Zoledronic acid treatment in infants and toddlers with osteogenesis imperfecta is safe and effective: A tertiary care centre experience

Abstract

Context: Osteogenesis imperfecta (OI) is a genetic disorder of the extracellular matrix of bone characterized by low bone mass manifesting as frequent fractures, delayed motor development, pain, and impaired quality of life. The intravenous bisphosphonate, pamidronate is an established treatment for OI. Recently, zoledronic acid (ZA) has been used for the management of OI. Aim: To assess the efficacy and safety of ZA in children below five years of age with OI. Settings and Design : A hospital-based prospective observational study. Methods and Material : Patients with OI aged less than five years attending our centre were treated with intravenous ZA at a dose of 0.05 mg/kg every six months. Subjects were closely monitored for clinical and biochemical variables, adverse events, and new-onset fractures. The response to therapy was assessed by monitoring clinical variables including the degree of bony pains, number of fractures, height/length standard deviation score (SDS), and motor developmental milestones. All patients were analysed at baseline and at the end of two years for biochemical parameters and clinical severity score (CSS) as proposed by Aglan et al. with modifications. Results : After two years of treatment, OI patients showed a significant decline in the rate of fractures (p < 0.001), improvement in ambulation (p = 0.005), alleviation of pain (p < 0.001), and improvement in height SDS (p < 0.05). There was a significant improvement in CSS after two years of therapy. Apart from mild flu-like symptoms and mild asymptomatic hypocalcaemia immediately post-infusion, no other adverse effect was noted. Conclusion : ZA therapy in infants and children below five years of age with OI was effective and safe and a more convenient alternative to pamidronate.

Keywords

• clinical severity score
• infants
• osteogenesis imperfecta
• zoledronic acid