Can Intrinsa Be a Viagra for Women?


By Amy Tsao Pfizer's (PFE) Viagra, the first drug approved for male impotence, has pioneered a who huge new product category for the pharmaceutical industry. But will women be equally interested in drugs that enhance sexual performance?

The answer may soon be here. The pharmaceuticals division of Cincinnati-based consumer-products giant Procter & Gamble (PG) has applied to the Food & Drug Administration for approval of a testosterone skin patch for women's use. The product would be targeted at women who have had their ovaries removed and are distressed by their low level of sexual desire. An FDA panel will meet on Dec. 2 to review the drug.

MILD SIDE EFFECTS. If it passes muster, P&G's Intrinsa patch would be the first drug approved specifically to address women's sexual needs. The market has been slow to develop, probably because of societal taboos, as well women's more nuanced and complicated sexual desire, which makes it hard for drugmakers to come up with a pill. Doctors have used a range of other treatments for women, including various hormones, antidepressants, and male impotence drugs like Viagra, Bayer's (BAY) Levitra, and Cialis, made by Eli Lilly (LLY) and Icos (ICOS).

For some women, Intrinsa, could be a big improvement over those treatments. In studies over six months of surgically menopausal women, those who received a placebo said satisfying sexual activity increased by an average of 19%, vs. a 73% increase for Intrinsa patch users. In the placebo group, women had an average increase in satisfying sexual episodes of 0.5 per month, while those with patches had an average increase of 1.9 episodes per month.

P&G has completed two large trials of the patch in women who have had both ovaries removed. It's also studying the patch in naturally menopausal women who are also taking estrogen. The outfit says side effects associated with testosterone, such as unwanted facial hair and acne, have been mild enough that participants didn't quit the studies because of them.

BLOCKBUSTER POTENTIAL? Testosterone, a hormone associated with sex drive in both men and women, already has a track record in helping boost the desire for sex. For decades, men with low sex drives have been prescribed products comprising high levels of the hormone. Physicians, lacking approved alternatives, have often given female patients smaller doses of the testosterone products for men in hopes of boosting desire without side effects.

P&G's patch, which is licensed from Watson Pharmaceuticals (WPI), would probably help open up a new market if it wins FDA approval. "The P&G data are very exciting," says Irwin Goldstein, professor of urology and gynecology at the Institute for Sexual Medicine at Boston University's School of Medicine. "This is the equivalent to women of what Viagra was to men. For the first time, we can empower women who have sexual problems."

That may be, but will the product have the blockbuster potential of Viagra, which generated $1.9 billion in revenues for Pfizer in 2003? P&G won't offer revenue projections, but it's optimistic that Intrinsa will be a big seller.

OTHER FACTORS INVOLVED. "There's a large unmet need," says spokeswoman Mary Johnson, noting that P&G received priority review status from the FDA. P&G recently conducted a survey on female health, which found that of 30 million women who are naturally menopausal, 3 million are distressed by their lack of sexual desire. Some 20% of 25 million women who are surgically menopausal are distressed.

The combination of P&G's consumer-marketing muscle and the inherent demand for the product could make the market for female sex-disorder treatments a robust one, figures Steve Simes, chief executive of Lincolnshire (Ill.)-based biotech BioSante (BPA). "We think the market is worth billions of dollars," says Simes. "Women are waiting for the product." Complaints about sex drive are among the most common women make to doctors, he notes. BioSante is starting a Phase III trial of a testosterone gel, LibiGel, next year.

Sexual-health specialists are pleased to see a drug for boosting female sex drive on the cusp of approval. But they caution that the treatments are just a first step. Biologically, healthy sexual function is about "blood flow, nerves, and hormones," says Goldstein. And along with the biological component, cultural and motivational factors are all "equally valid and relevant," says Sheryl Kingsberg, clinical psychologist and associate professor of reproductive biology at Case Western Reserve School of Medicine.

HORMONE THERAPY WORRIES. Even P&G's Johnson cautions that testosterone won't be a cure-all, largely because the hormone's deficiency isn't always the entire explanation for a woman's disinterest in sex. Lack of desire can be due to a "combination of things that, if not addressed for a long time, could become a psychological issue as well," says Johnson, referring to nonbiological factors. "It's important to understand there's no magic bullet."

Other downsides exist. Drugs like Viagra increase blood flow to the genitals. As long as a man is aroused, such medication usually works at the appropriate moment. By contrast, testosterone therapy is systemic and needs to be applied over a period of weeks or months to have a noticeable effect.

That could be a hurdle for many women, who have been bombarded with confusing messages about how they should use hormone therapy. Two years ago, a large government-funded study of estrogen and progestin showed the hormones raised the risk of some cancers and had little protective benefit, as had long been assumed. Experts today don't recommend hormone therapy unless a woman suffers difficult menopause symptoms.

BIG PUSH NEEDED. In all of the Phase III studies submitted to the FDA, women were taking estrogen along with the testosterone patch. So an FDA approval of the product would almost certainly require that women also be on estrogen. "There were some concerns, but certainly the trial filled up anyway," says Case Western's Kingsberg, who was an investigator in P&G's Phase III studies of Intrinsa.

P&G says it plans to gather follow-up data for at least three years. The outfit is also in the midst of a late-stage trial for menopausal women who aren't taking any estrogen.

Believe it or not, Viagra wasn't an overnight success. It took several years for the medical establishment and patients to become comfortable with the drug. And millions of marketing dollars were needed to make it a household name with blockbuster sales. Intrinsa won't enjoy similar success without P&G's dedication and heavy marketing. But if the millions the company has already spent on studying the product are any indication, Intrinsa could soon be a hot topic at water coolers around the nation. Tsao is a reporter BusinessWeek Online in New York


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