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J. Zhao



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    MA 11 - Emerging Diagnostic/Biomarkers in NSCLC (ID 668)

    • Event: WCLC 2017
    • Type: Mini Oral
    • Track: Advanced NSCLC
    • Presentations: 1
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      MA 11.07 - Exosomes-Transmitted MicroRNAs Promote EGFR-TKIs Resistance in NSCLC by Activating PI3K/AKT Signaling Pathway (ID 9446)

      11:00 - 12:30  |  Author(s): J. Zhao

      • Abstract
      • Presentation
      • Slides

      Background:
      Acquired epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) resistance is a major factor contributing to targeted therapy failure in EGFR mutant non-small cell lung cancer (NSCLC), among which T790M mutation accounts for 50-60%. Emerging evidence has shown that as mediators between cells, exosomes shed by drug resistant cancer cells have the ability to horizontally transfer drug resistant phenotype to drug sensitive cells, which has been described as an important mechanism of dissemination of drug resistance. However, whether exosomes derived from EGFR-TKIs resistant NSCLC cells harboring T790M mutation could transfer resistance to sensitive cells has not been understood and the potential mechanism also remains unknown.

      Method:
      Exosomes were isolated from supernatants of T790M mutant NSCLC cell line (H1975) and characterized by transmission electron microscopy, nanosight and western blot. Their potential roles in mediating gefitinib resistance in sensitive cell line (PC9) were investigated in vitro and in vivo. Cell viability and the effects of exosomes on downstream signaling pathways were analyzed by CCK-8 assays and western blot. The roles of exosomes in regulating gefitinib resistance in vivo were assessed by subcutaneous transplantation tumor model in athymic nude mice. Exosomes miRNA sequencing and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) were used for exploring the underlying mechanism.

      Result:
      Exosomes isolated from conditioned medium of NSCLC cell lines were cup-shaped membranous vesicles with a diameter of 30-100 nm and expressed the exosomal marker CD63. Exosomes derived from H1975 could transmit gefitinib resistance to PC9 (P<0.01) in vitro while exosomes released from PC9 cell don’t have this effect. Treatment of PC9 with H1975-derived exosomes and the inhibitor of exosomes production (GW4869) could restore gefitinib response. In vivo, the tumor volume of xenograft model of PC9 cells treated with gefitinib plus H1975-derived exosomes was significantly larger than those mice treated with gefitinib alone (P<0.05). Furthermore, H1975 xenografts could disseminate gefitinib resistance to PC9 xenografts in the same mice. This difference disappeared by the addition of GW4869. Mechanistically, intercellular transfer of microRNAs (miR-522-3p and miR-454-3p) by exosomes disseminated gefitinib resistance through activating PI3K/AKT and MEK/ERK signaling pathways

      Conclusion:
      Our findings demonstrate that EGFR-TKIs resistant cells could disseminate drug resistance to sensitive cells by intercellular transfer of exosome-transmitted microRNAs and then activating PI3K/AKT and MEK/ERK signaling pathways, which reveals a novel mechanism of acquired resistance to EGFR-TKIs in NSCLC.

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    P1.03 - Chemotherapy/Targeted Therapy (ID 689)

    • Event: WCLC 2017
    • Type: Poster Session with Presenters Present
    • Track: Chemotherapy/Targeted Therapy
    • Presentations: 1
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      P1.03-052 - Comparing EGFR-TKI with EGFR-TKI plus Chemotherapy as 1st Line Treatment in Advanced NSCLC Patients with Both Mutated EGFR and Bim Polymorphism (ID 10516)

      09:30 - 16:00  |  Author(s): J. Zhao

      • Abstract
      • Slides

      Background:
      Not all advanced non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) activating mutations could get benefit from 1[st] line treatment of EGFR tyrosine kinase inhibitors (TKIs). Our previous study indicated that B-cell chronic lymphocytic leukemia/lymphoma-like 11 (Bim) deletion polymorphism was about 10% and was significantly associated with a poor clinical response to EGFR-TKIs in EGFR mutation-positive NSCLC. This retrospective study compared efficacy and tolerability of the EGFR-TKI alone versus EGFR-TKI plus chemotherapy as the 1[st] line treatment in advanced NSCLC patients with both activated EGFR mutation and Bim polymorphism.

      Method:
      Main included criterias were patients older than 18 years, histologically confirmed stage IIIB or IV NSCLC, EGFR mutation-positive (exon 19 deletion or 21 L858R mutation) and Bim polymorphism. Patients received gefitinib 250mg orally a day or gefitinib together with up to 4 cycles of pemetrexed/gemcitabine and platinum until disease progression or unacceptable toxic effects. The primary endpoint was progression-free survival (PFS); the second endpoint included objective response rate (ORR), overall survival (OS) and toxicity.

      Result:
      From June 2014 to September 2016, 65 patients were enrolled into this trial. 36 of them received gefitinib, and 29 received gefitinib plus pemetrexed/gemcitabine and platinum. Median PFS was significantly longer in EGFR-TKI plus chemotherapy-treated patients than in EGFR-TKI (7.2 [95% CI 5.35-9.05] vs 4.6 [4.01-5.19] months; p=0.008). The ORR was significantly lower in EGFR-TKI than in EGFR-TKI plus chemotherapy-treated patients (38.9% vs. 65.5% p=0.046). EGFR-TKI plus chemotherapy was associated with more grade 3 or 4 hematological toxic effects than EGFR-TKI (8 neutropenia, 4 thrombocytopenia vs. no any event). Figure 1



      Conclusion:
      Compared with EGFR-TKI, EGFR-TKI plus chemotherapy conferred a significant higher ORR and longer PFS in advanced NSCLC patients with both activated EGFR mutation and Bim polymorphism. An open-label, multicenter, randomized, phase 2 study is ongoing to validate these results in our institute ( NCT03002844).

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    P1.15 - SCLC/Neuroendocrine Tumors (ID 701)

    • Event: WCLC 2017
    • Type: Poster Session with Presenters Present
    • Track: SCLC/Neuroendocrine Tumors
    • Presentations: 1
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      P1.15-009 - Safety and Efficacy of Nab-Paclitaxel Monotherapy as 2nd or Later Line Setting in Pts with Extensive SCLC, a Phase II Single Arm Study (NCT02262897) (ID 9583)

      09:30 - 16:00  |  Author(s): J. Zhao

      • Abstract

      Background:
      There is still an unmet need for patients with extensive small cell lung cancer(SCLC) who failed from the previous treatment even though topotecan was approved by Food and Drug Administration as second line setting in this population. Nab-paclitaxel (nab-P) has showed promising efficacy in pancreas cancer, breast cancer and nonsmall cell lung cancer, this phase II trial try to evaluate the safety and efficacy of nab-paclitaxel (nab-P) monotherapy as the secondary or later line therapy in patients with extensive SCLC.

      Method:
      Main included criteria were performance status 0-2, extensive disease, failed or insensitive relapse from the previous treatment, sufficient myeloid function. Sensitive relapsed from the last line chemotherapy was excluded. Patients who met these criteria received weekly nab-paclitaxel 130mg/m2, d1,8,15, every 4 week or nab-paclitaxel of 230 mg/m2, d1 every 3 weeks. The Primary end point is objective response rate. The secondary end point included progression free survival(PFS), overall survival, and side effects.

      Result:
      From Sep, 2014 to Mar, 2017, 40 patients were included into this study, included 39 males, 6 never smokers, PS 1/2:27/13 with a median age of 66 years. The median line of nab-P monotherapy is 3(2-5). Among them, 30 patients received weekly nab-P and 10 received nab-P every 3 weeks. 9, 27, 4 patients were resistant, refractory and sensitive relapse to first line chemotherapy respectively. 7 patients got partial response,17 stable diseases and 16 progression disease. The objective response rate was 17.5% and disease control rate(DCR) was 60%. The median PFS was 3 months and the during of response was 5.8 months. Subgroup analysis showed that patients who were refractory or sensitive relapse to first line chemotherapy had a significant higher DCR (67.8% vs 28.5%, p=0.042) and longer PFS(3.3 vs 1.4 months, p=0.04), while similar results were found in different PS, smoking status and lines of therapy. Toxicity was mild and manageable including alopecia, neuritis, neutropenia and anemia, no grade 3/4 adverse event observed.

      Conclusion:
      Nab-P showed promising efficacy together with acceptable toxicity in patients with extensive SCLC who failed or insensitive relapse from the previous treatment, especially in the subgroup of refractory or sensitive relapse to first line chemotherapy, large cohort study is needed to validate these findings.