Trastuzumab and Hyaluronidase-oysk Injection
Trastuzumab and hyaluronidase-oysk is a HER2-targeted cancer medicine given as an injection under the skin. It treats HER2-positive breast cancer, both early-stage (adjuvant) and metastatic.
🧬 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 →
Herceptin Hylecta is trastuzumab, a cornerstone of early and metastatic HER2-positive breast cancer treatment that blocks the HER2 protein to slow tumor growth and help the immune system attack, plus hyaluronidase, an enzyme that lets it go under the skin in minutes instead of by IV; on the market since about 2019, it is not available as a generic. Most people handle it fairly well, mostly noticing tiredness, achy joints or muscles and injection-site reactions. Its boxed warning covers heart damage, serious lung and allergic reactions, and harm to an unborn baby, so keep every heart check and report breathlessness, ankle swelling or a pregnancy right away.
Clinical pearls
- It is not interchangeable with IV trastuzumab or Kadcyla (ado-trastuzumab emtansine), so confirm the exact product name before each dose.
- For 7 months after stopping, remind any prescriber considering doxorubicin or another anthracycline, because the heart risk adds up.
- Expect heart pumping checks (LVEF) about every 3 months, then every 6 months for at least 2 years after early-stage treatment.
- Use effective birth control during treatment and for 7 months after the last dose; it can dangerously lower amniotic fluid.
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾
This medicine can cause serious heart problems, lung problems and harm to an unborn baby.
- Heart: It can weaken the heart and cause heart failure, with or without symptoms. The risk is highest when it is combined with anthracycline chemotherapy. Your heart function is checked before and during treatment, and treatment may be stopped or paused.
- Lungs and allergic reactions: Serious and sometimes fatal lung problems can occur, usually during or within 24 hours of the injection. Treatment is stopped for anaphylaxis, swelling of the face or throat (angioedema), lung inflammation (interstitial pneumonitis) or acute respiratory distress syndrome.
- Pregnancy: It can cause low amniotic fluid (oligohydramnios). This can lead to underdeveloped lungs, bone problems and death in newborns. Effective birth control is needed.
Patient information guide A plain-language walkthrough of Trastuzumab and Hyaluronidase-oysk Injection, written from its FDA label.
What Trastuzumab and Hyaluronidase-oysk Injection is used for
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Herceptin Hylecta is used in adults for HER2-overexpressing breast cancer:
- Adjuvant (after surgery) treatment of node-positive or node-negative breast cancer, as part of a regimen with doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel.
- Adjuvant treatment as part of a regimen with docetaxel and carboplatin.
- Adjuvant treatment as a single agent after multi-modality anthracycline-based therapy.
- First-line treatment of metastatic breast cancer in combination with paclitaxel.
- Treatment of metastatic breast cancer as a single agent in patients who have had one or more chemotherapy regimens for metastatic disease.
Patients are selected using an FDA-authorized HER2 test.
How Trastuzumab and Hyaluronidase-oysk Injection works
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Trastuzumab binds to HER2, a protein on the surface of some breast cancer cells. This slows the growth of cells that have too much HER2. It also helps immune cells attack those cancer cells, and works more on HER2-heavy cells than on others.
Hyaluronidase temporarily breaks down hyaluronan, a substance in tissue under the skin. This helps the trastuzumab be absorbed. Its effect is local and wears off within 24 to 48 hours.
Trastuzumab and Hyaluronidase-oysk Injection dosage
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Herceptin Hylecta is given only under the skin, never into a vein. A healthcare professional injects it into the thigh over about 2 to 5 minutes, once every three weeks. No loading dose is needed, and the dose is not adjusted for body weight.
- Adjuvant treatment lasts 52 weeks or until the cancer returns, whichever comes first.
- Metastatic treatment continues until the cancer progresses.
- If a dose is missed, it should be given as soon as possible. Doses should be at least three weeks apart.
Dosing details from the FDA-approved label
From the Trastuzumab and Hyaluronidase-oysk Injection prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Adjuvant breast cancer
- 600 mg/10,000 units (600 mg trastuzumab and 10,000 units hyaluronidase) administered subcutaneously over approximately 2-5 minutes once every three weeks
- Treat for 52 weeks or until disease recurrence, whichever occurs first
- No loading dose is required. No dose adjustments for patient body weight or for different concomitant chemotherapy regimens are required. Extending treatment beyond one year is not recommended.
- Metastatic breast cancer (MBC)
- 600 mg/10,000 units (600 mg trastuzumab and 10,000 units hyaluronidase) administered subcutaneously over approximately 2-5 minutes once every three weeks
- Treat until progression of disease
- No loading dose is required. No dose adjustments for patient body weight or for different concomitant chemotherapy regimens are required.
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION For subcutaneous use only. HERCEPTIN HYLECTA has different dosage and administration instructions than intravenous trastuzumab products. Do not administer intravenously. ( 2.3 ) Do not substitute HERCEPTIN HYLECTA for or with ado-trastuzumab emtansine. ( 2.3 ) Perform HER2 testing using FDA-authorized tests by laboratories with demonstrated proficiency. ( 1 , 2.2 ) The recommended dose of HERCEPTIN HYLECTA is 600 mg/10,000 units (600 mg trastuzumab and 10,000 units hyaluronidase) administered subcutaneously over approximately 2-5 minutes once every three weeks. ( 2.3 ) 2.1 Evaluation and Testing Before Initiating HERCEPTIN HYLECTA Verify the pregnancy status of females of reproductive potential prior to the initiation of HERCEPTIN HYLECTA [see Use in Specific Populations (8.1 , 8.3) ] . 2.2 Patient Selection Select patients based on HER2 protein overexpression or HER2 gene amplification in tumor specimens [see Indications and Usage (1) and Clinical Studies (14) ] . Assessment of HER2 protein overexpression and HER2 gene amplification should be performed using FDA-authorized tests specific for breast cancer by laboratories with demonstrated proficiency. Information on the FDA-authorized tests for the detection of HER2 protein overexpression and HER2 gene amplification is available at: http://www.fda.gov/CompanionDiagnostics. Improper assay performance, including use of suboptimally fixed tissue, failure to utilize specified reagents, deviation from specific assay instructions, and failure to include appropriate controls for assay validation, can lead to unreliable results. 2.3 Recommended Dosage HERCEPTIN HYLECTA is for subcutaneous use only. HERCEPTIN HYLECTA has different dosage and administration instructions than intravenous trastuzumab products. Do not administer intravenously. Do not substitute HERCEPTIN HYLECTA for or with ado-trastuzumab emtansine. The recommended dose of HERCEPTIN HYLECTA is 600 mg/10,000 units (600 mg trastuzumab and 10,000 units hyaluronidase) administered subcutaneously over approximately 2-5 minutes once every three weeks. No loading dose is required. No dose adjustments for patient body weight or for different concomitant chemotherapy regimens are required.
Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →
Trastuzumab and Hyaluronidase-oysk Injection side effects
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Common side effects in studies included:
Common side effects
- Tiredness
- Joint and muscle pain
- Diarrhea and nausea
- Injection site reactions
- Rash
- Headache
- Fever
- Cough
- Cough and upper respiratory infections
- Pain in the arms or legs
When to get medical help
- Call your doctor right away for shortness of breath, swelling in your legs or ankles, a racing or irregular heartbeat, or sudden weight gain. These can be signs of heart problems.
- Get emergency help for signs of a severe allergic reaction, such as trouble breathing, swelling of the face or throat, or hives. This is most likely during or within 24 hours of the injection.
- Report new cough, trouble breathing or breathlessness, which can signal lung problems.
- Tell your doctor about fever or signs of infection, since the medicine can worsen low white blood cell counts caused by chemotherapy.
- Tell your doctor right away if you become pregnant during treatment or within 7 months after your last dose.
Trastuzumab and Hyaluronidase-oysk Injection warnings and precautions
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- Heart damage: It can cause heart failure and a drop in heart function, most often with anthracycline chemotherapy. Heart function is checked before, during and after treatment.
- Lung problems and severe allergic reactions: These can be serious or fatal, usually during or within 24 hours of the injection.
- Harm to an unborn baby: Low amniotic fluid can lead to lung and bone problems and newborn death.
- Low white blood cells: It can make chemotherapy-related neutropenia worse.
Trastuzumab and Hyaluronidase-oysk Injection interactions
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The main interaction is with anthracycline chemotherapy.
- Anthracyclines (such as doxorubicin): together they raise the risk of heart problems.
- Anthracyclines after stopping: the drug stays in the body a long time, so avoid them for up to 7 months if possible. If they are used, your heart should be closely monitored.
- Ado-trastuzumab emtansine and intravenous trastuzumab: these are different products and must not be substituted for each other.
Interactions listed in the FDA-approved label
From the Trastuzumab and Hyaluronidase-oysk Injection prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.
- Anthracyclines: Patients who receive anthracycline after stopping HERCEPTIN HYLECTA may be at increased risk of cardiac dysfunction because of its estimated long washout period. If possible, avoid anthracycline-based therapy for up to 7 months after stopping HERCEPTIN HYLECTA. If anthracyclines are used, closely monitor the patient's cardiac function.
Read the label’s full interactions text
7 DRUG INTERACTIONS Anthracyclines Patients who receive anthracycline after stopping HERCEPTIN HYLECTA may be at increased risk of cardiac dysfunction because of HERCEPTIN HYLECTA's estimated long washout period [see Clinical Pharmacology (12.3) ] . If possible, avoid anthracycline-based therapy for up to 7 months after stopping HERCEPTIN HYLECTA. If anthracyclines are used, closely monitor the patient's cardiac function.
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking Trastuzumab and Hyaluronidase-oysk Injection
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- There are no listed contraindications.
- Tell your doctor about any heart problems.
- Pregnancy status is verified before starting. Use effective contraception during treatment and for 7 months after the last dose.
- If you become pregnant during treatment or within 7 months after, report it right away.
- Discuss breastfeeding with your doctor. The drug stays in the body for about 7 months.
- It has not been established as safe or effective in children.
- Older adults may have a higher risk of heart problems.
What Trastuzumab and Hyaluronidase-oysk Injection does in the body
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In patients with HER2-positive solid tumors, trastuzumab had no clinically relevant effect on the QTc interval, a measure of the heart's electrical rhythm on an ECG.
How your body processes Trastuzumab and Hyaluronidase-oysk Injection
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After an injection under the skin, trastuzumab levels peak at about 3 days. About 77% of the dose is absorbed into the bloodstream. Levels are roughly stable after the seventh dose. The drug leaves the body slowly. Levels are expected to drop below 1 mcg/mL by about 7 months after stopping in most patients, which is why precautions last 7 months. No dose changes are needed for body weight.
How to store Trastuzumab and Hyaluronidase-oysk Injection
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Store HERCEPTIN HYLECTA vials in the refrigerator at 2°C to 8°C (36°F to 46°F) in the original carton to protect from light. Do not freeze. refrigerator, HERCEPTIN HYLECTA must be administered within 4 hours and should not be kept above 30°C (86°F).
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Trastuzumab and Hyaluronidase-oysk Injection: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Trastuzumab and Hyaluronidase-oysk Injection — the kind of thing our pharmacy team would talk through with you at the counter.
What is this medicine for?
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How is it given?
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What side effects should I expect?
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When should I call my doctor?
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Why does it affect my heart?
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Is it safe in pregnancy?
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Is Trastuzumab and Hyaluronidase-oysk Injection available over the counter?
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When was Trastuzumab and Hyaluronidase-oysk Injection first available?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Trastuzumab and Hyaluronidase-oysk Injection on HelloPharmacist
Trastuzumab and Hyaluronidase-oysk Injection forms and strengths (how it comes)
Trastuzumab and Hyaluronidase-oysk 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.
Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Trastuzumab and Hyaluronidase-oysk Injection inactive ingredients by manufacturer.
Injection
How this form is used
- Herceptin Hylecta is used in adults for adjuvant treatment of HER2-overexpressing breast cancer.
- Herceptin Hylecta is used in adults for HER2-overexpressing metastatic breast cancer.
- Herceptin Hylecta is for subcutaneous use only and must not be given into a vein.
- Herceptin Hylecta is given by a healthcare professional into the thigh, alternating between the left and right thigh.
- Herceptin Hylecta is given over about 2 to 5 minutes once every three weeks, with no loading dose.
- Herceptin Hylecta is not interchangeable with ado-trastuzumab emtansine or intravenous trastuzumab products.
Trastuzumab and Hyaluronidase-oysk Injection on the U.S. market: products, makers and brands
How Trastuzumab and Hyaluronidase-oysk 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.
1 company lists 1 Trastuzumab and Hyaluronidase-oysk Injection product record with the FDA, mostly as injection; the earliest marketing or approval year on record is 2019. Brand names on the directory include Herceptin Hylecta; the rest are generics.
How widely Trastuzumab and Hyaluronidase-oysk Injection is used (Medicaid data)
A general measure of how commonly Trastuzumab and Hyaluronidase-oysk 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 Trastuzumab and Hyaluronidase-oysk 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 Trastuzumab and Hyaluronidase-oysk Injection prescribed? Of the 1,601 medications we measure, Trastuzumab and Hyaluronidase-oysk Injection ranks #1,399 by Medicaid prescriptions — more than 13% of them.
Utilization by Trastuzumab and Hyaluronidase-oysk 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.
5 ML hyaluronidase-oysk 2000 UNT/ML / trastuzumab-oysk 120 MG/ML Injection
Summed across the 1 of 1 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2119714
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 Trastuzumab and Hyaluronidase-oysk 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 Trastuzumab and Hyaluronidase-oysk Injection NDCs with Medicaid activity.
Compare Trastuzumab and Hyaluronidase-oysk Injection products
A representative set of FDA-listed product records for Trastuzumab and Hyaluronidase-oysk 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 | ||||
| TRASTUZUMAB 600 mg/5 mL; HYALURONIDASE (HUMAN RECOMBINANT) 10000 U/5 mL | Subcutaneous | Genentech, Inc. | BLA | View NDC → |
Showing 1 of 1 products — FDA National Drug Code Directory. See every product, package size and price: browse all 1 Trastuzumab and Hyaluronidase-oysk Injection NDCs →
Trastuzumab and Hyaluronidase-oysk Injection side effects reported to the 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 Trastuzumab and Hyaluronidase-oysk 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 Trastuzumab and Hyaluronidase-oysk 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.
Trastuzumab and Hyaluronidase-oysk Injection FDA approval history
How Trastuzumab and Hyaluronidase-oysk Injection went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Trastuzumab and Hyaluronidase-oysk Injection 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.
The FDA’s enforcement reports list no Trastuzumab and Hyaluronidase-oysk recalls since July 2021.
✅No Trastuzumab and Hyaluronidase-oysk recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
Trastuzumab and Hyaluronidase-oysk Injection supply and shortage status
Whether Trastuzumab and Hyaluronidase-oysk 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.
Trastuzumab and Hyaluronidase-oysk Injection brand names
Trastuzumab and Hyaluronidase-oysk Injection is sold under one brand name in the FDA directory — Herceptin Hylecta. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Trastuzumab and Hyaluronidase-oysk Injection: manufacturers and labelers
One company lists Trastuzumab and Hyaluronidase-oysk Injection products with the FDA. By number of product records, the largest are Genentech, Inc.. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
Trastuzumab and Hyaluronidase-oysk Injection drug class (RxNorm)
Trastuzumab and Hyaluronidase-oysk 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.
Sources for this Trastuzumab and Hyaluronidase-oysk Injection page
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 this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Genentech, Inc. is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →