Three years of treatment with minodronate in patients with postmenopausal osteoporosis.

The objective of this study was to determine the safety and efficacy of long-term minodronate treatment in women with postmenopausal osteoporosis based on re-analysis of a phase III 2-year clinical trial with a 1-year extension. Women aged 55-80 years old with fragility fractures were enrolled and randomized to take 1 mg minodronate or placebo once a day in the original 2-year study. The subjects who completed the 2-year study were invited to participate in an additional 1-year extension in which all subjects were to receive minodronate. Finally, a total 380 subjects completed the extension study (186 from the placebo group and 194 from the minodronate group). Fracture results observed in the extension study were consistent with those observed in the first 2 years in minodronate group. In contrast, the placebo/minodronate group showed a decreased incidence of new vertebral fractures during year 3 compared to that in year 2. In the patients who received minodronate in the original 2-year study, lumbar bone mineral density (BMD) increased consistently during year 3 and bone turnover markers decreased within the first 6 months and remained constant thereafter over 3 years. Similar positive effects of minodronate on BMD and bone turnover markers occurred when therapy was initiated in the placebo/minodronate group. No new safety concerns observed during the extension period compared to the safety observations made during the 2-year study. It was concluded that daily administration of 1 mg oral minodronate is safe and well tolerated, and that the efficacy of this dose in reducing vertebral fracture risk in postmenopausal women over 2 years is sustained with continuing treatment.