[Therapeutic agents for disorders of bone and calcium metabolism: Ibandronate]

Ibandronate is a potent nitrogen-containing bisphosphonate that can be administered by short (15 - 30 second) intravenous (i.v.) injection in regimens with extended dosing intervals; unlike in Caucasian women, the efficacy and safety of this formulation is yet to be fully explored in Japanese with osteoporosis. A 6-month, multicenter, randomized, double-blind, placebo-controlled study, involving 228 Japanese women with osteoporosis, was conducted to compare the efficacy and safety of the i.v. injection regimens. At 6 months, substantial increases in bone mineral density (BMD) were observed at the lumbar spine and proximal femur in the active treatment arms. For biochemical markers of bone turnover (urinary type I collagen cross linked C-terminal telopeptide [uCTX] and bone alkaline phosphatase [BAP]), the 1 mg monthly and 2 mg bi-monthly regimens were nominally more effective than the 0.5 mg monthly regimen; all ibandronate regimens were superior to placebo. The i.v. ibandronate injections were generally well tolerated, with a similar overall adverse event profile to placebo. No serious drug-related adverse events were reported. Monthly and bi-monthly i.v. ibandronate injections effectively reduce bone turnover and increase BMD in Japanese women with osteoporosis. Ibandronate injections provide a new option for the treatment of osteoporosis.