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T. Zhang



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    Poster Session (ID 8)

    • Event: ACLC 2018
    • Type: Poster Session
    • Track:
    • Presentations: 4
    • Moderators:
    • Coordinates: 11/07/2018, 00:00 - 00:00, Poster Hall
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      P011 - Concurrent ALK/EGFR Alterations in Chinese Lung Cancers: Frequency, Clinical Features, and Differential Response to Therapy (ID 152)

      00:00 - 00:00  |  Author(s): T. Zhang

      • Abstract

      Background:
      ALK rearrangement and EGFR alterations are oncogenic driver mutations in lung cancers. Generally considered mutually exclusive, some studies suggested that these two mutations might occur concomitantly. Limited studies have reported the underlying association of molecular features and drug response to EGFR-TKIs in lung cancers with such co-alterations. Here, we performed next-generation sequencing (NGS) analysis in Chinese lung cancer patients, and evaluated distinct features of EML4- vs. non-EML4-ALK fusions in EGFR-mutated cases.


      Method:
      A retrospective review was performed on genomic profiling data from either tissue or plasma of 419 ALK-rearranged lung cancer patients, sequenced in a CLIA-certified laboratory from 2015 to 2017. Patient characteristics (n=21) and clinical outcomes of patients harboring concurrent EGFR and ALK alterations were collected.


      Results:
      Among the 419 ALK-rearranged lung cancers, a total of 21 patients (5.01%) were detected harboring concurrent ALK and EGFR (exon 18-20) genomic alterations. The concomitant rate of EGFR in patients harboring EML4-ALK (3.06%, 11/359) was dramatically lower than in non-EML4-ALK patients (16.67%, 10/60, p<0.001). Four EML4-ALK and 1 non-EML4-ALK patients were found to have de novo ALK/EGFR co-mutations whereas 1 EML4-ALK and 3 non-EML4-ALK patients acquired their ALK alterations after EGFR TKI treatment. For dual-positive patients who received past EGFR-TKI with unknown ALK status before the treatment, EML4-ALK/EGFR patients (n=6) commonly had shorter PFS to EGFR-TKI as well as higher relative ALK/EGFR allele frequency compared to non-EML4-ALK/EGFR (n=6; mPFS, 5.45 vs 15 months, p=0.11; mRAF, 1.52 vs 0.41, p=0.01), suggesting that EML4-ALK was more likely to be de novo whereas non-EML4-ALK acquired after EGFR-TKI. In addition, we found that for 9 dual-positive patients who had prior first-generation EGFR-TKI treatment, the clinical efficacy of single TKI use varied greatly, and patients might benefit from combination therapy of ALK+EGFR TKIs.


      Conclusion:
      This study revealed that EML4-ALK/EGFR and non-EML4-ALK/EGFR co-alterations displayed distinct prevalence in Chinese lung cancer patients. Our analyses suggested that non-EML4-ALK might be an acquired gene alteration and function as a resistance mechanism to EGFR-TKI, which might explain the observed discrepancy in prevalence as our sequencing cohort consisted of both previously treated or untreated patients. In addition, we observed that patients with dual ALK/EGFR alterations may benefit from combinatorial TKIs therapy.

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      P020 - Characterization of Met Exon 14 Skipping and Association with Clinical Outcomes of Crizotinib in Chinese Lung Cancers (ID 192)

      00:00 - 00:00  |  Author(s): T. Zhang

      • Abstract

      Background:
      Mesenchymal-to-epithelia transition (MET) exon 14 skipping (METex14) has been recognized as a potential driver alteration in lung cancers, and represents an emerging molecular target for lung cancer treatment. However, most studies about patient characterization and clinical outcomes of METex14-positive lung cancer were conducted in Caucasians, relevant data in Chinese patients were lacking. Here, we retrospectively characterized the clinical and molecular features of patients harboring MET mutations causing exon 14 skipping in a large cohort of Chinese lung cancers, and interrogated relevant clinical parameters associated with clinical outcomes of crizotinib treatment.


      Method:
      Genomic profiling data obtained from either plasma or tissue of 7,507 lung cancer patients with various histological types were screened to identify patients harboring METex14.


      Results:
      A total of 68 patients (0.91%), different from the frequency of Western population (3%), were identified to carry DNA alterations predicted to cause METex14 with a median age of 67.5, which is statistically significantly older than the whole cohort (p<0.001, t-test). In addition, METex14 has a female predominance (p=0.036, Fisher

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      P076 - A Lung Adenocarcinoma with Concomitant EGFR And De Novo MET Amplification Response Well to Combination of TKI And Bevacizumab (ID 193)

      00:00 - 00:00  |  Author(s): T. Zhang

      • Abstract

      Background:
      Patients with NSCLC who are carrying concomitant de novo EGFR and MET amplification were commonly reported to have poor response to therapy. Here, we presented a case of a patient harboring concomitant de novo MET and EGFR, who obtained favorable response to combinatorial therapy of TKI and bevacizumab.


      Method:
      We presented a lung adenocarcinoma patient harboring dual EGFR-MET alterations, and evaluated his response to combinatorial therapy of TKI and bevacizumab. In vitro experiments were performed in HCC827(EGFR-19del) and HCC827-GR (EGFR-19del+MET amplification) cells to validate the effect of bevacizumab on MET pathway.


      Results:
      A 44-year-old male stage IV lung adenocarcinoma with left lung tumor was detected harboring of EGFR-19del and MET amplification using PCR and FISH. The patient was treated with erlotinib+bevacizumab and achieved partial response (PR) with a PFS with 13 months. After PD, NGS performed on both tissue and plasma biopsies revealed that the patients obtained first-generation resistant mutation EGFR-T790M, concomitant with EGFR-19del. The patient was treated with osimertinib+bevacizumab and achieved PR. He developed PD again with a PFS of 10.2 months, and repeated biopsies sequencing identified concomitant EGFR-19del and MET amplification. Then, the patient was treated with crizotinib+bevacizumab and the best curative effect was stable disease. Four months later, he developed PD and the third biopsy still revealed positive EGFR-19del and MET amplification. The patient received osimertinib+crizotinib+bevacizumab and he achieved PR one month after treatment initiation. He is still under the treatment and the PFS is more than eight months. In vitro data revealed that, under gefitinib treatment, cell viability was higher in HCC827(EGFR-19del) than HCC827-GR (EGFR-19del+METamp). However, the patient harboring dual EGFR-MET alterations in this study obtained a PFS of 13 months to erlotinib, similar with patients with EGFR-19del only (mPFS was 13 months to erlotinib as reported), suggesting the efficacious treatment of EGFR-TKI and bevacizumab than TKI alone. We observed that VEGFR-2 was expressed at relatively high levels in HCC827-GR than other cell line without METamp, and VEGF pathway inhibition by bevacizumab resulted in decreased phospho-c-Met in HCC827-GR cell lines. This result provided in vitro evidence that bevacizumab can reduce MET pathway activation.


      Conclusion:
      This study provided basic knowledge and evidence for patients harboring concomitant EGFR and de novo MET amplification who may obtain favorable response to combinatorial treatment of TKI and bevacizumab. Encouraging antitumor activity of TKI+bevacizumab support further development of this combination for patients with advanced NSCLC and other solid tumors.

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      P081 - Clinical Characteristics and Molecular Patterns Of RET-Rearranged Lung Cancer in Chinese Patients (ID 191)

      00:00 - 00:00  |  Author(s): T. Zhang

      • Abstract

      Background:
      Rearrangement of RET is identified as an oncogenic alteration in lung cancer. However, studies about characteristics of RET rearrangement in lung cancers are still limited, and several reports were conflicting. Our aim was to demonstrate the clinical and molecular features of RET rearrangement in Chinese lung cancers.


      Method:
      We reviewed genomic profiling data of biopsies (including either tissue or plasma) from 6125 lung cancer patients sequenced in a CLIA-certified laboratory from 2015 to 2017. Patient characteristics, including age, gender and histology classification were collected.


      Results:
      A total of 106 RET rearrangements in 84 patients (1.37%, 84/6125) were identified. RET rearrangement had a tendency to occur in female, adenocarcinoma, with a median age of 58 years. KIF5B-RET fusion was the most frequently occurred subtypes, identified in 53.8% (57/106) RET rearrangements and 67.9% (57/84) of patients, followed by CCDC6-RET and NCOA4-RET. Besides, several rare and novel RET fusion partners were identified, to the best of our knowledge, including TSSK4, SORBS1, SIRT1, PTPRK, ADD3-AS1, PRKG1, IL2RA, CCNYL2, CCDC186 and ANKS1B. We further investigated the concurrent and exclusive genomic alterations in RET-rearranged patients. TP53 was the most commonly seen concurrent mutation, occurring in 42.5% (20/47) of patients, which was followed by EGFR (14.9%, 7/47). KIF5B-RET subtype was fully mutual exclusive with EGFR mutation, suggesting that KIF5B-RET was a strong oncogenic driver mutation. RET fusion partners of the 7 patients harboring concurrent EGFR and RET rearrangement were all non-KIF5B. In addition, we observed that allelic fraction of first-generation EGFR-TKI sensitizing mutation was higher than non-KIF5B-RET in each individual patient, indicating that non-KIF5B-RET fusion might function as a potential acquired resistance mechanism to EGFR tyrosine kinase inhibitors. Clinical outcomes of cabozantinib, a RET kinase inhibitor, were available in six patients with RET-rearrangement, and the median treatment period of cabozantinib for these patients was 5 months. A stage IV adenocarcinoma patient developed resistance to osimertinib and followed NGS revealed that he harbored concurrent CCNYL2-RET fusion and EGFR mutation. After the combinatorial treatment of osimertinib and cabozantinib, he achieved stable disease (SD) with a PFS of 5 months before disease progression.


      Conclusion:
      Lung cancer patients with RET-rearrangement displayed identifiable clinical characteristics and heterogeneous molecular distribution. The investigation of clinical and molecular pattern of RET-rearrangements might be helpful to provide basic knowledge for personalized diagnosis and clinical considerations. Further investigations are needed in the fields of potential sensitivities among different fusion variants and resistance mechanism to RET inhibition.