Zoledronic acid treatment in children with osteogenesis imperfecta.

BACKGROUND

Intravenous disodium pamidronate has become an established treatment in osteogenesis imperfecta (OI). Another bisphosphonate, zoledronic acid, has been indicated for the treatment of adult osteoporosis. We studied its efficacy and safety in children with mild OI.

METHODS

Patients were treated for 1.0-3.2 years with 0.05 mg/kg zoledronic acid intravenously every 6 months as part of their clinical care. They were carefully followed for clinical and biochemical parameters, side effects, bone mineral densities (BMD) and compression fractures.

RESULTS

The study included 17 patients (age 1.5-16.8 years) with type I OI. They had sustained altogether 73 fractures; 9 had compression fractures. During the treatment, 6 patients suffered in total 10 new long-bone fractures. The median lumbar spine areal BMD z-score increased from -2.0 to -0.7 during 2 years of treatment. The infusions were associated with a transient decrease in serum calcium and phosphate and a significant increase in serum PTH. Two patients developed symptomatic hypocalcemia. Bone turnover markers decreased during the treatment.

CONCLUSIONS

Intravenous zoledronic acid is an effective mode of treatment in children with OI. The treatment response is comparable to pamidronate but the infusion protocol is more convenient. Further studies are needed to establish optimal dosing and long-term safety.