Fam-trastuzumab deruxtecan-nxki Injection
Fam-trastuzumab deruxtecan-nxki is an antibody-drug conjugate used to treat several HER2-positive, HER2-low, and HER2-ultralow cancers, including breast cancer, non-small cell lung cancer, gastric cancer, and other HER2-positive solid tumors.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾
Enhertu carries two serious boxed warnings that every patient should know about.
First, it can cause interstitial lung disease (ILD) — inflammation of the lungs — that can be severe, life-threatening, or fatal. Watch for any new cough, shortness of breath, fever, or other breathing changes and report them to your doctor right away. If symptomatic lung inflammation is confirmed, Enhertu must be permanently discontinued.
Second, Enhertu can seriously harm or kill an unborn baby (embryo-fetal toxicity). Women of childbearing potential must use effective birth control during treatment and for 7 months after the last dose. Men should use contraception for 4 months after their last dose. Tell your doctor immediately if you become pregnant during treatment.
📖 Fam-trastuzumab deruxtecan-nxki Injection: Patient Information Guide
A plain-language walkthrough of Fam-trastuzumab deruxtecan-nxki Injection — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Enhertu (fam-trastuzumab deruxtecan-nxki) is approved for multiple HER2-related cancers in adults. The specific use depends on HER2 status confirmed by an FDA-authorized test.
- HER2-positive early breast cancer (neoadjuvant): Enhertu is given before surgery for Stage II or III HER2-positive breast cancer, followed by a taxane, trastuzumab, and pertuzumab (THP) regimen.
- HER2-positive early breast cancer (adjuvant): Enhertu is given after surgery when cancer remains following neoadjuvant trastuzumab-based treatment.
- HER2-positive metastatic breast cancer (first-line, with pertuzumab): Enhertu in combination with pertuzumab for unresectable or metastatic HER2-positive breast cancer.
- HER2-positive metastatic breast cancer (monotherapy): Enhertu alone for patients who have already received a prior anti-HER2 regimen.
- HER2-low or HER2-ultralow metastatic breast cancer: Enhertu for hormone receptor-positive, HER2-low or HER2-ultralow breast cancer that has progressed on endocrine therapy, or HER2-low breast cancer after prior chemotherapy.
- HER2-mutant non-small cell lung cancer (NSCLC): Enhertu for unresectable or metastatic NSCLC with activating HER2 mutations after prior systemic therapy (accelerated approval).
- HER2-positive gastric or gastroesophageal junction cancer: Enhertu for locally advanced or metastatic HER2-positive gastric or GEJ adenocarcinoma after prior trastuzumab-based treatment.
- HER2-positive (IHC 3+) solid tumors: Enhertu for unresectable or metastatic HER2-positive solid tumors after prior systemic treatment with no satisfactory alternatives (accelerated approval).
⚙️How it works▾
Enhertu is an antibody-drug conjugate — a cancer-targeting molecule with two working parts. The antibody portion homes in on HER2, a protein found in high amounts on the surface of certain cancer cells. Once it locks onto HER2, the whole complex is pulled inside the cancer cell. There, enzymes inside the cell cut a chemical linker and release a potent chemotherapy agent called DXd (a topoisomerase I inhibitor). DXd disrupts how cancer cells copy their DNA, leading to DNA damage and cell death. Because DXd can pass through cell membranes, it may also affect neighboring tumor cells that express lower levels of HER2.
💊How it's taken▾
Enhertu is given as an intravenous (IV) infusion, typically once every 3 weeks. The exact number of treatment cycles varies by indication — for example, it may be given for a set number of cycles in the neoadjuvant (pre-surgery) setting, or continued until disease progression or unacceptable side effects in the metastatic setting. For HER2-positive metastatic breast cancer, Enhertu may be given alongside pertuzumab, which is infused separately after Enhertu on the same day. For HER2-positive gastric cancer, a different dose level is used compared to breast cancer and lung cancer.
- Anti-nausea medications are given before every infusion.
- If you miss or delay a scheduled dose, your care team will reschedule it and maintain the 3-week interval.
- The dose may be reduced or paused if side effects occur — do not restart or adjust doses on your own.
🤒Side effects — in detail▾
Enhertu commonly causes a range of side effects that your care team will monitor closely throughout treatment.
- Nausea and vomiting (very common; anti-nausea drugs are given to help)
- Low white blood cell counts (neutropenia), increasing infection risk
- Low red blood cell counts (anemia), causing fatigue
- Low platelet counts, which can increase bleeding risk
- Fatigue and general weakness
- Hair loss
- Diarrhea or constipation
- Decreased appetite
- Elevated liver enzymes on blood tests
- Musculoskeletal pain
Serious reactions requiring immediate medical attention include lung inflammation (ILD/pneumonitis), severe drops in white blood cells (febrile neutropenia), reduced heart pumping function (left ventricular dysfunction), and infusion reactions. Report any new breathing symptoms, fever, chest discomfort, or signs of infection to your doctor right away.
⚠️Warnings & precautions▾
- Lung inflammation (ILD/pneumonitis): This is the most critical risk. Cases have been severe, life-threatening, and fatal. Any new or worsening cough, shortness of breath, or fever must be reported immediately. Enhertu must be permanently stopped if symptomatic (Grade 2 or higher) ILD is confirmed. Patients with moderate kidney impairment have a higher risk.
- Embryo-fetal toxicity: Enhertu can cause serious harm or death to a developing baby. Reliable contraception is required during and after treatment — 7 months for women, 4 months for men. Pregnancy testing is done before starting treatment.
- Low white blood cell counts (neutropenia): Blood counts are checked before every dose. Severe neutropenia can lead to dangerous infections. Dose pauses or reductions may be needed.
- Heart function (left ventricular dysfunction): Enhertu can reduce the heart's ability to pump. Heart function (LVEF) is assessed before and during treatment. Symptomatic heart failure requires permanent discontinuation.
- Do not substitute: Enhertu must never be substituted for trastuzumab or ado-trastuzumab emtansine — these are different medications with different doses and uses.
🔀What it interacts with▾
Based on clinical studies, there are limited drug interactions identified for Enhertu, but always tell your entire care team about every medication, supplement, or herbal product you take.
- Strong CYP3A inhibitors (e.g., itraconazole, ritonavir): Clinical studies showed no clinically significant change in Enhertu or DXd exposure, but your oncologist should be aware of all medications you are taking.
- Other cancer therapies: Enhertu is used in combination with pertuzumab for certain indications — this combination has its own monitoring requirements; refer to your care team for details on pertuzumab dose adjustments.
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- Pregnancy: Enhertu can cause serious fetal harm, including death. Tell your doctor immediately if you are pregnant or become pregnant during treatment.
- Breastfeeding: Do not breastfeed during Enhertu treatment or for 7 months after the last dose due to risk of serious harm to the baby.
- Contraception (women): Use effective birth control during treatment and for 7 months after the last dose.
- Contraception (men): Men with female partners of childbearing potential should use contraception during treatment and for 4 months after the last dose. Enhertu may also impair male fertility.
- Heart disease: Enhertu has not been studied in patients with significant cardiac disease or baseline LVEF below 50% — discuss your heart history with your oncologist.
- Liver impairment: Patients with moderate liver impairment need close monitoring for increased DXd-related side effects. Dosing is not established for severe liver impairment.
- Kidney impairment: No dose adjustment is needed for mild or moderate kidney impairment, but patients with moderate impairment have a higher rate of lung inflammation and should be monitored carefully.
- Children: Safety and effectiveness in pediatric patients have not been established.
- Older adults: Patients aged 65 and older may experience higher rates of serious (Grade 3–4) side effects and should be monitored closely.
📡Pharmacodynamics — effects in the body▾
Higher blood levels (systemic exposure) of Enhertu are associated with a higher rate of lung inflammation (ILD/pneumonitis) of any severity, meaning the risk of this side effect increases with greater exposure to the drug. At the 6.4 mg/kg dose, Enhertu did not cause a clinically meaningful change in the heart's electrical rhythm (QTc interval prolongation was not observed above 20 milliseconds). The full relationship between drug exposure and treatment effectiveness has not been completely characterized.
🔬Pharmacokinetics — how your body processes it▾
After intravenous infusion, Enhertu distributes into a relatively small volume in the body. The drug reaches steady-state levels by approximately the third treatment cycle, with about 1.4-fold accumulation. The antibody component of Enhertu has a median elimination half-life of about 5.4 to 5.7 days, meaning it takes roughly that time for half of the drug to leave the body. The released chemotherapy payload DXd has a similar half-life and is broken down mainly by the liver enzyme CYP3A4. The body's handling of Enhertu and DXd is not meaningfully affected by age, sex, body weight, race, or mild kidney or liver problems.
📦How to store it▾
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.
📄 Written from Fam-trastuzumab deruxtecan-nxki Injection’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
Supplements & herbs that interact with Fam-trastuzumab deruxtecan-nxki Injection
37 supplements and herbal products have documented interactions with Fam-trastuzumab deruxtecan-nxki Injection in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 1
- Moderate · 28
- Minor · 8
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Fam-trastuzumab deruxtecan-nxki Injection — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly is Enhertu and how is it different from regular chemotherapy? ▾
How will I receive Enhertu, and how often do I need to come in? ▾
What side effects should I expect, and which ones should make me call my doctor right away? ▾
I'm a woman of childbearing age. Do I need to worry about pregnancy while on Enhertu? ▾
My doctor mentioned lung inflammation as a risk. How common is it, and what should I do if I think it's happening? ▾
Can I take my other medications while on Enhertu? ▾
Is Fam-trastuzumab deruxtecan-nxki Injection available over the counter? ▾
When was Fam-trastuzumab deruxtecan-nxki Injection first available? ▾
Who makes Fam-trastuzumab deruxtecan-nxki Injection? ▾
💬 Answers drafted from Fam-trastuzumab deruxtecan-nxki Injection’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
💊 How Fam-trastuzumab deruxtecan-nxki Injection comes
Fam-trastuzumab deruxtecan-nxki Injection is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Injection
How this form is used
- Enhertu is used intravenously for HER2-positive early breast cancer (neoadjuvant before surgery or adjuvant after surgery with residual disease)
- Enhertu is used intravenously for unresectable or metastatic HER2-positive, HER2-low, or HER2-ultralow breast cancer
- Enhertu is used intravenously for HER2-mutant unresectable or metastatic non-small cell lung cancer and HER2-positive locally advanced or metastatic gastric or gastroesophageal junction cancer
- Enhertu is used intravenously for unresectable or metastatic HER2-positive (IHC 3+) solid tumors with no satisfactory alternative treatment options
- Enhertu is given as an intravenous infusion only — never as an IV push or bolus injection
- Enhertu must not be substituted for trastuzumab or ado-trastuzumab emtansine; check the vial label carefully before each dose
- Enhertu must not be mixed with Sodium Chloride Injection; follow your care team's preparation instructions
- Anti-nausea (antiemetic) medications are given before each Enhertu infusion to help prevent nausea and vomiting
📊 Fam-trastuzumab deruxtecan-nxki Injection across the U.S. market
How Fam-trastuzumab deruxtecan-nxki Injection appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
📈 How widely Fam-trastuzumab deruxtecan-nxki Injection is used
A general measure of how commonly Fam-trastuzumab deruxtecan-nxki Injection is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Fam-trastuzumab deruxtecan-nxki Injection is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Fam-trastuzumab deruxtecan-nxki Injection prescribed? Of the 1,594 medications we measure, Fam-trastuzumab deruxtecan-nxki Injection ranks #824 by Medicaid prescriptions — more than 48% of them.
Utilization by Fam-trastuzumab deruxtecan-nxki Injection product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
Other Fam-trastuzumab deruxtecan-nxki Injection products — combination packs and listings not yet matched to a specific clinical product (kept visible so every prescription is accounted for)
Summed across the 1 of 1 listed NDC products with Medicaid activity.
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Fam-trastuzumab deruxtecan-nxki Injection, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 1 of 1 listed Fam-trastuzumab deruxtecan-nxki Injection NDCs with Medicaid activity.
🔍 Compare Fam-trastuzumab deruxtecan-nxki Injection products
A representative set of FDA-listed product records for Fam-trastuzumab deruxtecan-nxki Injection — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Injection | ||||
| 100 mg/5 mL | Intravenous | Daiichi Sankyo, Inc. × 2 listings | BLA | View NDC → |
| 100 mg/5 mL | Intravenous | Daiichi Sankyo Inc. | BLA | View NDC → |
Showing 3 of 3 products — FDA National Drug Code Directory. See every product, package size and price: browse all 3 Fam-trastuzumab deruxtecan-nxki Injection NDCs →
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Fam-trastuzumab deruxtecan-nxki Injection — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Fam-trastuzumab deruxtecan-nxki Injection in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How Fam-trastuzumab deruxtecan-nxki Injection went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
📦 Supply & shortage status
Whether Fam-trastuzumab deruxtecan-nxki Injection is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
Fam-trastuzumab deruxtecan-nxki Injection belongs to the HER2/neu Receptor Antagonist class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 1 FDA-filed SPL label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Daiichi Sankyo, Inc. is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.