Currentsierra health and lifePolicy 2026D0071O

Crysvita (burosumab-twza) — Coverage Criteria for X-linked hypophosphatemia (XLH) and FGF23-related hypophosphatemia in TIO

This policy governs medical necessity criteria, prior authorization, and coding for Crysvita (burosumab-twza) for treatment of X-linked hypophosphatemia (XLH) and FGF23-related hypophosphatemia in tumor-induced osteomalacia (TIO) for applicable UnitedHealthcare commercial and individual exchange plans.

Policy Summary

Payersierra health and life

PolicyCrysvita (burosumab-twza) — Coverage Criteria for XLH and TIO

Policy CodePolicy 2026D0071O

Change TypeTemplate updateapplied to UnitedHealthcare Commercial & Individual Exchange

Effective DateMay 1, 2026

Next Review Date

Key ActionSubmit prior authorization with diagnostic confirmation and required labs; initial and reauthorizations are limited to 12 months.

SourceLink

POLICY UPDATE CHANGES

Policy transferred to shared template and applied to UnitedHealthcare Commercial and Individual Exchange plans; prior authorization requirements follow the member-specific plan.

No material clinical or coverage changes beyond template update were identified in this revision.

12 monthsmax auth period

J0584HCPCS

≥6 monthsmin age (XLH)

≥2 yearsmin age (TIO)

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Coverage Criteria for Crysvita (burosumab-twza)

Initial Therapy (XLH)

Covered when ALL of the following are met for initial XLH therapy

XLH initial therapy criteria: Patient age 6 months or greater; diagnosis of X-linked hypophosphatemia (XLH) confirmed by one of the following: genetic testing (e.g., confirmed 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); serum creatinine below age‑adjusted upper limit of normal; serum 25(OH)D ≥ 16 ng/mL; prescribed by, or in consultation with, an endocrinologist or specialist experienced in metabolic bone disorders; fasting serum phosphorus below the normal range for age; dosing in accordance with FDA‑approved labeling; initial authorization for no more than 12 months.see node text

From policy initial therapy section

Continuation Therapy (XLH)

Covered when ALL of the following are met for continuation (XLH)

XLH continuation criteria: Patient has previously received 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 (for example: enhanced height velocity, improvement in skeletal deformities, reduction of fractures, reduction of generalized bone pain); dosing in accordance with FDA‑approved labeling; reauthorization for no more than 12 months.see node text

From policy continuation section

Initial Therapy (TIO)

Covered when ALL of the following are met for initial TIO therapy

TIO initial therapy criteria: 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 below the normal range for age; dosing in accordance with FDA‑approved labeling; initial authorization for no more than 12 months.see node text

From policy TIO initial therapy section

Continuation Therapy (TIO)

Covered when ALL of the following are met for continuation (TIO)

TIO continuation criteria: Patient has previously received 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 (e.g., improved skeletal findings, reduced fractures or bone pain); dosing in accordance with FDA‑approved labeling; reauthorization for no more than 12 months.see node text

From policy TIO continuation section

This policy summarizes the clinical coverage framework for Crysvita (burosumab-twza) in FGF23-mediated hypophosphatemic disorders. It defines the medical necessity expectations for initial and continuation therapy in X-linked hypophosphatemia (XLH) and for initial and continuation therapy in tumor‑induced osteomalacia (TIO). The policy aligns coverage determinations with documented diagnosis, age thresholds, biochemical data, prescriber specialty involvement, and dosing consistent with the FDA label. References to member-specific benefit plan terms, federal or state mandates, and Medicare program requirements are incorporated where applicable.

FDA approval and the drug’s labeled indications are provided here for informational context only. FDA approval alone is not a basis for coverage; coverage decisions require that the member’s clinical presentation and submitted documentation meet the policy’s medical necessity criteria and any applicable member benefit or regulatory requirements.

Coverage decisions under this policy depend on the documentation supplied and the member’s specific benefit terms. Providers must submit the clinical records and laboratory data specified in the coverage criteria; requests lacking the required diagnostic confirmation, relevant labs, or documentation of prior therapy where required may be denied. The inclusion of procedure or diagnosis codes in this policy is for reference only and does not guarantee coverage or payment—always verify the member’s benefit document and any applicable state mandates before assuming coverage.

Coding and Billing Codes

Covered HCPCSHCPCSCovered

J0584

Injection, burosumab-twza, 1 mg

Relevant diagnosis codes (reference)ICD-10

E83.31	Familial hypophosphatemia
M83.8	Other adult osteomalacia

inv-10: Serum phosphate — biochemical threshold value used in criteria

Serum phosphate thresholdFasting serum phosphate < 3.0 mg/dL (0.97 mmol/L)

Supporting lab contextUsed as part of biochemical criteria for initial XLH diagnosis when genetic testing or elevated FGF23 not available

Clinical trial concordanceClinical studies enrolled children with fasting serum phosphorus lower than 0.97 mmol/L (3.0 mg/dL)

Provider Actions, Prior Authorization, and Documentation

Prior Authorization

Prior Authorization Required

Prior authorization is required for initiation of burosumab (Crysvita). Initial and reauthorization approvals are limited to no more than 12 months.

Initial authorization: ≤ 12 months
Reauthorization: ≤ 12 months
Dosing must follow FDA labeling

Denial Risk

Medicare Part B and CMS Compliance

For Medicare Advantage reviews, ensure compliance with Medicare Part B/NCDs/LCDs/LCAs where applicable. Part B rules (including "incident to" requirements and whether a drug is usually self‑administered) may affect coverage. Preferred therapy criteria may be governed by Medicare Part B step therapy programs — consult CMS guidance and the Medicare Advantage Medical Policy as needed.

Background and Clinical Context

X-linked hypophosphatemia (XLH) is a heritable renal phosphate‑wasting disorder caused by elevated FGF23, resulting in chronic hypophosphatemia and impaired bone mineralization. The therapeutic mechanism of burosumab is neutralization of excess FGF23 to increase renal phosphate reabsorption and raise serum phosphate toward age‑appropriate ranges. In children the treatment goal focuses on correction of rickets and improved growth velocity; in adults the focus is on reducing bone pain, improving mobility, and promoting fracture or pseudofracture healing. For tumor‑induced osteomalacia (TIO), burosumab is used when the phosphaturic tumor cannot be localized or curatively resected and the patient has FGF23‑mediated hypophosphatemia.

Definitions

inv-20: XLH — Definition of X-linked hypophosphatemia (FGF23-mediated disorder)

DefinitionX-linked hypophosphatemia (XLH) is a heritable disorder of renal phosphate transport associated with elevated serum FGF23 and resulting hypophosphatemia and abnormal bone mineralization.

PathophysiologyElevated FGF23 causes renal phosphate wasting and low serum phosphate, leading to rickets/osteomalacia in children and bone pain or fractures in adults.

Diagnostic cluesDiagnosis may be confirmed by PHEX gene mutation in the patient or a first-degree relative, elevated FGF23, or characteristic biochemical findings including low serum phosphate.

inv-21: TIO — Definition of Tumor-induced osteomalacia (FGF23-related hypophosphatemia due to tumor)

DefinitionTumor-induced osteomalacia (TIO) is an acquired paraneoplastic syndrome in which phosphaturic mesenchymal tumors ectopically produce FGF23, causing FGF23-related hypophosphatemia and impaired bone mineralization.