Benefits of pamidronate in children with osteogenesis imperfecta: an open prospective study.

OBJECTIVES

To study the efficacy of pamidronate in children with osteogenesis imperfecta (OI).

PATIENTS AND

METHODS

Twenty-nine patients (median age 8.7 years), were given pamidronate in cyclic infusions of 3 days. Patients received 3-13 cycles (median 6), at a dose of 0.5 mg/kg/day in infants (below 2 years of age) and 1 mg/kg/day in children (2 years and older). The interval time between cycles was 2 months in infants and 4 months in children. The median follow-up was 16 months. All patients received daily supplementation of calcium, vitamin D and physical rehabilitation. Assessments were performed at baseline and before each cycle. Fracture rate under treatment was compared to the one in the pre-treatment period.

RESULTS

Pain decreased after the first infusion cycle (P < 0.0001). The median of fracture incidence decreased from 15 to 0.5 per year in infants and from 2.0 to 1 per year in children (P = 0.04). Alkaline phosphatase decreased by 31.2% and N-telopeptide collagen cross-links decreased by 61.8% (P < 0.001). Bone mineral density (BMD) of the spine increased by a median of 55.4% (P < 0.001). Z-scores increased from a median of -4.7 to -2.6 (P < 0.001). The femoral neck, BMD increased by a median of 16%. The area of the first four lumbar vertebrae increased by a median of 21.5% (P < 0.001). No adverse effect on growth or on fracture healing was observed. Side effects were symptomatic hypocalcemia in one infant, and the transient acute phase reaction.

CONCLUSION

Pamidronate increases BMD, decreases bone remodeling markers, pain and fracture rate in infants and children with OI.