Crysvita (Burosumab-Twza) (for Louisiana Only)
Medical benefit drug policy governing coverage criteria for burosumab (Crysvita) for treatment of X-linked hypophosphatemia (XLH) and FGF23-related hypophosphatemia in tumor-induced osteomalacia (TIO) for UnitedHealthcare Louisiana membership.
Policy retired and Louisiana plan membership disenrolled on Apr. 1, 2026.
Routine review on 05/01/2025 resulted in no change to coverage guidelines.
Routine review; no change to coverage guidelines.
Policy retired for Louisiana plan membership disenrolled on Apr. 1, 2026.
Coverage Criteria for Crysvita (burosumab)
Initial Therapy — X-linked hypophosphatemia (XLH)
Covered when ALL of the following are met
All conditions are required; dosing must follow FDA labeling.
Continuation Therapy — X-linked hypophosphatemia (XLH)
Covered when ALL of the following are met
All conditions required for reauthorization.
Initial Therapy — Tumor-induced osteomalacia (TIO)
Covered when ALL of the following are met
All conditions required.
Continuation Therapy — Tumor-induced osteomalacia (TIO)
Covered when ALL of the following are met
All conditions required for reauthorization.
No additional programmatic exclusions are specified beyond the coverage criteria and age limits detailed in this policy. The policy’s coverage rationale and criteria reference the U.S. Food and Drug Administration (FDA) approved indications for informational purposes: Crysvita (burosumab) is indicated for treatment of X-linked hypophosphatemia (XLH) in patients 6 months of age and older and for FGF23-related tumor-induced osteomalacia (TIO) in patients 2 years of age and older. Coverage under this medical policy is determined by whether the patient meets the specific diagnostic, biochemical, age, prior-therapy, prescriber, and dosing criteria described in the coverage sections, not by FDA approval alone.
This policy has been retired for Louisiana membership. Operationally, Louisiana plan membership was disenrolled effective April 1, 2026. See Policy History for the retirement entry and date.
Use of burosumab that does not meet all of the policy’s stated requirements will be considered not medically necessary. Required elements include, as applicable, documented diagnostic confirmation (e.g., genetic confirmation of PHEX mutation or elevated serum FGF23 for XLH; confirmed FGF23-related TIO), the biochemical criteria (e.g., serum phosphate < 3.0 mg/dL for XLH or fasting serum phosphorus below the normal range for age), specified age thresholds (XLH ≥ 6 months; TIO ≥ 2 years), prior trial/failure/contraindication/intolerance to vitamin D analog plus oral phosphate when required, prescribing specialist involvement, and dosing consistent with FDA labeling. Absent documentation of these requirements, prior authorization requests or claims may be denied.
Coding and Diagnostic Examples
| J0584 | Injection, burosumab-twza, 1 mg |
| E83.31 | Familial hypophosphatemia |
| M83.8 | Other adult osteomalacia |
Provider Actions, Prior Authorization and Documentation
Prior Authorization Required
Prior authorization is required for burosumab (Crysvita). Initial authorization and any reauthorization approvals will be granted for no more than 12 months.
- Initial and reauthorization approvals limited to a maximum of 12 months
Required Documentation to Support Medical Necessity
Document diagnostic confirmation of the condition being treated (e.g., XLH or FGF23-related tumor-induced osteomalacia), biochemical evidence, prior therapy history, prescriber specialty, and dosing records to support medical necessity.
- Diagnosis confirmation: genetic testing (e.g., PHEX mutation) or elevated FGF23 where applicable
- Biochemical evidence: serum phosphate, serum creatinine, serum 25(OH)D, fasting serum phosphorus as appropriate
- Prior therapy history: failure/contraindication/intolerance to vitamin D analog plus oral phosphate where required (TIO)
- Prescriber: prescribed by or in consultation with relevant specialist (oncologist, endocrinologist, or metabolic bone disorder specialist)
- Dosing: records showing dosing consistent with FDA-approved labeling
Potential Denial Triggers
Claims may be denied if required diagnostic, biochemical, or prior therapy documentation is missing or incomplete. Common denial triggers include absence of genetic testing or other diagnostic confirmation, no biochemical values demonstrating hypophosphatemia or appropriate renal function, or lack of documented trial and failure (or contraindication/intolerance) to required prior therapies.
- Missing diagnostic confirmation (e.g., no genetic test or FGF23 result)
- Absent or out-of-range biochemical data (e.g., serum phosphate, serum creatinine, 25(OH)D)
- No documentation of prior vitamin D analog + oral phosphate therapy trial when required (TIO)
- Prescriber specialty not documented or lack of consultation with an appropriate specialist
Check Governing Benefit Requirements
Before applying this policy to coverage decisions, verify the member’s governing benefit terms. Federal, state, or contractual plan requirements may differ from this standard policy and will govern in the event of a conflict.
- Check the member’s federal, state, and contractual plan documents for any differing requirements
- When plan/federal/state terms conflict with this policy, the plan/federal/state terms govern
Step Therapy Requirement
Step therapy requirement: For FGF23-related TIO, document history of failure, contraindication, or intolerance to vitamin D analog therapy in combination with an oral phosphate agent before approving burosumab.
- Applicable to FGF23-related tumor-induced osteomalacia (TIO) — prior failure/contraindication/intolerance to vitamin D analog + oral phosphate required
Background
X-linked hypophosphatemia (XLH) is an inherited phosphate-wasting disorder driven by elevated fibroblast growth factor 23 (FGF23), resulting in renal phosphate wasting, chronic hypophosphatemia, and impaired bone mineralization. Clinically, XLH presents with rickets or osteomalacia, delayed growth, bone pain, deformities, and increased fracture risk. Burosumab is an FGF23-blocking monoclonal antibody that restores serum phosphate toward normal and is indicated for XLH in patients aged 6 months and older. Tumor-induced osteomalacia (TIO) is an acquired, typically paraneoplastic condition in which FGF23-secreting phosphaturic tumors cause similar FGF23-mediated hypophosphatemia and osteomalacia; burosumab is indicated for FGF23-related TIO in patients aged 2 years and older when the tumor cannot be curatively resected or localized.
Definitions
Policy History and Revisions
Policy retired and Louisiana plan membership disenrolled on Apr. 1, 2026.
Routine review completed with no change to coverage guidelines; previous policy version archived (CSLA2024D0071M).
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