JBJ-09-063 is a mutant-selective allosteric inhibitor of the epidermal growth factor receptor (EGFR), exhibiting potent inhibitory activity with half-maximal inhibitory concentrations (IC50s) of 0.147 nM for EGFR L858R, 0.063 nM for EGFR L858R/T790M, 0.083 nM for EGFR L858R/T790M/C797S, and 0.396 nM for EGFR L747S. This compound effectively decreases phosphorylation of EGFR, Akt, and ERK1/2, demonstrating efficacy in both EGFR tyrosine kinase inhibitor (TKI)-sensitive and resistant models. JBJ-09-063 holds potential for research into EGFR-mutant lung cancer.