Combining targeted therapies and drugs with multiple targets in the treatment of NSCLC

The first generation of clinical trials of targeted agents in non-small cell lung cancer (NSCLC) treatment has concluded. To date, only a few of these new agents can offer hope of a substantial impact on the natural history of the disease. Nevertheless, clinically meaningful advances have already been achieved. In chemotherapy-refractory advanced NSCLC patients, gefitinib and erlotinib, two epidermal growth factor receptor tyrosine kinase inhibitors, represent a further chance for tumor control and symptom palliation. In chemotherapy-naive, advanced, nonsquamous NSCLC patients, the combination of the anti-vascular endothelial growth factor monoclonal antibody bevacizumab with chemotherapy was demonstrated to produce better survival outcomes than with chemotherapy alone. The relative failure of first-generation targeted therapies in lung cancer may be a result of multilevel cross-stimulation among the targets of the new biological agents. Thus, blocking only one of these pathways allows others to act as salvage or escape mechanisms for cancer cells. Preclinical evidence of the synergistic antitumor activity achievable by combining targeted agents that block multiple signaling pathways has recently been emerging. Clinical trials of multitargeted therapy may represent the second generation of studies in this field, and some of these are already ongoing. In a recent phase I/II trial, the combination of erlotinib and bevacizumab demonstrated very promising activity in the treatment of advanced NSCLC pretreated with chemotherapy. Whether the multitargeted approach is best performed using combinations of selective agents or agents that intrinsically target various targets is a matter of debate.