...he was transitioned to oral osimertinib 80 mg daily in combination with oral savolitinib 300 mg daily under the clinical trial TATTON...he achieved partial response for 18 months before developing progressive disease (Fig. 1). Tissue biopsy confirmed adenocarcinoma, and next-generation sequencing of circulating tumor DNA (FoundationOne Liquid, Foundation Medicine) revealed EGFR-delL747_T751 mutation (allele frequency [AF] 3.3%), lack of EGFR-T790M and EGFR-C797S, MET amplification, and MET mutations (D1228H AF 15.6%, D1228N AF 1.8%, D1228Y AF 1.6%, and Y1230C AF 0.98%).