Somaxon’s Silenor Could Launch In Early ’09 Pending Partnering Discussions
This article was originally published in The Pink Sheet Daily
Executive Summary
Somaxon submits an NDA for the insomnia medication, setting it up for potential FDA approval in December, firm tells "The Pink Sheet" DAILY.
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Somaxon Pharmaceuticals is targeting early 2009 for the launch of the insomnia drug Silenor (doxepin) after submitting an NDA to FDA Jan. 31, positioning it for approval in December. The company is seeking a commercial partner for the launch of Silenor, but plans to maintain co-commercialization rights for the specialty market, the firm told "The Pink Sheet" DAILY. "The completion and submission of our NDA for Silenor represents a significant milestone for Somaxon," the San Diego specialty pharma said. "We believe that the improvements in sleep onset, sleep maintenance and sleep duration and the favorable safety and tolerability profile demonstrated by our clinical development program are sufficient to support a determination by the FDA that Silenor can be approved for the treatment of insomnia." The company submitted the NDA for Silenor under the 505(b)(2) regulatory pathway, allowing the firm to rely on published safety and efficacy data for other formulations of doxepin already approved by FDA. Doxepin has been used for the treatment of depression and anxiety for more than 35 years; it was first marketed by Pfizer as Sinequan in 1969. However, dosing for those indications typically ranges from 75 mg to 300 mg per day, which can result in anticholinergic and next-day residual side effects. Somaxon is seeking dosing of Silenor at much lower 1 mg, 3 mg and 6 mg levels, well tolerated in patients. FDA has indicated that it will not recommend regulation of Silenor as a controlled substance, according to Somaxon. That could give the insomnia medication an advantage in a crowded market. Drugs such as Sanofi-Aventis' Ambien (zolpidem), available in a low cost generic, and Sepracor's Lunesta (eszopicline) are regulated as controlled substances, althoughTakeda's Rozerem (ramelteon) is not. Those drugs and 10 other sleep aids added new warnings to labeling last year about the risk of complex sleep-related behaviors, including sleep-driving and sleep-eating (1 (Also see "Sedative Hypnotic Class Labeling Warns Of Sleep-Driving And “Complex” Behaviors" - Pink Sheet, 14 Mar, 2007.)). Such complex behaviors have not been seen in clinical trials with Silenor, Somaxon maintained. The NDA includes data from four Phase III clinical trials conducted by Somaxon. The studies demonstrated significant improvements following treatment with Silenor versus placebo on endpoints such as Wake After Sleep Onset, Latency to Persistent Sleep and Total Sleep Time. The submission also includes data from genotoxicity, reproductive toxicology and 26-week transgenic mouse carcinogenicity studies, which were completed based on the recommendation of FDA. The agency's request led to a delay in the NDA filing. The company had projected a third quarter 2007 timeline for the submission, but changed the target to the first quarter 2008 after the agency said the results of the mouse toxicity study had to be submitted with the NDA (2 (Also see "Somaxon Pushes Back Insomnia Drug Silenor NDA Filing To Q1 2008" - Pink Sheet, 10 May, 2007.)). Somaxon still plans to submit results of a standard two-year carcinogenicity study as a post-approval commitment, the firm said. The two-year carcinogenicity study in rats was initiated in August 2007. -Jessica Merrill ([email protected]) |