Nazartinib mesylate is a novel, covalent mutant-selective inhibitor of EGFR (Ki and Kinact: 31 nM and 0.222/min on EGFR(L858R/790M) mutant).

EGFR (L858R/T790M):31 nM （ki）

Nazartinib inhibits cell proliferation (EC50: 9, 11, and 25 nM in H3255, HCC827, and H1975, respectively). Nazartinib has an inhibitory effect on the mutant cell lines (IC50s: 4, 6, 2 nM in H1975, H3255, and HCC827, respectively). It also shows improved ADME and PK properties [1]. Nazartinib has an OC50 value of 2 and 5 nM on HCC827 and H1975, respectively. Nazartinib displays potent inhibition of pEGFR levels in H3255, HCC827, and H1975 cell lines ( EC50: 5, 1, and 3 nM, respectively) [2].

Nazartinib (50 and 20 mg/kg or 25 mg/kg, p.o.) demonstrates dose-dependent efficacy with near-complete tumor cells regression at the highest dose tested (50 mg/kg), in H1975 mouse xenograft model [1]. Nazartinib (30 mg/kg, p.o.) displays significant antitumor activity, in the H3255 xenograft model. In the H1975 mouse model, Nazartinib (10 mg/kg, p.o.) induces tumor growth inhibition with a T/C (tumor/control volume) of 29%, and when doses are 30 and 100 mg/kg, tumor regressions are achieved (T/C, ?61% and ?80%, respectively). Antiproliferative activity of Nazartinib on 89 lung cancer cell lines indicates that Nazartinib selectively inhibits cell lines containing EGFR with catalytic domain mutations [2].