Emergence of Preexisting MET Y1230C Mutation as a Resistance Mechanism to Crizotinib in NSCLC with MET Exon 14 Skipping.

INTRODUCTION: MET proto-oncogene, receptor tyrosine kinase gene exon 14 skipping (METex14) alterations represent a unique subset of oncogenic drivers in NSCLC. Preliminary clinical activity of crizotinib against METex14-positive NSCLC has been reported. The full spectrum of resistance mechanisms to crizotinib in METex14-positive NSCLC remains to be identified.

METHODS: Hybrid capture-based comprehensive genomic profiling performed on a tumor specimen obtained at diagnosis, and a hybrid capture-based assay of circulating tumor DNA (ctDNA) at the time of progression during crizotinib treatment was assessed in a pairwise fashion.

RESULTS: A METex14 alteration (D1010H) was detected in the pretreatment tumor biopsy specimen, as was MET proto-oncogene, receptor tyrosine kinase (MET) Y1230C, retrospectively, at very low frequency (0.3%). After a confirmed response during crizotinib treatment for 13 months followed by progression, both MET proto-oncogene, receptor tyrosine kinase gene Y1230C and D1010H were detected prospectively in the ctDNA.

CONCLUSION: Emergence of the preexisting MET Y1230C likely confers resistance to crizotinib in this case of METex14-positive NSCLC. Existence of pretreatment MET Y1230C may eventually modulate the response of METex14-positive NSCLC to type I MET tyrosine kinase inhibitors. Noninvasive plasma-based ctDNA assays can provide a convenient method to detect resistance mutations in patients with previously known driver mutations.