Burosumab: First Global Approval.
Burosumab (Crysvita®; Kyowa Hakko Kirin Co., Ltd. and Ultragenyx Pharmaceutical Inc.) is a fully human monoclonal antibody directed at fibroblast growth factor 23 (FGF23). Excessive FGF23 production has been implicated in various hypophosphataemic diseases. Inhibition of FGF23 by burosumab results in increased renal phosphate reabsorption and increased serum levels of phosphorus and active vitamin D. In February 2018, the EMA granted subcutaneous burosumab conditional marketing authorization for the treatment of X-linked hypophosphataemia (XLH) with radiographic evidence of bone disease in children one year of age and older and adolescents with growing skeletons. In April 2018, the US FDA approved burosumab for the treatment of XLH in adults and children one year of age and older. Multinational phase III trials of burosumab are currently underway in adult and paediatric patients with XLH. Burosumab is also being evaluated in the phase II setting in adults with tumour-induced osteomalacia and epidermal nevus syndrome in the USA, as well as in Japan and Korea. This article summarizes the milestones in the development of burosumab leading to its first global approval in the EU for XLH in paediatric patients.