SAN DIEGO — Insomnnia may be the next big treatment regimen to make a switch from prescription-only to over the counter.
Somaxon Pharmaceuticals and partner Procter & Gamble on Monday revealed the two companies had sat down with the Food and Drug Administration to discuss clinical and regulatory guidance that Somaxon believes provides a clear path forward toward an OTC version of Silenor (doxepin).
The first patent for Silenor currently is set to expire in March 2013 — a prescription-only generic version of the medicine cannot be introduced prior to this. Silenor generated $6.2 million in prescription sales for the second quarter ended June 30, Somaxon reported.
Silenor is a tricyclic antidepressant that also is used as a hypnotic to initiate and maintain sleep. It was approved by the FDA for treatment of insomnia in March 2010. The point of differentiation for the insomnia population is that Silenor is not habit-forming. Abuse potential is a significant concern for people seeking sleep aids.
However, there will be a number of hurdles with any OTC switch attempt. Complex behaviors, such as "sleep-driving," are addressed within the prescribing information for the medicine, as is a potentiality for suicidal ideation. The active ingredient in Silenor — doxepin — works as an antidepressant at doses of between 10-times and 100-times the recommended dose of Silenor.
Somaxon believes that the FDA’s guidance provides an opportunity to develop an OTC label that is tailored to Silenor’s clinical profile and differentiated from other OTC sleep products. Somaxon believes that Silenor’s characteristics, including its lack of addiction potential and its clinical efficacy and safety profile, make it an ideal candidate to be the first prescription insomnia product to be converted to an OTC product.
“Our first year of marketing Silenor has provided us with a host of learnings relating to the market and the most efficient use of our resources to promote Silenor for the treatment of insomnia,” stated Richard Pascoe, Somaxon’s president and CEO. “The changes to the Procter & Gamble agreement [extending P&G's exclusive negotiation period relating to OTC rights to Silenor from 60 to 120 days] represent the natural evolution of our relationship at this stage in Silenor’s commercial growth, allowing us to reallocate resources from sales support toward Silenor consumer awareness initiatives, while continuing to explore the potential for a Silenor OTC life cycle management opportunity with a highly differentiated label."