Discovery of a Noncovalent, Mutant-Selective Epidermal Growth Factor Receptor Inhibitor.
Chan BK, Hanan EJ, Bowman KK, Bryan MC, Burdick D, Chan E, Chen Y, Clausen S, Dela Vega T, Dotson J, Eigenbrot C, Elliott RL, Heald RA, Jackson PS, Knight JD, La H, Lainchbury MD, Malek S, Purkey HE, Schaefer G, Schmidt S, Seward EM, Sideris S, Shao L, Wang S, Yeap SK, Yen I, Yu C, Heffron TP.
Inhibitors targeting the activating mutants of the epidermal growth factor receptor (EGFR) have found success in the treatment of EGFR mutant positive non-small-cell lung cancer. A secondary point mutation (T790M) in the inhibitor binding site has been linked to the acquired resistance against those first generation therapeutics. Herein, we describe the lead optimization of a series of reversible, pan-mutant (L858R, del<sub>746-750,</sub> T790M/L858R, and T790M/del<sub>746-750</sub>) EGFR inhibitors. By use of a noncovalent double mutant (T790M/L858R and T790M/del<sub>746-750</sub>) selective EGFR inhibitor (2) as a starting point, activities against the single mutants (L858R and del<sub>746-750</sub>) were introduced through a series of structure-guided modifications. The in vitro ADME-PK properties of the lead molecules were further optimized through a number of rational structural changes. The resulting inhibitor (21) exhibited excellent cellular activity against both the single and double mutants of EGFR, demonstrating target engagement in vivo and ADME-PK properties that are suitable for further evaluation. The reversible, noncovalent inhibitors described complement the covalent pan-mutant EGFR inhibitors that have shown encouraging results in recent clinical trials.