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A. Futreal
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MA14 - Immunotherapy in Advanced NSCLC: Biomarkers and Costs (ID 394)
- Event: WCLC 2016
- Type: Mini Oral Session
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:M. Reck, D.R. Spigel
- Coordinates: 12/06/2016, 16:00 - 17:30, Strauss 2
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MA14.03 - The Impact of Genomic Landscape of EGFR Mutant NSCLC on Response to Targeted and Immune Therapy (ID 6242)
16:12 - 16:18 | Author(s): A. Futreal
- Abstract
- Presentation
Background:
EGFR mutations define a distinct subset of NSCLC characterized by clinical benefit from tyrosine kinase inhibitors. The impact of genomic alterations that coexist with EGFR mutations is not fully understood. In addition, the responsiveness of EGFR mutant NSCLC to immune checkpoint blockade is not well defined.
Methods:
We queried our prospectively collected MD Anderson Lung Cancer Moon Shot GEMINI Database to identify EGFR mutant NSCLC patients. We analyzed the genomic landscape of these tumors derived from next generation sequencing, performed as part of routine clinical care, to comprehensively describe the concurrent genomic aberrations in EGFR mutant NSCLC and their impact on clinical outcomes. We used log rank and Fisher’s exact tests to identify associations between co-concurrent mutations and clinical outcomes.
Results:
1958 non-squamous NSCLC patients were identified in the GEMINI database. The frequency of EGFR mutations was 14.1% (n=276). Among EGFR mutant patients, 188 underwent targeted next generation sequencing of a minimum of 46 cancer related genes. The majority of EGFR mutant patients (77.6%, n=146) had at least one coexisting mutation. The most frequent co-mutations identified were TP53 (47%, n=88), CTNNB1 (7.5%, n= 14) and PIK3CA (6.5%, n=12). ALK and ROS1 translocations were found to coexist with EGFR mutations in one patient each. Of patients treated with a first or second generation TKI, concurrent TP53 mutations were associated with a shorter progression free survival (HR= 1.81, P= 0.039). Eight patients with EGFR/CTNNB1 co-mutations developed acquired TKI resistance with T790M secondary mutation being the resistance mechanism in six (75%) of them suggesting that coexisting mutation can dictate emerging resistance mechanisms. Twenty patients were treated with anti PD1/PD-L1 agents (nivolumab n= 18, pembrolizumab n=2). Only two (10%) patients achieved confirmed radiological response, one lasting for 6 months and the second ongoing at 6 months. Both patients were never smokers, one with EGFR exon 20 insertion and no concurrent mutations, and the other with EGFR exon 19 deletion and TP53 mutation. Sixteen patients developed confirmed progressive disease. Finally, one patient with 17 pack-year smoking history, EGFR G719/S768I double mutation and concurrent PIK3CA mutation achieved stable disease lasting for four months. The median progression free survival for the cohort treated with immunotherapy was 2 months (range: 1-not reached).
Conclusion:
Concurrent genomic aberrations may predict response duration to TKIs and may be associated with particular emerging resistance mechanisms to TKIs in EGFR mutant NSCLC. Immunotherapy results in durable clinical benefit in a subset of EGFR mutant NSCLC patients.
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P1.07 - Poster Session with Presenters Present (ID 459)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: SCLC/Neuroendocrine Tumors
- Presentations: 1
- Moderators:
- Coordinates: 12/05/2016, 14:30 - 15:45, Hall B (Poster Area)
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P1.07-024 - EGFR Mutations in Small Cell Lung Cancer (SCLC): Genetic Heterogeneity and Prognostic Impact (ID 4154)
14:30 - 14:30 | Author(s): A. Futreal
- Abstract
Background:
EGFR mutations in SCLC were first reported in cases of lung adenocarcinoma which transformed to SCLC after TKI treatment and such mutation was speculated to be a TKI resistance mechanism. Recently case reports and high throughput sequencing in a small number of samples suggested that EGFR mutations do exist in de novo SCLC. But the genetic and clinical characteristics have not been studied in large number of samples. This study aims to conduct a large scale survey of the EGFR mutations among Chinese SCLC patients, and to analyze the genetic and clinical characteristics of such mutations.
Methods:
Mutation status in exon 18-21 of EGFR was assessed by dideoxy-sequencing in 565 SCLC tumors treated in Zhejiang Cancer Hospital, Hangzhou, China from 2009 to 2014 and correlated with clinical parameters. Chi-square test were used to show the correlation of clinic variables with EGFR mutation. Survival analysis was performed using the Kaplan-Meier method.
Results:
40 instances of EGFR mutation are detected in 565 clinical samples. The mutation rate is 7.1%. Besides classic mutations E19 deletion（n=3）and E21 L858R(n=3), the rest of the mutations detected are atypical including E18 (G719D/S, G696R, S695N/D, N700D, I715F, L688F, P694L), E19(K757N, A755V, V742I, E736K, N756Y, E749K, P753L, A755T), E20 (T790M, H773R, S768R/N, R776H/C, G796D, D807N, R803W/Q, Y813C, G810S, A763T, G779D, Q791R, C781Y, N771S), E21(L858V, G874R, K867E). Among the EGFR mutation positive patients, 27.5% (11/40) are non-smokers, higher than the EGFR negative group (16.4%, 86/525). But it is not statistically significant (p=0.129). And EGFR mutation is not correlated with sex (female vs male), age (≥65y vs <65y) or clinical stages (limited stage vs extensive stage). After matching the treatment history of the EGFR mutation positive and negative patients (excluding patients who were not treated ,only treated by traditional Chinese medicine or one cycle chemotherapy or biological therapy , treatment unkown ), univariate analysis shows that the EGFR mutation positive patients have better overall survival than the EGFR negative group, with medium OS of 24.433m±4.864m vs 14.00m±0.838m respectively (p=0.018). COX regression analysis suggests that limited stage (HR=2.610), <65 years (HR=1.476) and EGFR mutation (HR=0.587, p=0. 0.039) were independently predictive of better OS.
Conclusion:
Among the de novo SCLC patients diagnosed, there exists a group harboring EGFR mutations, most of which are non-classic mutations. After matching the treatment history of patients, analysis reveals that EGFR mutations are predictive of better OS.
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P2.03b - Poster Session with Presenters Present (ID 465)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 12/06/2016, 14:30 - 15:45, Hall B (Poster Area)
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P2.03b-023 - Circulating Tumor DNA (ctDNA)-Based Genomic Profiling of Known Cancer Genes in Lung Squamous Cell Carcinoma (LUSC) (ID 5393)
14:30 - 14:30 | Author(s): A. Futreal
- Abstract
Background:
Next-generation sequencing (NGS) of ctDNA is increasingly used for non-invasive genomic profiling of human cancers. However, studies to date have not detailed the ctDNA genomic landscape in LUSC.
Methods:
From June 2014 to June 2016, ctDNA from 467 patients with stage 3 or 4 (AJCC 7[th] edition) LUSC (60% male, 40% female; median age of 69 [range 27-96]) were tested with Guardant 360[TM], a ctDNA NGS assay that detects single nucleotide variants (SNVs) of 54-70 cancer genes and certain copy number amplifications (CNAs), indels, and fusions. The median time between diagnosis and ctDNA testing was 238 days. Somatic alterations were compared with those in the 2016 LUSC TCGA dataset.
Results:
426 patients (92.2%) had at least one somatic alteration detected. The most commonly observed SNVs (> 5% frequency) were TP53 (64.8%), PIK3CA (7.8%), CDKN2A (6.1%), and KRAS (5.9%). Frequencies of SNVs known to be significant in LUSC correlated well between our cohort and the TCGA (Spearman r = 0.93) but were generally lower in our cohort (Table 1). Several of our most frequently observed CNAs are strongly associated with LUSC (EGFR, CDK6, MYC, ERBB2, PDGFRA, KIT, CCND1). In addition, MET exon 14 skipping (1.3%), EGFR exon 19 deletion (1.9%), EGFR exon 20 insertion (0.5%), ERBB2 exon 20 insertion (0.3%) and EML4-ALK fusion (0.7%) were detected. These alterations have rarely been reported in LUSC.
Conclusion:
Patterns of SNVs and CNAs in LUSC obtained by ctDNA profiling are largely consistent with those from TCGA tissue profiling, although the frequency of key SNVs is lower. The presence of actionable alterations atypical for LUSC in 4.7% of this clinical cohort may represent underappreciated treatment options. Further investigation is warranted to evaluate whether these findings reflect a distinct mutational landscape in heavily treated advanced disease (which is under-represented in the TCGA) and/or challenges in histopathological classification. Figure 1
