Results of a Phase 2 study sponsored by Somnus Therapeutics Inc add further evidence supporting the efficacy and safety of a novel bedtime therapeutic that addresses a major underserved need of insomnia patients—maintaining sleep. SKP-1041, a modified-release formulation of zaleplon, is designed to accomplish this by reducing middle-of-the-night (MOTN) awakenings without interfering with natural sleep onset and early deep sleep. At all three doses tested, SKP-1041 significantly reduced time spent awake during the night compared to placebo, with no evidence of next-morning adverse cognitive effects.

The study (SOM201), conducted in 67 nonelderly (ages 24-64) adults with primary insomnia characterized by MOTN awakening, was a four-way, double-blind, placebo-controlled, double-dummy crossover evaluation of SKP-1041. In a sleep laboratory setting, subjects were randomly assigned to receive SKP-1041 at 10, 15, or 20 mg doses taken immediately before bedtime. Sleep-wake episodes were recorded by polysomnography for 8 hours after lights-out. Residual cognitive effects were measured within 1 hour of awakening using DSST and DST.

“In this study, we saw statistically significant reductions in the time spent awake during the night (WASO) for all three dosage strengths tested. For the 15 and 20 mg doses, there was a significant reduction in the number of middle-of-the-night awakenings during hours 3-7 of the 8-hour sleep period (NAASO3-7) as well as increased total sleep time for hours 3-7 (TST 3-7),” said study investigator Russell Rosenberg, PhD, CEO, NeuroTrials Research and the Atlanta School of Sleep Medicine. “Blood levels of zaleplon were measured over 8 hours and confirmed the release of active drug starting 2 hours after ingestion. This facilitates peak hypnotic efficacy during the hours when unwanted awakenings are most likely to occur. Using the Digit Symbol Substitution Test (DSST) and Digit Span Test (DST) to test for next-day effects on cognition, we saw no impairment compared to placebo at all three doses.”