WASHINGTON - Millions of women gained a new option to prevent crippling osteoporosis Wednesday: The government approved a drug that mimics estrogen's bone-saving effects but without the risk of breast cancer.
It does not protect bone quite as well as estrogen, prompting Food and Drug Administration advisers to dub it "estrogen light."
But the FDA said that raloxifene, the first so-called designer estrogen, works well enough to offer it to the estimated 10 million postmenopausal women at risk for the bone-thinning disease.
It is an option for women who are worried that long-term estrogen use can increase the risk of breast cancer, or who don't like the fact that the hormone can restart their menstrual periods, said Dr. Solomon Sobel, FDA's chief of endocrinologic drugs.
Eli Lilly & Co. will sell raloxifene under the brand name Evista. It will be on pharmacy shelves by early January.
The company would not say how much the drug will cost, other than to call it "competitive" with other osteoporosis treatments. Estrogen therapy costs about 50 cents a day and the non-hormonal alternative, Fosamax, costs about $1.80 a day, Lilly said.
Wyeth-Ayerst's estrogen therapy, called Premarin, is the nation's top-selling drug, with some $1 billion in annual sales.
Raloxifene isn't risk-free. It increases chances of serious blood clots by about the same amount as birth control pills do. Also, 4 percent of women suffered leg cramps in a study, and raloxifene did nothing for hot flashes.
Lilly is studying whether the drug can decrease the number of broken bones in women who already have osteoporosis, like estrogen and Fosamax can. For now, it is approved only to prevent, not treat, the disease.
Estrogen fights hot flashes and other menopausal symptoms, and protects bones as well as helping keep women's hearts healthy. Some studies suggest it may even help prevent Alzheimer's disease.
But only 20 percent of postmenopausal women who are considered candidates for estrogen take the hormone, because of the cancer fear and the menstrual effects. They can try other osteoporosis treatments, such as Fosamax and calcium, to protect only their bones.
Raloxifene offers another alternative. It works much as a key fits into a lock, slipping into estrogen receptors in the bone and perhaps - although not proven yet - the cardiovascular system to protect those tissues while blocking estrogen receptors in the breast.
"We do expect this is the first in a class of drugs which may prove to be very important," said FDA's Sobel, who expects future competitors in this category to have stronger effects.
Lilly studied some 13,000 women with moderately to severely brittle bones. Over two years, patients who took raloxifene saw a 2 percent increase in bone density, while those on placebo suffered a 1 percent loss.
Estrogen was better: a 3.8 percent bone gain.
But raloxifene did not increase the risk of breast cancer. In fact, patients had less than half the cases Lilly expected to see.
In addition, raloxifene and estrogen both decreased patients' "bad cholesterol," or low-density lipoproteins, by the same amount. That's encouraging, Sobel said, because this cholesterol increases the risk of heart disease. But he noted that raloxifene did not increase the "good cholesterol," or high-density lipoproteins, as estrogen does.
And Dr. William Andrews, past president of the American College of Obstetrics and Gynecology, said a monkey study about to be published found raloxifene does not have estrogen's beneficial effects on the heart's arteries.
"There are a certain number of women who are just frightened of estrogen, and this is an alternative for them," Andrews said. But "if she has a family history of heart problems, she's got to be given all the information."