Flibanserin: effectiveness appears to be limited.
Hypoactive sexual desire disorder (HSDD), also known as female sexual interest/arousal disorder, affects 10-40% of women.
HSDD is defined as "persistently or recurrently deficient (or absent) sexual fantasies and desire for sexual activity," accompanied by "marked distress and interpersonal difficulty" that does not stem from a non-sexual mental disorder, medication, relationship stress or another medical condition.
Flibanserin - dubbed the "female Viagra" - was approved last year by the Food and Drug Administration (FDA) in a high-profile decision that attracted attention from the public and health professionals alike.
Added to safety issues were concerns about the medicalization of women's sexuality. It was unclear whether the benefits were worth the risks, and questions were raised about the influence of the pharmaceutical lobby on FDA decisions.
Sprout Pharmaceuticals purchased the rights to flibanserin after the FDA originally rejected it. They aroused support, including helping to create and fund the "Even the Score" advocacy campaign. The campaign claimed that sexism had motivated the rejection, rather than scientific evidence.
Within 48 hours of FDA approval, Valeant Pharmaceuticals, of which Sprout was a division, purchased the rights to flibanserin for about $1 billion in cash.
Dr. Loes Jaspers, of the Erasmus University Medical Center in Rotterdam, the Netherlands, and coauthors carried out a meta-analysis of the records of clinical trials for 5,914 women.
Desired effects are limited, but side-effects are significant
The trials, five of which were published and three unpublished, investigated the efficacy and safety of the medication for treatment of HSDD.
The findings indicate that flibanserin results, on average, in a monthly increase in satisfaction of one half of one sexual event, but that it significantly increases dizziness, sleepiness, nausea and fatigue among women using it. The overall impression of the women surveyed was that the drug led to either minimal or no improvement.
The studies reviewed were randomized clinical trials, but the quality of evidence was considered as "very low," due to design limitations and the indirectness of evidence.
Moreover, the authors point out that the efficacy outcomes in the published results were more favorable than those in the unpublished studies.
They conclude that the benefits of flibanserin are marginal, especially when taking into account the adverse effects.
The team calls for future studies to include women from diverse populations, and especially those who already have other conditions or considerations, including surgical menopause, and women who are using other medications.
In a linked commentary, Dr. Steven Woloshin and Dr. Lisa M. Schwartz, of the Dartmouth Institute for Health Policy and Clinical Practice in Lebanon, NH, say:
"The flibanserin saga is unsatisfying. The FDA approved a marginally effective drug for a non-life-threatening condition in the face of substantial, and unnecessary, uncertainty about its dangers. Women with distressing sexual desire problems need good treatments. We all need a drug approval process that delivers good decisions based on adequate evidence."
Last year, an article from MNT investigated whether flibanserin will really help women.