Somaxon Pharmaceuticals reported positive results from a Phase III trial evaluating Silenor™ (doxepin HCl) in elderly patients with chronic primary insomnia. Silenor demonstrated a statistically significant improvement compared to placebo in the primary endpoint of this trial, Wake After Sleep Onset as measured at night one, for both doses studied (1 mg: p=0.0053, 3 mg: p<0.0001). Statistical significance for this endpoint was also achieved at the end of the 12-week treatment period for both doses studied (1 mg: p=0.0330, 3 mg: p<0.0001).
With the conclusion of this clinical trial, Somaxon has completed six well-controlled clinical trials with Silenor for the treatment of insomnia, including four Phase III trials. In each of these clinical trials, Silenor demonstrated statistically significant results in the trial’s designated primary endpoint. These endpoints included measures of both sleep maintenance and sleep onset. The company anticipates filing an NDA with the FDA in the third quarter of 2007, assuming that the company’s preclinical studies for Silenor are successful and proceed as currently scheduled.
The trial enrolled 240 elderly subjects, and efficacy assessments evaluated both objective polysomnography and subjective measures of sleep. Subjective efficacy assessments were made both in the sleep laboratory and on an outpatient basis. Safety and efficacy were evaluated over a 12-week period.
Both doses of Silenor achieved statistical significance for objective measures of sleep maintenance in the sleep laboratory setting, and for subjective measures of sleep maintenance and sleep onset in the outpatient setting. Effects at week 12 were statistically significant and similar to those observed at night one.