What conditions is Crysvita (burosumab-twza) used to treat?
Medically reviewed by Drugs.com. Last updated on June 11, 2025.
Crysvita (burosumab-twza) is used to X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO).
Crysvita (burosumab-twza) is classified as a fibroblast growth factor 23 (FGF23) blocking antibody. It is a recombinant fully human monoclonal IgG1 antibody directed against human fibroblast growth factor 23 (FGF23). FGF23 is a hormone that reduces serum levels of phosphorus and active vitamin D by regulating phosphate excretion and active vitamin D production by the kidney.
Crysvita is used for the treatment of:
- X-linked hypophosphatemia in adult and pediatric patients 6 months of age and older.
- FGF23-related hypophosphatemia in tumor-induced osteomalacia (TIO) associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized in adult and pediatric patients 2 years of age and older.
X-linked hypophosphatemia (XLH) leads to low phosphorus levels in the body and treatment with vitamin D is not effective for this type of rickets. Impaired bone growth in childhood and problems with bone mineralization can occur.
Tumor-Induced Osteomalacia (TIO) is a rare disease caused by typically benign, slow-growing tumors that produce excess levels of FGF23, which is involved in phosphate reabsorption. Patients with TIO can experience symptoms including severe hypophosphatemia (low levels of phosphate in the blood), osteomalacia (softening of the bones), muscle weakness, fatigue, bone pain and fractures.