Herceptin (generic name, trastuzumab) is a monoclonal antibody (a special type of immunotherapy) that was approved by the FDA for the treatment of breast cancer with HER2 over-expression. Herceptin usually is given intravenously in an outpatient setting in clinics.
HER2 (also called HER-2/neu) receptors found on the surface of cells play a key role in regulating cell growth. Some women are born with or experience a mutation of the HER2 gene throughout their lifetime. When the HER2 gene is altered, extra HER2 receptors may be produced on the surface of cells. This over-expression of HER2 causes cells to reproduce more rapidly than normal and may lead to breast cancer.
HER2 protein over-expression affects approximately 25% to 30% of breast cancer patients. Breast cancers that over-express the HER2 gene tend to be aggressive, spread quickly to other regions of the body, and are not as responsive to standard treatments, including certain chemotherapy regimens.
Herceptin seeks out and attaches itself specifically to the HER2 protein receptor on the surface of breast cancer cells. By binding to the cancer cells, Herceptin has been shown to slow the growth and spread of breast tumors that have an overabundance of HER2 protein receptors.