Vivus has signed up Auxilium Pharmaceuticals to sell its erectile dysfunction drug Stendra in the USA and Canada.

Stendra (avanafil) was given the green light by the US Food and Drug Administration in April 2012, but there has been no launch yet as Vivus has been seeking a partner. Now Auxilium says it expects to begin a commercial launch by the end of 2013, followed by promotional activities in early January 2014 .

The latter will be carried out by a 150-strong sales force "currently devoted to strategic targeting of urologists, endocrinologists and certain high-prescribing primary care physicians". Auxilium added it plans to "leverage digital media to reach a broader audience online" in support of the phosphodiesterase type 5 (PDE5) inhibitor.

Cashwise, Auxilium will pay Vivus a one-time fee of $30 million and could make an extra $15 million payment if the FDA approves the Stendra label to reflect a 15 minute or less onset of action efficacy claim. Vivus could also bank up to $255 million based on the achievement of certain sales targets, plus royalties.

The new partners said the market for ED treatments continues to grow, with US sales exceeding $2.9 billion in 2012. However, about one half of men being treated with currently available PDE5 inhibitors are dissatisfied with the results and tend to switch among the products "in pursuit of better efficacy or less side effects".

Adrian Adams, Auxilium's chief executive, said "we believe the unique features of Stendra including its dosing interval (30 minutes prior to sexual activity), ability to take with or without food, modest alcohol consumption requirements and a favourable side effect profile make it an exciting entrant into the category". He added that the drug "complements our current portfolio of testosterone replacement therapy and ED products".

Vivus investors are impressed and Simos Simeonidis, an analyst at Cowen & Co, wrote in an investor note that "we like the deal, we like the terms and we like the partner", especially given that "this drug had been approved in the US and collecting dust an a shelf for a while now". He added that "management's attention can now be exclusively directed to the Qsymia (phentermine/topiramate) effort", referring to Vivus' obesity drug for which the search for a partner continues.