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Burosumab (Crysvita)

Section: Injections
Effective Date: February 01, 2019
Revised Date: January 27, 2020


Burosumab-twza (Crysvita) is a human immunoglobulin G subclass 1 (IgG1), fibroblast growth factor 23 (FGF23) blocking antibody indicated for the treatment of X-linked hypophosphatemia (XLH) in adult and pediatric individuals one (1) year of age and older.

XLH is caused by excess FGF23 which suppresses renal tubular phosphate reabsorption and the renal production of 1,25 dihydroxy vitamin D.

X-linked hypophosphatemia has also been referred to as X-linked hypophosphatemic rickets, Hypoposphatemic rickets, X-linked dominant hypophosphatemic rickets (XLHR), X-linked rickets (XLR), Vitamin D-resistant rickets, X-linked Vitamin D-resistant rickets (VDRR), Hypophosphatemic vitamin D-resistant rickets (HPDR), Phosphate diabetes, and Familial hypophosphatemic rickets.


Coverage is subject to the specific terms of the member's benefit plan.

Federal Employee Program members (FEP) should check with their Retail Pharmacy Program to determine if prior approval is required by calling the Retail Pharmacy Program at 1-800-624-5060 (TTY: 1-800-624-5077). FEP members can also obtain the list through the website.

Burosumab (Crysvita) is considered medically necessary in adult and pediatric individuals one (1) year of age or older who meet ALL of the following:

  • Diagnosis of XLH, verified by pathogenic mutation in PHEX; and
  • Oral phosphate and active vitamin D analogs have been discontinued and will remain discontinued at least 7 days before and during ongoing treatment with burosumab (Crysvita); and
  • Documentation of fasting serum phosphorus concentration below the reference range for age; and
  • At least ONE of the following:
    • Documentation of low tubular resorption of phosphate corrected for glomerular filtration rate (TmP/GFR) based on age; or
    • Documentation of any of the following signs and symptoms of XLH including but not limited to growth retardation, bone fractures, musculoskeletal pain, dental abscesses, x-ray imaging showing deformities, or Thacher Rickets Severity Score (RSS),

Continuation of therapy with burosumab (Crysvita) after twelve (12) months may be considered medically necessary for the treatment of an individual with documented diagnosis of XLH when the following criteria are met:

  • Diagnosis of XLH; and
  • Documentation of improved fasting serum phosphorus concentration in relation to age (doses should be held if serum phosphorus is above 5 mg/dL); and
  • Documentation of improved TmP/GFR level if previously reported; and
  • Documentation of improved signs and symptoms of XLH such as a lower score on the Thacher Rickets Severity Score (RSS).

The use of burosumab (Crysvita) is considered experimental/investigational and, therefore, non-covered for all other indications. Scientific literature does not support its use for other indications.

Procedure Codes


NOTE: In addition to the above criteria, product specific dosage and/or frequency limits may apply in accordance with the U.S. Food and Drug Administration (FDA)-approved product prescribing information, national compendia, Centers for Medicare and Medicaid Services (CMS) and other peer reviewed resources or evidence-based guidelines. Blue Cross Blue Shield of North Dakota may deny, in full or in part, reimbursement for utilization that does not fall within the applicable dosage and/or frequency limits.

Diagnosis Codes

E83.31 E83.39

Professional Statements and Societal Positions Guidelines