Medical treatment of osteogenesis imperfecta

Abstract

Osteogenesis imperfecta (OI) comprises a group of disorders principally affecting type I collagen which result in increased bone fragility. Children with severe OI suffer recurrent fractures, resulting in severe deformity and growth stunting in many cases, with loss of independent ambulation by the teenage years in over 50% of cases. Recently, cyclical intravenous treatment with pamidronate has proven of benefit to children with severe forms of OI. Bone mineral density (BMD) and physical activity increased markedly in these patients and fracture rate decreased. In our experience with more than 160 children with OI treated with pamidronate, BMD increases dramatically and the incidence of radiologically confirmed fractures falls. The treatment does not alter fracture healing, growth rate, or growth plate appearances. Dependence on mobility aids is reduced and all subjects able to communicate reported substantial relief of chronic pain and fatigue. No adverse side effects were noted apart from the well-known acute phase reaction during the first infusion cycle. In our group of patients, pamidronate did not have a detrimental effect on growth. It is unclear at present how long pamidronate treatment should be continued, and which is the optimal treatment schedule and dosage. There were no significant side effects after 7 years of treatment, but longer surveillance is warranted. New bisphosphonates are under investigation to compare their effects to those of pamidronate. Although this form of therapy does not address the basic abnormalities that underlie the OI syndromes, it allows, for the first time, to significantly alter the natural course of the disease and improve patients' clinical status and quality of life. Drug Dev. Res. 49:141–145, 2000. © 2000 Wiley-Liss, Inc.