Activating Mutations in the MET Kinase Domain Co-Occur With Other Driver Oncogenes and Mediate Resistance to Targeted Therapy in NSCLC.

Introduction: MET tyrosine kinase domain (TKD) mutations have recently been characterized as de novo oncogenic drivers in NSCLC. Nevertheless, whether activating MET TKD mutations can confer resistance to targeted therapy in non-MET, oncogene-driven NSCLCs remains unclear.

Methods: To characterize the genomic features of tumors with MET TKD mutations in oncogene-driven NSCLC, we performed tumor genomic profiling on two different cohorts of patients with NSCLC. Preclinical models of the most frequently observed MET TKD mutations were generated to determine the effect on sensitivity to targeted therapy. Treatment strategies to overcome MET TKD mutation-mediated resistance were further explored.

Results: Genomic profiling of more than 115,000 patients with NSCLC found that activating MET TKD mutations are prevalent in 0.15% of cases, and that about half of them co-occur with another oncogenic driver, with a differential pattern in co-occurring MET TKD mutations according to the oncogenic alteration. A review of eight cases with sequential genomic testing revealed that the MET TKD mutation was acquired after systemic therapy in 88% of cases, with a potential contribution of APOBEC mutagenesis underlying this process. In vitro, MET TKD mutation conferred resistance to targeted therapy in diverse oncogene-driven models, which could be overcome by combinatorial treatment against both the primary oncogene and the MET TKD mutation.

Conclusions: MET TKD mutation can act as an off-target resistance mechanism in diverse oncogene-driven NSCLC. Combination therapy with an effective MET-targeted therapy can potentially overcome MET TKD mutation-mediated resistance.