Shares in Vivus were on the rise yesterday as investors welcomed news that its erectile dysfunction (ED) drug Spedra has won European approval.

Spedra (avanafil), a PDE5 inhibitor like Pfizer's Viagra (sildenafil), Eli Lilly's Cialis (tadalafil) and Bayer's Levitra (vardenafil), is the first new chemical entity approved to treat ED in more that ten years, and the firm will be hoping for a significant slice of a market that is worth around $5.5 billion a year.

The drug's green light came on the back of clinical data showing that, in men with ED, erections sufficient for penetration were achieved in 77% of those taking Spedra compared with 54% in the placebo arm.

And crucially, the firm recently unveiled data showing that, across all Phase III studies, successful intercourse was observed in some patients taking Spedra as early as 15 minutes after dosing.

This could give the drug a significant edge over its rivals, as patients taking current PDE5 inhibitors must wait one to two hours before having sex or take medication daily.

Spedra won US approval more than a year ago but has not yet been launched as Vivus is still seeking a partner to help it market and sell the drug. 

Proxy fight

Its additional approval in Europe is good news for Vivus management, which is facing pressure from shareholders disappointed with the launch of the obesity drug Qsymia (phentermine/topiramate).

First Manhattan Company (FMC), Vivus' largest shareholder, is currently embroiled in a proxy fight with the firm, spurred by devastatingly low sales of Qsymia following its launch last September, which it is blaming on management.

In a filing to the US Securities and Exchange Commission, the FMC said the current management "lacks critical expertise and experience to successfully commercialise Qsymia", and that if its nominees are elected to Vivus' board it will seek to replace its chief executive.