CurrentUnitedHealthcarePolicy 2025D0071N

Crysvita (burosumab-twza) for X-linked hypophosphatemia and FGF23-related hypophosphatemia in tumor-induced osteomalacia

UnitedHealthcare medical benefit drug policy describing medical necessity criteria, applicable procedure and diagnosis codes, dosing/authorization duration, prescriber requirements, and CMS considerations for burosumab (Crysvita) for XLH and for FGF23-related hypophosphatemia in TIO.

Policy Summary

PayerUnitedHealthcare

PolicyCrysvita (burosumab-twza) for X-linked hypophosphatemia and FGF23-related hypophosphatemia in tumor-induced osteomalacia

Policy CodePolicy 2025D0071N

Change TypeTemplate Update (07/01/2025)

Effective DateMay 1, 2025

Next Review Date

Key ActionSubmit documentation confirming diagnosis (genetic testing or FGF23 > 30 pg/mL or specified biochemical panel), patient age criteria, prescriber specialty or consultation, prior failure/intolerance to vitamin D analog + oral phosphate when required (TIO), baseline labs (serum phosphate, SCr, 25(OH)D), and planned dosing per FDA labeling; initial authorization limited to up to 12 months.

POLICY UPDATE CHANGES

07/01/2025 Template Update - Updated Benefit Considerations.

2Covered indications (XLH, TIO)

12 moMax authorization (initial/reauth)

J0584Primary HCPCS code

Coverage Summary

Initial Therapy Criteria

Initial therapy for X-linked hypophosphatemia (XLH)

Covered when ALL of the following are met:

ALL of the following

Diagnosis of XLH, confirmed by one of the following:
- Genetic testing (e.g., confirmed PHEX gene mutation in patient or first-degree relative)
- Elevated FGF23: Elevated Serum fibroblast growth factor 23 (FGF23) level > 30 pg/mL> 30 pg/mL
- Biochemical findings associated with XLH
  - Serum phosphate < 3.0 mg/dL (0.97 mmol/L)< 3.0 mg/dL (0.97 mmol/L)
  - Serum creatinine (SCr) below age adjusted upper limit of normal (ULN)below age-adjusted ULN
  - Serum 25(OH)D ≥ 16 ng/mL≥ 16 ng/mL
Additional initial criteria
- Age: Patient is age 6 months or greater≥ 6 months
- Prescriber: Prescribed by, or in consultation with, an endocrinologist or specialist experienced in the treatment of metabolic bone disorders
- Dosing is in accordance with the United States Food and Drug Administration approved labeling
- Authorization duration: Initial authorization will be for no more than 12 months≤ 12 months

Initial therapy for FGF23-related hypophosphatemia in tumor-induced osteomalacia (TIO)

Covered when ALL of the following are met:

ALL of the following

Diagnosis and disease status
- Diagnosis of TIO: Diagnosis of FGF23-related hypophosphatemia in TIO associated with phosphaturic mesenchymal tumors
- Unresectable or unlocalized disease: Disease cannot be curatively resected or localized
- Age: Patient is age 2 years or greater≥ 2 years
Prescriber and prior therapy

Continuation Therapy Criteria

Continuation (reauthorization) for XLH

Covered when ALL of the following are met:

Prior treatment: Patient has previously received treatment with burosumab
Clinical response: Patient has experienced a positive clinical response to burosumab (e.g., enhanced height velocity, improvement in skeletal deformities, reduction of fractures, reduction of generalized bone pain)
Prescriber: Prescribed by, or in consultation with, an endocrinologist or specialist experienced in the treatment of metabolic bone disorders
Dosing is in accordance with the United States Food and Drug Administration approved labeling
Reauthorization duration: Reauthorization will be for no more than 12 months≤ 12 months

Continuation (reauthorization) for FGF23-related hypophosphatemia in TIO

Covered when ALL of the following are met:

Continuation (reauthorization) for TIO

Prior treatment: Patient has previously received treatment with burosumab
Prescriber: Prescribed by, or in consultation with, an oncologist, an endocrinologist or specialist experienced in the treatment of metabolic bone disorders
Clinical response: Patient has experienced a positive clinical response to burosumab (e.g., enhanced height velocity, improvement in skeletal deformities, reduction of fractures, reduction of generalized bone pain)
Dosing is in accordance with the United States Food and Drug Administration approved labeling

Provider Actions & Prior Authorization

Prior Authorization

Initial prior authorization requirements

Initial prior authorization requires submission of documentation confirming the diagnosis (genetic testing OR elevated FGF23 > 30 pg/mL OR the specified biochemical panel for XLH), patient age criteria, prescriber specialty or consultation, baseline labs, and planned dosing per FDA labeling. Initial authorizations are limited to up to 12 months.

Affected code: J0584
Required labs/diagnosis proof: Genetic testing (e.g., PHEX mutation) OR serum FGF23 > 30 pg/mL OR serum phosphate < 3.0 mg/dL plus SCr below age-adjusted ULN and serum 25(OH)D ≥ 16 ng/mL
Prescriber: endocrinologist or specialist experienced in metabolic bone disorders
Dosing per FDA labeling; initial auth ≤ 12 months

Prior Authorization

Reauthorization requirements

For reauthorization, document prior receipt of burosumab and provide evidence of a positive clinical response to therapy. Reauthorization must also show continued prescriber specialty or consultation and dosing consistent with FDA labeling. Reauthorizations are limited to up to 12 months.

Affected code: J0584
Examples of positive clinical response: enhanced height velocity, improvement in skeletal deformities, reduction in fractures, reduction of generalized bone pain
Continued prescriber: endocrinologist, oncologist, or metabolic bone specialist
Dosing per FDA labeling; reauth ≤ 12 months

Documentation Required

Laboratory documentation

Provide the indicated laboratory studies with submitted requests. For TIO, supply a fasting serum phosphorus level that is below the normal range for age. For XLH, supply serum phosphate, serum creatinine demonstrating SCr below the age-adjusted upper limit of normal, and serum 25(OH)D ≥ 16 ng/mL as applicable.

Fasting serum phosphorus (TIO): below the normal range for age
Serum phosphate (XLH diagnostic threshold): < 3.0 mg/dL (0.97 mmol/L)
Serum creatinine (XLH): SCr below age-adjusted upper limit of normal (ULN)
Serum 25(OH)D (XLH): ≥ 16 ng/mL

Denial Risk

Medicare-specific prior therapy requirement

Medicare reviews may require documentation of prior failure, contraindication, or intolerance to vitamin D analog therapy in combination with an oral phosphate agent before coverage is approved under some Medicare‑Part‑B step therapy programs. Refer to Medicare‑Part‑B‑Step‑Therapy guidance as noted in the policy.

Per policy, prior therapy requirement: failure/contraindication/intolerance to vitamin D analog (e.g., calcitriol, paricalcitol, doxercalciferol) plus oral phosphate (e.g., K‑Phos, K‑Phos Neutra) may be required for Medicare reviews
See Medicare‑Part‑B‑Step‑Therapy‑Programs referenced in the policy

Clinical Evidence Summary

Pivotal pediatric phase 3 randomized data showed burosumab improved rickets versus conventional therapy with a RGI‑C global score difference of +1.1 (95% CI 0.8–1.5) favoring burosumab. In adults with XLH, a randomized trial reported 94% of burosumab patients achieved serum phosphorus above the lower limit of normal through week 24 compared with 8% for placebo. Single‑arm TIO studies demonstrated mean serum phosphorus increased toward the lower limit of normal with sustained effects and a variable proportion of patients achieving LLN across studies (50%–69%).

50%Proportion of TIO patients achieving mean serum phosphorus ≥LLN in Study NCT02304237 through Week 24

69%Proportion of TIO patients achieving mean serum phosphorus ≥LLN in Study NCT02722798 through Week 24

Background

Burosumab is a monoclonal agent that inhibits excess fibroblast growth factor 23 (FGF23), thereby normalizing serum phosphate. It is FDA‑approved for X‑linked hypophosphatemia (XLH) and for FGF23‑related hypophosphatemia in tumor‑induced osteomalacia (TIO). Conventional therapy historically consists of active vitamin D metabolites combined with oral phosphate supplementation.

Definitions to aid clinical interpretation:

- XLH: X‑linked hypophosphatemia, a heritable disorder of renal phosphate transport associated with elevated FGF23.

- TIO: Tumor‑induced osteomalacia, an acquired paraneoplastic syndrome causing FGF23‑mediated hypophosphatemia.

- LLN: Lower limit of normal.

Policy Summary

PayerUnitedHealthcare

PolicyCrysvita (burosumab-twza) for X-linked hypophosphatemia and FGF23-related hypophosphatemia in tumor-induced osteomalacia

Policy CodePolicy 2025D0071N

Change TypeTemplate Update (07/01/2025)

Effective DateMay 1, 2025

Next Review Date

On This Page

E83.31	Familial hypophosphatemia
M83.8	Other adult osteomalacia

OpenPayer

Crysvita (burosumab-twza) for X-linked hypophosphatemia and FGF23-related hypophosphatemia in tumor-induced osteomalacia

Coverage Summary

Initial Therapy Criteria

Continuation Therapy Criteria

Applicable Codes

Provider Actions & Prior Authorization

Clinical Evidence Summary

Background

Revision History