Animal experiment:

Mice[1]Mice bearing NCI-H1975 EGFR D770_N771insSVD xenografts are orally administered TAS6417 (50, 100, 200 mg/kg). One and 2 hours after administration of TAS6417, xenograft tumors and skin tissues are collected[1].

TAS6417 is an EGFR inhibitor and an efficacious drug candidate for patients with NSCLC, with IC50 values ranging from 1.1-8.0 nM.

TAS6417 inhibits the in vitro phosphorylation activity of EGFR and its mutants including an exon 20 insertion mutation, with IC50 values ranging from 1.1±0.1 to 8.0±1.1 nM. TAS6417 suppresses the growth of cells expressing exon 20 insertion mutations of the EGFR gene, with a GI50 value of 86.5±28.5 nM for LXF 2478L cells and 45.4±2.6 nM for NCI-H1975 EGFR D770_N771insSVD cells. TAS6417 also potently inhibits proliferation in other cell lines harboring activating mutations or acquired resistance mutations, with mean GI50 values of 1.92±0.21 nM to 7.12±0.60 nM. In contrast, the effect of TAS6417 on cell proliferation in normal human epidermal keratinocytes (NHEK-Neo), of which WT EGFR is implicates in the growth and survival, is moderate[1].

TAS6417 causes persistent tumor regression in vivo in EGFR exon 20 insertion-driven tumor models. TAS6417 inhibits mutant EGFR in tumors but not WT EGFR in skin tissues. TAS6417 prolongs survival of animals bearing lung cancer[1].

[1]. Hasako S, et al. TAS6417, A Novel EGFR Inhibitor Targeting Exon 20 Insertion Mutations. Mol Cancer Ther. 2018 Aug;17(8):1648-1658.