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Jordan Dozier
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MA06 - PDL1, TMB and DNA Repair (ID 903)
- Event: WCLC 2018
- Type: Mini Oral Abstract Session
- Track: Biology
- Presentations: 1
- Moderators:
- Coordinates: 9/24/2018, 13:30 - 15:00, Room 206 AC
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MA06.06 - An Ex-Vivo Patient-Derived, Immunocompetent (PDI) Culture System to Evaluate Immunotherapeutic Agents’ Anti-Tumor Efficacy (ID 14299)
14:05 - 14:10 | Author(s): Jordan Dozier
- Abstract
- Presentation
Background
Anti-tumor efficacy of human immunotherapeutic agents, such as antibodies, chimeric antigen receptor (CAR) and T-cell receptor transduced T cells, are currently being investigated in immunodeficient mice prior to clinical translation. We developed and optimized an ex-vivo culture system utilizing malignant pleural effusions (MPEs) to compliment these investigations in a human, immunocompetent, tumor-like environment. We hypothesized that CAR T cells’ cytotoxicity will vary by the different immune compositions in each MPE, which are conditions unavailable in current efficacy assays.
a9ded1e5ce5d75814730bb4caaf49419 Method
Mesothelin-targeted CAR T cells from multiple donors were exposed to MPEs derived from non-small cell lung cancer patients (n=15) and RPMI culture medium. Influence of the MPEs on CAR T-cell efficacy was evaluated by viability and phenotype (flow cytometry), cytotoxicity (chromium release assay), and gene expression (NanoString). Group-based trajectory modeling was used to stratify the inhibitory effect of MPEs. MPE composition (ELISA and Luminex assays) was evaluated to interpret its influence on CAR T cells.
4c3880bb027f159e801041b1021e88e8 Result
With the incorporation of our optimized protocols, T cells retain their viability, phenotype (CD4/CD8), and percentage of CAR expression when cultured in MPEs. MPE soluble factor levels remained stable over multiple freeze/thaw cycles. CAR T cells co-cultured in MPE exhibited variable antigen-specific cytotoxicity (Fig. A). MPE-induced T-cell inhibition was stratified into groups of strong, mild, or no inhibition. (Fig. B). Compared to MPEs with either mild or no inhibition, MPEs with strong inhibition had significantly higher levels of TGFβ-2 (average TGFβ-2 level in strong vs. mild inhibition: 402 vs. 50 pg/mL, p<0.05) (Fig. C), IL-6, RANTES, and IL-5.
8eea62084ca7e541d918e823422bd82e Conclusion
We present the first human immunocompetent culture system that can be used to evaluate immunotherapeutic agents’ efficacy prior to their clinical translation. Furthermore, analyses of the culture system’s soluble factors sheds light on their relative influence on T-cell efficacy.
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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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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MA11.01 - Comparative Efficacy of T-Cell Intrinsic Versus Extrinsic PD-1 Blockade to Overcome PD-L1+ Tumor-Mediated Exhaustion (ID 14194)
10:30 - 10:35 | Presenting Author(s): Jordan Dozier
- Abstract
- Presentation
Background
Anti-PD-1 agents are effective in overcoming PD-L1+ mediated T-cell exhaustion. Effective therapeutic regimens include multiple, long-term administration. We hypothesized that a single dose of T-cell intrinsic PD-1 blockade by expression of a dominant negative receptor (PD1-DNR) can be equally effective as multiple doses of anti-PD-1 agent administration in the treatment of PD-L1 overexpressing thoracic cancers.
a9ded1e5ce5d75814730bb4caaf49419 Method
Human T cells engineered to target the cancer-antigen mesothelin (MSLN) by expression of a chimeric antigen receptor (CAR) with or without co-transduction with a PD1-DNR underwent repeated antigen stress with cancer cells with constitutive overexpression of PD-L1. For comparative efficacy evaluation, anti-PD-1 antibody was co-administered with CAR T cells (CARs). In vitro efficacy was evaluated by cytotoxicity (chromium-51 release assay). In vivo, mice with established pleural tumor were treated with either a single dose of MSLN CARs (with and without anti-PD-1 agent) or MSLN PD1-DNR CARs. Tumor burden regression by bioluminescence imaging and median survival were evaluated.
4c3880bb027f159e801041b1021e88e8 Result
In vitro, constitutive PD-L1 overexpression (Fig. A) inhibits MSLN CAR effector function as evidenced by a decrease in cytotoxicity following repeated stimulation with MSLN+PD-L1hi tumor cells (Fig B). MSLN PD1-DNR CARs had increased cytotoxicity when compared to MSLN CARs with or without high frequency anti-PD-1 antibody supplementation. In vivo, mice treated with MSLN CAR (with or without anti-PD-1 antibody) or MSLN PD1-DNR CARs demonstrated enhanced tumor regression (Fig C) and prolonged median survival (Fig D) compared to MSLN CARs alone. Furthermore, a single low dose of MSLN PD1-DNR CARs shows equal anti-tumor efficacy compared to MSLN CARs with multiple doses of anti-PD-1 antibody.
8eea62084ca7e541d918e823422bd82e Conclusion
Our results demonstrate that CAR T cells engineered to express a cell-intrinsic PD-1 dominant negative receptor overcome PD-L1 mediated T-cell inhibition equally compared to multiple doses of anti-PD-1 antibody administration. A clinical trial with MSLN CAR PD1-DNR CAR T cells is being initiated.
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.
