Design and Characterization of Imidazole-Based Mutant-Selective ATP-Allosteric Bivalent EGFR Inhibitors

The epidermal growth factor receptor (EGFR) plays a critical role in the carcinogenesis of non-small cell lung cancer (NSCLC) and investigations for targeted small-molecule kinase inhibitors has led to the discovery of several ATP-competitive inhibitor generations and the approval of front-line drug osimertinib. However, the emergence of the highly prevalent C797S mutation within the kinase domain confers resistance to osimertinib and results in cancer recurrence. Recently, EGFR allosteric inhibitors have been developed to overcome drug-resistance mutations, which bind adjacent to the ATP-binding site and dual targeting of both sites exhibits cooperative binding with synergistic effects in certain inhibitor combinations. Here, we report the design and biological evaluation of ATP-allosteric bivalent inhibitors (AABI) that occupy both pockets simultaneously by fusing allosteric inhibitors with an orthosteric binding trisubstituted imidazole scaffold. We elucidate binding properties of differently linked motifs by crystallographic characterization and demonstrate how these molecules can display picomolar enzymatic activity against the L858R/T790M/C797S osimertinib resistance mutation. Structure activity relationships (SAR) generated in this study, define functionalities within the allosteric pocket responsible for potency and mutant-selectivity and covalently binding examples of AABIs exhibit antiproliferative effects in a variety of NSCLC related cancer cells.