Intermittent intravenous ibandronate injections reduce vertebral fracture risk in corticosteroid-induced osteoporosis: results from a long-term comparative study

Despite its well-known benefits, chronic corticosteroid therapy causes osteoporotic fractures in approximately 30−50% of patients treated. To prevent the occurrence of these fractures, treatment with oral bisphosphonates is recommended. However, current oral bisphosphonates, which are given either daily or weekly, are associated with stringent, inconvenient dosing guidelines. Less frequent dosing may provide greater acceptability. The objective of this study was to investigate the efficacy and safety of ibandronate, a highly potent nitrogen-containing bisphosphonate, when given by intravenous (i.v.) injection every 3 months in men and women with established corticosteroid-induced osteoporosis (CIO; lumbar spine [L2-L4] bone mineral density [BMD] T-score ≤−2.5). A total of 115 participants were assigned to receive daily calcium supplements (500 mg) plus either ibandronate (2 mg) injections every 3 months or daily oral alfacalcidol (1 μg), for 3 years. Intermittent i.v. ibandronate injections produced significantly greater increases in mean BMD at the lumbar spine (13.3% versus 2.6%, respectively; p<0.001), and femoral neck (5.2% versus 1.9%, respectively; p<0.001) versus daily oral alfacalcidol, after 3 years, relative to baseline. This study was not statistically powered to show a difference between the groups with respect to fracture incidence. Nevertheless, after 36 months, the frequency of patients with new vertebral fractures was significantly lower in the patients receiving ibandronate relative to those taking alfacalcidol (8.6% versus 22.8%, respectively; p=0.043). This is the first time that significant vertebral fracture reduction has been demonstrated with an i.v. bisphosphonate in CIO. Patients treated with i.v. ibandronate injections also experienced less back pain (p<0.001) and less height loss (p=0.001) than those receiving oral alfacalcidol. Both regimens were well tolerated. In conclusion, intermittent i.v. ibandronate injections are efficacious, well-tolerated, and convenient, and promise to offer physicians an important therapeutic advance in the management of osteoporosis.