Burosumab-twza (Crysvita®)


Indications for Prior Authorization:

  • Treatment of X-linked hypophosphatemia (XLH) in adult and pediatric patients 1 year of age and older

Patients must meet the following criteria for the indication(s) above:

  • Patient is 1 year of age or older, AND
  • Diagnosis of X-linked hypophosphatemia (XLH), AND
  • Prescribed by or in consultation with an endocrinologist or nephrologist, AND
  • Patient has a baseline serum phosphorus level below normal range for age, AND
  • Patient has a baseline tubular reabsorption of phosphate corrected for glomerular filtration rate that was below the normal range for age and gender, AND
  • Patient will not use oral phosphate and active Vitamin D analogs, AND
  • Patient does not have severe renal impairment or end stage renal disease


  • Pediatric XLH:
    • Starting dose: 0.8 mg/kg of body weight rounded to the nearest 10 mg, administered every 2 weeks. Minimum dose 10 mg up to a maximum dose of 90 mg.
    • Do not adjust Crysvita more frequently than every 4 weeks.
    • Dose may be increased up to approximately 2 mg/kg (maximum 90 mg), administered every 2 weeks to achieve normal serum phosphorus
  • Adult XLH:
    • Dose regimen: 1 mg/kg body weight rounded to the nearest 10 mg up to a maximum dose of 90 mg administered every 4 weeks


  • 1 year

Last review date: April 30, 2019

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