Inhibition of angiogenesis in the treatment of non-small cell lung cancer.

Angiogenesis and its role in the growth and development of metastases has become a topic of increasing importance. In non-small cell lung cancer (NSCLC), vascular endothelial growth factor (VEGF) plays an important role in angiogenesis, growth of the primary tumor, and development of metastases. In addition, elevated expression in tissue samples is a negative prognostic feature. For these reasons, VEGF is a worthy target for novel therapies. Recent clinical trials have shown that the anti-VEGF monoclonal antibody bevacizumab adds to the effect of chemotherapy in the metastatic setting. Hypertension and proteinuria are, as expected, commonly seen in this patient population, but the unexpected toxicity of life-threatening hemoptysis has also been observed. This makes careful patient selection especially important for this class of drugs. Our understanding of the VEGF pathway is increasing, as are the number of available targeted agents. In addition to the monoclonal antibody, bevacizumab, VEGF receptor tyrosine kinase inhibitors, multitargeted kinase inhibitors, and combination VEGF and epidermal growth factor receptor (EGFR) inhibition, are all being evaluated in NSCLC. Small phase I and II trials have suggested modest benefit when used alone; however, we now know that the anti-angiogenic therapies work best in combination with chemotherapy. The results of ongoing trials using these agents in combination with standard therapy will provide more insight into their potential benefit. As it is known that small tumors require angiogenesis to grow and metastasize, the use of anti-angiogenic therapies in the adjuvant setting may provide even greater benefit, and increase the potential cure rate in this population of patients. The results of well-designed phase III trials will be required to truly understand how to best use this class of targeted therapies in resectable and metastatic NSCLC.