Somaxon Pharmaceuticals, Inc., a specialty pharmaceutical company focused on developing and marketing products for the treatment of insomnia and other neuro-psychiatric disorders, has initiated patient enrolment in the first Phase III clinical trial of Silenor (doxepin HCl) for insomnia.

This multi-centre, placebo-controlled Phase III study will evaluate the safety and efficacy of Silenor in adults with primary, chronic insomnia. The primary endpoint of the study is a sleep maintenance measure, Wake After Sleep Onset (WASO) measured by polysomnography (PSG) in a sleep laboratory setting. Multiple secondary endpoints of sleep maintenance, onset and duration will be measured objectively and through patient reported outcomes.

Philip Jochelson, chief medical officer of Somaxon commented, "The product demonstrated encouraging results in our two Phase II dose-finding clinical trials, especially with respect to sleep duration and sleep maintenance. In addition to the primary assessment of sleep maintenance, statistically significant improvements in sleep efficiency were observed at hours seven and eight without demonstrating impairment in measures of next day residual sedation relative to placebo. In addition to this adult Phase III study we anticipate commencing a second Phase III trial later this year in an elderly population with insomnia."