Potent, irreversible FGFR inhibitor (Kd values are 2.8, 5.4, 6.9 and 120 nM for FGFR1, FGFR3, FGFR2 and FGFR4 respectively); acts at the ATP binding site. Also irreversibly inhibits Flt-1, Flt-4 and VEGFR-2 (Kd values are 32, 120 and 210 nM respectively); displays limited activity (Kd >500 nM) at other kinases. Exhibits antiproliferative activity in FGFR3- and FGFR1-transformed Ba/F3 cells (EC50 values are 10 and 14 nM respectively). Derived from the reversible FGFR inhibitor, PD 173074 (Cat. No. 3044). Purity 96%. MW (observed): 693.06