Burosumab-twza (Crysvita® ) Notification

• Burosumab-twza (Crysvita® ) subcutaneous injection for administration by a healthcare professional 

• For adult and pediatric patients 6 months of age and older with X-linked hypophosphatemia 
• For adult and pediatric patients 2 years of age and older with fibroblast growth factor 23 (FGF23)-related hypophosphatemia in tumorinduced osteomalacia associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized 

The restricted product(s) may be considered medically necessary when the following criteria are met:

Initial Criteria for Approval:

1. The patient has a diagnosis of X-linked hypophosphatemia (XLH) [medical record documentation required]; AND 
   1. The patient is 6 months of age or older; AND
   2. The diagnosis has been confirmed by at least ONE of the following:
      1. Genetic testing demonstrating PHEX genetic mutation [medical record documentation required]; OR
      2. Elevated levels of serum fibroblast growth factor 23 (FGF23) that support the diagnosis [medical record documentation required]; OR
      3. BOTH of the following: 
         1. The prescriber has provided documentation indicating the patient has a directly related family member with known PHEX genetic mutation [medical record documentation required]; AND 
         2. The patient has evidence of radiographic and/or biochemical abnormalities consistent with a diagnosis of XLH [medical record documentation required]; AND
   3. The patient has documented laboratory testing to support the diagnosis, including serum phosphorus level below the age-related reference range and reduced renal tubular resorption of phosphate corrected for glomerular filtration rate [medical record documentation required]; AND 
   4. For adults, the patient has clinical symptoms of XLH (e.g., skeletal pain, bone fractures) [medical record documentation required]; OR
2. The patient has a diagnosis of tumor-induced osteomalacia (TIO) associated with phosphaturic mesenchymal tumors [medical record documentation required]; AND 
   1. The patient is 2 years of age or older; AND
   2. The requested agent is being used to treat FGF23-related hypophosphatemia, as confirmed by BOTH of the following [medical record documentation required]:
      1. Elevated levels of intact FGF23 [medical record documentation required]; AND 
      2. Serum phosphorus level below the age-related reference range [medical record documentation required]; AND 
   3. The tumor cannot be surgically resected or localized [medical record documentation required]; AND
3. The patient will NOT be taking the requested agent in combination with an oral phosphate or active vitamin D analog [medical record documentation required]; AND
4. The patient does NOT have severe renal impairment or end stage renal disease [medical record documentation required]; AND 
5. The prescriber is a specialist in the area of the patient’s diagnosis (e.g., endocrinologist, nephrologist) or has consulted with a specialist in the area of the patient’s diagnosis [medical record documentation required]; AND 
6. The requested quantity does NOT exceed the maximum units allowed for the duration of approval (see table below); AND 
7. For requests for injection or infusion administration of the requested medication in an inpatient or outpatient hospital setting, Site of Care Criteria applies.

Duration of Approval: 365 days (1 year) 

Continuation Criteria for Approval:

1. .The patient was approved through Blue Cross NC initial criteria for approval; OR 
2. The patient would have met initial criteria for approval at the time they started therapy; AND
3. The patient has demonstrated positive clinical response with one or more of the following while using the medication [medical record documentation required]:
   1. Improvement in severity of rickets/osteomalacia; OR
   2. Increase in serum phosphorus level; OR 
   3. Reduction of fractures and bone pain; AND
4. The patient will NOT be taking the requested agent in combination with an oral phosphate or active vitamin D analog [medical record documentation required]; AND
5. The patient does NOT have severe renal impairment or end stage renal disease [medical record documentation required]; AND
6. The prescriber is a specialist in the area of the patient’s diagnosis (e.g., endocrinologist, nephrologist) or has consulted with a specialist in the area of the patient’s diagnosis [medical record documentation required]; AND 
7. The requested quantity does NOT exceed the maximum units allowed for the duration of approval (see table below); AND
8. For requests for injection or infusion administration of the requested medication in an inpatient or outpatient hospital setting, Site of Care Criteria applies. 

Duration of Approval: 365 days (1 year)

1. For requests for injection or infusion administration in an inpatient setting, the injection or infusion may be given if the above medical necessity criteria are met AND the inpatient admission is NOT for the sole purpose of administering the injection or infusion; OR 
2. For requests for injection or infusion administration in an outpatient hospital setting, the injection or infusion may be given if the above medical necessity criteria are met AND ONE of the following must be met: 
   1. History of mild adverse events that have not been successfully managed through mild pre-medication (e.g., diphenhydramine, acetaminophen, steroids, fluids, etc.); OR
   2. Inability to physically and cognitively adhere to the treatment schedule and regimen complexity; OR
   3. New to therapy, defined as initial injection or infusion OR less than 3 months since initial injection or infusion; OR
   4. Re-initiation of therapy, defined as ONE of the following: 
      1. First injection or infusion after 6 months of no injections or infusions for drugs with an approved dosing interval less than 6 months duration; OR 
      2. First injection or infusion after at least a 1-month gap in therapy outside of the approved dosing interval for drugs requiring every 6 months dosing duration; OR 
   5. Requirement of a change in the requested restricted product formulation; AND
3. If the Site of Care Medical Necessity Criteria in #1 or #2 above are not met, the injection or infusion will be administered in a home-based infusion or physician office setting with or without supervision by a certified healthcare professional.

All information referenced is from FDA package insert unless otherwise noted below.

1. Carpenter TO, Imel EA, Holm, IA, et al. A clinician’s guide to X-linked hypophosphatemia. J Bone Miner Res. 2011;26(7):1381-1388.
2. Carpenter TO, Whyte MP, Imel EA, et al. Burosumab therapy in children with X-linked hypophosphatemia. N Engl J Med. 2018;378(21):1987-1998. 

October 2021: Criteria change: Added Site of Care medical necessity criteria. Policy notification given 8/2/2021 for effective date 10/1/2021.

June 2021: Criteria change: Added new indication for fibroblast growth factor 23 (FGF23)-related hypophosphatemia in tumor-induced osteomalacia (TIO) associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized; added maximum units; medical policy formatting change. Policy notification given 4/16/2021 for effective date 6/16/2021.

Further historical criteria changes and updates available upon request from Medical Policy and/or Corporate Pharmacy.