Naquotinib mesylate (ASP8273 mesylate) is an orally available, mutant-selective and irreversible EGFR inhibitor; with IC 50 s of 8-33 nM toward EGFR mutants and 230 nM for EGFR . In Vitro In assays using endogenously EGFR-dependent cells, Naquotinib inhibits the growth of PC-9(del ex19), HCC827(del ex19), NCI-H1975(del ex19/T790M) and PC-9ER(del ex19/T790M) with IC 50 s of 8-33 nM. Naquotinib selectively inhibits phosphorylation of EGFR and its down-stream signal pathway, ERK and Akt from 10nM in HCC827 and NCI-H1975 while inhibitory effects are only detected at 1000nM in A431.In NCI-H1650 (del ex19), Naquotinib inhibits cell growth with an IC 50 value of 70nM while other EGFR-TKIs are only partially effective. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo Oral Naquotinib treatment dose dependently induces tumor regression in NCI-H1975 (L858R/T790M), HCC827 (del ex19) and PC-9 (del ex19) xenograft models. Dosing schedules does not affect the efficacy of Naquotinib. In an NCI-H1975 xenograft model, complete regression of tumor is achieved after 14-days of Naquotinib treatment. Complete regression is maintained in 50% of mice more than 85 days after cessation of Naquotinib treatment. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:EGFR L858R/T790M EGFR L858R EGFR Exon 19 deletion EGFR Exon 19 deletion/T790M EGFR 230 nM (IC 50 )