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J9358

J9358 – Injection, fam-trastuzumab deruxtecan-nxki, 1 mg · NDC Crosswalk & Billing Units

HCPCS Level II J-code · Medicare Part B drug billing
J-code ● 1 NDC crosswalked per 1 MG $32.874/unit ASP+6%

This page is curated, coded, and maintained by

Compiled from public FDA, CMS, DailyMed, NADAC, and related drug data sources. Editorial policy

📋 J9358 summary

J9358 is a HCPCS Level II J-code used to bill fam-trastuzumab deruxtecan-nxki, 1 mg, billed per 1 MG. The number of billing units to report depends on the dose administered and the NDC/package billed — use the calculator below.

Brand names associated with J9358: Enhertu

Code J9358 Billing unit 1 MG Payment limit $32.874/unit NDC-Crosswalk 1 Quarter Q3 2026 RxCUI Atlas Trace the drug concept →

⚠ An NDC↔HCPCS crosswalk and a published payment limit do not guarantee payer coverage or payment. Always verify the current payer policy and claim format before billing.

🗂️ Key billing facts

HCPCS codeJ9358
DescriptorInjection, fam-trastuzumab deruxtecan-nxki, 1 mg
Billing unit1 MG
Payment limit / unit$32.874
Est. ASP / unit$31.013 est.
Mapped NDCs1
Data periodQ3 2026
Last updated2026-08-20

💊 About Fam-trastuzumab deruxtecan-nxki Injection DRUG GUIDE

Enhertu (fam-trastuzumab deruxtecan-nxki) is used to treat adults with certain HER2-positive, HER2-low, or HER2-ultralow cancers.

It covers a wide range of situations — from early-stage breast cancer before or after surgery, to metastatic (spread) breast cancer, to lung, stomach, and other solid tumors.Specifically, Enhertu is approved for: HER2-positive early breast cancer (as neoadjuvant treatment before surgery, or as adjuvant treatment after surgery when cancer remains); unresectable or metastatic HER2-positive breast cancer (alone or with pertuzumab); metastatic HER2-low or HER2-ultralow hormone receptor-positive breast cancer; HER2-mutant non-small cell lung cancer; HER2-positive locally advanced or metastatic gastric or gastroesophageal junction cancer; and HER2-positive (IHC 3+) unresectable or metastatic solid tumors with no satisfactory alternatives.

Some of these uses are approved under accelerated approval and may require further confirmation of benefit.

Read the full Fam-trastuzumab deruxtecan-nxki Injection drug guide →
Clinical overview from our editorial drug guide for Fam-trastuzumab deruxtecan-nxki Injection. For billing reference, see the sections above.

🧾 Billing & reimbursement HCPCS · CMS · EFF. Q3 2026

📅 Payment limits effective Q3 2026 — from the CMS Medicare Part B Payment Limit File (revised quarterly).
Medicare payment limit / unit
$32.874
Est. ASP / unit
$31.013 est.
Est. after 2% sequester
$32.217
HCPCS dosage
1 MG
The CMS payment limit is the Medicare Part B drug allowance (ASP + 6%, statutory). After the 2% federal sequester the effective payment is ≈ ASP + 4.3%; estimated ASP = payment limit ÷ 1.06. Source: CMS Medicare Part B Payment Limit File (quarterly), Q3 2026.
Full HCPCS code details (official CMS record)
Long descriptionInjection, fam-trastuzumab deruxtecan-nxki, 1 mg
CoverageC — Carrier/MAC judgment
Pricing indicator51 — Drug — priced under the ASP methodology
Type of service1 — Medical care
BETOS-2O1E
ASC payment groupYY
Action codeN — No maintenance this year
Effective date2020-07-01
Date added2020-07-01
Source: CMS HCPCS Level II code file (imported via admin).

🧮 Dosing & billing-units calculator HCPCS UNITS

One billing unit of J9358 = 1 mg. Enter a regimen to convert dose → billing units and project a full course.
Billing units = dose ÷ HCPCS unit size. Most payers require whole units — round per the payer's policy. “Est. Medicare pay” uses the current payment limit. For single-dose vials, drug discarded after administration may be separately billable with modifier JW (JZ when none is discarded) where allowed. Always verify payer-specific rounding before billing.

🔁 NDCs that bill under J9358 WITH EST. MEDICARE PAY

1 NDC map to J9358. Bill units = how many HCPCS units one package represents. Est. pay / pkg = payment limit ($32.874/unit) × that package's bill units.
NDC (11-digit)DrugLabelerPackageStrength Bill units Est. pay / pkg NADAC / unit StatusSource
65597-0406-01 Enhertu fam-trastuzumab deruxtecan-nxki 100 mg/5mL INJECTION, POWDER, LYOPHILIZED, FOR SOLUTION Daiichi 1 VIAL, SINGLE-DOSE in 1 CARTON (65597-406... 100 mg/5mL 100 $3,287.40 — ● Active CMS ASP
NDC→HCPCS mappings come from the CMS ASP NDC-HCPCS crosswalk; additional DME MAC / DMEPOS mappings come from PDAC and are labeled separately. NADAC from CMS (weekly). “Status” reflects the product's marketing / obsolete flag in the NDC directory. Presence or absence here does not determine Medicare coverage. Linked NDCs open the full product page.

📊 Medicare utilization & spend CMS · PART B · 2026 (Q1)

Period
Total Part B spend
$209.39M
Claims
18,044
Beneficiaries
6,486
Spend / beneficiary
$32,282.83
Spend / claim
$11,604.21
Trend by period
Where J9358 ranks among Part B drugs · 2026 (Q1) · neighbors ±5
Total spending — #15 of 824
#10 REBLOZYL J0896 $258.35M #11 EYLEA J0178 $249.97M #12 ORENCIA CLICKJECT* J0129 $228.95M #13 PAVBLU Q5147 $222.65M #14 PADCEV J9177 $215.91M #15 ENHERTU J9358 $209.39M #16 GAMMAGARD LIQUID J1569 $182.71M #17 ENTYVIO J3380 $180.78M #18 ULTOMIRIS J1303 $178.93M #19 GAMMAKED* J1561 $164.01M #20 TECENTRIQ J9022 $153.47M
Total claims — #119 of 824
#114 EMEND* J1453 19,071 #115 ALBUKED-25(P9047)* P9047 18,777 #116 MONOFERRIC J1437 18,337 #117 OCTAGAM J1568 18,321 #118 PACLITAXEL J9267 18,259 #119 ENHERTU J9358 18,044 #120 CARBOPLATIN* J9045 18,010 #121 OCTREOTIDE ACETATE E... J2353 17,897 #122 LANREOTIDE ACETATE(J... J1930 17,811 #123 GEMCITABINE HCL(J920... J9201 17,649 #124 NULOJIX J0485 17,290

Full breakdown by period (2)
PeriodTotal spendBeneficiariesClaims$/beneficiary$/claim
2026 (Q1) $209.39M 6,486 18,044 $32,282.83 $11,604.21
2025 (Q1-Q4) $757.95M 10,461 69,370 $72,455.15 $10,926.24
Provider-administered (Part B) spend, calculated for the whole HCPCS code (CMS does not publish Medicare spend per individual NDC). Self-administered use is covered under Part D instead. A blank patient count means fewer than 11 people — CMS hides counts that small to protect privacy. Source: CMS Medicare Quarterly Part B Spending by Drug (data.cms.gov), updated quarterly.

📈 Medicare Part B claims detail CMS PSPS · 2024

Calendar-year 2024 Medicare Part B fee-for-service activity for this HCPCS code, summed across all carriers, localities and specialties (CMS Physician/Supplier Procedure Summary). A “service” is one billed line/unit — not one claim — so counts run higher than claim counts.
Allowed charges
$270.15M
Medicare paid
$209.48M
Submitted services
9,619,903
Denial rate
3.7%
Allowed / service
$29.16
Submitted charges
$694.2M
Source: CMS Physician/Supplier Procedure Summary (PSPS), CY2024 — Medicare Part B carrier + DME fee-for-service claims (excludes Medicare Advantage). Figures are for the whole HCPCS code, which may cover uses beyond this drug. ⚠ CMS hides any figure covering fewer than 11 patients (a privacy rule), so totals — especially denials and low-volume codes — run a little low.

🗺️ Where J9358 is utilized CMS · BY PROVIDER · 2024

Medicare Part B services for this code by the rendering provider's state — 107,900 services across 3 states & territories in 2024 (CMS reports include DC and U.S. territories). Switch to per 100k to compare states fairly regardless of population. Hover or tap a state for its top ZIP codes.
Hover or tap a state to see its numbers + top ZIP codes.
Per-capita = services ÷ 2023 state population × 100,000 (so high-population states aren't automatically "hotter"). Counts reflect the provider's location, not the patient's. Providers with fewer than 11 patients are hidden by CMS for privacy, so totals run low and per-100k can be noisy in small states — read this as relative geography, not exact counts. Source: CMS Medicare Physician & Other Practitioners — by Provider and Service, 2024.

🗃️ Data sources & freshness

Every figure on this page is computed from public datasets. Here's what each section draws on and how current it is.
HCPCS code & descriptor
CMS HCPCS Level II code file
Loaded
Payment limit & billing unit
CMS Medicare Part B ASP Pricing File (quarterly)
Q3 2026 · as of 2026-08-20
NDC ↔ HCPCS crosswalk
CMS ASP NDC-HCPCS crosswalk
1 NDC mapped
NADAC acquisition cost
CMS National Average Drug Acquisition Cost (weekly)
Not available for mapped NDCs
Utilization & spend
CMS Part B Spending by Drug · PSPS · Physician & Other Practitioners
Latest data year 2026
Figures are estimates for reference and may lag the source files. Always verify against the current CMS files and your payer's policy before submitting claims.

⚠️ Practical billing caveats

  • A crosswalk is not coverage. An NDC mapping or a published payment limit does not guarantee a payer will cover or pay this code. Check the specific plan's policy.
  • Units ≠ milligrams. Bill the number of HCPCS units (dose ÷ the code's unit size), not the milligram dose. Use the calculator above.
  • Discarded drug. For single-dose vials, drug discarded after administration may be separately billable with modifier JW (and JZ when nothing is discarded) where the payer allows.
  • Rounding & partial units. Many payers require whole units; round per the payer's policy, not automatically up.
  • The code can cover more than this drug. Some HCPCS codes span multiple products or strengths — confirm the exact code for the product administered.
  • Figures lag. ASP limits change quarterly and utilization data are released with a delay. Verify against the current CMS files before billing.

❓ J9358 billing FAQ

What is HCPCS code J9358?
J9358 is a HCPCS Level II J-code used to bill Injection, fam-trastuzumab deruxtecan-nxki, 1 mg under Medicare Part B and most medical (not pharmacy) benefits.
What is the billing unit for J9358?
One unit of J9358 represents 1 MG. Report the number of units equal to the dose administered divided by 1 MG.
How many units of J9358 should I bill?
Divide the dose administered by the code's unit size (1 MG) to get the number of billing units, then round per your payer's policy. The calculator on this page converts a dose into billing units and projects a full course.
How much does Medicare pay for J9358?
The Medicare Part B payment limit is $32.874 per unit (Q3 2026), based on ASP + 6%. After the 2% sequester the effective payment is about $32.217 per unit. Payment limits are revised quarterly.
Which NDCs bill under J9358?
1 NDC currently map to J9358 in the CMS ASP NDC-HCPCS crosswalk. See the NDC crosswalk table above for each product, package, billing units and estimated reimbursement.
Does a crosswalk mean J9358 is covered?
No. An NDC-to-HCPCS crosswalk and a published payment limit do not guarantee coverage or payment. Coverage depends on the payer, the diagnosis and the site of care — always verify the current policy before billing.
For professional billing reference only — verify against the current CMS files before submitting claims.