May 18 2005
Results from a Phase 3 clinical study presented at the 2005 Annual Scientific Meeting of the American Geriatrics Society showed that bedtime administration of ramelteon, an investigational compound currently under review for the treatment of insomnia, significantly reduced time to fall asleep in older adults with chronic insomnia. Additionally, no rebound insomnia or withdrawal effects were observed.
An estimated 60 million people in the U.S. suffer from insomnia, and approximately half of all older adults experience one or more symptoms of insomnia at least a few nights per week.
“Improving sleep in older adults is a very important health issue. Far too often, older adults and their physicians accept the myth that poor sleep is a fact of life – that it comes with aging,” said Thomas Roth, PhD, director of the Sleep Disorders and Research Center, Detroit, Mich. “Although it is true that as people age their sleep architecture changes, sleep by no means becomes less significant.”
A total of 829 older adults (ages 64–93 years) were enrolled in a randomized, double-blind, 5-week study. Participants received bedtime administration of one of three treatments: ramelteon 4 or 8 mg, or placebo. Study participants completed next-morning sleep questionnaires regarding their previous night’s sleep for each night during the study.
Analysis of data from the questionnaires showed that, in comparison to those who received placebo, study participants who received ramelteon 4 or 8 mg had statistically significant decreases in estimates of time to fall asleep. In addition, after patients discontinued the use of ramelteon, there was no rebound insomnia, nor did patients exhibit symptoms of withdrawal. The incidence of adverse events for both ramelteon 4 mg and 8 mg dose groups was comparable with that of placebo.
“We are extremely pleased with the results of this study. We think the data, which showed no rebound insomnia or withdrawal effects, are particularly exciting and may add to the potential for ramelteon to provide another option for older adults living with insomnia,” said Steve Sainati, MD, PhD, vice president of Clinical Research, Takeda Pharmaceuticals North America, Lincolnshire, Ill.
Ramelteon acts via a new mechanism of action, specifically targeting two receptors in the brain, MT1 and MT2 . The MT1 and MT2 receptors are located in the brain’s suprachiasmatic nuclei (SCN). The SCN is known as the body’s “master clock” because it regulates the 24-hour sleep-wake cycle. Together, it is believed the MT1 and MT2 receptors serve as key facilitators of sleep-wake regulation.
Currently prescribed sleep agents and some investigational drugs work by targeting gamma-aminobutyric acid (GABA) receptors, which are located throughout the brain. In pre-clinical studies, ramelteon has shown no affinity for GABA or opiate receptors.
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