Clinical efficacy of raloxifene in postmenopausal women

A new class of compounds known as selective estrogen receptor modulators (SERMs) may possess the optimal combination of characteristics desirable in a drug designed for use in postmenopausal women. Among this class of compounds, raloxifene is the most studied and is currently available for clinical use in some countries for the prevention of osteoporosis in post-menopausal women. Raloxifene is a non-steroidal benzotiophene derivative shown to prevent bone loss at axial and appendicular sites and reduce serum cholesterol, like estrogen, in oophorectomized rats and in postmenopausal women. In animal models, unlike estrogen, raloxifene does not stimulate breast or uterine tissues. These appealing attributes make raloxifene a potential treatment for osteoporosis and other menopause related risks in middle aged and elderly women. Multicenter studies have been performed in early postmenopausal women, randomly assigned to receive raloxifene 30, 60, or 150 mg/day or placebo. All subjects received a calcium supplement. Bone mineral density, which was measured twice a year over 24 months by dual X-ray absorptiometry, decreased significantly at all skeletal sites with placebo, and significantly increased with raloxifene at the spine, hip, and total body at the three doses. At 24 months, the mean increase with raloxifene 60 mg compared with placebo was 2.4% at the lumbar spine and at the total hip, and 2% at the total body. Markers of bone formation (serum osteocalcin and bone specific alkaline phosphatase) and of resorption (urinary CrossLaps) decreased significantly to the premenopausal range within 3-6 months of treatment with raloxifene. In addition, total serum and low-density lipoprotein cholesterol decreased significantly in all raloxifene therapy groups in a dose-related fashion. Serum HDL-cholesterol and triglycerides were not significantly changed by therapy. The most commonly observed side-effect was hot flushes, with patients taking raloxifene reporting a slightly higher rate of flushes (25%) than those on placebo (18%). This adverse event usually occurred within the first few months of therapy, was generally mild, and did not result in excess study dropout (raloxifene 1.5%, placebo 2.1%). Preliminary 2-year data indicated that raloxifene is not associated with an increased risk of breast cancer. In summary, the clinical efficacy and safety of raloxifene is very promising and this compound will offer a particularly attractive choice for postmenopausal women.