A Randomized, Controlled Dose-Ranging Study of Risedronate in Children With Moderate and Severe Osteogenesis Imperfecta

Moderate to severe osteogenesis imperfecta is associated with multiple fractures in childhood. There are no published data regarding the effects of third-generation bisphosphonates in these children. This randomized study investigated which of three different doses of risedronate was most effective in reducing fracture incidence. We randomly assigned 53 children with moderate to severe osteogenesis imperfecta to receive 0.2, 1, or 2 mg/kg per week of risedronate. We assessed safety, fracture incidence, and bone measurement outcomes at 3, 6, 12, 18, and 24 months. At 24 months, 69% of children assigned 0.2 mg/kg per week had had new fractures compared with 44% receiving 1 mg/kg per week and 75% receiving 2 mg/kg per week. Poisson regression with age and prior fracture as covariates showed that there was no difference in incident nonvertebral fracture between groups. Fracture rate diminished in each group during the trial compared with previous the 2 years (p = .005). Lumbar spine bone mineral density increased significantly (p = .009) only in the 2 mg/kg per week group. Long bone bowing deformities reduced more in children receiving 1 or 2 mg/kg per week of risedronate [odds ratio (OR) 0.67, 95% confidence interval (CI) 0.48-0.93 per unit increase in risedronate dose, p = .015]. There were no serious adverse events. Bone mass increased and bowing deformities reduced with increasing risedronate dose. Children suffered fewer fractures irrespective of risedronate dose. The most appropriate dose of risedronate for children with moderate to severe osteogenesis imperfecta in this study was 2 mg/kg per week. (C) 2010 American Society for Bone and Mineral Research.