FDA in 1997 approved Evista to help prevent osteoporosis and in 1999 approved it to treat the disease. Tamoxifen, which blocks the production of oestrogen, is the only FDA-approved drug for reducing breast cancer risk, but it increases risk for uterine cancer and blood clots. Raloxifene, which also blocks oestrogen production, has been shown to be as effective as tamoxifen at reducing breast cancer risk, though it increases risk of hot flashes and other menopause-related symptoms.
In documents released Friday, FDA said Evista lowers the risk of invasive breast cancer in some patients. The agency also said it would ask the panel to weigh the drug's benefits against serious side effects, such as deep vein thrombosis, pulmonary embolism and possible fatal stroke. Evista proved effective in reducing the risk of breast cancer in postmenopausal women whose cancer is fuelled by oestrogen; however, there seemed to be no decrease in risk among patients whose cancer did not need oestrogen to grow, FDA reviewers said in the documents. They also said that studies have provided less evidence for the proposed use to reduce the risk of developing invasive breast cancer in postmenopausal women at high risk of developing the disease (Kaiser Daily Women's Health Policy Report, 7/23).
The FDA panel on Tuesday voted 8-6 to allow Lilly to state on Evista's label that it reduces breast cancer risk "in postmenopausal women with osteoporosis." The panel also voted 10-4 to allow the label to state that Evista reduces the "risk of invasive breast cancer in women at high risk for breast cancer" (Wall Street Journal, 7/25). Antonio Grillo-Lopez, a panel member and retired oncologist, said Evista "shows at least similar efficacy and perhaps a better safety profile" than tamoxifen.
Reviewers on the panel also said use of the drug should be weighed against potential risks such as blood clots and fatal stroke. One study on the drug found that 862 women must be treated for Evista for one year to prevent invasive breast cancer in one of the women, according to reviewers. "The number of patients needed to treat for some benefit is astounding," Ronald Richardson, a panel member and medical oncology consultant for the Mayo Clinicsaid (Richwine, Reuters, 7/24).
"Today is an especially good day for postmenopausal women," Gwen Krivi, vice president of Lilly Research Laboratories, said, adding, "If approved, Evista would be the first and only therapy available to address two leading health issues for postmenopausal women - osteoporosis and breast cancer" (Eli Lilly release, 7/24). The company said FDA is expected to rule on the drug in September (Reuters, 7/24). FDA generally follows the recommendations of the panel but is not required to do so, the AP/Forbes reports (AP/Forbes, 7/24).
