AV-412 is a potent dual inhibitor of EGFR and ErbB2 tyrosine kinases, including the mutant EGFR(L858R,T790M), which is clinically resistant to the EGFR-specific kinase inhibitors erlotinib and gefitinib. In enzyme assays assay the compound inhibited the EGFR variants and ErbB2 in the nanomolar range with over 100-fold selectivity compared with other kinases, apart from ABL and FLT1, which were both moderately sensitive to the compound. In cells, AV-412 inhibited autophosphorylation of EGFR and ErbB2 with IC(50) of 43 and 282 nM, respectively. It also inhibited epidermal growth factor (EGF)-dependent cell proliferation with an IC(50) of 100nM. Moreover, AV-412 abrogated EGFR signaling in the gefitinib-resistant H1975 cell line, which harbors a double mutation of L858R and T790M in EGFR. In animal studies using cancer xenograft models, AV-412 (30mg/kg) demonstrated complete inhibition of tumor growth of the A431 and BT-474 cell lines, which overexpress EGFR and ErbB2, respectively.