Ilaris (canakinumab) — HCPCS J0638

About Ilaris (canakinumab) FDA label verified May 2026

Ilaris (canakinumab) is a fully human IgG1κ monoclonal antibody manufactured by Novartis Pharmaceuticals Corporation that binds and neutralizes interleukin-1 beta (IL-1β) — the upstream cytokine driver of the inflammasome-mediated autoinflammatory disease family. It is supplied as a 150 mg single-dose vial in two presentations: the original lyophilized powder (NDC 0078-0582-61) reconstituted with 1 mL sterile water for injection to yield 150 mg/mL, and a newer ready-to-use 150 mg/mL solution for injection (NDC 0078-0734-61). Both presentations bill identically under HCPCS J0638 at 1 mg per unit.

Ilaris carries six FDA-approved indications across the autoinflammatory disease spectrum: Cryopyrin-Associated Periodic Syndromes (CAPS) — the original 2009 approval covering Familial Cold Autoinflammatory Syndrome (FCAS), Muckle-Wells Syndrome (MWS), and Neonatal-Onset Multisystem Inflammatory Disease (NOMID, also called CINCA); Systemic Juvenile Idiopathic Arthritis (SJIA) in patients aged 2 and older (May 2013); the three hereditary periodic fever syndromes TRAPS, HIDS/MKD, and FMF (all September 2016); and most recently Adult-Onset Still's Disease (AOSD) — for which Ilaris is the first FDA-approved therapy, granted June 16, 2020. The autoinflammatory diseases share an IL-1β-driven pathobiology, which is why a single monoclonal antibody can address all of them, though dosing regimens and required diagnostic confirmation differ.

For billers, J0638 is operationally straightforward (1 mg = 1 unit, SC route, CPT 96372 per administration) but PA-heavy. Each indication has distinct PA requirements: hereditary periodic fevers gate on documented genetic mutations (NLRP3, MEFV, MVK, TNFRSF1A), SJIA gates on prior NSAID and corticosteroid trials, and AOSD requires documented Yamaguchi or Fautrel criteria. Canakinumab has rare-disease pricing — ASP per mg approaches $150 in Q2 2026 — and there are no biosimilars or therapeutic equivalents under J0638. The page below walks the full code, modifier, and payer pattern for each indication.

Two formulations — lyophilized vs ready-to-use solution FDA NDC Directory May 2026

Both bill under J0638. The difference is whether you reconstitute or draw straight from the vial.

Dosing by indication FDA label verified May 2026

All routes are SC. The mg-per-dose varies by indication and patient weight band.

Master dosing matrix

Worked example 1 — adult CAPS (75 kg, 150 mg q8wk)

Worked example 2 — pediatric SJIA (25 kg, 4 mg/kg q4wk)

Worked example 3 — adult FMF (150 mg q4wk, titrated to 300 mg)

Indications differ in the interval (q4wk vs q8wk) and in whether the dose is flat or weight-based. SJIA and AOSD share the same regimen (4 mg/kg q4wk, max 300 mg) — they are clinically the same disease spanning pediatric and adult populations. Pediatric mg/kg dosing in any indication is the only situation that routinely generates partial-vial waste; adult flat doses at 150 or 300 mg consume whole vials with no waste.

NDC reference FDA NDC Directory verified May 2026

Administration codes CPT verified May 2026

Ilaris is subcutaneous only. There is no IV formulation, so infusion admin codes do not apply.

Modifiers CMS verified May 2026

JW — required for pediatric mg/kg waste

JW reports the discarded portion of a single-dose vial. Ilaris is supplied in 150 mg single-dose vials, and pediatric mg/kg dosing in any of the six indications routinely calls for a partial-vial dose. The most common scenario is SJIA / AOSD at 4 mg/kg, where any patient under ~37.5 kg consumes less than a full 150 mg vial. Bill the administered units on the primary line and the wasted units on a separate line with the JW modifier. Both administered and discarded units pay at ASP + 6%.

JZ — required when there is no waste

JZ applies when a full 150 mg vial is administered with zero discard. This is the typical adult scenario for CAPS (150 mg q8wk), TRAPS, HIDS/MKD, and FMF (150 mg q4wk). Also applies when SJIA/AOSD dosing for a 37.5+ kg patient yields exactly 150 mg, or when the titrated 300 mg dose is split across exactly two whole vials. Per CMS's July 2023 single-dose container policy, one of JZ or JW must be on every J0638 claim.

Modifier 25 — same-day E/M

Use modifier 25 on the E/M code when a significant, separately identifiable evaluation and management service is performed on the same day as the injection. Routine pre-injection clinical assessment is bundled into 96372.

340B modifiers (JG, TB)

For 340B-acquired Ilaris (typical at academic pediatric rheumatology programs), follow your MAC's current 340B modifier policy. Hospital outpatient departments billing under OPPS are subject to specific 340B reporting requirements; office-based 340B reporting varies by MAC.

ICD-10-CM by indication FY2026 verified May 2026

Six FDA-approved indications, six diagnostic code families. Pair with genetic-test documentation for the hereditary periodic fevers.

Site of care & place of service Verified May 2026

Ilaris is administered subcutaneously and the injection itself takes seconds. The pre- and post-injection observation burden is minimal compared to IV biologics, which means the rheumatology office (POS 11) is by far the most common site of care. Pediatric rheumatology clinics and specialty autoinflammatory disease programs are the second-most-common setting for SJIA, CAPS, and pediatric periodic fevers. Hospital outpatient departments see a smaller share — commercial payers run site-of-care UM steering away from HOPD for SC biologics where clinically appropriate. Home self-injection is uncommon but viable, especially with the ready-to-use solution presentation (NDC 0078-0734-61) that eliminates reconstitution training.

Claim form field mapping Novartis Patient Support 2026

From Novartis Patient Support Ilaris HCP coding & coverage materials.

Payer policy snapshot Reviewed May 2026

All major payers require PA. The PA requirements differ sharply by indication.

Step therapy

For SJIA, most payers require documented prior trial (and failure / intolerance) of NSAIDs and systemic corticosteroids; some also require prior anakinra (Kineret) trial. For AOSD, prior corticosteroid trial is the standard gate. For FMF, prior colchicine therapy (the FMF standard of care) and documented colchicine resistance or intolerance is the universal gate — canakinumab is positioned as the colchicine-resistant therapy. For CAPS, TRAPS, and HIDS/MKD, there is no widely-required prior-therapy step; the genetic test and clinical diagnosis are the gates.

ACR autoinflammatory guidance

The American College of Rheumatology and the Childhood Arthritis and Rheumatology Research Alliance (CARRA) have published clinical care recommendations supporting IL-1 blockade for SJIA and the hereditary periodic fever syndromes. Canakinumab is one of three IL-1-targeted therapies in clinical use (anakinra and rilonacept being the other two) and is the only one with FDA approvals across the full autoinflammatory disease spectrum.

Medicare reimbursement CMS Q2 2026 (live)

Quarterly ASP from CMS Part B Drug Pricing File. Refreshes automatically each quarter.

Annual reimbursement by indication (illustrative, before sequestration)

Coverage

No NCD specific to canakinumab. Coverage falls under MAC LCDs for monoclonal antibodies + the autoinflammatory disease framework. All MACs cover J0638 for FDA-approved on-label indications with appropriate ICD-10 and clinical documentation. The genetic-test requirement for hereditary periodic fevers is a payer-policy gate, not a Medicare statutory limit.

Code history

• J0638 — permanent code, "Injection, canakinumab, 1 mg"; established after the 2009 CAPS approval. No prior unclassified-J period since the code was assigned shortly after initial FDA approval.

Patient assistance — Novartis Patient Support Novartis verified May 2026

• Novartis Patient Assistance Foundation (NPAF): 1-800-277-2254 / patientassistancenow.com — free Ilaris for uninsured / underinsured patients meeting income criteria. Administered by the Novartis Patient Assistance Foundation, Inc., a 501(c)(3).
• Ilaris Companion Program / Novartis Patient Support: benefits investigation, prior authorization assistance, appeal support, nurse-led patient education on storage / preparation / injection technique. Bridge product available while coverage is being established.
• Ilaris Co-Pay Program: commercial copay support — eligible commercially-insured patients pay a reduced copay per dose (program rules vary year to year; verify annual cap). Excludes Medicare, Medicaid, federal program patients.
• Foundations (Medicare patients): NORD (National Organization for Rare Disorders), HealthWell Foundation, Patient Advocate Foundation Co-Pay Relief, Patient Access Network (PAN) Foundation — verify open autoinflammatory / juvenile arthritis / rare disease funds quarterly.
• Disease-specific organizations: Autoinflammatory Alliance, Systemic JIA Foundation, FMF & AID Global Association, Arthritis Foundation — advocacy, peer support, sometimes ad hoc financial aid.
• Web: ilaris.com · patientassistancenow.com

Common denials & how to fix them

Frequently asked questions

Which indications does Ilaris (J0638) cover?

Ilaris (canakinumab) is FDA-approved for six autoinflammatory conditions: Cryopyrin-Associated Periodic Syndromes (CAPS — FCAS, MWS, NOMID/CINCA), approved 2009; Systemic Juvenile Idiopathic Arthritis (SJIA), May 2013; the periodic fever syndromes TRAPS, HIDS/MKD, and FMF, September 2016; and Adult-Onset Still's Disease (AOSD), June 16, 2020. All six share the single HCPCS J0638, but each has its own dosing regimen and ICD-10 code.

Is genetic testing required before starting Ilaris for periodic fevers?

Most commercial payers require documented genetic confirmation for the hereditary periodic fever syndromes: NLRP3 (CIAS1) mutation for CAPS, MEFV for FMF, MVK for HIDS/MKD, and TNFRSF1A for TRAPS. Submit the molecular pathology report (date, gene, variant, interpretation) with the prior authorization. SJIA and AOSD are clinical diagnoses — SJIA uses ILAR criteria, AOSD uses Yamaguchi or Fautrel criteria — and do not require a genetic test, but chart notes must demonstrate the diagnostic criteria.

How is SJIA dosing different from AOSD dosing?

Mechanistically the two are the same disease across an age continuum and the dosing is identical: 4 mg/kg subcutaneously every 4 weeks, capped at 300 mg per dose, for patients weighing at least 7.5 kg. The clinical distinction is purely age (pediatric SJIA vs adult-onset Still's). Bill the same J0638, but use M08.20 for SJIA and M06.1 for AOSD. AOSD was the most recent indication added (FDA approval June 16, 2020) and was supported by extrapolation from SJIA data plus a 36-patient AOSD trial.

How do I calculate pediatric mg/kg doses?

For SJIA / AOSD: weight (kg) × 4 mg/kg, capped at 300 mg. For TRAPS / HIDS / FMF pediatric (7.5 to ≤40 kg): weight × 2 mg/kg starting (may titrate to 4 mg/kg). For CAPS pediatric (15 to 40 kg): weight × 2 mg/kg starting (may titrate to 3 mg/kg). Worked example — a 25 kg SJIA child: 25 × 4 = 100 mg, drawn from one 150 mg single-dose vial, leaving 50 mg discarded. Bill J0638 × 100 units administered, plus J0638 × 50 units JW on a separate line for the waste.

How is reconstitution billed?

Reconstitution itself is not separately billable. The lyophilized 150 mg vial (NDC 0078-0582-61) is reconstituted with 1 mL sterile water for injection to yield 150 mg/mL, then the calculated dose volume is drawn into a syringe and administered subcutaneously. Bill J0638 for the actual mg administered, CPT 96372 for the SC injection, and apply JW for any discarded drug. The newer 150 mg/mL ready-to-use solution (NDC 0078-0734-61) skips reconstitution but bills identically.

Why is Ilaris so expensive per dose?

For Q2 2026, the Medicare Part B payment limit for J0638 is $149.574 per mg (ASP + 6%). A standard 150 mg adult dose reimburses at approximately $22,436.10 before sequestration. Canakinumab is a fully human IgG1 anti-IL-1β monoclonal antibody with rare-disease pricing and a small commercial market (CAPS prevalence is roughly 1 in 1,000,000). There are no biosimilars as of Q2 2026 and no therapeutic equivalents under J0638. Adult FMF on q4wk dosing exceeds $290,000 per year before sequestration.

What administration CPT do I use for Ilaris?

CPT 96372 — "Therapeutic, prophylactic, or diagnostic injection (specify substance or drug); subcutaneous or intramuscular." Ilaris is a subcutaneous-only product (no IV formulation) and 96372 applies to every administration. Do NOT use 96365 (therapeutic IV infusion) or 96401 (chemotherapy SC/IM) — canakinumab is non-chemotherapy and not infused. 96372 is bundled into many E/M codes when the injection is incident-to in office, but it should still be reported separately when billable per payer policy.

Is JW or JZ required on the J0638 claim?

Yes — per CMS's July 2023 single-dose container policy, one of JZ or JW must be on every J0638 claim. Use JZ when a full 150 mg vial is administered with zero waste (typical adult CAPS, TRAPS, HIDS, and FMF dosing at 150 mg flat). Use JW for any discarded portion — routine in pediatric mg/kg dosing (e.g., the 100 mg dose for a 25 kg SJIA child leaves 50 mg discarded from the 150 mg vial). The discarded portion is reimbursable when billed on a separate JW line.

Source documents

1. FDA — ILARIS (canakinumab) prescribing information (BLA 125319)
   FDA-approved label; all six indications, dosing, W&P, NDC, reconstitution
2. DailyMed — ILARIS (canakinumab injection)
   Current FDA label, NDC, package insert (both lyophilized and solution presentations)
3. Novartis — ILARIS Highlights of Prescribing Information (US)
   Manufacturer prescribing information, dosing matrix by indication and weight band
4. Ilaris HCP / Patient Support — Novartis Patient Support
   Manufacturer billing guide, claim form mapping, copay assistance program, dosing tools
5. CMS — Medicare Part B Drug ASP Pricing File
   Q2 2026 quarterly file, effective April 1 – June 30, 2026
6. SEER CanMED — HCPCS J0638 reference
7. Aetna CPB 0881 — Canakinumab (Ilaris)
   Indication-specific PA criteria, step therapy, genetic test requirements
8. Novartis press release — ILARIS FDA approval for AOSD (June 16, 2020)
   Most recent indication addition; first FDA-approved AOSD therapy
9. CLUSTER trial (NEJM 2018) — canakinumab in colchicine-resistant FMF, TRAPS, HIDS/MKD
   Pivotal trial supporting the 2016 periodic fever syndrome approvals
10. ACR clinical practice guidelines — juvenile idiopathic arthritis & autoinflammatory diseases
    Society guidance supporting IL-1 blockade as standard of care
11. CMS HCPCS Level II Quarterly Updates
12. FDA National Drug Code Directory
13. CMS — JW/JZ modifier policy (CR 12056, eff. July 2023)

About this page

We maintain this page as a living reference. Medicare ASP pricing is bound to our underlying CareCost data layer and refreshes automatically when CMS publishes new quarterly files. Coding and policy content is reviewed at least quarterly and updated whenever a source document changes.

Found an error? Email hello@carecostestimate.com.

Refresh cadence

Reviewer

Change log

• May 22, 2026 — Initial publication. ASP data: Q2 2026. Manufacturer source: Novartis Patient Support 2026. Six FDA-approved indications (CAPS, SJIA, AOSD, TRAPS, HIDS/MKD, FMF) covered. Two formulations (lyophilized + ready-to-use solution) documented.

Methodology

Every claim on this page is sourced inline. Pricing reflects the current CMS Part B Drug ASP Pricing File. Payer policies are read directly from each payer's published medical/pharmacy policy documents. Indication list and dosing are verified against the current FDA label revision. We do not paraphrase from billing-software vendor blogs.