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Boehringer's Sex-Drive Pill Isn't Beneficial, FDA Panel Says
Boehringer Ingelheim GmbH failed to win a U.S. panel’s backing for its sexual desire drug flibanserin, providing a setback for the first pill designed to boost women’s libidos.
The treatment doesn’t provide enough benefits to outweigh potential risks to women such as fainting, outside advisers to the Food and Drug Administration said in an 11-0 vote today in Gaithersburg, Maryland. While the FDA usually follows its advisory panels’ recommendations, it isn’t required to do so.
While male sexual enhancement treatments led by Pfizer Inc.’s Viagra facilitate erections by increasing blood flow to the penis, flibanserin is designed to work in the brain. Boehringer’s libido pill, first tested as an antidepressant, lowers the level of one brain chemical, serotonin, and boosts production of two others, dopamine and norepinephrine. The drug failed to demonstrate a “statistically significant improvement” in sexual desire in two U.S. trials, FDA staff said in a June 16 review of the drug.
“The efficacy was not sufficiently robust to justify the risks,” Julia Johnson, acting chairwoman of the advisory panel and chairwoman of obstetrics and gynecology at the University of Massachusetts Medical School in Worcester, Massachusetts, said after the vote. “There’s also relatively little data on long- term use.”
‘Unmet Need’
Boehringer, the world’s largest closely held drugmaker, asked the FDA to clear its pill to treat pre-menopausal women who suffer from hypoactive sexual desire disorder. Flibanserin targets a “widespread and unmet medical need,” said Sabine Luik, an executive at the Ingelheim, Germany-based company, in testimony at the FDA panel meeting today. Boehringer is aiming flibanserin as the first drug to heighten female desire.
The “totality of evidence” from research in the U.S. and Europe shows that flibanserin provides “clinically meaningful, statistically significant improvements” in HSDD symptoms, Michael Sand, Boehringer’s director of general medicine, told the panel today.
Hypoactive sexual desire disorder, defined as a drop in libido that causes problems in relationships, affects about 10 percent of women from the ages of 30 to 60, said John Thorp, a professor of obstetrics and gynecology at the University of North Carolina School of Medicine. It is typically treated with therapy and with prescriptions of male hormones such as testosterone, an unapproved use, he said.
Risk of Hormones
Taking male hormones can cause women to gain weight, grow facial hair, and face long-term health risks, said Thorp, who conducted Boehringer-sponsored studies of flibanserin.
The FDA may use a “very high safety threshold” in deciding whether to approve flibanserin because low sexual desire isn’t a life-threatening condition, Thorp said.
“Nobody’s going to die because their libido is low,” Thorp said. “The FDA is really going to have to be convinced about safety.”
Procter & Gamble Co. and Watson Pharmaceuticals Inc., developed the testosterone patch Intrinsa, which is sold in Europe for women whose uteruses have been removed. A U.S. version was put on hold in 2004 after an FDA advisory panel said the drug needed more study because existing research couldn’t rule out heart and breast cancer risks. Warner Chilcott Plc, based in Ardee, Ireland, obtained Intrinsa in its August 2009 purchase of Procter & Gamble’s global pharmaceuticals unit.
Clinical Trials
In clinical tests of 1,378 women in North America, 48 percent of patients who took flibanserin for six months reported improved desire, compared with 30 percent with a placebo, Boehringer reported at a May 18 meeting of the American College of Obstetricians and Gynecologists in San Francisco.
An FDA analysis of data showed that women treated with flibanserin increased “sexually satisfying events” by fewer than one per month when compared with women given a placebo, according to the agency’s staff report. The drug also was linked to depression, anxiety, fatigue and loss of consciousness. About 15 percent of women stopped treatment because of side effects, the agency said in its report.
The FDA probably will reject the drug because it’s not safe or effective enough, Leonore Tiefer, a clinical associate professor of psychiatry at New York University, told the panel during a public comment portion of the meeting. Boehringer has been marketing flibanserin by trying to persuade regulators and consumers that low sexual desire is a disease, she said.
‘Deceptive Argument’
“Boehringer has told American women that a drug like flibanserin gives them additional choices and enhances empowerment, but this is a deceptive argument,” Tiefer said. “Flibanserin is not a choice when it’s promoted by bad science and half truths and when self-diagnosis checklists are passed off as medical care.”
Wayne Shields, president of the Association of Reproductive Health Professionals, disagreed and urged the panel to back the drug.
Hypoactive sexual desire disorder “is a genuine condition, it’s not a marketing term,” Shields told the panel. “The data and research that we have examined indicate that while flibanserin is not appropriate for every woman, it provides a safe and effective option for some women experiencing HSDD.”
Female libido drugs may create an annual market of at least $2 billion, said Stephen Simes, chief executive officer of BioSante Pharmaceuticals Inc., in a June 9 presentation to investors. The Lincolnshire, Illinois-based company’s Libigel, a topical testosterone, is in the third and final stage of tests generally required for U.S. approval.
Drug Sales
Viagra had sales of $1.89 billion last year, including $962 million in the U.S., Pfizer said Feb. 3. Cialis generated $1.56 billion in sales last year for Eli Lilly & Co., including $623.3 million in the U.S., the Indianapolis-based company reported Jan. 28.
“The success of Viagra, which was phenomenal, has led to the desire to have a similar drug for women, and it’s just not going to be forthcoming because women’s sexuality is a lot more complicated,” said Susan Bennett, who teaches female sexual physiology at Harvard Medical School, in a telephone interview.
Companies will shy away from research in female desire drugs if Boehringer fails to win FDA approval for flibanserin, said Jeffrey Jensen, professor of obstetrics and gynecology at Oregon Health & Science University, in an interview. Women’s desire may simply be too complex to easily treat with a pill, he said.
“Do you have decreased desire because your partner’s a creep, or because you’ve been working all day long and all you want to do is go to sleep?” Jensen said. “Teasing out the intricacies of human behavior, desires, wants, and very private aspects of sexual behavior is very complicated.”
To contact the reporter on this story: Molly Peterson in Washington at mpeterson9@bloomberg.net
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