Although treatment of advanced non-small-cell lung cancer has been improved with the availability of such new agents as the taxanes, topoisomerase inhibitors, vinorelbine (Navelbine), and gemcitabine (Gemzar), platinum-based combination therapy has appeared to reach a threshold of therapeutic effectiveness. A paradigm shift in approach to non-small-cell lung cancer and other tumors may be heralded by the development of agents targeting specific biologic pathways in tumor development. Such new agents include antibody epithelial growth factor receptor (EGFR) inhibitors (eg, the monoclonal antibodies trastuzumab [Herceptin] and cetuximab [IMC-C225, Erbitux]) and EGFR tyrosine kinase inhibitors (eg, ZD1839 [Iressa] and OSI-774), angiogenesis inhibitors (eg, matrix metalloproteinase inhibitors), vascular endothelial growth factor (VEGF) inhibitors (eg, monoclonal antibody to VEGF ligand and small-molecule tyrosine kinase), and signal transduction inhibitors (eg, ISIS-3521, an antisense oligonucleotide to protein kinase C-alpha). A number of these agents have entered advanced-phase clinical investigation. It is likely that targeted therapy will have applications in combination with cytotoxic chemotherapy or radiation therapy at all stages of treatment, including maintenance therapy. It is even possible that these new biologic therapies will be used together as rational combinations (based on pathologic diagnosis) for advanced non-small-cell lung cancer.