By Rita Rubin
WebMD Health News
Reviewed by Arefa Cassoobhoy, MD, MPH
Oct. 20, 2014 -- The FDA has approved six brand-name drugs to help men get an erection. But it has yet to green-light a drug -- a "pink Viagra" -- to help women distressed about their lack of libido.
While critics say the FDA has a gender bias when it comes to treating sexual problems, the agency says it carefully weighs the risks and benefits of all drugs it approves. Some experts say female sexual dysfunction is more complex, making it harder to treat.
The topic will be front and center at an FDA meeting this month, one in a series of 20 looking at "patient-focused drug development."
The meeting on Oct. 27-28 will include statements from patients about the impact that female sexual dysfunction has had on their lives. It will also include a scientific workshop to discuss how to diagnose the disorder and measure how well medications for it work.
The charge that the FDA holds drugs to treat women's sexual problems to a higher standard than those for erectile dysfunction has divided women's and health organizations.
Even the Score is a campaign launched in June that's backed by the drug companies of at least three potential treatments for female sexual dysfunction. A petition to the FDA posted by Even the Score on change.org had more than 16,000 signatures as of Oct. 17. "We urge you to work fairly and urgently toward a solution to an unmet medical need..." the petition states.
Meanwhile, the National Women's Health Network and the American Medical Women's Association, among others, have supported the FDA's decisions not to approve a drug for female sexual dysfunction.
Cindy Pearson, executive director of the National Women's Health Network, says while the FDA has not been immune to gender bias, that's not at play here. "If it were gender bias, we would be yelling and screaming," Pearson says. "The problem is the drugs. Our biology is so much more complicated than men's."
Female sexual response includes not only libido, or desire, but arousal and orgasm, or satisfaction.
"Pfizer put a lot of money...into testing Viagra in women," Pearson says. "It just failed."
PharmedOut, a Georgetown University Medical Center project, notes in a fact sheet entitled "Don't need drugs to score" that the FDA has never approved any drug specifically to boost men's libido or any other male sex problem other than ED, which usually isn't related to a man's sex drive.
Rejected 'Pink Viagra' Drugs
A decade ago, Procter & Gamble sought the FDA's permission to market Intrinsa, a testosterone patch, for women who felt low sexual desire after having their ovaries removed. But the agency rejected the patch, saying it was only a little effective and could potentially raise women's risks of breast cancer and heart disease.
More recently, LibiGel, a testosterone gel intended to improve women's sex lives, was found to be no more effective in clinical trials than a placebo gel.
"The FDA made the right decisions on every single 'pink Viagra' drug they've reviewed and rejected," says Diana Zuckerman, PhD. She's president of the National Center for Health Research, a nonprofit education and advocacy organization. She's also a long-time FDA critic. "There's so much placebo effect going on here."
According to Endocrine Society guidelines, testosterone therapy should only be prescribed to women diagnosed as having no interest in sex, and that lack of interest causes distress -- a condition called hypoactive sexual desire disorder (HSDD). It should not be prescribed for women who don't have HSDD, since testosterone therapy has been linked to changes in cholesterol, along with acne and hair growth in places including the face, hair, and chest. Its long-term safety in women is unknown, the society says.
Flibanserin, the most recent potential female sexuality drug rejected by the FDA, was barely more effective than a placebo in clinical trials, Zuckerman says. "The tricky part with this is you really can't distinguish scientifically between the psychological and the physiological, because they're so intertwined," she says. If a woman isn't happy with her partner, she might not be able to become aroused, "but she gets a new partner, and her physiology just changes."
The three drug companies listed as supporters on the Even the Score web site have done clinical trials of drugs to treat women's sexual problems:
- Palatin Technologies, a New Jersey company, is developing bremelanotide, which you inject under the skin to treat FSD.
- Trimel Pharmaceuticals, a Toronto company, is testing Tefina, a nasal testosterone gel, to treat women distressed over their quality or lack of orgasms, a condition called "female orgasmic disorder."
- Sprout Pharmaceuticals, a North Carolina company, plans to resubmit its application to the FDA for approval of flibanserin in the first quarter of 2015, spokesman Geoff Curtis says. The company is now looking at data from two small studies the agency had requested: one on drug interactions and one on the effect on driving (since sedation was a side effect seen in clinical trials).
The FDA has twice rejected flibanserin, initially developed as a potential antidepressant for men and women. The first rejection of the drug, as a treatment for low libido in premenopausal women, came in 2010. An advisory committee ruled that it wasn't significantly better than a placebo and that its benefits didn't outweigh its side effects. Sprout did further studies of the drug and reapplied to the FDA, but it was unsuccessful.
FDA spokeswoman Stephanie Yao says the agency "is committed to supporting the development of therapies for medical conditions related to female sexual dysfunction," and "carefully weighs each drug in terms of its risks and benefits."
Yao says that includes the FDA approval of Osphena in February 2013. Osphena treats painful sex, a symptom of changes in and around the vagina that are linked to menopause.
Approval of other treatments can't come soon enough, says Sheryl Kingsberg, PhD. She's a professor of reproductive biology and psychiatry at Case Western Reserve University School of Medicine. Kingsberg appears in a video for Eventhescore.org.
She says that while some aspects of desire are cultural, interpersonal, and psychological, half of the women she treats are in good relationships that value sex but could benefit from a treatment aimed at physical causes of low libido. "I have nothing to offer that population of women."
Kingsberg has served as a consultant to Trimel and the maker of LibiGel. She's also one of two people on the scientific advisory board of Viveve, a California company that has developed a device to treat for "vaginal laxity" resulting from childbirth. The Viveve System is not on the U.S. market, but it's gotten regulatory approval in Canada, Europe, and Hong Kong.
Anita Clayton, MD, interim chair of psychiatry and neurobehavioral sciences at the University of Virginia Health System, says that the way the FDA evaluates treatments to improve women's sex drive is off-base. She prescribes Viagra to women with a low sex drive due to taking antidepressants. Simply counting how many times a woman had sex isn't an accurate measure, because women can have sex without having desire, she says. But if you increase the number of sexual encounters that are satisfying for them by even one a month, "women will say that's meaningful to them," Clayton says.
Both she and Kingsberg have enrolled patients in clinical trials of flibanserin, and Clayton has served as a consultant for Sprout.
Barbara Mintzes, PhD, isn't convinced. Mintzes, an associate professor in the School of Population and Public Health at the University of British Columbia, is the co-author of the book "Sex, Lies, and Pharmaceuticals: How Drug Companies Plan to Profit from Female Sexual Dysfunction."
"There is nothing sexist about ensuring that a drug is adequately effective and safe before approving it for marketing," Mintzes says. "Additionally, the whole question of what exactly we are treating, and the role of relationships [and] violence and other social factors contributing to sexual history, are left out of the picture."
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