France’s Servier has unveiled more promising data on its first-in-class antidepressant Valdoxan, this time showing superior efficacy over Prozac.

The data, presented at the European Congress of Neuropsychopharmacology in Istanbul, involved a 515-patient trial which revealed that the antidepressant efficacy of Valdoxan (agomelatine) was significantly superior to that of Eli Lilly’s Prozac (fluoxetine). The results follow previous studies which have shown the drug’s superiority for major depressive disorder over a number of selective serotonin reuptake inhibitors and serotonin noradrenalin reuptake inhibitors, notably Wyeth's big-selling Effexor (venlafaxine).

Valdoxan acts as a melanotergic MT1and MT2 receptor agonist, as well as an antagonist at serotonin 5-HT2C receptors, so has a different mechanism of action to the aforementioned established drug classes and experts speaking at a media briefing in Istanbul also focused on its positive side-effect profile. It preserves sexual function, is weight neutral and offers a favourable tolerability profile, thus resulting in better adherence and remission in depressed patients, said Servier, adding that is easy to use, with one 25mg tablet taken at bedtime.

Philip Gorwood, professor of psychiatry at Sainte Anne Hospital in Paris, told reporters that compliance “is a big issue”, as one out of two patients stop treatment within a month due to adverse effects, and this coupled with a fast onset of action makes Valdoxan an important treatment. Goran Hajakof the University of Regensburg, Germany, also noted that agomelatine offers a major advance in management of depression through the restoration of circadian rhythms, saying that it "has sleep-promoting properties without being sedative".

Sidney Kennedy of the University of Toronto added that “despite the availability of a wide range of existing antidepressants, there are clear unmet needs” in the management of the condition. Noting that Valdoxan, “with its innovative mode of action, represents a totally new approach to the management of MDD”, he went on to say that “we have focused for many years on ‘more of the same’ in terms of slight refinements of previous agents”.

Valdoxan received European Union marketing authorisation in February this year and is now available in Germany, Argentina, Brazil, Russia and Ukraine for the treatment of adults with MDD.