Unlike other EGFR TKIs that possess a structurally related quinazoline-based core scaffold and were identified as ATP-competitive inhibitors of wild type EGFR, WZ4002 is a covalent pyrimidine EGFR inhibitor specifically designed against EGFR T790M that is 30–100 fold more potent against EGFR T790M, and up to 100 fold less potent against wild type EGFR than quinazoline based EGFR inhibitors in vitro and is effective in murine models of lung cancer driven by EGFR T790M [84]. The gene discussed is EGFR; the disease is lung cancer.