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V. Melnikova
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MA08 - Treatment Monitoring in Advanced NSCLC (ID 386)
- Event: WCLC 2016
- Type: Mini Oral Session
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:R. Perez-Soler, T. Reungwetwattana
- Coordinates: 12/06/2016, 11:00 - 12:30, Lehar 3-4
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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 - 11:06 | Author(s): V. Melnikova
- Abstract
- Presentation
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
- Moderators:
- Coordinates: 12/07/2016, 14:30 - 15:45, Hall B (Poster Area)
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P3.02b-024 - Dynamics of EGFR Mutational Load in Urine and Plasma Correlates with Treatment Response in Advanced NSCLC (ID 5529)
14:30 - 14:30 | Author(s): V. Melnikova
- Abstract
Background:
NSCLC is a heterogeneous and dynamic disease where testing for key mutations is essential. With the emergence of clonal resistance, obtaining serial biopsies to assist in the real-time treatment decision-making has proven challenging. Molecular assessments of circulating tumor (ct)DNA has been previously shown feasible utilizing blood specimens. Here we additionally investigated the utility of serial urine ctDNA analysis in NSCLC.
Methods:
This is a prospective observational study of patients with non-squamous, tissue-confirmed EGFR, KRAS or ALK mutant NSCLC preparing to receive a systemic treatment regimen. Urine and blood specimens were collected at baseline, on treatment and at progression for ctDNA analyses. The primary endpoints were correlation between ctDNA and tumor-based molecular results, and measurable change in ctDNA with response by RECIST v1.1. Blood and urine samples were sent to Trovagene for DNA extraction and mutation enrichment NGS.
Results:
Of the 34 patients enrolled thus far, interim blinded analysis of EGFR activating mutations (L858R, exon 19 deletions) was conducted in 20 patients with EGFR-positive tumors. Of 20 patients, 17 (85%) had detectable concordant EGFR mutation in pre-treatment urine and/or plasma. Of 11 patients with matched serial ctDNA samples, detectable EGFR mutation signal was observed in pre-treatment urine and/or plasma of 9 patients. These 9 patients received first to sixth line treatment with single EGFR TKI (n=3), combination TKIs (n=3), chemotherapy (n=1), immune checkpoint inhibitors alone (n=1) or in combination with TKI (n=1). In 9 of 9 patients, changes in ctDNA levels from baseline to cycle 2 day 1 on therapy correlated with best response to treatment: a 100% decrease in urine and plasma EGFR mutation levels was observed in 6 of 6 patients with partial response (PR, n=3) or stable disease (SD, n=3), while less than a 90% decrease or an increase in urine and plasma EGFR levels was observed in patients with progressive disease (PD, n=3).
Conclusion:
Mutation enrichment NGS testing by urine and plasma ctDNA correctly identified EGFR activating mutations in 85% of patients. Monitoring EGFR levels in urine/plasma enabled accurate assessment of response in advance of radiographic evaluation and regardless of therapy type in 100% of patients, with cut-point of a 90% decrease in EGFR load discriminating between patients with disease control (PR or SD) and patients with progressive disease. With continued enrollment, our study aims to further investigate clinical utility of urine and plasma ctDNA for early detection of resistance and discontinuation of inefficient therapy.
