Effects of bazedoxifene on BMD and bone turnover in postmenopausal women: 2-yr results of a randomized, double-blind, placebo-, and active-controlled study

Osteoporosis is an increasingly common health concern in postmenopausal women. In a 2-yr phase III study, bazedoxifene prevented bone loss, reduced bone turnover, and was well tolerated in early postmenopausal women with normal or low BMD. Introduction: Bazedoxifene is a novel selective estrogen receptor modulator that has increased BMD and bone strength in experimental models, without stimulating breast or uterus. This 24-mo, randomized, double-blind study assessed the efficacy and safety of three doses of bazedoxifene compared with placebo and raloxifene in the prevention of postmenopausal osteoporosis. Materials and Methods: Healthy postmenopausal women with a BMD T-score at the lumbar spine or femoral neck between -1.0 and -2.5 or clinical risk factors for osteoporosis were randomly assigned to one of five groups: bazedoxifene 10, 20, or 40 mg/d, placebo, or raloxifene 60 mg/d. All women received elemental calcium. Efficacy outcomes included changes from baseline through 24 mo in BMD of the lumbar spine, hip, femoral neck, and femoral trochanter and biomarkers of bone metabolism. Results: The intent-to-treat population included 1434 women (mean age, 58 yr; mean time from last menstrual period, It yr). All doses of bazedoxifene and raloxifene prevented bone loss, whereas in the placebo group, there was significant loss of BMD at all skeletal sites. Mean differences in percent change in lumbar spine BMD from baseline to 24 mo relative to placebo were 1.08 +/- 0.28%, 1.41 +/- 0.28%, 1.49 +/- 0.28%, and 1.49 +/- 0.28% for 10, 20, and 40 mg bazedoxifene and 60 mg raloxifene, respectively (p < 0.001 for all comparisons). Comparable BMD responses were observed at other body sites. Significant and comparable decreases in serum osteocalcin and C-telopeptide levels from baseline and relative to placebo with active treatment were observed as early as 3 mo and were sustained through study conclusion (p < 0.001). Overall incidences of adverse events, serious adverse events, and discontinuations caused by adverse events were similar between groups. The most common adverse events included headache, infection, arthralgia, pain, hot flush, and back pain. Conclusions: Treatment with bazedoxifene prevented bone loss and reduced bone turnover equally as well as raloxifene and was generally well tolerated in postmenopausal women with normal/low BMD.