HCPCS
J2323
1 mg = 1 unit
Phase 1
Identify what you're billing
Confirm the right code, dose, and REMS program before building the claim.
Tysabri vs. Tyruko — J2323 vs. Q5134 FDA verified May 2026
Same molecule, same dose, same indications — different HCPCS, different NDC, different REMS.
Tysabri is the originator natalizumab product, FDA-approved in November 2004 and marketed by Biogen. Tyruko (natalizumab-sztn, Sandoz) is the first FDA-approved biosimilar, approved August 24, 2023. The molecule, dose, and indications are identical — but the billing code, NDC, and REMS program are separate. A site that administers both products must enroll in both REMS independently and submit claims under the correct HCPCS per dose.
| Tysabri (reference) | Tyruko (biosimilar) | |
|---|---|---|
| HCPCS | J2323 | Q5134 |
| Generic | natalizumab | natalizumab-sztn |
| NDC (300 mg vial) | 59075-0730-15 | 61314-0543-94 |
| Manufacturer | Biogen Inc. | Sandoz (Novartis) |
| FDA approval | November 23, 2004 (BLA 125104) | August 24, 2023 (BLA 761322) |
| Vial | 300 mg / 15 mL SDV | 300 mg / 15 mL SDV (identical) |
| Dose | 300 mg IV q4wk | 300 mg IV q4wk (identical) |
| Indications | RRMS + Crohn's | RRMS + Crohn's (identical) |
| REMS program | TOUCH (Biogen, 800-456-2255) | TYRUKO REMS (Sandoz, 800-489-7856) |
| Q2 2026 ASP+6% | $24.321/mg | $24.321/mg (currently identical) |
Pricing parity (for now): as of Q2 2026, CMS reports identical ASP+6% rates for Tysabri
($24.321/mg) and Tyruko ($24.321/mg). This is unusual for a biosimilar launch — expect Tyruko's per-mg
rate to drift below Tysabri's as biosimilar uptake matures. As that gap opens, payer steering toward Tyruko
will accelerate, particularly at re-authorization.
Different REMS, mandatory enrollment: a clinician with TOUCH certification cannot prescribe
Tyruko without separate TYRUKO REMS enrollment, and a clinician with TYRUKO REMS certification cannot
prescribe Tysabri without TOUCH. Same for the infusion site and the patient. Confirm the right REMS for the
product being administered.
Dosing & unit math FDA label current
From FDA prescribing information (BLA 125104).
FDA-labeled dose schedule (verbatim):
"300 mg infused intravenously over one hour, every four weeks."
- Frequency: every 4 weeks (q4wk), no loading
- Per dose: 1 vial (300 mg / 15 mL) diluted in 100 mL 0.9% NaCl
- Infusion rate: ~1 hour total infusion time
- Post-infusion observation: 1 hour for hypersensitivity surveillance per label
- 1 mg = 1 unit: bill 300 units of J2323 per dose
- No premedication routinely required (different from anti-CD20 MS DMTs)
Worked example — first-year billing
# Every 4 weeks — 300 mg infusion (1 hour)
Drug units billed: 300
HCPCS: J2323 · Modifier: JZ (whole-vial use) · Vials: 1 × 300 mg
Admin: 96365 (1 hour, therapeutic IV)
# Year-1 dose count: 13 doses (q4wk for 52 weeks)
# Total year-1 drug units billed: 3,900 (13 × 300)
Drug units billed: 300
HCPCS: J2323 · Modifier: JZ (whole-vial use) · Vials: 1 × 300 mg
Admin: 96365 (1 hour, therapeutic IV)
# Year-1 dose count: 13 doses (q4wk for 52 weeks)
# Total year-1 drug units billed: 3,900 (13 × 300)
Required pre-infusion checks (per TOUCH program)
- PML symptom screening (cognitive, motor, visual changes)
- Confirm patient is enrolled in TOUCH and current on monitoring
- Anti-JCV antibody status documented (drives PML risk stratification)
- For long-term users (>2 yr) and JCV-positive patients: heightened MRI vigilance
- No active infection
NDC reference FDA NDC Directory verified May 2026
| NDC (10-digit) | NDC (11-digit, claim form) | Package | Manufacturer |
|---|---|---|---|
59075-730-15 |
59075-0730-15 |
300 mg natalizumab in 15 mL (20 mg/mL), single-dose vial — 1 vial per carton | Biogen Inc. |
11-digit NDC required on most claim forms. Pad the middle segment with a leading zero:
59075-0730-15. Use the
N4 qualifier in CMS-1500 Box 24A and UB-04 Box 43.
Some older Tysabri references list NDC 59075-730-15 in 10-digit form — same product.
TOUCH Prescribing Program — mandatory enrollment Biogen verified May 2026
Tysabri is available only through the TOUCH Prescribing Program — a Biogen program separate from Tyruko's TYRUKO REMS.
Per FDA, "TYSABRI is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the TOUCH Prescribing Program." TOUCH (TYSABRI Outreach: Unified Commitment to Health) is operated by Biogen and is the original natalizumab REMS. Tyruko's REMS is operated by Sandoz; the two programs do not interoperate.
Who must enroll
- Prescribers: certified through TOUCH; must agree to monitoring and reporting obligations
- Pharmacies: only TOUCH-certified specialty pharmacies/distributors may dispense Tysabri
- Infusion centers: must complete TOUCH site enrollment before administering
- Patients: enrolled with prescriber, sign Patient Enrollment Form, receive Medication Guide
Required monitoring
- Baseline MRI within ~3 months prior to first dose
- Anti-JCV antibody testing at baseline + every 6 months
- Clinical follow-up: 3 months, 6 months, then every 6 months while on therapy
- Reauthorization: prescriber must determine every 6 months whether the patient should continue and submit the TYSABRI Patient Status Report and Reauthorization Questionnaire
- Post-discontinuation surveillance for at least 6 months after last dose
- Report PML cases, opportunistic-infection hospitalizations, and deaths to Biogen at 1-800-456-2255
Billing implications
There is no separate REMS HCPCS code — REMS enrollment is not billable. However, documentation of TOUCH enrollment is a frequent payer audit target. Notes should reference TOUCH enrollment identifiers on each infusion encounter. Most payers' Tysabri PA criteria require attestation that the patient is enrolled in TOUCH and current on monitoring.
Contact: TOUCH Prescribing Program / Biogen Medical Information, 800-456-2255. Web: touchprogram.com · tysabrihcp.com.
Common error: Site administers Tysabri based on existing TYRUKO REMS certification (or vice
versa). The two programs are independent — using the wrong certification is a hard REMS violation that
triggers audit and potential payer recoupment. Confirm separate TOUCH enrollment for the prescriber, site, and
patient before any Tysabri dose.
Phase 2
Code the claim
Build the line items: admin code, modifiers, ICD-10, site of care.
Administration codes CPT verified May 2026
Tysabri is non-chemotherapeutic — use therapeutic infusion codes, not chemo.
| Code | Description | When to use |
|---|---|---|
96365 |
IV infusion, for therapy/prophylaxis/diagnosis; initial, up to 1 hour | Primary code. Tysabri infuses over ~1 hour. |
96366 |
IV infusion, for therapy/prophylaxis/diagnosis; each additional hour | Typically NOT billed — infusion fits within the first hour. Post-infusion observation is not separately billable. |
96413 / 96415 |
Chemotherapy IV administration codes | Not appropriate. Natalizumab is non-chemotherapeutic. |
S9329 + 99601 / 99602 |
Home infusion HCPCS + administration CPT | Home infusion supported via TOUCH-certified home-infusion vendor; verify payer coverage. |
Why not chemo: some payers historically denied 96413 for non-chemotherapeutic monoclonal
antibodies. Tysabri (and the Tyruko biosimilar) have always billed under 96365. Don't be tempted to bill chemo
admin codes for the higher reimbursement — the documentation won't support it.
Modifiers CMS verified May 2026 — verify JZ list
JZ — whole-vial use, default expectation
Effective July 1, 2023, CMS requires JZ on all claims for single-dose container drugs when no drug is discarded — but only for codes on the CMS single-dose container list. Tysabri's 300 mg dose uses one full single-dose vial with no discard, so JZ is the expected modifier when J2323 appears on that list. Verify against the current CMS single-dose container list at billing time; the list is updated periodically and natalizumab products' inclusion has been inconsistent.
JW — rarely applies
The 300 mg dose uses one full vial; no drug is discarded in routine use. JW applies only when documented wastage occurs (very rare for natalizumab).
Same JZ/JW caveat as Tyruko: Per BuyAndBill's interpretation of CMS single-dose container
guidance, natalizumab products' inclusion on the CMS list has been inconsistent. Default behavior: include JZ
when no drug is wasted; be prepared for some MACs to either ignore the modifier or pay without it.
Modifier 25 — situational
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 infusion. Routine pre-infusion REMS check is bundled.
340B modifiers (JG, TB)
For 340B-acquired Tysabri, follow your MAC's current 340B modifier policy.
ICD-10-CM diagnosis codes FY2026 verified May 2026
Tysabri's full diagnosis space — MS family AND Crohn's family.
Multiple sclerosis
| ICD-10 | Description | Tysabri-eligible? |
|---|---|---|
G35 | Multiple sclerosis (parent) | Many payers reject parent — use specific G35.x |
G35.A | Relapsing-remitting MS | Yes (primary indication) |
G35.C0 | Secondary progressive MS, unspecified | Use if active relapses present |
G35.C1 | Active SPMS | Yes (covered indication) |
G35.D | MS, unspecified | Acceptable |
G35.B0–B2 | Primary progressive MS family | NO — not approved for PPMS |
G37.9 | CNS demyelinating, NOS | Acceptable for CIS |
Crohn's disease
| ICD-10 | Description | Tysabri-eligible? |
|---|---|---|
K50.00 / K50.01x | Crohn's of small intestine (without/with complications) | Yes |
K50.10 / K50.11x | Crohn's of large intestine (without/with complications) | Yes |
K50.80 / K50.81x | Crohn's of both small + large intestine | Yes |
K50.90 / K50.91x | Crohn's, unspecified | Yes |
Tysabri covers BOTH MS and Crohn's — but the PA pathways differ. For Crohn's, most
payers require documented inadequate response or intolerance to TNF inhibitors (e.g., infliximab, adalimumab)
before approving natalizumab. The MS DMT step-therapy rules don't apply to the Crohn's indication, and vice
versa. Bill K50.x diagnoses for the Crohn's indication; G35.x family for MS.
Site of care & place of service Verified May 2026
Tysabri's 1-hour infusion + 1-hour observation fits ambulatory infusion settings cleanly. UHC and Aetna both run site-of-care UM programs that steer natalizumab away from hospital outpatient toward non-hospital sites and home infusion.
| Setting | POS | Claim form | Electronic |
|---|---|---|---|
| Physician office | 11 | CMS-1500 | 837P |
| Ambulatory infusion suite | 49 | CMS-1500 | 837P |
| Hospital outpatient | 19 or 22 | UB-04 / CMS-1450 | 837I |
| Patient home | 12 | CMS-1500 (with home-infusion HCPCS) | 837P |
REMS site requirement: regardless of POS, the site must be enrolled in TOUCH. Home infusion
vendors must be TOUCH-certified to administer Tysabri. Confirm vendor REMS status before scheduling a home dose.
Claim form field mapping Verified May 2026
CMS-1500 / 837P (physician office, AIC; POS 11/49).
| Information | CMS-1500 box | Notes |
|---|---|---|
| NPI | 17b | Rendering provider |
| NDC qualifier + 11-digit NDC + UoM + qty | 24A shaded area | Format: N459075073015ML15 |
| HCPCS J2323 + admin CPT 96365 | 24D | Each on its own line |
| Drug units | 24G | 300 (mg) |
| ICD-10 | 21 | G35.A / G35.C1 / G35.D / G37.9 (MS) or K50.x (Crohn's) |
| PA number | 23 | Required by UHC, Aetna, most BCBS |
| REMS reference (encouraged) | Box 19 / NTE segment | TOUCH enrollment number for audit-readiness |
Form references: NUCC (CMS-1500).
Phase 3
Get paid
Combined natalizumab policies; biosimilar steering toward Tyruko at re-authorization.
Payer policy snapshot Reviewed May 2026
Most major payers cover Tysabri + Tyruko under combined natalizumab-agents policies.
| Payer | PA? | Biosimilar steering | MS + Crohn's? | Re-auth |
|---|---|---|---|---|
| UnitedHealthcare Combined natalizumab policy |
Yes | Tysabri + Tyruko at parity; switch to Tyruko approvable when superior clinical response is attested | Both covered | 12 mo |
| Aetna CPB 0751 + 2025 Clinical Program Summary |
Yes | Tyruko listed alongside Tysabri as preferred MS alternative; both require precertification | Both covered | w/ documented response |
| Anthem / Carelon PAM-077 (combined) |
Yes | Combined policy treats both as therapeutically interchangeable; biosimilar may be preferred at re-auth | Both covered | w/ disease stability |
| BCBS FEP 5.60.013 (combined natalizumab) |
Yes | Combined policy effective Jan 2025 | Both covered | w/ documented response |
Key finding: No major commercial payer requires step therapy through other MS DMTs before
approving Tysabri for the MS indication. PA criteria focus on appropriate diagnosis (MS or Crohn's), anti-JCV
antibody testing, and TOUCH enrollment. For Crohn's, most payers require documented inadequate
response or intolerance to TNF inhibitors before approving natalizumab.
Biosimilar steering watch: as of May 2026, most payers still cover Tysabri without forcing
biosimilar substitution. Several have begun steering new starts to Tyruko, and some (notably commercial
Carelon plans) preferentially approve the biosimilar at re-authorization. Existing Tysabri patients with
stable disease are generally allowed to continue, but expect this latitude to narrow as the price gap widens.
What to document for approval
- Confirmed diagnosis (MS or moderately-to-severely active Crohn's)
- Anti-JCV antibody status (baseline + ongoing)
- TOUCH enrollment confirmation (prescriber, site, patient)
- For MS: documented relapse activity; baseline MRI
- For Crohn's: documented inadequate response or intolerance to TNF inhibitors
- No active infection, no PML history, no serious immunocompromise
Medicare reimbursement CMS Q2 2026 (live)
Quarterly ASP from CMS Part B Drug Pricing File. Refreshes automatically each quarter.
Q2 2026 payment snapshot — J2323
Effective April 1 – June 30, 2026 · Based on 4Q25 ASP submissions
ASP + 6%
$24.321
per mg / per unit
300 mg dose
$7,296.30
300 units × ASP+6%
After sequestration
~$7,150
~2% reduction (actual paid)
Annualized cost: 13 doses/year × $7,296.30 = ~$94,852/year per patient
before sequestration and copay assistance. Tysabri and Tyruko are currently at ASP parity in CMS Q2 2026
files; expect divergence in subsequent quarters as biosimilar pricing matures.
Coverage
No NCD or LCD specific to natalizumab. Coverage falls under the generic drug-coverage LCD framework (e.g., LCD L33394). All MACs cover J2323 for FDA-approved on-label indications. Bill with G35.x for MS or K50.x for Crohn's.
Code history
- 2004 — FDA approval; initially billed under unclassified codes
- J2323 — permanent code, "Injection, natalizumab, 1 mg" (1 mg = 1 unit)
Patient assistance — Biogen Above MS Biogen verified May 2026
- Biogen Support Services / Above MS: 1-800-456-2255 (M–F)
- Tysabri Co-Pay Program: commercial copay assistance for eligible patients (excludes Medicare, Medicaid, federal program patients)
- Biogen Foundation / Patient Assistance Program (PAP): free product for eligible uninsured / underinsured patients
- Bridge / replacement programs: for coverage gaps and lost / damaged product
- In-home training: coordination through TOUCH-certified home infusion vendors
- TOUCH Prescribing Program: 800-456-2255 (REMS support — same number as patient services)
- Web: tysabri.com · tysabrihcp.com
Need to model what a specific patient will actually pay after copay assistance, deductible, coinsurance,
and OOP max? Run a CareCost Estimate — J2323 pre-loaded.
Phase 4
Fix problems
REMS confusion (TOUCH vs TYRUKO REMS), J-code mix-ups, and biosimilar substitution at re-auth are the top three.
Common denials & how to fix them
| Denial reason | Common cause | Fix |
|---|---|---|
| REMS not on file | Site administered Tysabri based on TYRUKO REMS certification (or vice versa) | Enroll in TOUCH independently. Re-submit with TOUCH enrollment number documented. Be prepared for REMS audit + recoupment risk. |
| Wrong J-code (Q5134 instead of J2323) | Tysabri billed under Tyruko biosimilar code | Resubmit under J2323. Confirm vial NDC matches: 59075-0730-15 = Tysabri, 61314-0543-94 = Tyruko. |
| Biosimilar substitution required at re-auth | Payer policy now prefers Tyruko for new starts or at re-authorization | If patient is stable on Tysabri, appeal with continuity-of-care documentation. If switching is required, transition through TYRUKO REMS enrollment. |
| Wrong admin code (96413) | Chemo admin code billed for non-chemo natalizumab | Resubmit with 96365 (therapeutic IV, 1 hour). Always 96365 for natalizumab. |
| JZ/JW modifier dispute | MAC interpretation of single-dose container list inconsistent | Verify CMS list at billing time. Default: include JZ when no waste; document if rejected. |
| Wrong ICD-10 (PPMS for MS) | G35.B0/B1/B2 used — natalizumab not approved for PPMS | If patient has PPMS, switch to Ocrevus (J2350). Use G35.A (RRMS) or G35.C1 (active SPMS) for Tysabri MS billing. |
| Crohn's PA — missing TNF failure | Crohn's PA submitted without documented TNF-inhibitor inadequate response/intolerance | Submit prior TNF treatment history (infliximab, adalimumab, certolizumab). Most payers require this for the Crohn's indication. |
| NDC format | 10-digit NDC submitted; payer requires 11-digit | Use 11-digit form: 59075-0730-15 with N4 qualifier. |
| Anti-JCV not documented | Payer requires anti-JCV antibody status for PA | Submit anti-JCV antibody result. If positive, include risk-benefit discussion documentation. |
Frequently asked questions
What is the HCPCS code for Tysabri?
Tysabri (natalizumab) is billed under HCPCS J2323 — "Injection, natalizumab, 1 mg." Each
milligram equals one billable unit, so the standard 300 mg IV dose is billed as 300 units. The biosimilar
Tyruko (natalizumab-sztn) uses a separate code, HCPCS Q5134, effective April 1, 2024.
How is Tysabri dosed?
300 mg IV infusion over approximately 1 hour, every 4 weeks. Each dose uses one full 300 mg / 15 mL single-dose vial. No loading dose. Identical to the Tyruko biosimilar.
Does the JZ or JW modifier apply to Tysabri?
JZ may apply when no drug is wasted (the 300 mg dose uses one full vial); JW rarely applies. As with Q5134, the CMS single-dose container list governs JZ/JW applicability and has been inconsistent for natalizumab products. Default behavior: include JZ when no drug is wasted, and verify against your MAC's current single-dose container guidance at billing time.
What is the administration code for Tysabri?
CPT 96365 — "Intravenous infusion, for therapy, prophylaxis, or diagnosis; initial, up to
1 hour." Natalizumab is non-chemotherapeutic, so 96413 (chemo administration) is NOT appropriate. The FDA
label specifies a 1-hour infusion, so 96366 (each additional hour) is typically not billed.
Does Tysabri share REMS with Tyruko?
No. Tysabri uses the TOUCH Prescribing Program operated by Biogen, contact 800-456-2255. The Tyruko biosimilar has its own separate REMS — TYRUKO REMS — operated by Sandoz, contact 800-489-7856. Sites administering both products must enroll in BOTH REMS independently. TOUCH certification does not authorize Tyruko, and TYRUKO REMS certification does not authorize Tysabri.
What is the boxed warning for Tysabri?
Progressive multifocal leukoencephalopathy (PML) — an opportunistic JC virus infection that usually leads to death or severe disability. Risk factors: anti-JCV antibody positivity, treatment duration over 2 years, prior immunosuppressant use. Anti-JCV antibody testing is required for risk stratification. MRI surveillance is required at baseline, 3 months, 6 months, then every 6 months on therapy and 6 months post-discontinuation.
Is Tysabri approved for both MS and Crohn's disease?
Yes. Tysabri's label covers relapsing forms of multiple sclerosis (RRMS, active SPMS, CIS) in adults AND moderately-to-severely active Crohn's disease in adults with inadequate response or intolerance to conventional therapies and TNF inhibitors. Most major commercial payers cover both indications under combined natalizumab-agents policies.
Are payers steering Tysabri patients to the Tyruko biosimilar?
Increasingly, yes. Most major payers — UnitedHealthcare, Aetna, Carelon/Anthem, BCBS FEP — now publish combined natalizumab-agents policies that treat Tysabri and Tyruko as therapeutically interchangeable. While Tysabri remains broadly covered, some payers explicitly prefer the biosimilar at re-authorization. As pricing diverges (Tyruko's discount is expected to widen over time), expect more aggressive biosimilar steering, particularly for new starts.
What is the Medicare reimbursement for J2323?
For Q2 2026, the Medicare Part B payment limit for J2323 is $24.321 per mg (ASP + 6%) — currently identical to the Tyruko biosimilar Q5134 at $24.321/mg, indicating CMS pricing parity. The standard 300 mg dose reimburses at approximately $7,296.30 before sequestration. ASP is updated quarterly by CMS.
Reference
Sources & methodology
Every claim on this page is sourced. Methodology and review history below.
Source documents
- DailyMed — TYSABRI (natalizumab) Prescribing Information
- Biogen — TYSABRI Prescribing Information PDF
- TOUCH Prescribing Program (Biogen)
- TYSABRI HCP — TOUCH Online
- TOUCH Program Overview (PDF)
- CMS — Medicare Part B Drug ASP Pricing File
- CMS — HCPCS quarterly update file (canonical J-code source)
- BuyAndBill — J2323 reference page
- AAPC — HCPCS J2323
- Aetna Clinical Policy Bulletin 0751 — Natalizumab
- UnitedHealthcare — Natalizumab (Tyruko & Tysabri) policy
- FDA National Drug Code Directory
- FDA — TYSABRI label (BLA 125104, historical)
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
| Element | Cadence | How it's refreshed |
|---|---|---|
| Medicare ASP pricing | Quarterly | Auto-bound to CareCost ASP layer; updates on CMS file release. |
| Payer policies (UHC, Aetna, Carelon, BCBS) | Semi-annual | Manual review against published payer policy documents. |
| HCPCS / CPT / modifier rules + CMS single-dose container list | Quarterly | JZ/JW applicability for J2323 specifically requires more frequent verification. |
| NDC, dosing, FDA label | Event-driven | Tied to manufacturer document version + FDA label revision date. |
| TOUCH program requirements | Annual | Reviewed against Biogen TOUCH program documentation. |
| Biosimilar substitution policy | Quarterly | Watch for payer steering toward Tyruko at re-authorization. |
Reviewer
Pending SME review. This page is staff-authored from primary sources (FDA, CMS, manufacturer,
payer documents — all linked above). Final review by our SME, Catherine Rose (CPC), is in progress.
Until that review is complete, treat this as a draft reference and verify each cited source for high-stakes
claims.
Change log
- — Initial publication. ASP data: Q2 2026 (J2323 = $24.321/mg, parity with Q5134). Payer policies: UHC combined natalizumab, Aetna CPB 0751, Carelon PAM-077, BCBS FEP 5.60.013. Reciprocal of Tyruko (Q5134) page.
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. We do not paraphrase from billing-software vendor blogs. When CMS guidance is ambiguous (as with the natalizumab single-dose container list), we surface the ambiguity rather than asserting a definitive answer.