Overview Shows Raloxifene Reduces Breast Cancer Incidence in Postmenopausal Women

CHICAGO—The selective estrogen-receptor modulator (SERM) raloxifene (Evista) can dramatically reduce the incidence of breast cancer in healthy postmenopausal women, V. Craig Jordan, PhD, DSc, said at the San Antonio Breast Cancer Symposium. The agent is currently FDA approved for the treatment of osteoporosis in postmenopausal women.

Dr. Jordan, director of the Lynn Sage Breast Cancer Research Program, Northwestern University, presented integrated data from nine multicenter, double-blind, placebo-controlled, randomized trials of raloxifene in more than 10,000 women with no history of breast cancer. The studies were conducted to show the drug’s efficacy in osteoporosis, and most of the women in these trials had osteoporosis.

The overview analysis with an average 40 months of follow-up showed that raloxifene reduced the overall incidence of new breast cancers by 54%. The incidence of invasive breast cancers was reduced by 64%, and estrogen-receptor (ER)-positive tumors were decreased by 70%. There was no decrease in ER-negative tumors.

The trials included 10,553 post-menopausal women aged 41 through 80 randomized to receive either placebo or raloxifene, 60 mg or 120 mg daily. The data represent approximately 16,908 patient-years cumulative exposure to raloxifene, and approximately 8,132 patient-years cumulative exposure to placebo.

The incidence rate of newly diagnosed breast cancers was 1.7 per 1,000 patient-years on raloxifene, compared with 3.7 per 1,000 patient-years on placebo (see Table). This translates into a relative risk of breast cancer of 0.46 for women receiving raloxifene, Dr. Jordan said, which corresponds to a 54% overall reduction in breast cancer incidence.