Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection (Phesgo) is a combined injection under the skin that treats HER2-positive breast cancer, both early-stage and metastatic.
🧬 Where this information comes from
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 →
Phesgo pairs two HER2-blocking antibodies, pertuzumab and trastuzumab, which shut off a growth signal on breast cancer cells and help the immune system attack them, with hyaluronidase, which loosens tissue so the dose goes under the skin; brand-only since about 2020, it is a quicker alternative to the standard by-vein antibody pair given with chemotherapy in early or metastatic HER2-positive breast cancer. Phesgo itself is usually well tolerated; diarrhea and a sore injection site are common, and hair loss mostly comes from the chemotherapy. Its boxed warning covers heart damage, harm to a pregnancy and serious lung problems, so keep every heart check and report breathlessness or leg swelling quickly.
Clinical pearls
- Plan to stay for observation after each shot, at least 30 minutes after the first one and 15 minutes after later ones.
- Use effective birth control during treatment and for 7 months after the last dose, because the drug lingers that long.
- Any doctor planning doxorubicin or another anthracycline within 7 months of your last dose needs to know you had Phesgo.
- Call about any fever, since Phesgo can deepen the drop in white blood cells that chemotherapy causes.
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾
Phesgo can cause serious heart problems, serious harm to an unborn baby, and serious or fatal lung problems.
- Heart: It can weaken the heart and cause heart failure, even without symptoms at first. The risk is highest with anthracycline chemotherapy. Your heart will be checked before and during treatment, and Phesgo may be stopped or paused.
- Pregnancy: It can cause miscarriage or birth defects, including low amniotic fluid that can lead to lung and skeletal problems and death in newborns. Effective birth control is needed.
- Lungs: It can cause serious lung problems. Treatment is stopped for severe allergic reactions, swelling, lung inflammation, or acute respiratory distress syndrome.
Patient Information Guide A plain-language walkthrough of Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection, written from its FDA label.
What Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection Is Used For
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Phesgo is used for HER2-positive breast cancer in adults.
- Early breast cancer, before surgery: Phesgo is used with chemotherapy for locally advanced, inflammatory, or early-stage disease (larger than 2 cm or node positive).
- Early breast cancer, after surgery: Phesgo is used with chemotherapy for early breast cancer at high risk of coming back.
- Metastatic breast cancer: Phesgo is used with docetaxel in people who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease.
How Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection Works
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Pertuzumab and trastuzumab attach to different parts of the HER2 protein on cancer cells. This blocks signals that tell the cells to grow and divide, and it helps the immune system target those cells. Used together, they worked better against HER2-driven tumors in lab models than pertuzumab alone.
Hyaluronidase temporarily loosens the tissue under the skin so the medicine can be absorbed. Its effect wears off within 24 to 48 hours.
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection Dosage
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Phesgo is injected under the skin of the thigh by a healthcare professional. It is never given into a vein.
- The first injection is longer, then it is given every 3 weeks.
- Before surgery, it is given for 3 to 6 cycles with chemotherapy.
- After surgery, treatment continues to complete 1 year, or until the cancer returns or side effects become unmanageable.
- For metastatic disease, it continues until the cancer progresses or side effects become unmanageable.
- If a dose is late or missed, your care team decides which dose to give based on how long it has been.
Dosing details from the FDA-approved label
From the Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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.
- Initial dose (all indications)
- 1,200 mg pertuzumab, 600 mg trastuzumab, and 30,000 units hyaluronidase in 15 mL administered subcutaneously over approximately 8 minutes
- No dose adjustments required for patient body weight or concomitant chemotherapy regimen
- Maintenance dose (all indications)
- 600 mg pertuzumab, 600 mg trastuzumab, and 20,000 units hyaluronidase in 10 mL administered subcutaneously over approximately 5 minutes every 3 weeks
- No dose adjustments required for patient body weight or concomitant chemotherapy regimen
- Neoadjuvant treatment of breast cancer
- Administer PHESGO every 3 weeks for 3 to 6 cycles as part of a treatment regimen for early breast cancer
- Following surgery, continue PHESGO to complete 1 year of treatment (up to 18 cycles) or until disease recurrence or unmanageable toxicity, whichever occurs first
- Adjuvant treatment of breast cancer
- Administer PHESGO every 3 weeks for a total of 1 year (up to 18 cycles) or until disease recurrence or unmanageable toxicity, whichever occurs first
- Start PHESGO on Day 1 of the first taxane-containing cycle
- Maximum: up to 18 cycles
- Metastatic breast cancer (MBC)
- PHESGO every 3 weeks with docetaxel
- Recommended initial dose of docetaxel is 75 mg/m2 as an intravenous infusion, may be escalated to 100 mg/m2 every 3 weeks if the initial dose is well tolerated
- Administer PHESGO until disease progression or unmanageable toxicity, whichever occurs first
- Transition from intravenous pertuzumab and trastuzumab, less than 6 weeks since last dose
- PHESGO maintenance dose of 600 mg pertuzumab/600 mg trastuzumab, then every 3 weeks
- Transition from intravenous pertuzumab and trastuzumab, 6 weeks or more since last dose
- Initial dose of 1,200 mg pertuzumab/600 mg trastuzumab, followed by maintenance dose of 600 mg pertuzumab/600 mg trastuzumab every 3 weeks
- Delayed or missed doses, less than 6 weeks between two sequential injections
- Administer the maintenance dose of 600 mg, 600 mg, and 20,000 units/10 mL
- Do not wait until the next planned dose
- Delayed or missed doses, 6 weeks or more between two sequential injections
- Re-administer the initial dose of 1,200 mg, 600 mg, and 30,000 units/15 mL, followed every 3 weeks thereafter by a maintenance dose of 600 mg, 600 mg, and 20,000 units/10 mL
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION For subcutaneous use in the thigh only. ( 2.2 ) PHESGO has different dosage and administration instructions than intravenous pertuzumab and trastuzumab products. ( 2.2 ) Do not administer intravenously. ( 2.2 ) Perform HER2 testing using FDA-authorized tests by laboratories with demonstrated proficiency. ( 1 , 2.1 ) The initial dose of PHESGO is 1,200 mg pertuzumab, 600 mg trastuzumab, and 30,000 units hyaluronidase administered subcutaneously over approximately 8 minutes, followed every 3 weeks by a dose of 600 mg pertuzumab, 600 mg trastuzumab, and 20,000 units hyaluronidase administered subcutaneously over approximately 5 minutes. ( 2.2 ) Neoadjuvant: administer PHESGO by subcutaneous injection every 3 weeks and chemotherapy by intravenous infusion preoperatively for 3 to 6 cycles. ( 2.2 ) Adjuvant: administer PHESGO by subcutaneous injection every 3 weeks and chemotherapy by intravenous infusion postoperatively for a total of 1 year (up to 18 cycles). ( 2.2 ) MBC: administer PHESGO by subcutaneous injection and docetaxel by intravenous infusion every 3 weeks. ( 2.2 ) 2.1 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. 2.2 Important Dosage and Administration Information PHESGO is for subcutaneous use only in the thigh. Do not administer intravenously. PHESGO has different dosage and administration instructions than intravenous pertuzumab, intravenous trastuzumab, and subcutaneous trastuzumab when administered alone. Do not substitute PHESGO for or with pertuzumab, trastuzumab, ado-trastuzumab emtansine, or fam-trastuzumab deruxtecan.
Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection Side Effects
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Common side effects include:
Common side effects
- Hair loss
- Nausea
- Diarrhea
- Anemia (low red blood cells)
- Weakness or tiredness
- Injection site reactions
- Low white blood cell counts (neutropenia)
When to get medical help
- Call your care team right away if you have shortness of breath, swelling in your legs or feet, a fast or irregular heartbeat, or sudden weight gain. These can be signs of heart problems.
- Get emergency help for trouble breathing, swelling of the face or throat, hives, or a severe allergic reaction.
- Report new cough, wheezing or breathing trouble, which can signal a serious lung problem.
- Tell your team about fever or signs of infection, since low white blood cell counts can be serious.
- Tell your doctor right away if you are or may be pregnant.
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection Warnings and Precautions
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- Heart damage: Heart function is checked before and during treatment, and afterward for at least 2 years.
- Pregnancy harm: It can cause birth defects and fetal death.
- Lung toxicity: It can be serious or fatal.
- Low white blood cells: It can worsen neutropenia from chemotherapy.
- Allergic and injection reactions: These can be severe.
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection Interactions
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The main concern is anthracycline chemotherapy.
- Anthracyclines: They raise the risk of heart problems, including when given after Phesgo is stopped, because Phesgo stays in the body a long time.
- Other HER2 medicines: Phesgo should not be substituted for pertuzumab, trastuzumab, ado-trastuzumab emtansine, or fam-trastuzumab deruxtecan.
Interactions listed in the FDA-approved label
From the Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.
- Anthracyclines (given after stopping PHESGO): Patients who receive anthracycline after stopping PHESGO may be at increased risk of cardiac dysfunction because of PHESGO's long washout period. If possible, avoid anthracycline-based therapy for up to 7 months after stopping PHESGO. If anthracyclines are used, carefully monitor the patient's cardiac function.
Read the label’s full interactions text
7 DRUG INTERACTIONS Patients who receive anthracycline after stopping PHESGO may be at increased risk of cardiac dysfunction because of PHESGO's long washout period [see Clinical Pharmacology (12.3) ] . If possible, avoid anthracycline-based therapy for up to 7 months after stopping PHESGO. If anthracyclines are used, carefully 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection
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- Do not use it with a known allergy to its ingredients.
- Tell your doctor about heart or lung disease.
- Pregnancy should be ruled out before starting.
- Use effective birth control during treatment and for 7 months after the last dose.
- Talk with your doctor about breastfeeding.
- It has not been established as safe or effective in children.
- Older adults may have more heart and other side effects.
What Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection Does in the Body
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The label notes that the relationship between drug exposure and effect for Phesgo is not fully characterized. In a small study, pertuzumab showed no large changes in the heart's QT interval, though a small increase could not be ruled out. Trastuzumab had no clinically relevant effect on the QT interval.
How Your Body Processes Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection
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Phesgo is injected under the skin, and hyaluronidase helps the antibodies get absorbed. The medicine stays in the body for a long time, with a washout period of about 7 months. That is why pregnancy precautions and anthracycline cautions continue after the last dose.
How to Store Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection
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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 the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection: Pharmacist Answers to Common Questions
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 is Phesgo used for?
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How will I get it?
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What side effects should I expect?
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When should I call my doctor right away?
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Is it safe in pregnancy?
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Does it interact with other cancer drugs?
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Is Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection available over the counter?
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When was Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection on HelloPharmacist
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection Forms and Strengths (How It 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.
Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection inactive ingredients by manufacturer.
Injection
How this form is used
- Phesgo is used with chemotherapy before or after surgery for HER2-positive early breast cancer.
- Phesgo is used with docetaxel for HER2-positive metastatic breast cancer in people who have not had prior anti-HER2 therapy or chemotherapy for metastatic disease.
- Phesgo is injected under the skin of the thigh only and never into a vein.
- Phesgo is always given by a healthcare professional.
- Phesgo is given about every 3 weeks, with a longer first dose, and you are watched afterward for reactions.
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection on the U.S. Market: Products, Makers and Brands
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.
1 company lists 2 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection product records with the FDA, mostly as injection; the earliest marketing or approval year on record is 2020. Brand names on the directory include Phesgo; the rest are generics.
How Widely Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection Is Used (Medicaid Data)
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 1,603 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 → |
Showing 2 of 2 products — FDA National Drug Code Directory. See every product, package size and price: browse all 2 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection NDCs →
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 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.
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection FDA Approval History
How Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection was first approved by the FDA in 2020 (Brand: PHESGO · Genentech Inc). It remains available in U.S. pharmacies today.
Source: Drugs@FDA.
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf recalls since July 2021.
✅No Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Oct 8, 2026.
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection Supply and 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.
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection Brand Names
Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection is sold under one brand name in the FDA directory — Phesgo. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who Makes Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf Injection: Manufacturers and Labelers
One company lists Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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.
Sources for This Pertuzumab, Trastuzumab, and Hyaluronidase-zzxf 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 →