PD 166285 is a potent inhibitor of the tyrosine kinases c-Src, Flg (fibroblast growth factor receptor 1, FGFR1), and PDGFRβ (platelet-derived growth factor receptor β) (IC50 values are 8.4, 39.3 and 98.3 nM respectively). PD 166285 also inhibits the checkpoint kinases Wee1 and MYT1 (Myt1), abolishes Cdc2 phosphorylation in numerous tumor cell lines, and abrogates the G2 checkpoint. PD 166285 is an RTK inhibitor with broad-spectrum properties and displays anti-angiogenic activity and anti-tumor efficacy when used with PDT (photodynamic therapy). PD 166285 is an inhibitor of EGFR.