Sunitinib was approved on january 26, 2006 by fda for the treatment of renal cell carcinoma and imatinib-resistant gastrointestinal stromal tumor (gist). sunitinib is a small-molecule which is administered orally and it is multi-targeted receptor tyrosine kinase (rtk) inhibitor. sunitinib inhibits cellular signaling by targeting multiple rtks. these include all platelet-derived growth factor receptors (pdgf-r) and vascular endothelial growth factor receptors (vegf-r). sunitinib also inhibits kit (cd117), the rtk that drives the majority of gists and other rtks including ret, csf-1r, and flt3.