The comparison of chemotherapy and treatments according to NGS results in advanced lung adenocarcinoma patients resistant to EGFR-TKIs.

e21082 Background: There were no relative researches referring to optimal treatment strategy after the resistance to the first/second-generation EGFR-TKIs without T790M mutation or the third generation EGFR-TKIs as the first or second line therapy. Methods: Retrospective analysis was performed on the clinical and sequencing data obtained from 129 patients with advanced EGFR-mutant lung adenocarcinoma and disease progression on the prior EGFR-TKIs.The patients were divided into Chemotherapy group or Personalized group according the the therapies after acquired resistance to EGFR-TKIs. Results: 36 patients were enrolled in Personalized group and 93 in Chemotherapy group. Personalized group：22 patients with MET amplification received the combination therapy of EGFR-TKIs and MET inhibitors; 6 patients with SCLC transformation received EP/EC chemotherapy; 2 patients with BRAF mutation were treated with the combination of EGFR-TKIs, dabrafenib and trametinib; 3 patients with ERBB2 amplification were added Trastuzumab in the therapy; 2 patients with RET fusion were accepted LOXO-292 therapy; 1 patient had the combination therapy of the 1st and 3rd EGFR-TKIs because of T790m and C797S mutations in trans allelic context.Chemotherapy group: 79 patients received pemetrexed plus platinum therapy, 14 patients received paclitaxel plus platinum therapy. 12 patients achieved PR and 11 patients achieved SD in Personalized group, 48 PR, 25 SD in Chemotherapy group. The median PFS was 5.5 months in Chemotherapy group and 3.5 months in Personalized group, No significant differences were observed in ORR(p = 0.13), DCR(p = 0.12) and PFS(P = 0.26) between two group. Conclusions: Chemotherapy maybe is the optimal choice to patients with advanced EGFR-mutant lung adenocarcinoma and disease progression on the prior EGFR-TKI in current medical conditions.