July 26, 2006

Somaxon Pharmaceuticals announced that oral nalmefene hydrochloride, an opiate antagonist, demonstrated positive results in a pilot Phase II clinical trial for smoking cessation. In the single-center, randomized, placebo-controlled study in which 76 smokers were enrolled, patients in the nalmefene 40-mg group demonstrated numerically higher abstinence rates relative to the placebo group. Patients in the nalmefene 80-mg group did not consistently achieve abstinence rates that were numerically superior to placebo. The study was not powered to demonstrate statistical significance.

Nalmefene was generally well-tolerated, with an adverse event profile similar to that observed in studies previously conducted with nalmefene. The most commonly reported adverse events were insomnia and nausea. The adverse events tended to be transient in nature and largely resolved after the first week on the study drug. Elevation in liver enzymes was observed with a similar frequency in all groups.

Nalmefene, an opioid antagonist, is approved and has been used for over 10 years in the United States in an intravenous form for the reversal of opioid drug effects.