Trial success for Pierre Fabre - Forest antidepressant levomilnacipran

Forest Laboratories and Pierre Fabre Medicament have got their development programme for antidepressant levomilnacipran back on track, after reporting positive results in their third phase III study of the drug.

The two companies suffered a setback early last year when their first phase III trial of levomilnacipran in 326 patients with major depressive disorder (MDD) failed to show a significant benefit over placebo. 

Last July however they presented positive results in a second, 724-patient phase III trial, and the latest trial now gives them a confirmatory study in 442 patients that will support a marketing application in the US later this year.

Adding to the dataset will be another fixed-dose phase III study which is due to generate results in the coming weeks.

In the latest trial, treatment with levomilnacipran significantly reduced depression symptoms in patients with MDD compared to placebo, as early as week one and at each subsequent visit as measured by the widely-used MADRS-CR scale.

The serotonin and noradrenaline reuptake inhibitor (SNRI) also showed a significant impact on secondary endpoints, including the Sheehan Disability Scale. Meanwhile the drug was generally well-tolerated, with 77 per cent of patients completing the treatment course.

Frédéric Duchesne, president of the pharma division at Pierre Fabre, said the results "confirm our strategy to make neuropsychiatry a major priority for our research and development in prescription drugs".

If approved, levomilnacipran will enter a crowded marketplace for unipolar depression that is expected to shrink $11.6bn in 2010 to $9.5bn in 2020, thanks to generic competition to some of the current crop of top-selling antidepressants, according to Decision Resources.

Forest's own Cipralex (escitalopram) brand loses US patent protection later this year, while generic competition is already affecting Pfizer's Effexor XR (venlafaxine) product. Another big seller - Eli Lilly and Boehringer Ingelheim's Cymbalta/Xeristar (duloxetine)- is also facing loss of patent protection within two years.

Decision Resources has estimated that levomilnacipran will capture a quarter of the treatment-resistant depression market - roughly 5 per cent of the total market for unipolar depression medicines - in 2020. That would equate to a little under $500m in annual sales.