Biological therapy uses the body's own immune system to target and fight breast cancer cells.
One such therapy is trastuzumab (Herceptin), a monoclonal ("single") antibody. An antibody is a protein made by the body's own immune system. Trastuzumab is a manmade antibody that can work only if the woman carries and overexpresses the HER2 protein in those tumor cells. About 25% of breast cancer patients carry this gene and are considered HER2 positive. Your doctor should check this on your breast biopsy or on the tumor removed during surgery.
Trastuzumab is the first-line treatment of HER2-positive metastatic breast cancer in combination with chemotherapy drugs. Trastuzumab may also be used alone for HER2-positive metastatic breast cancer.
Pertuzumab (Perjeta) is another monoclonal antibody approved for treatment of HER2-positive metastatic breast cancer or for patients who need neo-adjuvant treatment (treatment before surgery). It is approved for use in combination with trastuzumab and the chemotherapy docetaxel (Taxotere).
Another drug for patients with HER2 positive disease is lapatinib ( Tykerb). It works in HER2-positive patients when trastuzumab is no longer effective. It is used in combination with capecitabine (Xeloda), letrozole (Femara), or trastuzumab.
Ado-trastuzumab emtansine (Kadcyla) is a drug used in patients who have metastatic disease and have already taken trastuzumab and a class of chemotherapy drugs called taxanes, which are commonly used to treat breast cancer. These drugs may have been used together or separately.
Other types of antibodies are being researched to fight cancer and include:
- Angiogenesis inhibitors. These antibodies prevent the growth of new blood vessels, cutting off the supply of oxygen and nutrients to cancer cells. However, the only such drug used for breast cancer, bevacizumab (Avastin), lost its FDA approval for breast cancer because the drug's risks outweighed its benefits and it didn't improve the overall survival of breast cancer patients.
- Signal transduction inhibitors. These antibodies block signals inside the cancer cell that helps the cells divide, stopping the cancer from growing. They are currently being studied to see if they're effective.
Before treatment begins, print out these Questions to Ask to help you better understand your care.
Also see, Follow-Up Care After Your Treatment.
Side Effects of Biological Therapy for Breast Cancer
When biological therapy is used to treat breast cancer, side effects can include:
- Allergic reactions
- Difficulty breathing
- Hypertension (high blood pressure)
- Fever and chills
- Dizziness or weakness
- Heart failure
Talk to your doctor about the possible side effects to watch for and what you should do if they occur. The FDA has warned that treatment with pertuzumab or trastuzumab may be harmful or fatal to a fetus.
Recognizing a Breast Cancer Emergency
- New mouth sores, patches, swollen tongue, or bleeding gums.
- Dry, burning, scratchy, or "swollen" throat.
- Cough that is new or persistent and produces mucus.
- Changes in bladder function, including increased frequency or urgency to go; burning during urination; or blood in your urine.
- Changes in gastrointestinal function, including heartburn; nausea, vomiting, constipation, or diarrhea that lasts longer than two or three days; or blood in stools.