Medical Oncologist
HER2-positive breast cancer
Pertuzumab: what adding a second antibody achieves
Pertuzumab is a second HER2-targeted antibody given with trastuzumab and chemotherapy. The two attach to HER2 at different sites, blocking growth signals more completely. This page explains, in general terms, who it is considered for, what it adds and the side effects to know about.
NG
Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
On this page
- What does adding pertuzumab achieve?
- Trastuzumab alone and with pertuzumab
- What adding pertuzumab tends to bring
- What treatment with pertuzumab usually involves
- The vocabulary, in plain language
- Weighing the added benefit
- Questions worth asking your oncologist
- How pertuzumab is used when HER2-positive cancer has spread
- Making treatment days easier
- What people assume about pertuzumab
- Common questions about pertuzumab
The short answer
What does adding pertuzumab achieve?
Pertuzumab is a second HER2-targeted antibody given alongside trastuzumab and chemotherapy. The two antibodies attach to the HER2 protein at different sites, blocking its growth signals more completely than trastuzumab alone. In early breast cancer it is added for some higher-risk HER2-positive cancers, and it is also used in metastatic HER2-positive disease.
Why a second antibody helps
HER2 can partner with related proteins to send growth signals. Pertuzumab blocks that partnering, while trastuzumab blocks signalling in a different way. Together they give a fuller blockade.
Who it is usually considered for
Women with HER2-positive cancer that is larger, involves lymph nodes or is being treated before surgery, and women with metastatic HER2-positive disease. For very small, node-negative cancers, the added benefit is smaller.
Who it may not suit
People with significant heart problems, those who are pregnant, and situations where the added benefit is too small to justify the side effects and cost. Your oncologist weighs these.
This page gives general information only. Whether pertuzumab is right for you is a decision for your oncologist.Side by side
Trastuzumab alone and with pertuzumab
Trastuzumab with chemotherapy
Adding pertuzumab
One antibody blocking HER2
Two antibodies at different sites
Standard for most HER2-positive cancers
Added for higher-risk or metastatic disease
Fewer loose motions
Loose motions and rash more common
Lower drug cost
Higher drug cost
Heart scans needed
Heart scans needed, same schedule
Side effects
What adding pertuzumab tends to bring
Most side effects come from the chemotherapy given at the same time. These are the ones pertuzumab adds or increases.
Loose motions
The most common extra side effect, especially during chemotherapy. Usually manageable with fluids and medicines your team recommends.
Rash and dry skin
An acne-like rash or dry, itchy skin can occur. Gentle moisturisers help, and your team can suggest treatment if it is troublesome.
Report a rash that spreads or blisters.Heart effects
Like trastuzumab, it can occasionally reduce heart pumping. Regular heart scans check for this, and most changes recover.
Infusion reactions
Chills, fever or feeling unwell during or after the first infusion can happen. Nurses watch closely and can slow or pause the drip.
Report promptly
- Breathlessness or swollen ankles
- Loose motions that will not settle
- A fever or shivering
How it is given
What treatment with pertuzumab usually involves
A heart scan first
Heart function is measured before starting, since HER2-targeted drugs can affect it.
A longer first infusion
The first dose is given slowly, with observation afterwards. Later doses are shorter if the first is well tolerated.
Every three weeks
Given alongside trastuzumab every three weeks, with chemotherapy during the early part of treatment.
A combined injection in some centres
A combined pertuzumab and trastuzumab injection under the skin is available in some places, shortening each visit.
Continuing through the year
In early breast cancer it often continues to complete about a year of HER2-targeted treatment, with heart scans every few months.
Words you will hear
The vocabulary, in plain language
- Pertuzumab
- A HER2-targeted antibody given alongside trastuzumab.
- Monoclonal antibody
- A laboratory-made protein designed to attach to one specific target.
- Dual HER2 blockade
- Using two HER2-targeted antibodies together.
- Loading dose
- A larger first dose to reach effective levels quickly, followed by smaller doses.
- Echocardiogram
- An ultrasound scan of the heart used to check pumping function.
- Subcutaneous
- Given as an injection under the skin rather than into a vein.
Talk to our team
Have a question about your situation?
Call the helpline or leave your details, and someone will help you arrange a consultation at the CION centre nearest you. One helpline serves every CION centre.
Call 1800 202 8726
Helpline open 24/7
Being straight with you
Weighing the added benefit
In higher-risk early HER2-positive cancer, adding pertuzumab improves the chance of the cancer not returning, though the extra gain on top of trastuzumab is modest for many women. In metastatic disease, dual blockade has shown a meaningful benefit.
The benefit depends on risk
Women with node-positive or larger cancers tend to gain more. For lower-risk cancers, the added benefit may be small, and some oncologists reserve pertuzumab for higher-risk situations.
Cost is a real factor
Pertuzumab adds considerable cost. It is reasonable to ask how much difference it is likely to make for you, so you can weigh the benefit against the expense.
Side effects are usually manageable
Loose motions and rash are the most common additions. Report them early, because they are easier to control before they become severe.
What this page cannot tell you
It cannot tell you whether pertuzumab would add meaningful benefit for your cancer. Ask your oncologist directly.
Before you decide
Questions worth asking your oncologist
A clear conversation about pertuzumab helps you understand why it is or is not part of your plan.
About the benefit
Ask how much adding pertuzumab is likely to improve your outlook, given the size of your cancer and your lymph node status.
About the practical side
Ask how often you will need to attend, whether a combined injection is available, and how long treatment will last.
About alternatives
Ask what the plan would look like without pertuzumab, and whether any support is available to help with cost.
In metastatic disease
How pertuzumab is used when HER2-positive cancer has spread
In metastatic HER2-positive breast cancer, pertuzumab is commonly part of the first treatment offered, given together with trastuzumab and a taxane chemotherapy. This combination has been shown to help many women live longer than trastuzumab and chemotherapy alone.
After chemotherapy is stopped
Chemotherapy is usually given for a limited number of cycles. If the cancer is responding, the two antibodies often continue on their own every three weeks, sometimes for a long time, which many women find far easier to live with.
Adding hormone therapy
If the cancer is also hormone-sensitive, hormone therapy may be added alongside the antibodies once chemotherapy ends, to help keep the cancer under control.
When treatment changes
If the cancer grows despite treatment, other HER2-targeted options are usually available. Your oncologist will explain what the next step would be.
Day to day
Making treatment days easier
Pertuzumab often continues for months, so small practical steps make a real difference over time.
On infusion days
Eat a light meal beforehand, bring water, something warm to wear and something to pass the time. The first visit is the longest, and later ones are usually much quicker.
Between visits
Keep a small supply of the medicines your team recommends for loose motions, moisturise dry skin daily and keep a short note of any symptoms to mention at your next appointment.
Commonly believed
What people assume about pertuzumab
Everyone with HER2-positive cancer needs pertuzumab.
It is mainly added for higher-risk early cancers and for metastatic disease. Many women with smaller, node-negative cancers are treated with trastuzumab and chemotherapy without it.
Two antibodies means double the side effects.
Pertuzumab mainly adds loose motions and rash. Most of the heavier side effects during this period come from the chemotherapy.
Pertuzumab can replace chemotherapy.
In early breast cancer it is given alongside chemotherapy, not instead of it. The drugs work together.
Loose motions mean I must stop treatment.
They are usually manageable with fluids and medicines. Report them early so your team can help before they become severe.
Questions we are asked
Common questions about pertuzumab
How long is pertuzumab given?
In early breast cancer, often to complete about a year of HER2-targeted treatment. In metastatic disease, it usually continues for as long as it is working and tolerated.
Will it make my hair fall out?
Pertuzumab itself does not usually cause hair loss. Hair loss during this time comes from the chemotherapy given alongside it.
Is there a biosimilar?
Biosimilar availability changes over time. Ask your oncology team what options are currently available to you.
Can I have it as an injection?
A combined pertuzumab and trastuzumab injection under the skin is available in some centres. Ask whether it is offered where you are treated.
What should I do about loose motions?
Drink plenty of fluids and use the medicines your team recommends. Call if loose motions are frequent, continue for more than a day or come with fever.
Is it safe during pregnancy?
No. Effective contraception is needed during treatment and for a period afterwards. Ask your team how long.
Why do I need heart scans?
HER2-targeted drugs can occasionally reduce heart pumping. Regular scans catch changes early, when they usually recover.
Where can I read about this drug?
Your oncology team will give you written information about pertuzumab, including side effects and what to report. Use that as your main reference.
Meet the Specialists
17+ senior cancer specialists. One panel for your case.
Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
Surgical Oncologist
Surgical Oncologist
Dr. Vinay Mamidala
MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)
Surgical Oncologist
Radiation Oncologist
Radiation Oncologist
Radiation Oncologist
Hematologist
Surgical Oncologist
Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
Surgical Oncologist
Want a specific doctor for your case? Mention them when booking.
Book Free ConsultationBook an appointment with our specialist
Share your name and number — we'll call you back within 30 minutes to schedule your consultation.
Where to find us
Our centres in and around Hyderabad
Addressed by landmark, because that is how this city navigates. Each centre also names the areas it serves, so you can place it without a map. Consultation and day-care Chemotherapy run at every one of them.
Warangal
Vizag
Talk to our team
Speak to a breast cancer specialist
Call the helpline or leave your details, and someone will help you arrange a consultation at the CION centre nearest you. One helpline serves every CION centre.
Call 1800 202 8726
Helpline open 24/7
Sources
- Cancer Research UK — Pertuzumab (Perjeta)
- National Cancer Institute — Pertuzumab
- Breast Cancer Now — Pertuzumab
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.