Structure-based rational design and biological evaluation of a quinazoline-based EGFR exon 20 insertion inhibitor

This study describes the structure-based design and synthesis of potent quinazoline-based inhibitors targeting EGFR exon 20 insertion (exon20ins) mutants, one of the challenging oncogenic drivers in non-small cell lung cancer (NSCLC). Guided by in silico modelling, a novel series of quinazoline analogues was designed to incorporate an intramolecular hydrogen bond between the hinge-binding motif and a substituent introduced at the 5-position via an ether linkage. This strategy was hypothesised to pre-organise the inhibitor conformation and improve biochemical inhibitory potency. We synthesised and evaluated 36 compounds, identifying key structure-activity relationships. Notably, we found that the R-configuration of 1-(2-(hydroxymethyl)pyrrolidin-1-yl)prop-2-en-1-one at the 5-position and specific aniline types at the 4-position of quinazoline significantly improved inhibitory activity against EGFR exon20ins in biochemical kinase assays. The most potent analogues exhibited sub-nanomolar IC₅₀ values against various EGFR exon20ins mutants, and these findings could provide useful insights for the development of inhibitors targeting EGFR exon 20 insertions.