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Z. Chen



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    P1.01 - Advanced NSCLC (ID 757)

    • Event: WCLC 2017
    • Type: Poster Session with Presenters Present
    • Track: Advanced NSCLC
    • Presentations: 1
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      P1.01-018 - Acquired Resistance to Crizotinib in Advanced NSCLC with De Novo MET Overexpression (ID 10014)

      09:30 - 16:00  |  Author(s): Z. Chen

      • Abstract
      • Slides

      Background:
      MET exon14 skipping mutation has been regarded the driver mutation for MET activation, but with relatively low frequency of occurrence. MET overexpression can be a promising biomarker to predict the response to crizotinib. However, little is known about acquired resistance to treatments in tumors with de novo MET overexpression.

      Method:
      This prospective observational study included 33 NSCLC patients with MET IHC overexpression received crizotinib treatment From January 2013 to June 2017, 23 eligible patients evaluable for response . MET expression level were detected by immunohistochemistry (IHC) with antibody SP44, and ≥50% tumor cells with moderate to high intensity staining were defined as positive. Gene copy numbers were detected by FISH (Met probes from KREATECHTM.), and referring to Cappuzzo scoring system or MET/CEP7 ratio, ≥5 copies were positive or MET/CEP7 ratio ≥1.8 (low ≥1.8-≤2.2, Intermediate >2.2-<5 and High ≥5) was defined as MET amplification;. The status of EGFR, ALK, KRAS and ROS1 were also tested at baseline. Biopsy specimens obtained both at baseline and at the time of progression using targeted next-generation sequencing to assess for mechanisms of resistance.

      Result:
      Response were evaluable for 23 NSCLC patients with MET overexpression (4 female, 19 male). Fifteen of them achieved partial response (PR, 65.2%), 2 were stable disease (SD) and 6 were progressive disease (PD). All responders had high MET expression , and 12(52.2%) with FISH positive. The PFS and OS in the ITT population were 3.2 and 13.2 month respectively. Median PFS was 7.4m(95% CI,4.5-10.4) for MET IHC (100%+++) patients vs. MET IHC (50%++~100%+++) 1.9m (95% CI 0.9-2.9,P=0.053), For FISH positive patients, mPFS was 8.2 m(95% CI,5.2-11.1) m v.s. FISH negative 1.3m(95% CI,0.2-1.7,p=0.002). Two acquired resistance mechanisms were found after resistance, a 64 male patient with MET IHC 100%×3,FISH (+),crizotinib first line and the best response PR, rebiopsy after resistance showed the MET D1228N mutation by NGS, and the second patient was 50 years old male with MET IHC 100%×3,FISH (+),crizotinib first line and the best response was PR, EGFR amplification were found upon progression when rebiopsy after resistance. The patient acheived PR with subsequent treatment of cetuximab plus Taxel.

      Conclusion:
      Multiple mechanisms of acquired resistance to crizotinib were found in de novo MET overexpressed patients. A secondary mutation in the MET gene and EGFR amplification may be the two main mechanisms. MET overexpression could be as a biomarker for de novo MET positive NSCLC. FISH seems better in predicting efficacy for MET inhibitor.

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    P2.03 - Chemotherapy/Targeted Therapy (ID 704)

    • Event: WCLC 2017
    • Type: Poster Session with Presenters Present
    • Track: Chemotherapy/Targeted Therapy
    • Presentations: 1
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      P2.03-054 - EGFR Mutation with Acquired C-MET Positive Reveals Potential Immunotherapeutic Vulnerabilities (ID 10436)

      09:30 - 16:00  |  Author(s): Z. Chen

      • Abstract
      • Slides

      Background:
      There are few effective strategies for C-MET positive advance non-small-cell lung cancer(NSCLC) patients with epidermal growth factor receptor(EGFR) inhibitor resistance.The efficacy of PD-1 blockade immunotherapy and even the status of PD-L1 expression in such population is unclear.

      Method:
      Patients diagnosed as advanced NSCLC synchronously tested for EGFR status, expression of PD-L1 and C-MET at the Guangdong Lung Cancer Institute (GLCI) from 2015 to 2017 were collected.PD-L1 expression on tumor cells and immune cell was evaluated using a three-tiered grading system. C-MET positive was define as immunohistochemistry staining (2+/3+) in ≥ 50% of tumor cells. A chi-squared test was used to assess the relationships between C-MET positive and PD-L1 expression.

      Result:
      A total of 487 eligible cases were selected including 166 EGFR mutant and 321 wild type patients.In the general population(n=487),the difference of PD-L1 expression were observed between C-MET positive group and C-MET negative group (65.3% vs 31.7%, P=0.001),which was in accordance with the result from the Cancer Genome Atlas (TCGA) dataset (n=512,P<0.001).Furthermore,among the EGFR mutant patients (n=166), PD-L1 expression was showed in 58.1% of C-MET positive group and 28.5% of C-MET negative group,P value <0.001. Subsequently,T790M negative was identified in 55%(47/86) of EGFR TKI resistant patients (n=86).In this subgroup,a significant increase of PD-L1 expression was demonstrated in C-MET positive group compared to C-MET negative group(66.7% vs 34.6%,P=0.027).Finally, clinical efficacy of immunotherapy was further confirmed in 2 C-MET positive advanced lung adenocarcinoma patients with remarkable response to PD-1 blockade immunotherapy who had disease progression after C-MET inhibitors.Figure 1



      Conclusion:
      C-MET positive maybe associated with high PD-L1 expression in advanced NSCLC providing therapeutic insight into targeting the PD-1/PD-L1 pathway in EGFR inhibitor-resistant NSCLC with C-MET positive and T790M negative.

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