Sunitinib is a small molecule inhibitor of receptor tyrosine kinases, including FLK1 (K
i = 9 nM), PDGFRβ (K
i = 8 nM), and FLT3.
1,2 It is at least 10-fold selective for FLK1 and PDGFRβ over a variety of tyrosine kinases in a panel, including EGFR, Cdk2, Met, IGFR-1, Abl, and Src.
2 Sunitinib inhibits VEGF-dependent FLK1 and PDGF-dependent PDGFRβ phosphorylation (IC
50s = 10 and 10 nM, respectively) as well as phosphorylation of FLT3 and FLT3 carrying the activating internal tandem duplication mutation (FLT3-ITD; IC
50s = 250 and 50 nM, respectively).
1,2 It decreases VEGF- and FGF-induced proliferation of human umbilical vein endothelial cells (HUVECs; IC
50s = 30 and 700 nM, respectively) and reduces tumor growth in a variety of mouse xenograft models when administered at doses ranging from 20 to 80 mg/kg per day.
2 Formulations containing sunitinib have been used in the treatment of gastrointestinal stromal tumors and metastatic renal cell carcinoma.