A brain penetrant inhibitor of EGFR (IC50s = 0.3, 0.2, and 0.2 nM for wild-type, L858R-mutant, and exon 19 deletion-containing EGFRs, respectively); selective for EGFR over 115 other kinases, exhibiting 50s = 7.7 and 7.0 nM, respectively) but has no effect on H838 cells that express wild-type EGFR (GI50 = 21,556 nM); inhibits tumor growth by 78% and induces tumor regression at doses of 7.5 and 15 mg/kg, p.o., respectively in a PC-9 mouse model of NSCLC brain metastasis