Clinical characteristics and outcomes of paediatric CNO: a retrospective cohort study with focus on zoledronic acid
Yehonatan Herman, Jonathan D Akikusa, Julie Jones, Georgina M Tiller, Jane E Munro, Peter Simm, Margaret Zacharin, Neelika Liyanage, Nisha Varma, William D RentonAbstract
Objectives
Chronic non-bacterial osteomyelitis is a rare autoinflammatory bone disease of childhood. Non-steroidal anti-inflammatory drugs are often used first-line, while conventional and biologic disease-modifying antirheumatic drugs and bisphosphonates are reserved for severe or refractory disease. Zoledronic acid is used off-label, but robust data on its role remain limited. This study aimed to describe the clinical characteristics, management, and outcomes of children with Chronic non-bacterial osteomyelitis, with primary focus on the effectiveness and tolerability of Zoledronic acid.
Method
A retrospective review was conducted of children diagnosed with chronic non-bacterial osteomyelitis between 2014 and 2024 at the Royal Children’s Hospital, Melbourne. Clinical and magnetic resonance imaging responses to ZA, as well as adverse effects, were evaluated.
Results
Fifty-seven patients were included (mean age 10.3 years; 70% female; median follow-up 3.7 years [range 1.4–8.9]). Multifocal disease was present in 86%, and 63% underwent biopsy. All received non-steroidal anti-inflammatory drugs initially. Twenty-two patients (37%) received zoledronic acid (mean 2.6 doses); 77% showed significant clinical improvement. Three later required tumour necrosis factor inhibitors, and two received tumour necrosis factor inhibitors without prior zoledronic acid. Among 10 patients with pre- and post-zoledronic acid whole body magnetic resonance imaging, 80% demonstrated significant radiological improvement. Mild, transient flu-like symptoms were reported in 54% of patients treated with zoledronic acid; no serious adverse events occurred.
Conclusion
Zoledronic acid was associated with high clinical and radiological response rates and was well tolerated. Its infrequent dosing schedule, typically one infusion every six months, offers a practical alternative to other bisphosphonates.