Men have Viagra and other pills to fight sexual impotence. Now women might soon have something roughly equivalent.
Procter & Gamble will try today to persuade a federal advisory panel to recommend approval of the first drug to increase a woman's sex drive.
The company plans to tell the committee, which advises the Food and Drug Administration, that the drug Intrinsa increases the sexual desire of women and the frequency with which they have "satisfying" sex. Some experts say approval of Intrinsa would mark a new era in the handling of women's sexual problems.
"It's a big breakthrough in acknowledging there are medical aspects to sexual dysfunction in women," said Jennifer R. Berman, director of the Female Sexual Medicine Center at the University of California, Los Angeles.
But the FDA's staff questioned whether the benefits of Intrinsa were "clinically meaningful." In trials, women who used Intrinsa had an increase in the number of "satisfying episodes" of sex to five a month, from three. But women who received the placebo also had an increase — to four a month, from three. The definition of satisfying sex was left to the women.
In documents posted on the FDA Web site Wednesday along with the company's data from clinical trials, the agency's reviewers also said they had concerns about the long-term safety of the treatment, which consists of the hormone testosterone. Other hormone therapies, involving estrogen and progestin, were widely used in the past by women after menopause but were later found to raise the risk of heart attacks, strokes and breast cancer, they wrote. Yet Intrinsa has been studied for longer than a year only in a small number of women.
Intrinsa, which P&G developed with Watson Pharmaceuticals, involves a patch, worn on the abdomen, that delivers a steady stream of testosterone. While that hormone is usually associated with men, women also make lesser amounts of it and it helps stimulate sexual desire.
Women produce about half their testosterone in their ovaries, so Procter & Gamble is initially seeking FDA approval for Intrinsa as a treatment for women who have had their ovaries removed. It said that 17 to 30 percent of the 10 million women who have undergone such surgery have "hypoactive sexual desire disorder," meaning low sex drive that they find distressing.
But the company is also testing the drug in women who undergo natural menopause.
While Intrinsa is sometimes popularly called the "female Viagra," it is not really equivalent. Viagra deals with a physiological problem involved in arousal while Intrinsa is meant to restore desire.
"Desire was not the problem for men — erections were," said Dr. Sheryl A. Kingsberg, a psychologist at Case Western Reserve Medical School. "For women, desire really is the problem."