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S. Zhang
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MA 01 - SCLC: Research Perspectives (ID 650)
- Event: WCLC 2017
- Type: Mini Oral
- Track: SCLC/Neuroendocrine Tumors
- Presentations: 1
- Moderators:John V Heymach, Eun Kyung Cho
- Coordinates: 10/16/2017, 11:00 - 12:30, Room 503
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MA 01.03 - The Potential of ctDNA Sequencing in Disease Monitoring and Depicting Genomic Evolution of Small-Cell Lung Cancer Under Therapy (ID 9682)
11:10 - 11:15 | Author(s): S. Zhang
- Abstract
- Presentation
Background:
Although small cell lung cancer (SCLC) is sensitive to initial therapy, almost all patients relapse and survival remains poor. Outgrowth of treatment-resistant subclones could be responsible for recurrence. However, genomic evolution of SCLC after treatment hasn’t been well investigated, partially due to the challenge of obtaining longitudinal samples. CT is the standard modality for response assessment and disease monitoring. But it doesn’t always accurately assess the disease status. SCLC is characterized by early hemagenous spread, which makes circulating tumor DNA (ctDNA) analysis a promising modality for genomic profiling and disease monitoring of SCLC.
Method:
Targeted-capture deep sequencing (mean target coverage 538x-1866x) of 545 cancer genes was performed to 44 ctDNA samples collected before therapy as baseline and at different timepoints during treatment from 23 SCLC patients. Pretreatment tumor biopsies from 8 patients were also sequenced (mean target coverage 348x-1281x) of the same gene panel. DNA from peripheral blood mononuclear cells was served as the germline control.
Result:
Mutations were identified in all 44 ctDNA samples with a median of 16 mutations per sample (average mutation burden of 6.6/Mb). TP53 and RB1 were the most frequently mutated genes, detected in 91% (21/23) and 65% (15/23) patients, respectively. 74 mutations were identified from the 8 tumor biopsies, among which, 69 (93.2%) were detected in matched ctDNA. We inferred subclonal architecture of each ctDNA sample based on cancer cell fraction derived using PyClone. A median of 10 (ranging 2-26) subclones was inferred from each ctDNA sample and only 17% (2% to 60.%) of mutations were clonal mutations suggesting substantial genomic heterogeneity. Single gene mutations were not associated with survival. However, mean variant allele frequency of clonal mutations (clonal-VAF) at baseline was associated with progression-free survival (PFS) and overall survival (OS) independent of stage, age, or platinum sensitivity. The median PFS of patients with higher versus lower than median clonal-VAF was 5.2 months (95% CI, 4.6 to 5.8 months) versus 10.0 months (95% CI, 9.3 to 10.7 months), p=0.002. The median OS was 8.1 months (95% CI, 5.5 to 10.7 months) versus 24.9 months (95% CI, 0.0 to 51.2 months) in patients with higher versus lower than median clonal-VAF, respectively, p=0.004. Analysis of serial ctDNA before and during treatment showed that clonal-VAF closely tracked closely with treatment responses.
Conclusion:
ctDNA sequencing is a promising modality for genomic profiling and disease monitoring for SCLC patients. Clonal VAF may be a better ctDNA metric than single gene mutations.
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P2.03 - Chemotherapy/Targeted Therapy (ID 704)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Chemotherapy/Targeted Therapy
- Presentations: 1
- Moderators:
- Coordinates: 10/17/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P2.03-028 - Third Generation EGFR Inhibitor AST2818 (Alflutinib) in NSCLC Patients with EGFR T790M Mutation: A phase1/2 Multi-Center Clinical Trial (ID 8968)
09:30 - 09:30 | Author(s): S. Zhang
- Abstract
Background:
AST2818 (Alflutinib) was designed to inhibit EGFR active mutations as well as the T790M acquired resistant mutation. The purpose of this study was to determine the safety and antitumor activity of AST2818 in EGFR T790M positive non-small cell lung cancer (NSCLC) patients after the first-generation EGFR-TKIs treatment failure.
Method:
Patients with histologically diagnosed, EGFR T790M mutant stage IV NSCLC were considered eligible, and they should have documented disease progression on EGFR-TKIs. In a 3+3 dose-escalation design, AST2818 was orally administered every day on a 21-day cycle at doses ranging from 20mg to 240 mg (NCT02973763). AST2818 was then explored in a dose-expansion cohort at doses ranging from 40 to 240 mg every day. Plasma samples were collected to evaluate pharmacokinetics of AST2818. EGFR T790M mutation in tissue samples was detected by amplification refractory mutation system. The primary endpoint was to determine dose limiting toxicity and objective response rate (ORR). Adverse events (AEs) were evaluated by CTCAE 4.03, and efficacy was assessed per RECIST v1.1 every 6 weeks.
Result:
From December 27, 2016 to August 21, 2017, 17 patients received at least one dose of AST2818 across four cohorts (20mg, 40mg, 80mg and 160 mg QD). Maximum tolerated dose has not been reached. The most common treatment-related AEs were grade 1 proteinuria (25%, 3/12). Other AEs included fatigue and prolonged Q-T interval, etc, all less than 10% and grade 1 or 2. The first 12 patients had been evaluated with an ORR of 58.3% (7/12) and a disease control rate of 91.7% (11/12). Profound and sustained tumor regression had already been observed at 20mg cohort. AST2818 plasma exposure, measured as Cmax and AUC 0-24h showed a dose-proportional increase. Figure 1
Conclusion:
AST2818 was well tolerated and had promising clinical activity with durable disease control in EGFR T790M mutant NSCLC after first-generation EGFR-TKIs treatment failure.
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P3.01 - Advanced NSCLC (ID 621)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.01-021 - A Multicenter, Non-Interventional Study on Real World EGFR Testing and in Patients with IIIB/IV NSCLC in Northern China (ID 8897)
09:30 - 09:30 | Author(s): S. Zhang
- Abstract
Background:
EGFR mutation plays a dominant role in the precise treatment of non-small cell lung cancer (NSCLC), and EGFR-TKIs has been recommended for patients with positive EGFR-sensitive mutation as a standard regimen in clinical practice. In China, application of EGFR-TKIs without knowing EGFR mutation status has been a common phenomenon due to various reasons including the vast territory, uneven distribution of medical resources, differences level of testing technology and others. Therefore, we prospectively conducted a real-world investigation to understand the actual situation of EGFR testing in Northern China, and identify the underlying causes affecting EGFR detection, in order to provide references to improve the standardized treatment.( NCT02620657)
Method:
The patients with IIIB/IV NSCLC who were firstly diagnosed or postoperative recurrence between 2014-1-1 and 2014-12-31 in 28 research centers of Northern China were analyzed. The primary endpoint was testing rate，the secondary endpoints were factors affecting EGFR testing, EGFR mutation status, detection methods and the survival outcomes of patients.
Result:
Among 2809 patients, 2250(90.78%) were adenocarcinoma, 208(7.40%) were squamous carcinoma, 51(1.82%) were other pathologic types. Testing rate was 42.54%(1195/2809) and was significantly related to city level (first-tier cities vs. new first-tier cities vs. second-tier cities vs. third-tier and above cities : 69.04% vs. 38.08% vs. 34.05% vs. 14.11%, P < 0.001), smoking status (never smoking vs. ever smoking vs. smoking: 45.42% vs. 51.10% vs. 33.37%, P<0.001), ECOG PS(0 vs.1vs.2vs.≥3:47.93%vs. 44.48vs.34.89%vs.20.37%, P=0.011), pathological type (adenocarcinoma vs. squamous carcinoma: 44.94% vs.19.23%, P=0.003) and medical insurance situation (social basic medical insurance vs. new rural cooperative medical insurance vs. own expense: 44.98% vs. 36.49% vs. 29.55%, P=0.001). EGFR sensitive mutation rate was 46.44%, the most common subtype was 19Del(42.16%), followed by L858R(40.00%), Exon 20 insertions(1.62%) and other subtypes(16.20%). The most common methodology is ARMS(63.77%), the second common one is DNA sequencing(5.36%). The 1-year and 2-year survival rate in patients receiving EGFR testing was 73.6%and 51.9%, compared with 64.3% and 43.7% respectively in patients without EGFR testing.
Conclusion:
There were regional differences in EGFR testing rates among IIIB/IV NSCLC patients in Northern China. The intention of doctors and patients, medical insurance coverage and differences technical level are major factors affecting the testing rate of EGFR. Approaches should be taken to improve the situation, such as strengthening the training, expanding the coverage of medical insurance, and relying on commercial gene detection companies, and further standardize the molecularly pathological diagnosis and treatment of NSCLC.
