There are now two drugs approved for the prevention of breast cancer, after the U.S. Food and Drug Administration (FDA) last week approved raloxifene (Evista) to reduce the risk of invasive breast cancer in postmenopausal women at high risk of the disease. The new approval also covers raloxifene to reduce the risk of invasive breast cancer in postmenopausal women with osteoporosis.

Leading prevention researchers called the approval an important moment for women at high risk of breast cancer.

"I am excited that postmenopausal women at increased risk for breast cancer now have a choice of drugs to reduce their risk," says Dr. Leslie Ford, associate director for clinical research in NCI's Division of Cancer Prevention. "Women and their doctors are already familiar with raloxifene and should be comfortable using it for both breast cancer and osteoporosis prevention."

The agency's action follows recommendations in August by the FDA's Oncology Drugs Advisory Committee to approve the drug for both indications.

In a statement, Dr. Steven Galson, director of the FDA's Center for Drug Evaluation and Research, advised women at high risk of breast cancer to discuss raloxifene's risks and benefits with their physicians to determine "whether the drug is right for them."

Positive results from four different clinical trials formed the basis for the agency's approval of raloxifene, which was initially approved to prevent and treat osteoporosis in postmenopausal women.

Included among those was a pivotal, NCI-supported trial known as STAR, which demonstrated that raloxifene was as effective as tamoxifen - the first drug approved for breast cancer chemoprevention - at reducing breast cancer risk in postmenopausal women. In the trial, raloxifene was generally less toxic than tamoxifen, but it was not as effective at reducing the risk of a noninvasive condition that can be a precursor to cancer, known as ductal carcinoma in situ, or DCIS.

In the STAR trial, both raloxifene and tamoxifen reduced the risk of invasive breast cancer by approximately 50 percent. Women on raloxifene had a reduced risk of blood clots, endometrial cancer, and cataracts compared with women on tamoxifen, although not all were statistically significant reductions.