01:00 AM EDT on Sunday, August 14, 2005

BY MELISSA HEALY
Los Angeles Times

In 1998, an eagerly anticipated pill to restore men's sexual performance -- Viagra -- took six months to win marketing approval from the U.S. Food and Drug Administration. But more than a year after its maker applied for the FDA's blessing, a medication shown to recharge the stalled sex drive of some women is riding a rockier road to approval.

Known as the Intrinsa patch, the product is designed to deliver small doses of testosterone through a woman's skin, boosting the level of the male sex hormone in her bloodstream. All women produce testosterone. But most women's testosterone levels decline with age, and surgical removal of the ovaries will cause a precipitous drop-off.

The frequent result is a condition known in medical circles as hypoactive sexual desire disorder, or HSDD. The dysfunction was not formally recognized in medicine until 1999, although by some estimates the condition affects about 11 million American women.

Women's sexuality is complex, affected more deeply than men's sex drive by mood, self-esteem and relationship issues. It has never been an easy thing to capture -- or to fix when it goes awry. It took years for the FDA and experts to devise ways to measure improvements in a woman's libido, and many still argue that counting "satisfying sexual events" is a gauge better suited to men than women.

Now, with concern mounting over the long-term safety of new drugs, the safety of women's testosterone use has become a new obstacle. Proponents of the patch, which include hysterectomy support groups and many gynecologists, say the timing of the product's FDA review could not have been worse.

Last December, just weeks after the arthritis drug Vioxx was pulled from the market for safety concerns, an FDA panel gave the testosterone patch -- made by Procter & Gamble -- the equivalent of a blinking red light.

THE PANEL RECOMMENDED against approval until the safety of long-term use was better tested and understood, and members suggested that nothing short of a five-year study involving thousands of women could allay their concerns. Acknowledging the "huge demand" that would probably come with approval, panel members voiced concerns that long-term use by millions of women might increase the rates of breast cancer, heart disease and stroke.

In the years after hormone replacement therapy came into wide use, those illnesses saw a significant uptick -- a trend that was not recognized until 2004. Then, a study that had followed thousands of women for five years revealed the risks of boosting estrogen and progestin levels as a treatment for menopausal symptoms. The scientific about-face that followed was difficult for many physicians and their patients, who are wary of reliving the experience with testosterone.

The recommendation by the FDA's panel of advisers was a major blow to the makers of Intrinsa. But with several clinical trials under way, Procter & Gamble Pharma and Personal Health hopes the FDA will consider approval anyway.

Two new studies in recent months have reignited debate about Intrinsa, a product once hailed as "the female Viagra." A study published earlier this month in the Archives of Internal Medicine -- conducted by Dr. Glenn D. Braunstein of Cedars-Sinai Medical Center in Los Angeles -- found that women who used the patch for 24 weeks reported, on average, a 67 percent increase in their sexual desire, compared with a 48 percent increase in desire reported by women taking a placebo, or dummy pill.

It also boosted the number of "satisfying sexual encounters" from an average of three per month to five -- slightly higher than the increase reported by women taking the placebo. A similar finding was reported in May by researchers at Baylor Medical College in Texas.