Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection
A subcutaneous combination of pertuzumab, trastuzumab, and hyaluronidase used to treat HER2-positive early breast cancer and HER2-positive metastatic breast cancer.
🧬 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 ▾
Phesgo has three serious boxed warnings that every patient should know about.
Heart damage (cardiomyopathy): Phesgo can weaken the heart, sometimes seriously, causing reduced heart pumping function or heart failure. The risk is greatest when it is given alongside anthracycline-type chemotherapy. Your heart function will be tested before you start and regularly during treatment. If your heart is significantly affected, Phesgo will be paused or stopped permanently.
Harm to an unborn baby (embryo-fetal toxicity): Phesgo can cause severe birth defects or death of an unborn baby. This includes reduced amniotic fluid, abnormal lung and skeletal development, and newborn death. Do not use Phesgo if you are pregnant. Use reliable birth control during treatment and for 7 months after your last dose. Tell your doctor immediately if you become pregnant.
Lung toxicity: Phesgo can cause serious and potentially fatal lung reactions, including severe allergic reactions (anaphylaxis), lung inflammation (interstitial pneumonitis), and acute respiratory distress syndrome. Phesgo must be stopped permanently if any of these occur. Watch for new or worsening shortness of breath, wheezing, or swelling of the face or throat and seek emergency care immediately.
📖 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection: Patient Information Guide
A plain-language walkthrough of Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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▾
Phesgo (pertuzumab, trastuzumab, and hyaluronidase-zzxf) is a targeted combination therapy approved for HER2-positive breast cancer in adults. All uses require confirmation of HER2-positive status through an FDA-authorized test before starting treatment.
- Phesgo is used before surgery (neoadjuvant) with chemotherapy for HER2-positive, locally advanced, inflammatory, or early-stage breast cancer (tumor larger than 2 cm or with lymph node involvement), as part of a complete early breast cancer treatment plan
- Phesgo is used after surgery (adjuvant) with chemotherapy for HER2-positive early breast cancer at high risk of returning
- Phesgo is used with docetaxel chemotherapy for HER2-positive metastatic breast cancer (cancer that has spread to other areas of the body) in adults who have not yet received anti-HER2 therapy or chemotherapy for metastatic disease
⚙️How it works▾
HER2 is a protein on the surface of some breast cancer cells that acts like a growth accelerator — when it's overproduced, it drives cancer cells to multiply rapidly. Pertuzumab and trastuzumab are both antibodies designed to latch onto HER2, but they grab different spots. Pertuzumab blocks HER2 from linking up with neighboring proteins (a process called heterodimerization) that trigger growth signals inside the cell. Trastuzumab blocks a different region of HER2 to directly shut down cell proliferation. Together, they also flag cancer cells for destruction by the immune system — a process called antibody-dependent cell-mediated cytotoxicity (ADCC). The third ingredient, hyaluronidase, temporarily softens the tissue under the skin so the two antibodies can be absorbed quickly through a short injection rather than a lengthy IV infusion; this effect is local, reversible, and wears off within 24 to 48 hours.
💊How it's taken▾
Phesgo is given as a subcutaneous injection (under the skin of the thigh only) by a healthcare professional — never self-injected or given into a vein. The first dose is larger and takes about 8 minutes; all follow-up (maintenance) doses are smaller and take about 5 minutes, given every 3 weeks.
- Before surgery (neoadjuvant): Phesgo is given every 3 weeks for 3 to 6 cycles alongside chemotherapy, then continued after surgery to complete 1 year of treatment (up to 18 total cycles)
- After surgery (adjuvant): Phesgo is given every 3 weeks for up to 1 year (up to 18 cycles) as part of a complete regimen including chemotherapy
- Metastatic breast cancer: Phesgo is given every 3 weeks with docetaxel until disease progresses or side effects become unmanageable
- Missed doses: If less than 6 weeks have passed since the last dose, the maintenance dose is given without waiting for the next scheduled date; if 6 or more weeks have passed, a full initial dose is restarted — always follow your care team's guidance
🤒Side effects — in detail▾
The most common side effects with Phesgo in early breast cancer trials included:
- Hair loss (alopecia)
- Nausea
- Diarrhea
- Anemia (low red blood cell count)
- Fatigue or weakness (asthenia)
- Injection site reaction or pain
- Muscle pain (myalgia) and joint pain (arthralgia)
- Decreased appetite
- Headache and nerve tingling (peripheral neuropathy)
- Neutropenia (low white blood cell count), which can increase infection risk
Serious reactions to watch for and act on immediately include signs of heart problems (shortness of breath, unusual swelling, rapid weight gain), severe allergic or injection reactions (throat tightening, hives, difficulty breathing), lung symptoms (new cough, worsening breathlessness), or fever and signs of infection. Get medical help right away if any of these occur.
⚠️Warnings & precautions▾
- Heart damage (cardiomyopathy): Phesgo can reduce the heart's pumping strength, sometimes causing heart failure. Risk is highest with anthracycline chemotherapy. Heart function (LVEF) is monitored before and regularly during treatment. Phesgo is paused or stopped if the heart is significantly affected.
- Fetal harm (embryo-fetal toxicity): Phesgo can cause severe birth defects and fetal death. Effective birth control is required during treatment and for 7 months after the last dose. Pregnancy must be ruled out before starting.
- Lung toxicity: Serious and potentially fatal lung reactions — including anaphylaxis, lung inflammation (interstitial pneumonitis), and acute respiratory distress syndrome — can occur. Phesgo is permanently stopped if these develop.
- Worsening neutropenia: Phesgo can make chemotherapy-related low white blood cell counts worse, increasing the risk of serious infection.
- Hypersensitivity and injection reactions: Reactions at the injection site or whole-body allergic reactions can occur; patients are monitored for at least 30 minutes after the first dose and 15 minutes after every maintenance dose. Emergency medications must be on hand.
🔀What it interacts with▾
Currently, the main known drug interaction with Phesgo involves heart risk with a specific class of chemotherapy:
- Anthracycline chemotherapy (e.g., doxorubicin): Using anthracyclines after stopping Phesgo significantly raises the risk of heart damage because Phesgo remains in the body for a long time (long washout period). If anthracyclines must be used, avoid them for up to 7 months after the last Phesgo dose and monitor heart function carefully throughout.
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▾
- Known allergy to pertuzumab, trastuzumab, or hyaluronidase: Phesgo is contraindicated — do not use it if you have had a serious allergic reaction to any of these ingredients
- Heart problems or low heart pumping function: Your heart must be assessed (by echocardiogram or MUGA scan) before starting and regularly during treatment; Phesgo has not been studied in patients with an LVEF below 55% at the start of treatment
- Pregnancy: Phesgo can cause serious fetal harm or death — pregnancy must be confirmed negative before starting, and effective contraception is required during and for 7 months after treatment
- Breastfeeding: It is not known whether Phesgo passes into breast milk; the long washout period (7 months) must be factored into any decision about nursing
- Lung disease: Patients with existing lung disease or extensive tumor involvement in the lungs may be at higher risk of severe pulmonary reactions
- Older adults (65+): May have higher risk of heart dysfunction, decreased appetite, anemia, and nerve-related side effects — close monitoring is especially important
- Children: Safety and effectiveness in pediatric patients have not been established; Phesgo is not approved for use in children
- Prior anthracycline exposure: Patients who have received high cumulative doses of anthracyclines (above 360 mg/m² of doxorubicin or equivalent) have not been studied with Phesgo
📡Pharmacodynamics — effects in the body▾
The full relationship between Phesgo blood levels and its effects on safety and cancer outcomes has not been completely characterized. Studies of intravenous pertuzumab found no large changes in heart rhythm (QT interval) at standard doses, though a small effect cannot be entirely ruled out. Trastuzumab also showed no clinically meaningful effect on heart rhythm in patients with HER2-positive solid tumors.
🔬Pharmacokinetics — how your body processes it▾
Phesgo is given subcutaneously (under the skin), and hyaluronidase helps the pertuzumab and trastuzumab components absorb into the bloodstream quickly from the injection site. Pharmacokinetic studies (the FeDeriCa trial) compared subcutaneous Phesgo to standard intravenous pertuzumab and trastuzumab to confirm that the drug levels in the blood are therapeutically comparable. Maintenance doses are given every 3 weeks. Because both pertuzumab and trastuzumab stay in the body for a long time, a washout period of approximately 7 months is used for safety decisions, such as timing of pregnancy or anthracycline use after stopping treatment.
📦How to store it▾
Store PHESGO 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.
📄 Written from Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly is Phesgo and why do I need three ingredients in one shot? ▾
Will this affect my heart? What should I watch for? ▾
Can I get pregnant while on Phesgo? ▾
How is the injection given, and will it hurt? ▾
What side effects are most likely and which ones mean I should call someone right away? ▾
Can I switch to Phesgo if I've already been getting pertuzumab and trastuzumab through an IV? ▾
Is Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection available over the counter? ▾
When was Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection first available? ▾
💬 Answers drafted from Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection comes
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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
- Phesgo is used with chemotherapy before surgery (neoadjuvant treatment) for HER2-positive locally advanced, inflammatory, or early-stage breast cancer
- Phesgo is used with chemotherapy after surgery (adjuvant treatment) for HER2-positive early breast cancer at high risk of coming back
- Phesgo is used with docetaxel for HER2-positive metastatic breast cancer in adults who have not yet had anti-HER2 therapy or chemotherapy for metastatic disease
- Phesgo is injected subcutaneously (under the skin) into the thigh only — it must never be given intravenously
- Phesgo must always be administered by a healthcare professional; the initial dose takes about 8 minutes and each maintenance dose takes about 5 minutes
- Phesgo maintenance doses are given every 3 weeks; patients must be observed for at least 30 minutes after the first dose and 15 minutes after each subsequent dose
- Phesgo should not be substituted for or with intravenous pertuzumab, intravenous trastuzumab, or other trastuzumab-based products
📊 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection across the U.S. market
How Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection is used
A general measure of how commonly Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection prescribed? Of the 1,594 medications we measure, Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection ranks #1,010 by Medicaid prescriptions — more than 37% of them.
Utilization by Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 2 of 4 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 2 of 4 listed Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection NDCs with Medicaid activity.
🔍 Compare Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection products
A representative set of FDA-listed product records for Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 | ||||
| PERTUZUMAB 600 mg/10 mL; TRASTUZUMAB 600 mg/10 mL; HYALURONIDASE (HUMAN RECOMBINANT) 20000 U/10 mL | Subcutaneous | Genentech, Inc. | BLA | View NDC → |
| PERTUZUMAB 1200 mg/15 mL; TRASTUZUMAB 600 mg/15 mL; HYALURONIDASE (HUMAN RECOMBINANT) 30000 U/15 mL | Subcutaneous | Genentech, Inc. | BLA | View NDC → |
| 20000; 600; 600 U/10 mL; mg/10 mL; mg/10 mL | Subcutaneous | Genentech, Inc. | BLA | View NDC → |
| 30000; 1200; 600 U/15 mL; mg/15 mL; mg/15 mL | Subcutaneous | Genentech, Inc. | BLA | View NDC → |
Showing 4 of 4 products — FDA National Drug Code Directory. See every product, package size and price: browse all 4 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection belongs to the Endoglycosidase 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.