Burosumab-twza (Crysvita) — CPB 0932 | AETNA Coverage Update

TL;DR: Aetna, a CVS Health company, modified CPB 0932 covering burosumab-twza (Crysvita), effective January 15, 2026. Here's what billing teams need to know before submitting claims.

Aetna updated its burosumab-twza coverage policy under CPB 0932 Aetna system, tightening the medical necessity criteria for two covered indications: X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO). The primary billing code is HCPCS J0584 (injection, burosumab-twza 1 mg), and every claim requires precertification. If your team bills J0584 for Crysvita without a clean prior authorization on file, expect a claim denial.

---

Field	Detail
Payer	Aetna
Policy	Burosumab-twza (Crysvita) — CPB 0932
Policy Code	CPB 0932
Change Type	Modified
Effective Date	January 15, 2026
Impact Level	High
Specialties Affected	Endocrinology, Nephrology, Metabolic Bone Disease
Key Action	Verify PHEX gene testing results and lab values are documented before submitting precertification for J0584

---

Aetna Burosumab-twza (Crysvita) Coverage Criteria and Medical Necessity Requirements 2026

The Aetna Crysvita coverage policy under CPB 0932 covers burosumab-twza for two specific indications only. Everything else is experimental. The criteria are strict, and missing even one element will trigger a denial.

Prescriber requirement: Burosumab-twza must be prescribed by — or in consultation with — an endocrinologist, nephrologist, or a physician specializing in metabolic bone disorders. A primary care prescription alone won't pass precertification. Make sure the ordering provider's specialty is documented on every prior authorization request.

X-linked Hypophosphatemia (XLH)

To meet medical necessity for XLH, the member must satisfy all three of the following conditions:

First, the member must meet at least one genetic or lab criterion:

#	Covered Indication Copy
1	Genetic testing confirming a pathogenic variant in the PHEX gene in the member, or
2	Genetic testing confirming a pathogenic PHEX variant in a directly related family member with appropriate X-linked inheritance, or
3	FGF23 level above the upper limit of normal or abnormal for the assay

Second, the member's baseline fasting serum phosphorus (CPT 84100) must be below the normal range for age.

Third, the member must have radiographic evidence of rickets or other bone disease attributed to XLH.

All three conditions are required. If you have genetic confirmation via CPT 81406 (molecular pathology, Level 7) but no radiographic evidence on file, you don't have a clean claim. Get the imaging documentation before you submit.

Tumor-Induced Osteomalacia (TIO)

TIO criteria are even more layered. The diagnosis must be confirmed by all three lab findings simultaneously:

#	Covered Indication Copy
1	FGF23 above the upper limit of normal or abnormal for the assay
2	Baseline fasting serum phosphorus (CPT 84100) below normal range for age
3	TmP/GFR (ratio of renal tubular maximum reabsorption rate of phosphate to glomerular filtration rate) below normal range for age

Beyond those labs, the member must have clinical signs or symptoms of TIO — bone pain, fractures, muscle weakness, limb deformity, craniofacial anomaly, or a localized mass. Document these in the chart explicitly.

The final TIO criterion is the one that trips up the most claims: the disease must be associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized. If the tumor has been identified and is surgically resectable, burosumab-twza is not covered. Your clinical team needs to document why resection or localization isn't feasible.

Prior Authorization and Site of Care

Precertification is required on every claim. Call (866) 752-7021 or fax (888) 267-3277. Aetna also applies its Site of Care Utilization Management Policy to burosumab-twza. That means the site where the subcutaneous injection (CPT 96372) is administered may affect reimbursement. Office-based infusion is typically preferred over hospital outpatient for specialty drug administration. Confirm the approved site of care during the prior authorization process — don't assume your current setting is approved.

Continuation of Therapy

Reauthorization is available for members currently receiving burosumab-twza who show benefit from therapy. Aetna defines benefit as disease improvement or stability — specifically: increased or normalized serum phosphate, improved bone and joint pain, fewer fractures, or improved skeletal deformities. Document these outcomes explicitly at each reauthorization. "Patient tolerating therapy" isn't enough.

---

Aetna Burosumab-twza Exclusions and Non-Covered Indications

Aetna's position is direct: all indications other than XLH and TIO are experimental, investigational, or unproven. That's a broad exclusion with real financial exposure.

Conditions like fibrous dysplasia (ICD-10 M85.0–M85.9) and tyrosinemia (E70.21) appear in the policy's code set, but they're listed as related codes — not covered indications. Billing J0584 for these diagnoses will result in a claim denial. If your practice treats patients with these conditions and a provider is exploring off-label burosumab-twza use, talk to your compliance officer before submitting any claims.

The policy does not provide a grandfather clause for members who were previously approved under older criteria. Every reauthorization is evaluated against current criteria.

---

Coverage Indications at a Glance

---

Aetna Burosumab-twza Billing Guidelines and Action Items 2026

These are the steps your billing team should take before January 15, 2026.

Copy Action Items

---

CPT, HCPCS, and ICD-10 Codes for Burosumab-twza (Crysvita) Under CPB 0932

Primary Covered HCPCS Code

Code	Type	Description Copy
J0584	HCPCS	Injection, burosumab-twza 1 mg

Key ICD-10-CM Diagnosis Codes

A note on the fibrous dysplasia codes: M85.0 through M85.9 appear in the policy's code set, but Aetna does not cover burosumab-twza for fibrous dysplasia. These codes are listed as related codes only. Do not use them as primary diagnosis codes on J0584 claims.

---