Sex Drug Viagra Turns 10; Women Still Waiting

The quest for "pink Viagra" presses onward; can testosterone gel revive a woman's libido?

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It's Viagra's 10th birthday.

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Happy birthday, Viagra. Today marks a decade since Pfizer's lovechild was borne through the straits of regulatory approval. The little pill has helped millions of men reclaim their pride and their sex lives. It has also spawned progeny, in a sense, in the form of the erectile dysfunction drugs Levitra and Cialis. Men these days have little reason to let ED ruin a romp in the bedroom. Women, on the other hand, might not be as eager to celebrate. After 10 years of buzz about a Viagra-like drug for women, nothing has been approved to date. Two companies are racing to change that. Both have active, advanced research programs working on prospective female libido drugs, one of which is available now to women who qualify to join a clinical trial.

Illinois-based BioSante Pharmaceuticals has launched several late-stage studies of a testosterone gel intended to remedy libido loss after menopause. About 100 U.S. medical institutions are now on board to test the drug's safety and effectiveness among thousands of women; volunteers, some of whom will unknowingly receive a placebo, are still being recruited. Earlier trials found the gel useful in women bothered by low desire following medically needed surgery to remove their ovaries. (Those sex organs produce roughly half a woman's natural testosterone. Though often thought of as a "male hormone," testosterone is tied to libido in both sexes.) A dollop a day of the gel on their arm boosted the frequency of satisfying sexual events compared with a placebo.

An approved medication for low female libido may be in higher demand than Viagra ever was for men, says Stephen Simes, president and CEO of the company. His rationale: 1.4 million off-label testosterone prescriptions were written for women in 2006 alone. He forecasts the drug will be available by 2011, as long as no snags arise. (Women interested in enrolling in the trial can E-mail the company's investigators to see if they're eligible.)

A nonhormonal treatment is also on the horizon, with late-stage testing well underway. Boehringer Ingelheim's once-daily pill acts on serotonin receptors in the brain, which, after all, is the organ most heavily involved with sexual desire. Studies involve pre-menopausal women bothered by a low sex drive.

Too soon to tell. Still, excitement might be premature at this point, experts say. In 2004, a testosterone patch poised to be the first-ever treatment was denied approval by an FDA advisory committee. Long-term safety was a major worry. Procter & Gamble had demonstrated the patch's effectiveness with minimal side effects, but that couldn't shake concern that it might carry health risks down the line. After all, painkiller Vioxx had just been yanked off the market and the unforeseen ills of female hormone replacement therapy had recently surfaced.

"Before we approve a therapy that could be used by millions of women, I'd like to know that we're not going to hurt them, particularly when the benefit is modest," says Steven Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic, who was involved in deciding the patch's fate. "This is not a lack of sympathy for those who are unable to have a satisfying sexual relationship, but about balancing risks and benefits." The patch is approved in Europe.

One reason for the delay is that the FDA has set its approval standards high: A drug for women must not only elicit desire but also yield an increased number of sexually satisfying events. That's a requirement that Viagra never had to meet, says Anita Clayton, professor of psychiatry at the University of Virginia, and coauthor of Satisfaction: Women, Sex, and the Quest for Intimacy.

"I think the holdup is really our lack of understanding of female sexuality and applying this greater complexity to how we're studying potential treatments," says Clayton. "For women, a lot of our sexuality is above the neck, not below the waist," she says, which could explain why Viagra failed to produce results when tested in females. Viagra helps men with their most typical sexual problem—the inability to achieve and maintain an erection during sex—by causing blood to pool where it's needed. But female sex problems are more complicated and can be caused by a combination of hormonal, psychological, and interpersonal factors.