Oritinib mesylate (SH-1028) is a highly selective, orally active, pyrimidine-based irreversible inhibitor of epidermal growth factor receptor (EGFR) with a low half maximal inhibitory concentration (IC50) of 18 nM. It demonstrates potent efficacy against both EGFR-sensitive and resistant (T790M) mutations. Furthermore, Oritinib mesylate effectively suppresses the proliferation of tumor cells harboring EGFR mutations, regardless of their sensitivity or resistance.