ModifiedUnitedHealthcarePolicy CS2026D0071Q

Crysvita (burosumab) — Medical Benefit Drug Policy (XLH and TIO)

Medical benefit drug policy describing coverage criteria for burosumab (Crysvita) for treatment of X-linked hypophosphatemia (XLH) and FGF23-related hypophosphatemia in tumor-induced osteomalacia (TIO) for UnitedHealthcare members.

Policy Summary

PayerUnitedHealthcare

PolicyCrysvita (burosumab) — Medical Benefit Drug Policy (XLH and TIO)

Policy CodePolicy CS2026D0071Q

Change TypeNon‑material housekeeping and archival of prior version

Effective DateApr 1, 2026

Next Review Date

Key ActionSubmit prior authorization with documentation of age, diagnostic confirmation, required biochemical criteria, specialist involvement, and dosing per FDA labeling; initial and reauthorization approvals are limited to up to 12 months.

SourceLink

POLICY UPDATE CHANGES

Removed language indicating this Medical Benefit Drug Policy does not apply to the state of Indiana and removed content/language pertaining to the state of Louisiana.

Archived previous policy version CS2025D0071P.

12 monthsmaximum initial or reauthorization duration

J0584listed HCPCS code for burosumab

6 months+FDA-indicated lower age for XLH treatment

2 years+FDA-indicated lower age for TIO treatment

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<3.0 mg/dLbiochemical criterion cited for XLH

1Archived prior policy referenced

Coverage Criteria for Crysvita (burosumab)

Initial Therapy (XLH)

Covered when ALL of the following are met:

XLH diagnostic criteria: Diagnosis of X-linked hypophosphatemia (XLH) confirmed by one of: genetic testing showing a PHEX gene mutation in the patient or a first-degree relative; OR elevated serum FGF23 > 30 pg/mL; OR all of the following biochemical findings: serum phosphate < 3.0 mg/dL (0.97 mmol/L) AND serum creatinine below the age-adjusted upper limit of normal (ULN) AND serum 25(OH)D >= 16 ng/mL.see text

from policy

Prescriber, labs, dosing, and authorization: Prescribed by, or in consultation with, an endocrinologist or specialist experienced in metabolic bone disorders; fasting serum phosphorus is below the normal range for age; dosing in accordance with U.S. FDA‑approved labeling; initial authorization limited to no more than 12 months.see text

from policy

Continuation Therapy (XLH)

Covered when ALL of the following are met:

XLH continuation criteria: Patient has previously received treatment with burosumab; prescribed by, or in consultation with, an endocrinologist or specialist experienced in metabolic bone disorders; patient has experienced a positive clinical response to burosumab (examples include enhanced height velocity, improvement in skeletal deformities, reduction of fractures, reduction of generalized bone pain); dosing in accordance with U.S. FDA‑approved labeling; reauthorization limited to no more than 12 months.see text

from policy

Initial Therapy (TIO)

Covered when ALL of the following are met:

TIO diagnostic and prior therapy requirements: Diagnosis of FGF23‑related hypophosphatemia in tumor‑induced osteomalacia (TIO) associated with phosphaturic mesenchymal tumors; disease cannot be curatively resected or localized; patient is age 2 years or greater; prescribed by, or in consultation with, an oncologist, an endocrinologist, or a specialist experienced in metabolic bone disorders; history of failure, contraindication, or intolerance to vitamin D analog therapy (e.g., calcitriol, paricalcitol, doxercalciferol) in combination with an oral phosphate agent (e.g., K‑Phos®, K‑Phos Neutra®); fasting serum phosphorus is below the normal range for age; dosing in accordance with U.S. FDA‑approved labeling; initial authorization limited to no more than 12 months.see text

from policy

Continuation Therapy (TIO)

Covered when ALL of the following are met:

TIO continuation criteria: Patient has previously received treatment with burosumab; prescribed by, or in consultation with, an oncologist, an endocrinologist, or a specialist experienced in metabolic bone disorders; patient has experienced a positive clinical response to burosumab (examples include improvement in skeletal deformities, reduction of fractures, reduction of generalized bone pain); dosing in accordance with U.S. FDA‑approved labeling; reauthorization limited to no more than 12 months.see text

from policy

This Medical Benefit Drug Policy does not apply to the states listed in the policy application section. Refer to the state-specific policy or guideline as noted for: Florida (refer to the state's Medicaid clinical policy), Kansas, North Carolina, Ohio (Crysvita® (Burosumab-Twza) for Ohio Only), Pennsylvania (Crysvita® (Burosumab-Twza) for Pennsylvania Only), and Texas (refer to drug-specific criteria in the Texas Medicaid Provider Procedures Manual).

FDA approval or labeling information is provided for informational purposes only. FDA approval alone is not a basis for coverage; coverage determinations are made according to the criteria and plan, federal, or state contractual requirements described in this policy.

Requests for burosumab that do not meet all required criteria are not supported as medically necessary. Examples include absence of confirmed diagnostic criteria (e.g., no genetic confirmation of XLH, no elevated FGF23 > 30 pg/mL, or missing XLH biochemical profile), patient age below the policy-specified thresholds (XLH: < 6 months for FDA indication; TIO: < 2 years), fasting serum phosphorus not below the normal range for age or serum phosphate not meeting the XLH threshold (< 3.0 mg/dL when applicable), lack of required prior therapy for TIO (no trial of vitamin D analog plus oral phosphate or documented contraindication/intolerance), prescriber not an appropriate specialist or lack of documented specialist consultation, or dosing not consistent with the United States FDA–approved labeling. Such deficiencies may result in denial.

Coding and Diagnostic Codes

HCPCS codesHCPCS

J0584

Injection, burosumab-twza, 1 mg

ICD-10 diagnosis codes (examples listed)ICD-10

E83.31	Familial hypophosphatemia
M83.8	Other adult osteomalacia

Serum phosphate — XLH diagnostic biochemical threshold

Diagnostic biochemical thresholdFasting serum phosphate (serum phosphorus) < 3.0 mg/dL (0.97 mmol/L)

Additional required labs for XLH initial diagnosisSerum creatinine below age‑adjusted upper limit of normal and serum 25(OH)D ≥ 16 ng/mL

Alternative diagnostic confirmationElevated serum FGF23 > 30 pg/mL or PHEX gene mutation in patient or first‑degree relative

Prior Authorization & Provider Requirements

Prior Authorization

Prior Authorization Required

Prior authorization is required for burosumab (Crysvita) under this policy. Requests should include complete clinical documentation to support the diagnosis, prior treatments, and medical necessity. Initial authorizations are limited to a maximum of 12 months; reauthorizations are also limited to 12 months.

Prior authorization required for both XLH and TIO indications
Initial and reauthorization durations: up to 12 months

Step Therapy

Step Therapy for TIO

Step therapy requirement for tumor-induced osteomalacia (TIO): a documented trial with documented failure, contraindication, or intolerance to a vitamin D analog in combination with an oral phosphate agent is required prior to approval of burosumab for TIO.

Required trial: vitamin D analog (e.g., calcitriol, paricalcitol, doxercalciferol) PLUS oral phosphate (e.g., K-Phos®, K-Phos Neutra®)
Documented failure, contraindication, or intolerance must be provided

Background and Clinical Context

X-linked hypophosphatemia (XLH) is a heritable disorder of renal phosphate transport characterized by renal phosphate wasting, hypophosphatemia, and elevated fibroblast growth factor 23 (FGF23), which leads to impaired bone mineralization. In children, XLH commonly presents with rickets and impaired linear growth; in adults it is associated with osteomalacia, bone pain, fractures, and reduced mobility. Tumor-induced osteomalacia (TIO) is an acquired paraneoplastic syndrome caused by phosphaturic mesenchymal tumors that ectopically secrete FGF23, producing biochemical and bone abnormalities similar to genetic hypophosphatemia. Treatment goals differ by age: in children the aim is to correct or minimize rickets and improve growth, while in adults the focus is symptomatic management including reduction of bone pain and fracture risk. Burosumab (Crysvita) is an FGF23-blocking monoclonal antibody approved for XLH (patients aged 6 months and older) and for FGF23-related hypophosphatemia in TIO when tumors cannot be curatively resected or localized (patients aged 2 years and older); policy coverage is guided by the diagnostic, biochemical, prescriber, prior-therapy, and dosing criteria specified in this document.

Definitions

X-linked hypophosphatemia (XLH) — definition and clinical features

DefinitionHeritable disorder of renal phosphate transport leading to hypophosphatemia, elevated FGF23, and impaired bone mineralization

Key pediatric clinical featuresRickets and impaired linear growth; radiographic rickets/osteomalacia that treatment aims to correct or minimize

Key adult clinical featuresOsteomalacia, bone pain, fractures or pseudofractures, mobility limitations; treatment focused on symptom management and fracture healing

Diagnostic considerationsConfirmed by PHEX mutation in patient or first‑degree relative, or elevated FGF23 > 30 pg/mL, or biochemical profile including serum phosphate < 3.0 mg/dL

Tumor-induced osteomalacia (TIO) — definition and clinical features

Definition

Policy Revision History

2026-04-01state_applicability_editLatest

Removed language indicating the policy does not apply to the state of Indiana and removed content related to Louisiana.

2026-04-01archived_prior_version

Archived previous policy version CS2025D0071P.

Policy Summary

PayerUnitedHealthcare

PolicyCrysvita (burosumab) — Medical Benefit Drug Policy (XLH and TIO)

Policy CodePolicy CS2026D0071Q

Change TypeNon‑material housekeeping and archival of prior version

Effective DateApr 1, 2026

Next Review Date

SourceLink

On This Page

Documentation Required

Required Clinical Documentation

Required clinical documentation — include diagnostic confirmation and objective biochemical and imaging data. Lack of adequate documentation is a common reason for denial.

Genetic testing confirming PHEX mutation in patient or first-degree relative, OR elevated serum FGF23 > 30 pg/mL, OR biochemical criteria consistent with XLH (serum phosphate < 3.0 mg/dL, age‑adjusted normal SCr, serum 25(OH)D ≥ 16 ng/mL)
For TIO: documentation of phosphaturic mesenchymal tumor that cannot be localized or resected
Fasting serum phosphorus below the normal range for age
Relevant biochemical tests (serum phosphate, creatinine, 25(OH)D, FGF23 where available)
Consultation notes showing prescription by or in consultation with an endocrinologist, oncologist, or metabolic bone specialist as specified
Documentation of prior therapies (e.g., vitamin D analog + oral phosphate) when applicable, and objective evidence of prior treatment response for continuation requests (height velocity, fracture history, pain improvement, radiographic findings)

Denial Risk

Denial Triggers

Common denial triggers — requests may be denied if the required diagnostic, biochemical, specialty prescriber, dosing, age, or prior‑therapy criteria are not met or documented.

Absence of confirmed XLH diagnosis (no genetic test, elevated FGF23, or qualifying biochemical profile)
Missing or normal fasting serum phosphorus for age
Prescriber is not the required specialist and no consultation documentation provided
Dosing inconsistent with FDA‑approved labeling
For TIO: lack of documentation of prior vitamin D analog + oral phosphate trial (or documented contraindication/intolerance)
Patient below the minimum age for the indication (TIO requires age ≥ 2 years)

Note

Coverage Governance & Reference Documents

Coverage decisions are governed by the member's specific benefit plan and applicable federal, state, or contractual requirements. When plan terms differ from this policy, the federal, state, or contractual requirements control.

Reference the member's benefit plan and any federal/state/contractual requirements when making coverage determinations
This policy is informational and may be supplemented by plan‑level rules or third‑party tools (e.g., InterQual®)

Rare acquired paraneoplastic syndrome caused by phosphaturic mesenchymal tumors that ectopically secrete FGF23, leading to hypophosphatemia and osteomalacia

Tumor characteristicsTypically benign, small, slow‑growing mesenchymal tumors that produce phosphaturic factors (including FGF23)

Clinical biochemistryElevated circulating FGF23 levels with biochemical and bone mineralization abnormalities resembling genetic hypophosphatemia

Treatment implicationTIO requires demonstration that the tumor cannot be curatively resected or localized before systemic therapy is considered

Crysvita (burosumab) — product and indicated ages

Product descriptionCrysvita (burosumab) is a monoclonal antibody that blocks fibroblast growth factor 23 (FGF23), resulting in normalization of serum phosphate

FDA‑indicated ages — XLHIndicated for treatment of X‑linked hypophosphatemia (XLH) in adult and pediatric patients 6 months of age and older

FDA‑indicated ages — TIOIndicated for treatment of FGF23‑related hypophosphatemia in tumor‑induced osteomalacia (TIO) in adult and pediatric patients 2 years of age and older (when tumor cannot be curatively resected or localized)

Mechanism of benefitInhibits excess FGF23 to increase serum phosphate and improve bone mineralization and related clinical outcomes