Promising new help against crippling osteoporosis, government advisers recommended approval Thursday of a drug that mimics estrogen’s bone-saving effects but without the breast cancer risk.
But the long-awaited raloxifene does not protect bones as well as estrogen, the gold-standard treatment, advisers to the Food and Drug Administration said Thursday.
“I’d like to refer to it as ‘estrogen light.’ It does the same thing as Premarin but not as well,” said Dr. Glenn Braunstein of Cedars-Sinai Medical Center in Los Angeles, referring to the top estrogen brand.
Doctors said that raloxifene could be an important option for women afraid of estrogen, because long-term use can increase the risk of breast cancer. Others simply won’t take it because it brings back their menstrual period, said Dr. Ethel Siris of Columbia University.
“I don’t think anybody thinks raloxifene is going to replace estrogen,” she said. “If I can give estrogen, I will, but it’s a lovely option … for a substantial number of women.”
The FDA advisers voted 8-4 to recommend approval of raloxifene, to be sold by Eli Lilly under the brand name Evista. The FDA is not bound by the advice of its panels but usually follows it.
Ten million women have osteoporosis, and millions more over age 50 have thinning bones that put them at risk for the disease. Every year, 300,000 of them break hips and 700,000 fracture vertebrae.
Their treatment choices are calcium, a nonhormonal drug called Fosamax that works modestly well but that some women can’t take or afford and estrogen.
Choosing estrogen is complicated. It fights hot flashes and other menopause symptoms and protects bones as well as helping keep women’s hearts healthy, important because heart disease is the No. 1 killer of women. It may even help prevent Alzheimer’s disease.
But only 20 percent of postmenopausal women considered candidates for estrogen take the hormone because of its side effects and the cancer risk.
Raloxifene seems to mimic estrogen’s good effects but not the bad.
Much as a key fits into a lock, raloxifene slips into estrogen receptors in the bone and - Eli Lilly contends but has not proved - in the cardiovascular system to protect those tissues. But it blocks estrogen receptors in the breast.
Lilly studied some 13,000 women with moderate to severe brittle bones. Over two years, raloxifene patients saw a 2 percent increase in bone density, while those on placebo suffered a 1 percent loss.
But estrogen was better. The FDA said in the best comparison, estrogen patients had a 3.8 percent bone gain.
Raloxifene patients also had no increased risk of breast cancer. In fact, they had less than half the cases Lilly expected to see.
But 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, and the raloxifene did nothing for hot flashes.
However, raloxifene patients had drops in cholesterol and other predictors of heart disease. The FDA panel cautioned that’s not proof of a protective effect. Lilly will study raloxifene’s heart effects in 10,000 women in hopes of selling the drug as an estrogen alternative.
Women’s advocates urge caution, saying doctors should not assume the heart protection will be proved - and that long-term safety is still a question. The FDA panel noted that two-year studies are not long enough to be sure a breast cancer risk would never appear.
It prevents osteoporosis but “women should not use raloxifene for any other reason,” said Cynthia Pearson of the National Women’s Health Network. She pointed to recent Lilly ads raising doubts about estrogen and urged the FDA to ensure that the company doesn’t illegally promote raloxifene.