Boehringer Ingelheim's female libido booster, flibanserin, has left U.S. Food and Drug Administration reviewers cold, inviting agency concerns that the drug may be neither safe nor effective. The drug, first tested as an antidepressant, “failed to demonstrate a statistically significant improvement” in sexual desire, the agency says in its review.

 

A lack of sexual desire, dubbed hypoactive sexual desire disorder in clinical terms, is the most common sexual issue experienced by women, researchers say.

 

Boehringer believes that flibanserin modulates the stimulatory and inhibitory neurotransmitter systems in selective brain areas, potentially correcting an imbalance in these systems to support a healthy sexual response.

 

But reviewers were not convinced. They looked primarily at two randomized, double-blind, North American clinical trials that compared two doses of flibanserin to a placebo in premenopausal women with documented hypoactive sexual desire disorder.

 

The reviewers’ in their analysis of that data cited concerns about the efficacy of flibanserin versus a placebo and also expressed worries about potential side-effects of the drug, including depression, dizziness, appendicitis, and loss of consciousness. They also found that, because “there were many significant medical and medication exclusion criteria for the efficacy trials,” it wasn't clear that the safety and efficacy data would be generalizable to the target population for the drug.

 

The multi-billion market for Viagra and other medicines targetting men's libidos have led some analysts feminine libido-boosters could be worth as much as $2 billion annualy, but the reviewers' panning of flibanserin means Boehringer is unlikely to see a slice of that anytime soon.