Osimertinib combined with savolitinib in the treatment of EGFR mutated osimertinib resistant NSCLC with low copy number MET amplification There are unmet medical needs in patients who resist to to osimertinib; savolitinib plus osimertinib shows high response rate and prolong progression-free survival in high copy number MET amplification patients. This study is to explore the efficacy and safety of the combination of savolitinib and osimertinib in osimertinb resistant patients with low copy number MET amplification.