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How Does Herceptin Work?

Herceptin (trastuzumab) is not chemotherapy or hormonal therapy. Herceptin is a type of targeted cancer therapy known as a monoclonal antibody (sometimes called targeted biologic therapy). Antibodies are part of the body's normal defense against bacteria, viruses, and abnormal cells, such as cancer cells. 1,4

  • Monoclonal antibodies are produced in a laboratory by making multiple copies of a single cell. Monoclonal antibodies are designed to recognize a specific protein on certain cells and signal the body's immune system to destroy the cell 2
  • Monoclonal antibodies are generally a more targeted therapy than chemotherapy 2,3

To receive Herceptin, your tumor must be tested and be HER2+. Talk to your doctor to find out if Herceptin is right for you.

How Herceptin Works or Herceptin works with immune system to restrict HER2+ cancer cell growth

How Herceptin works

Herceptin is designed to target HER2+ cancer cells. Based on laboratory studies, Herceptin is thought to work in two ways to stop the HER2+ cancer cell from growing. 1

Who is Herceptin for?

Herceptin is approved for the adjuvant treatment of HER2-overexpressing, node-positive or node-negative (ER/PR-negative or with one high-risk feature)† breast cancer. Herceptin can be used several different ways:

  • As part of a treatment regimen including doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel
  • With docetaxel and carboplatin
  • As a single agent following multi-modality anthracycline-based therapy

† High-risk is defined as ER/PR positive with one of the following features: tumor size >2 cm, age <35 years, or tumor grade 2 or 3.

What important safety information should I know about Herceptin?

Herceptin treatment can result in heart problems, including those without symptoms (reduced heart function) and those with symptoms (congestive heart failure). The risk and seriousness of these heart problems were highest in people who received both Herceptin and a certain type of chemotherapy (anthracycline). Your doctor will stop or strongly consider stopping Herceptin if you have a significant drop in your heart function.

You should be monitored for decreased heart function before your first dose of Herceptin, and frequently during the time you are receiving Herceptin and after your last dose of Herceptin. If you must permanently or temporarily stop Herceptin due to heart problems, you should be monitored more frequently. In one study with Herceptin and certain types of chemotherapy, an inadequate blood supply to the heart occurred.

Some patients have had serious infusion reactions and lung problems; fatal infusion reactions have been reported. In most cases, these reactions occurred during or within 24 hours of receiving Herceptin. Your Herceptin infusion should be temporarily stopped if you have shortness of breath or very low blood pressure. Your doctor will monitor you until these symptoms go away. If you have a severe allergic reaction, swelling, lung problems, inflammation of the lung, or severe shortness of breath, your doctor may need to completely stop your Herceptin treatment.

Worsening of low white blood cell counts associated with chemotherapy has also occurred.

Herceptin can cause low amniotic fluid levels and harm to the fetus when taken by a pregnant woman.

The most common side effects associated with Herceptin were fever, nausea, vomiting, infusion reactions, diarrhea, infections, increased cough, headache, fatigue, shortness of breath, rash, low white and red blood cells, and muscle pain.

Because everyone is different, it is not possible to predict what side effects any one person will have. If you have questions or concerns about side effects, talk to your doctor.

Please see the Herceptin full Prescribing Information including Boxed WARNINGS and additional important safety information.



Herceptin® (trastuzumab)Herceptin® (trastuzumab)

Adjuvant Care Is defined as additional treatment given after the main treatment plan to decrease the chance of recurrence. Adjuvant therapy for breast cancer can include chemotherapy, hormone therapy, radiation therapy, or biological therapy

Metastatic Breast Cancer Breast cancer that has spread to other sites in the body; also referred to as invasive or infiltrating