Effect of cyclical intravenous pamidronate therapy in children with osteogenesis imperfecta. Open-label study in seven patients

OBJECTIVES: To evaluate the efficacy of pamidronate in protecting against fractures, increasing bone mineral density (BMD), and decreasing bone remodeling marker levels in children with osteogenesis imperFecta. PATIENTS AND METHODS: Seven children (two girls and five boys; mean age, 8.5 years) were given cyclical intravenous pamidronate (Aredia) for 1 to 7 years, with a mean cycle duration of 6 months and a mean dose of 1.86 mg/kg/cycle. Four patients had type III and three type IV disease according to the Sillence classification scheme. RESULTS: A trend toward a decrease in the fracture rate as compared to the pretreatment period was found, but the difference was not significant in this small sample (P = 0.09). Lumbar spine BMD showed a significant annual increase (+26.7%, P = 0.03) far greater than the expected mean annual increase related to growth. No significant decreases in bone remodeling markers were noted. CONCLUSION: Pamidronate seems useful in the treatment of osteogenesis imperfecta in children, since it increases BMD and reduces the fracture rate, in keeping with the findings from the larger series studied by Glorieux. Pamidronate is a symptomatic, noncurative treatment that does not correct the genetic abnormalities responsible for the histological bone alterations.