Female Libido Drug Gets Another Chance From the FDA


A drug designed to improve women’s sexual desire may gain approval from the Food and Drug Administration (FDA) despite being twice rejected. In response to an appeal by Sprout Pharmaceuticals, the small company that produces the drug, called flibanserin, the FDA has asked for different information, potentially paving the way for the drug to come to market in the future.

Though glibly being referred to by some media outlets as the “female Viagra,” flibanserin works much differently than the hugely popular erectile dysfunction drug. Originally developed as an anti-depressant, flibanserin works on brain chemistry—it boosts two neurotransmitters, dopamine and norepinephrine, that are associated with sexual excitement, and decreases serotonin, a neurotransmitter associated with sexual inhibition. The drug is intended for women who have Hypoactive Sexual Desire Disorder (HSDD), which is defined as a “stress-inducing loss of sex drive without an identifiable physical or psychological cause.” Put another way, it’s designed to increase libido and desire for sex. Unlike Viagra, which is taken in or near “the moment,” flibanserin is taken daily.

Studies have shown that flibanserin improves a women’s desire for sex and increases her number of satisfying sexual events. One manufacturer-sponsored randomized controlled trial found that it increased satisfying sexual events per month by an average of 2.5 events, compared with women taking the placebo, who only saw an average of 1.5 such events.

Perhaps more telling, however, are the first-hand reports from women who have tested the drug. Fifty-year-old Amanda Blackie told CBC News that she enrolled in the trial because, for reasons she could not identify, she was not interested in having sex with her fiancé. While on the medication, she said that she got sexually excited from simply talking to him on the phone. Cindy Whitehead, part of the husband-and-wife team that run Sprout Pharmaceuticals, told Bloomberg that women describe the change they experience on the drug as a sexual reawakening. “Women will say, we were out to dinner for date night and I couldn’t wait for the check to come,” she said. “Or, I was driving in the middle of a workday and I’ll want to send a sexy e-mail.”

The FDA has been unconvinced, however. In December, it rejected Sprout’s bid for approval, calling the drug’s impact modest and saying that the benefits did not outweigh the potential side effects of nausea, dizziness, and sleepiness. Many women’s health advocates were upset by this decision, noting that the FDA has approved 24 drugs designed to improve male sexual performance and not one for women. Moreover, they argued that this drug was being held to a much higher standard than those designed for men.

“The National Organization for Women has a long history of looking at the standards by which FDA approves drugs for women and there is clearly a bias here,” said the organization’s president, Terry O’Neill, in a press release. “When it comes to approving drugs for male sexual dysfunction, the FDA says yes with more limited research and serious side effects, but when it comes to women, their go-slow tactics are preventing us from having access to a treatment option where we make the decision in consultation with our healthcare provider.”

Sprout appealed the FDA’s decision, and in January a group of advocates met with the agency to express their concern about this potential double standard and the lack of any treatment for female sexual concern.

In response, the FDA has changed its ask of Sprout; rather than requesting a new Phase 3 trial of the drug’s impact, which would involve hundreds of subjects and could take a few years, it is asking the company for three smaller Phase 1 studies, in which it will enroll as few as 25 to 50 participants each to look at specific issues, including whether flibanserin impairs driving, how it interacts with other drugs, and how it’s metabolized in the liver.

Whitehead called this a “significant step toward the approval of flibanserin.”

The FDA would not comment on its decision, but in a statement to Bloomberg the agency said it “maintains the highest vigilance to protect and advance the health of women” and is “committed to helping companies develop safe and effective treatments for female sexual dysfunction.”

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