Crysvita®

Drug - Crysvita® (burosumab-twza) [Ultragenix Pharmaceutical Inc.]

December 2018

Therapeutic area - Fibroblast Growth Factor 23 (FGF23) Inhibitors, mab (C7J)

Initial approval criteria

Patient is at least 1 year of age AND
Patient has not received oral phosphate and/or active vitamin D analogs within 1 week prior to the start of therapy AND
Must be prescribed by, or in consultation with, a nephrologist or endocrinologist AND
Patient must have a diagnosis of X-linked Hypophosphatemia (XLH) confirmed by at least one of the following:
- Serum fibroblast growth factor-23 (FGF23) level > 30 pg/mL OR
- Phosphate regulating gene with homology to endopeptidases located on the X chromosome (PHEX-gene) mutations in the patient AND
Patient has a reduced tubular resorption of phosphate corrected for glomerular filtration rate (TmP/GFR) AND
Baseline fasting serum phosphorus level with current hypophosphatemia, defined as a phosphate level below the lower limit of the laboratory normal reference range AND
Patient does not have severe renal impairment, defined as a glomerular filtration rate (GFR) of < 30 mL/min
Initial approval is for 6 months

Patient continues to meet the criteria identified in section the initial approval section AND
Absence of unacceptable toxicity from the drug AND
Current serum phosphorus level is not above the upper limit of the laboratory normal reference range AND
Disease response as indicated by increased serum phosphorus levels, a reduction in serum total alkaline phosphatase activity, improvement in symptoms (e.g., skeletal pain, linear growth), and/or improvement in radiographic imaging of rickets/osteomalacia
Renewal approval is for 12 months

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