Regular and Young Investigator Award Abstracts最新文献

{"title":"755 DEKA-1 a dose-finding Phase 1 trial: observing safety and biomarkers using DK2¹⁰(EGFR) for inoperable locally advanced and/or metastatic EGFR+ tumors failing systemic therapy","authors":"Alexander I Spira, Douglas Orr, Aurélien Marabelle, Elizabeth C Moser, Deb Kientop, John Mumm","doi":"10.1136/jitc-2023-sitc2023.0755","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0755","url":null,"abstract":"<h3>Background</h3> Both interleukin-2 (IL-2) and interleukin-10 (IL-10) have been extensively studied for their stimulatory function on T cells and their potential to obtain sustainable tumor control in renal, melanoma, lung, and pancreatic cancers as monotherapy. While approved, IL-2 exhibits significant toxicity in a high percentage of the patient population, limiting its widespread use. The significant efforts undertaken to uncouple IL-2 toxicity from its anti-tumor function have been unsuccessful and early phase clinical safety observed with PEGylated IL-10 was not met in a blinded Phase 3 trial. Deka Biosciences has engineered a novel molecule coupling wild-type IL-2 to a high affinity variant of Epstein Barr Viral (EBV) IL-10 via a scaffold that binds to epidermal growth factor receptors (EGFR). This patented molecule, named DK2¹⁰ (EGFR), is targeted to EGFR expressing cells and demonstrated to be retained at high levels within the tumor microenvironment days after dosing. In addition to overlapping and non-redundant anti-tumor function, IL-10 reduces IL-2 mediated cytokine release syndrome (CRS) risks and inhibits IL-2 mediated T regulatory cell proliferation. <h3>Methods</h3> DK2¹⁰ (EGFR) is being evaluated in an open-label, dose-escalation (Phase 1) study (BOIN design) with five (0.025–0.3 mg/kg) monotherapy dose levels. DK2¹⁰ (EGFR) is home-administered via subcutaneous injection three times a week. The objectives of this study include evaluating the safety, CRS occurrence, pharmacokinetics, pharmacodynamic and predictive biomarkers, presence of anti-drug antibodies, and antitumor activity. <h3>Results</h3> As of June 22, 2023, three patients were enrolled, and are continuing DK2¹⁰ (EGFR) treatment. Subjects improved clinically and no drug related toxicities, nor CRS were observed in any of the patients. One subject with pancreatic cancer achieved stable disease by RECIST 1.1. <h3>Conclusions</h3> DK2¹⁰ (EGFR) couples wild-type IL-2 with a high affinity IL-10 and targets cytokines directly to the tumor microenvironment significantly changing Il-2s therapeutic window. Preliminary human data shows an encouraging safety and efficiency profile. The dose-escalation study is expected to be completed by the end of this year (NCT05704985). <h3>Acknowledgements</h3> The authors would like to thank all patients who participated in this study and their families, as well as all the investigators and site staff who made the study possible. <h3>Trial Registration</h3> Trial Registration www.clinicaltrials.gov; NCT05704985 <h3>Ethics Approval</h3> The study was approved by NEXT Oncology, Salus IRB, approval number NXVIR22.60, on 14-Feb-2023 and by Mary Crowley Medical Research Center Institutional Review Board, approval number 23–08, on 21-Apr-2023. <h3>Consent</h3> Written informed consent was obtained from the patient for publication of this abstract and any accompanying images. A copy of the w","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"64 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":"135162552","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":"708 A phase 1/2 study of rinatabart sesutecan (PRO1184), a novel folate receptor alpha-directed antibody-drug conjugate, in patients with locally advanced and/or metastatic solid tumors","authors":"Justin A Call, Ian Anderson, Ira Winer, Douglas Orr, Oladapo Yeku, Debra L Richardson, Jian Zhang, Elizabeth Lee, Gottfried Konecny, Ning Li, Sandip P Patel, Lin Wu, Jing Wang, Jun Zhang, Ying Cheng, Xiaohua Wu, Naomi Hunder, Lian Lu, Sharon Ma, Eric Song, Erika Hamilton","doi":"10.1136/jitc-2023-sitc2023.0708","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0708","url":null,"abstract":"<h3>Background</h3> Rinatabart sesutecan (Rina-S) is an antibody-drug conjugate (ADC) consisting of a human monoclonal antibody that selectively binds FRα, a novel cleavable hydrophilic linker, and a topoisomerase 1 inhibitor payload, exatecan. The hydrophilic linker confers superior physicochemical properties and pharmacokinetics compared to conventional linkers in preclinical models. Rina-S exerts robust antitumor activity in mouse xenograft models of multiple tumor types with high, moderate, and low FRα expression, consistent with the broad potency and bystander activity of the exatecan payload. Here we present emerging data from the first-in-human trial (NCT05579366). <h3>Methods</h3> PRO1184–001 is an ongoing, phase 1/2, open-label, dose escalation and expansion study. Eligible patients have locally advanced and/or metastatic/unresectable solid tumors, including epithelial ovarian cancer (EOC), endometrial cancer, non-small cell lung cancer (NSCLC), breast cancer, or mesothelioma. Patients must have measurable disease per the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, or mRECIST 1.1 for pleural mesothelioma. FRα tumor expression levels were retrospectively tested using the Ventana immunohistochemistry FOLR1 assay. Primary objectives are to identify the maximum tolerated dose, recommended phase 2 dose, and evaluate safety and tolerability. <h3>Results</h3> As of 09 June 2023, 10 patients have been treated with Rina-S at 60 (n=3) and 120 (n=7) mg/m². Tumor types included platinum-resistant/refractory EOC (n=5), endometrial cancer (n=2), NSCLC (n=2), and mesothelioma (n=1). Patients received a median of 4 (range, 1 to 9) prior treatments. Eight patients completed the DLT period and had post-baseline tumor assessments per RECIST. The other 2 patients, who had FRα-negative tumors, discontinued due to early clinical progression. Patients have received between 1 and 8 cycles and 5 remain on treatment. The most common treatment-related adverse events (AEs) were nausea (n=5), decreased white blood cell counts (n=3), and fatigue, decreased lymphocyte counts, and decreased neutrophil counts (n=2 each); most events were Grade 1 or 2. Treatment-related ≥ Grade 3 hematologic AEs were reported for 2 patients treated at 120 mg/m². No ocular toxicity or interstitial lung disease was observed. No DLTs were observed. Antitumor activity was observed at both dose levels and in patients with high, medium, and low FRα expression, including an ongoing confirmed partial response in a patient with endometrial cancer and decreased tumor measurements in additional patients. <h3>Conclusions</h3> Emerging data suggest a promising safety profile for Rina-S, with most AEs being mild or moderate and consistent with findings in preclinical studies. Antitumor activity has been observed at well tolerated dose levels. Dose escalation continues. <h3>Trial Registration</h3> Clinicaltrials.gov NCT05579366 <h3>Ethics Approval</h3> The study obt","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"63 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":"135162554","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":"947 The activation states of tumor-resident type 2 dendritic cells impact the strength of ovarian cancer immune responses","authors":"Fiona Chatterjee, Vincent Butty, Emi A Lutz, K Dane Wittrup, Stefani Spranger","doi":"10.1136/jitc-2023-sitc2023.0947","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0947","url":null,"abstract":"<h3>Background</h3> Ovarian cancer is the fifth leading cause of cancer-related death in women in the United States.¹ To date, checkpoint blockade therapy (CBT) has failed to be effective in ovarian cancer.² CBT efficacy typically requires a strong pre-existing tumor-specific T cell response.^{3 4} However, analysis of patient data indicates that tumor-infiltrating T cells in ovarian cancer are often poorly activated.⁵ Understanding the mechanisms governing this poor T cell activation could lead to novel ovarian cancer therapeutics. <h3>Methods</h3> We utilized a transplantable, syngeneic, murine ovarian cancer cell line driven by Ccne1^OE p53^-/-R172H Ak2^OE and Kras^G12V (CPAK).⁶ CPAK tumor cells were implanted intraperitoneally to model metastatic ovarian cancer or subcutaneously to model productive systemic immunity. CPAK cells were engineered to express the model CD8⁺ T cell antigen SIY to enable studies of tumor-specific T cells. CBT consisted of αCTLA-4 and αPD-L1 therapy. Immune cells were profiled using flow cytometry and single-cell RNA sequencing (scRNA-seq). <h3>Results</h3> Intraperitoneal (IP) CPAK-SIY tumors were unresponsive to CBT. However, mice bearing subcutaneous (SQ) CPAK-SIY tumors treated with CBT displayed delayed tumor growth compared to control animals. Flow cytometric analysis of tumor-infiltrating CD8⁺ T cells illustrated that while tumor-reactive T cells were activated in IP and SQ tumors, tumor-reactive T cells in IP tumors failed to upregulate high levels of effector molecules such as granzyme B. Unbiased analysis of dendritic cells (DCs) within IP tumors using scRNA-seq revealed a population of DCs that expressed CD103 and CD11b and a type 2 conventional DC (cDC2) gene signature. Gene signature analysis indicated these CD103⁺ CD11b⁺ double-positive DCs were a suppressive state of cDC2s induced by TGFb that reside in gut tissue and induce Tregs.⁷ Analysis of tumor-infiltrating DCs in IP tumors revealed that the proportion of double-positive DCs increased during tumor growth while the proportion of cDC2s decreased. We hypothesized that the polarization of cDC2s away from these suppressive double-positive DCs may improve ovarian cancer immunity. Previous work from our group demonstrated that cDC2s acquire an activation state characterized by an interferon-stimulated gene signature (ISG⁺ DCs) upon exposure to interferon-beta (IFNβ) and that ISG⁺ DCs are potent activators of CD8⁺ T cells.⁸ In our ovarian cancer model, addition of IFNβ to IP tumors enhanced tumor-specific T cell responses. <h3>Conclusions</h3> Metastatic ovarian tumors are refractory to CBT and are infiltrated by poorly activated CD8⁺ T cells. Our results suggest that the poor T cell activation is a consequence of the cDC2 activation state within the tumor","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"50 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":"135162561","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":"1227 Oral inulin gel formulation modulates the gut microbiome and improves the safety and efficacy of immune checkpoint blockers","authors":"Jin Xu, Kai Han, Xuehui Huang, James J Moon","doi":"10.1136/jitc-2023-sitc2023.1227","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.1227","url":null,"abstract":"<h3>Background</h3> The dysregulated gut microbiota found in cancer patients is emerging as the new therapeutic target. Here, we have engineered inulin – a widely consumed dietary fiber – into an oral gel formulation to modulate the gut microbiota and the host immune responses. We show that inulin gel improves the safety and anti-tumor efficacy of immune checkpoint blockers (ICBs) in various murine tumor models. <h3>Methods</h3> We have optimized the scale-up production of inulin gel. In tumor-bearing mice, inulin gel was orally administered starting day 7 after tumor inoculation, while anti-PD-1 was intraperitoneally injected from day 10. The gut microbiota profile in fecal samples was examined by 16s rRNA gene sequencing, and the metabolites in feces and serum were tested by ion- or liquid-chromatography. Tumor-infiltrating lymphocytes were measured via flow cytometry. In addition, inulin gel was tested on the mouse ICBs-associated colitis model, where 3% dextran sulphate sodium (DSS) was supplied in the drinking water. <h3>Results</h3> After oral gavage in mice, inulin gel formulation was retained longer in the colon, thus increasing the cumulative inulin exposure and fermentation in the colon. Consequently, inulin gel increased the frequencies of <i>Akkermensia</i> as well as other commensal microbes known to modulate the systemic and colonic immune responses. Oral administration of inulin gel markedly augmented the antitumor efficacy of anti-PD-1 and anti-CTLA-4 ICBs in multiple tumor models, including CT26 colon carcinoma, B16F10 melanoma, and DSS-accelerated colon tumour model in <i>CDX2-cre NLS-APC</i>fl/fl mice. Notably, colitis is one of the most frequently observed immune-related adverse events (irAEs) associated with ICB therapy in the clinic. Our results showed that oral administration of inulin gel ameliorated DSS-induced, ICBs-exacerbated colitis, suggesting that inulin gel can also improve the safety profiles of ICB therapy. Metabolomics analysis revealed that inulin gel plus anti-PD-1 increased the concentrations of short-chain-fatty-acids, which promoted the differentiation of stem-like Tcf1⁺PD-1⁺CD8⁺ T cells, conferring long-lasting protection against tumor re-growth. Meanwhile, inulin gel plus anti-PD-1 decreased the concentrations of ATP and L-Phenylalanine that could exacerbate colitis. Toward the goal of initiating a human clinical study, we have optimized the scale-up manufacturing of inulin gel. <h3>Conclusions</h3> Orally administered inulin gel formulation normalizes the dysregulated gut microbiome, improves the host immune responses, and decreases the ICB-associated colitis. Based on this work, we are initiating a Phase I study to examine the impact of inulin gel consumption in healthy volunteers. <h3>Acknowledgements</h3> This work was supported by NIH (R01AI127070, R01CA210273, U01CA210152, R01DK108901, R01DE026728, R01DE030691, R01DE031951) and the University of Michigan Rogel Cancer","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"65 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":"135162804","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":"330 Combination therapy with stem cell derived natural killer cells and monoclonal antibodies leads to potent ADCC through engagement of endogenouse CD16","authors":"Anna-Maria Georgoudaki, Nina Lamers-Kok, Amanda van Vliet, Didem Özkazanc, Denise Vodegel, Daniëlle Steenmans, Monica Raimo, Adil Duru, Jan Spanholtz","doi":"10.1136/jitc-2023-sitc2023.0330","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0330","url":null,"abstract":"<h3>Background</h3> Glycostem’s ex vivo expansion and differentiation method in a fully closed automated manufacturing platform (uNiK™), generates GTA002 (oNKord®), an ‘off-the-shelf’ allogeneic cryopreserved NK cell product derived from umbilical cord blood CD34+ hematopoietic stem cell progenitor cells, which is currently being tested in a Phase I/II clinical trial in AML, WiNK (NCT04632316). Safety and tolerability of a non-cryopreserved predecessor was demonstrated in an earlier Phase I trial in AML (Dolstra et al. 2017). One of the important outcomes of this study was the notable increase in the CD16 expression of infused NK cells. Thus, we next exploited the potential of further enhancing and focusing cryopreserved NK cell anti-tumor responses in an antigen (Ag)-specific manner via antibody-dependent cellular cytotoxicity (ADCC) in pre-clinical models of hematological and solid malignancies. <h3>Methods</h3> Similar to its predecessor non-cryopreserved NK cells, GTA002 significantly upregulated CD16 expression in vivo in immunodeficient NCG mice. This spurred the optimization of the culture process to upregulate CD16 expression in order to study the ADCC potential of GTA002 in vitro. ADCC was assessed against CD19⁺ and HER2⁺ targets at low effector-to-target (E:T) ratios by end-point flow cytometry assays as well as impedance- and live imaging- (2D &amp; 3D) based real time analysis. Next, we engineered CD16-NK cells by introduction of a lentiviral transduction step to the uNiK™ platform, to evaluate the effect of CD19-targeted ADCC of NK cells expressing engineered or endogenous CD16. Furthermore, expression of important activating and inhibitory receptors and intracellular levels of TNF, IFNγ, perforin and granzyme B were measured by flow cytometry to investigate their role in efficient cytotoxicity of GTA002 cells. We detected simultaneous tumor targeting by GTA002, both via preserved innate NK cell responses as well as Ag-specific targeting via ADCC at low E:T ratios. <h3>Results</h3> Moreover, GTA002 cells were tested for their ability to mediate killing of an ovarian cancer cell line in the presence of an Fc-active monoclonal antibody (mAb) targeting a tumor associated antigen expressed by SKOV-3 cells. Impedance-based cytotoxicity assays revealed that GTA002 exerted potent ADCC upon CD16 engagement. Addition of cytokine support further enhanced both baseline cytotoxicity as well as ADCC, leading to complete eradication of the SKOV-3 tumor cells. <h3>Conclusions</h3> Overall, the enhancement of the inherent potency of GTA002 by harnessing ADCC through combination therapy with mAbs achieved efficient Ag-specific responses demonstrating the great potential of multimodal targeting against a variety of challenging cancers using a highly safe ‘off-the-shelf’ NK cell-based cellular therapeutic.","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"54 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":"135162991","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":"403 Tumor-infiltrating lymphocytes (TIL) with inducible and membrane-bound IL-12 exhibit superior antitumor activity<i>in vitro</i>","authors":"Yongliang Zhang, Nathan Gilbert, Patrick Innamarato, Judy Fang, Hequn Yin","doi":"10.1136/jitc-2023-sitc2023.0403","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0403","url":null,"abstract":"<h3>Background</h3> TIL cell therapy has shown clinical benefit for patients with solid tumors.^{1 2} However, an immunosuppressive tumor microenvironment (TME) may abrogate the full potential of TIL cell therapy.³ The proinflammatory cytokine IL-12, known for its capability to increase IFN-γ production and promote type 1 immune responses, reshapes the TME and has a potential to augment antitumor activity. Here, we report genetic engineering of TIL with an inducible and membrane-bound IL-12, incorporated into a 22-day manufacturing process, which showed superior cytotoxic function <i>in vitro</i>. <h3>Methods</h3> Tumor tissue from several solid tumor types, including non-small cell lung, breast, head and neck, and ovarian cancers, was fragmented and cultured, followed by transduction with lentivirus containing a gene encoding membrane-bound IL-12 via an NFAT-promoter (TeIL-12), and a rapid expansion protocol (REP). Expression, biological function, and shedding of IL-12 molecule were assessed <i>in vitro</i>. Immune phenotype and <i>in vitro</i> cytotoxic activity of TeIL-12 gene-engineered TIL were examined in various assays. <h3>Results</h3> Lentiviral gene transfer resulted in TIL expressing IL-12 on their surface via a membrane anchor. This modification potentiated IL-12 receptor downstream signaling activation in a contact-dependent manner in assays using HEK-IL-12-Blue reporter cells. TeIL-12-TIL exhibited increased IFN-γ production and superior cytotoxicity in a KILR assay. An xCELLigence-based cytotoxicity assay further confirmed increased killing with TIL that were unstimulated or stimulated. Moreover, phenotype profiling revealed TeIL-12-TIL were less differentiated, with reduced expression of immune-inhibitory receptors and increased production of cytotoxic molecules associated with antitumor activity. IL-12 shedding in the co-culture supernatant was minimal. <h3>Conclusions</h3> The enhanced <i>in vitro</i> killing activity, combined with a less-differentiated phenotype of TIL with inducible and membrane-bound IL-12 suggests a potential for increased clinical efficacy. Further, minimal IL-12 shedding supports reduced potential for IL-12-associated toxicity.⁴ Together, these data support investigation of TeIL-12 <i>in vivo</i> and subsequent clinical development. <h3>Acknowledgements</h3> Editorial support was provided by Amanda Kelly (Iovance Biotherapeutics). <h3>References</h3> Chesney J, Lewis KD, Kluger H, <i>et al</i>. Efficacy and safety of lifileucel, a one-time autologous tumor-infiltrating lymphocyte (TIL) cell therapy, in patients with advanced melanoma after progression on immune checkpoint inhibitors and targeted therapies: pooled analysis of consecutive cohorts of the C- 144–01 study. <i>Journal for ImmunoTherapy of Cancer</i> 2022;<b>10</b>:e005755. Schoenfeld AJ, Lee S, Paz-Ares L, <i>et al.</i> First phase 2 results of autologous tumor-infiltrating lymphocyte (TIL; LN-145) monotherapy in p","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"69 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":"135163179","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":"222 The chick embryo chorioallantoic membrane (CAM) as a platform for assessing the in vivo efficacy of chimeric antigen receptor (CAR) T cell therapy in solid tumors","authors":"Allison Nipper, Emilie AK Warren, Gabrielle Wells, Caroline Porter, Mariana Villanueva, Hsuan-Chen Liu, Hugo Villanueva, Masataka Suzuki, Andrew Sikora","doi":"10.1136/jitc-2023-sitc2023.0222","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0222","url":null,"abstract":"<h3>Background</h3> While chimeric antigen receptor T cell (CAR T) treatment has been efficacious in blood cancers, mirroring this success in solid tumors, like head and neck squamous cell carcinoma (HNSCC) has proven difficult due to the challenge of identifying and validating suitable target antigens. To rapidly model CAR-T treatment against HNSCC antigens, we have developed a robust, scalable model using fertilized chicken eggs to facilitate CAR-T screening against vascularized solid tumors. The fertilized chicken egg inner shell membrane, the chorioallantoic membrane (CAM), is a highly vascularized membrane which facilitates nutrient delivery and oxygen exchange for growth of the developing chick. The nutrient transfer capabilities of the CAM can be exploited to drive the formation of vascularized solid tumors which can be targeted by CAR T within one week of engraftment. In contrast to murine systems which can be costly, labor intensive, or use murine cells, this system quickly models the development of human cancers expressing human epitopes treated with human cell therapies. <h3>Methods</h3> HER2+ (FaDu and SCC-47) and HER2- (MDA-MB-468) cell lines with luciferase reporters were engrafted onto the CAM. Tumor growth was monitored by IVIS imaging of luciferase activity of viable tumor cells. Engrafted cells grew for three days during which tumors establish and incorporate into the CAM. Established tumors were treated with second generation HER2-directed CAR T with a CD28 costimulatory endodomain or an expanded T cell control which was not transduced with CARs. Viability of tumor cells was monitored through quantification of luciferase activity from engrafted cells before and following four days of CAR-T treatment. Histology was used to visualize tumor structure on the CAM and CAR-T infiltration of tumor tissue. Staining was scored by percent positive area and intensity using QuPath software. <h3>Results</h3> Luciferase activity of viable tumor cells was significantly reduced in CAR-T treated FaDu tumors (p<0.0001). Following tumor harvest, we observed a significant reduction in Ki67 staining for CAR-T treated tumors relative to T cell treatment alone for both SCC-47 and FaDu tumors (p=0.0121 and p=0.0176 respectively). We also observed CAR-T persistence in tissue and infiltration of tumors. <h3>Conclusions</h3> The CAM system supports the growth of solid tumors which can be targeted by immune cell infiltrates. These data support continued development of the chick CAM model as a candidate in vivo system for rapid, scalable screening of CAR T efficacy against human solid tumors.","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"69 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":"135163181","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":"297 Improvement of CAR T-cell performance by simultaneous downregulation of multiple co-inhibitory receptors","authors":"Matteo Rossi, Fanny Huberty, Thuy Nguyen, Jerome Marijsse, Celine Jacques-Hespel, Eytan Breman","doi":"10.1136/jitc-2023-sitc2023.0297","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0297","url":null,"abstract":"<h3>Background</h3> Co-inhibitory receptors, such as PD-1 and LAG-3, have a crucial role in regulating T-cell activity, as their expression on the cell surface upon chronic T-cell activation is associated with T-cell exhaustion. Immunotherapies directed against co-inhibitory receptors exhibited unprecedented efficacy in several cancer indications. However, many patients do not respond to these therapies and some tumor types remain largely refractory. A key determinant of CAR T-cell failure against solid tumors is T-cell exhaustion induced by checkpoint inhibitors on cancer cells. The coordinated targeting of different co-inhibitory receptors may help overcome these hurdles. Here we show that the simultaneous downregulation of co-inhibitory receptors PD-1, LAG-3, TIM-3 and TIGIT endows CAR T-cells with superior efficacy. <h3>Methods</h3> A microRNA (miRNA)-based short hairpin RNA (shRNA) platform was developed, to allow for the tunable modulation of multiple target genes simultaneously. The platform was equipped with shRNA-derived guide sequences (shGuides) targeting PD-1, LAG-3, TIM-3 and TIGIT, and combined with an anti-CD19 CAR. The shRNA platform-equipped CAR T-cells were challenged with target cancer cells expressing the co-inhibitory receptors’ ligands. The impact of the simultaneous downregulation of the four co-inhibitory receptors was assessed <i>in vitro</i> by monitoring T-cell activation (via surface activation markers and cytokine secretion), killing activity, and persistence (via repeated challenges with the target cells). <h3>Results</h3> The miRNA-derived shRNA platform targeting PD-1, LAG-3, TIM-3 and TIGIT led to a significant downregulation of the four co-inhibitory receptors in the CAR T-cells. Upon activation by the target cancer cells, the simultaneous knock-down of the four genes enhanced cytokine secretion compared to CAR T-cells not engineered with the shRNA platform. Moreover, the CAR T-cells carrying the quadruple knock-down showed superior killing ability, increased persistence and prolonged activity when repeatedly challenged in sequential cycles with the target cancer cells. <h3>Conclusions</h3> These data validate our technology for the effective introduction of multiple functionally relevant edits in CAR T-cells. Co-inhibitory receptors concomitantly contribute at regulating T-cell responses, making it difficult to inhibit or knock-out multiple receptors together. With our approach we proved the feasibility of the simultaneous knock-down of PD-1, LAG-3, TIM-3 and TIGIT. Moreover, we show increased performance of the engineered CAR T-cells, suggesting that the simultaneous downregulation of the four co-inhibitory receptors may improve the antitumor activity of adoptive cell therapy. This strategy may empower the CAR T-cells to successfully target tumors reliant on high expression of immune checkpoint molecules and therefore often refractory to immunotherapy, such as solid tumors.","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"56 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":"135163191","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":"355 Directing a high avidity KRAS G12D-specific TCR engineered with a CD8αβ co-receptor and chimeric cytokine receptor using non-viral knock-in enhances anti-tumor responses","authors":"Allison P Drain, Nicholas Rouillard, Nathaniel Swanson, Santosh Narayan, Tyler Warner, Nicole Danek, Ken Gareau, Cheryl Black, James Parsons, Anthony Thomas, Jinsheng Liang, Luhua Shen, Tanya Tetrault, Vince Nguyen, Iqraa Priyata, Sarah Vidyasagar, Joshua Francis, Xingyue He, Patrick J Browne, Rebecca C Lamothe, Meghan D Storlie, Gregory J Cost, Thomas M Schmitt, Philip D Greenberg, Smita S Chandran, Christopher A Klebanoff, Ankit Gupta, Damien Hallet, Gary Shapiro, Kim Nguyen, Loic Vincent","doi":"10.1136/jitc-2023-sitc2023.0355","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0355","url":null,"abstract":"<h3>Background</h3> Adoptive T cell therapy has demonstrated clinical activity in a subset of patients with solid tumors; however, consistent responses will require further optimization. T cell receptor (TCR)-engineered T cells recognize peptides derived from intracellular and surface proteins presented in the context of MHC class I. Immunologic targeting of recurrently mutated oncogenic drivers, such as KRAS, overcomes many of the major obstacles of this modality because the resulting epitope is: 1) tumor-specific, 2) essential for cancer cell fitness, and 3) derived from a stably expressed non-self protein. AFNT-212 is a next-generation engineered T cell therapy that uses non-viral targeted knock-in (KI) at the TCRα constant (<i>TRAC</i>) locus to express a multi-cistronic cassette that includes 1) a high-affinity TCR specific for KRAS_G12D mutation, 2) a CD8αβ coreceptor, and 3) a chimeric cytokine receptor. <h3>Methods</h3> Human CD4⁺ and CD8⁺ T cells were genetically engineered by a novel CRISPR-Cas nuclease and gRNAs targeting <i>TRAC</i> and the TCRβ constant (<i>TRBC</i>) genes allowing for knock-out of the endogenous TCR loci and simultaneous integration of the non-viral plasmid-based transgene cassette. Engineered T cells were assessed for specificity and potency, including activation, proliferation, and cytotoxicity, against KRAS G12D peptide presented by HLA-A*11:01 and a panel of KRAS G12D-expressing tumor cell lines. <i>In vitro</i> safety studies were performed along with <i>in vivo</i> efficacy studies in multiple human xenograft models. <h3>Results</h3> Engineered primary T cells showed specific recognition of KRAS G12D peptide, demonstrated cytotoxicity against endogenously expressing HLA-A*11:01⁺/KRAS G12D⁺ cell lines in tumor cell re-challenge assays <i>in vitro</i>, and mediated robust anti-tumor activity <i>in vivo</i>. Inclusion of the chimeric cytokine receptor allowed for a more potent anti-tumor response stemming from improved T cell expansion and resistance to exhaustion. No off-target liabilities were identified upon co-incubation of AFNT-212 with all possible peptides in the human proteome matching the xScan-defined epitope recognition motif for the TCR, demonstrating specificity. Gene editing safety evaluation did not reveal any off-target activity for the CRISPR-Cas nucleases and engineered T cells did not show cytokine-independent proliferation, collectively supporting a favorable pre-clinical safety profile for AFNT-212. <h3>Conclusions</h3> We report a novel TCR gene therapy approach targeting mutant KRAS G12D-expressing tumors with a coordinated CD4/CD8 T cell response that has a promising efficacy and safety profile. Our work supports the planned clinical development of AFNT-212 as a novel non-viral KI TCR-engineered T cell therapy for KRAS-mutant solid tumors.","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"56 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":"135163192","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":"742 Phase 1/2 study of the bispecific 4–1BB and PD-L1 antibody INBRX-105 alone and in combination with pembrolizumab in select solid tumors","authors":"Jong Chul Park, David Berz, Manish Sharma, Erminia Massarelli, Ralph J Hauke, Frank Yung-Chin Tsai, David Hong, Neal Akhave, Justin A Call, Jennifer Carlisle, Rachel E Sanborn, Naomi B Haas, John Hamm, D Ross Camidge, Alexander I Spira, Vasily Andrianov, Brianne O’Neill, Heather Kinkead, Anthony W Tolcher","doi":"10.1136/jitc-2023-sitc2023.0742","DOIUrl":"https://doi.org/10.1136/jitc-2023-sitc2023.0742","url":null,"abstract":"<h3>Background</h3> 4–1BB is a costimulatory receptor upregulated on tumor-infiltrating lymphocytes. 4–1BB signaling promotes T-cell proliferation and activation and decreases T-cell exhaustion. 4–1BB agonists have shown promising antitumor activity but have been limited by hepatotoxicity resulting from systemic 4–1BB activation. INBRX-105 is a 4–1BB×PD-L1 bispecific antibody designed to localize 4–1BB costimulatory signaling to PD-L1-rich environments. INBRX-105 consists of 2 agonistic 4–1BB single-domain antibodies (sdAbs) and 2 PD-L1 sdAbs, which allow anchoring to PD-L1. Cross-linking of PD-L1 to 4–1BB by INBRX-105 leads to conditional 4–1BB activation at sites of high PD-L1 expression, potentially limiting toxicities associated with prior 4–1BB agonists. In mouse tumor models, an INBRX-105 surrogate (INBRX-105-a) exhibited antitumor efficacy and increased T-cell frequency in the tumor microenvironment.¹ Robust proliferation of CD8⁺ T effector memory cells was observed intratumorally and in peripheral blood. INBRX-105-a plus a PD-1 antagonist resulted in greater inhibition of tumor growth. We describe a phase 1/2 study (NCT03809624) of INBRX-105 alone and in combination with pembrolizumab in patients with solid tumors. <h3>Methods</h3> This open-label, 4-part study of INBRX-105±pembrolizumab in locally advanced unresectable/metastatic solid tumors (N≈300) is enrolling in the US (figure 1). Dose escalation (part 1, INBRX-105 single agent; part 3, combination) was completed. INBRX-105 is being assessed in dose-expansion cohorts (part 2, INBRX-105 single agent; part 4, combination). Patients naive to 4–1BB agonists with disease that progressed despite standard therapy or who have no alternative treatment options (except checkpoint inhibitor [CPI]-naive cohorts) were included. Part 2a (recommended phase 2 dose [RP2D] expansion) consists of 4 cohorts: non-small cell lung cancer (NSCLC; PD-L1+), melanoma/solid tumors, head and neck squamous cell carcinoma (HNSCC), and other solid tumors (PD-L1+). Part 2b includes PD-L1-high HNSCC (including nasopharyngeal carcinoma). All part 2 cohorts, except melanoma (noncutaneous)/solid tumors, were CPI relapsed/refractory. PD-L1+ NSCLC (part 2a) and PD-L1-high HNSCC (part 2b) cohorts were opened based on encouraging early single-agent activity. Cohorts are enrolling and complete data readouts are forthcoming. Part 4 consists of CPI-relapsed/refractory cohorts (PD-L1+ NSCLC, cutaneous melanoma, PD-L1+ HNSCC, microsatellite instability-/tumor mutation burden-high or mismatch repair-deficient solid tumors) and CPI-naive cohorts (PDL1+ NSCLC and HNSCC). PD-L1 immunohistochemistry scores are required in parts 2 and 4, with threshold scores defined per protocol. Primary objectives are safety and determination of the maximum tolerated dose and/or RP2D of INBRX-105 as monotherapy and with pembrolizumab. Secondary objectives include pharmacokinetics, immunogenicity, and preliminary antitumor activi","PeriodicalId":500964,"journal":{"name":"Regular and Young Investigator Award Abstracts","volume":"38 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":"135163211","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}