Toxicities of Antiangiogenic Therapy in Non–Small-Cell Lung Cancer

The addition of antiangiogenic agents has improved overall survival in a wide variety of tumor types, including non–small-cell lung cancer (NSCLC). Antibodies to the vascular endothelial growth factor (VEGF) were the first targeted agent to yield a significant improvement in overall survival when combined with first-line chemotherapy for metastatic NSCLC. Anti-VEGF antibodies and tyrosine kinase inhibitors blocking VEGF receptor (VEGFR) activity are also being investigated in pretreated NSCLC. Initial experience with anti-VEGF antibodies suggested a mild adverse event profile. However, it has become clear with additional experience that antiangiogenic agents are associated with a distinct array of toxicities, such as hemorrhage, hypertension, thromboembolic events, and proteinuria. Furthermore, an increase in chemotherapy-associated toxicities such as neutropenia has been observed with the addition of anti-VEGF antibodies. Multitargeted small-molecule inhibitors that block activity of the VEGFR tyrosine kinase are associated with fatigue and other toxicities in addition to the aforementioned class-effect toxicities, possibly because of their inhibition of multiple signaling pathways. Currently, only patients without predominant squamous cell histology are eligible to receive bevacizumab. Trials are ongoing to address the feasibility of bevacizumab in patients who were excluded from the phase III pivotal trial. Additionally, further investigation is necessary to determine risk factors for hemorrhage with antiangiogenic agents.