Regular and Young Investigator Award Abstracts最新文献

{"title":"1345 mTFF2-MSA (mTNX-1700) suppresses tumor growth and increases survival in anti-PD-1 treated CT26.wt subcutaneous and CT26-Luciferase orthotopic syngeneic colorectal cancer models by targeting MDSCs","authors":"Bruce L Daugherty, Rebecca J Boohaker, Rebecca Johnstone, Karr Stinson, Grace Zhao, Mingfa Zang, Jin Qian, Timothy C Wang, Seth Lederman","doi":"10.1136/jitc-2023-sitc2023.1345","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.1345","url":null,"abstract":"<h3>Background</h3> Myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment are potential therapeutic targets in immune checkpoint cancer therapy, particularly for cancers that are unresponsive to anti-PD-1 therapy. It has previously been demonstrated that trefoil factor family 2 (TFF2), a secreted anti-inflammatory peptide, can partially suppress MDSC expansion and activate tumor immunity through agonism of the CXCR4 receptor.^1–3 We investigated whether a novel fusion protein, murine TFF2-murine serum albumin (mTFF2-MSA), has single agent activity and can improve on the therapeutic effects of anti-PD-1 in CT26.wt subcutaneous and CT26-Luciferase (CT26-Luc) orthotopic syngeneic mouse models of advanced colorectal cancer (CRC). <h3>Methods</h3> Two syngeneic colon carcinoma mouse models were developed using the CT26.wt and CT26-Luc CRC cell lines grafted subcutaneously and orthotopically, respectively, into BALB/C mice. We generated a recombinant fusion protein, designated mTFF2-MSA, which contains murine TFF2 fused to murine serum albumin (MSA), for the purpose of increasing half-life and reducing the frequency of dosing. Mice subsequently received mTFF2-MSA, anti-PD-1 antibody (clone 29F.1A12 for subcutaneous study; clone RMP-1–14 for orthotopic study) or combination of mTFF2-MSA and anti-PD-1. Tumor volume, and survival were measured. At the endpoint, flow cytometry was performed on the blood, bone marrow, tumor, and lymph nodes, to examine treatment-induced effects on cellular immune profiles. <h3>Results</h3> In the CT26.wt model, tumor growth was suppressed by mTFF2-MSA, anti-PD-1 and by the combination of mTFF2-MSA/anti-PD-1 by 16%, 40% and 60%, respectively. Survival in the CT26.wt model on Day 30 treated with vehicle, mTFF2-MSA, anti-PD1 and the combination of mTFF2-MSA and anti-PD-1 was 0%, 40%, 60% and 60%, respectively. In the CT26-Luc model, mTFF2-MSA, anti-PD-1, and the combination of mTFF2-MSA and anti-PD-1 suppressed tumor growth by 42%, 94%, and 94%, respectively. In the CT26-Luc model, neutrophils were significantly reduced in the blood in all treatment groups by flow cytometry. In the bone marrow, a significant reduction in total macrophages, M2 macrophages, and neutrophils was also observed but only in the group treated with anti-PD-1/mTFF2-MSA. In the axillary lymph node, there was a significant reduction in TOX+ cells in both CD4+ and CD8+ T-cells in all treatment groups. In the tumor, there was a significant reduction in total macrophages and M2 macrophages in all treatment groups, while NK cells were also increased, but only in the combination anti-PD-1/mTFF2-MSA treated group. <h3>Conclusions</h3> mTFF2-MSA has single agent activity and is additive to anti-PD-1 antibody checkpoint inhibition in treating two syngeneic (subcutaneous and orthotopic) mouse models of advanced colorectal cancer. <h3>References</h3> Dubeykovskaya Z, Dubeykovskiy A, Solal-Cohen J, Wang TC. Secreted trefoil factor 2 activa","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"60 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161405","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":"1377 Messenger RNA nanoparticles targeting fusion-driven malignancies","authors":"Sadeem Qdaisat, Leighton Elliott, Dingpeng Zhang, Hector Mendez-Gomez, Study Staff, Elias Sayour","doi":"10.1136/jitc-2023-sitc2023.1377","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.1377","url":null,"abstract":"<h3>Background</h3> Gene-fusion genetic aberrations present unique challenges in cancer diagnosis and management. Current treatment strategies often yield low efficiency due to their non-specific targets leading to adverse side effects. Personalized immunotherapies targeting these genetic aberrations can potentially improve therapeutic outcomes. We proposed to create messenger RNA nanoparticles designed to target fusion-driven malignancies, aiming to enhance treatment specificity and minimize classic immunotherapeutic adverse effects. <h3>Methods</h3> We are developing a pipeline to identify gene-fusions, design amplification primers, and classify fusions for treatment using messenger RNA nanoparticles cancer vaccine.^1–5 The immunogenicity and safety of this approach are to be evaluated using murine models and spontaneous canine and feline tumors. <h3>Results</h3> We demonstrated the synthesis of fusion-specific mRNA and identified common fusion breakpoints in various tumor types, such as Ewing sarcoma, glioblastoma, ependymoma, non-small cell lung carcinoma, and clear cell sarcoma. Importantly, we established two primary approaches for our fusion-based messenger RNA nanoparticles: 1) off-the-shelf gene-fusion immunotherapy vaccines, and 2) personalized vaccines developed for rare fusions. <h3>Conclusions</h3> Preliminary findings suggest that our formulation can target gene fusions with potentially improved treatment. <h3>References</h3> Sayour EJ, Grippin A, De Leon G, Stover B, Rahman M, Karachi A, <i>et al</i>. Personalized Tumor RNA Loaded Lipid-Nanoparticles Prime the Systemic and Intratumoral Milieu for Response to Cancer Immunotherapy. <i>Nano Lett</i>. 2018. Sayour EJ, De Leon G, Pham C, Grippin A, Kemeny H, Chua J, <i>et al</i>. Systemic activation of antigen-presenting cells via RNA-loaded nanoparticles. <i>OncoImmunology</i>. 2016:e1256527. Sanchez-Perez LA, Choi BD, Archer GE, Cui X, Flores C, Johnson LA, <i>et al</i>. Myeloablative temozolomide enhances CD8(+) T-cell responses to vaccine and is required for efficacy against brain tumors in mice. <i>PLoS One</i>. 2013;<b>8</b>(3):e59082. Mitchell DA, Fecci PE, Sampson JH. Immunotherapy of malignant brain tumors. <i>Immunol Rev</i>. 2008;<b>222</b>:70–100. Badapanda C. Suppression subtractive hybridization (SSH) combined with bioinformatics method: an integrated functional annotation approach for analysis of differentially expressed immune-genes in insects. <i>Bioinformation</i>. 2013;<b>9</b>(4):216–21. <h3>Ethics Approval</h3> All animal experiments were conducted following protocols approved by the Institutional Animal Care and Use Committee at the University of Florida (protocol number <b>202009685</b>).","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"60 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161408","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":"477 A novel antibody targeting human monocyte-intrinsic PD-L1 promotes immune stimulatory functions of monocytes for antitumor immunity","authors":"Michelle Hsu, Xin Liu, Ying Li, Jacob Hirdler, Fabrice Lucien-Matteoni, Haidong Dong","doi":"10.1136/jitc-2023-sitc2023.0477","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0477","url":null,"abstract":"<h3>Background</h3> Current PD-L1 targeting antibodies have been developed to block PD-L1’s interaction with PD-1, thereby preventing inhibition of T cell cytotoxicity. However, there has been limited clinical success in the treatment of cancers, despite high expression of PD-L1. Recent reports have demonstrated that tumor-intrinsic PD-L1 can signal intracellularly to promote cell survival independent of PD-1 ligation, potentially explaining why some cancer patients do not respond to immune checkpoint therapies. Besides tumor cells, host myeloid cells are sources of PD-L1 and can be highly immunosuppressive. Unfortunately, the intrinsic functions of PD-L1 in myeloid cells has not been well studied. We aim to dissect the intrinsic signaling of PD-L1 in monocytes, a subset of myeloid cells, and to investigate how this may be impairing antitumor immunity. <h3>Methods</h3> Our lab has identified a new PD-L1 antibody (clone H1A), which destabilizes PD-L1 at the cell surface and induces its degradation. In our experiments, we used human PBMCs isolated from healthy donor blood and isolated monocytes from PBMCs using negative magnetic selection. To study the effects H1A-induced PD-L1 degradation on human monocytes, we assessed monocyte phenotype, function, and transcriptional profile by flow cytometry, immunoassays, and single-cell RNA sequencing, respectively. To study the indirect effects of H1A on T cell functional states, we evaluated PBMCs by flow cytometry and mass cytometry using T cell focused panels. To evaluate T cell function, we used cytotoxic killing assays. <h3>Results</h3> H1A-treated monocytes resulted in decreased total expression of PD-L1 and a transient increase of CCL2 secretion across multiple donors. H1A treated monocytes had greater polyfunctionality based on the number of analytes secreted by single cells. H1A treated monocytes had significant transcriptional profile changes, related to transcriptional activation of CCL2. PBMCs treated with H1A resulted in more effector CD8 T cell and less regulatory T cell populations. Finally, H1A treatment of PBMCs resulted in greater T cell-mediated killing of tumor cells <h3>Conclusions</h3> Our data suggests monocyte-intrinsic PD-L1 signaling inhibits transcriptional activation and subsequent secretion of CCL2 in human monocytes, thereby restricting effector T cells populations. H1A antibody abolishes this inhibitory mechanism and restores effector T cell responses. The significance of our studies contributes to understanding a new mechanism of action of PD-L1 in monocytes that may cause cancer patients to not respond to anti-PD-1/PD-L1 therapy. The H1A antibody provides a new tool that can overcome these limitations to enhance T-cell mediated antitumor immunity and prolong survival of patients with lethal cancers.","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"8 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161423","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":"61 Treatment-specific immune phenotypes in PBMCs revealed by nELISA high-throughput proteomics","authors":"Nathaniel Robichaud, Grant Ongo, Woojong Rho, Ivan Teahulos, Milad Dagher","doi":"10.1136/jitc-2023-sitc2023.0061","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0061","url":null,"abstract":"<h3>Background</h3> High-throughput screening (HTS) programs are increasingly adopting high-content technologies that can better inform the selection of drug candidates early on in the pipelines. For cancer immunotherapy, proteomics tools to investigate interactions between cancer and immune cells compromise either content or cost, limiting access to phenotypic data. The affordable gold-standard in proteomics, the ELISA, has proven difficult to scale. At fault has been the cross-reactivity between ELISA reagents when multiplexing beyond a few dozen antibody pairs. Here, we describe the nELISA: a massively-parallelized high-throughput miniaturized ELISA with a content, cost and throughput amenable to HTS, and demonstrate its applicability to characterize immune phenotypes in co-culture systems. <h3>Methods</h3> To overcome the long-standing cross-reactivity issue, the nELISA uses DNA oligos to pre-assemble each pair of antibodies onto a spectrally barcoded microparticle set. The resulting reagents are fully-integrated nELISA sensors that can be read-out on commercial cytometers, enabling highly-multiplexed and high-throughput analysis. Using this approach, we developed a comprehensive inflammatory panel containing 191 cytokines, chemokines, proteases, growth factors, and soluble receptors. Our results show that the nELISA can maintain single-plex specificity, sensitivity, and quantification as content is scaled to 191-plex. Furthermore, the nELISA performs at a throughput of 1536 samples/cytometer/day, yielding &gt;300,000 data points in a single day, at a cost amenable to high-throughput screening. <h3>Results</h3> To demonstrate the nELISA’s utility in HTS, we ran the largest PBMC secretome screen to date, in which &gt;7000 PBMC samples were treated with various inflammatory stimuli, and further perturbed with a selected library of 80 recombinant protein ‘perturbagens’. 191 secreted proteins were profiled in all samples, resulting in ~1.4M datapoints (figure 1A). The nELISA profiles were able to capture phenotypes associated with specific stimulation conditions, individual donors, and potent cytokine perturbagens. By compensating for stimulation and donor differences, we clustered perturbagens according to their effects on PBMC secretomes, identifying well-established cell responses such as Th1 or Th2. Novel phenotypic effects were also identified, such as distinct responses to the near identical CXCL12 alpha and beta isoforms (figure 1B). Interestingly, we observed important similarities between PBMC responses to the cytokine drugs IFN beta and IL-1 Receptor antagonist, supporting the use of anakinra as a replacement for IFN beta in certain indications. <h3>Conclusions</h3> The nELISA captures broad secretome ranges and subtle differences in immune phenotypes, revealing critical insights in cell-based screens. Thus, the nELISA is a powerful new tool for cancer immunotherapy assays, including phenotypic screening, target identification/deconvolu","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"8 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161438","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":"29 Immune modulation and baseline biomarker correlation with clinical benefit following treatment with COM701+nivolumab+/-BMS-986207 in patients with platinum resistant ovarian cancer","authors":"Gady Cojocaru, Zoya Alteber, Assaf Wool, Adi Shuchami, Inbal Barbiro, Roy Granit, Yu Liang, Zurit Levine, Pierre Ferre, Eran Ophir","doi":"10.1136/jitc-2023-sitc2023.0029","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0029","url":null,"abstract":"<h3>Background</h3> COM701 is a 1^stin-class, T-cell checkpoint-inhibitor that binds to PVRIG, blocking its interaction with PVRL2 expressed on tumor and antigen-presenting cells. We have reported initial anti-tumor activity of COM701+nivolumab+/-BMS-986207 (anti-TIGIT) in patients with platinum-resistant ovarian cancer (PROC).^{1 2} Checkpoint inhibitors have limited activity in PROC patients, particularly in patients with reduced PD-L1 and T cell infiltration.³ Here, we present preliminary translational assessment of PROC patients treated with COM701+nivolumab+/-BMS-986207. <h3>Methods</h3> Pretreatment (n=28) and on-treatment (n=21) biopsies were collected from patients treated with COM701+nivolumab+/-BMS-986207 Q4W (NCT03667716 and NCT04570839) and subjected to IHC stain with anti-PD-L1, anti-CD8, anti-PVRL2 and anti-PVRIG. Selected biopsies were subjected to ImmunoID NeXT assay. Patient IHC data from both studies were pooled for analysis. <h3>Results</h3> Patients with PR or SD>180 days (per RECIST) were defined as having clinical benefit (CB) versus NCB patients (PD or SD<180). Clinical responses were independent of PD-L1, CD8 and PVRIG baseline expression: 3/7 CB patients had baseline PD-L1 CPS<1; median CD8 and PVRIG pre-levels were similar for both CB and NCB patients (figure 1A). In contrast, higher baseline PVRL2 H-score was correlated with response with median PVRL2 score of 290 in CB versus 240 NCB patients (p=0.05, figure 1B). Examining tumor structural genomic-variants (by exome-DNAseq) revealed one responding patient (PR) with a genomic PVRL2-amplification and baseline PVRL2 H-score of 300 (figure 2A). TCGA analysis revealed that ovarian and gastric-tumors have an amplification of PVRL2 rate of ~3–5% which is correlated with higher mRNA expression (figure 2B). Investigating immune modulation, CD8 increase was shown in 8/13 patients with paired biopsies, with a prominent increase in CB patients and trend for stronger CD8 increase in patients treated with triple versus dual blockade (figure 3). Paired TCR sequencing of three CB patients demonstrated an increase in the number of TCRb clones, where the most dominant on-treatment clones were present pretreatment and expanded in the TME following treatment (figure 4). CD8 increase demonstrated by IHC and mRNA (deconvolution-score) in a patient with PR, was accompanied by an increase in T-cell clone numbers and clonality and increase in M1 macrophages, while M2 macrophages mRNA-signature decreased (figure 5). <h3>Conclusions</h3> These results demonstrate the efficacy of COM701 treatment combinations in terms of clinical responses and immune modulation, regardless of the tumor baseline inflammatory status. In addition, the preliminary correlation between the expression of the PVRIG ligand, PVRL2, and clinical benefit may suggest the potential of baseline PVRL2 as a biomarker to enrich for responding patients. <h3>References</h3> Abstract #159P; ESMO-IO 2022 A","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161439","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":"1429 Application of ICTIS to currently recruiting clinical trials: a novel scoring system to assess the inclusivity of advanced non-small-cell lung cancer immunotherapy trials","authors":"Kira Nguyen, Ashley Wei, Wint Yan Aung, Nicole Spinelli, Nagashree Seetharamu","doi":"10.1136/jitc-2023-sitc2023.1429","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.1429","url":null,"abstract":"<h3>Background</h3> Many immunotherapy trials contain overly restrictive or irrelevant exclusionary criteria, limiting accessibility to patients and contributing to disparities in enrollment and outcomes. We developed a novel scoring system, the Immunotherapy Clinical Trial Inclusivity Scale (ICITS), to measure the inclusivity of immunotherapy clinical trials and provide recommendations for broadening eligibility criteria for future immunotherapy trials. Using ICTIS, we measured the restrictiveness of eligibility criteria across advanced non-small-cell lung cancer (NSCLC) immunotherapy clinical trials. <h3>Methods</h3> National guidelines and novel author recommendations informed ICTIS’s development, a 22-point-summative scale using a binary system awarding 1 point for the usage of each inclusive criterion. Recruiting and not-yet-recruiting NSCLC interventional U.S. trials were accessed using ClinicalTrials.gov. Trials were filtered through to identify and record eligibility criteria information on only metastatic immunotherapy NSCLC trials. Then, these trials were scored with ICTIS and compared in subgroups: year, combination treatment type, phase of trial, and line of treatment. Mean ICTIS scores were compared with ANOVA and t-tests, and individual points were compared with chi-squared tests. <h3>Results</h3> 142 out of 343 trials from ClinicalTrials.gov were metastatic and immunotherapy and scored. The majority of trials still used exclusive criteria for performance status, pneumonitis, washout period, and various organ function criteria. Through subgroup analyses, phase ½ trials were found to have significantly more exclusive psychiatric and cardiac criteria (χ2=7.3; p<0.05). Use of platelet count target was used in significantly more number of immunotherapy studies than in combination studies (χ2=5.1, p<0.01). Taking date of registration of clinical trial into consideration, we noted that leptomeningeal involvement became more inclusive over time (χ2=8.0; p<0.05). A significantly higher number of second-line trials had inclusive pneumonitis criteria (χ2=4.9; p<0.05). However, the majority of criteria were uniform different risk profiles (χ2; p>0.05). No significant differences were found between mean ICTIS scores across all subgroups (ANOVA and t-test; p>0.05). Also, a wide distribution of scores was found showing low homogeneity (figure 1). <h3>Conclusions</h3> Our results indicate that despite the release of national guidelines for improving inclusivity, immunotherapy trials have made negligible efforts to broaden their rigid eligibility criteria. Moreover, the majority of trials, irrespective of combination or monotherapies, first-line or subsequent-line, and early or late phase have homogenous criteria across various eligibility parameters. Using ICTIS, metastatic NSCLC immunotherapy trials were able to be analyzed for their inclusivity and prevalent restrictive criteria were identified for refinement. Our analysis can help investigators","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161593","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":"960 Chromium Flex enables scFFPE-Seq and single cell-spatial data integration from human tumor blocks","authors":"Tingsheng Y Drennon, Jawad Abousoud, Ryan Stott, Juan Pablo Romero, Paul Lund, Sarah Taylor, Peter Smibert, Andrew Kohlway","doi":"10.1136/jitc-2023-sitc2023.0960","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0960","url":null,"abstract":"<h3>Background</h3> FFPE tissues are the most commonly generated sample type in clinical settings. They provide valuable diagnostic information about disease etiology. However, many existing technologies for profiling gene expression at the RNA level are either incompatible with FFPE tissues due to formaldehyde crosslinking and RNA degradation or lack the ability to resolve expression patterns at single cell resolution. <h3>Methods</h3> The new and highly sensitive Chromium Single Cell Gene Expression Flex assay (Flex) from 10x Genomics uses a probe-based approach to profile the whole transcriptome in fixed samples, including FFPE tissues. The Flex assay enables single cell sequencing of FFPE tissues (scFFPE-Seq) with highly sensitive detection of whole transcriptome gene expression. <h3>Results</h3> To demonstrate the robustness of the Flex assay, we separately dissociated FFPE sections from 38 human tissue blocks containing both healthy and diseased/cancer samples derived from a variety of tissues including Alzheimer’s brain, glioblastoma, breast, colon, heart, liver, lung, ovary, prostate, and skin. Data derived from these samples provided important biological insights including distinct cell clustering along with identification of representative cell types. Additionally, consistent data quality observed across different sections from the same FFPE block highlights the reproducibility and reliability of the assay. The ability to integrate Flex single cell data with Visium CytAssist spatial data from the same FFPE block through spot deconvolution allows for a more comprehensive understanding of biology. Each spot in Visium CytAssist data may include multiple cells. Using spot deconvolution methods that annotate scFFPE data as reference, the proportion of different cell types in each Visium spot can be determined to further refine cell heterogeneity for spatial visualization. After data integration for a colon cancer sample, we identified distinct tumor stroma with plasma cells expressing MZB1 surrounding tumor regions with high expression of BRCA1, nicely overlapping the H&amp;E images. The integration of both platforms opens opportunities to leverage single cell resolution while preserving spatial context. <h3>Conclusions</h3> In summary, Chromium Single Cell Gene Expression Flex enables characterization of the biology preserved in human FFPE tumor samples at a single cell level. The assay expands the capabilities of 10x Genomics’ Chromium platform, enabling cross-assay compatibility with Visium CytAssist Spatial Gene Expression for FFPE samples and serves as a powerful tool to facilitate discoveries in disease progression and therapeutic target development.","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"24 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161598","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":"30 Molecular features associated with long survival on tebentafusp in previously untreated metastatic uveal melanoma in a phase 3 trial","authors":"Marlana Orloff, Kevin Kim, Sarah Stanhope, Adel Benlahrech, Emma Leach, Laura Collins, Koustubh Ranade, Brendan Curti","doi":"10.1136/jitc-2023-sitc2023.0030","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0030","url":null,"abstract":"<h3>Background</h3> Metastatic uveal melanoma(mUM), a rare cancer with poor prognosis, has a historical 1-yr overall survival (OS) rate of 52%. Tebentafusp, a bispecific (gp100 x CD3) ImmTAC, is approved for adult HLA-A*02:01+ patients (pts) with unresectable or mUM. In the primary analysis of the Ph3 IMCgp100–202 study in previously untreated mUM [NCT03070392], tebentafusp significantly improved OS compared to investigator’s choice (IC) [HR 0.51]. We explored molecular features in tumor biopsies and serum as predictors of long OS (≥3 years) on tebentafusp in the Ph3 study. <h3>Methods</h3> In this randomized, open-label, Ph3 trial, 1L HLA-A*02:01+ mUM pts were randomized 2:1 to receive tebentafusp or IC, stratified by LDH. Primary endpoint was OS. This analysis is based on OS Nov 2022 data cutoff. Serum cytokines were measured using a multiplex panel of 11 immune markers in 226 patients on tebentafusp and 76 on IC. Tumor biopsies were available from 176 pts on tebentafusp and 72 on IC. Biopsies were analyzed by immunohistochemistry using antibodies to gp100, CD3 and CD163 and assessed by a pathologist or quantified using digital image analysis. Sera (N=202) collected at baseline and week 9 on tebentafusp were analyzed for ctDNA using targeted mPCR-NGS assay for mutations in 15 genes including GNAQ, GNA11, SF3B1, CYSLTR2, PLCB4 and EIF1AX. <h3>Results</h3> 378 pts were randomized to tebentafusp (245) or IC, including pembrolizumab (77), ipilimumab (11) or dacarbazine (7). After a median follow-up of 22 months, the estimated 3-year OS on tebentafusp was 27% (95% CI 22–34) vs IC of 13% (95% CI 7–23). At baseline, gp100 expression in the tumor was not associated with long OS in the tebentafusp arm. Lower CD163:CD3 ratio in tumor biopsies or lower serum levels of IL6, IL10, CXCL10, CXCL11, MCP1 cytokines were associated with long OS on tebentafusp but not IC. Combination of low tumor CD163:CD3 ratio and low serum IL10 levels was most strongly associated with long OS (table 1). This subset also had long OS in the Ph2 IMCgp100–102 study enrolling 2L+ treated mUM patients (3 yr OS 46% (95% C.I. 28–74)). In the tebentafusp arm, 13/18 (72%) ctDNA evaluable pts with survival ≥3 years cleared their ctDNA at week 9 after initiation of tebentafusp, and 5/18 pts had ≥50% reduction in ctDNA. <h3>Conclusions</h3> A low immunosuppressive tumor microenvironment, low serum levels of inflammatory cytokines and ctDNA reduction by week 9 are associated with OS ≥3 years on tebentafusp in previously untreated mUM. <h3>Trial Registration</h3> NCT03070392: A Phase II Randomized, Open-label, Multi-center Study of the Safety and Efficacy of IMCgp100 Compared With Investigator Choice in HLA-A*0201 Positive Patients With Previously Untreated Advanced Uveal Melanoma <h3>Ethics Approval</h3> Institutional review board approval was obtained and all participants gave informed consent prior to enrolement.","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"11 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161612","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":"675 Safety and tolerability of magrolimab combination therapy in patients with recurrent or metastatic head and neck squamous cell carcinoma (RM-HNSCC)","authors":"A Dimitrios Colevas, Katie Kerrigan, Venessa Chin, Natalie Rainey, John Park, Bruno Fang, Diogo Alpuim Costa, José Dinis, Minh Phan, Lanjia Lin, Yiran Zhang, Siu-Chi Chang Sun, Michael Howland, Kelly Curtis, Douglas Adkins","doi":"10.1136/jitc-2023-sitc2023.0675","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0675","url":null,"abstract":"<h3>Background</h3> Novel combination therapies are needed to improve outcomes in RM-HNSCC. Magrolimab is a monoclonal antibody that blocks CD47, a ‘don’t eat me’ signal overexpressed on cancer cells. Magrolimab induces macrophage-mediated phagocytosis of tumor cells and may synergize with chemotherapy agents through enhancement of phagocytic signals. The Phase 2 ELEVATE HNSCC multicenter, open-label study (NCT04854499) is evaluating magrolimab-containing regimens in patients with RM-HNSCC (figure 1). Here, we report data from 2 safety run-ins (SRI1 and SRI2) designed to assess safety/tolerability and recommended Phase 2 dose (RP2D) of magrolimab in combination with standard of care. <h3>Methods</h3> Patients in SRI1 with previously untreated RM-HNSCC received magrolimab+pembrolizumab+platinum+5-fluorouracil; patients in SRI2 with locally advanced or RM-HNSCC (1–2 lines of prior systemic therapy) received magrolimab+docetaxel. Magrolimab was first administered as a 1 mg/kg priming dose, followed by weekly 30 mg/kg doses for two 21-day cycles and then a maintenance dose of 60 mg/kg Q3W. Pembrolizumab and chemotherapy were given per standard of care. Primary endpoints of the SRI were incidence of adverse events (AEs) and dose-limiting toxicities (DLTs). Safety was assessed in patients who received ≥1 dose of study drug. The incidence of DLTs was assessed using patients who experienced a DLT during the DLT evaluation period or who completed ≥2 magrolimab and ≥1 combination agent doses. To select an RP2D, ≤2 of 6 DLT-evaluable patients could experience a DLT, or the magrolimab dose would be de-escalated and a new cohort would be assessed. <h3>Results</h3> At least 6 patients from each SRI were considered DLT-evaluable. The safety analysis population consisted of 6 patients in SRI1 and 7 patients in SRI2. No DLTs were reported. Treatment-emergent AEs (TEAEs) occurred in 6/6 (SRI1) and 7/7 (SRI2) patients (table 1). The most common TEAEs observed in each SRI were fatigue (SRI1) and anemia (SRI2). TEAEs leading to magrolimab discontinuation occurred in 1/6 patients in SRI1 (fatigue) and 1/7 patients in SRI2 (oral cavity fistula unrelated to study drug). In SRI1, no deaths were reported; 3 deaths were reported as unrelated to study treatment and occurred after the DLT evaluation period in SRI2: oral cavity fistula, pneumonia, and disease progression (during long-term follow-up). <h3>Conclusions</h3> The observed safety profile was as expected based on the known toxicity profiles of the individual agents. Magrolimab appears tolerable in these combinations. No DLTs or treatment-related deaths occurred. Magrolimab RP2D was declared at the initial dose level tested in both SRIs. <h3>Trial Registration</h3> NCT04854499 <h3>Ethics Approval</h3> The protocol and proposed informed consent form were reviewed and approved by all relevant Institutional Review Boards, Independent Ethics Committees and/or Research Ethics Boards prior to study commencement. There is n","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"11 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161750","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":"348 TIL engineered with membrane-bound IL15 (cytoTIL15™) are enriched for tumor-associated antigen reactivity and demonstrate pharmacologically tunable expansion and persistence in the presence of TAA","authors":"Rachel A Burga, Alonso Villasmil Ocando, Arman Aksoy, Kyle Pedro, Gauri Kulkarni, Meghan Langley, Benjamin Primack, Theresa Ross, Violet Young, Jeremy Tchaicha, Jan ter Meulen, Michelle Ols","doi":"10.1136/jitc-2023-sitc2023.0348","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0348","url":null,"abstract":"<h3>Background</h3> We have previously demonstrated the successful generation of membrane-bound IL15 (mbIL15) engineered TIL (cytoTIL15™ therapy) from solid tumors, and acetazolamide (ACZ)-driven regulated expression of mbIL15 resulted in TIL persistence in an antigen-independent preclinical model (SITC 2021, 2022). Here, we evaluated the function of pharmacologically tunable mbIL15 in the setting of chronic antigen stimulation by melanoma tumor-associated antigens (TAAs), such as MART1. <h3>Methods</h3> CytoTIL15 cells were manufactured from metastatic melanoma TIL donors by introducing mbIL15 under the pharmacological control of a carbonic-anhydrase-2 (CA2) drug responsive domain (DRD) via ACZ, the stabilizing ligand, and expanded through a proprietary rapid expansion process (REP). ACZ-dependent IL15 expression and downstream signaling were assessed. In vitro, we employed peptide-loaded HLA-A*0201 T2 cells to present MART-1 to TIL for evaluation of TCR-based functionality. CytoTIL15 cells treated with 0–25 µM ACZ were stimulated with antigen twice weekly over 28 days, with routine assessments of cell health, phenotype, cytokine production, and gene expression. In vivo, antigen-independent cytoTIL15 cell persistence in response to ACZ doses was evaluated after adoptive transfer of the TIL into immunodeficient NSG mice. <h3>Results</h3> Compared to unengineered TIL, generation of cytoTIL15 therapy from melanoma-derived TIL led to an overall 2.3-fold enrichment of MART1-reactive TIL. CytoTIL15 cells exhibited ACZ-dependent expansion in response to repeat MART1 stimulation, with TIL reaching maximums of 2, 9, and 18-fold expansion for 0, 1, and 25µM of ACZ, respectively. Chronic antigen exposure revealed an ACZ-driven IL15-dependent enrichment of &gt;80% MART1-reactive TIL, and an increase in effector cytokine production and polyfunctionality (IFNγ, IL2Rα, TNFα, IL2, Perforin, CD107a, Granzyme B). CytoTIL15 cells driven by ACZ demonstrated maintenance of a functional cytotoxic signature, which was enriched in the antigen-reactive cell population. Despite repeated antigen-stimulation, withdrawal of ACZ reduced cytokine production and persistence of the MART1-enriched cytoTIL15 cell population in vitro. In vivo studies further underscored ACZ-dependent tunability of cytoTIL15 cells, as increased ACZ doses enhanced TIL persistence (AUC: 41, 111, and 306%TIL*day for 0, 30, and 200mg/kg ACZ QD), and ACZ withdrawal after 8 days reduced TIL persistence by 1.7-fold. <h3>Conclusions</h3> The expansion and persistence of tumor specific cytoTIL15 cells in the setting of chronic antigen exposure was regulatable by ACZ-dependent mbIL15 expression. This concept supports clinical evaluation of OBX-115 in the relapsed metastatic melanoma setting without concurrent IL-2 administration (NCT05470283).","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"10 4-5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135161755","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}