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.