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H. Yu



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    MA08 - Treatment Monitoring in Advanced NSCLC (ID 386)

    • Event: WCLC 2016
    • Type: Mini Oral Session
    • Track: Advanced NSCLC
    • Presentations: 1
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      MA08.01 - A Highly Sensitive Next-Generation Sequencing Platform for Detection of NSCLC EGFR T790M Mutation in Urine and Plasma (ID 4637)

      11:00 - 12:30  |  Author(s): H. Yu

      • Abstract
      • Presentation
      • Slides

      Background:
      Non-invasive genotyping of NSCLC patients by circulating tumor (ct)DNA is a promising alternative to tissue biopsies. However, ctDNA EGFR analysis remains challenging in patients with intrathoracic disease, with a reported 26-57% T790M mutation detection rate in plasma (Karlovich et al., Clin Cancer Res 2016; Wakelee et al., ASCO 2016). We investigated whether a mutation enrichment NGS could improve mutation detection in plasma and urine from TIGER-X, a phase 1/2 study of rociletinib in patients with EGFR mutation-positive advanced NSCLC.

      Methods:
      The therascreen (Qiagen) or cobas (Roche) EGFR test was used for EGFR T790M analysis in tumor biopsies. Urine and plasma were analyzed by trovera mutation enrichment NGS assay (Trovagene).

      Results:
      Of 174 matched tissue, plasma and urine specimens, 145 (83.3%) were T790M+ by central tissue testing, 142 (81.6%) were T790M+ by plasma, and 139 (79.9%) were T790M+ by urine. Urine and plasma combined identified 165 cases (94.8%) as T790M+. Of 25 cases positive by ctDNA but negative/inadequate by tissue, 16 were double-positive in plasma and urine, unlikely to be false positive (Figure 1). T790M detection rate was higher for extrathoracic (n=119) vs intrathoracic (n=55) disease in plasma (87.4% vs 69.1%, p=0.006) but not urine (81.5% vs 76.4%, p=0.42). Combination of urine and plasma identified T790M in 92.7% of intrathoracic and 95.8% of extrathoracic cases (p=0.47). In T790M+ patients, objective response rate was similar whether T790M mutation was identified by tissue, plasma or urine: 37.4%, 33.1% and 36.6%, respectively. 4 of 9 patients T790M+ by urine but negative by tissue responded, and 2 of 8 patients T790M+ by plasma but negative by tissue responded.

      Conclusion:
      Mutation enrichment NGS testing by urine and plasma combined identified 94.8% of T790M+ cases. Combination of urine and plasma may be considered before tissue testing in EGFR TKI resistant NSCLC, including patients without extrathoracic metastases. Figure 1



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    P3.02b - Poster Session with Presenters Present (ID 494)

    • Event: WCLC 2016
    • Type: Poster Presenters Present
    • Track: Advanced NSCLC
    • Presentations: 1
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      P3.02b-115 - Clinical Activity of Osimertinib in EGFR Mutation Positive Non Small Cell Lung Cancer (NSCLC) Patients (Pts) Previously Treated with Rociletinib (ID 4893)

      14:30 - 15:45  |  Author(s): H. Yu

      • Abstract

      Background:
      Both osimertinib and rociletinib were developed to target the EGFR resistance mutation T790M. Sequist, et al reported clinical activity with osimertinib in 9 pts previously treated with rociletinib[1]. We conducted a retrospective analysis at 8 institutions of pts treated with rociletinib, who discontinued the drug due to disease progression or intolerable toxicity and subsequently received osimertinib.

      Methods:
      We identified pts treated with rociletinib followed by osimertinib, as part of osimertinib's US expanded access program or via commercial supply. Clinical characteristics and outcomes were assessed. Frequency of clinical and radiologic assessments on osimertinib was at the discretion of the treating physician. For this retrospective review, reverse KM method was used to calculate the median follow-up; KM method was used for time-to-event endpoints.

      Results:
      45 pts were included in this analysis. Median age at the start of osimertinib was 66 years (43-86) and 71% were female. 28 pts had exon 19 deletions and 16 had L858R. Median duration of therapy on front line EGFR TKI was 18 months (5-54). Median starting dose of rociletinib was 625 mg bid (range 500-1000). The response rate (RR) and disease control rate (DCR; Response+Stable Disease) with rociletinib were 38% and 91%; median duration of rociletinib therapy was 6.2 months. 32 (71%) pts discontinued rociletinib for disease progression. 23 (51%) pts received other therapies (1-4) before starting osimertinib. 25 (56%) pts were known to have brain metastases at osimertinib initiation. RR and DCR with osimertinib were 33% and 82%. DCR in the brain was 88%. With a median follow-up of 7.1 months, median duration of osimertinib therapy in all patients was 8 months (95%CI- 6.6-NR; 64% censored). The 1-year overall survival (OS) rate on osimertinib was 70% (54%-91%). In the 32 pts who discontinued rociletinib due to progression, DCR with osimertinib was 75% and median duration of therapy was 7.8 months (4.6-NR). Neither duration of,or response to rociletinib treatment, nor interval between the two the drugs was associated with duration of osimertinib or OS after osimertinib using a Cox model adjusted for age and sex.

      Conclusion:
      Osimertinib can provide clinical benefit in EGFR mutation positive NSCLC patients previously treated with rociletinib. The clinical activity of osimertinib in these patients may be related to more potent inhibition of T790M mutation or ability to overcome resistance to rociletinib. Reference- 1. Sequist, et al. JAMA Oncology 2016