A post hoc exploratory analysis was conducted to examine correlations between changes in bone density, bone markers, and hot flushes after the treatment of postmenopausal women with bazedoxifene (BZA)/conjugated estrogens (CE).
In a 2-year phase 3 study, 3,397 postmenopausal women were randomized to BZA 10 mg/CE 0.45 mg, BZA 20 mg/CE 0.45 mg, BZA 40 mg/CE 0.45 mg, BZA 10 mg/CE 0.625 mg, BZA 20 mg/CE 0.625 mg, BZA 40 mg/CE 0.625 mg, raloxifene 60 mg, or placebo. In this analysis, bone density changes at 2 years were compared with baseline levels of the bone markers serum C-telopeptide and osteocalcin. Correlations between changes in bone density and changes in 12-week hot flush composite scores in symptomatic women were also analyzed.
Treatment with BZA 20 mg/CE 0.45 mg or BZA 20 mg/CE 0.625 mg increased lumbar spine bone density more in women with higher bone resorption and formation, categorized by baseline levels of C-telopeptide and osteocalcin (P < 0.001, both BZA/CE doses). With placebo, larger decreases in lumbar spine bone density were seen in the highest tertile of serum C-telopeptide. There was no correlation between changes in total hip bone density and baseline bone markers. There were significant correlations between percent change in hot flush score at week 12 and percent changes in lumbar spine (r = −0.31, P = 0.006) and total hip (r = −0.23, P = 0.044) bone densities at month 24.
With 2-year BZA/CE treatment, women with larger increases in lumbar spine and total hip densities also have higher baseline bone markers. Early reductions in hot flush score (12 wk) are predictive of long-term increases in bone density (24 mo).