Crizotinib with or without an EGFR-TKI in treating EGFR-mutant NSCLC patients with acquired MET amplification after failure of EGFR-TKI therapy: a multicenter retrospective study

BackgroundMET amplification is associated with acquired resistance to first-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in treating non-small-cell lung cancer (NSCLC); however, the therapeutic strategy in these patients is undefined. Herein we report the clinical outcomes of patients with c-MET amplification resistance to EGFR-TKIs treated with crizotinib.MethodsWe retrospectively analyzed advanced NSCLC patients from five sites who were diagnosed with EGFR-mutant NSCLC and received EGFR-TKI treatment. After disease progression, these patients were confirmed to have a MET-to-centromere ratio (MET:CEN)1.8 based on fluorescence in situ hybridization (FISH) examination and without a T790M mutation. We assessed the efficacy and safety of crizotinib to overcome EGFR-TKI resistance in EGFR-activating mutations NSCLC with acquired MET amplification.ResultsAmplification of the acquired MET gene was identified in 18 patients with EGFR-mutant NSCLC. Fourteen patients received crizotinib treatment after acquired resistance to EGFR-TKIs. Among the 14 patients, 6 (42.9%) received crizotinib plus EGFR-TKI and 8 (57.1%) received crizotinib monotherapy. The overall objective response rate (ORR) and disease control rate (DCR) were 50.0% (7/14) and 85.7% (12/14), respectively. The median PFS (mPFS) of patients receiving crizotinib monotherapy and crizotinib plus EGFR-TKI was 6.0 and 12.6months, respectively (P=0.315). Notably, treatment efficacy was more pronounced in patients with crizotinib than patients with chemotherapy (24.0months vs. 12.0months, P=0.046). The mOS for 8 of 14 patients receiving crizotinib monotherapy and 6 of 14 patients receiving crizotinib plus EGFR-TKI was 17.2 and 24.0months, respectively (P=0.862). Among the 14 patients, 1 who received crizotinib monotherapy (grade 3 nausea) and 2 who received crizotinib plus EGFR-TKI (grade 3 elevated liver aminotransferase levels) received reduced doses of crizotinib (200mg twice daily) to better tolerate the dose.ConclusionsWe observed the clinical evidence of efficacy generated by combination of crizotinib and previous EGFR-TKIs after the resistance to first-generation EGFR-TKIs. These results might increase evidence of more effective therapeutic strategies for NSCLC treatment. Combination therapy did not increase the frequency of adverse reactions.