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OA 10 - Liquid Biopsy for Genomic Alterations (ID 678)
- Event: WCLC 2017
- Type: Oral
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:Adrian G. Sacher, Pasi A Jänne
- Coordinates: 10/18/2017, 11:00 - 12:30, F201 + F202 (Annex Hall)
OA 10.03 - Liquid Biopsy in the Lung Cancer Clinic: A Prospective Study of Plasma DNA next Generation Sequencing to Guide Matched Therapy (ID 8218)
11:00 - 12:30 | Author(s): A. Ni
Liquid biopsy for plasma circulating tumor DNA (ctDNA) next generation sequencing (NGS) is now commercially available and increasingly adopted in clinical practice with a paucity of evidence based guidance. We set out to prospectively determine the utility of plasma ctDNA NGS in the lung cancer clinic.
Patients (pts) with advanced NSCLC who were driver unknown or resistance mechanism unknown were eligible. Pts were enrolled prospectively at Memorial Sloan Kettering (NY, USA) and Northern Cancer Institute (Sydney, Australia). Peripheral blood was collected in Streck tubes (10-20mL) and sent to Resolution Bioscience (Bellevue, WA) for targeted NGS of extracted DNA using a bias corrected hybrid capture 21 gene assay in a CLIA laboratory with unique reads at 3000x and sensitive detection at variant allele frequency above 0.1%. Clinical endpoints included detection of oncogenic drivers, turnaround time, comparison to tissue NGS when available, and ability to match pts to targeted therapy along with their treatment outcomes.
Seventy-six pts were prospectively accrued. Plasma NGS detected an oncogenic driver in 36% (27/76) of pts, of whom 14% (11/76) were matched to targeted therapy; including pts matched to clinical trials for HER2 exon 20 insYVMA, BRAF L597Q and MET exon14. Of the 10 evaluable pts, 10 partial responses were observed. Mean turnaround time for plasma was 6 days (3-12) vs 21 days (16-30) for tissue (P <0.0001). Plasma ctDNA was detected in 60% (46/76) of pts; detection rate was 46% (16/35) if blood was drawn on active therapy and 73% (30/41) if drawn off therapy, either at diagnosis or progression (Odds ratio 0.31, 95% CI 0.12 – 0.81; P=0.02). Of the 25 concurrent tissue NGS performed to date, there was a 96% plasma concordance with tissue and a 60% tissue concordance with plasma for driver mutations.
In pts who were driver or resistance mechanism unknown, plasma NGS identified a variety of oncogenic drivers with significantly shorter turnaround time compared to tissue NGS, and matched patients onto targeted therapy with clinical benefit. Plasma ctDNA is best detected at diagnosis of metastatic disease or at progression. A positive finding of an oncogenic driver in plasma is highly specific and can immediately guide treatment, but a negative finding may still require tissue biopsy. Our findings provide evidence to support the incorporation of plasma NGS into practice guidelines.
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