Regular and Young Investigator Award Abstracts最新文献

{"title":"1304 Robust machine learning (ML) approach for screening microbiome ecosystem therapies (MET) drug candidates in combination with immune checkpoint inhibitors","authors":"Emmanuel Prestat, Elsa Schalck, Antoine Bonnefoy, Antoine Sabourin, Cyrielle Gasc, Carole Schwintner, Nathalie Corvaia","doi":"10.1136/jitc-2023-sitc2023.1304","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.1304","url":null,"abstract":"<h3>Background</h3> Studies for the last 8 years have connected gut microbiome composition to ICI efficacy in cancer therapy, including pilot studies^{1 2} demonstrating that FMT from responders to non-responders can improve response rates. However, interstudy inconsistencies were observed in microbiome signature findings³ also confirmed when reprocessing internally raw data from multiple studies. It remains critical to tackle this heterogeneity to learn from stable patterns and develop a robust and reliable drug candidate screening algorithm. Hence, MaaT Pharma developed an AI framework to train models from microbiota Whole Metagenome Sequencing (WMS) datasets that predict the responder status to ICIs. We focused on performance and robustness, which was achieved by monitoring the <i>AUC</i> as a standard approach, and <i>precision</i> to control for false positive rate and to emphasize the positive classification criticality in a drug candidate selection approach. <h3>Methods</h3> We collected baseline WMS datasets from 10 cohorts in 3 ICI indications: melanoma, non-small cell lung cancer and renal cell carcinoma, along with clinical evaluation of ICI treatment. Those datasets were processed by gutPrint® <i>MgRunner</i> software, before being included in the AI framework. About 70 experiments were conducted within a Leave-One-Dataset-Out cross-validation scheme. Various factors such as taxonomic or functional inputs, dataset bias correction, data augmentation approaches, ML algorithms and data representation methods, were tested to select the top ones. Finally, a model was refit with the best performing parameters on the entire dataset, and applied to score MaaT Pharma mono-donor and healthy-pooled-donors-derived drug substances (DS). <h3>Results</h3> The best performing experiment provided models based on the XGBoost algorithm with AUCs ranging from 0.52 to 0.73 depending on the left-out cohort (average AUC = 0.65), and a precision that ranges between 0.55 and 0.81 (average precision = 0.65). Those results outperform melanoma-centered study with a comparable method.⁴ Despite the diverse data sources and indications, the multi-indication approach surpassed the mono-indication (melanoma) training approach for predictions related to melanoma patients. Considering the scoring of DS derived from healthy donors, 73% of mono-donors and 91% of healthy-pooled-donors-derived DS were classified as ‘Responder-like’. <h3>Conclusions</h3> Present study highlights the significance of dataset size in ICI microbiota models and presents a methodology to enhance the performances of a multi-cohort-based ML approach. Conditioned to the performances we obtained, the healthy-pooled-donors-derived DS harbor a considerable ratio (91%) of ‘ICI Responder-like’, significantly higher than the mono-donor stools (73%) suggesting that pooled ecosystems from healthy donors could better convert ICI-non responders into responders. <h3>References</h3","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"644 A phase 1 dose escalation study of GCC19CART – A novel CoupledCAR® therapy for subjects with metastatic colorectal cancer","authors":"Naifei Chen, Chengfei Pu, Lingling Zhao, Ning Li, Chang Wang, Yusheng Huang, Suxia Luo, Xun Li, Zhenzhou Yang, Jun Bie, Ruihong Zhu, Xi Huang, Haiyang Tang, Tingting Liang, Yizhuo Wang, Beibei Jia, Dongqi Chen, Victor Lu, Zhao Wu, Yongping Song, Lei Xiao, Jiuwei Cui","doi":"10.1136/jitc-2023-sitc2023.0644","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0644","url":null,"abstract":"<h3>Background</h3> GCC19CART, the first clinical candidate from the CoupledCAR® solid tumor platform, targets guanylate cyclase-C (GCC) which is expressed in colorectal cancers. CoupledCAR utilizes multiple vectors to make both solid tumor targeting CAR-T and CD19 CAR-T in a single manufacturing step. An investigator-initiated dose escalation trial in China for patients with relapsed or refractory metastatic colorectal cancer (R/R mCRC) is reported here. <h3>Methods</h3> Subjects are screened for GCC expression by immunohistochemistry. Eligible subjects undergo leukapheresis, a single dose of lymphodepleting chemotherapy (fludarabine 30mg/m² and cyclophosphamide 300mg/m²) 3 days prior to infusion, and then administration of a single infusion of GCC19CART at one of two preassigned doses: 1x10⁶ or 2x10⁶ CAR T-cells/kg. Endpoints are safety and preliminary evidence of efficacy as determined by CT or PET/CT per RECIST 1.1 or PERCIST 1.0. All responses were confirmed by an independent third-party imaging contract research organization (CRO). <h3>Results</h3> 13 subjects have been enrolled to dose level 1 (1x10⁶ cells/kg) and 8 subjects have been enrolled to dose level 2 (2x10⁶ cells/kg). The most common adverse events were cytokine release syndrome (CRS) in 21/21 subjects (Grade 1 19/21 (90.48%) or Grade 2 2/21 (9.52%)) and diarrhea in 21/21 subjects (Grade 1 6/21 (28.57%) Grade 2 5/21 (23.81%) Grade 3 9/21 (42.86%) or Grade 4 1/21 (4.76%)). All patients with grade 3 and higher side effects were well managed. Immune effector cell-associated neurotoxicity syndrome(ICANS) was observed in 2/21 (9.52%) subjects at Grade 3 or 4 and resolved with corticosteroids. The combined overall response rate (ORR) for both dose levels was 28.6% (6/21). For dose level 1, the overall response rate (ORR) per RECIST 1.1 was 15.4% (2/13). Two subjects demonstrated a partial response (PR) while 3 additional subjects had partial metabolic response (PMR) on PET/CT with stable disease (SD) or progressive disease (PD) per RECIST 1.1. For dose level 2, The ORR per RECIST 1.1 was 50% (4/8). 4 subjects demonstrated a PR (3 at month 1, 1 at month 3 after being SD at month 1) and 2 additional subjects had PMR on PET/CT with SD per RECIST 1.1. <h3>Conclusions</h3> Preliminary results demonstrate that GCC19CART has meaningful dose-dependent clinical activity and an acceptable safety profile in relapsed or refractory metastatic colorectal cancer. This trial is ongoing and updated data will be presented. A Phase 1 trial of GCC19CART in the US has opened for accrual and is expected to enroll patients in mid-2022.","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"74 a-TIGIT mAb belrestotug in combination with anti-PD1 induces an immunocompetent tumor microenvironment (TME)","authors":"Julia Cuende, Stephanie Ma, Iain Welsby, Nicolas Rosewick, Noemie Wald, Anais Vezzu, Marjorie Mercier, Paola Tieppo, Bart Claes, Yvonne McGrath, Olivier De Henau, Gregory Driessens, Maurizio Ceppi, Marion Libouban","doi":"10.1136/jitc-2023-sitc2023.0074","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0074","url":null,"abstract":"<h3>Background</h3> T cell immunoglobulin and ITIM domain (TIGIT) is an immune checkpoint inhibitor expressed mainly on NK and T cell populations. Antagonist a-TIGIT mAbs in combination with a-PD(L)-1 demonstrated clinical proof of concept in 1L NSCLC.^{1 2} Belrestotug (previously known as EOS-448 or GSK4428859A) is an antagonistic anti-TIGIT human immunoglobulin G1 (hIgG1) antibody, designed to prevent ligand binding and to engage Fc gamma receptors (FcγR), resulting in a multifaceted mode of action: (i) activate effector T cells and NK cells (ii) modulate antigen-presenting cells, and (iii) deplete suppressive regulatory T cells (Tregs) as well as terminally exhausted CD8 T cells that express the highest levels of TIGIT.^3–5 In a first-in-human trial, belrestotug demonstrated a good tolerability profile with early signs of efficacy⁶ and we reported for the first time intratumoral TIGIT target engagement in the patient tumors.⁵ Belrestotug is currently being tested in combination with anti-PD1 in solid tumors. <h3>Results</h3> Pharmacodynamic assessment made by flow cytometry in the blood of patients treated with belrestotug in monotherapy and in combination with anti-PD1 (pembrolizumab or dostarlimab) showed (i) increased proportion of proliferating memory CD8+ T and NK cells during the first treatment cycle, (ii) sustained depletion of immunosuppressive Tregs, and (iii) decreased proportion of TIGIT high CD8+ T cells. We demonstrated the terminally exhausted phenotype of the TIGIT high CD8+ T cells targeted by belrestotug by isolating peripheral blood mononuclear cells (PBMCs) from treatment naïve cancer patients. Tregs in the tumor microenvironment (TME) hinder effective tumor immune response and are mainly localized in the stromal area. Stromal Tregs co-expressing several immune checkpoint inhibitors, including TIGIT, have a high immunosuppressive profile and its density is associated with poor clinical outcome.⁷ We investigated the functional effect of belrestotug combined with anti-PD1 on the TME using a multiplex immunofluorescence (mIF) panel. We observed a decrease of immunosuppressive TIGIT+ Tregs and PD1+ Tregs in the stroma, as well as a spatial reorganization. <h3>Conclusions</h3> Overall, our data suggests a mechanism whereby belrestotug in combination with anti-PD1 induces a more immunocompetent TME driven by immunosuppressive Treg depletion. These data support the clinical development of the doublet therapy to enhance an anti-tumor immune response. <h3>References</h3> Cho BC, <i>et al.</i> Abstract #LBA2 ESMO-IO; 2021 Jonhson ARC-7 ASCO Dec 2022 Yu X, <i>et al</i>, <i>Nature</i>, 2008 Preillon J, <i>et al. Mol Cancer Ther</i>, 2021. Cuende, <i>et al. AACR</i> 2022 Van den Mooter TF, <i>et al.</i> Abstract #CT118 AACR; 2021 Devi-Marulkar, <i>et al</i>, <i>comms Bio</i>, 2022","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"1422 Th1-specific TROP2 vaccine (AST-07X) elicits strong antigen-specific T cell responses<i>in vitro</i>","authors":"JinHo Kang, Hyo-Hyun Park, Jin Kyeong Choi, Eunkyo Joung, Hun Jung","doi":"10.1136/jitc-2023-sitc2023.1422","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.1422","url":null,"abstract":"<h3>Background</h3> Th-Vac^® discovery platform, consists of module 1 (Immunoinformatics-based <i>in-silico</i>) and module 2 (<i>in-vitro</i> and vaccine efficacy evaluation) under the comprehensive immunologic algorithms, is aimed to identify antigen-specific MHC class II epitopes for CD4⁺ T cell with optimal binding affinity and promiscuity across multiple alleles. In a therapeutic cancer area, Th1-specific epitopes prediction followed by cancer vaccine discovery is fully applicable.^1–3 Therefore, an immunological mode of action of cancer vaccine powered by Th-Vac^® discovery platform is to generate the inflammatory T-cell immunity (type 1 immunity) against tumor antigens with enough potency to overcome either the absence of a T-cell immune response to the tumor or a preexisting immune tolerant response which tends to be the immune-suppressing (type 2 immunity) phenomenon. TROP2 protein is a transmembrane glycoprotein encoded by the Tacstd2 gene. It is known to be overexpressed on the surface of various epithelial cancer cells, including prostate cancer, colorectal cancer, pancreatic cancer, and ovarian cancer, although the role of TROP2 protein in cancer cell growth and proliferation is not well understood.⁴ In this study, Th1-specific TROP2 epitopes were precisely identified via module 1 and 2 of Th-Vac^® discovery platform. <h3>Methods</h3> MHC class II binding epitope predictions were conducted thru engaging common human MHC class II alleles in module 1 of Th-Vac^® discovery platform, and MHC class II-specific peptide sequences (up to 15 mers) were initially selected based on the rank order of the predicted binding affinity which are representing potential immunogenic hot spots to MHC class II. Each peptides were synthesized to be stepping into <i>in-vitro</i> immunologic assessment (module 2 of Th-Vac^® discovery platform). Th1-specific immunologic response was evaluated with ELISpot and/or FACS analysis. <h3>Results</h3> In a module 1 of Th-Vac^® discovery platform, 10 sequences (consists of 15 mers) were finally predicted as potential epitopes that have a high-affinity to MHC class II. In module 2 (2a for <i>in-vitro</i> and 2b for <i>in-vivo</i> immunologic evaluation), four epitopes out of 10 epitopes showed only strong Th1 immune responses without type 2 immunity in both ELISpot and FACS analysis. <h3>Conclusions</h3> TROP2 epitopes that were identified in the Th-Vac^® discovery platform has been developed as a promising ‘off-the-shelf’ type Th1-specific therapeutic cancer vaccine (AST-07X). Additionally, the Th-Vac^® platform were fully validated in terms of performance and its application would be expanded beyond a cancer vaccine. <h3>References</h3> Watt WC, Cecil DL, Disis ML. Selection of epitopes from self-antigens for eliciting Th2 or Th1 activity in the treatment of autoimmune disease or cancer. <i>Semin Immunopath","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"1411 Feasibility, safety, and efficacy of personal vaccines consisting of autologous dendritic cells loaded<i>ex vivo</i>with autologous tumor antigens from self-renewing cancer cells","authors":"Robert O Dillman, Gabriel I Nistor, Hans S Keirstead","doi":"10.1136/jitc-2023-sitc2023.1411","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.1411","url":null,"abstract":"<h3>Background</h3> Personal therapeutic cancer vaccines consisting of autologous dendritic cells (DC) loaded <i>ex vivo</i> with autologous tumor antigens (ATA) derived from cells that are self-renewing in culture (cancer-initiating cells, stem cells) have been clinically tested for more than 20 years. The current study addressed feasibility, safety, and efficacy of the DC-ATA approach. <h3>Methods</h3> ATA, as irradiated tumor cells (ITC) or ITC lysates, were derived from short-term tumor cell lines established from resected cancer tissue. Peripheral blood monocytes (MC) were collected by leukapheresis; MC were differentiated into DC by culturing with interleukin-4 and granulocyte-macrophage colony-stimulating-factor (GM-CSF). Cryopreserved doses were thawed, suspended in 500 mcg GM-CSF, and injected at weeks 1, 2, 3, 8, 12, 16, 20, and 24. Data was derived from clinical trials conducted during 2000–2023 in patients with metastatic renal, hepatocellular, and ovary cancers, melanoma, and glioblastoma (GBM). Key end-points were DC-ATA manufacturing success rates, treatment emergent adverse events (TEAE), objective response rates, progression-free survival (PFS) and overall survival (OS). <h3>Results</h3> The success rate for establishing tumor cell lines in proprietary stem cell media was 173/178 (97.2%) including 80/82 GBM, 73/75 ovary, 17/18 liver, 3/3 other. During 2002–2023, leukapheresis procedures yielded sufficient monocytes in 218/223 patients (97.8%) including 74/74 melanoma, 72/74 GBM, 50/53 ovary, 11/11 renal cell, 8/8 hepatoma, and 3/3 other. Of 187 treated patients, no one discontinued DC-ATA because of TEAE; there were no grade 4 TEAE. Most common TEAE were mild to moderate, self-limited local injection site reactions and flu-like symptoms. There was no difference in TEAE frequency or grade in a blinded, randomized trial of DC-ATA vs MC in ovary patients. Immune responses were more favorable for DC-ATA vs ITC in metastatic melanoma, and for DC-ATA vs MC in advanced ovary cancer. During treatment there were no objective responses among 30 patients with measurable metastatic disease, but 3 (10%) had delayed, durable, complete remissions (2 renal, 1 melanoma). In GBM PFS of 10.4 months was 50% longer than in standard treatment arms of six randomized trials. In metastatic melanoma DC-ATA was associated with better OS compared to historical treatment with ITC vaccine (median 60 vs 20.4 months, p<0.001), and better OS compared to ITC in a randomized trial (43.4 vs 20.5 months with a 70% reduction in death p=0.0053) <h3>Conclusions</h3> This DC-ATA approach is feasible and reproducible across tumor types, treatment is well-tolerated, and there is efficacy in some patients. Additional investigation is warranted. <h3>Trial Registration</h3> Clinicaltrials.gov: NCT00014131, NCT00012064, NCT00436930, NCT00331526, NCT03400917 <h3>Ethics Approval</h3> All clinical studies obtained approvals from local ethics committees or institutional review bo","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"418 The development of ‘off-the-shelf’ manufacturing strategies of iPSC-based gamma-delta T cells","authors":"Yanjie Li, Lei Ding, Jixue Li, Mariska Ter Haak, Kate Rochlin, Lawrence Lamb","doi":"10.1136/jitc-2023-sitc2023.0418","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0418","url":null,"abstract":"<h3>Background</h3> Gamma-delta (γδ) T cells are depleted during cancer progression resulting in the progressive loss of anti-cancer activity. Elevated numbers of γδ T cells are associated with greater survival outcomes in both hematopoietic and solid malignancies. Induced pluripotent stem cell (iPSC) derived γδ T cells could address the therapeutic challenges of multiple allogeneic γδ T cell infusions as iPSCs possess nearly unlimited self-renewal and multi-lineage differentiation potential. These can be genetically modified, selected, and propagated to provide a source of potentially ‘off-the-shelf’ immune cells. <h3>Methods</h3> Precursor cells obtained from healthy volunteer donors were reprogrammed into iPSCs using non-integrating Yamanaka factors. A feeder-free multi-step strategy was used to differentiate iPSCs, leading to the generation of Vδ1+ γδ T cells. Characterization of the Vδ1+ T cell product included multiplex genomic PCR assays and Sanger sequencing to examine the rearrangement of the TCRγ and TCRδ gene loci, and G-band karyotype analysis. Pluripotent markers (Tra-1–60, OCT3/4 &amp; SSEA4), HPC markers (CD34, CD43), γδ T cell surface markers (CD3, γδ TCR, CD4, CD8, CD16, CD56), effector memory markers (CD45RA, CD27), natural cytotoxicity receptors (NKG2D) were identified using multiparameter flow cytometry. T cell function was determined by flow cytometric cytotoxicity assays against K562, OLM13, U87MG, OVSAHO, OVCAR-3, KURAMUCHI targets at increasing Effector to Target (E:T) ratios. Th1/2/17 cytokine release was determined following PMA/ionomycin stimulation and LEGENDplex™ bead-based immunoassays. <h3>Results</h3> We generated Vδ1T-iPSC lines (iVδ1T) identified as Vγ5-to-Jγ1/2 and Vδ1-to-Jδ1 recombination. One iPSC line showed normal karyotype with 99% cells expressing OCT3/4 &amp; SSEA4. The differentiation process generated 70+ million iVδ1T cells from 3 million iPSCs expressing γδ T cell markers CD45, CD3, Vδ1-TCR, CD16, CD56, NKG2D, CD45RA, and CD27. Cytokine release following PMA/ionomycin stimulation showed increases of at least 50x for Granzyme A, 300x for IFN-γ, 1400x for TNF-α, ~10 to 20x for Granzyme B, ~5 to 10x for Perforin, ~6x for Granulysin. IL-6 was not detected either before or after stimulation, and IL17A was at low concentration. At a 16:1 E:T ratio, preliminary data shows that Vδ1+ γδ T cells killed K562 (CML) 95.7%; MOLM13 (AML) 60.3%; U87MG (glioblastoma) 70.3%; and ovarian cancer lines OVSAHO 57.1%, OVCAR-3 69.6%, and KURAMUCHI 55.1%. <h3>Conclusions</h3> We generated Vδ1+ iPSC derived γδ T cells with effector cytokine phenotype and low risk for cytokine release syndrome. Robust cytotoxic activity was seen across a variety of cancer cell lines, potentially providing an off-the-shelf platform for allogeneic cell therapy.","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"69 A novel protease-free method for the co-detection of RNA and protein biomarkers using the RNAscope™ technology","authors":"Laetitia Chatelain, Anji Bei, Nancy George, Ge-Ah Kim, Sonali Deshpande, Steve Zhou, Li-Chong Wang, Maithreyan Srinivasan","doi":"10.1136/jitc-2023-sitc2023.0069","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0069","url":null,"abstract":"<h3>Background</h3> Spatial biology methods are increasingly used for the characterization of complex tissue microenvironments, the understanding of which can shed light on fundamental biological mechanisms and better inform development of targeted therapeutics. RNAscope™ <i>in situ</i> hybridization (ISH) technology, capable of highly sensitive single-molecule RNA detection, can be combined with immunohistochemistry (IHC) or immunofluorescence (IF) for the co-detection of clinically relevant biomarkers on the same slide with morphological context. This application is especially important in immuno-oncology research to profile immune cell populations using protein markers and characterize their activation states by detecting cytokine and chemokine expression with RNA. However, RNAscope necessitates the use of proteases to digest RNA-associated proteins and facilitate probe access to RNA targets, which can negatively impact epitopes targeted by some antibodies. Previously, we developed the Integrated Co-detection Workflow (ICW) to partially solve this problem, with the fixation of the primary antibody-target complex prior to the protease application. While ICW rescues signal for many previously incompatible antibodies, proteases can still adversely impact some of the primary antibody-target complex. To address this deficiency, we have developed a novel RNA-protein co-detection workflow that eliminates the need for protease, resulting in high detection sensitivities for both protein and RNA markers. <h3>Methods</h3> To maintain the same RNA detection sensitivity without the use of proteases, we formulated a new protease-free pretreatment buffer to replace the existing protease step within the current workflow which allows adequate accessibility of RNAscope™ probes to the target RNAs. Following this protease-free pretreatment, tissue specimens were assayed with RNAscope Multiplex to detect RNA species in the tissue, followed by standard IF staining to co-detect protein biomarkers. Antibodies which previously exhibited degraded protein signal in both sequential ISH-IF and ICW were tested in the new protocol. <h3>Results</h3> Here, we present results from FFPE human tissues to co-detect several protease-sensitive antibodies, including degranulating cytotoxic lymphocyte marker CD107a along with human house-keeping genes <i>TBP</i>, <i>POLR2A</i> and <i>PPIB</i>. The protease-free RNAscope co-detection workflow restored the protein staining pattern at nominal antibody concentrations used for IHC while maintaining mRNA dot counts for <i>TBP</i>, <i>POLR2A</i> and <i>PPIB</i>, indicating minimal impact of protease-free pretreatment buffer on both RNA and protein signal. <h3>Conclusions</h3> The protease-free RNAscope co-detection workflow will serve as a powerful multi-omics staining technique for a wider range of antibodies by enabling visualization of RNA-protein co-detection for the comprehensive profiling of tissue microenvironments, facilitating fast","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"47 Baseline blood DNA methylation-based immune profiles and tumor mutational burden predict survival outcomes in anti-PD-1 treated head and neck cancer patient","authors":"Ze Zhang, Kartik Sehgal, Keisuke Shirai, Rondi Butler, John Wiencke, Devin Koestler, Geat Ramush, Min Kyung Lee, Annette Molinaro, Hannah Stolrow, Lucas A Salas, Robert Haddad, Karl Kelsey, Brock Christensen","doi":"10.1136/jitc-2023-sitc2023.0047","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0047","url":null,"abstract":"<h3>Background</h3> Immune checkpoint inhibitors (ICIs) are approved to treat patients with recurrent/metastatic head and neck squamous cell carcinoma (HNSCC). However, currently approved biomarkers are limited due to the heterogeneity and availability of tumor samples. The development of peripheral biomarkers offers an alternative noninvasive approach to assess immunotherapy response. DNA methylation-based immune cell deconvolution provides opportunities for developing blood-based biomarkers to predict immunotherapy response outcomes in HNSCC. <h3>Methods</h3> Our study is an ongoing prospective multi-center study aimed at identifying blood DNA methylation biomarkers of therapy response in patients with HNSCC undergoing standard-of-care, FDA-approved ICIs. Blood was drawn prior to immunotherapy initiation. DNA isolated from these samples underwent methylation profiling using the Illumina EPIC microarray. Peripheral blood immune profiles were generated using cellular deconvolution.¹ 69 HNSCC patients with anti-PD-1 monotherapy were included (figure 1). 47 patients’ tumor samples were sequenced to evaluate tumor mutational burden (TMB) (figure 2). We investigated 48 immune variables and TMB for relation with progression-free survival (PFS) and overall survival (OS) using Cox proportional-hazard models adjusted for age, sex, and a marker for corticosteroid exposure.² 12 primary immune cell proportions and TMB were investigated for interaction. A p-value < 0.05 was used as the cut-off for statistical significance. <h3>Results</h3> In 69 patients with HNSCC who received anti-PD-1 therapy, neutrophil proportion, monocyte count, and total B cell count were associated with worse PFS outcomes while CD4T memory cell count and total T cell count were associated with better PFS outcomes (figure 3). Regarding OS, NLR, neutrophil proportion, total naïve lymphocyte proportion, monocyte count, CD4T naïve percentage, CD4T naïve to memory ratio, and T regulatory cell percentage were found to be associated with poorer survival while total CD4 T cell count, total CD4 T cell proportion, CD4 T memory cell proportion, total T cell count, lymphocyte to monocyte ratio, and total lymphocyte proportion were found to be associated with better outcomes (figure 4). Higher TMB was found to be associated with better survival outcomes. TMB exhibits significant interaction with peripheral monocyte proportion. TMB is a better predictor of survival in individuals with a lower level of monocyte proportion (figure 5). <h3>Conclusions</h3> DNA methylation-based immune profiling in peripheral blood at baseline identifies clinically relevant biomarkers of benefit from ICIs. Our results demonstrate the potential of new blood DNA methylation-based biomarkers to predict immunotherapy response prior to the initial treatment, and connected peripheral immune profile with TMB through their interactive impact on survival outcomes. <h3>References</h3> Salas LA, Zhang Z, Ko","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"1466 Galectin-1 orchestrates a hierarchical tumor to stromal extracellular vesicles system that fosters immune suppression","authors":"Camila A Bach, Ada Blidner, Ramiro Perrotta, Joaquin P Merlo, Mariana Salatino, Gabriel Rabinovich","doi":"10.1136/jitc-2023-sitc2023.1466","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.1466","url":null,"abstract":"<h3>Background</h3> Extracellular vesicles (EVs) suppress effector cells and activate immunosuppressive cells in the ‘escape phase’ of tumor immunoediting. Tumor derived EVs contribute to the differentiation and expansion of immunosuppressive cell subsets. Bone marrow-derived cells (BMDCs) can uptake EVs released by 4T1 -a triple-negative breast cancer cell line- and induce myeloid-derived suppressor cells (MDSCs).¹ Immunosuppressive myeloid cells expansion can also be promoted by their own EV in an autocrine manner. Moreover, EVs secreted by immunosuppressive myeloid cells, may inherit their parental functions.² Nevertheless, the molecular circuits and mediators of tumor microenvironment EV release remain uncertain. <h3>Methods</h3> We generated immunosuppressive myeloid cells by culturing mouse BMDCs with GM-CSF for three days in the presence of Gal1. Additionally, we cultured 4T1 WT and <i>Lgals1</i> knocked out cells. We purified Small EVs by size exclusion chromatography from conditioned medium of immunosuppressive myeloid cells (control and Gal1-treated) or 4T1 cells (WT or Gal1 KO). We further purified 4T1 EVs with CD63+ beads, a tumoral EV marker. ELISA, flow cytometry, miRNA sequencing, proteomic and metabolomic analyses verified EV identity. We performed functional assays by co-culturing tumoral or myeloid EVs with BMDC, activated T or B cells. <h3>Results</h3> When exposed to EVs from 4T1 cells <i>in vitro</i>, BMDCs switched their differentiation pathway to a M-MDSCs phenotype (CD11b⁺Ly6G^-Ly6C^hi) and showed higher immune checkpoint molecules expression, including PD-L1 (p=0.005) and VISTA (p=0.003). However, when exposed to tumoral EVs lacking Gal1, BMDCs reinforced a PMN-MDSCs phenotype (CD11b⁺Ly6G⁺Ly6C^lo). In contrast with Gal1⁺ EVs, tumoral EVs lacking Gal1 failed to inhibit CD4⁺ and CD8⁺ T and B cell proliferation and activation. Gal1 is both in the cargo and corona of 4T1 EVs as revealed by flow cytometry and ELISA (p=0.0032). Moreover, EV production inhibition with GW4869 in 4T1 cells decreased Gal1 levels secreted (p=0.037). To analyze EV-derived Gal1 contribution as an MDSC autocrine signal, we added EVs from Gal1-treated immunosuppressive myeloid cells to new BMDCs and observed CD11b⁺ cells expansion and higher VISTA expression on cells with M-MDSCs phenotype. Moreover, these EVs showed greater T cell-suppressive capacity and has different protein, metabolic, and miRNA cargo compared to control EVs. <h3>Conclusions</h3> Here, we propose that Gal1⁺ EVs released by tumoral cells interact with myeloid cells and potentiate their immunosuppressive properties, including the release of EV with autocrine and paracrine functions. Targeting Gal1 as a molecular mechanism of EV-mediated tumor development may help overcome therapy resistance. <h3>References</h3> Xiang X, Poliakov A, Liu C, Liu Y, D","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"1397 CDR404, an antibody-based bispecific &amp; bivalent T-cell engager targeted against MAGE-A4, for Squamous Non-Small Cell Lung Cancer (SQ-NSCLC)","authors":"Melissa Vrohlings, Stephanie Jungmichel, Ivana Tosevski, Alessio Vantellini, Philip Knobel, Nadia Sanchez, Elizabeth Ross, Marian Van Kerckhoven, Giorgia Giacomazzi, Maria Liivrand, Reija Hieta, Nicholas Dupuis, Dieter Rondas, Pamela Swatkowski, Daniel Lenherr-Frey, Swethajit Biswas, Gilberto Lopes, Leonardo Borras","doi":"10.1136/jitc-2023-sitc2023.1397","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.1397","url":null,"abstract":"<h3>Background</h3> Squamous non-small cell lung cancer (SQ-NSCLC) is the 2^nd most common type of lung cancer. Given the paucity of actionable oncogene drivers, and lack of efficacy from multiple therapies in the Lung-MAP trial, there is a high unmet need in SQ-NSCLC to develop effective 2^nd-line immunotherapies for patients with disease progression after immune checkpoint inhibitors (ICI). The melanoma antigen gene A4 (MAGE-A4) is exclusively expressed in cancer and absent in somatic tissues. MAGE-A4-derived peptides presented on HLA molecules at the cell surface recently emerged as a novel therapeutic opportunity. Thus, the two key objectives of this study were to: 1). Evaluate MAGE-A4 expression in human SQ-NSCLC; 2). Demonstrate the anti-cancer activity of CDR404, an antibody-based bispecific and bivalent T-cell engager targeted against MAGE-A4_230–239 peptide <i>in vitro</i> and <i>in vivo</i> xenograft models of SQ-NSCLC. <h3>Methods</h3> MAGE-A4 mRNA prevalence and expression in SQ-NSCLC was analyzed using the TCGA database (https://www.cancer.gov/tcga). Protein expression of MAGE-A4 was confirmed using immunohistochemistry (IHC) in fifty FFPE human SQ-NSCLC samples (clone E7O1U). CDR404 target cell killing in the presence of human PBMCs was assessed using the human SQ-NSCLC cell line NCI-H1703. HLA-A*02:01⁺MAGE-A4^neg cancer cells were used as controls. To exclude reactivity of CDR404 in healthy tissues, HLA-A*02:01⁺ primary cells presenting peptides with high MAGE-A4 similarity were co-cultured with human PBMCs. <i>In vivo</i> activity of CDR404 in SQ-NSCLC was evaluated with an NCI-H1703 xenograft model in NSG mice. <h3>Results</h3> SQ-NSCLC had the highest MAGE-A4 mRNA expression levels among solid cancers in the TCGA database. IHC showed positive MAGE-A4 staining in 28/50 (56%) of SQ-NSCLC samples. <i>In vitro</i>, CDR404 showed efficient target cell lysis across all effector-to-target ratios tested. Similarly, simultaneous target engagement and resulting synapse formation induced T cell activation and secretion of cytolytic molecules in an effector-to-target ratio-dependent fashion. No reactivity was observed using co-cultured HLA-A*02:01⁺MAGE-A4^neg cancer cells. Lack of T cell activation/cytolytic molecule release in the presence of HLA-A*02:01⁺ primary cells confirmed the specificity profile of CDR404. <i>In vivo</i>, treatment with four different doses of CDR404 induced complete tumor regression in the SQ-NSCLC NCI-H1703 xenograft model. <h3>Conclusions</h3> The high MAGE-A4 expression levels and the highly specific anti-cancer cell activity of CDR404 make it a highly attractive immunotherapy for development post-progression on ICI for patients with HLA-A*02:01+ SQ-NSCLC. A multi-tumor phase 1 trial of CDR404, including SQ-NSCLC, is expected to begin in 2024 with prospective patient selection for both HLA-A*02:01 and tumor MAGE-A4. <h3","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}