Enhertu fam-trastuzumab deruxtecan-nxki 100 mg/5mL Injection, Powder, Lyophilized, For Solution — NDC 65597-406-01 (Billing 65597-0406-01)
This is a package of Enhertu fam-trastuzumab deruxtecan-nxki 100 mg/5mL Injection, Powder, Lyophilized, For Solution from Daiichi Sankyo Inc., marketed since Dec 2019 and currently FDA-listed. It is this product's only package size.
NDC database record
One package, one record: these facts belong to NDC 65597-406-01 alone.
- Record
- FDA NDC Directory package listing · Human prescription drug
- Code segments
- 65597 labeler · 406 product · 01 package
- Package marketed since
- Dec 20, 2019
- Sample package
- No — commercial package
- Listing certified through
- Dec 31, 2027
- Barcode (UPC-A, from the NDC)
- 3 6559740601 8
- Medicaid fills, this package
- 17,540 prescriptions in the last four reported quarters
- FDA record last changed
- Jul 24, 2026
Identity & classification
Regulatory identifiers FDA, NLM and CMS codes for this package
Drug-database identifiers Medi-Span GPI and First Databank GCN / HICL / AHFS classification
- GSN (GCN sequence number): 080576
- GCN: 47458
- GPI-14 (Medi-Span): 21355070552120
- HICL (First Databank): 046262
- AHFS class code: 10:00.00.00
- RxCUI (RxNorm): 2267576
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 8, 2026
- FDA label on DailyMed · label index refreshed Oct 8, 2026
- RxNorm (NLM RxNav) · catalog refreshed Oct 8, 2026
- Medi-Span GPI (licensed)
- First Databank (licensed) · refreshed Oct 8, 2026
RxNorm drug class
This medicine belongs to the HER2/neu Receptor Antagonist class.
Where does this data come from?
- RxClass (NLM) · catalog refreshed Oct 8, 2026
Clinical
- It treats certain HER2-related cancers in adults, including breast, lung and gastric cancers and some solid tumors. Your oncologist confirms your tumor's HER2 status or mutation wi...
- It is given as an IV infusion at a clinic, usually every 3 weeks. You will get anti-nausea medicine beforehand because nausea and vomiting are common.
- Call right away for a new cough, trouble breathing or fever, since these can signal serious lung inflammation. Also report signs of infection or heart problems such as swelling or...
- What symptoms should I call about right away?
Patient education
Supplement & herbal interactions
Where does this data come from?
- MedlinePlus (NLM) · refreshed Oct 8, 2026
- FDA label on DailyMed · label index refreshed Oct 8, 2026
Ask a licensed pharmacist directly — free, answered by our team.
Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per mL | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | Not in the retail survey — common for institutional, discontinued, or low-volume packs. | |
| Medicaid paysCMS SDUD · 12 mo | $2,649.64 | $13,248.18 / 5 ml |
| Medicare drug plans payPart D · quarterly | No Part D plan price is available for this NDC in our data. | |
| Medicare Part B allowsASP · J9358 | $32.874 / J9358 unit | — |
Where does this data come from?
- CMS NADAC weekly file
- CMS ASP pricing files · refreshed Sep 20, 2026
- CMS Medicaid State Drug Utilization Data · through Q1 2026
- CMS Part D plan pricing files · refreshed Sep 24, 2026
- VA National Acquisition Center price file
Billing & reimbursement
Where does this data come from?
- CMS ASP NDC-HCPCS crosswalk · refreshed Sep 22, 2026
- DMEPDAC NDC-HCPCS crosswalk
- openFDA NSDE billing units · refreshed Oct 7, 2026
Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Marketing end | Status |
|---|---|---|---|---|
| 65597-0406-01 You're viewing this Main listing | 1 VIAL, SINGLE-DOSE in 1 CARTON / 5 mL in 1 VIAL, SINGLE-DOSE | 2019-12-20 | — | Active |
Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Enhertu 100 mg/5mLthis 65597-0406-01 | Daiichi | 1 vial | — | — | FDA listed | — |
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 8, 2026
- FDA Purple Book · refreshed Oct 5, 2026
- CMS NADAC weekly file
Availability & biosimilar status
Biologics have no small-molecule generics; biosimilar competition is tracked in the FDA Purple Book.
Why the date isn’t exact: Biosimilar timing can change because patents may be challenged, settled, licensed, added or removed, and litigation can move the real date earlier or later.
🛈 What do these terms mean?
- Biologic patent
- A patent the reference product’s maker has publicly listed. A biosimilar generally can’t launch until these expire — unless they’re invalidated or resolved in a settlement.
- Reference-product exclusivity
- A flat 12 years of FDA market protection from the biologic’s first licensure (the BPCIA). No biosimilar can be licensed before it ends, regardless of patents.
- Interchangeable exclusivity
- The first interchangeable biosimilar can earn a period as the only interchangeable version (pharmacists can substitute it without the prescriber).
- Earliest biosimilar (LOE)
- The latest of all the dates above — the soonest a biosimilar can realistically reach the market. Litigation and settlements can move it earlier.
Biologics have no small-molecule “generics” — competition comes from FDA-licensed biosimilars, tracked in the FDA Purple Book.
| Code | What it grants | Expires |
|---|---|---|
| RefProduct | Reference-product exclusivity (12-year, BPCIA) — no biosimilar can be licensed before this date | Dec 20, 2031 |
Is there a biosimilar for ENHERTU 100 MG VIAL?
Why do different websites show different biosimilar dates?
Can a biosimilar launch before the last patent expires?
What does “current Purple Book estimate” mean?
What does “FDA listed” mean?
What does a patent or protection date mean here?
Where does this data come from?
- FDA Purple Book · refreshed Oct 5, 2026
Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
🧪 Avoiding an ingredient? See Fam-trastuzumab deruxtecan-nxki Injection inactive ingredients by manufacturer: every current product's list side by side, so you can ask your pharmacy for the version that does not list it.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
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UNII 4QD397987E
An amino acid used as a buffer and stabilizer in medications. It helps maintain the pH balance and protects the active drug from breaking down during storage and use.
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UNII X573657P6P
Histidine monohydrochloride monohydrate is an amino acid salt used as a buffer in medicines. It helps maintain the proper acidity level of liquid formulations to keep the drug stable and effective.
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UNII 6OZP39ZG8H
Polysorbate 80 is a synthetic emulsifier derived from sorbitol and oleic acid. It helps mix oil and water-based ingredients together in medications and improves how the product disperses in the body.
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UNII C151H8M554
A natural sugar derived from sugar cane or sugar beets. It's used as a sweetener, filler, and binder to improve taste, add bulk, and help hold tablet or capsule ingredients together.
4 inactive ingredients listed in the exact product block matched to this NDC.
Where does this data come from?
ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.- FDA label on DailyMed · label index refreshed Oct 8, 2026
- FDA openFDA NDC Directory · synced Oct 8, 2026
Inactive ingredient FAQ
Are inactive ingredients the same for every manufacturer?
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Can inactive ingredients matter?
Manufacturer & labeler
More NDCs from Daiichi Sankyo Inc. labeler code 65597
- Savaysa Edoxaban Tosylate 15 mg Tablet, Film Coated NDC 65597-201-07
- Savaysa Edoxaban Tosylate 30 mg Tablet, Film Coated NDC 65597-202-05
- Savaysa Edoxaban Tosylate 60 mg Tablet, Film Coated NDC 65597-203-05
- Turalio pexidartinib hydrochloride 125 mg Capsule NDC 65597-407-20
- Vanflyta Quizartinib 17.7 mg Tablet, Film Coated NDC 65597-504-04
- Vanflyta Quizartinib 26.5 mg Tablet, Film Coated NDC 65597-511-04
- DATROWAY Datopotamab Deruxtecan 100 mg/5mL Injection, Powder, Lyophilized, For Solution NDC 65597-801-01
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 8, 2026
- Drugs@FDA
Full prescribing information FDA SPL
🚨 Boxed Warning ▾
WARNING: INTERSTITIAL LUNG DISEASE and EMBRYO-FETAL TOXICITY Interstitial Lung Disease (ILD) and pneumonitis, including severe, life-threatening, and fatal cases, have been reported with ENHERTU. Monitor for and promptly investigate signs and symptoms including cough, dyspnea, fever, and other new or worsening respiratory symptoms. Permanently discontinue ENHERTU in all patients with Grade 2 or higher ILD/pneumonitis.
Advise patients of the risk and the need to immediately report symptoms [see Dosage and Administration (2.3) , Warnings and Precautions (5.1) ] . Embryo-Fetal Toxicity: Exposure to ENHERTU during pregnancy can cause embryo-fetal harm. Advise patients of these risks and the need for effective contraception [see Warnings and Precautions (5.4) , Use in Specific Populations (8.1 , 8.3) ] .
WARNING: INTERSTITIAL LUNG DISEASE and EMBRYO-FETAL TOXICITY See full prescribing information for complete boxed warning. Interstitial lung disease (ILD) and pneumonitis, including severe, life threatening, and fatal cases, have been reported with ENHERTU. Monitor for and promptly investigate signs and symptoms including cough, dyspnea, fever, and other new or worsening respiratory symptoms.
Permanently discontinue ENHERTU in all patients with Grade 2 or higher ILD/pneumonitis. Advise patients of the risk and to immediately report symptoms. ( 2.3 , 5.1 ) Exposure to ENHERTU during pregnancy can cause embryo-fetal harm.
Advise patients of these risks and the need for effective contraception. ( 5.4 , 8.1 , 8.3 )
🎯 Indications and Usage ▾
1 INDICATIONS AND USAGE ENHERTU is a HER2-directed antibody and topoisomerase inhibitor conjugate indicated for: HER2-Positive Early Breast Cancer as neoadjuvant treatment of adult patients with HER2-positive (IHC 3+ or ISH+) Stage II or III breast cancer, as determined by an FDA-authorized test followed by a taxane, trastuzumab, and pertuzumab (THP). ( 1.1 ) as adjuvant treatment of adult patients with HER2-positive (IHC 3+ or ISH+) breast cancer who have residual invasive disease following neoadjuvant trastuzumab (with or without pertuzumab) and taxane-based treatment.
( 1.1 ) HER2-Positive Metastatic Breast Cancer in combination with pertuzumab as first-line treatment of adult patients with unresectable or metastatic HER2-positive (IHC 3+ or ISH+) breast cancer, as determined by an FDA-authorized test. ( 1.2 ) as monotherapy for the treatment of adult patients with unresectable or metastatic HER2-positive (IHC 3+ or ISH+) breast cancer who have received a prior anti-HER2-based regimen either in the metastatic setting, or, in the neoadjuvant or adjuvant setting and have developed disease recurrence during or within six months of completing therapy.
( 1.2 ) HER2-Low and HER2-Ultralow Metastatic Breast Cancer as monotherapy for the treatment of adult patients with unresectable or metastatic hormone receptor (HR)-positive, HER2-low (IHC 1+ or IHC 2+/ISH-) or HER2-ultralow (IHC 0 with membrane staining) breast cancer, as determined by an FDA-authorized test, that has progressed on one or more endocrine therapies in the metastatic setting. ( 1.3 ) as monotherapy for the treatment of adult patients with unresectable or metastatic HER2-low (IHC 1+ or IHC 2+/ISH-) breast cancer, as determined by an FDA-authorized test, who have received a prior chemotherapy in the metastatic setting; or developed disease recurrence during or within 6 months of completing adjuvant chemotherapy.
( 1.3 ) HER2-Mutant Unresectable or Metastatic Non-Small Cell Lung Cancer as monotherapy for the treatment of adult patients with unresectable or metastatic non-small cell lung cancer (NSCLC) whose tumors have activating HER2 (ERBB2) mutations, as detected by an FDA-authorized test, and who have received a prior systemic therapy* ( 1.4 ) HER2-Positive Locally Advanced or Metastatic Gastric Cancer as monotherapy for the treatment of adult patients with locally advanced or metastatic HER2-positive (IHC 3+ or IHC 2+/ISH positive) gastric or gastroesophageal junction adenocarcinoma who have received a prior trastuzumab-based regimen.
( 1.5 ) HER2-Positive (IHC 3+) Unresectable or Metastatic Solid Tumors as monotherapy for the treatment of adult patients with unresectable or metastatic HER2-positive (IHC 3+) solid tumors who have received prior systemic treatment and have no satisfactory alternative treatment options* ( 1.6 ) * These indications are approved under accelerated approval based on objective response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial.
( 14.3 , 14.5 )
1.1HER2-Positive Early Breast Cancer ENHERTU followed by a taxane, trastuzumab, and pertuzumab (THP) is indicated for the neoadjuvant treatment of adult patients with HER2-positive (IHC 3+ or ISH+) Stage II or III breast cancer as determined by an FDA-authorized test [see Dosage and Administration (2.1) ]. ENHERTU is indicated for the adjuvant treatment of adult patients with HER2-positive (IHC 3+ or ISH+) breast cancer who have residual invasive disease following neoadjuvant trastuzumab (with or without pertuzumab) and taxane-based treatment.
1.2HER2-Positive Metastatic Breast Cancer ENHERTU, in combination with pertuzumab, is indicated for the first-line treatment of adult patients with unresectable or metastatic HER2-positive (IHC 3+ or ISH+) breast cancer, as determined by an FDA-authorized test [see Dosage and Administration (2.1) ]. ENHERTU, as monotherapy, is indicated… [Excerpted — this section continues on DailyMed.]
⏱️ Dosage and Administration ▾
2 DOSAGE AND ADMINISTRATION Do not substitute ENHERTU for or with trastuzumab or ado-trastuzumab emtansine. ( 2.2 , 2.4 ) For intravenous infusion only . Do not administer as an intravenous push or bolus.
DO NOT use Sodium Chloride Injection, USP. ( 2.4 ) Premedicate for prevention of chemotherapy-induced nausea and vomiting. ( 2.2 ) HER2-Positive Early Breast Cancer Neoadjuvant: ENHERTU 5.4 mg/kg every 3 weeks for 4 cycles, followed by THP regimen for 4 cycles.
( 2.2 , 2.3 ) Post Neoadjuvant: ENHERTU 5.4 mg/kg every 3 weeks for 14 cycles unless disease recurrence or unacceptable toxicity. ( 2.2 , 2.3 ) HER2-Positive, HER2-Low, or HER2-Ultralow Breast Cancer, HER2-Mutant NSCLC, and HER2-Positive (IHC 3+) Solid Tumors: ENHERTU 5.4 mg/kg every 3 weeks until disease progression or unacceptable toxicity. ( 2.2 , 2.3 ) HER2-Positive First-line Metastatic Breast Cancer: ENHERTU 5.4 mg/kg every 3 weeks in combination with pertuzumab until disease progression or unacceptable toxicity.
Cycle 1, Day 1: ENHERTU 5.4 mg/kg followed by pertuzumab 840 mg. ( 2.2 , 2.3 ) Subsequent cycles, Day 1: ENHERTU 5.4 mg/kg followed by pertuzumab 420 mg. ( 2.2 , 2.3 ) HER2-Positive Gastric Cancer: 6.4 mg/kg every 3 weeks until disease progression or unacceptable toxicity.
( 2.2 , 2.3 ) Management of adverse reactions (ILD, neutropenia, thrombocytopenia, or left ventricular dysfunction) may require temporary interruption, dose reduction, or discontinuation of ENHERTU. ( 2.3 )
2.1Patient Selection HER2-Positive Early Breast Cancer Select patients for the treatment of HER2-positive early breast cancer with ENHERTU based on HER2-positive (IHC 3+ or ISH+) status [see Clinical Studies (14.1) ]. HER2-Positive Metastatic Breast Cancer Select patients for treatment of unresectable or metastatic HER2-positive breast cancer with ENHERTU in combination with pertuzumab based on confirmed HER2-positive status or HER2 gene amplification (IHC 3+ or ISH+) [see Clinical Studies (14.2) ] . HER2-Low or HER2-Ultralow Unresectable or Metastatic Breast Cancer Select patients for treatment of unresectable or metastatic HER2-low (IHC 1+ or IHC 2+/ISH-) or HER2-ultralow (IHC 0 with membrane staining) breast cancer with ENHERTU based on HER2 expression [see Clinical Studies (14.3) ] .
HER2-Mutant Unresectable or Metastatic NSCLC Select patients for the treatment of unresectable or metastatic HER2-mutant NSCLC with ENHERTU based on the presence of activating HER2 (ERBB2) mutations in tumor or plasma specimens [see Clinical Studies (14.4) ] . If no mutation is detected in a plasma specimen, test tumor tissue. HER2-Positive Locally Advanced or Metastatic Gastric Cancer Select patients with locally advanced or metastatic HER2-positive gastric cancer based on HER2 protein overexpression or HER2 gene amplification (IHC 3+ or IHC 2+/ISH+).
Reassess HER2 status if it is feasible to obtain a new tumor specimen after prior trastuzumab-based therapy and before treatment with ENHERTU. HER2-Positive (IHC 3+) Unresectable or Metastatic Solid Tumors Select patients for treatment of unresectable or metastatic solid tumors with ENHERTU based on HER2-positive (IHC 3+) specimens [see Clinical Studies (14.6) ] . An FDA-authorized test for the detection of HER2-positive (IHC 3+) solid tumors for treatment with ENHERTU is not currently available.
Additional Patient Selection Information Information on FDA-authorized tests for the detection of HER2 protein expression, HER2 gene amplification, and activating HER2 mutations is available at: http://www.fda.gov/CompanionDiagnostics.
2.2Recommended Dosage Do not substitute ENHERTU for or with trastuzumab or ado-trastuzumab emtansine. Slow or interrupt the infusion rate if the patient develops infusion-related symptoms. Permanently discontinue ENHERTU in case of severe infusion reactions.
Premedication ENHERTU is highly emetogenic [see Adverse Reactions (6.1) ] , which includes delayed nausea and/or vomiting. Administer prophylactic antiemetic medications… [Excerpted — this section continues on DailyMed.]
💊 Dosage Forms and Strengths ▾
3 DOSAGE FORMS AND STRENGTHS For injection: 100 mg of fam-trastuzumab deruxtecan-nxki as a white to yellowish white lyophilized powder in a single-dose vial for reconstitution and further dilution For injection: 100 mg lyophilized powder in a single-dose vial ( 3 )
⛔ Contraindications ▾
4 CONTRAINDICATIONS None . None. ( 4 )
⚠️ Warnings and Cautions ▾
5 WARNINGS AND PRECAUTIONS Neutropenia: Monitor complete blood counts prior to initiation of ENHERTU and prior to each dose, and as clinically indicated. Manage through treatment interruption or dose reduction. ( 2.3 , 5.2 ) Left Ventricular Dysfunction (LVD): Assess left ventricular ejection fraction (LVEF) prior to initiation of ENHERTU and at regular intervals during treatment as clinically indicated.
Manage through treatment interruption or discontinuation. Permanently discontinue ENHERTU in patients with symptomatic congestive heart failure (CHF). ( 2.3 , 5.3 )
5.1Interstitial Lung Disease/Pneumonitis Severe, life-threatening, or fatal interstitial lung disease (ILD), including pneumonitis, can occur in patients treated with ENHERTU [see Adverse Reactions (6.1) ] . A higher incidence of Grade 1 and 2 ILD/pneumonitis has been observed in patients with moderate renal impairment. Advise patients to immediately report cough, dyspnea, fever, and/or any new or worsening respiratory symptoms.
Monitor patients for signs and symptoms of ILD. Promptly investigate evidence of ILD. Evaluate patients with suspected ILD by radiographic imaging.
Consider consultation with a pulmonologist. For asymptomatic (Grade 1) ILD, consider corticosteroid treatment (e.g., ≥0.5 mg/kg/day prednisolone or equivalent). Withhold ENHERTU until recovery [see Dosage and Administration (2.3) ] .
In cases of symptomatic ILD (Grade 2 or greater), promptly initiate systemic corticosteroid treatment (e.g., ≥1 mg/kg/day prednisolone or equivalent) and continue for at least 14 days followed by gradual taper for at least 4 weeks. Permanently discontinue ENHERTU in patients who are diagnosed with symptomatic (Grade 2 or greater) ILD [see Dosage and Administration (2.3) ] . HER2-Positive, HER2-Low, and HER2-Ultralow Breast Cancer, HER2-Mutant NSCLC, and Solid Tumors (Including IHC 3+) (5.4 mg/kg) ENHERTU as Monotherapy In patients treated with ENHERTU 5.4 mg/kg, ILD occurred in 12% of patients.
Median time to first onset was 5.5 months (range: 0.9 to 31.5). Fatal outcomes due to ILD and/or pneumonitis occurred in 0.9% of patients treated with ENHERTU. ENHERTU in Combination with Pertuzumab In patients treated with ENHERTU 5.4 mg/kg in combination with pertuzumab (N=431), ILD occurred in 12% of patients.
Median time to first onset was 8.0 months (range: 0.6 to 33.8). Fatal outcomes due to ILD and/or pneumonitis occurred in 0.5% of patients treated with ENHERTU in combination with pertuzumab. ENHERTU followed by THP In patients treated with ENHERTU 5.4 mg/kg followed by THP in DESTINY-Breast11, ILD occurred in 4.4% of patients.
Median time to first onset was 2.7 months (range: 1.1 to 6.0). Fatal outcomes due to ILD and/or pneumonitis occurred in one patient (0.3%) treated with ENHERTU followed by THP. HER2-Positive Locally Advanced or Metastatic Gastric Cancer (6.4 mg/kg) In patients with locally advanced or metastatic HER2-positive gastric or GEJ adenocarcinoma treated with ENHERTU 6.4 mg/kg, ILD occurred in 10% of patients.
Median time to first onset was 2.8 months (range: 1.2 to 21).
5.2Neutropenia Severe neutropenia, including febrile neutropenia, can occur in patients treated with ENHERTU. Monitor complete blood counts prior to initiation of ENHERTU and prior to each dose, and as clinically indicated. Based on the severity of neutropenia, ENHERTU may require dose interruption or reduction [see Dosage and Administration (2.3) ] .
HER2-Positive, HER2-Low, and HER2-Ultralow Breast Cancer, HER2-Mutant NSCLC, and Solid Tumors (Including IHC 3+) (5.4 mg/kg) ENHERTU as Monotherapy In patients treated with ENHERTU 5.4 mg/kg, a decrease in neutrophil count was reported in 65% of patients. Nineteen percent had Grade 3 or 4 decreased neutrophil count. Median time to first onset of decreased neutrophil count was 22 days (range: 2 to 939).
Febrile neutropenia was reported in 1% of patients. ENHERTU in Combination with Pertuzumab In patients treated with ENHERTU 5.4 mg/kg in… [Excerpted — this section continues on DailyMed.]
🤒 Adverse Reactions ▾
6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: Interstitial Lung Disease/Pneumonitis [see Warnings and Precautions (5.1) ] Neutropenia [see Warnings and Precautions (5.2) ] Left Ventricular Dysfunction [see Warnings and Precautions (5.3) ] The most common adverse reactions (≥20%), including laboratory abnormalities, in patients with: HER2-Positive, HER2-Low, and HER2-Ultralow Breast Cancer, HER2-Mutant NSCLC, and HER2-Positive (including IHC 3+) Solid Tumors are decreased white blood cell count, nausea, decreased hemoglobin, decreased neutrophil count, decreased lymphocyte count, fatigue, decreased platelet count, increased aspartate aminotransferase, increased alanine aminotransferase, increased blood alkaline phosphatase, vomiting, alopecia, constipation, decreased blood potassium, decreased appetite, diarrhea, and musculoskeletal pain.
( 6.1 ) HER2-Positive Early Breast Cancer are decreased hemoglobin, increased alanine aminotransferase, increased aspartate aminotransferase, decreased white blood cell count, nausea, peripheral neuropathy, diarrhea, decreased neutrophil count, alopecia, fatigue, decreased lymphocyte count, rash, musculoskeletal pain, decreased blood potassium, constipation, vomiting, stomatitis, and decreased appetite. ( 6.1 ) HER2-Positive Metastatic Breast Cancer in Combination with Pertuzumab are decreased white blood cell count, decreased hemoglobin, decreased neutrophil count, nausea, increased alanine aminotransferase, diarrhea, increased aspartate aminotransferase, decreased lymphocyte count, decreased platelet count, increased blood alkaline phosphatase, decreased blood potassium, fatigue, alopecia, vomiting, upper respiratory tract infection, constipation, decreased appetite, decreased weight, COVID-19, musculoskeletal pain, increased blood bilirubin, and abdominal pain.
( 6.1 ) HER2-Positive Gastric Cancer are decreased hemoglobin, decreased white blood cell count, decreased neutrophil count, decreased lymphocyte count, decreased platelet count, nausea, decreased appetite, increased aspartate aminotransferase, fatigue, increased blood alkaline phosphatase, increased alanine aminotransferase, diarrhea, decreased blood potassium, vomiting, constipation, increased blood bilirubin, pyrexia, and alopecia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Daiichi Sankyo, Inc. at 1-877-437-7763 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
6.1Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. HER2-Positive, HER2-Low, and HER2-Ultralow Breast Cancer, HER2-Mutant NSCLC, and Solid Tumors (Including IHC 3+) (5.4 mg/kg) ENHERTU as Monotherapy The pooled safety population described in WARNINGS and PRECAUTIONS reflects exposure to ENHERTU 5.4 mg/kg intravenously every 3 weeks in 2233 patients in Study DS8201-A-J101 (NCT02564900), DESTINY-Breast01, DESTINY-Breast02, DESTINY-Breast03, DESTINY-Breast04, DESTINY-Breast06, DESTINY-Lung01, DESTINY-Lung02, DESTINY-CRC02, and DESTINY-PanTumor02.
Among these patients, 67% were exposed for greater than 6 months and 39% were exposed for greater than 12 months. In this pooled safety population, the most common (≥20%) adverse reactions (including laboratory abnormalities) were decreased white blood cell count (73%), nausea (72%), decreased hemoglobin (67%), decreased neutrophil count (65%), decreased lymphocyte count (60%), fatigue (55%), decreased platelet count (48%), increased aspartate aminotransferase (46%), increased alanine aminotransferase (43%), increased blood alkaline phosphatase (39%), vomiting (38%), alopecia (37%), constipation (32%), decreased blood potassium (32%), decreased appetite (31%), diarrhea (30%), and musculoskeletal pain (24%).
ENHERTU… [Excerpted — this section continues on DailyMed.]
👥 Use in Specific Populations ▾
8 USE IN SPECIFIC POPULATIONS Lactation: Advise not to breastfeed. (8.2) Females and Males of Reproductive Potential: Verify pregnancy status of females prior to initiation of ENHERTU. ( 8.3 )
8.1Pregnancy Risk Summary Based on its mechanism of action, ENHERTU can cause fetal harm when administered to a pregnant woman. There are no available data on the use of ENHERTU in pregnant women. In postmarketing reports, use of a HER2-directed antibody during pregnancy resulted in cases of oligohydramnios manifesting as fatal pulmonary hypoplasia, skeletal abnormalities, and neonatal death ( see Data ).
Based on its mechanism of action, the topoisomerase inhibitor component of ENHERTU, DXd, can also cause embryo-fetal harm when administered to a pregnant woman because it is genotoxic and targets actively dividing cells [see Clinical Pharmacology (12.1) , Nonclinical Toxicology (13.1) ] . Advise patients of the potential risks to a fetus. There are clinical considerations if ENHERTU is used in pregnant women, or if a patient becomes pregnant within 7 months after the last dose of ENHERTU ( see Clinical Considerations ).
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.
Clinical Considerations Fetal/Neonatal Adverse Reactions Monitor women who received ENHERTU during pregnancy or within 7 months prior to conception for oligohydramnios. If oligohydramnios occurs, perform fetal testing that is appropriate for gestational age and consistent with community standards of care. Data Human Data There are no available data on the use of ENHERTU in pregnant women.
In postmarketing reports in pregnant women receiving a HER2-directed antibody, cases of oligohydramnios manifesting as fatal pulmonary hypoplasia, skeletal abnormalities, and neonatal death have been reported. These case reports described oligohydramnios in pregnant women who received a HER2-directed antibody either alone or in combination with chemotherapy. In some case reports, amniotic fluid index increased after use of a HER2-directed antibody was stopped.
Animal Data There were no animal reproductive or developmental toxicity studies conducted with fam-trastuzumab deruxtecan-nxki.
8.2Lactation Risk Summary There is no data regarding the presence of fam-trastuzumab deruxtecan-nxki in human milk, the effects on the breastfed child, or the effects on milk production. Because of the potential for serious adverse reactions in a breastfed child, advise women not to breastfeed during treatment with ENHERTU and for 7 months after the last dose.
8.3Females and Males of Reproductive Potential Pregnancy Testing Verify pregnancy status of females of reproductive potential prior to initiation of ENHERTU. Contraception Females ENHERTU can cause fetal harm when administered to a pregnant woman [see Use in Specific Populations (8.1) ] . Advise females of reproductive potential to use effective contraception during treatment with ENHERTU and for 7 months after the last dose.
Males Because of the potential for genotoxicity, advise male patients with female partners of reproductive potential to use effective contraception during treatment with ENHERTU and for 4 months after the last dose [see Nonclinical Toxicology (13.1) ] . Infertility Based on findings in animal toxicity studies, ENHERTU may impair male reproductive function and fertility [see Nonclinical Toxicology (13.1) ] .
8.4Pediatric Use Safety and effectiveness of ENHERTU have not been established in pediatric patients. Animal Data Juvenile animal studies have not been conducted with fam-trastuzumab deruxtecan-nxki. In a six-week repeat-dose toxicity study in rats, intravenous administration of fam-trastuzumab deruxt… [Excerpted — this section continues on DailyMed.]
🤰 Pregnancy ▾
8.1Pregnancy Risk Summary Based on its mechanism of action, ENHERTU can cause fetal harm when administered to a pregnant woman. There are no available data on the use of ENHERTU in pregnant women. In postmarketing reports, use of a HER2-directed antibody during pregnancy resulted in cases of oligohydramnios manifesting as fatal pulmonary hypoplasia, skeletal abnormalities, and neonatal death ( see Data ).
Based on its mechanism of action, the topoisomerase inhibitor component of ENHERTU, DXd, can also cause embryo-fetal harm when administered to a pregnant woman because it is genotoxic and targets actively dividing cells [see Clinical Pharmacology (12.1) , Nonclinical Toxicology (13.1) ] . Advise patients of the potential risks to a fetus. There are clinical considerations if ENHERTU is used in pregnant women, or if a patient becomes pregnant within 7 months after the last dose of ENHERTU ( see Clinical Considerations ).
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.
Clinical Considerations Fetal/Neonatal Adverse Reactions Monitor women who received ENHERTU during pregnancy or within 7 months prior to conception for oligohydramnios. If oligohydramnios occurs, perform fetal testing that is appropriate for gestational age and consistent with community standards of care. Data Human Data There are no available data on the use of ENHERTU in pregnant women.
In postmarketing reports in pregnant women receiving a HER2-directed antibody, cases of oligohydramnios manifesting as fatal pulmonary hypoplasia, skeletal abnormalities, and neonatal death have been reported. These case reports described oligohydramnios in pregnant women who received a HER2-directed antibody either alone or in combination with chemotherapy. In some case reports, amniotic fluid index increased after use of a HER2-directed antibody was stopped.
Animal Data There were no animal reproductive or developmental toxicity studies conducted with fam-trastuzumab deruxtecan-nxki.
🧒 Pediatric Use ▾
8.4Pediatric Use Safety and effectiveness of ENHERTU have not been established in pediatric patients. Animal Data Juvenile animal studies have not been conducted with fam-trastuzumab deruxtecan-nxki. In a six-week repeat-dose toxicity study in rats, intravenous administration of fam-trastuzumab deruxtecan-nxki resulted in incisor tooth toxicity including single cell necrosis in the base area (e.g., ameloblasts, odontoblasts) and degeneration of the enamel at ≥60 mg/kg (approximately ≥9 times the human recommended dose of 5.4 mg/kg based on AUC), abnormal formation or hypoplasia of the dentin, hemorrhage in the sub-enamel organ tissue, and focal lack of the cementum at 197 mg/kg (approximately 19 times the human recommended dose of 5.4 mg/kg based on AUC).
Degeneration of the enamel organ, abnormal dentin formation, hemorrhage in the sub-enamel organ tissue, focal lack of the cementum, and root fracture were observed at 197 mg/kg following a 9-week recovery period.
🧓 Geriatric Use ▾
8.5Geriatric Use ENHERTU as Monotherapy Of the 2233 patients treated with ENHERTU 5.4 mg/kg, 28% were 65 years or older and 6% were 75 years or older. No overall differences in efficacy within clinical studies were observed between patients ≥65 years of age compared to younger patients. There was a higher incidence of Grade 3-4 adverse reactions observed in patients aged 65 years or older (56%) as compared to younger patients (49%).
Of the 125 patients with HER2-positive locally advanced or metastatic gastric or GEJ adenocarcinoma treated with ENHERTU 6.4 mg/kg in DESTINY-Gastric01, 56% were 65 years or older and 14% were 75 years or older. No overall differences in efficacy or safety were observed between patients ≥65 years of age compared to younger patients. ENHERTU in Combination with Pertuzumab In patients with HER2-positive unresectable or metastatic breast cancer treated with ENHERTU 5.4 mg/kg in combination with pertuzumab (N=431), 17% were 65 years or older and 3% were 75 years or older.
No overall differences in efficacy or safety were observed between patients ≥65 years of age compared to younger patients. ENHERTU followed by THP Of the 320 patients with HER2-positive early breast cancer treated with ENHERTU 5.4 mg/kg followed by THP, 12% were 65 years or older and 1.6% were 75 years or older. No overall difference in efficacy was observed between patients ≥65 years of age compared to younger patients.
There was a higher incidence of Grade 3-4 adverse reactions observed in patients aged 65 years or older (38%) as compared to younger patients (30%).
🧬 Clinical Pharmacology ▾
12 CLINICAL PHARMACOLOGY
12.1Mechanism of Action Fam-trastuzumab deruxtecan-nxki is a HER2-directed antibody-drug conjugate. The antibody is a humanized anti-HER2 IgG1. The small molecule, DXd, is a topoisomerase I inhibitor attached to the antibody by a cleavable linker.
Following binding to HER2 on tumor cells, fam-trastuzumab deruxtecan-nxki undergoes internalization and intracellular linker cleavage by lysosomal enzymes. Upon release, the membrane-permeable DXd causes DNA damage and apoptotic cell death.
12.2Pharmacodynamics Exposure-Response Relationships Exposure-response relationship for efficacy has not been fully characterized. Higher systemic exposure to fam-trastuzumab deruxtecan-nxki was associated with a higher incidence rate of any grade ILD. Cardiac Electrophysiology At the dosage of ENHERTU 6.4 mg/kg every 3 weeks, a mean increase in the QTc interval >20 ms was not observed.
12.3Pharmacokinetics The pharmacokinetics of fam-trastuzumab deruxtecan-nxki and its payload DXd were evaluated in patients with cancer and are presented as mean (% coefficient of variation), unless otherwise specified. At a dose of 5.4 mg/kg, the maximum concentration (C max ss ) of fam-trastuzumab deruxtecan-nxki is 132 µg/mL (20%) and of DXd is 4.7 ng/mL (48%) and the AUC ss of fam-trastuzumab deruxtecan-nxki is 772 µg∙day/mL (27%) and of DXd is 29 ng∙day/mL (48%). At a dose of 6.4 mg/kg, the C max,ss of fam-trastuzumab deruxtecan-nxki is 126 µg/mL (18%) and of DXd is 5.2 ng/mL (42%) and the AUC ss of fam-trastuzumab deruxtecan-nxki is 743 µg∙day/mL (26%) and of DXd is 33 ng∙day/mL (43%), respectively.
Following a single dose, C max and AUC of fam-trastuzumab deruxtecan-nxki and DXd increase in a dose proportional manner over a dose range of 3.2 mg/kg to 8 mg/kg (approximately 0.5 to 1.25 times the highest approved dose). Accumulation of fam-trastuzumab deruxtecan-nxki is approximately 1.4-fold at steady-state (Cycle 3). Distribution The estimated volume of distribution of the central compartment (Vc) of fam-trastuzumab deruxtecan-nxki is
2.7L (% CV 16%). DXd plasma protein binding is approximately 97% and the blood-to-plasma ratio is approximately 0.6 in vitro. Elimination The median elimination half-life of fam-trastuzumab deruxtecan-nxki is 5.4 to 5.7 days. The estimated systemic clearance of fam-trastuzumab deruxtecan-nxki is
0.4L/day (24%). The median elimination half-life of DXd is 5.4-6.1 days. The estimated systemic clearance of DXd is 18 L/h (28%).
Metabolism The monoclonal antibody is expected to be degraded into small peptides and amino acids via catabolic pathways. DXd is primarily metabolized by CYP3A4. Specific Populations No clinically significant differences in the pharmacokinetics of fam-trastuzumab deruxtecan-nxki or DXd were observed for age (20-96 years); race (Asian [48%] vs Non-Asian [52%]), including White (43%), and Black or African American (1.9%); sex; body weight (27-138 kg); tumor types; mild hepatic impairment; and mild or moderate renal impairment.
The pharmacokinetics of fam-trastuzumab deruxtecan-nxki or DXd in patients with moderate to severe hepatic impairment or severe renal impairment is unknown. Drug Interaction Studies Clinical Studies No clinically significant differences in pharmacokinetics of fam-trastuzumab deruxtecan-nxki or DXd were observed when used concomitantly with itraconazole (strong CYP3A inhibitor) or ritonavir (strong CYP3A inhibitor and OATP inhibitor). In Vitro Studies CYP450 Enzymes : DXd does not inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A nor induce CYP1A2, CYP2B6, or CYP3A.
UGT Enzymes: DXd is not a substrate of UGT. Transporter Systems : DXd is not an inhibitor of OAT1, OAT3, OCT1, OCT2, OATP1B1, OATP1B3, MATE1, MATE2-K, P-gp, BCRP, or BSEP. DXd is a substrate of OATP1B1, OATP1B3, MATE2-K, P-gp, MRP1, and BCRP.
12.6Immunogenicity The observed incidence of anti-drug antibodies (ADA) is highly dependent on the sensitivity and specificity of the assay.… [Excerpted — this section continues on DailyMed.]
🧬 Mechanism of Action ▾
12.1Mechanism of Action Fam-trastuzumab deruxtecan-nxki is a HER2-directed antibody-drug conjugate. The antibody is a humanized anti-HER2 IgG1. The small molecule, DXd, is a topoisomerase I inhibitor attached to the antibody by a cleavable linker.
Following binding to HER2 on tumor cells, fam-trastuzumab deruxtecan-nxki undergoes internalization and intracellular linker cleavage by lysosomal enzymes. Upon release, the membrane-permeable DXd causes DNA damage and apoptotic cell death.
📦 How Supplied / Storage and Handling ▾
16 HOW SUPPLIED/STORAGE AND HANDLING How Supplied/Storage ENHERTU (fam-trastuzumab deruxtecan-nxki) for injection is a white to yellowish white lyophilized powder supplied as: Carton Contents NDC One 100 mg single-dose vial NDC 65597-406-01 Store vials in a refrigerator at 2°C to 8°C (36°F to 46°F) in the original carton to protect from light until time of reconstitution. Do not freeze. Do not shake the reconstituted or diluted solution [see Dosage and Administration (2.4) ] .
Special Handling ENHERTU (fam-trastuzumab deruxtecan-nxki) is a hazardous drug. Follow applicable special handling and disposal procedures. 1
📦 Storage and Handling ▾
Store vials in a refrigerator at 2°C to 8°C (36°F to 46°F) in the original carton to protect from light until time of reconstitution. Do not freeze. Do not shake the reconstituted or diluted solution [see Dosage and Administration (2.4) ] . Special Handling ENHERTU (fam-trastuzumab deruxtecan-nxki) is a hazardous drug. Follow applicable special handling and disposal procedures. 1
📋 Description ▾
11 DESCRIPTION Fam-trastuzumab deruxtecan-nxki is a HER2-directed antibody and topoisomerase inhibitor conjugate. Fam-trastuzumab deruxtecan-nxki is an antibody-drug conjugate (ADC) composed of three components: 1) a humanized anti-HER2 IgG1 monoclonal antibody (mAb), covalently linked to 2) a topoisomerase I inhibitor, via 3) a tetrapeptide-based cleavable linker. Deruxtecan is composed of a protease-cleavable maleimide tetrapeptide linker and the topoisomerase inhibitor, DXd, which is an exatecan derivative.
The antibody is produced in Chinese hamster ovary cells by recombinant DNA technology, and the topoisomerase inhibitor and linker are produced by chemical synthesis. Approximately 8 molecules of deruxtecan are attached to each antibody molecule. Fam-trastuzumab deruxtecan-nxki has the following structure: ENHERTU (fam-trastuzumab deruxtecan-nxki) is a sterile, white to yellowish white, preservative-free lyophilized powder in single-dose vials.
Each vial delivers 100 mg of fam-trastuzumab deruxtecan-nxki, L-histidine (4.45 mg), L-histidine hydrochloride monohydrate (20.2 mg), polysorbate 80 (1.5 mg), and sucrose (450 mg). Following reconstitution with 5 mL of Sterile Water for Injection, USP, the resulting concentration of fam-trastuzumab deruxtecan-nxki is 20 mg/mL with a pH of 5.5. The resulting solution is administered by intravenous infusion following dilution.
Chemical Structure
💬 Information for Patients ▾
17 PATIENT COUNSELING INFORMATION Advise the patient to read the FDA-approved patient labeling (Medication Guide). Interstitial Lung Disease Inform patients of the risks of severe or fatal ILD. Advise patients to contact their healthcare provider immediately for any of the following: cough, shortness of breath, fever, or other new or worsening respiratory symptoms [see Warnings and Precautions (5.1) ] .
Neutropenia Advise patients of the possibility of developing neutropenia and to immediately contact their healthcare provider should they develop a fever, particularly in association with any signs of infection [see Warnings and Precautions (5.2) ] . Left Ventricular Dysfunction Advise patients to contact their healthcare provider immediately for any of the following: new onset or worsening shortness of breath, cough, fatigue, swelling of ankles/legs, palpitations, sudden weight gain, dizziness, loss of consciousness [see Warnings and Precautions (5.3) ] .
Embryo-Fetal Toxicity Inform female patients of the potential risk to a fetus. Advise female patients to contact their healthcare provider of a known or suspected pregnancy [see Warnings and Precautions (5.4) , Use in Specific Populations (8.1) ] . Advise females of reproductive potential to use effective contraception during treatment with ENHERTU and for 7 months after the last dose [see Use in Specific Populations (8.3) ] .
Advise male patients with female partners of reproductive potential to use effective contraception during treatment with ENHERTU and for 4 months after the last dose [see Use in Specific Populations (8.3) ] . Lactation Advise women not to breastfeed during treatment and for 7 months after the last dose of ENHERTU [see Use in Specific Populations (8.2) ] . Infertility Advise males of reproductive potential that ENHERTU may impair fertility [see Use in Specific Populations (8.3) ] .
💬 Medication Guide ▾
This Medication Guide has been approved by the U.S. Food and Drug Administration. Revised: 05/2026 Medication Guide ENHERTU ® (en-HER-too) (fam-trastuzumab deruxtecan-nxki) for injection What is the most important information I should know about ENHERTU?
ENHERTU can cause serious side effects, including: Lung problems that may be severe, life-threatening or that may lead to death. If you develop lung problems your healthcare provider may treat you with corticosteroid medicines. Tell your healthcare provider right away if you get any of the following signs and symptoms: cough trouble breathing or shortness of breath fever other new or worsening breathing symptoms (such as chest tightness, wheezing) Low white blood cell count (neutropenia).
Low white blood cell counts are common with ENHERTU and can sometimes be severe. Your healthcare provider will check your white blood cell counts before starting ENHERTU and before starting each dose. Tell your healthcare provider right away if you develop any signs or symptoms of an infection or have fever or chills during treatment with ENHERTU.
Heart problems that may affect your heart's ability to pump blood. Your healthcare provider will check your heart function before starting treatment with ENHERTU and during treatment if needed. Tell your healthcare provider right away if you get any of the following signs and symptoms: new or worsening shortness of breath coughing feeling tired swelling of your ankles or legs irregular heartbeat sudden weight gain dizziness or feeling light-headed loss of consciousness Your healthcare provider will check you for these side effects during your treatment with ENHERTU.
Your healthcare provider may reduce your dose, delay treatment or completely stop treatment with ENHERTU if you have severe side effects . Harm to your unborn baby. Tell your healthcare provider right away if you become pregnant or think you might be pregnant during treatment with ENHERTU.
If you are able to become pregnant, your healthcare provider should do a pregnancy test before you start treatment with ENHERTU. Females who are able to become pregnant should use effective birth control (contraception) during treatment with ENHERTU and for 7 months after the last dose. Males who have female partners that are able to become pregnant should use effective birth control (contraception) during treatment with ENHERTU and for 4 months after the last dose.
See " What are the possible side effects of ENHERTU? " for more information about side effects. What is ENHERTU? ENHERTU is a prescription medicine used to treat adults with: Human epidermal growth factor receptor 2 (HER2)-positive stage II or stage III early breast cancer followed by a taxane, trastuzumab and pertuzumab (THP) before surgery.
Your healthcare provider will perform a test to make sure ENHERTU is right for you. HER2-positive breast cancer that cannot be removed by surgery or has spread to other parts of the body (metastatic) in combination with pertuzumab as your first treatment. Your healthcare provider will perform a test to make sure ENHERTU in combination with pertuzumab is right for you.
ENHERTU alone is a prescription medicine used to treat adults with: HER2-positive early breast cancer who have received trastuzumab (with or without pertuzumab) and taxane-based treatment before surgery and have cancer remaining in the tissue removed during surgery. HER2-positive breast cancer that cannot be removed by surgery or that has spread to other parts of the body (metastatic), and who have received a prior anti-HER2 breast cancer treatment: for metastatic disease, or have breast cancer that has come back during or within 6 months of completing treatment for their early-stage breast cancer.
HER2-low breast cancer that cannot be removed by surgery or that has spread to other parts of the body (metastatic), and who have received a prior chemotherapy: for metastatic disease, or whose disease has returned during or within 6 months of… [Excerpted — this section continues on DailyMed.]
🧬 Pharmacokinetics ▾
12.3Pharmacokinetics The pharmacokinetics of fam-trastuzumab deruxtecan-nxki and its payload DXd were evaluated in patients with cancer and are presented as mean (% coefficient of variation), unless otherwise specified. At a dose of 5.4 mg/kg, the maximum concentration (C max ss ) of fam-trastuzumab deruxtecan-nxki is 132 µg/mL (20%) and of DXd is 4.7 ng/mL (48%) and the AUC ss of fam-trastuzumab deruxtecan-nxki is 772 µg∙day/mL (27%) and of DXd is 29 ng∙day/mL (48%). At a dose of 6.4 mg/kg, the C max,ss of fam-trastuzumab deruxtecan-nxki is 126 µg/mL (18%) and of DXd is 5.2 ng/mL (42%) and the AUC ss of fam-trastuzumab deruxtecan-nxki is 743 µg∙day/mL (26%) and of DXd is 33 ng∙day/mL (43%), respectively.
Following a single dose, C max and AUC of fam-trastuzumab deruxtecan-nxki and DXd increase in a dose proportional manner over a dose range of 3.2 mg/kg to 8 mg/kg (approximately 0.5 to 1.25 times the highest approved dose). Accumulation of fam-trastuzumab deruxtecan-nxki is approximately 1.4-fold at steady-state (Cycle 3). Distribution The estimated volume of distribution of the central compartment (Vc) of fam-trastuzumab deruxtecan-nxki is
2.7L (% CV 16%). DXd plasma protein binding is approximately 97% and the blood-to-plasma ratio is approximately 0.6 in vitro. Elimination The median elimination half-life of fam-trastuzumab deruxtecan-nxki is 5.4 to 5.7 days. The estimated systemic clearance of fam-trastuzumab deruxtecan-nxki is
0.4L/day (24%). The median elimination half-life of DXd is 5.4-6.1 days. The estimated systemic clearance of DXd is 18 L/h (28%).
Metabolism The monoclonal antibody is expected to be degraded into small peptides and amino acids via catabolic pathways. DXd is primarily metabolized by CYP3A4. Specific Populations No clinically significant differences in the pharmacokinetics of fam-trastuzumab deruxtecan-nxki or DXd were observed for age (20-96 years); race (Asian [48%] vs Non-Asian [52%]), including White (43%), and Black or African American (1.9%); sex; body weight (27-138 kg); tumor types; mild hepatic impairment; and mild or moderate renal impairment.
The pharmacokinetics of fam-trastuzumab deruxtecan-nxki or DXd in patients with moderate to severe hepatic impairment or severe renal impairment is unknown. Drug Interaction Studies Clinical Studies No clinically significant differences in pharmacokinetics of fam-trastuzumab deruxtecan-nxki or DXd were observed when used concomitantly with itraconazole (strong CYP3A inhibitor) or ritonavir (strong CYP3A inhibitor and OATP inhibitor). In Vitro Studies CYP450 Enzymes : DXd does not inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A nor induce CYP1A2, CYP2B6, or CYP3A.
UGT Enzymes: DXd is not a substrate of UGT. Transporter Systems : DXd is not an inhibitor of OAT1, OAT3, OCT1, OCT2, OATP1B1, OATP1B3, MATE1, MATE2-K, P-gp, BCRP, or BSEP. DXd is a substrate of OATP1B1, OATP1B3, MATE2-K, P-gp, MRP1, and BCRP.
🧬 Pharmacodynamics ▾
12.2Pharmacodynamics Exposure-Response Relationships Exposure-response relationship for efficacy has not been fully characterized. Higher systemic exposure to fam-trastuzumab deruxtecan-nxki was associated with a higher incidence rate of any grade ILD. Cardiac Electrophysiology At the dosage of ENHERTU 6.4 mg/kg every 3 weeks, a mean increase in the QTc interval >20 ms was not observed.
🔬 Clinical Studies ▾
14 CLINICAL STUDIES
14.1HER2-Positive Early Breast Cancer DESTINY-Breast11 The efficacy of ENHERTU followed by THP was evaluated in DESTINY-Breast11 (NCT05113251), a randomized, three-arm, open-label, multicenter, global study that enrolled 927 adult patients with HER2-positive, high-risk, early-stage breast cancer. The study included previously untreated adult patients with HER2-positive (IHC 3+ or ISH+), as determined by a central laboratory using PATHWAY anti-HER-2/neu (4B5) Rabbit Monoclonal Primary Antibody and VENTANA HER2 Dual ISH DNA Probe Cocktail assay, locally advanced high-risk (lymph node positive [N1-3] or with a primary tumor stage T3-4) or inflammatory early breast cancer.
Patients were excluded for a history of ILD/pneumonitis requiring treatment with steroids, ILD/pneumonitis at screening, or ECOG performance status >1. Patients were randomized 1:1:1 to receive eight cycles of neoadjuvant treatment with: ENHERTU (5.4 mg/kg once every 3 weeks) for 4 cycles followed by THP [paclitaxel (80 mg/m 2 once a week on Days 1, 8, and 15) concurrent with trastuzumab (6 mg/kg once every 3 weeks on Day 1) and pertuzumab (an initial dose of 840 mg followed by 420 mg once every 3 weeks on Day 1)] for 4 cycles. ddAC [doxorubicin (60 mg/m 2 once every 2 weeks) and cyclophosphamide (600 mg/m 2 once every 2 weeks)] for 4 cycles followed by THP [paclitaxel (80 mg/m2 once a week on Days 1, 8, and 15) concurrent with trastuzumab (an initial dose of 8 mg/kg followed by 6 mg/kg once every 3 weeks on Day 1) and pertuzumab (an initial dose of 840 mg followed by 420 mg once every 3 weeks on Day 1)] for 4 cycles.
An additional investigational therapy. Randomization was stratified by hormone receptor (HR) status (ER and/or PgR positive vs ER and PR negative) by local assessment and HER2-positive status (IHC 3+ vs other, where 'other' is defined as ISH+ in the absence of IHC 3+ status) by central assessment. Treatment was continued until completion of planned therapy, unacceptable toxicity, or disease progression.
The major efficacy outcome was centrally assessed pathological complete response (pCR) rate, defined as the absence of invasive cancer in the breast and axillary lymph nodes (ypT0/Tis ypN0) following surgery. In patients who received ENHERTU followed by THP or ddAC followed by THP, the median age was 50 years (range: 23 to 82), 11% age 65 or older; 100% female; 43% White, 49% Asian, 1.9% Black or African American, 0.3% American Indian or Alaska Native, 2% not reported; 9% Hispanic or Latino. Tumor characteristics were: 73% had HR+ status and 27% had HR− status; 57% had primary Tumor T0- T2 and 43% had T3-4; 89% had nodal involvement (N1+), 10% had no nodal involvement (N0); 51% of patients were overall Stage II and 49% were Stage III.
The study demonstrated a statistically significant improvement in pCR rate for patients randomized to ENHERTU followed by THP compared to ddAC followed by THP. Efficacy results are summarized in Table 26. At the time of the pCR analysis, 29 (4.5%) patients had EFS events and 12 (1.9%) patients had OS events.
Table 26: Efficacy Results in DESTINY-Breast11 Efficacy Parameter ENHERTU 5.4 mg/kg followed by THP (N=321) ddAC followed by THP (N=320) Pathological Complete Response (pCR) CI = confidence interval, THP = paclitaxel, trastuzumab, and pertuzumab, ddAC = dose dense doxorubicin and cyclophosphamide Number of patients with pCR, n 216 180 pCR rate, % (95% CI) 67.3 (61.9, 72.4) 56.3 (50.6, 61.8) Treatment difference estimate, % (95% CI) Based on Miettinen and Nurminen method stratified by HER2 status and HR status 11.2 (3.9, 18.3) p-value The 2-sided stratified Miettinen and Nurminen test p-value is compared with the allocated alpha of 0.03 0.003 DESTINY-Breast05 The efficacy of ENHERTU was evaluated in DESTINY-Breast05 (NCT04622319), a randomized, two-arm, open-label, multicenter, global study that enrolled 1635 adult patients with HER2-positive breast cancer with residual invasive disease after ne… [Excerpted — this section continues on DailyMed.]
🧪 Nonclinical Toxicology ▾
13 NONCLINICAL TOXICOLOGY
13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenicity studies have not been conducted with fam-trastuzumab deruxtecan-nxki. The topoisomerase inhibitor component of fam-trastuzumab deruxtecan-nxki, DXd, was clastogenic in both an in vivo rat bone marrow micronucleus assay and an in vitro Chinese hamster lung chromosome aberration assay and was not mutagenic in an in vitro bacterial reverse mutation assay. Fertility studies have not been conducted with fam-trastuzumab deruxtecan-nxki.
In a six-week repeat-dose toxicity study in rats, intravenous administration of fam-trastuzumab deruxtecan-nxki resulted in spermatid retention at 20 mg/kg and 60 mg/kg (approximately 4 and 9 times the human recommended dose of 5.4 mg/kg based on AUC, respectively). Decreased testes and epididymides weights, tubular atrophy/degeneration in testes, and reduced sperm count in epididymides were observed at a dose of 197 mg/kg (19 times the human recommended dose of 5.4 mg/kg based on AUC). In a three-month repeat-dose toxicity study in monkeys, intravenous administration of fam-trastuzumab deruxtecan-nxki resulted in decreased numbers of round spermatids in the testes at seminiferous tubule stages V to VI at ≥30 mg/kg (≥7 times the human recommended dose of 5.4 mg/kg based on AUC).
Evidence of reversibility was observed in monkeys by the end of a three-month recovery period.
📄 Carcinogenesis, Mutagenesis, Impairment of Fertility ▾
13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenicity studies have not been conducted with fam-trastuzumab deruxtecan-nxki. The topoisomerase inhibitor component of fam-trastuzumab deruxtecan-nxki, DXd, was clastogenic in both an in vivo rat bone marrow micronucleus assay and an in vitro Chinese hamster lung chromosome aberration assay and was not mutagenic in an in vitro bacterial reverse mutation assay. Fertility studies have not been conducted with fam-trastuzumab deruxtecan-nxki.
In a six-week repeat-dose toxicity study in rats, intravenous administration of fam-trastuzumab deruxtecan-nxki resulted in spermatid retention at 20 mg/kg and 60 mg/kg (approximately 4 and 9 times the human recommended dose of 5.4 mg/kg based on AUC, respectively). Decreased testes and epididymides weights, tubular atrophy/degeneration in testes, and reduced sperm count in epididymides were observed at a dose of 197 mg/kg (19 times the human recommended dose of 5.4 mg/kg based on AUC). In a three-month repeat-dose toxicity study in monkeys, intravenous administration of fam-trastuzumab deruxtecan-nxki resulted in decreased numbers of round spermatids in the testes at seminiferous tubule stages V to VI at ≥30 mg/kg (≥7 times the human recommended dose of 5.4 mg/kg based on AUC).
Evidence of reversibility was observed in monkeys by the end of a three-month recovery period.
📚 References ▾
15 REFERENCES OSHA Hazardous Drugs. OSHA . http://www.osha.gov/SLTC/hazardousdrugs/index.html
📄 Recent Major Changes ▾
Indications and Usage ( 1.1 ) 05/2026 Indications and Usage ( 1.2 ) 12/2025 Dosage and Administration ( 2.1 , 2.2 , 2.3 ) 05/2026 Dosage and Administration ( 2.1 , 2.2 , 2.3 ) 12/2025 Warnings and Precautions ( 5.1 , 5.2 , 5.3 ) 05/2026 Warnings and Precautions ( 5.1 , 5.2 , 5.3 ) 12/2025
📄 Package Label / Principal Display Panel ▾
PRINCIPAL DISPLAY PANEL - 100 mg Vial Carton NDC 65597-406-01 Rx only ENHERTU ® (fam-trastuzumab deruxtecan-nxki) For Injection 100 mg per vial For Intravenous Infusion Only Dispense the enclosed Medication Guide to each patient. Reconstitute and Dilute prior to administration Single-Dose Vial Discard Unused Portion Hazardous Drug KEEP REFRIGERATED 1 vial Daiichi-Sankyo AstraZeneca PRINCIPAL DISPLAY PANEL - 100 mg Vial Carton
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