Discovery of\na Novel Mutant-Selective Epidermal Growth\nFactor Receptor Inhibitor Using an <i>In Silico</i> Enabled\nDrug Discovery Platform

Despite the success of first, second, and third generation\nepidermal\ngrowth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) for\nnon-small cell lung cancer with classical EGFR mutations (L858R or\nExon 19 deletions), disease progression occurs due to the acquisition\nof T790M and C797S resistance. Herein, we report a physics-based computationally\ndriven lead identification approach that identified structurally unique\nimidazo[3.2-<i>b</i>]pyrazoles as reversible and wild-type-sparing\nEGFR TKIs of classical mutations bearing both T790M and C797S. During\nprofiling of imidazo[3.2-<i>b</i>]pyrazoles, we elucidated\nthe bioactivation mechanism causing CYP3A4/5 time-dependent inhibition\n(TDI) and found key modifications to mitigate the TDI. Compound <b>31</b> inhibited EGFR L858R/T790M/C797S in biochemical assays\nwith a <i>K</i><sub>i</sub> = 2.1 nM and EGFR del19/T790M/C797S\nin a Ba/F3 cellular assay with an IC<sub>50</sub> = 56.9 nM. The deuterated\nanalogue of <b>31</b> (<b>38</b>) demonstrated dose-dependent\ntumor growth inhibition in a Ba/F3 EGFR del19/T790M/C797S CDX model\nby 47% at 50 mg/kg BID and 92% at 100 mg/kg BID.