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Collin Blakely
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MA11 - Biomarkers of IO Response (ID 912)
- Event: WCLC 2018
- Type: Mini Oral Abstract Session
- Track: Immunooncology
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 10:30 - 12:00, Room 203 BD
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MA11.09 - Single-Cell Characterization of the Immunologic Microenvironment in Advanced-Stage, Oncogene-Driven NSCLC (ID 12122)
11:30 - 11:35 | Author(s): Collin Blakely
- Abstract
- Presentation
Background
The immunologic microenvironment in oncogene-driven non-small cell lung cancer (NSCLC) is poorly understood. Despite high initial response rates to tyrosine kinase inhibitors (TKIs) in patients with oncogene-driven NSCLC, responses are incomplete and transient. Furthermore, response rates to subsequent checkpoint inhibitor immunotherapies are very low. Understanding the immunologic microenvironment may facilitate understanding treatment resistance in this population.
a9ded1e5ce5d75814730bb4caaf49419 Method
From October 2016 to March 2018 we performed single-cell sequencing on 35 tissue samples from 28 patients with NSCLC. Fresh tissue samples were obtained at time of standard of care biopsies and as research sample collections. Single-cell level whole transcriptome RNA sequencing was performed using SmartSeq2. Cells were clustered into distinct cell states on a multi-dimensional gene expression space and visualized using t-distributed stochastic neighbor embedding (t-SNE) for further dimensionality reduction. Cellular identities for each cluster were established by examining the enrichment of known cell-type specific genes across all distinct clusters.
4c3880bb027f159e801041b1021e88e8 Result
Tumor samples were obtained from predominantly stage IV lung adenocarcinoma (90.6%) harboring an oncogenic driver (EGFR-mutant 50%, ALK-rearranged 21.9%, BRAF V600E 9.4%, ROS1-rearranged 9.4%, MET exon 14 skipping 6.3%, and KRAS-mutant 3.1%). Samples were collected prior to treatment (21.9%), during treatment (46.9%), and at disease progression on therapy (31.3%). All patients with a targetable oncogenic driver received a standard of care TKI and the KRAS-mutant patient received pembrolizumab monotherapy. A total of 6048 cells were isolated, including 3457 immune cells, with an average of one million reads and 2500 genes per cell. The immunologic microenvironment (average 108 immune cells/sample) included macrophages/monocytes (33% of cells), T cells (31.9%), and B cells (11.6%), as well as a smaller fraction (<10%) of dendritic cells, Langerhans cells, mast cells, neutrophils, and NK cells. Unbiased gene expression-based subclustering of T cells identified 7 distinct T cell populations, including naïve (22.6%), cytotoxic and/or memory T cells (44.1%), and T regulatory cells (5.6%), as well as 6 tumor-associated macrophage populations with distinct gene expression patterns.
8eea62084ca7e541d918e823422bd82e Conclusion
Single-cell RNA sequencing to identify immune cell populations is feasible in advanced-stage NSCLC biopsy specimens across multiple time points during treatment. Here, we describe the heterogeneity of infiltrating immune cell phenotypes including T cell and macrophage subtypes. An improved understanding of the immunologic microenvironment in oncogene-driven NSCLC may facilitate patient selection for immunotherapy treatment and aid in the rational design of alternative or combination immunotherapy strategies for a patient population rarely responsive to current immunotherapeutic agents.
6f8b794f3246b0c1e1780bb4d4d5dc53Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
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P1.13 - Targeted Therapy (Not CME Accredited Session) (ID 945)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/24/2018, 16:45 - 18:00, Exhibit Hall
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P1.13-10 - Aurora Kinase A Drives the Evolution of Resistance to Third Generation EGFR Inhibitors in Lung Cancer (ID 13433)
16:45 - 18:00 | Author(s): Collin Blakely
- Abstract
Background
Paradigm defining for precision medicine, EGFR inhibitors are a major breakthrough in the treatment of EGFR-mutant non-small cell lung cancer (NSCLC). Although these EGFR-TKI therapies often elicit profound initial therapeutic responses, their effects are transient due to residual disease. This residual disease and subsequent disease progression occurs through tumor evolution and molecular drivers behind the formation, maintenance and evolution of residual disease and acquired resistance have remained elusive. Although in many cases pre-existing clones with bona-fide genetic resistance have been identified, majority of patients have undetectable resistance causing genetic alterations suggesting that non-genetic alterations may drive altered cell state and signaling associated with EGFR inhibitor resistance. Furthermore, in the case of osimertinib now used in first line setting, mechanisms of acquired resistance have been ill defined and no effective second line therapies exist.
a9ded1e5ce5d75814730bb4caaf49419 Method
Using EGFR mutant lung cancer cells we developed eight distinct in vitro models of acquired resistance to 3rd generation EGFR-TKI inhibitors, osimertinib and rociletinib. We examined the efficacy of drug combinations in vivo using both cell line xenografts and PDX models of EGFR TKI resistance. We measured the level of staining of the candidate biomarker, TPX2, in patients progressing on first and third-generation EGFR TKIs.
4c3880bb027f159e801041b1021e88e8 Result
Chemical screens in acquired resistant cell lines revealed that Aurora kinase inhibitors are highly synergistic when combined with third-generation EGFR inhibitors. Resistant cells harbored heightened activation of AURKA caused by upregulation of its co-activator protein TPX2. In in-vitro and in-vivo models of acquired resistance the combination induced potent cell death by reactivating BIM-mediated apoptosis. We found that tumors from the majority of patients progressing on first and third-generation EGFR TKIs harbored high levels of TPX2, indicating that AURKA is likely activated and driving resistance in a significant fraction of EGFR-mutant lung cancers.
Tracking the kinetics of AURKA activation, we found that AURKA activity is required for the formation and maintenance of residual drug tolerant cells, precursors of acquired resistance. Either single agent EGFR-TKI, the AURKA inhibitor MLN8237 or the combination enhanced the magnitude of response and forestalled the emergence of resistance in vitro as compared to monotherapies. The combination robustly induced tumor regressions in an EGFR L858R PDX tumor model generated from a residual disease surgical specimen.
8eea62084ca7e541d918e823422bd82e Conclusion
This synthetic lethal interaction between EGFR TKIs and Aurora kinase inhibitors has important clinical implications for the development of better treatment strategies using EGFR-TKIs and suggest a new paradigm for preventing the emergence of resistance.
6f8b794f3246b0c1e1780bb4d4d5dc53
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P2.16 - Treatment of Early Stage/Localized Disease (Not CME Accredited Session) (ID 965)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
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P2.16-12 - Expanded Data Confirm Molecular Testing Identifies Lung Adenocarcinoma Patients, Including Stage IA, Who Benefit from Adjuvant Chemotherapy (ID 14532)
16:45 - 18:00 | Author(s): Collin Blakely
- Abstract
Background
A clinically certified, 14-gene quantitative PCR expression assay has been validated to assess mortality risk in early-stage lung adenocarcinoma. Molecular stratification may identify those stage I-IIA patients who are in most need of potentially life-saving intervention after resection, including stage IA patients for whom chemotherapy is never recommended.
a9ded1e5ce5d75814730bb4caaf49419 Method
Prospective molecular risk-stratification by the 14-gene assay was performed on 200 consecutive patients with stage I-IIA lung adenocarcinoma after complete surgical resection at a single institution. Adjuvant chemotherapy was recommended for molecular high-risk patients. Kaplan-Meier analysis and log-rank tests were used to evaluate differences in disease free survival.
4c3880bb027f159e801041b1021e88e8 Result
Average age of patients was 68 +/- 10 years, 62% were female and mean follow up was 24 months. The recurrence rate among all patients was 9%. However, 87 patients (44%) were found to be molecular high-risk and had a recurrence rate of 17%, whereas the 113 patients (56%) who were molecular low-risk had a recurrence rate of only 3% (p<0.0001). Even among the stage IA patients, 41 (33%) were found to be molecular high-risk. The recurrence rate in molecular low-risk stage IA patients was only 1%, compared to 15% in stage IA patients who were identified as molecular high-risk (log-rank p=0.003). Of the 41 stage IA patients found to be molecular high-risk, 24% agreed to undergo adjuvant chemotherapy; there have been no recurrences among these treated high-risk patients. In contrast, the KM estimate of 5-year disease free survival among stage IA high-risk patients who did not receive adjuvant chemotherapy was 51% (log-rank p=0.005).
8eea62084ca7e541d918e823422bd82e Conclusion
This prospective, single-institution study further demonstrates the clinical utility of the 14-gene molecular prognostic assay in the management of early stage lung adenocarcinoma. Adjuvant chemotherapy guided by molecular prognosis in the earliest stages of disease, including stage IA, may prevent a significant number of recurrences and deaths.
6f8b794f3246b0c1e1780bb4d4d5dc53
