Efficacy and safety of oral weekly ibandronate in the treatment of postmenopausal osteoporosis

Adherence to oral daily bisphosphonate regimens in postmenopausal osteoporosis is currently suboptimal. Less frequent dosing regimens are likely to improve patient adherence and thus, potentially, patient outcomes. A multicenter, randomized, double-blind, noninferiority study was conducted in 235 women (53-80 yr old; time since menopause greater than or equal to 3 yr) with postmenopausal osteoporosis [lumbar spine (L1-L4) bone mineral density (BMD) T-score less than or equal to -2] to demonstrate the noninferiority of an oral weekly (20 mg) ibandronate regimen compared with an oral daily (2.5 mg) ibandronate regimen. All patients received daily calcium (500 mg) and vitamin D (400 IU). The primary analysis was the relative change in lumbar spine (L1-L4) BMD from baseline after 48 wk in the perprotocol population. Daily and weekly ibandronate significantly increased spinal BMD by 3.47 and 3.53%, respectively, and provided substantial and similar decreases in biochemical markers of bone turnover. In the primary analysis, noninferiority of the weekly regimen to the daily regimen was demonstrated, with the boundary of the one-sided confidence interval, -0.96%, within both the -1.65% prespecified margin and a more stringent margin of -1.10%. These results demonstrate that oral weekly ibandronate provides the same efficacy and safety as oral daily ibandronate in women with postmenopausal osteoporosis.