May 27, 2003

Roberta Friedman, PhD

May 27, 2003 (Santa Cruz, California) — A drug not yet approved by the U.S Food and Drug Administration promises to help people with chronic insomnia. Eszopiclone has beneficial effects on falling asleep, staying asleep, and quality of sleep.

All three measures showed statistically significant improvement compared with placebo ( P < .01) at every month of a six-month trial, which was described in a poster presentation at the 156th annual meeting of the American Psychiatric Association in San Francisco.

The lead investigator of the study, Andrew Krystal, MD, said in a telephone interview with Medscape that he was surprised the drug worked as well as it did. "The amazing thing is the medication helped every king of sleep problem," he said. Dr. Krystal is associate professor of psychiatry at Duke University in Durham, North Carolina.

Participants reported on their sleep and daytime abilities weekly, using telephone keypad entry. This system improved on the usual sleep logs, which patients may rush to fill in, said Dr. Krystal, as they wait in the office for their visit.

The six-month, placebo-controlled trial studied more than 700 people with chronic insomnia.

Dr. Krystal said the trial is unique in following insomniacs for six months or more. Other studies have halted at a few weeks. A prior study attempted to track long-term use of a sleep aid with placebo control but failed when too many people dropped out, he said.

Despite the long-term course of the current trial, Dr. Krystal said, more than half of participants completed their treatment. "Many people suffer for a long time" with insomnia, "yet there is no data beyond five weeks," he said, for any drug that is marketed for treating sleep disorders.

Of the 768 patients enrolled in the study, 573 received eszopiclone and 195 received a placebo. Sixty percent of those receiving the active drug completed the six-month course, while 56.6% of patients who received placebo completed testing. After six months, participants could take the active drug, as an open-label extension of the trial, for another six months. Some of the patients therefore took the drug for a year.

No adverse effects were seen, including serious signs of withdrawal once the agent was stopped. Dr. Krystal noted that some benzodiazepines and barbiturates can produce seizures when long-term use is abruptly halted. He did not yet have information about more subtle signs signaling withdrawal. But no tolerance developed during the trial, he said.

Commenting on the eszopiclone study, Mary Carskadon, PhD, told Medscape, "This compound appears to have shown good efficacy over a prolonged period for measures that are important to people with chronic insomnia." Tolerance and safety also appear appear to be good, she said.

Dr. Carskadon, from Brown University's Sleep Research Laboratory of Bradley Hospital, added that her only concern is about the size of the effects, and the potential for any interaction with other medications. "Lots of people who have insomnia have other illnesses and take other medications," Dr. Carskadon pointed out.

Eszopiclone acts on the GABA receptor complex, the target of benzodiazepines, but at a different site.

In a separate poster, another new drug, indiplon, also showed an effect on sleep. Indiplon is short acting, said study investigator Thomas Roth, PhD, from the Henry Ford Health System in Detroit, Michigan.

Indiplon improved sleep latency by polysomnography as well as self-report in a placebo-controlled trial. These were healthy young people without insomnia, however. Another poster reported that indiplon showed no interaction with alcohol.

"It is not for a person who wakes in the middle of the night," said Dr. Roth, who directs the sleep center at Henry Ford. He added that the maker is working onan extended release version to address this need.

The eszopiclone study was funded by Sepracor, and the indiplon studies were funded by Neurocrine Biosciences, Inc.

APA 156th Annual Meeting: Abstract NR445, presented May 20, 2003; abstracts NR173, NR846, presented May 22, 2003.

Reviewed by Gary D. Vogin, MD

Roberta Friedman, PhD, is a freelance writer for Medscape.

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