Pegaspargase (Oncaspar) — CPB 0959 | AETNA Coverage Update

Aetna modified CPB 0959 for pegaspargase (Oncaspar), effective December 4, 2025. Here's what billing teams need to know before submitting claims under J9266.

Aetna updated its coverage policy for pegaspargase (Oncaspar) under CPB 0959. The revision addresses medical necessity criteria for two approved indications. CPB 0959 as of December 4, 2025 explicitly includes Extranodal Natural Killer/T-cell Lymphoma (ENKL) and Aggressive NK-cell Leukemia (ANKL) among covered indications, alongside Acute Lymphoblastic Leukemia (ALL) and Lymphoblastic Lymphoma (LL). The primary reimbursement code at stake is J9266 (injection, pegaspargase, per single dose vial), billed alongside chemotherapy administration codes 96413–96417 and 96401.

If your oncology billing team handles any of these diagnoses, this policy update directly affects your claim denial exposure.

Quick-Reference Table

Aetna Pegaspargase Coverage Criteria and Medical Necessity Requirements 2025

The Aetna pegaspargase coverage policy under CPB 0959 recognizes two clinical scenarios as medically necessary. Both require pegaspargase to be used in conjunction with multi-agent chemotherapy. That conjunction requirement is not optional — it is the core of the medical necessity determination.

Indication 1: Acute Lymphoblastic Leukemia (ALL) and Lymphoblastic Lymphoma (LL). Aetna covers pegaspargase for ALL and LL when used as part of a multi-agent chemotherapy regimen. The relevant diagnosis codes are C91.0, C91.1, and C91.2 for ALL, and C83.51 through C83.59 for Lymphoblastic (diffuse) lymphoma.

Indication 2: ENKL and ANKL. CPB 0959 as of December 4, 2025 explicitly includes pegaspargase coverage for Extranodal Natural Killer/T-cell Lymphoma (ENKL) and Aggressive NK-cell Leukemia (ANKL) when used with multi-agent chemotherapy. The ICD-10 codes for ENKL are C86.0 and C86.1. ANKL maps to C94.80, C94.81, and C94.82.

ENKL and ANKL are rare, aggressive malignancies. The explicit inclusion of these diagnoses in CPB 0959 clarifies how you should structure your clinical documentation for medical necessity.

For continuation of therapy, Aetna requires no evidence of unacceptable toxicity or disease progression. Document this actively in the medical record. It directly supports your reauthorization requests. A vague chart note will not carry a renewal through.

This policy covers commercial plans only. Medicare patients require a separate review under Aetna's Medicare Part B criteria. Do not apply these commercial billing guidelines to Medicare claims.

Aetna Pegaspargase Exclusions and Non-Covered Indications

Aetna is direct on this point: all other indications for pegaspargase are considered experimental, investigational, or unproven. There is no ambiguity in the language. If the diagnosis does not fall under ALL, LL, ENKL, or ANKL, you will not get coverage under this policy.

This matters because pegaspargase has been studied in other contexts — including some T-cell lymphomas and relapsed settings not specifically named here. If your oncologist is using Oncaspar off-label for any indication outside the four covered diagnoses, expect a claim denial.

If you have patients currently receiving pegaspargase for indications outside these four categories, talk to your compliance officer before December 4, 2025. This is not a situation to manage retroactively.

The hepatic failure ICD-10 codes included in the policy (K72.0, K72.1, K72.10, K72.11, K72.90, K72.91) appear as monitoring-related codes — hepatotoxicity is a known pegaspargase risk. These are not coverage indications. They are clinically relevant to the safety monitoring framework and may appear on claims documenting adverse events, but they do not trigger standalone coverage.

Coverage Indications at a Glance

Aetna Pegaspargase Billing Guidelines and Action Items 2025

Here's what your billing and revenue cycle team needs to do before and after December 4, 2025.

1. Review active claims for ENKL and ANKL patients before December 4, 2025.
If you have patients with ENKL (C86.0, C86.1) or ANKL (C94.80–C94.82) currently receiving pegaspargase, confirm that your clinical documentation aligns with the coverage criteria in the updated CPB 0959. Check with your compliance officer or billing consultant about how your specific Aetna plan handles coverage changes for active patients. Note: the source policy does not specify prior authorization requirements — those vary by plan and are not addressed in CPB 0959. Contact Aetna directly to confirm authorization processes for your plan.

2. Update your charge capture to link J9266 to covered diagnosis codes.
Your billing system should flag any J9266 claim that does not pair with C91.x, C83.5x, C86.0, C86.1, or C94.8x. Claims submitted with ICD-10 codes outside these groups will land as experimental/investigational denials. Fix the charge capture logic before the effective date.

3. Confirm multi-agent chemotherapy documentation for every claim.
The coverage criteria require pegaspargase to be used "in conjunction with multi-agent chemotherapy." This is not implied by the diagnosis alone. Your clinical documentation must show that pegaspargase is part of a multi-agent regimen. If the chart does not explicitly document this, your medical necessity argument falls apart on appeal.

4. Bill chemotherapy administration codes correctly alongside J9266.
Pegaspargase billing requires the appropriate administration code paired with the drug code. For intravenous administration, use 96413, 96414, 96415, 96416, or 96417 depending on the route and technique. For subcutaneous or intramuscular routes, use 96401. Note: CPB 0959 does not specify a billing sequence for these codes. The appropriate code selection depends on the administration method and your standard CPT coding guidelines — not this policy. Consult your coding resources or coding consultant for sequencing guidance. Do not bill administration codes without the corresponding J9266 drug code — and vice versa.

5. Separate the hepatic failure codes from the coverage determination.
K72.0, K72.1, K72.10, K72.11, K72.90, and K72.91 appear in the CPB 0959 code list, but these are not coverage-triggering diagnoses. Use them as secondary codes when documenting adverse events or monitoring complications — not as primary diagnoses to support Oncaspar reimbursement. A claim submitted with a hepatic failure code as the primary diagnosis for pegaspargase will be denied.

6. Manage continuation requests with documented clinical status.
Reauthorization for ongoing pegaspargase therapy requires active evidence of no disease progression and no unacceptable toxicity. Build a documentation checklist for your oncology nurses and providers. The note needs to say these things explicitly — not just "patient tolerating treatment well." Vague language does not pass Aetna's utilization management review.

7. Apply these billing guidelines to commercial plans only.
If your practice sees both commercial Aetna members and Aetna Medicare Advantage patients, do not apply CPB 0959 criteria to Medicare claims. Medicare Part B has a separate pathway. Mixing them up is a fast route to a denied claim and a complicated appeal.

CPT, HCPCS, and ICD-10 Codes for Pegaspargase Under CPB 0959

Covered HCPCS Code (When Selection Criteria Are Met)

Related HCPCS Code (Not a Coverage Trigger Under This Policy)

Chemotherapy Administration CPT Codes

Note: The source policy lists 96413, 96414, 96415, 96416, and 96417 only as "Chemotherapy administration, intravenous infusion technique." Sub-descriptions are not specified in CPB 0959. Use your standard CPT coding resources to determine the correct code for the specific administration technique.

Key ICD-10-CM Diagnosis Codes