Aetna modified CPB 0948 for emapalumab-lzsg (Gamifant), effective December 9, 2025. Here's what billing teams need to know before submitting claims.
Aetna, a CVS Health company, updated its Gamifant coverage policy under CPB 0948 to add a second covered indication: macrophage activation syndrome (MAS) in known or suspected Still's disease. The primary billing code for this drug is HCPCS J9210 (emapalumab-lzsg, 1 mg). If your team handles oncology, rheumatology, or pediatric billing, this change expands your reimbursement opportunities — but only if documentation is airtight from day one.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | Aetna, a CVS Health company |
| Policy | Emapalumab-lzsg (Gamifant) — CPB 0948 |
| Policy Code | CPB 0948 |
| Change Type | Modified |
| Effective Date | December 9, 2025 |
| Impact Level | High |
| Specialties Affected | Hematology, Rheumatology, Pediatric Subspecialties, Oncology |
| Key Action | Update prior authorization workflows and documentation checklists to include the new MAS/Still's disease indication before submitting J9210 claims |
Aetna Emapalumab-lzsg Coverage Criteria and Medical Necessity Requirements 2025
CPB 0948 now covers two distinct indications. Each has its own medical necessity ladder. Get one rung wrong and you're looking at a claim denial.
Primary HLH
Aetna considers J9210 medically necessary for primary hemophagocytic lymphohistiocytosis (HLH) when the member meets all five criteria below.
Criteria one: prior treatment failure. The member must have refractory, recurrent, or progressive disease — or documented intolerance — to conventional HLH therapy. That means etoposide (J8560, J9181), dexamethasone (J1100, J8540, J8541), cyclosporine (J7502, J7515, J7516), or antithymocyte globulin (J7504, J7511). Document which agents were tried and why they failed. Payers don't take your word for it.
Criteria two: confirmed diagnosis. Aetna requires confirmation by either a gene mutation in PRF1, UNC13D, STX11, or STXBP2 — or the presence of at least five clinical signs and symptoms of HLH per the policy appendix. ICD-10 D76.1 maps to this indication. Make sure your diagnosis coding matches what's in the genetic or clinical workup notes.
Criteria three: rule out secondary HLH. Autoimmune disease, persistent infection, malignancy, and loss of inhibitory immune mechanisms must all be evaluated and documented as ruled out. If the record doesn't show this explicitly, prior authorization reviewers will flag it.
Criteria four and five: TB screening. Every member must be evaluated for tuberculosis risk factors and screened with either the PPD skin test (CPT 86580) or an interferon gamma release assay (CPT 86480 or 86481) before starting therapy. If the member tests positive or is at high risk, prophylactic TB treatment must start before the first Gamifant infusion. This isn't optional — it's a hard stop in the coverage policy.
MAS in Still's Disease — The New Indication
This is the addition that makes the December 9, 2025, effective date matter. Aetna now covers Gamifant for MAS in known or suspected Still's disease. This maps to ICD-10 M06.1 (Adult-onset Still's disease) and M08.20–M08.2A (Juvenile rheumatoid arthritis with systemic onset — systemic JIA).
Six criteria apply here. All six must be met.
Criteria one: Confirmed or suspected systemic Juvenile Idiopathic Arthritis (sJIA) or Adult-onset Still's disease (AOSD).
Criteria two: Active MAS confirmed by clinical findings — persistent fever, elevated or rising ferritin, cytopenias, hepatic dysfunction, coagulopathy, splenomegaly, or CNS dysfunction. Document specifics, not just the diagnosis.
Criteria three: Documented inadequate response or intolerance to high-dose IV glucocorticoids. The policy specifically calls out prednisolone given as 30 mg/kg pulses over three consecutive days. If your patient received a different steroid regimen, document why and how the clinical team determined it was equivalent.
Criteria four: Primary HLH, active infections, and malignancy must all be evaluated for and ruled out. Same logic as the HLH pathway — the record needs to show this work was done.
Criteria five and six: TB screening with CPT 86580, 86480, or 86481. Same requirement as HLH — prophylactic treatment before starting Gamifant if the member screens positive or has risk factors.
The infusion itself bills under CPT 96365 (initial infusion) and CPT 96366 (each additional hour). Those codes apply regardless of which indication you're billing under.
Aetna Gamifant Exclusions and Non-Covered Indications
Aetna's language here is broad and clear. All indications outside of primary HLH and MAS in Still's disease are considered experimental, investigational, or unproven.
That's a wide exclusion. If a provider wants to use Gamifant off-label — even for a related condition — expect a denial under this coverage policy. Appeals are possible, but you'll need peer-reviewed literature and a strong medical necessity argument. Talk to your compliance officer before submitting those claims.
Coverage Indications at a Glance
| Indication | Status | Key Codes | Notes |
|---|---|---|---|
| Primary HLH — refractory, recurrent, or progressive disease | Covered | J9210, D76.1, CPT 96365/96366 | All five criteria required; prior auth expected |
| Primary HLH — intolerance to conventional therapy | Covered | J9210, D76.1, CPT 96365/96366 | Document specific agents and intolerance reason |
| MAS in sJIA or AOSD | Covered (new as of 12/9/2025) | J9210, M06.1, M08.20–M08.2A, CPT 96365/96366 | All six criteria required; TB screening mandatory |
| All other indications | Not Covered | — | Considered experimental, investigational, or unproven |
| Continuation of therapy (HLH or MAS) | Covered | J9210, CPT 96365/96366 | Requires documented positive clinical response |
Aetna Gamifant Billing Guidelines and Action Items 2025
| # | Action Item |
|---|---|
| 1 | Update your prior authorization checklist before December 9, 2025. The MAS/Still's disease indication is new. If your PA template only includes HLH criteria, you'll submit incomplete requests for the new indication and collect denials instead of authorizations. Add all six MAS criteria to your PA workflow now. |
| 2 | Attach TB screening results to every PA request. CPT 86480, 86481, and 86580 are listed in the policy for a reason. Aetna reviewers will look for evidence that TB screening happened before therapy started. If that documentation isn't in the PA submission, expect a delay or denial. |
| 3 | Confirm diagnosis coding maps to the correct ICD-10. D76.1 for primary HLH. M06.1 for AOSD. M08.20–M08.2A for sJIA. A mismatch between the ICD-10 on the claim and the approved indication will trigger a denial even if the PA was approved. Check this at charge capture. |
| 4 | Document prior therapy failure for both indications. For HLH, show that etoposide, dexamethasone, cyclosporine, or antithymocyte globulin was tried and failed. Use the corresponding HCPCS codes — J8560 or J9181 for etoposide, J1100 for dexamethasone, J7502/J7515/J7516 for cyclosporine, J7504/J7511 for antithymocyte globulin. For MAS, document the specific steroid regimen used and the response. Aetna's language calls out 30 mg/kg prednisolone pulses specifically. |
| 5 | Build a continuation-of-therapy re-authorization trigger. Continuation is covered when members achieve or maintain positive clinical response. That means you need a process to pull clinical notes showing improvement in lab or clinical parameters before the renewal date. Don't wait until authorization expires to chase this documentation. |
| 6 | If you bill for MAS/Still's disease Gamifant claims and your team isn't experienced with rheumatology prior auth, loop in your billing consultant before the first submission. The criteria are detailed, and Aetna's reviewers will apply them strictly. One missing element means a denial and a delay in patient care. |
| Previous Version | Current Version |
|---|---|
| Coverage is considered experimental and investigational for all indications | Coverage is considered medically necessary when specific criteria are met |
| Prior authorization is not required | Prior authorization is required for initial treatment |
| Documentation must include clinical history | Documentation must include clinical history |
| Re-review every 24 months | Re-review every 12 months with updated clinical documentation |
CPT, HCPCS, and ICD-10 Codes for Emapalumab-lzsg Under CPB 0948
Covered HCPCS Code (When Selection Criteria Are Met)
| Code | Type | Description |
|---|---|---|
| J9210 | HCPCS | Injection, emapalumab-lzsg, 1 mg |
Infusion Administration Codes
| Code | Type | Description |
|---|---|---|
| 96365 | CPT | Intravenous infusion, for therapy, prophylaxis, or diagnosis; initial, up to 1 hour |
| 96366 | CPT | Intravenous infusion, for therapy, prophylaxis, or diagnosis; each additional hour |
TB Screening Codes (Required Pre-Treatment)
| Code | Type | Description |
|---|---|---|
| 86480 | CPT | Tuberculosis test, cell mediated immunity antigen response measurement; gamma interferon |
| 86481 | CPT | Tuberculosis test, cell mediated immunity antigen response measurement; enumeration of gamma interferon releasing cells |
| 86580 | CPT | Skin test; tuberculosis, intradermal |
Conventional Therapy Reference Codes (Supporting Prior Treatment Failure Documentation)
| Code | Type | Description |
|---|---|---|
| J1100 | HCPCS | Injection, dexamethasone sodium phosphate, 1 mg |
| J7502 | HCPCS | Cyclosporine, oral, 100 mg |
| J7504 | HCPCS | Lymphocyte immune globulin, antithymocyte globulin, equine, parenteral, 250 mg |
| J7511 | HCPCS | Lymphocyte immune globulin, antithymocyte globulin, rabbit, parenteral, 25 mg |
| J7515 | HCPCS | Cyclosporine, oral, 25 mg |
| J7516 | HCPCS | Injection, cyclosporine, 250 mg |
| J7637 | HCPCS | Dexamethasone, inhalation solution, compounded product, administered through DME, concentrated form |
| J7638 | HCPCS | Dexamethasone, inhalation solution, compounded product, administered through DME, unit dose form |
| J8540 | HCPCS | Dexamethasone, oral, 0.25 mg |
| J8541 | HCPCS | Dexamethasone (Hemady), oral, 0.25 mg |
| J8560 | HCPCS | Etoposide, oral, 50 mg |
| J9181 | HCPCS | Injection, etoposide, 10 mg |
Key ICD-10-CM Diagnosis Codes
| Code | Description |
|---|---|
| D76.1 | Hemophagocytic lymphohistiocytosis |
| M06.1 | Adult-onset Still's disease |
| M08.20–M08.2A | Juvenile rheumatoid arthritis with systemic onset |
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