Beyond bevacizumab: antiangiogenic agents

Angiogenesis is a rational target for the treatment of patients with non-small-cell lung cancer (NSCLC). In the E4599 trial, the vascular endothelial growth factor (VEGF)-targeted antibody bevacizumab combined with carboplatin/paclitaxel improved both progression-free survival (PFS) and overall survival (OS) compared with chemotherapy alone. However responses to bevacizumab are usually transient and resistance inevitably develops. Thus other targets should be considered for future antiangiogenic strategies. A number of antiangiogenic agents with a variety of targets are in clinical development for NSCLC. Several multitargeted receptor tyrosine kinase inhibitors (TKIs) such as sorafenib, cediranib, and BIBF 1120, with activity against vascular endothelial growth factor receptor (VEGFR) and other proangiogenic pathways (eg, fibroblast growth factor [FGF] and platelet-derived growth factor [PDGF] pathways) are in clinical development for NSCLC. Many of these TKIs have shown clinical activity in early trials, both alone and in combination with chemotherapy. Other promising agents in development include inhibitors of the angiopoietin/TIE2 pathway, integrin-targeted agents, vascular disrupting agents, and delta-like ligand-4/Notch pathway inhibitors.