This page discusses the use of biologic therapies for the treatment of breast cancer. For a thorough review of biologic therapies for cancer treatment, please see the biologic therapies treatment monograph .

Biologic Therapy (Immunotherapy)

Biologic therapy is a treatment that uses drugs to improve the way your body’s immune system fights disease. Your immune system is your body’s natural defense against disease. A healthy and strong immune system can detect the difference between healthy cells and cancer cells. Biological therapy attempts to repair, stimulate, or enhance the immune system so that it can fight the cancer more effectively. These therapies can be used to fight cancer or to lessen the side effects that may be caused by some cancer treatments.

Monoclonal Antibodies (Herceptin)

For treatment of breast cancer, the most common type of immunotherapy is monoclonal antibody (MOAB) therapy, specifically trastuzumab (Herceptin). MOABs are laboratory-produced substances that are highly specific for a single target antigen.

Trastuzumab has been approved to treat metastatic breast cancer in women with tumors that produce excess amounts of a protein called HER2/neu. Approximately 25% to 30% of breast cancer tumors produce excess amounts of this protein. Tumors that produce excessive amounts of HER2/neu may spread more aggressively. Trastuzumab helps block cancer cell receptors.

Trastuzumab is given intravenously, usually in combination with chemotherapy or other agents. It is usually administered weekly or every 3 weeks.

Effectiveness of Trastuzumab

Trastuzumab has been shown to be effective by itself as an anticancer agent, although studies have demonstrated that it can increase the effectiveness of chemotherapy agents, such as adriamycin or taxanes, when used in combination. Studies are ongoing to see if trastuzumab increases the rates of cure in the treatment of early breast cancer.

Side Effects of Trastuzumab

Possible side effects of trastuzumab include the following:

  • Allergic reactions
  • Red, sore area where injection was given
  • Flu-like symptoms – fever, chills, weakness
  • Fatigue
  • Headache
  • Nausea, vomiting
  • Diarrhea
  • Low blood pressure
  • Rashes

Special Considerations

Trastuzumab may cause an increased risk of cardiac toxicity when combined with anthracycline chemotherapy. Long-term use must be combined with monitoring of heart function.

For more information on biologic therapies, including monoclonal antibodies, please see the biologic therapies treatment monograph.