Crysvita

Crysvita is a medicine used for the treatment of X-linked hypophosphataemia, a hereditary disorder characterised by low levels of phosphate in the blood (hypophosphataemia). Phosphate is essential to build bones and teeth and to maintain their strength, so patients may develop rickets and other bone deformities and growth problems. Crysvita can be used to treat children and adolescents between 1 and 17 years of age when signs of bone disease are seen on X-rays, and in adults. Crysvita is also used to treat osteomalacia (softening and weakening of the bones) caused by phosphaturic mesenchymal tumours. This type of tumour produces hormones, particularly a substance called fibroblast growth factor 23 (FGF23), which cause the body to lose phosphate. Crysvita is used in patients from 1 year of age, when the tumour cannot be located or removed by surgery. Crysvita contains the active substance burosumab. These diseases are rare, and Crysvita was designated an ‘orphan medicine’ (a medicine used in rare diseases). Further information on the orphan designations can be found on the European Medicines Agency’s website ( [X-linked hypophosphataemia](/en/medicines/human/orphan-designations/eu-3-14-1351): 15 October 2014; [phosphaturic mesenchymal tumour](/en/medicines/human/orphan-designations/eu-3-18-2011): 16 April 2018).