Burosumab for tumour-induced osteomalacia

Burosumab is in clinical development for the treatment of adults with tumour-induced osteomalacia (TIO). TIO is a rare disease where an overproduction of FGF23 leads to renal phosphate wasting and low levels of phosphate and vitamin D in the body. This causes weakening (or softening) of bones. Main symptoms include bone pain, muscle weakness/fatigue and fractures and without a timely diagnosis, TIO can lead to a significant decrease in quality of life, severe functional impairment and even prostration.
Burosumab is administered by subcutaneous injection. Burosumab is designed to recognise and attach to a protein called FGF23. By attaching to the FGF23 protein, burosumab blocks its activity, thus restoring phosphate and vitamin D levels by achieving phosphate homeostasis. If licensed, burosumab will provide a treatment option for TIO.