Efficacy and tolerability of alendronate once weekly in Asian postmenopausal osteoporotic women

BACKGROUND: Osteoporosis has become a major health problem worldwide, and the incidence is rising in Asian countries. The aminobisphosphonates are potent inhibitors of bone resorption and are currently the mainstay of treatment for postmenopausal osteoporosis. Dosing frequency will likely affect tolerability and adherence to treatment. OBJECTIVE: To assess the tolerability and efficacy of a once-weekly aminobisphosphonate preparation in improving bone mineral density (BMD) and bone turnover markers in osteoporotic Asian women. METHODS: Chinese postmenopausal women with osteoporosis were randomized to receive either alendronate 70 mg once weekly plus calcium carbonate 500 mg daily (n = 29) or calcium carbonate 500 mg daily (n = 29) for one year. BMD was measured by dual energy X-ray absorptiometry. Markers of bone formation and bone resorption included plasma total alkaline phosphatase and urine N-telopeptides. RESULTS: Treatment with alendronate 70 mg once weekly for one year resulted in significant BMD improvement of 6.1% at the spine, 5.6% at the femoral neck, and 3.5% at the total hip. There was no significant change in the BMD values in the calcium group (spine 1.4%, femoral neck -0.2%, total hip 0%). The BMD response in the alendronate group was significantly different from that in the calcium group at all time points, and the difference was detectable as early as after 3 months of treatment (ANOVA p < 0.001). The changes remained significant after adjusting for age, age at menarche, and years since menopause (p < 0.001). Similarly, the reductions in bone markers at 12 months were significantly different between the 2 treatment groups (plasma total alkaline phosphatase: alendronate 27.9%, calcium 5.4%; urine N-telopeptide: alendronate 55.6%, calcium 11.2%; both p < 0.001). The alendronate regimen was well tolerated, without significant adverse events. CONCLUSIONS: The results confirmed that once-weekly alendronate was efficacious in increasing BMD and reducing bone turnover and was well tolerated in Asian women.