(This story has been posted on The Wall Street Journal Online's Health Blog at http://blogs.wsj.com/health.)
By Christopher Weaver
Patients with severe insomnia taking a Merck experimental sleep drug drifted off faster and slept longer than those taking placebos in two clinical studies discussed at a Boston sleep conference today.
The drug, suvorexant, opens a new category of sleep drugs by blocking orexin, the brain's chemical emissaries that promote alertness. Merck says it plans to apply for FDA approval later this year.
Both of Merck's trials included more than 1,000 patients with insomnia. Patients whose sleep troubles were caused by other medical problems weren't included in the studies. The results were reported after three months of taking the drug or a placebo.
Those taking suvorexant reported falling asleep 25.7 minutes faster than usual, and sleeping an hour longer in one trial. Merck's researchers also observed patients in sleep labs and determined that patients taking the drug fell asleep 36 minutes faster than usual, while those taking placebos fell asleep 26.6 minutes faster.
The second trial also showed the drug helped people sleep longer, though people in that group who took it didn't fall asleep faster than patients taking placebos.
The findings were presented at the Sleep 2012, an annual meeting of sleep scientists and health providers.
The U.S. market for sleep drugs sagged to $1.85 billion in 2011, down about 8% from the prior year, according to IMS Health, a health-care-information company. The decline was driven by generic competition for key sleep drugs.
Suvorexant could offer a new option for patients with chronic insomnia who routinely need sleeping pills, Merck hopes. Other sleep drugs on the market, such as Ambien, keep patients asleep for about two thirds of the night, while suvorexant provides longer rest, Dr. Darryle Schoepp, Merck's vice president in charge of neuroscience, said in an interview last week.
For decades, a series of sleep drugs have focused on "shutting down the whole brain in maybe a less natural way," Schoepp said. So-called Gaba agonists, such as Ambien, Sonata and Lunesta, which are often prescribed to be taken as needed, have been shown to have side effects, including sleep walking, in a small fraction of patients.
Merck says patients who routinely need sleep aids will better tolerate suvorexant, which also performed well in a cohort of patients Merck followed for a full year. In contrast to older drugs, Schoepp said, Merck's research showed that patients taking suvorexant experienced normal sleep rhythm.
The study showed suvorexant's main side effects were headaches and morning drowsiness.
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