First line targeted therapies in breast cancer: focus on bevacizumab

The heterogeneity of metastatic breast cancer mandates the need to select therapies taking into account tumor and patient characteristics. Chemotherapy is indicated in the palliative setting especially when the disease is unresponsive to hormonal therapy or is hormone-receptor negative. The main chemotherapeutic agents are anthracyclines, taxanes, and capecitabine. The knowledge of the effects of currently approved agents and of the biology of breast cancer have paved the way for the evaluation of new treatment options, among which are anti-angiogenic agents. Angiogenesis inhibition has resulted in clinically significant improvements in the outcome of a variety of malignancies, including breast cancer. Bevacizumab, a monoclonal antibody anti-vascular endothelial growth factor (VEGF), is the most extensively studied anti-angiogenic compound. According to the results of a phase III trial in patients with untreated metastatic breast cancer, bevacizumab increases both objective response rate and median progression-free survival when combined with standard chemotherapy vs chemotherapy alone. The combination of anti-angiogenic drugs and other biologic agents is also being explored in an attempt to improve efficacy.