Clinical Trial Data Questions Flibanserin ApprovalMar 11, 2016
A review of clinical trial data is raising questions about the approval of Flibanserin, a drug used to increase female libido. In an editorial accompanying a systematic review and meta-analysis of evidence published in JAMA Internal Medicine, Steven Woloshin, MD, and Lisa M. Schwartz, MD, both from the Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, New Hampshire, say the U.S. Food and Drug Administration (FDA) approved "a marginally effective drug for a non-life-threatening condition in the face of substantial - and unnecessary — uncertainty about its dangers,".
The FDA approved Flibanserin, also called the "pink pill", last year to treat hyposexual desire disorder in premenopausal women. The approval was controversial; some scientists say Sprout Pharmaceuticals aggressively lobbied for the drug even though scientific evidence was lacking. The authors of the editorial write, "While it is unclear how strongly politics influenced the decision, it is clear that the science was weak,".
The editorial cites a systematic review by Loes Jaspers, MD, from the Erasmus University Medical Center, Rotterdam, the Netherlands, and colleagues. Using data from five published and three unpublished studies that enrolled 5,914 women, the authors looked at mean differences for change in satisfying sexual events (SSEs) between women given 100 mg flibanserin and placebo. Findings showed that the drug was linked to one-half additional satisfying sexual event per month.
Coauthor Ellen T. M. Laan, PhD, from the Department of Sexology and Psychosomatic Obstetrics and Gynecology, Academic Medical Center, University of Amsterdam, the Netherlands told JAMA Internal Medicine "Women had, on average, 2.5 satisfying sexual events per before entering the study, and flibanserin added one half additional satisfying sexual experience per month," Meanwhile, the risks for certain side effects increased fourfold. Adverse events included sleepiness and dizziness.
The authors state that "the overall quality of the evidence for both efficacy and safety outcomes was very low," The most common adverse events included dizziness, somnolence, nausea and fatigue.
The authors emphasize that the most important question "concerns the clinical relevance of the statistically significant efficacy outcomes, particularly considering [adverse events] that could worsen with concurrent alcohol intake or CYP3A4 inhibitors, including oral contraceptives and fluconazole."