OBJECTIVE: To compare the efficacy and average daily medical cost of osimertinib and chemotherapy in posterior-line treatment for patients with non-small cell lung cancer（NSCLC）

and to investigate the application of osimertinib in patients with EGFR T790M-positive NSCLC

so as to provide evidence-based medical evidence for osimertinib. METHODS: Retrospective analysis on 339 patients with NSCLC who progressed through the first generation of EGFR-TKI treatment in the department of respiratory and critical care medicine of this hospital from 2014 to 2020

which were divided into osimertinib group

chemotherapy group and other treatment group according to different treatment regimens

the efficacy and health economics analyses were performed by using Graphpad and SPSS software. RESULTS: In terms of efficacy

patients in the osimertinib group had significantly longer progression-free survival（11.4 months vs. 4.0 months

P<0.000 1） than that in the chemotherapy group and significantly longer overall survival（36.60 months vs. 25.95 months vs. 16.83 months

P<0.000 1） than that in the chemotherapy group and the other treatment groups. Comparing the average daily medical costs

patients in the osimertinib group were significantly lower than that in the chemotherapy group（80.86 yuan vs. 150.32 yuan

U=1 947.000

P<0.000 1）

all differences were statistically significant. CONCLUSIONS: For T790M-positive NSCLC patients who have progressed through the first generation of EGFR-TKI treatment

osimertinib may be an efficient

low-toxic and cost-effective option as a posterior-line treatment.