Drug improves time to fall asleep and duration of sleep.
A drug that blocks the brain mechanisms that keep people awake appears to help those with primary insomnia fall asleep and stay asleep longer than placebo, researchers reported here at the annual meeting of the Associated Professional Sleep Societies.
In one study of long-term effects of a year’s use of suvorexant, insomnia patients taking the drug were able to sleep about an hour longer while patients on placebo were able to sleep less than 30 minutes longer than their baseline times, said W. Joseph Herring MD, PhD, senior director of clinical research in neuroscience and ophthalmology at Merck Research Laboratories in Whitehouse Station, N.J.
Herring also illustrated that after 12 months on the drug, insomniacs were able to get to sleep almost 30 minutes earlier than before they started the trial, while placebo patients reduced their time to sleep onset by about 15 minutes.
The long-term study was one of three trials that Herring and colleagues conducted on the drug and presented at the meeting. In the long-term trial, researchers assigned 521 patients with insomnia to suvorexant and 258 patients to placebo. The mean age of the patients was about 61 years, and about 55 percent were women.
Importantly, Herring said that the safety profile of the new drug, which inhibits orexin – the substance that helps keep people awake – did not appear to show any areas of concern.
“We did not see any meaningful weight changes observed over the year of treatment,” he said in his oral presentation. “We did not see evidence for emergent adverse events over time. There was no significant rebound by patient-reported measures upon discontinuation of suvorexant, and there were no clinically significant withdrawal symptoms.”
The researchers were especially focused on cataplexy events, but none occurred in any of the trials, he said.
Herring also presented short-term results showing safety and efficacy from two studies that were almost identical in format, with overlapping outcomes.
In a late-breaker presentation, Herring described the twin trials, P-028 and P-029. The trial tested two doses of suvorexant – a high dose of 40 mg in non-elderly patients and 30 mg for elderly individuals, and a low dose of 20 mg and 15 mg. In trial P028, researchers assigned 254 patients to the low dose and 383 patients to the higher dose; another 384 patients were given placebo.
In P029, the low dose was administered to 239 patients; 387 got the high dose and 383 were given placebo.
Herring said that treatment with suvorexant “improved sleep onset and maintenance over a three-month period in two pivotal trials. Suvorexant is generally safe and well-tolerated in non-elderly and elderly patients for up to 3 months of treatment without clinically important rebound or withdrawal.”
“This is a very exciting drug,” said Martin Scharf, PhD, head of the Tri-State Sleep Disorders Center, Cincinnati. Scharf told MedPage Today that he has worked in clinical trials of many sleep drugs, including zolpidem (Ambien) for which he was one of the principal investigators, and on suvorexant.
“All the drugs on the market now are designed to make you go to sleep; suvorexant targets the mechanism that keeps you awake,” he said. “We are always looking for new medications to treat people, and this looks like it will be helpful. We have gone from drugs that put people to sleep using total central nervous system depression to new drugs that target the mechanisms that make us sleep and keep us awake.”
By Ed Susman
APR