Potent epidermal growth factor receptor (EGFR) kinase inhibitor (IC50 = 0.7 μM) that displays 50-fold and >140-fold selectivity over ErbB2 and insulin receptor kinase respectively. Induce G1 growth arrest selectively in transformed cells (IC50 values are 6.4 and 9.4 μM in HPV16-immortalized and normal keratinocytes respectively).