Sorafenib and sunitinib in the treatment of advanced non-small cell lung cancer

Despite the optimization of chemotherapy regimens, treatment outcomes for advanced non-small cell lung cancer (NSCLC) are still considered to be disappointing. Thus, clinical research of new treatment strategies is warranted. Several targeted agents have been introduced into clinical trials in NSCLC, but to date, only a few of these new agents can offer hope of a substantial impact on the natural history of the disease. One of the main reasons for the failure of several clinical trials of targeted therapy in lung cancer is that there is multi-level cross-stimulation among the targets of the new biological agents along several pathways of signal transduction that lead to neoplastic events; blocking only one of these pathways, as most first-generation targeted agents do, allows others to act as salvage or escape mechanisms for cancer cells. Sorafenib and sunitinib are two oral multitargeted receptor tyrosine kinase inhibitors. Sorafenib is a multikinase inhibitor that inhibits the kinase activity of both C-RAF and B-RAF and targets the vascular endothelial growth factor receptor family (VEGFR-2 and VEGFR-3) and platelet-derived growth factor receptor family (PDGFR-beta and stem cell factor receptor [ KIT]). Sunitinib is a multitargeted inhibitor of PDGFR, KIT, fms-like tyrosine kinase 3, and VEGFR. The kinases targeted and inhibited by sorafenib and sunitinib directly and indirectly regulate tumor growth, survival, and angiogenesis, and this might be expected to result in broad antitumor efficacy. Sorafenib and sunitinib have been approved by the U. S. Food and Drug Administration for the treatment of metastatic renal cell carcinoma; sunitinib has also been approved for the treatment of gastrointestinal stromal tumors. Their mechanism of action, preclinical data, and phase II studies suggest efficacy in the treatment of advanced NSCLC.