LS-106 is a novel, fourth‐generation EGFR inhibitor against C797S mutation, targeting both EGFR19del/T790M/C797S and EGFRL858/T790M/C797S with selectivity over EGFRwt.LS-106 potently and dose‐dependently inhibited the kinase activity of EGFR19del/T790M/C797S, EGFRL858R/T790M/C797S, EGFRL858R/T790M, and EGFR19del/T790M with IC50 values of 2.4 nM, 3.1 nM, 7.3 nM, and 74.1 nM, respectively.LS-106 exhibited much weaker effect against EGFRwt (IC50=151.5 nM) and EGFR19del (IC50=402.9 nM).LS‐106 not only strongly inhibited the EGFR‐C797S-mutant kinase but also inhibited some other kinases, such as RET, ACK1, and PDGFR‐β.LS‐106 not only inhibited the proliferation of BaF3‐EGFR19del/T790M cells (IC50= 0.09 uM) but also showed over 30‐fold stronger antigrowth activity than osimertinib in BaF3‐EGFR19del/T790M/C797S (IC50= 0.09 uM) and BaF3‐EGFRL858R/T790M/C797S (IC50= 0.12 uM) cells, respectively, elicits significant cell apoptosis in EGFR–triple‐mutant cells.Oral administration of LS‐106 (30 and 60 mg/kg) potently inhibited tumor progression in PC‐9‐OR NSCLC xenograft model with TGI of 83.5% and 136.6%, respecitvely.
