Objectives. Alendronate and raloxifene are antiresorptive agents with different mechanisms of action, each used to treat osteoporosis in postmenopausal women. This study was undertaken to compare the efficacy and tolerability of alendronate to raloxifene in postmenopausal women with low-bone density.
Design. Randomized, double-masked, double-dummy multicentre international study.
Setting. Clinical trial centres in Europe, South America and Asia-Pacific.
Subjects. A total of 487 postmenopausal women with low bone density, based on bone mineral density (BMD) of the lumbar spine or hip (T-score ≤−2.0).
Interventions. Patients received either alendronate 70 mg once weekly and daily placebo identical to raloxifene or raloxifene 60 mg daily and weekly placebo identical to alendronate for 12 months.
Main outcome measures. Evaluations included BMD of the lumbar spine and hip and markers of bone turnover at 6 and 12 months and adverse event reporting.
Results. Alendronate demonstrated substantially greater increases in BMD than raloxifene at both lumbar spine and hip sites at 12 months. Lumbar spine BMD increased 4.8% with alendronate vs. 2.2% with raloxifene (P < 0.001). The increase in total hip BMD was 2.3% with alendronate vs. 0.8% with raloxifene (P < 0.001). Reductions in bone turnover were significantly larger with alendronate than raloxifene. Overall tolerability was similar, however, the proportion of patients reporting vasomotor events was significantly higher with raloxifene (9.5%) than with alendronate (3.7%, P = 0.010). The proportion of patients reporting gastrointestinal events was similar between groups.
Conclusion. In postmenopausal women with low bone density, improvements in BMD and markers of bone turnover were substantially greater during treatment with alendronate compared to raloxifene.