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The U.S. Food and Drug Administration (FDA) has announced the approval of the drug Herceptin (generic name, trastuzumab) for use in early stage breast cancer patients after treatment with surgery - either mastectomy or lumpectomy. The approval comes after two large government-funded studies found that Herceptin reduce relapses after treatment. Herceptin is only approved for women with a certain type of breast cancer called HER 2-positive breast cancer. HER2 (human epidermal growth factor receptor 2) is a protein found on the surface of cells that, when functioning normally, has been found to be a key component in regulating cell growth. However, when the HER2 protein is altered, extra HER2 protein receptors may be produced. This over-expression of HER2 causes increased cell growth and reproduction, often resulting in more aggressive breast cancer cells. Women with HER2 over-expression may not be as responsive to standard breast cancer treatments, including certain regimens of chemotherapy. Herceptin works by targeting breast cancer cells that have too many copies of the HER2 protein. After it has identified which cells over-express the HER2 protein, Herceptin attaches itself to the HER2 protein receptors on the surface of these cells. By binding to the cells, Herceptin slows the growth and spread of tumors that have an overabundance of HER2. Many experts believe that Herceptin represents the future direction of breast cancer drugs in that it targets a particular protein of the cancer cell and prevents it from carrying out its action, similar to the leukemia drug, Gleevec. In 1998, the FDA approved Herceptin for the treatment of metastatic breast cancer (cancer that has spread to other body organs). The FDA's recent approval expands its use to women with cancer only in the breast or lymph nodes which has been removed with surgery. The approval comes after two large government-funded studies found that Herceptin can significantly reduce the recurrence of breast cancer, when given in combination with chemotherapy. The studies involved over 3,300 women with HER2 positive breast cancers. Patients were randomly selected to receive either standard chemotherapy (with the drugs doxorubicin and cyclophosphamide) followed by treatment with the drug paclitaxel, or the same form of standard chemotherapy followed by treatment with the drugs paclitaxel and Herceptin. Most patients who enrolled in the studies had breast cancers that had spread to their nearby lymph nodes. Women who were treated with chemotherapy and Herceptin were significantly less likely to experience a recurrence of their disease. "This is a major advance for many thousands of women with breast cancer," said U.S. National Cancer Institute Director Andrew C. von Eschenbach, MD, in an NCI news release. "These results are one more example that we are at a major turning point in the use of targeted therapies to eliminate suffering and death from cancer." Other cancer experts agreed that the studies are a significant advance in targeted breast cancer treatment. "These are truly life-saving results in a major disease," said JoAnne Zujewski, MD of the National Cancer Institute, in an NCI news release. Edward Romond, MD, study chair for the National Adjuvant Breast and Bowel Project and professor of oncology at the University of Kentucky, in Lexington, Kentucky, noted, "For women with this type of aggressive breast cancer, the addition of [Herceptin] to chemotherapy appears to virtually reverse prognosis from unfavorable to good." According to the FDA, the most serious side effect of Herceptin is heart failure (weakening of the heart muscle) that requires medical treatment. Due to the risk of heart disease, only certain patients should receive the drug, including:
Women who receive Herceptin must be screened for heart function before beginning and during treatment. According to the FDA, less common but serious side effects include infusion reactions (chills, fever, shortness of breath) that rarely are accompanied by lung problems, low white blood counts, and low red blood cell counts.
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