Clinical activity of sorafenib and sunitinib in renal cell carcinoma refractory to previous vascular endothelial growth factor-targeted therapy: two case reports.

Sunitinib and sorafenib are multitargeted receptor tyrosine kinase inhibitors of the vascular endothelial growth factor and platelet-derived growth factor receptor families with antiangiogenic and antitumor activity in metastatic renal cell carcinoma. The utility of these agents in patients refractory to previous treatment with the other agent is unknown. We report 2 cases highlighting that efficacy of these agents is possible after failure of the other agent. Further prospective study is needed.