Efficacy and safety of monthly oral ibandronate in the prevention of postmenopausal bone loss

Introduction: Monthly oral ibandronate has been shown to increase bone mineral density (BMD) and reduce bone turnover in postmenopausal women with osteoporosis, but its efficacy has not been investigated in women with low bone mass. The objective of this study was to examine the efficacy and safety of monthly oral ibandronate (150 mg) treatment in postmenopausal women with low bone mass. Methods: This 1-year, double-blind, placebo-controlled, randomized study enrolled ambulatory postmenopausal women aged 45-60 years with baseline lumbar spine (LS) BMD T-score<-1.0 and >-2.5 and baseline T-score>-2.5 at the total hip, trochanter, and femoral neck (collectively defined as the proximal femur) and no prior vertebral or low-trauma osteoporotic fractures at baseline. Subjects received either 150 mg monthly oral ibandronate or placebo. All subjects received calcium and vitamin D supplements. The primary endpoint was the relative change from baseline (%) in mean LS BMD at 1 year (intent-to-treat population). Treatment groups were compared by means of a two-way ANOVA model which adjusted for independent factors including treatment group, baseline LS BMD T-score, and time since menopause. Responder analyses examined the of with changes from baseline in LS BMD and percentage participants proximal femur BMD >= 0%. Adverse events and safety laboratory parameters were monitored continuously. Results: A total of 77 women received monthly ibandronate and 83 women received placebo. Subjects treated with ibandronate achieved larger increases in LS BMD after 1 year compared with subjects receiving placebo (3.7% vs -0.4% [difference of 4.1 %, p<0.0001]). After 3 months, median serum C-terminal telopeptide of type 1 collagen levels were reduced by >55% in the ibandronate group compared with similar to 4% in the placebo group. At 1 year, 88.2% of the participants treated with ibandronate achieved increases in LS BMD >= 0% compared with 38.6% of subjects receiving placebo. Treatment regimens were well tolerated in both the ibandronate-treated and placebo groups. Conclusion: Monthly ibandronate therapy prevents bone loss in postmenopausal women with low bone mass. (C) 2008 Elsevier Inc. All rights reserved.