Biologically Targeted Therapy

Biologic therapies are medications that precisely target a specific molecule that is critical to the development of cancer.

In breast cancer, trastuzumab (Herceptin®) is a monoclonal antibody that has been developed to target a protein on the surface of some breast cancer cells known as HER2. A test can be done on the tumor specimen to determine if the HER2 protein is important in a particular cancer. Women with a tumor that tests positive for HER2  may benefit from treatment with trastuzumab, which is generally given in combination with chemotherapy.

The combination of trastuzumab and chemotherapy is much more effective that either treatment given by itself. Until recently, this medication was only used for women with advanced breast cancer who tested positive for the HER2 protein. Recent research has shown that newly diagnosed women with early stages of breast cancer that are HER2-positive also benefit from trastuzumab therapy along with chemotherapy. In this situation, trastuzumab is usually continued after completion of chemotherapy, for up to one year.

What are the side effects of tratuzumab?

Trastuzumab is only available by injection into a vein. The most common side effects with trastuzumab are fever and chills, headache, pain, weakness, and rashes. These side effects tend to be worse after the first treatment and then go away. Some serious, uncommon side effects with trastuzumab include heart damage and breathing difficulties. If your doctor decides that this medication may be of benefit to you, your heart and breathing will be tested and you will be monitored closely throughout your therapy.

Other medications that target the HER2 protein have been developed (lapatinib (Tykerb®), pertuzumab (Perjeta®), and T-DM1 (Kadcyla®). The optimal use of these new medications has not yet been determined and is the subject of is ongoing research. Many other agents targeting different molecules that are important in breast cancer are under development.

Physicians in the Center for Breast Care at the University of Illinois Hospital & Health Sciences System are actively involved in research studies investigating the use of these and other targeted agents in order to improve breast cancer care.