Successful crizotinib monotherapy in EGFR-mutant lung adenocarcinoma with acquired MET amplification after erlotinib therapy

MET is a driver oncogene in non-small-cell lung cancer (NSCLC), and its amplification is associated with acquired resistance to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors. A 56-year-old Japanese male with lung adenocarcinoma harboring an EGFR exon 21 L858R mutation received erlotinib to which he responded for 12 months. After disease progression, re-biopsy analyses revealed newly developed MET amplification. Neither EGFR exon 20 T790M mutation nor MET exon 14 mutations were detected. The MET inhibitor, crizotinib, showed a dramatic response. This is the first report of successful crizotinib single-agent therapy in EGFR-mutant NSCLC that acquired MET amplification during erlotinib therapy.