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What is Herceptin® ? (trastuzumab)

Herceptin is a targeted treatment used to treat breast cancer that is positive for the human epidermal growth factor receptor 2 (HER2+). It may be used in combination with chemotherapy drugs, or it may be used alone in women who have already received chemotherapy. Herceptin is manufactured by Genentech.

What is the active ingredient in Herceptin?

The active ingredient in Herceptin is trastuzumab, a monoclonal antibody which blocks the HER2 receptor.1

How does Herceptin work?

Herceptin is a monoclonal antibody. Antibodies are a normal part of the immune system that attach to antigens (such as germs) to mark them for destruction by other components in the immune system. Monoclonal antibodies are created in a laboratory to attach to specific antigens on the surface of cancer cells. Herceptin attaches to the HER2 receptor.

Breast cancers that are classified as HER2+ have an excess of HER2 receptors, which can cause the cancer to grow and spread quickly. Herceptin targets these receptors and has been shown to block the growth and spread of HER2+ breast cancers.1,2

What are some of the possible side effects of Herceptin?

Herceptin may cause serious side effects, including1,2:

  • Heart problems, such as congestive heart failure or reduced heart function
  • Infusion reactions, which may cause fever, chills, nausea, vomiting, pain, headache, dizziness, and/or shortness of breath
  • Serious harm to an unborn baby, which may cause serious birth defects or death

The most common side effects experienced by women with metastatic breast cancer receiving Herceptin include1:

  • Fever
  • Chills
  • Headache
  • Congestive heart failure
  • Insomnia
  • Cough
  • Rash
  • Infection

Patients should talk to their doctor about these or any other potential side effects they experience while receiving Herceptin.

Things to know about Herceptin

Because Herceptin can cause birth defects or fatal harm to an unborn fetus, women who can become pregnant who receive Herceptin should use birth control during their treatment and for 7 months after treatment with Herceptin is completed.1,2

Because Herceptin may cause heart damage, heart function tests may be performed before and during treatment with Herceptin. Based on the results of these tests, your treatment with Herceptin may be paused or stopped.1,2

Chemotherapy can cause lowered white blood cell counts. When given in combination with chemotherapy, Herceptin may potentially worsen this effect.1

Dosing information

Herceptin is given as an intravenous (IV) infusion, and the infusion usually takes between 30 and 90 minutes. Other additional treatments, such as chemotherapy, will take additional time for infusion administration when given in combination with Herceptin infusion.

Herceptin Hylecta (trastuzumab and hyaluronidase-oysk), a newer formulation of Herceptin is also approved by the U.S. Food & Drug Administration. Herceptin Hylecta™ is includes the same monoclonal antibody as intravenous Herceptin® (trastuzumab) in combination with recombinant human hyaluronidase PH20, an enzyme that helps to deliver trastuzumab subcutaneously (which means delivered under the skin). Herceptin Hylecta is a ready-to-use formulation that can be administered much more quickly than intravenous Herceptin, reducing administration time to 2 to 5 minutes, compared to 30 to 90 minutes for the intravenous formulation.3,4

Patients should talk to their doctor if they have any questions, or if they have questions regarding their Herceptin regimen.

  1. Herceptin prescribing information. Genentech USA, Inc. Available at Accessed 9/10/18.
  2. Herceptin product website. Available at Accessed 9/10/18.
  3. Genentech. FDA Approves Herceptin Hylecta for Subcutaneous Injection in Certain HER2-Positive Breast Cancers. Accessed March 14, 2019
  4. Herceptin Hylecta Prescribing Information Accessed March 14, 2019