WASHINGTON – The multidecade search for a pill that boosts sexual desire in women has hit another roadblock, raising questions about the future of efforts to develop a female equivalent to Viagra.
Sprout Pharmaceuticals said Wednesday that it has reached an impasse with the Food and Drug Administration over its drug, flibanserin. The daily pill is designed to increase libido in women by acting on brain chemicals linked to mood and appetite.
The FDA questions whether the drugs benefits outweigh its risks, considering its modest effectiveness and side effects including fatigue, dizziness and nausea.
Sprout said it is appealing an October letter from the FDA that denied approval and asked for more information. But chances for approval appear slim: Of the 17 appeals FDA considered last year, 14 were denied, according to government figures.
The agencys latest rejection raises serious questions for more than a half-dozen companies working to develop therapies for women who report stress due to lack of libido. Its a market that drugmakers have been trying to tap since the blockbuster success of Viagra, an erectile-dysfunction drug approved in the late 1990s to increase blood flow to the genitals.
But unlike sexual problems in men, most of womens sexual issues are psychological, not physical. As a result, there are a number of alternate causes that doctors must consider before diagnosing female sexual desire disorders, including relationship problems, hormone disorders, depression and mood issues caused by other medications.
Experts say that developing drugs for female sexual dysfunction is so difficult because of how poorly we understand the root causes.
Motivation is a hard thing to measure, said Emory University researcher Kim Wallen. Quite honestly, we dont know enough about what creates sexual motivation to manipulate it.