- Even after 12 months of treatment, zaleplon remained effective, did not cause withdrawal symptoms upon discontinuation -

LONDON, September 21, 1999 -- Results from a new clinical trial confirm that zaleplon is an effective, safe, and well tolerated medication for the long-term treatment (up to 12 months) of insomnia. Previous studies have proven the safety and tolerability of zaleplon for short-term use (up to four weeks) in the treatment of insomnia. The new study was presented here today at the annual meeting of the European College of Neuropsychopharmacology (ECNP).

Zaleplon received marketing authorization from the European Commission in May 1999 for the short-term treatment of insomnia in patients who have difficulty falling asleep.

"Because sleep medications may be addictive, it generally is advised not to use them for more than four weeks at a time," says Martin Scharf, Ph.D., Director of the Tri-State Sleep Disorders Center, and lead study investigator of one of the studies. "However, these data confirm that zaleplon is different from other sleep medications because it can be used safely for up to one year, without causing any withdrawal symptoms upon discontinuation."

Approximately one-third of the general population suffers from insomnia. Short-term or transient insomnia may be caused by many things, such as a change in sleeping or daily environments; a new home or job; jet lag; a new work schedule; pain from arthritis, headache, menstrual cramps, or backache; stress or anxiety; or use of certain medications. Chronic insomnia, or insomnia that lasts for more than one month, may be related to medical or behavioral problems.

"Treating chronic insomnia is very tricky, because the condition usually requires a longer treatment period than four weeks -- the maximum time for which most sleep medications can be used," says Dr. Scharf. "These data are encouraging, because they demonstrate that zaleplon is safe and well tolerated even if taken continuously for 12 months, and therefore may be a good option for people with chronic insomnia."

Clinical Trial Results
The study showed combined results from two 28-day, open-label trials of men and women, age 18 to 65, who suffer from insomnia. The first trial examined 242 patients, while the second trial included 42 subjects. In both trials, patients took 10 mg of zaleplon for up to 12 months.

For the duration of both studies, subjects completed daily questionnaires to assess time-to-sleep onset, total time slept, number of awakenings, and sleep quality. The incidence of withdrawal syndrome (a condition that often occurs after prolonged treatment with a sedative or hypnotic -- the category to which most sleep medications belong -- and may include hallucinations and seizures) was assessed with a withdrawal syndrome questionnaire.

Results from both trials show that zaleplon continued to work for up to 12 months, without causing withdrawal syndrome after discontinuation of treatment.

"It is very unusual for a sleep medication to maintain its potency during long-term treatment," says Dr. Scharf. "These results are remarkable, because they show that zaleplon continued to work for a full year without losing its effectiveness."

There were no serious long-term adverse events to zaleplon reported in either trial. The most common side effects reported were headache, rhinitis (inflammation of the nose), pharyngitis (inflammation of the throat), and infection. These side effects were also seen in double-blind studies of zaleplon, where tolerability has been similar to placebo.

Zaleplon is a non-benzodiazepine, the first in a new chemical class of drugs (pyrazolopyrimidine). It is under review by the U.S. Food and Drug Administration (FDA) for the treatment of insomnia in adults and elderly patients. Zaleplon has been shown to have a good tolerability and efficacy profile in helping people fall asleep quickly, while minimizing the next-day residual effects commonly associated with other sleep medications.