CurrentUnitedHealthcarePolicy CSLA2025D0071N

Crysvita (Burosumab) — Medical Benefit Drug Policy (Louisiana)

Defines medical benefit drug coverage criteria for burosumab (Crysvita) for treatment of X-linked hypophosphatemia (XLH) and FGF23-related hypophosphatemia in tumor-induced osteomalacia (TIO) for UnitedHealthcare Community Plan in Louisiana.

Policy Summary

PayerUnitedHealthcare

PolicyCrysvita (Burosumab) — Medical Benefit Drug Policy (Louisiana)

Policy CodePolicy CSLA2025D0071N

Change TypeRoutine review — no change to coverage guidelines

Effective DateMay 1, 2025

Next Review Date

Key ActionObtain prior authorization demonstrating diagnosis confirmation, required biochemical tests, age and prior therapy where applicable, and include HCPCS code J0584 on claims.

SourceLink

POLICY UPDATE CHANGES

Routine review; no change to coverage guidelines.

2indications covered (XLH, TIO)

12max authorization interval (months)

J0584HCPCS

≥6m / ≥2yminimum ages (XLH / TIO)

Coverage Criteria for Crysvita (burosumab)

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Initial Therapy — XLH

Covered when ALL of the following are met

XLH initial therapy: Diagnosis of X-linked hypophosphatemia (XLH) confirmed by ONE of: genetic testing (e.g., confirmed PHEX gene mutation in patient or 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), serum creatinine below age‑adjusted upper limit of normal (ULN), and serum 25(OH)D ≥ 16 ng/mL; AND patient is age ≥ 6 months; AND one of the following regarding growth plates: epiphyseal plate has not fused; OR ALL of the following: epiphyseal plate has fused; AND patient is experiencing clinical signs/symptoms (e.g., limited mobility, musculoskeletal pain, bone fractures); AND 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®); AND prescribed by, or in consultation with, an endocrinologist or specialist experienced in the treatment of metabolic bone disorders; AND fasting serum phosphorus is below the normal range for age; AND dosing is in accordance with the United States Food and Drug Administration approved labeling; AND initial authorization will be for no more than 12 months.

Continuation Therapy — XLH

Covered when ALL of the following are met

XLH continuation therapy: Patient has previously received treatment with burosumab; AND prescribed by, or in consultation with, an endocrinologist or specialist experienced in the treatment of metabolic bone disorders; AND 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); AND dosing is in accordance with the United States Food and Drug Administration approved labeling; AND reauthorization will be for no more than 12 months.

Initial Therapy — TIO

Covered when ALL of the following are met

TIO initial therapy: Diagnosis of FGF23‑related hypophosphatemia in tumor‑induced osteomalacia (TIO) associated with phosphaturic mesenchymal tumors; AND disease cannot be curatively resected or localized; AND patient is age ≥ 2 years; AND prescribed by, or in consultation with, an oncologist, an endocrinologist, or specialist experienced in the treatment of metabolic bone disorders; AND 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®); AND fasting serum phosphorus is below the normal range for age; AND dosing is in accordance with the United States Food and Drug Administration approved labeling; AND initial authorization will be for no more than 12 months.

Continuation Therapy — TIO

Covered when ALL of the following are met

TIO continuation therapy: Patient has previously received treatment with burosumab; AND prescribed by, or in consultation with, an oncologist, an endocrinologist, or specialist experienced in the treatment of metabolic bone disorders; AND 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); AND dosing is in accordance with the United States Food and Drug Administration approved labeling; AND reauthorization will be for no more than 12 months.

No exclusions are explicitly listed in the COVERAGE CRITERIA section of this policy.

This portion of the policy does not include any explicit statements declaring services or uses as not medically necessary.

Coding and Diagnostic Criteria

Procedure CodesHCPCS

J0584

Injection, burosumab-twza, 1 mg.

Diagnosis Codes (examples listed)ICD-10

E83.31	Familial hypophosphatemia
M83.8	Other adult osteomalacia

inv-09: Serum phosphate — < 3.0 mg/dL (0.97 mmol/L) for diagnostic biochemical finding

Diagnostic thresholdSerum phosphate < 3.0 mg/dL (0.97 mmol/L)

Context of useUsed as a biochemical finding supporting diagnosis of XLH when combined with other criteria (SCr below age‑adjusted ULN and 25(OH)D ≥ 16 ng/mL)

Clinical trial relevanceFasting serum phosphorus < 3.0 mg/dL was an entry criterion in pediatric burosumab trials (children 1–12 years)

inv-10: Elevated FGF23 — > 30 pg/mL

Diagnostic thresholdElevated serum FGF23 > 30 pg/mL

Role in diagnosisOne of the accepted methods to confirm XLH in initial therapy criteria (alternatively genetic confirmation or characteristic biochemistry)

Policy useUsed as objective laboratory evidence of FGF23-mediated hypophosphatemia to support coverage

inv-11: Target fasting serum phosphorus for dosing in trials — 3.5 to 5.0 mg/dL (used in pediatric dosing titration in clinical studies)

Target range used in trialsTarget fasting serum phosphorus for pediatric dosing titration: 3.5 to 5.0 mg/dL

ApplicationRange used to guide dosing adjustments in pediatric clinical studies of burosumab

Measurement contextFasting serum phosphorus values referenced in trial inclusion and outcome assessments

Provider Actions, Prior Authorization & Documentation

Prior Authorization

Prior Authorization Required

Prior authorization is required. Requests must demonstrate the applicable indication-specific criteria (diagnosis confirmation, relevant biochemical abnormalities, age limits, prescriber specialty, and dosing consistent with FDA labeling). Initial authorizations are limited to no more than 12 months; reauthorizations (continuation) are limited to no more than 12 months and require evidence of prior benefit from therapy.

Affected drug: burosumab (Crysvita) — J0584
Initial authorization: ≤ 12 months; Reauthorization: ≤ 12 months
Required demonstration: diagnosis confirmation (genetic testing, elevated FGF23, or biochemical profile), fasting serum phosphorus below age-normal range, age criteria (≥ 6 months for XLH; ≥ 2 years for TIO where applicable), and prescriber specialty

Note

Use with Plan-Specific Prior Authorization

This policy is intended to assist in interpreting UnitedHealthcare standard benefit plans but does not replace federal, state, or contractual benefit plan requirements. Plan-specific prior authorization processes and formularies may impose additional requirements or limitations that must be followed.

Verify and follow any plan-specific prior authorization forms, portals, or additional criteria
When plan language conflicts with this policy, the federal/state/contractual requirements govern

Denial Risk

Potential Denial Triggers

Coverage may be denied if required documentation or criteria are not met. Common denial triggers include missing or insufficient diagnostic confirmation, absent biochemical evidence (e.g., fasting serum phosphorus), lack of prior therapy documentation where required, incorrect prescriber specialty, or dosing inconsistent with FDA labeling.

No genetic testing or alternative diagnostic confirmation (e.g., elevated FGF23 or required biochemical profile)
Fasting serum phosphorus not documented as below age-specific normal range
No documentation of failure, contraindication, or intolerance to required prior therapy (vitamin D analog + oral phosphate) when applicable
Prescriber is not an endocrinologist, oncologist, or specialist experienced in metabolic bone disorders (or no documented consultation)
Dosing requests outside FDA-approved labeling

Documentation Required

Required Documentation

Required documentation must be submitted with the prior authorization request to support medical necessity, including diagnostic, biochemical, treatment history, and prescriber information.

Diagnostic confirmation: genetic testing showing PHEX mutation in patient or first-degree relative, or elevated serum FGF23 (> 30 pg/mL), or biochemical profile consistent with XLH
Biochemical evidence: serum phosphate (including fasting value) below age-adjusted normal range, serum creatinine below age-adjusted ULN, serum 25(OH)D ≥ 16 ng/mL where specified
Age and growth/epiphyseal status documentation (e.g., age ≥ 6 months for XLH; epiphyseal plate status if relevant)
Prior therapy documentation: evidence of failure, contraindication, or intolerance to vitamin D analog therapy combined with an oral phosphate agent when step therapy is required
Prescriber attestation: prescription by or documentation of consultation with an endocrinologist, oncologist, or metabolic bone disorder specialist
Clinical response for continuation: documentation of positive clinical response to burosumab (e.g., improved height velocity, reduced fractures or bone pain, improved skeletal deformities)

Note

Plan Requirements Verification

Verify federal, state, and contractual plan requirements prior to submitting requests. Coverage determinations must conform to governing benefit language; this policy supplements but does not override those requirements.

Confirm any state-mandated coverage or age limits and any emergency or continuity-of-care provisions
Ensure submitted documentation aligns with the member's specific benefit plan terms

Step Therapy

Step Therapy / Prior Treatment Requirement

Step therapy / prior treatment requirement: For members who meet indication-specific criteria, a history of failure, contraindication, or intolerance to vitamin D analog therapy in combination with an oral phosphate agent is required when specified in the indication (e.g., XLH patients with fused epiphyses or TIO patients).

Document attempts and outcomes of prior vitamin D analog + oral phosphate therapy (dates, dosages, reasons for discontinuation)
If step therapy is waived due to contraindication or intolerance, include supporting clinical documentation

Background and Clinical Context

X-linked hypophosphatemia (XLH) is a heritable disorder of renal phosphate transport characterized by elevated fibroblast growth factor 23 (FGF23), resulting in hypophosphatemia and defective bone mineralization; treatment goals differ by age (for example, correction of rickets in children and management of pain and mobility in adults). Tumor-induced osteomalacia (TIO) is an acquired, FGF23-mediated paraneoplastic syndrome caused by phosphaturic mesenchymal tumors that produce FGF23 and cause similar biochemical and skeletal abnormalities as XLH.

Burosumab (Crysvita) is a monoclonal antibody that blocks FGF23, normalizes serum phosphate, and is indicated for treatment of XLH in patients aged ≥ 6 months and for FGF23-related hypophosphatemia in TIO in patients aged ≥ 2 years. Clinical use and coverage decisions in this policy reference diagnostic criteria (genetic confirmation or elevated FGF23 or characteristic biochemical profile), age thresholds, prior therapy requirements for certain populations, and dosing consistent with FDA labeling.

Definitions

inv-21: Confirmed XLH — Diagnosis confirmed by PHEX gene mutation in patient or first-degree relative, or elevated serum FGF23 > 30 pg/mL, or characteristic bioc...

DefinitionConfirmed XLH: diagnosis established by PHEX gene mutation in patient or first‑degree relative, OR elevated serum FGF23 > 30 pg/mL, OR characteristic biochemical findings (serum phosphate < 3.0 mg/dL, SCr below age‑adjusted ULN, 25(OH)D ≥ 16 ng/mL)

Age considerationPolicy covers XLH treatment in patients aged ≥ 6 months (FDA‑labeled population)

Clinical implicationConfirmation may be by genetic testing, laboratory demonstration of elevated FGF23, or supporting biochemical profile as listed above

inv-22: TIO (FGF23-related hypophosphatemia) — Hypophosphatemia caused by phosphaturic mesenchymal tumors that cannot be curatively resected or localized, with fasting serum phosphorus...

DefinitionTIO (FGF23‑related hypophosphatemia): hypophosphatemia caused by phosphaturic mesenchymal tumors that cannot be curatively resected or localized, with fasting serum phosphorus below the normal range for age

Treatment contextPolicy requires history of failure, contraindication, or intolerance to vitamin D analog plus oral phosphate for initial burosumab coverage in TIO

Prescriber requirementPrescribed by or in consultation with an oncologist, endocrinologist, or metabolic bone specialist for TIO patients

inv-23: osteomalacia-associated mesenchymal tumors — Comprehensive review and case analysis of osteomalacia-associated mesenchymal tumors supports that most are a single histopathologic entity.

Key conclusionMost osteomalacia‑associated mesenchymal tumors are a single histopathologic entity based on comprehensive review and case analysis

ReferencePolicy cites Folpe et al., Am J Surg Pathol. 2004;28(1):1–30 for this conclusion

RelevanceSupports grouping of mesenchymal tumors associated with osteomalacia/TIO in clinical considerations

inv-24: tumor-induced osteomalacia — Clinical and basic studies on tumor-induced osteomalacia provide foundational knowledge referenced by the policy.

ScopeTumor‑induced osteomalacia: clinical and basic studies describe tumor secretion of FGF23 and other phosphaturic proteins leading to hypophosphatemia and osteomalacia

Clinical featuresTIO tumors are often small, benign, slow‑growing phosphaturic mesenchymal tumors expressing FGF23; most patients have increased circulating FGF23

Supporting literaturePolicy references Shane et al., J Bone Miner Res. 1997 and other studies as foundational knowledge

OpenPayer

Crysvita (Burosumab) — Medical Benefit Drug Policy (Louisiana)

Coverage Criteria for Crysvita (burosumab)

Coding and Diagnostic Criteria

Provider Actions, Prior Authorization & Documentation

Background and Clinical Context

Definitions

Policy Revision History