Dacomitinib is a potent, irreversible pan-ErbB inhibitor, mostly to EGFR with IC50 of 6 nM in a cell-free assay. Dacomitinib inhibits ERBB2 and ERBB4 with IC50 of 45.7 nM and 73.7 nM, respectively. Dacomitinib is effective against NSCLCs with EGFR or ERBB2 mutations (resistant to gefitinib) as well as those harboring the EGFR T790M mutation. Dacomitinib inhibits cell growth and induces apoptosis. Phase 2.