Somaxon Pharmaceuticals, Inc. Initiates Phase III Clinical Trials of SILENOR™ in Patients with Insomnia

Product will be evaluated in adult and elderly patients with primary chronic insomnia and transient insomnia

Somaxon Pharmaceuticals, Inc., a specialty pharmaceutical company focused on developing and marketing products for the treatment of insomnia and other neuro-psychiatric disorders, today announced the initiation of patient enrollment in the first Phase III clinical trial of SILENOR™ (doxepin HCl) for insomnia. This multi-center, 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, MD, Chief Medical Officer of Somaxon commented, “We are excited about the initiation of the Phase III clinical trials of SILENOR™. 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.”

Ken Cohen, President and CEO of Somaxon commented, “We believe SILENOR™ offers the potential to provide patients suffering from insomnia and the physicians who treat them with a highly differentiated treatment option. In addition to its emerging clinical profile, SILENOR’s ™ active ingredient is not a Schedule IV controlled substance and its mechanism of action is different from all currently approved products for the treatment of insomnia. Our recently completed $65 Million financing will allow us to advance the SILENOR™ Phase III program through its next clinical milestones.”

Somaxon recently completed two randomized, double blind placebo-controlled dose-finding Phase II trials with SILENOR™, one in adults and one in elderly patients with primary sleep maintenance insomnia. In those trials, SILENOR™ produced statistically significant improvement in sleep maintenance measures such as WASO, sleep duration measures such as Total Sleep Time (TST), and sleep induction measures such as Latency to Sleep Onset (LSO).

About Somaxon
Headquartered in San Diego, Somaxon Pharmaceuticals is a specialty pharmaceutical company focused on developing and commercializing products for the treatment of insomnia and other neuro-psychiatric disorders. The company has several product candidates in development. The most advanced clinical program focuses on the evaluation of SILENOR™ (doxepin HCl) for the treatment of insomnia, a condition that, according to the National Sleep Foundation’s Sleep in America Poll, affects more than 70 million Americans. These problems tend to worsen with age. Two-thirds of adults aged 55-84 report experiencing sleep problems a few or more nights a week Phase III clinical trials of SILENOR™ for the treatment of insomnia commenced in the second quarter of 2005.

A Phase II clinical trial with oral nalmefene for the treatment of pathological gambling was completed by Somaxon’s strategic partner, BioTie Therapies Corp. in 2003. Somaxon intends to initiate a double-blind, randomized, multi-center Phase II/III clinical trial in 2005 for the use of oral nalmefene for the treatment of pathological gambling, a growing health concern that has been recognized in the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association since 1980. It is estimated that in North America there are approximately 3 million pathological gamblers according to the National Gambling Impact Study Report. Pathological gambling is designated as an Impulse Control Disorder (ICD) which also includes pyromania, kleptomania, and intermittent explosive disorder. Pathological gambling and other ICDs represent significant unmet medical needs, with no approved drug therapy to treat these disorders. The company also intends in 2005 to initiate a Phase II proof of principle study with oral nalmefene for the treatment of nicotine dependency.

The company also has in-licensed the worldwide rights to the use of acamprosate, a GABA-A agonist and NMDA antagonist, for the treatment of movement disorders and other conditions and has initiated product development work on this compound.

For more information, please contact Ken Cohen, President and CEO (858.509.3670) or visit the company’s web site at www.somaxon.com.

Somaxon cautions you that statements included in this press release that are not a description of historical facts may be forward-looking statements. The inclusion of forward-looking statements should not be regarded as a representation by Somaxon that any of its plans will be achieved. Actual results may differ materially from those set forth in this release due to the risks and uncertainties inherent in Somaxon’s business including, without limitation, statements about: the progress and timing of its clinical trials; difficulties or delays in development, testing, obtaining regulatory approval, producing and marketing its products; unexpected adverse side effects or inadequate therapeutic efficacy of its product candidates that could delay or prevent product development or commercialization, or that could result in recalls or product liability claims; the scope and validity of patent protection for its product candidates; competition from other pharmaceutical or biotechnology companies; and its ability to complete subsequent closings of the Series C preferred stock financing or obtain additional financing to support its operations. All forward-looking statements are qualified in their entirety by this cautionary statement and Somaxon undertakes no obligation to revise or update this news release to reflect events or circumstances after the date hereof.