By Michael Barbaro
Washington Post Staff Writer
Saturday, October 11, 2003; Page E01

The Food and Drug Administration yesterday approved Novavax Inc.'s new treatment for hot flashes and night sweats, adding the first lotion to a market for hormone replacement therapy now dominated by prescription pills and patches.

Federal regulators found that the drug, called Estrasorb, effectively treates the nagging symptoms of menopause, which afflict an estimated 80 percent of women at some point. The lotion, which contains the female hormone estrogen, is applied daily to the legs, thighs or calves. It works by replacing the hormones lost during menopause.

Biotechnology analysts believe Estrasorb may eventually find a $200 million annual niche in a $1.6 billion estrogen-therapy market. The target consumer: women who are tired of taking pills and uncomfortable with skin patches.

Estrasorb, which will be co-marketed with King Pharmaceuticals Inc. of Bristol, Tenn., is absorbed directly into the bloodstream through the skin. "This is a complex delivery system that has been validated by the FDA," Novavax chief executive Nelson M. Sims said. "There is a good reason to believe any hormone would work in this technology."

Despite Estrasorb's novel drug-delivery system, the treatment faces a number of barriers to widespread use. There are already three competitors on the market in the United States: pills, patches and vaginal rings, which are inserted into the vagina and release hormones. Analysts estimate that more than 80 percent of women who take estrogen therapies rely on a pill, meaning Novavax will compete most strongly against its alternatives, most likely the patch.

Ken Trbovich, an analyst at C.E. Unterberg, Towbin, a brokerage firm, thinks Estrasorb has a good shot at stealing customers from the patch. "The patch can fall off and irritates the skin," he said. "Plus, with a lotion, you don't have that constant reminder on your body that you are being treated for menopause."

Sims agrees that Estrasorb's most obvious market is women who use patches. "But we think we can be competitive in the oral market too," he said in an interview yesterday.

Officials at Novavax, based in Columbia, would not say how much the product will cost, except that the company will offer the treatment at a "premium" price. Analysts expect the treatment will cost about $40 a month, slightly more than most estrogen therapies.

Perhaps Novavax's greatest challenge is the perception that hormone replacement therapy is hazardous to a woman's health. The Women's Health Initiative, a research program of the National Institutes of Health, found that, when used as a long-term treatment, Prempro, a popular combination of the hormones estrogen and progestin, causes small increases in the rates of breast cancer, heart attacks, strokes and blood clots, outweighing any benefits.

The Women's Health Initiative study made no such claims about short-term, estrogen-only treatments.

Novavax says it will market Estrasorb as a short-term, estrogen-only remedy for hot flashes and night sweats. "Short-term use of these products has not shown the detrimental effects that long-term use of estrogen and progestin has shown," said D. Craig Wright, Novavax's chief scientific officer.

But women remain anxious about all types of hormone replacement therapies, and that concern has significantly dragged down sales of all products, according to data provided by C.E. Unterberg, Towbin. Among estrogen-only therapies, for example, sales of pills have fallen 34 percent and sales of patches have fallen by 15 percent since the Women's Health Initiative data were released in July 2002, the firm reported.

"When you say estrogen therapy, the red flags are waved. Women are still somewhat hesitant to use these treatments," said Julie Elder, a doctor who specializes in women's health at the Cleveland Clinic Foundation.

Novavax officials said there is another difference between Estrasorb and the hormone therapy used in the government-backed study. Estrasorb contains a naturally occurring form of estrogen, 17-beta estradiol, rather than the horse-derived form used in Prempro, which is made by Wyeth Pharmaceuticals.

The FDA said hormonal therapy products should be used for the shortest amount of time possible. The agency did not specify how long Estrasorb should be used.

Even in the wake of the Women's Health Initiative news, gynecologists say there is room for a new hormone replacement therapy. "There is definitely still a need for estrogen therapy for hot flashes," said Jan L. Shifren, a gynecologist at Massachusetts General Hospital and an assistant professor at Harvard Medical School. Hot flashes, she said, can keep women awake at night and sideline them during the day. "The reality is that they can be very disruptive."

For Novavax, the FDA approval ends a nine-year effort to commercialize Estrasorb, the first drug developed in-house to reach the market. Most analysts predicted approval in 2002, but the company yanked Estrasorb from consideration in April after regulators raised questions about the chemistry and manufacturing section of the drug's application.

Investors had expected the news for months. Novavax's shares closed at $7.63, down 37 cents.