Drug insight: advances in renal cell carcinoma and the role of targeted therapies.

In metastatic renal cell carcinoma (RCC) immunotherapy results in a small but important improvement in overall survival, but a need exists to develop more-effective systemic therapies. Recent developments in our understanding of the molecular biology of RCC have identified several pathways associated with the development of the disease. A number of strategies designed specifically to target these pathways have resulted. Initial studies have shown marked clinical benefits of so-called 'targeted therapies'. Sunitinib, sorafenib and axitinib are kinase inhibitors that inhibit the VEGF, platelet-derived growth factor and c-kit receptor tyrosine kinases. Bevacizumab is a monoclonal antibody that is directed against VEGF. Temsirolimus inhibits the mammalian target of rapamycin. These agents have all shown considerable activity with manageable toxicity in phase II and III studies in both previously treated and untreated patients. In phase III studies, sorafenib and bevacizumab have been associated with prolonged progression-free survival compared with placebo. Phase III data have shown improvements in progression-free and overall survival with sunitinib and temsirolimus, respectively, compared with interferon alfa. Additional studies are needed to determine the optimum utilization of these agents at the appropriate stage of disease and in the best combinations for maximal clinical benefit.