cautioned, “The safety and to some degree, tolerability may play a role in treatment.” This is not a definitive study, but a preliminary trial.
Pulmonary specialists do not typically discuss self-dose adjustments with their patients. “That’s a fairly unique paradigm for pulmonary medicine – perhaps in pain this kind of study is seen, but it’s unusual in pulmonary,” Danoff explained.