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 inci dence in osteogenesis imperfecta (OI). Intravenous pamidronate was administ ered at 1.5 mg/kg bi-monthly to six children with OI, over 12-23 months. Th e number of fractures decreased from median of 3 (range 1-12) to 0 fracture s/year (range 0-4) (P < 0,05). After 12 months of treatment. there was sign ificant improvement in areal bone mineral density (BMD) z-scores of the lum bar 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 res orption marker) decreased from a median of 461.5 bone collagen equivalent/c reatinine (BCE/Cr) (range 129-721 BCE/Cr) to 223.5 BCE/Cr (range 107-312 BC E/Cr) (P < 0.05) and serum alkaline phosphatase (ALP) (bone formation marke r) from a median of 230.0 U/1 (range 148-305 U/1) to 133.5 U/1 (range 79-23 3 U/1) (P < 0.05), reflecting reduced bone turnover. This may represent a n et 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 y ear cyclical pamidronate is effective and safe in improving bone mineralisa tion and reducing fracture incidence in osteogenesis imperfecta.