Outcomes of Zoledronic Acid Use in Paediatric Conditions

<b><i>Introduction:</i></b> Limited evidence is available concerning experience with use of zoledronic acid (ZA) and treatment for conditions other than primary bone fragility. <b><i>Materials and Methods:</i></b> A retrospective review of all Royal Children Hospital patients who had been administered at least 1 dose of intravenous ZA from 2002 to 2015 was undertaken. <b><i>Results:</i></b> The audit included 309 children with 228 being treated for bone fragility conditions. Of the 228, 68 had height-adjusted lumbar spine bone mineral density Z-scores available over up to a 5-year period, and median increases were +2.0 SD (median absolute deviation = 0.9) (<i>N</i> = 36, <i>p</i> value for median increase of at least 0.5 in Z-score <0.001), for patients with osteogenesis imperfecta or other primary bone fragility disorders, +1.0 SD (0.9) (<i>N</i> = 14, <i>p</i> = 0.029), for immobility conditions, +0.5 SD (0.7) (<i>N</i> = 10, <i>p</i> = 0.399), and for glucocorticoid-induced secondary osteoporosis, +0.7 SD (0.6) (<i>N</i> = 8, <i>p</i> = 0.015). 81/309 children were treated for bone abnormality indications (e.g., avascular necrosis [AVN], fibrous dysplasia, and bone cysts). Of 39 with AVN, outcome data were available for 33, with joint integrity maintained for 24/33 from 6 to 24 months after last ZA, subjective reports (22/28) of reduced pain. Reduction in bone lesion size was seen in 2/4 patients with bone cysts within 12 months of ZA commencement. <b><i>Discussion/Conclusion:</i></b> This is the largest cohort of reported outcomes of ZA use in a paediatric population. Results demonstrate a good efficacy profile and associated improved bone density for osteoporotic conditions and stabilization of non-traumatic AVN with a low rate of joint collapse.