Phase III results reignite female sexual dysfunction controversy

Flibanserin "has the potential to help many women suffering from their lack of sexual desire," according to Professor Rossella Nappi, study investigator and Director of the Gynaecological Endocrinology & Menopause Unit at the Maugeri Foundation, Italy.

However, HSDD remains a controversial concept, with critics arguing that the diagnosis 'medicalises' and oversimplifies the complex issue of female sexuality.

As a 5HT_1A agonist, a 5HT_2A antagonist, and a partial agonist at dopamine D4 receptors, flibanserin is believed to target pathways in the brain that govern sexual response. It is being developed by Boehringer Ingelheim.

Phase III testing of the drug comprised four randomised, placebo-controlled 24-week trials, of which three (DAISY, VIOLET and DAHLIA) were conducted in North America and one (ORCHID) took place in Europe. All participants were in stable, monogamous, heterosexual relationships.

Pooled analysis of 1,378 women enrolled in the North American DAISY and VIOLET trials showed that flibanserin 100mg daily increased the frequency of satisfying sexual events by 1.7 per month. This improvement was significant compared with the increase of 1 per month obtained with placebo.

There were also significant improvements versus placebo in sexual desire and sexual functioning, and reductions in distress related to sexual dysfunction and low desire.

In the European trial, analysis of data from 634 women revealed improvements versus placebo in sexual desire and reductions in the two distress measures, all of which were significant. However, the increase in satisfying sexual events was not significant compared with placebo.

The adverse effects associated with flibanserin in the trials, including dizziness, nausea, fatigue and insomnia, were generally mild to moderate and transient, but led to discontinuation in approximately 15% of cases.