A letter from the FDA spells out the next steps Raleigh-based Sprout Pharmaceuticals must take to win approval of its female sexual desire drug – what has been called the female Vigara – and the company says he sees a path to winning that OK.
“We are encouraged by the FDA’s response and view it as a significant step toward the approval of flibanserin,” said Cindy Whitehead, president and chief operating officer of Sprout, in a statement.
“With data in over 11,000 patients to date, we are confident that further supporting the predictable risk/benefit profile of flibanserin will result in women having the first ever treatment for the most common form of female sexual dysfunction,” she added.
“We are committed to working closely with the Agency to finally provide premenopausal women affected by HSDD with a medical treatment option.”
HSDD stands for Hypoactive Sexual Desire Disorder.
If flibanserin gets the FDA’s OK, Sprout’s drug would become the first “female Viagra” drug approved for the market. Other companies that have tried to develop such products have either failed to win approval or have even failed to advance beyond clinical trials.
Boehringer Ingelheim, the German company that originally developed the compound, submitted a flibanserin drug application to the FDA in 2010. The agency declined to approve the drug, raising questions about its efficacy and safety. Sprout licensed the compound from Boehringer Ingelheim in 2011. The “female Viagra” name is an unofficial one associated with the the drug the first time it was going through the development and review process but it has no association with Pfizer’s Viagra, nor it work by the same mechanism of action.
Flibanserin was developed to treat hypoactive sexual desire disorder in pre-menopausal women. HSDD is a condition characterized by diminished sexual desire. Sprout recently published positive phase III clinical trial results in the Journal of Sexual Medicine showing that flibanserin performed better than a placebo. The most frequently reported adverse events were drowsiness, dizziness and nausea.
The daily pill is designed to increase libido in women by acting on brain chemicals linked to mood and appetite.
Next Steps
The FDA had stalled the approval process in December and spelled out in the new response what Sprout must do before its New Drug Application can be resubmitted.
The agency told Sprout to conduct two additional Phase 1 drug interaction studies plus a Phase 1 study focused on driver simulation. The FDA wants to see if there is possible driver impairment for women who take the once-daily drug.
The studies would include 25 to 50 healthy volunteers in each, according to Sprout.
HSDD is “defined as a persistent or recurrent deficiency or absence of sexual fantasies and desire for sexual activity that causes marked distress or interpersonal difficulty, and which is not better accounted for by a medical, substance-related, psychiatric (e.g., depression) or other sexual condition,” according to Sprout.
The FDA has questions whether the drug’s benefits outweigh its risks, considering its “modest” effectiveness and side effects including fatigue, dizziness and nausea.
Sprout had said in December it was appealing an October letter from the FDA that denied approval and asked for more information. But chances for approval appeared slim at the time: Of the 17 appeals FDA considered last year, 14 were denied, according to government figures.
The agency’s 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. It’s a market 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 women’s sexual issues are psychological, not physical. As a result, there are a number of alternate causes 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.
“Erectile dysfunction is a really easy thing to measure,” says Emory University researcher Kim Wallen. “Motivation is a hard thing to measure and, quite honestly, we don’t know enough about what creates sexual motivation to manipulate it.”
(The Associated Press contributed to this report.)
Editor’s note: Capitol Broadcasting is an investor in Sprot Pharmaceuticals.
