FDA Approves CRYSVITA for Tumor-Induced Osteomalacia

Ultragenyx Pharmaceutical’s therapy, CRYSVITA, has recently been approved by the FDA for the treatment of FGF23-related hypophosphatemia in tumor-induced osteomalacia (TIO) associated with phosphaturic mesenchymal tumors. This approval comes after CRYSVITA was evaluated in two Phase 2 trials.

About Tumor-Induced Osteomalacia (TIO)

TIO is a rare syndrome that is characterized by muscle weakness, bone pain, and fractures. It occurs when there are high levels of fibroblast growth factor 23 (FGF23), which is secreted by small endocrine tumors. These tumors are typically benign. This condition was only recently discovered, which has made it difficult to obtain a diagnosis and receive proper treatment. Medical professionals are striving to learn more about TIO in order to understand it more and provide better outcomes for patients.


The approval of this treatment is very important, as it addresses an unmet need within the rare disease community. CRYSVITA is the first and only approved treatment for hypophosphatemia associated with TIO. It is currently approved for those who are two years of age and older.

This therapy is an antibody that blocks FGF23. As an accumulation of this growth factor causes the characteristic symptoms of TIO, blocking it stops the symptoms.

Ultragenyx notes that there is important safety information that should be known before taking CRYSVITA. Those who experience severe renal impairment, have normal or heightened levels of serum phosphorus, or take oral phosphate and active vitamin D analogs. Patients should also stop treatment and contact their doctors if they experience adverse events, hypersensitivity, or injection site reactions. There is a lack of data on CRYSVITA being used during pregnancy, so ensure that you talk to your doctor if you are or may become pregnant.

The approval of this treatment is very exciting and important for those with tumor-induced osteomalacia.

Learn more about this story here.

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