Cyclic Pamidronate Therapy in Children with Osteogenesis Imperfecta

he main objective of this study was to determine the efficacy and safety of pamidronate in improving bone mineralization and reducing fracture incidence in osteogenesis imperfecta (OI). Materials and Methods: Intravenous pamidro-nate was administered to 64 children, aged 18 months to 10 years old, with severe OI, in a 1 mg/kg single daily dose for 3 sequentional days at 4 month intervals, for over a period of 24-48 months. Clinical status, biochemical characteris-tics including bone turnover markers, the bone mineral density of the lumbar spine and femoral neck, and radiologic changes were assessed regularly during treatment. Results: The number of fractures decreased from median of 8 (range 4-11) to 0 fractures/year (range 0-4) (P<0.05). After 16 months of treat-ment, there was significant improvement in bone mineral density (BMD-DEXA) z-scores of the lumbar spine from median of -5.90 (range -7.01 to -4.76) to -2.70 (range -4.46 to -1.98) (P<0.001). Serum alkaline phosphatase (ALP) (bone formation marker) decreased from a me-dian of 731.0 U/L (range 438-998 U/L) to 183 U/L (range 95-286 U/L) (P<0.001), implying a signifi-cant reduction in bone turnover and its resorp-tion and increase in bone mineralization. There was no improvement either in their height growth velocities or in their standard deviation scores. Mobility and ambulation improved in all but 5 children, (all five took the drug for less than 2.5 years).There was a significant relief in chronic pain and fatigue but no adverse effects in any of the children using the drug. Conclusion: Cyclic pamidronate administration is effective in improving bone mineralization and reducing fracture incidence in childhood os-teogenesis imperfecta.