Advisers to FDA consider controversial drug to boost female libido

The experimental drug flibanserin, made by Sprout Pharmaceuticals, is at the center of a regulatory controversy.
The experimental drug flibanserin, made by Sprout Pharmaceuticals, is at the center of a regulatory controversy.
Allen Breed/AP

Update 2:02 p.m.: FDA panel backs female libido pill, under safety conditions

Government health experts are backing the approval of an experimental drug intended to boost the female sex drive, but stress that it should carry safety restrictions to manage side effects including fatigue, low blood pressure and fainting.

The Food and Drug Administration panel voted 18-6 in favor of approving Sprout Pharmaceutical's daily pill, flibanserin, on the condition that the drugmaker develops a plan to limit its risks.

The positive recommendation is a major victory for a drug sometimes hailed as "female Viagra," but which has been plagued for years by concerns of lackluster effectiveness and safety issues. The FDA has rejected the drug twice since 2010. A similar panel of federal experts voted unanimously against the drug's approval five years ago.

Thursday's recommendation is non-binding but the FDA often follows the advice of its experts. The FDA is expected to make its decision on the drug in August.

The experts acknowledged that flibanserin's effect is not very strong, but noted that there is a need for FDA-approved treatments to treat women's sexual problems.

"These are very modest results," said Dr. Julia Heiman of the Kinsey Institute at Indiana University. "But on the other hand, even modest results can make a lot of difference when you're at a certain point in the clinical problem."

In general, women taking flibanserin reported between 0.5 and 1 extra sexually satisfying event per month than women taking placebo. They also scored higher on questionnaires measuring desire, while scoring lower on measures of stress.

Panelists raised concerns about several safety issues seen with flibanserin, including low blood pressure and fainting spells. Those problems increased when patients combined the drug with alcohol and some commonly-used medications, including antifungal drugs. Sprout only studied the drug's alcohol interaction in a small study of 25 patients, most of whom were men.

"To be clear we really know almost nothing about the actual clinical effects of using this product together with alcohol," said Dr. Tobias Gerhard of Rutgers University. "We have some indication that there is clearly a concern from very small studies."

Several panelists said the drug's label must make clear it should not be used with alcohol and several other classes of medications. The company should also educate prescribers about the risk and conduct follow-up studies, the experts said.

Flibanserin, which acts on serotonin and other brain chemicals, was originally studied by Boehringer Ingelheim as a depression treatment, but then repurposed as a libido pill after women reported higher levels of sexual satisfaction. The German conglomerate sold the drug in 2011 to Sprout, a Raleigh, North Carolina-based startup company.

-The Associated Press

8:01 a.m.: Advisers to FDA consider controversial drug to boost female libido

A committee of medical advisers meets Thursday to consider whether to recommend that the Food and Drug Administration approve the first drug that aims to boost a woman's libido.

The FDA has twice before rejected the drug, called flibanserin, after previous advisory panels concluded there were questions about its safety and insufficient evidence that the drug was effective for women with low sex drives.

Sprout Pharmaceuticals, which makes flibanserin, has submitted more research that the company hopes will finally convince the advisers and the agency the drug is ready for the market. The company's evidence includes a study it says shows women can safely drive after using the medication. One concern about the drug is that it can leave women drowsy the day after taking it, increasing the risks for accidents.

"The review of flibanserin ... represents a critical milestone for the millions of American women and couples who live with the distress of this life-impacting condition without a single approved medical treatment today," Cindy Whitehead, Sprout's CEO, said in a statement before the hearing began.

Flibanserin, which the company plans to sell under the brand name Addyi if approved, shifts the balance of three key brain chemicals, increasing dopamine and norepinephrine and decreasing serotonin.

The drug has long been the focus of an intense debate. The company and some advocacy groups, including the National Organization for Women and Even the Score, have suggested that the FDA is being sexist by holding the drug to a higher standard than drugs, such as Viagra and Cialis, for male sexual problems.

The FDA denies those charges. In documents posted online in advance of the hearing, Hylton Joffe, director of the FDA's Division of Bone, Reproductive and Urologic Products, said that such claims "are misleading and inaccurate."

"The FDA rejects claims of gender bias," Joffe wrote. "The FDA's regulatory decision for each product is based on an assessment of whether the benefits outweigh the risks, and does not take gender into consideration."

Many women's health advocates agree with the agency's caution and remain opposed to the drug despite the company's new research.

"No amount of slick marketing can get around the fact that at least so far drugs [like flibanserin] just don't work," says Cindy Pearson of the National Women's Health Network. "Nevertheless, pharmaceutical executives hype the prospect of a 'pink Viagra' because the potential market is estimated to exceed $2 billion annually."

In the documents released in advance of the hearing, FDA reviewers concluded that the drug could boost libido in some women and increase the number of satisfying sexual experiences, but noted those effects are "numerically small."

According to the briefing documents, three studies that compared flibanserin with a placebo found that women using the drug had a median of 0.5 or 1.0 more satisfying sexual events a month, depending on the study. The median number of satisfactory sexual experiences each month before the drug test was two or three.

Some women's health experts argue that the campaign for flibanserin is oversimplifying female sexuality. Many women who experience a waning libido don't see it as a problem, these experts say. Moreover, a low libido may be a symptom of fluctuating hormones or of a health problem that needs attention, they add.

Some worry there could be serious side effects from long-term daily use of a the drug. And in the briefing documents, FDA reviewers highlighted side effects, including fainting and the increased risk for accidents, especially if the women combine the drug with alcohol.

"This drug is a combination of powerful brain neuromodulators prescribed for chronic use, with effects only appearing (if at all) after several weeks. This is in dramatic contrast to drugs like Viagra that are taken on an as-needed basis," says Leonore Tiefer, a New York University psychologist.

The company acknowledges flibanserin can have side effects, but maintains those are relatively minor and that the drug could help many women.

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This story has been updated.