Pertuzumab
- Medical Review: Eleanor "Nora" Taranto, MD, MSCE
Pertuzumab (Perjeta) is a targeted therapy used to treat HER2-positive breast cancer.
Like trastuzumab (Herceptin), pertuzumab is:
- A type of treatment known as a monoclonal antibody — a modified version of an immune system protein that targets HER2 on the surface of breast cancer cells
- A biologic drug, or a drug made from living cells
Pertuzumab is FDA-approved to be given with trastuzumab and chemotherapy:
- Before surgery (neoadjuvant treatment) in early-stage, locally advanced, or inflammatory HER2-positive breast cancer
- After surgery (adjuvant treatment) in early-stage HER2-positive breast cancer that has a high risk of coming back
- To treat HER2-positive metastatic breast cancer
How pertuzumab works
Pertuzumab works by attaching to part of the HER2 protein on breast cancer cells and blocking signals that tell these cells to multiply. After attaching to cancer cells, it can also alert the immune system to kill them.
Who gets pertuzumab
Pertuzumab may be given with trastuzumab after surgery to people with early-stage, HER2-positive breast cancer that is at high risk of returning or spreading outside of the breast.
You may also be able to take pertuzumab as neoadjuvant treatment, treatment given before breast surgery, for early-stage HER2-positive breast cancer if the cancer is:
- Larger than 2 centimeters across, or
- Locally advanced, meaning it has traveled to nearby tissue or lymph nodes, or
- Inflammatory, a type of breast cancer in the skin of the breast that causes the breast to look red and swollen and feel warm to the touch
After getting neoadjuvant treatment and surgery, you will likely continue taking pertuzumab and trastuzumab to complete up to 1 year of treatment.
In metastatic breast cancer, pertuzumab is FDA approved for use with trastuzumab and the chemotherapy docetaxel (Taxotere) for HER2-positive breast cancer that has not yet been treated with trastuzumab or with chemotherapy after a stage IV diagnosis.
The American Society of Clinical Oncology (ASCO) guidelines recommend the combination of trastuzumab and pertuzumab, two medicines that attack HER2 proteins, along with taxane-based chemotherapy, as a first treatment for metastatic breast cancer.
There are ongoing studies testing the combination of pertuzumab with other HER2-targeted therapies such as antibody-drug conjugates (ADCs), including trastuzumab deruxtecan (Enhertu), in metastatic breast cancer.
You and your doctor will discuss the best treatment plan for your situation.
How pertuzumab is given
Pertuzumab is typically given by vein. A needle or a port delivers medicine directly into the vein in a process called an infusion. The first dose is higher, followed by a lower dose for all future treatments. Infusions last between 30 minutes and an hour, after a first infusion that lasts an hour or longer. Infusions are given once every 3 weeks.
Pertuzumab can also be given by injection as pertuzumab, trastuzumab, and hyaluronidase-zzxf (Phesgo). Phesgo delivers both trastuzumab and pertuzumab together by inserting a needle under the skin, usually in the thigh, once every 3 weeks. The injection takes about 5 minutes and the dose is fixed, meaning it doesn’t change based on your weight.
In early-stage breast cancer:
- Your doctor may recommend pertuzumab for up to 18 weeks before surgery along with trastuzumab and the chemotherapies docetaxel and carboplatin (Paraplatin). After surgery, you will likely continue to take pertuzumab infusions along with trastuzumab — or as Phesgo (a combination of pertuzumab, trastuzumab, and hyaluronidase-zzxf) — to complete a year of treatment.
- If recommended only after surgery, pertuzumab and trastuzumab or Phesgo may be taken for up to a year after surgery.
Side effects and things to remember
When pertuzumab is given with trastuzumab and chemotherapy, the side effects people experience most often are:
- Diarrhea
- Fatigue
- Hair loss
- Low white blood cell count, which can lead to infections
- Nausea
- Neuropathy
- Rash
If you are getting chemotherapy and trastuzumab along with pertuzumab, you also may have side effects from trastuzumab and chemotherapy.
Trastuzumab is known to cause heart problems, but studies show that adding pertuzumab to trastuzumab doesn’t raise the risk. It’s unlikely you’ll have serious heart problems while taking these medicines, but it’s important that your doctor monitor your heart health during treatment.
Before starting pertuzumab tell your doctor about any medicines you are taking, including vitamins, herbal supplements and over-the-counter medicines. Pertuzumab may be dangerous to a fetus if taken while pregnant. You should not take it if you are pregnant or breastfeeding, and you should take steps to avoid getting pregnant while on pertuzumab.
Your doctor, pharmacist or nurse can help you manage your side effects. You can also go to our section on side effects for more information.
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Reviewed and updated: January 5, 2026
Reviewed by: Eleanor "Nora" Taranto, MD, MSCE
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Living Beyond Breast Cancer is a national nonprofit organization that seeks to create a world that understands there is more than one way to have breast cancer. To fulfill its mission of providing trusted information and a community of support to those impacted by the disease, Living Beyond Breast Cancer offers on-demand emotional, practical, and evidence-based content. For over 30 years, the organization has remained committed to creating a culture of acceptance — where sharing the diversity of the lived experience of breast cancer fosters self-advocacy and hope. For more information, learn more about our programs and services.