Conclusions
Together, these data demonstrate that glesatinib exhibits a distinct mechanism of target inhibition and can overcome resistance to type I MET inhibitors. Clin Cancer Res; 23(21); 6661-72. ©2017 AACR.
Purpose
MET exon 14 deletion (METex14 del) mutations represent a novel class of non-small cell lung cancer (NSCLC) driver mutations. We evaluated glesatinib, a spectrum-selective MET inhibitor exhibiting a type II binding mode, in METex14 del-positive nonclinical models and NSCLC patients and assessed its ability to overcome resistance to type I MET inhibitors.Experimental Design: As most MET inhibitors in clinical development bind the active site with a type I binding mode, we investigated mechanisms of acquired resistance to each MET inhibitor class utilizing in vitro and in vivo models and in glesatinib clinical trials.
Results
Glesatinib inhibited MET signaling, demonstrated marked regression of METex14 del-driven patient-derived xenografts, and demonstrated a durable RECIST partial response in a METex14 del mutation-positive patient enrolled on a glesatinib clinical trial. Prolonged treatment of nonclinical models with selected MET inhibitors resulted in differences in resistance kinetics and mutations within the MET activation loop (i.e., D1228N, Y1230C/H) that conferred resistance to type I MET inhibitors, but remained sensitive to glesatinib. In vivo models exhibiting METex14 del/A-loop double mutations and resistance to type I inhibitors exhibited a marked response to glesatinib. Finally, a METex14 del mutation-positive NSCLC patient who responded to crizotinib but later relapsed, demonstrated a mixed response to glesatinib including reduction in size of a MET Y1230H mutation-positive liver metastasis and concurrent loss of detection of this mutation in plasma DNA.Conclusions: Together, these data demonstrate that glesatinib exhibits a distinct mechanism of target inhibition and can overcome resistance to type I MET inhibitors. Clin Cancer Res; 23(21); 6661-72. ©2017 AACR.