Cyclic pamidronate infusion improves bone mineralisation and reduces fracture incidence in osteogenesis imperfecta

A prospective open study was performed to determine the efficacy and safety of pamidronate in improving bone mineralisation and reducing fracture incidence in osteogenesis imperfecta (OI). Intravenous pamidronate was administered at 1.5 mg/kg bi-monthly to six children with OI, over 12-23 months. The number of fractures decreased from median of 3 (range 1-12) to 0 fractures/year (range 0-4) (P < 0,05). After 12 months of treatment. there was significant improvement in areal bone mineral density (BMD) z-scores of the lumbar spine from median of -2.40 (range -3.20 to -1.67) to -1.90 (range -2.38 to -0.91) (P < 0.05) and in the volumetric BMD which increased from median of 0.095 to 0.146 g/cm(3) (P < 0.05). Urine N-telopeptide levels (bone resorption marker) decreased from a median of 461.5 bone collagen equivalent/creatinine (BCE/Cr) (range 129-721 BCE/Cr) to 223.5 BCE/Cr (range 107-312 BCE/Cr) (P < 0.05) and serum alkaline phosphatase (ALP) (bone formation marker) from a median of 230.0 U/1 (range 148-305 U/1) to 133.5 U/1 (range 79-233 U/1) (P < 0.05), reflecting reduced bone turnover. This may represent a net reduction in bone resorption and provides a biochemical explanation for the increase in bone mineralisation. Height standard deviation scores were not affected and there were no significant adverse effects. Conclusion: 1 year cyclical pamidronate is effective and safe in improving bone mineralisation and reducing fracture incidence in osteogenesis imperfecta.