Procter & Gamble has signed a co-promotion deal with Somaxon Pharmaceuticals to market the latter’s insomnia drug Silenor, which is scheduled for roll out in the US next month.

The companies are joining ranks to create a combined salesforce of 215 representatives to sell the drug, which has recently been approved for insomnia characterised by difficulty with sleep maintenance, throughout the US.

Under the agreement, which initially runs to December 2012, P&G’s salesforce will promote Silenor (doxepin) to targeted primary care and other high-prescribing physicians, while Somaxon will focus on specialists and other “top-decile physicians” who treat the condition.

P&G has also agreed to promote the drug to targeted pharmacies and provide additional managed care support services, and, in return, has gained first dibs on the negotiation for rights to develop and market Silenor for over-the-counter sales. 

Specific financial details were not revealed, but Somaxon said it will book all sales of Silenor, and will pay P&G fixed fees and royalties on US net sales. Each firm will cover the costs of operating their own salesforce, but Somaxon is responsible for all other costs regarding the drug’s commercialisation. 

“With the combined effort of both sales forces, we will target 35,000 of the highest prescribers of insomnia products as well as 25,000 pharmacies, which we believe will allow us to be highly competitive in the insomnia market,” noted Richard Pascoe, Somaxon’s president and chief executive, commenting on the partnership.

And it seems investors are also very excited by the deal; the news sparked a frenzied exchange of Somaxon stock that ended with a 22.3% surge in the latter’s share price yesterday.