Novel third-generation pyrimidines-based EGFR tyrosine kinase inhibitors targeting EGFR T790M mutation in advanced non-small cell lung cancer

The critical T790M secondary mutation in epidermal growth-factor receptor (EGFR) mediates resistance to first- and second-generation EGFR tyrosine kinase inhibitors. Herein, we identified 12 new 2,4-diaryl pyrimidine derivatives containing thiophene fragments as new selective third-generation EGFR inhibitors. Among them, Compound 6a showed good inhibitory activity against EGFR mutant cells with an IC50 value of 0.0022 ± 0.001 μM and was approximately 1730-fold less potent against EGFR WT cells (IC50: 4.499 ± 0.057 μM). Moreover, it strongly affected EGFR-mediated signaling pathways, attenuated tumor proliferation via the intrinsic mitochondrial apoptotic pathway, arrested the cell cycle at G0/G1 phase, and induced apoptosis in H1975 cells. It also displayed appropriate pharmacokinetic (PK) parameters with an oral bioavailability value of 33.57%. Additionally, in vivo studies confirmed that 6a suppressed tumor growth in an H1975 xenograft model (25 mg/kg/d, TGI: 90.24%). Overall, these results suggest that 6a could be a promising lead compound for overcoming the clinical EGFR T790M resistance of patients with non-small-cell lung cancers (NSCLCs).