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P1.01 - Advanced NSCLC (ID 757)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Advanced NSCLC
- Presentations: 1
- Coordinates: 10/16/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
P1.01-040 - Clinical Utility of Plasma-Based NGS for Advanced-Stage NSCLC Patients with Insufficient or Unavailable Tumor Tissue (ID 10215)
09:30 - 16:00 | Author(s): M. Palka
The failure rate of tissue-based NGS in newly diagnosed NSCLCs is approximately 20-25 %, reaching 40 % in the case of tumor biopsy samples collected at disease progression. In this study, we are analyzing the clinical utility of plasma-based NGS using cell-free circulating tumor DNA (ctDNA) for advanced-stage lung adenocarcinoma patients, as a complement or alternative to tissue-based molecular profiling.
Eight Academic Spanish Institutions are participating in patient recruitment. We are stratifying patients in three cohorts: 1) Patients with advanced-stage lung adenocarcinomas with insufficient tumor tissue for EGFR, ALK or ROS1 analysis; 2) Patients with EGFR, ALK or ROS1 altered tumors with acquired TKI resistance; 3) Patients with EGFR T790M positive cancers progressing on third generation EGFR TKIs. Next-generation ctDNA sequencing is being performed using GUARDANT360 73-gene panel at a CLIA certified central laboratory facility (Redwood City, California). We are stratifying gene variant actionability into four levels according to the OncoKB website criteria.
We have currently included 97 patients (January-June 2017). Complete clinical and molecular data are available at present for the first 37 patients. Twelve, 19 and 6 patients have been enrolled in cohorts 1, 2 and 3 respectively. Never smoker patients were overrepresented (n = 21, 56 %), predominantly at cohorts 2 and 3. A total of 30 cases (81 %) had detectable ctDNA. We have detected potentially actionable genetic alterations involved in mitogenic pathways in 16 patients (43 %). Level 1 alterations (variants with matched approved drugs) were found in three patients’ tumors (25 %) from cohort 1 (two EGFR sensitizing mutations and one ROS1 rearrangement). Nine patients (36 %) from cohort 2 and 3 had tumors with potentially targetable acquired genetic alterations, including three cases with EGFR T790M mutations and one case with a ROS1 kinase domain mutation. Six patients (16 %) received matched targeted therapies, four (11 %) in genotype-driven clinical trials. Reasons for not receiving matched targeted therapies in patients with actionable tumors were clinical deterioration or death (n = 2), unavailability of matched clinical trials (n = 6), treatment with non-genotype-tailored therapies (n =1) or no disease progression to ongoing therapies (n =1). Final clinical and molecular data of the whole cohort will be provided at the meeting.
On the basis of our preliminary data, next-generation ctDNA sequencing (GUARDANT 360) appears to detect actionable genetic alterations when tissue is unavailable, avoiding multiple biopsies and enabling rapid patient selection for genotype-tailored therapies.
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