Trastuzumab and Hyaluronidase-oysk Injection
Trastuzumab and hyaluronidase-oysk is a combination injectable medicine used to treat HER2-overexpressing breast cancer in adults, both in early-stage (adjuvant) and metastatic (spread) settings.
🧬 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 ▾
Herceptin Hylecta carries three serious boxed warnings — the FDA's most urgent safety alerts:
Heart damage (Cardiomyopathy): This medicine can cause the heart to weaken, sometimes severely, leading to heart failure. The risk is greatest when it is given alongside anthracycline chemotherapy drugs. Heart function must be checked before and regularly during treatment. If significant heart weakening occurs, the medicine must be stopped.
Harm to an unborn baby (Embryo-Fetal Toxicity): Taking Herceptin Hylecta during pregnancy can cause very low amniotic fluid (oligohydramnios), which may lead to lung underdevelopment, bone problems, and in some cases the death of the newborn. Women who can become pregnant must use effective birth control during treatment and for 7 months after the last dose.
Serious lung reactions (Pulmonary Toxicity): Herceptin Hylecta can cause life-threatening lung problems, including severe allergic reactions (anaphylaxis), lung inflammation (interstitial pneumonitis), and acute respiratory distress syndrome. If any of these occur, the medicine must be permanently stopped.
📖 Trastuzumab and Hyaluronidase-oysk Injection: Patient Information Guide
A plain-language walkthrough of Trastuzumab and Hyaluronidase-oysk 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▾
Trastuzumab and hyaluronidase-oysk is a targeted cancer medicine approved for adults with HER2-overexpressing breast cancer, confirmed by an FDA-authorized diagnostic test. All uses below are for Herceptin Hylecta, the subcutaneous injection form.
- Adjuvant breast cancer (early-stage, after surgery): Herceptin Hylecta treats HER2-overexpressing node-positive or certain node-negative breast cancer as part of regimens including doxorubicin, cyclophosphamide, and paclitaxel or docetaxel; or with docetaxel and carboplatin; or as a single agent following multi-modality anthracycline-based therapy
- Metastatic breast cancer (first-line): Herceptin Hylecta is used in combination with paclitaxel as an initial treatment when HER2-overexpressing breast cancer has spread
- Metastatic breast cancer (later lines): Herceptin Hylecta is used as a single agent in adults who have already received one or more chemotherapy regimens for metastatic disease
⚙️How it works▾
HER2 is a protein receptor found in excessive amounts on the surface of certain breast cancer cells, where it acts like a stuck accelerator — constantly telling cells to grow and divide. Trastuzumab is an antibody that locks onto the HER2 receptor, helping to slow or stop that growth signal. It also helps the immune system recognize and attack those cancer cells through a process called ADCC (antibody-dependent cellular cytotoxicity). Hyaluronidase-oysk temporarily breaks down a substance in the tissue under the skin, creating a pathway for trastuzumab to absorb rapidly into the bloodstream — allowing the whole dose to be delivered in just a few minutes via a short under-the-skin injection rather than a lengthy IV infusion.
💊How it's taken▾
Herceptin Hylecta is given as a subcutaneous injection (under the skin of the thigh) by a healthcare professional once every three weeks. The injection takes approximately 2 to 5 minutes. No loading dose is required, and no dose adjustment for body weight or concurrent chemotherapy regimen is needed.
- For adjuvant breast cancer, treatment continues for 52 weeks (about one year) or until cancer returns — whichever comes first; extending beyond one year is not recommended
- For metastatic breast cancer, treatment continues until the cancer progresses
- If a dose is missed, it should be given as soon as possible; the following dose should not be given less than 3 weeks after that catch-up dose
🤒Side effects — in detail▾
The most commonly reported side effects with Herceptin Hylecta include:
- Hair loss (alopecia)
- Nausea, diarrhea, or vomiting
- Fatigue or weakness (asthenia)
- Administration-related reactions (ARRs) such as rash, flushing, itching, or cough
- Low white blood cell counts (neutropenia), which raise infection risk
- Injection site reactions — pain or redness where the shot was given
- Muscle aches (myalgia) and joint pain (arthralgia)
- Headache and peripheral nerve tingling or numbness
Seek immediate medical attention for signs of heart problems (shortness of breath, rapid heartbeat, swelling), severe allergic reactions (anaphylaxis), or new breathing difficulties — these are serious reactions that may require stopping the medicine.
⚠️Warnings & precautions▾
- Heart damage (cardiomyopathy): Herceptin Hylecta can weaken the heart's pumping function, sometimes causing heart failure. Risk is highest when combined with anthracycline chemotherapy. Heart function (LVEF) is measured before treatment, every 3 months during treatment, and for at least 2 years after completing adjuvant therapy. The medicine may be paused or permanently stopped if significant heart weakening occurs.
- Serious harm to an unborn baby: Using Herceptin Hylecta during pregnancy can cause very low amniotic fluid (oligohydramnios), underdeveloped lungs, bone abnormalities, and neonatal death. Effective contraception is required during treatment and for 7 months after the last dose. Pregnancy should be reported immediately to your doctor and to Genentech.
- Serious lung and allergic reactions: Life-threatening reactions including anaphylaxis, severe swelling (angioedema), lung inflammation (interstitial pneumonitis), and acute respiratory distress syndrome have occurred — sometimes within 24 hours of a dose. These require permanent discontinuation of the medicine.
- Worsening of chemotherapy-related low white blood cell counts (neutropenia): Herceptin Hylecta can make chemotherapy-induced neutropenia worse, raising the risk of serious infection.
- Hypersensitivity and injection reactions: Severe reactions have been reported; patients are monitored during and after each dose. Permanent discontinuation is required for anaphylaxis or severe hypersensitivity.
🔀What it interacts with▾
There are limited formal drug interaction studies with trastuzumab, but one clinically important interaction is known:
- Anthracycline chemotherapy (e.g., doxorubicin, epirubicin): Receiving these drugs after stopping Herceptin Hylecta significantly increases the risk of heart damage. This is because trastuzumab stays in the body for a long time (estimated washout period of about 7 months). If anthracyclines must be used, avoid them for up to 7 months after the last Herceptin Hylecta dose and monitor heart function closely.
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▾
- Heart history: Tell your doctor about any prior heart problems, high blood pressure, or arrhythmia — Herceptin Hylecta requires a heart function check before starting and regular monitoring throughout
- Pregnancy: A pregnancy test is required before starting; this medicine can seriously harm or be fatal to an unborn baby
- Contraception: Women who can become pregnant must use effective contraception during treatment and for 7 months after the last dose
- Breastfeeding: It is unknown whether trastuzumab or hyaluronidase passes into breast milk in amounts harmful to a nursing infant; discuss the risks and benefits with your doctor, keeping the 7-month washout in mind
- Older adults: Patients 65 and over have a higher risk of heart problems and should be monitored carefully
- Children: Safety and effectiveness of Herceptin Hylecta have not been established in pediatric patients
- HER2 testing required: Treatment should only be started in patients confirmed to have HER2 protein overexpression or gene amplification by an FDA-authorized test
📡Pharmacodynamics — effects in the body▾
Trastuzumab does not appear to have a meaningful effect on the heart's electrical activity (QTc interval) — meaning it is not expected to cause dangerous heart rhythm changes related to electrical conduction. This was studied specifically in patients with HER2-positive tumors, and no clinically relevant relationship was found between trastuzumab blood levels and changes in the QTc measurement on an ECG (heart tracing).
🔬Pharmacokinetics — how your body processes it▾
After the subcutaneous injection of Herceptin Hylecta, trastuzumab is absorbed through the tissue under the skin, reaching peak blood levels at a median of about 3 days. Hyaluronidase temporarily opens up the subcutaneous tissue to speed up this absorption, with effects reversing within 24 to 48 hours. Trastuzumab reaches steady-state blood levels (a stable plateau) by around the 7th treatment cycle. In most patients, trastuzumab drops below detectable levels by approximately 7 months after the last dose — an important consideration for pregnancy safety and for timing of anthracycline chemotherapy.
📦How to store it▾
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 Trastuzumab and Hyaluronidase-oysk 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 →
🩺 Pharmacist Counseling Corner
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 exactly does Herceptin Hylecta do, and why do I need it? ▾
How is this injection given, and how long does it take? ▾
What side effects should I expect, and which ones mean I need to call my doctor? ▾
Why does my doctor keep checking my heart during treatment? ▾
Is it safe to get pregnant or breastfeed while on this medicine? ▾
Can I take other medicines or chemotherapy alongside this injection? ▾
Is Trastuzumab and Hyaluronidase-oysk Injection available over the counter? ▾
When was Trastuzumab and Hyaluronidase-oysk Injection first available? ▾
💬 Answers drafted from Trastuzumab and Hyaluronidase-oysk 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 Trastuzumab and Hyaluronidase-oysk Injection 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.
Injection
How this form is used
- Herceptin Hylecta is used for adjuvant treatment of HER2-overexpressing node-positive or certain node-negative breast cancer in adults, as part of specific chemotherapy regimens or as a single agent after anthracycline-based therapy
- Herceptin Hylecta is used in combination with paclitaxel for first-line treatment of HER2-overexpressing metastatic breast cancer in adults
- Herceptin Hylecta is used as a single agent for HER2-overexpressing metastatic breast cancer in adults who have already received one or more chemotherapy regimens
- Herceptin Hylecta is given subcutaneously (under the skin) into the thigh — not into a vein — by a healthcare professional over about 2 to 5 minutes, once every three weeks
- Herceptin Hylecta injection sites should be alternated between the left and right thigh; each new injection should be at least 2.5 cm from the previous site on healthy skin
- Herceptin Hylecta must not be substituted for or with ado-trastuzumab emtansine, and must not be given intravenously
- If a Herceptin Hylecta dose is missed, it should be administered as soon as possible; the next dose should be given no sooner than 3 weeks after that
📊 Trastuzumab and Hyaluronidase-oysk Injection across the U.S. market
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.
📈 How widely Trastuzumab and Hyaluronidase-oysk Injection is used
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 1,594 medications we measure, Trastuzumab and Hyaluronidase-oysk Injection ranks #1,397 by Medicaid prescriptions — more than 12% 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 → |
| 10000; 600 U/5 mL; mg/5 mL | Subcutaneous | Genentech, Inc. | BLA | View NDC → |
Showing 2 of 2 products — FDA National Drug Code Directory. See every product, package size and price: browse all 2 Trastuzumab and Hyaluronidase-oysk 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 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.
🏛️ The road to your pharmacy
How Trastuzumab and Hyaluronidase-oysk 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 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.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
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.
🔬 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. Genentech, 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.