Potent and selective dual ErbB2 (HER-2) and EGFR inhibitor (IC50 values are 9.8 and 10.2 nM, respectively). Selective for EGFR and ErbB-2 versus other proliferative kinases. Inhibits proliferation in multiple cancer cell lines (average IC50 values <0.16 μM). Exhibits 100-fold average selectivity for the tumor cells versus human foreskin fibroblasts. Inhibits EGFR/ErbB2 autophosphorylation and phosphorylation of the downstream modulator AKT. Purity 98%. MW (observed): 581.06