Influence on the bone mineral density and bone metabolism marker after the interruption and reinitiation of monthly minodronate therapy in postmenopausal women with osteoporosis.

Objectives: The purpose of this study was to investigate the influences of interruption and reinitiation of monthly minodronate therapy on the bone mineral density (BMD) and bone metabolism markers in postmenopausal women with osteoporosis.

Methods: Study patients were included if they had been administered monthly minodronate therapy for ≥6 months, interrupted the therapy, and reinitiated the therapy for ≥12 months. The BMD and bone metabolism markers were assessed at 4 time points: initiation, interruption, reinitiation and 1 year after reinitiation of therapy.

Results: A total of 23 patients were enrolled. The mean monthly minodronate treatment period was 23.8 ± 12.9 months following a mean interruption period of 11.9 ± 5.4 months. Once increased by monthly minodronate treatment for 2 years on average, the BMD of lumbar spine and radius did not significantly decrease even after an interruption for 1 year on average. However, the BMD of the femoral neck did decrease after interruption. The BMD of the lumbar spine and radius increased further after 1 year of monthly minodronate retreatment. The BMD of the femoral neck did not change. Once decreased after the treatment for an average of 2 years followed by an interruption for 1 year, bone metabolism markers increased gradually but did not recover to baseline levels. A potent suppressive effect on bone resorption was noted. The change rate was greater for the bone formation marker procollagen 1 N-terminal propeptide.

Conclusions: Monthly minodronate treatment increases BMD and reduces bone metabolism markers. The effect lessens after treatment interruptions, and can be restored by retreatment.