Boehringer Sex Pill May Not Aid Women, FDA Staff Say
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. Photographer: JB Reed/Bloomberg
Boehringer Ingelheim GmbH’s sexual desire drug flibanserin may not be effective or safe, according to U.S. regulators weighing whether to approve the first pill designed to boost women’s libidos.
The drug “failed to demonstrate a statistically significant improvement” in sexual desire, Food and Drug Administration staff said in a review released today. It was also linked to appendicitis, depression and loss of consciousness. Side effects led about 15 percent of women to stop treatment with the drug, the review said.
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 norepinephrin.
“The evidence that I’d seen about flibanserin did not seem to suggest that it was very effective,” Kim Wallen, a professor of psychology and behavioral neuro-endocrinology at Emory University in Atlanta, said today in an interview. “This isn’t a good way to start an FDA hearing on approval of a drug.”
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. Outside advisers to the FDA are scheduled to meet June 18 to review the safety and efficacy of the drug.
‘Confident’ in Drug
“We’re glad that we have the opportunity to discuss the scientific data with FDA,” said Heike Specht, a spokeswoman for Ingelheim, Germany-based Boehringer. “We are confident in the development program and the clinical evidence supporting the efficacy and tolerability of flibanserin.”
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.
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.
“I certainly see people who are so troubled by the problem that I believe that they would accept that it’s a reasonably safe drug to try to get some relief,” Thorp said.
Testosterone Patch
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.
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.
Estimated $2 Billion
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.
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.
“Viagra-like” drugs haven’t shown much success in women, said Jeffrey Jensen, a professor of obstetrics and gynecology at Oregon Health & Science University, in a telephone interview.
“That’s wrapped up in a whole bunch of stuff, not just plumbing,” Jensen said. “Treating male sexual arousal disorder is basically just plumbing -- getting blood flow to that area.”
To contact the reporter on this story: Molly Peterson in Washington at mpeterson9@bloomberg.net
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