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Perjeta (pertuzumab)
Starting Perjeta can bring up a lot of questions, for you and for the people who love you. Here you'll find what to expect, how to feel your best day to day and where to get help, so you can focus on your life and time together.
ℹ️ General information to help you and your loved ones talk with your care team, not medical advice. Read our disclaimer.
Targeted antibody (HER2-directed) · Used for: Breast cancer
💉 Given by IV or injection · Targeted antibody (HER2-directed)
The quick guide
What it is: Targeted antibody (HER2-directed).
How it's given: An IV infusion every 3 weeks with Herceptin (a combined under-the-skin shot, Phesgo, is also available).
How it works: Perjeta binds HER2 at a different spot than Herceptin, so together they block HER2 more fully. Used for HER2-positive breast cancer before or after surgery and for metastatic disease.
Side effects you may notice, and what helps at home
| Side effect | What can help |
|---|---|
| Diarrhea (loose, watery stools) | Fluids, bland food; ask your team about anti-diarrhea medicine early. |
| Alopecia (hair loss from chemo) | Gentle hair care; ask about scalp cooling. |
| Nausea and vomiting (CINV) | Small bland meals; take anti-nausea medicine as prescribed. |
| Fatigue (extreme tiredness) | Short walks and planned rest. |
| Dermatitis (skin rash and skin changes) | Thick fragrance-free moisturizer, sunscreen, gentle soap. |
Not everyone gets these. Your team may suggest other ways to manage them.
Call your care team now if you have:
- ⚠️ Boxed warning (FDA's most serious): Heart problems (lower heart pumping) and harm to an unborn baby. Your heart is checked before and during treatment.
- Shortness of breath, leg swelling or fast heartbeat (heart problems)
- Severe diarrhea
Call 911 for trouble breathing, chest pain or signs of stroke.
🗓 What to expect
1️⃣ Before you start
- Ask your team for a written schedule and an after-hours phone number.
- Bring a list of all your medicines and supplements.
2️⃣ During each infusion
- You'll get the medicine through an IV in a clinic; nurses check you during the infusion.
- Tell the nurse right away about chills, itching, flushing or trouble breathing.
- Bring a snack, water and something to pass the time.
3️⃣ Between doses
- Watch for the side effects below and use the checklist.
- Keep up with blood tests and visits.
- Call your team for anything in the red box.
✅ Side-effect checklist
Print this and check off what you notice so you can tell your team.
| Side effect | Noticed? | Notes for my team |
|---|---|---|
| Diarrhea (loose, watery stools) | ☐ | |
| Alopecia (hair loss from chemo) | ☐ | |
| Nausea and vomiting (CINV) | ☐ | |
| Fatigue (extreme tiredness) | ☐ | |
| Dermatitis (skin rash and skin changes) | ☐ |
Help paying for Perjeta (pertuzumab)
Perjeta (pertuzumab) is made by Genentech (Roche).
Official manufacturer program:
- Genentech Access Solutions: Insurance help, copay assistance and the Genentech Patient Foundation for free medicine.
Copay cards are usually only for people with commercial (job or marketplace) insurance. If you have Medicare or Medicaid, look at free-drug programs and these independent foundations:
- PAN Foundation: Copays and coinsurance, including for people with Medicare, when a disease fund is open.
- HealthWell Foundation: Grants for copays, deductibles and premiums when a fund is open.
- CancerCare Co-Payment Assistance Foundation: Help with treatment copays for insured people under income limits.
- Good Days: Copay help and some travel costs.
- NeedyMeds: Free database of assistance programs, open to anyone.
📋 Medicare: Medicare Part B usually covers drugs given by infusion in a doctor's office or hospital outpatient clinic. You typically pay 20% after the Part B deductible. See Medicare and your cancer drugs.
More: Help from drug makers · Our guide to paying for cancer treatment.
❓ Questions you and your loved ones can ask
- What is the goal of this treatment for me?
- How will we know if it's working?
- Which side effects should I call about right away, and what number do I call after hours?
- Which medicines, vitamins or supplements should I avoid?
- Will this affect my ability to work, drive or care for my family?
- What will this cost me, and who can help me with coverage?
Support for you and your family
- Susan G. Komen: Breast care helpline, treatment assistance and education
- Living Beyond Breast Cancer: Helpline, peer support and programs for metastatic breast cancer
- CancerCare: Free counseling, support groups and financial help
- Cancer Support Community: Support groups, a helpline and the MyLifeLine online community
Questions people often ask
How does Perjeta work?
Perjeta binds HER2 at a different spot than Herceptin, so together they block HER2 more fully.
How is Perjeta given?
An IV infusion every 3 weeks with Herceptin (a combined under-the-skin shot, Phesgo, is also available).
📄 The official FDA label for Perjeta (pertuzumab), including its patient information section, is on DailyMed.
Written by the Cancer Side Effects Guide team from FDA labels and leading cancer centers. Not medical advice. · Last updated: October 15, 2026 · How we write