Abstract
Objectives: BONE (oral iBandronate Osteoporosis vertebral fracture trial in North America and Europe) determined whether less frequent dosing of ibandronate (dose-free interval > 2 months) provided similar antifracture efficacy to daily dosing. As osteoporosis medications must be effective across different populations, an additional objective of BONE was to investigate and report the effect of oral ibandronate in North American and European women, as described here. Patients and methods: BONE was a randomized, double-blind, placebo-controlled, fracture-prevention study in 2946 postmenopausal women (age 55 years-80 years; ≥ 5 years since menopause) with osteoporosis (low lumbar spine bone mineral density and one to four prevalent vertebral fractures [T4-L4]). Participants received daily calcium (500 mg) and vitamin D (400 IU) plus either placebo, oral daily ibandronate (2.5 mg) or oral intermittent ibandronate (20 mg every other day for 12 doses every 3 months). The efficacy and tolerability of ibandronate were assessed independently in both North American and European populations. Results: Consistent, significant efficacy was observed in the North American (new vertebral fracture risk reduction: 60% and 54% with daily and intermittent ibandronate, respectively) and European patient populations (50% and 48%, respectively). Both ibandronate regimens also significantly reduced the incidence of new, worsening, and acute clinical, vertebral fractures. Daily and intermittent ibandronate significantly increased bone density at the spine in both North American (5.4% and 4.4% vs. baseline with daily and intermittent ibandronate, respectively) and European (7.1% and 6.3% vs. baseline, respectively) populations. Significant increases were also observed for total hip bone density (2.6% and 3.7% vs. baseline for daily, and 2.5% and 3.1% for intermittent; North American and European populations, respectively). Comparable, significant decreases in biochemical markers of bone turnover (reductions in urinary excretion of C-telopeptide levels of 53.5% and 67.1% vs. baseline for daily, and 50.0% and 53.8% for intermittent; North American and European populations, respectively) were also observed in both populations (p <0.004 for all cited measurements in each ibandronate group vs. placebo). Oral ibandronate was well tolerated in both North American and European patients, with a safety profile similar to placebo. Conclusions: Oral ibandronate, administered daily or intermittently, effectively reduced vertebral fracture risk in North American and European women with postmenopausal osteoporosis. These results demonstrate the efficacy of ibandronate administered with extended dose-free intervals, regardless of patients' geographical origin. Research investigating other less frequent ibandronate regimens, such as once-monthly oral administration, is underway.