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G.M. Frampton
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OA10 - EGFR Mutations (ID 382)
- Event: WCLC 2016
- Type: Oral Session
- Track: Biology/Pathology
- Presentations: 1
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OA10.01 - Comprehensive Genomic Profiling and PDX Modeling of EGFR Exon 20 Insertions: Evidence for Osimertinib Based Dual EGFR Blockade (ID 4375)
11:00 - 12:30 | Author(s): G.M. Frampton
- Abstract
Background:
EGFR exon 20 insertion mutations (EGFRex20ins) comprise a subset of EGFR activating alterations relatively insensitive to 1[st] and 2[nd] generation EGFR-TKIs. Comprehensive genomic profiling (CGP) integrated with PDX modeling may identify new EGFR-inhibition strategies for EGFRex20ins.
Methods:
EGFRex20ins and co-occurring genomic alterations were identified by hybrid-capture based CGP performed on 14,483 consecutive FFPE lung cancer specimens to a mean coverage depth of >650X for 236 or 315 cancer-related genes plus 47 introns from 19 genes frequently rearranged in cancer. An EGFRex20ins(N771_P772>SVDNP)/EGFR-amplified tumor (24 copies) from this cohort was implanted subcutaneously into the flank of NOD.Cg-Prkdc[scid]Il2rg[tm1Wjl]/SzJ (NSG) mice for tumor growth inhibition studies (TGI) with vehicle, erlotinib (50 mg/kg PO daily), osimertinib (25 mg/kg PO daily), and osimertinib (25 mg/kg PO daily) plus cetuximab (10 mg/kg IV, 2x/week) administered for 21 days.
Results:
CGP identified 263/14,483 cases (1.8%) with EGFRex20ins, which represent 12% (263/2,251) of EGFR activating mutations in this series. 90% (237/263) were NSCLC-adenocarcinoma, 9% (23/263) were NSCLC-NOS, and 1% (2/263) were sarcomatoid carcinoma. Over 60 unique EGFRex20ins were identified, most commonly D770_N771>ASVDN (21%) and N771_P772>SVDNP (20%); 6% (15/263) harbored EGFR A763_Y764insFQEA, an EGFRex20ins typically sensitive to erlotinib. Among EGFRex20ins cases, EGFR-amplification occurred in 22% (57/263). Putative co-occurring driver alterations including EGFR (ex19del and L858R), Her2, MET and KRAS tended to be mutually exclusive, occurring only in 5% (12/263) of cases. The most common co-occurring alterations affected TP53 (56%), CDKN2A (22%), CDKN2B (16%), NKX2-1 (14%) and RB1 (11%). Average tumor mutation burden was low (mean 4.3 mutations/Mb, range 0-40.3 mutations/Mb). Clinical outcomes to 1st and 2nd generation EGFR-TKIs were obtained for a subset of cases with various EGFRex20ins, and 0/6 patients had responses. However, robust TGI was observed with combination osimertinib and cetuximab in a highly EGFR-amplified PDX model with a conserved EGFRex20ins (N771_P772>SVDNP) not associated with response to earlier generation EGFR-TKI, and was superior to vehicle, erlotinib or osimertinib alone (D21 mean tumor size 70 mm[3] vs. 1000, 800, 225 mm[3] respectively; p-values all <0.001).
Conclusion:
Diverse EGFRex20ins were detected in 12% of EGFR-mut NSCLC. Available clinical outcomes data demonstrated lack of response to 1[st] and 2[nd] generation EGFR-TKIs. Identification of co-occurring EGFR-amplification in 22% of cases led to testing of a dual EGFR blockade strategy with an EGFR monoclonal antibody and osimertinib, which demonstrated exceptional tumor growth inhibition in an EGFRex20ins PDX minimally responsive to erlotinib. These findings can rapidly be translated into an ongoing clinical trial of osimertinib and necitumumab.
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OA20 - Immunotherapy and Markers (ID 401)
- Event: WCLC 2016
- Type: Oral Session
- Track: Biology/Pathology
- Presentations: 1
- Moderators:M. Früh, C.S. Baldotto
- Coordinates: 12/07/2016, 11:00 - 12:30, Stolz 2
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OA20.01 - Tumor Mutation Burden (TMB) is Associated with Improved Efficacy of Atezolizumab in 1L and 2L+ NSCLC Patients (ID 6149)
11:00 - 12:30 | Author(s): G.M. Frampton
- Abstract
- Presentation
Background:
In NSCLC, atezolizumab (anti-PDL1) efficacy correlates with PD-L1 expression on tumor cells (TC) and tumor-infiltrating immune cells (IC). Here we examined the association between atezolizumab efficacy and TMB assessed by FoundationOne (F1) sequencing panel.
Methods:
Pretreatment tumor specimens from 102 1L and 465 2L+ NSCLC patients enrolled on three Ph 2 atezolizumab monotherapy trials (POPLAR: randomized 2/3L trial comparing atezolizumab vs docetaxel; BIRCH/FIR: single-arm, 1L/2L+ PD-L1‒selected trials) were available for targeted genetic sequencing using the F1 panel of 315 cancer-related genes. TMB was quantified using an updated TMB algorithm and efficacy was assessed in groups defined by the 75th (high) and 50th (median) percentile of each study-specific TMB. Atezolizumab efficacy was examined at Dec 1, 2015 (POPLAR and BIRCH); and Jan 7, 2015 (FIR) data cutoffs.
Results:
Across samples, median TMB was similar in 1L and 2L+ patients (9/MB and 9.9/MB, respectively). In 1L and 2L+ PD-L1–selected patients, atezolizumab benefit was increased in those with ≥ TMB cut-offs (Table). In unselected 2L+ patients from POPLAR, the OS, PFS, and ORR benefits of atezolizumab vs docetaxel were also enhanced in patients with increased TMB. TMB and PD-L1 expression were independently associated with improved atezolizumab efficacy. TMB associations with PD-L1 expression, tumor-infiltrating lymphocyte infiltration and T-effector cell gene expression will be presented.
Conclusion:
For the first time, we demonstrate that TMB assessed with F1 targeted sequencing is associated with improved atezolizumab outcomes in 1L and 2L+ NSCLC. Moreover, this is the first study demonstrating the association of TMB with improved anti-PD-L1/PD-1 efficacy in a randomized trial. Importantly, the association between TMB and atezolizumab efficacy occurred in both unselected and PD-L1-selected patients. Therefore, in addition to PD-L1, TMB may be an independent predictor of improved responsiveness to atezolizumab in advanced NSCLC.Atezolizumab efficacy by TMB subgroups PD-L1‒selected BIRCH+FIR 1L n=102 2L+n=371 Median (≥9/MB) High (≥13.5/MB) Median (≥9.9/MB) High (≥17.1/MB) OS,HR[a] (95% CI) 0.79 (0.39-1.58) 0.45 (0.17-1.16) 0.87 (0.65-1.16) 0.7 (0.49-1.00) PFS,HR[a] (95% CI) 0.58 (0.36-0.94) 0.54 (0.3-0.97) 0.64 (0.5-0.8) 0.5 (0.38-0.67) ORR,above/below cutoff 28%/13% 25%/20% 25%/14% 29%/16% POPLAR 2L+ unselected n=92 Biomarker- evaluable population Median (≥9.9/MB) High (≥15.8/MB) OS,HR[b ] (95% CI) 0.65 (0.38-1.12) 0.48 (0.23-1.04) 0.5 (0.15-1.67) PFS,HR[b] (95% CI) 0.98 (0.63-1.53) 0.49 (0.25-0.93) 0.49 (0.19-1.3) ORR,atezolizumab/docetaxel 13%/15% 20%/4% 20%/8% [a]HR:efficacy-evaluable patients, atezolizumab at/above cutoff vs below.[b]HR:efficacy-evaluable patients, atezolizumab vs docetaxel at/above cutoff.
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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-068 - The Druggable Mutation Landscape of Lung Adenocarcinoma (ID 5470)
14:30 - 15:45 | Author(s): G.M. Frampton
- Abstract
Background:
Molecularly targeted therapies and immunotherapies have emerged as promising approaches in the fight against advanced-stage cancers, including lung adenocarcinoma. Identifying genomic alterations predictive of targeted therapy response, as well as biomarkers for immunotherapy response, such as tumor mutation burden (TMB), could minimize the utilization of ineffective therapies and help overcome tumor drug resistance, improving patient outcomes. We examined the largest previously described dataset, consisting of genomic alterations of ~10,000 lung adenocarcinoma patients, to characterize the landscape of druggable alterations and identified previously undetected co-occurrence and exclusivity relationships between genomic alterations.
Methods:
Comprehensive genomic profiling (CGP) based on hybrid capture-based next-generation sequencing of the full coding regions of up to 315 cancer-related genes was performed on 10,472 lung adenocarcinomas. Base substitutions, indels, copy number alterations and gene fusion/rearrangements were assessed. TMB was calculated as the number of somatic, coding, base substitutions and indels per megabase of genome examined (high TMB: ≥20 mutations/Mb).
Results:
Patient median age was 65 years (range: 13 to >90 years), and 56% were female. The alteration frequencies of the druggable NCCN lung adenocarcinoma guideline genes were: EGFR (20.5%), BRAF (5.8%), ERBB2 (5.7%), c-MET (5.2%), ALK (4.3%), RET (2.1%), and ROS1 (1.4%). 57.5% and 2.5% of samples had alterations in zero or multiple of these genes, respectively. Few cases with high TMB were found in samples with alterations in EGFR (3.6%) or ALK (2.6%), while a larger percentage with alterations in BRAF (12.9%) or zero NCCN genes (17.4%) had high TMB. 269 cancer-related genes were each altered in ≥0.1% of cases without alterations in NCCN genes or high TMB, including genes that are becoming clinically relevant, such as STK11 (24.8%), MYC (8.4%), NF1 (8.2%), PIK3CA (5.2%), RICTOR (3.7%), CDK4 (2.8%), CCND1 (2.8%), BRCA2 (1.7%), and NRAS (1.3%). Detailed co-occurrence and exclusivity relationships for all genomic alterations will be presented. EGFR, RET, and ROS1 alterations were most common in female cases, and ALK- and ROS1-altered tumors had the lowest patient age distributions (medians: 57 and 55 years, respectively).
Conclusion:
Using CGP, >50% of patients with lung adenocarcinoma had an alteration in at least one NCCN gene (42.5%), a high TMB status (12.3%), or both (2.3%). Amongst those with neither, 47.5% had an alteration in a gene with emerging evidence for clinical utility. Given the robustness of the dataset, this analysis suggests a significant expansion of the patient population eligible for personalized anti-lung cancer treatment through combination therapy and immunotherapy.
