Adjuvant anti-HER2 monoclonal antibody therapy - Ready for breast cancer?

A large number of patients diagnosed with early breast cancer worldwide derive improvements in disease-free survival (DFS) and overall survival with the use of available systemic adjuvant therapies. However, there is still much work to be done. Further improvements in clinical outcomes will significantly depend on the identification of prognostic and therapeutic targets through molecular medicine. The paradigm for these biological determinants is exemplified by HER2 and the chimeric humanized antibody that targets the extracellular domain of the HER2 gene product (HER2) in advanced breast cancer, trastuzumab. In clinical trials, this anti-HER2 monoclonal antibody has been demonstrated to be active as a single agent and has been shown to improve survival when it is added to two standard chemotherapy regimens in patients with metastatic breast cancer. Thus, it is logical that randomized phase III clinical trials have been designed and initiated to determine whether trastuzumab improves the efficacy of chemohormonal adjuvant treatment for patients at high risk of tumuor relapse based on amplification of the HER2 gene and/or HER2 protein overexpression.