Abstract
Lasofoxifene, a new selective estrogen receptor modulator (SERM), was investigated to assess its efficacy and safety in the management of postmenopausal osteoporosis. A dose of 0.5 mg/day of lasofoxifene, given to postmenopausal women with osteoporosis, induced a reduction in vertebral fracture rates after 3 years and a reduction, after 5 years, of nonvertebral fractures, estrogen receptor-positive and invasive breast cancers, major coronary heart diseases and strokes. However, this dose was associated with significant side effects including venous thromboembolisms, pulmonary embolisms, leg cramps, hot flushes, uterine polyps, endometrial hypertrophy, arthralgia and vaginal candidiasis. Since no effect was evidenced on hip fractures, the risk-benefit ratio of this new medication, compared with previously marketed SERMs is, at best, uncertain.