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New Sleeping Pill Suvorexant Works in Early Studies

Drug, Called Suvorexant, Helped People Fall Asleep Faster, Stay Asleep Longer

By Kathleen Doheny
WebMD Health News

Reviewed by Brunilda Nazario, MD

June 13, 2012 -- A new sleeping pill under study helps insomniacs fall asleep faster and stay asleep longer, according to new research.

The medicine, called suvorexant, is not available -- it has not yet been submitted to the FDA. Suvorexant works differently than other sleeping pills, says researcher Andrew D. Krystal, MD, a psychiatry professor at Duke University Medical Center. He reported the findings in Boston this week at Sleep 2012, the annual meeting of the Associated Professional Sleep Societies.

Suvorexant blocks chemical messengers in the brain known as orexins.

"The orexin system seems to be one of the most important, if not the most important, systems for inducing wakefulness,'' Krystal tells WebMD. "It seems to be the system that allows us to remain awake during the course of the day in a continuous chunk. We would fall asleep if it were not for the fact that orexin is being released in increasing amounts during the day."

Suvorexant's development is based on the relatively new idea that people with insomnia have too much activity in their orexin system when they are trying to go to sleep, says Krystal.

By decreasing the orexin activity, "you enhance sleep," says Krystal, who directs Duke's sleep research and insomnia programs.

Suvorexant has been through its phase III clinical trials, which gauge effectiveness and monitor side effects. In those trials, Krystal found the drug could shave off about half an hour of the time it took to fall asleep and add an hour, or more, of sleep time.

The development of almorexant, another drug that targets orexins, was dropped last year by GlaxoSmithKline and Actelion Ltd. for "tolerability" reasons, according to GlaxoSmithKline. Details on those tolerability issues have not been made public.

About Insomnia and Its Treatments

Insomnia affects about 30% of adults in a given year, according to the American Academy of Sleep Medicine. Up to 15% say they have chronic insomnia.

Insomniacs have trouble falling asleep, staying asleep, or both.

Sleeping pills are widely prescribed. In 2011, 63 million prescriptions for hypnotics (such as sleeping pills) and sedatives were dispensed in the U.S., according to the IMS Institute for Healthcare Informatics.

Other sleeping pills work in a variety of ways, such as binding with receptors in the brain that help control alertness or relaxation, or receptors that act on the body's body clock. Of course, there are plenty of other aspects to getting better sleep. Good sleep habits are a must. That includes going to bed at the same time each night, limiting caffeine, keeping TVs, computers, and smartphones out of the bedroom, and getting exercise (but not close to bedtime).

Suvorexant Studies

Suvorexant was tested in two studies that lasted three months and included about 2,000 adults. Krystal's team randomly assigned them to get suvorexant (in various doses) or a placebo.

The researchers studied objective measures gotten from the sleep lab and sleep tests. They also looked at subjective measures such as the patients' reports of the time it took to fall asleep and their total sleep time.

In both studies, patients taking suvorexant fell asleep faster and stayed asleep longer.

For instance, in one study, people on the sleeping pill at the three-month mark slept 60.3 minutes longer, on average, while those on placebo slept 40.6 minutes longer -- a difference of more than 19 minutes.

"Nineteen minutes a night of more sleep for an entire month is a lot of additional sleep," Krystal says.?

In the same study, those on suvorexant fell asleep about 25 minutes faster than at the start of the study; those on placebo fell asleep about 17 minutes faster.

Those on the pill spent about 48 minutes less time awake during the night than before the medication, compared to 25 fewer minutes for those on the placebo. For the second study, results were similar. "The fact [that] there is benefit on the sleep study finding and the self reporting finding is critical," Krystal says.

No serious adverse events were found in either trial. The most common complaints were sleepiness and headache. All of the studies were funded by Merck.

In third study, which lasted a year and was also presented at the meeting, 522 men and women were given suvorexant and 259 got a placebo.

The new sleeping pill improved the total sleep time as reported by the patient by an average of 23 minutes. It reduced the time it took to fall asleep by 10 minutes.

David Neubauer, MD, associate professor of psychiatry at Johns Hopkins Medical Institutions, who has researched almorexant, reviewed the findings for WebMD.

"I think so far the clinical trials are very encouraging and warrant further investigation," he says.

The new drug reflects a new view of sleep problems, says Neubauer. "The new thinking is that insomnia is not just trouble sleeping at night, but a 24-hour disorder for many people," he says. "For many people it is a kind of round-the-clock hyper arousal."

Neubauer has served on the advisory board for Purdue Pharma, which makes the sleep aid Intermezzo (zolpidem).

Krystal is a consultant to Merck. He has also consulted for, or done research for, other companies that make insomnia medications.

These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.

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SOURCES: Andrew D. Krystal, MD, professor of psychiatry and director, sleep research program and insomnia program, Duke University School of Medicine, Durham, N.C. Sleep Medicine 2012, 26th annual meeting, June 9-13, Boston. David Neubauer, MD, associate professor of psychiatry, Johns Hopkins Medical Institutions, Baltimore.

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