scholarly journals IMMU-08. MICROENVIRONMENT MODULATION BY TIM-3 BLOCKADE IMPROVES THE OUTCOME OF PRECLINICAL DIPG MODELS

2021 ◽  
Vol 23 (Supplement_1) ◽  
pp. i28-i28
Author(s):  
Iker Ausejo-Mauleon ◽  
Sara Labiano ◽  
Virginia Laspidea ◽  
Marc Garcia-Moure ◽  
Daniel de la Nava ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
Nk Cells ◽  
Immune Cell ◽  
Cell Types ◽  
Pediatric Brain Tumors ◽  
Immune Memory ◽  
Cd8 Cells ◽  
Functional Studies

Abstract Diffuse Midline Gliomas (DMGs), encompassing Diffuse Intrinsic Pontine Gliomas (DIPGs), are the most aggressive pediatric brain tumors. Their meagre survival has not changed despite the combination of radiotherapy with targeted therapies emphasizing the urgent need for effective treatments. Recent research suggested that the DIPG tumor microenvironment is neither highly immunosuppressive nor inflammatory. These analyses showed the lack of infiltrating lymphocytes and the abundance of CD11b+ cells. TIM-3 (HAVCR2) is a member of the T-cell immunoglobulin and mucin domain protein family which is expressed on multiple immune cell types including T cells, Tregs, NK cells, monocytes, dendritic cells and microglia, where it potently regulates not only adaptive immunity but also innate immunity. Therefore, the central hypothesis of this study is that TIM-3 inhibitors could stimulate a cytotoxic immune effect and challenge several components in the tumor microenvironment including microglia, thereby providing a potential effective treatment for DMGs. In silico assessment of TIM-3 expression in a DIPG datasets showed a robust expression of this gene. Moreover, single-cell sequencing analyses of DIPG biopsies uncover its expression on tumor cells, especially in the OPCs compartment. In vivo efficacy studies showed that treatment with anti-TIM-3 antibody significantly increase the overall survival in two DIPG immunocompetent orthotopic animal models (doubling the median), lead to long-term survivors (50%) and showed immune memory. Analyses of CD45+ populations in the tumor microenvironment showed a significant increase in B, NK and CD8+ cells corresponding with a T-cell activate phenotype in treated-mice. The potential therapeutic involvement of NK cells was certified using nude mice and functional studies. Involvement of microglia in currently being analysed. In summary, these data underscore TIM-3 as a potential target DIPGs and uncover the potential involvement of NKs and other immune mechanisms in the efficacy of anti-TIM-3 therapy.

scholarly journals 283 TIM-3 blockade modulates the tumor microenvironment improving the outcome of preclinical pediatric diffuse midline glioma models

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A307-A307
Author(s):  
Iker Ausejo-Mauleon ◽  
Sara Labiano ◽  
Virginia Laspidea ◽  
Marc Garcia-Moure ◽  
Daniel de la Nava ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
Nk Cells ◽  
Immune Cell ◽  
Animal Experiments ◽  
Cell Types ◽  
Immune Memory ◽  
List Type ◽  
Treg Population

BackgroundDiffuse Midline Gliomas (DMGs), encompassing Diffuse Intrinsic Pontine Gliomas (DIPGs), are the most aggressive pediatric brain tumors. Their meager survival has not changed despite the combination of radiotherapy with targeted therapies emphasizing the urgent need for effective treatments. Recent research suggested that the DIPG tumor microenvironment is neither highly immunosuppressive nor inflammatory.1 These analyses showed the lack of infiltrating lymphocytes and the abundance of CD11b+ cells. TIM-3 is a member of the T-cell immunoglobulin and mucin domain protein family expressed on multiple immune cell types, including T cells, Treg, NK cells, monocytes, dendritic cells, and microglia, where it potently regulates not only adaptive immunity but also innate immunity.2–3 Therefore, TIM-3 inhibitors could challenge several components in the tumor microenvironment, thereby providing potentially effective treatment for DMGs.MethodsNP53 and XFM murine DIPG cell lines were used for animal experiments in immunocompetent orthotopic models. The tumors were processed by mechanical and enzymatic digestion and immune populations were analyzed by a flow cytometry panel. Antibodies against NK cells (NK1.1), CD4 (GK1.5), CD8 (CD8β) were used for animal depletion experiments alone or in combination.ResultsIn silico assessment of TIM-3 expression in DIPG datasets showed a robust expression of this gene. Moreover, single-cell sequencing analyses of DIPG biopsies uncover its expression in the myeloid compartment (especially in microglia). In vivo efficacy studies showed that treatment with anti-TIM-3 antibody significantly increased the overall survival in two DIPG immunocompetent orthotopic animal models (doubling the median), lead to long-term survivors free of disease (50%) and showed immune memory. Analyses of CD45+ populations in the tumor microenvironment showed a significant increase in microglia, granulocytes, NK and CD8+ cells corresponding with a NK and T-cell activate phenotypes in treated-mice. In addition, we have a substantial decrease in the Treg population, which causes an increase in the CD8/Treg ratio. CD4 and CD8 T-cell depletion led to a significant but not total loss of treatment efficacy. NK cells depletion also reduced the effectiveness of this therapy, albeit to a lesser extent than CD4-CD8 depletion. We are currently investigating the role of microglia in the outcome of the treatment.ConclusionsOur data uncovered TIM-3 as a potential target for the treatment of DIPG tumors. Inhibition of this molecule led to a potent antitumor effect mediated by a profound tumor microenvironment remodelling.ReferencesLieberman NAP, DeGolier K, Kovar HM, et al. Characterization of the immune microenvironment of diffuse intrinsic pontine glioma: implications for development of immunotherapy. Neuro Oncol 2019;21(1):83–94. doi:10.1093/neuonc/noy145.Acharya N, Sabatos-Peyton C, Anderson AC. Tim-3 finds its place in the cancer immunotherapy landscape. J Immunother Cancer 2020;8(1):e000911. doi:10.1136/jitc-2020-000911.Wolf Y, Anderson AC, Kuchroo VK. TIM3 comes of age as an inhibitory receptor. Nat Rev Immunol 2020;20(3):173–185. doi:10.1038/s41577-019-0224-6

scholarly journals Single cell transcriptomics reveals the effect of PD-L1/TGF-β blockade on the tumor microenvironment

2020 ◽  
Author(s):  
Yoong Wearn Lim ◽  
Garry L. Coles ◽  
Savreet K. Sandhu ◽  
David S. Johnson ◽  
Adam S. Adler ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
Single Cell ◽  
Immune Cell ◽  
Single Cells ◽  
Cell Infiltration ◽  
Cytotoxic Lymphocytes ◽  
T Cell Infiltration ◽  
Anti Tumor Activity

AbstractBackgroundThe anti-tumor activity of anti-PD-1/PD-L1 therapies correlates with T cell infiltration in tumors. Thus, a major goal in oncology is to find strategies that enhance T cell infiltration and efficacy of anti-PD-1/PD-L1 therapy. TGF-β has been shown to contribute to T cell exclusion and anti-TGF-β improves anti-PD-L1 efficacy in vivo. However, TGF-β inhibition has frequently been shown to induce toxicity in the clinic, and the clinical efficacy of combination PD-L1 and TGF-β blockade has not yet been proven. To identify strategies to overcome resistance to PD-L1 blockade, the transcriptional programs associated with PD-L1 and/or TGF-β blockade in the tumor microenvironment should be further elucidated.ResultsFor the first time, we used single-cell RNA sequencing to characterize the transcriptomic effects of PD-L1 and/or TGF-β blockade on nearly 30,000 single cells in the tumor and surrounding microenvironment. Combination treatment led to upregulation of immune response genes, including multiple chemokine genes such as CCL5, in CD45+ cells, and down-regulation of extracellular matrix genes in CD45-cells. Analysis of publicly available tumor transcriptome profiles showed that the chemokine CCL5 was strongly associated with immune cell infiltration in various human cancers. Further investigation with in vivo models showed that intratumorally administered CCL5 enhanced cytotoxic lymphocytes and the anti-tumor activity of anti-PD-L1.ConclusionsTaken together, our data could be leveraged translationally to improve anti-PD-L1 plus anti-TGF-β combination therapy, for example through companion biomarkers, and/or to identify novel targets that could be modulated to overcome resistance.

scholarly journals Harnessing the cDC1-NK Cross-Talk in the Tumor Microenvironment to Battle Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Johanna Bödder ◽  
Tasmin Zahan ◽  
Rianne van Slooten ◽  
Gerty Schreibelt ◽  
I. Jolanda M. de Vries ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
Nk Cells ◽  
Tumor Cells ◽  
Cross Talk ◽  
T Cell Responses ◽  
Cell Types ◽  
Suppressive Effect ◽  
Cell Responses

Immunotherapeutic approaches have revolutionized the treatment of several diseases such as cancer. The main goal of immunotherapy for cancer is to modulate the anti-tumor immune responses by favoring the recognition and destruction of tumor cells. Recently, a better understanding of the suppressive effect of the tumor microenvironment (TME) on immune cells, indicates that restoring the suppressive effect of the TME is crucial for an efficient immunotherapy. Natural killer (NK) cells and dendritic cells (DCs) are cell types that are currently administered to cancer patients. NK cells are used because of their ability to kill tumor cells directly via cytotoxic granzymes. DCs are employed to enhance anti-tumor T cell responses based on their ability to present antigens and induce tumor-antigen specific CD8+ T cell responses. In preclinical models, a particular DC subset, conventional type 1 DCs (cDC1s) is shown to be specialized in cross-presenting extracellular antigens to CD8+ T cells. This feature makes them a promising DC subset for cancer treatment. Within the TME, cDC1s show a bidirectional cross-talk with NK cells, resulting in a higher cDC1 recruitment, differentiation, and maturation as well as activation and stimulation of NK cells. Consequently, the presence of cDC1s and NK cells within the TME might be of utmost importance for the success of immunotherapy. In this review, we discuss the function of cDC1s and NK cells, their bidirectional cross-talk and potential strategies that could improve cancer immunotherapy.

scholarly journals Single-cell transcriptomics reveals the effect of PD-L1/TGF-β blockade on the tumor microenvironment

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Yoong Wearn Lim ◽  
Garry L. Coles ◽  
Savreet K. Sandhu ◽  
David S. Johnson ◽  
Adam S. Adler ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
Single Cell ◽  
Immune Cell ◽  
Single Cells ◽  
Cell Infiltration ◽  
In Vivo Models ◽  
T Cell Infiltration ◽  
Anti Tumor Activity

Abstract Background The anti-tumor activity of anti-PD-1/PD-L1 therapies correlates with T cell infiltration in tumors. Thus, a major goal in oncology is to find strategies that enhance T cell infiltration and efficacy of anti-PD-1/PD-L1 therapy. TGF-β has been shown to contribute to T cell exclusion, and anti-TGF-β improves anti-PD-L1 efficacy in vivo. However, TGF-β inhibition has frequently been shown to induce toxicity in the clinic, and the clinical efficacy of combination PD-L1 and TGF-β blockade has not yet been proven. To identify strategies to overcome resistance to PD-L1 blockade, the transcriptional programs associated with PD-L1 and/or TGF-β blockade in the tumor microenvironment should be further elucidated. Results We used single-cell RNA sequencing in a mouse model to characterize the transcriptomic effects of PD-L1 and/or TGF-β blockade on nearly 30,000 single cells in the tumor and surrounding microenvironment. Combination treatment led to upregulation of immune response genes, including multiple chemokine genes such as CCL5, in macrophages, and downregulation of extracellular matrix genes in fibroblasts. Analysis of publicly available tumor transcriptome profiles showed that the chemokine CCL5 was strongly associated with immune cell infiltration in various human cancers. Further investigation with in vivo models showed that intratumorally administered CCL5 enhanced cytotoxic lymphocytes and the anti-tumor activity of anti-PD-L1. Conclusions Taken together, our data could be leveraged translationally to complement or find alternatives to anti-PD-L1 plus anti-TGF-β combination therapy, for example through companion biomarkers, and/or to identify novel targets that could be modulated to overcome resistance.

scholarly journals Infino: a Bayesian hierarchical model improves estimates of immune infiltration into tumor microenvironment

2017 ◽  
Author(s):  
Maxim Zaslavsky ◽  
Jacqueline Buros Novik ◽  
Eliza Chang ◽  
Jeffrey Hammerbacher
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
Rna Sequencing ◽  
Immune Cell ◽  
Cell Types ◽  
Training Data ◽  
Cell Type ◽  
Sequencing Data ◽  
Effective Response ◽  
Immune Infiltration

AbstractRobust quantification of immune cell infiltration into the tumor microenvironment may shed light on why only a small proportion of patients benefit from checkpoint therapy. The immune cells surrounding a tumor have been suggested to mediate an effective response to immunotherapy. However, traditional measurement of immune cell content around a tumor by immunohistochemistry, flow cytometry, or mass cytometry allows measurement of only up to a few dozen markers at a time, limiting the number of immune cell types identified. Immune cell type abundances may instead be estimated in silico by deconvolving gene expression mixtures from bulk RNA sequencing of tumor tissue. By measuring tens of thousands of transcripts at once, bulk RNA-seq provides a rich input to algorithms that quantify cell type abundances in the tumor microenvironment, affording the potential to quantify the states of a greater number of immune cell types (given adequate training data). Here, we first review existing methods for deconvolution and evaluate their performance on synthetic mixtures. Then we develop a Bayesian inference approach, named infino, that learns to distinguish immune cell expression phenotypes and deconvolve mixtures. In contrast to earlier approaches, infino accepts RNA sequencing data, models transcript expression variability, and exploits the relationships between cell types to improve deconvolution accuracy and allow interrogation from the level of broad categories to the level of finest granularity. The resulting probability distributions of immune infiltration could be applied to numerous questions concerning the diverse ecology of immune cell types, including assessment of the association of immune infiltration with response to immunotherapy, and study of the expression profile and presence of elusive T cell subcompartments, such as T cell exhaustion.

Generation and Characterization of Microvesicles after Daratumumab Interaction with Myeloma Cells

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1849-1849 ◽  
Author(s):  
Antonella Chillemi ◽  
Valeria Quarona ◽  
Andrea Zito ◽  
Fabio Morandi ◽  
Danilo Marimpietri ◽  
...  
Keyword(s):  
T Cell ◽  
Nk Cells ◽  
Cho Cells ◽  
Research Funding ◽  
Cell Membranes ◽  
Cell Types ◽  
Phase Iii ◽  
Human Igg ◽  
Myeloma Cells

Abstract Daratumumab (DARA) is an anti-CD38 human mAb in phase III clinical trials in myeloma patients. DARA binding induces killing of tumor cells via complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP) and apoptosis. This work reports on the results obtained while dissecting the events following in vivo CD38 ligation by DARA. Treatment of myeloma cells with DARA + anti-human IgG at 37 °C influenced myeloma cytoskeleton, with redistribution of the CD38 molecules and a formation of distinct polar aggregates visualized by confocal microscopy. DARA effects are different from those observed using 8 different murine anti-human CD38 mAbs, which tended to internalize. The findings observed after DARA ligation were confirmed by exposing myeloma cells to DARA immobilized on CHO cells modified to express 4 distinct human FcRs. CHO cells adhere to plastic and mimics the events that take place in the myeloma niche. First, the interaction between Dara and the different FcRs was determined according to a biosensor-based approach on an IAsys Plus equipment (Affinity Sensors). Results show that DARA possesses the highest avidity for CD64, due to the higher kinetic stability of the complex. Conversely, the differences in the FcR-DARA recognition phase (kass) had only minor effects on final stability of the complex. The results also indicated that NK cells and monocytes are the blood populations with higher kdiss for DARA. The effects observed at 37 °C on myeloma cells in the presence of immobilized DARA were amplified when compared to those with soluble mAb. Results indicate that DARA induces CD38 target to aggregate, polarize and to release microvesicles (MV) from extrusions of the myeloma membrane. MV in culture supernatants and in bone marrow plasma of myeloma patients were characterized for concentration (particles/ml) and size by means of Malvern NanoSight NS300 equipment. DARA treatment was followed by high amounts of MV of different sizes released from myeloma cells. Same experiments repeated using DARA + anti-human IgG labeled with Alexa 488 analyzed by Malvern equipment highlighted the presence of DARA on the surface of MV. The induction of MV may be relevant for in vivo therapy: MV are outward buds of the membrane, which host molecules clustered in microdomains. The presence of CD38 has been confirmed. MV phenotype was analyzed looking for the ectoenzymes that join CD38 in the regulation of adenosine in the myeloma niche. MV phenotype included not only the presence of the expected CD38, but also of CD203a/PC-1, CD39 and CD73, the ectoenzymatic pathway leading to ADO production. A first conclusion is that DARA treatment is followed in vivo by a marked release of MV at the tumor site. The fate of the MV bearing DARA on their surface is multiple: on one side, MV may interact locally with different cells and populations of the niche. Another possibility is that MV are released into the blood stream and interact with cell populations therein. The lipid bilayer of MV consents passive movements even through tissues. MV appear as minicellular signals delivering instructions at a distance from their place of origin. Further, the ectoenzymes analyzed are also involved in cell migration or in interaction with countereceptors (e.g., CD31) expressed by endothelial cells. This issue, was investigated by testing FITC-conjugated DARA on a Laboratory-established human myeloma line. MV-DARA-FITC were then exposed to PBMC preparations obtained from normal donors. The results from a cytofluorimetric analysis highlighted the tendency of the labeled MV to cluster around CD16+ (NK cells) and CD14+ subsets (monocytes). At the moment, it is only possible to conclude that MV are associated with cell membranes, a binding likely mediated by FcRs. Not known yet whether MV interact with other cell types (e.g., macrophages, dendritic cells or lymphocytes). DARA shows a high affinity to FcRs of immune cell types (NK cells, monocytes, B cells). Given clinical data that indicate a robust increase in T cell counts, activation and clonality following DARA treatment should be expected. MV containing DARA and portions of myeloma cell membranes could help drive antigen presentation and T cell response in some patients. This is being investigated further. Disclosures Mark: Bioinvent International: Consultancy, Research Funding. Giuliani:Janssen Pharmaceutica: Research Funding; Celgene Italy: Research Funding. Sasser:Janssen Pharmaceuticals: Employment. Malavasi:Janssen: Honoraria, Research Funding.

scholarly journals Hijacked Immune Cells in the Tumor Microenvironment: Molecular Mechanisms of Immunosuppression and Cues to Improve T Cell-Based Immunotherapy of Solid Tumors

2021 ◽  
Vol 22 (11) ◽  
pp. 5736
Author(s):  
Emre Balta ◽  
Guido H. Wabnitz ◽  
Yvonne Samstag
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
Immune Cells ◽  
Molecular Mechanisms ◽  
Immune Cell ◽  
Cell Communication ◽  
Cell Types ◽  
Soluble Factors ◽  
Recent Developments ◽  
Fundamental Reason

The understanding of the tumor microenvironment (TME) has been expanding in recent years in the context of interactions among different cell types, through direct cell–cell communication as well as through soluble factors. It has become evident that the development of a successful antitumor response depends on several TME factors. In this context, the number, type, and subsets of immune cells, as well as the functionality, memory, and exhaustion state of leukocytes are key factors of the TME. Both the presence and functionality of immune cells, in particular T cells, are regulated by cellular and soluble factors of the TME. In this regard, one fundamental reason for failure of antitumor responses is hijacked immune cells, which contribute to the immunosuppressive TME in multiple ways. Specifically, reactive oxygen species (ROS), metabolites, and anti-inflammatory cytokines have central roles in generating an immunosuppressive TME. In this review, we focused on recent developments in the immune cell constituents of the TME, and the micromilieu control of antitumor responses. Furthermore, we highlighted the current challenges of T cell-based immunotherapies and potential future strategies to consider for strengthening their effectiveness.

scholarly journals C4b-binding protein α-chain enhances antitumor immunity by facilitating the accumulation of tumor-infiltrating lymphocytes in the tumor microenvironment in pancreatic cancer

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Kosuke Sasaki ◽  
Shigetsugu Takano ◽  
Satoshi Tomizawa ◽  
Yoji Miyahara ◽  
Katsunori Furukawa ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
Binding Protein ◽  
Combined Treatment ◽  
Tumor Infiltrating Lymphocytes ◽  
Pdac Cell ◽  
Α Chain ◽  
Infiltrating Lymphocytes

Abstract Background Recent studies indicate that complement plays pivotal roles in promoting or suppressing cancer progression. We have previously identified C4b-binding protein α-chain (C4BPA) as a serum biomarker for the early detection of pancreatic ductal adenocarcinoma (PDAC). However, its mechanism of action remains unclear. Here, we elucidated the functional roles of C4BPA in PDAC cells and the tumor microenvironment. Methods We assessed stromal C4BPA, the C4BPA binding partner CD40, and the number of CD8+ tumor-infiltrating lymphocytes in resected human PDAC tissues via immunohistochemical staining. The biological functions of C4BPA were investigated in peripheral blood mononuclear cells (PBMCs) and human PDAC cell lines. Mouse C4BPA (mC4BPA) peptide, which is composed of 30 amino acids from the C-terminus and binds to CD40, was designed for further in vitro and in vivo experiments. In a preclinical experiment, we assessed the efficacy of gemcitabine plus nab-paclitaxel (GnP), dual immune checkpoint blockades (ICBs), and mC4BPA peptide in a mouse orthotopic transplantation model. Results Immunohistochemical analysis revealed that high stromal C4BPA and CD40 was associated with favorable PDAC prognosis (P=0.0005). Stromal C4BPA strongly correlated with the number of CD8+ tumor-infiltrating lymphocytes (P=0.001). In in vitro experiments, flow cytometry revealed that recombinant human C4BPA (rhC4BPA) stimulation increased CD4+ and CD8+ T cell numbers in PBMCs. rhC4BPA also promoted the proliferation of CD40-expressing PDAC cells. By contrast, combined treatment with gemcitabine and rhC4BPA increased PDAC cell apoptosis rate. mC4BPA peptide increased the number of murine T lymphocytes in vitro and the number of CD8+ tumor-infiltrating lymphocytes surrounding PDAC tumors in vivo. In a preclinical study, GnP/ICBs/mC4BPA peptide treatment, but not GnP treatment, led to the accumulation of a greater number of CD8+ T cells in the periphery of PDAC tumors and to greater tumor regression than did control treatment. Conclusions These findings demonstrate that the combination of GnP therapy with C4BPA inhibits PDAC progression by promoting antitumor T cell accumulation in the tumor microenvironment.

scholarly journals Anti-tumor effects of RTX-240: an engineered red blood cell expressing 4-1BB ligand and interleukin-15

2021 ◽  
Author(s):  
Shannon L. McArdel ◽  
Anne-Sophie Dugast ◽  
Maegan E. Hoover ◽  
Arjun Bollampalli ◽  
Enping Hong ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Blood Cell ◽  
Nk Cells ◽  
Red Blood Cell ◽  
Safety Profile ◽  
Nk Cell ◽  
Cell Activity ◽  
In Vivo Studies

AbstractRecombinant agonists that activate co-stimulatory and cytokine receptors have shown limited clinical anticancer utility, potentially due to narrow therapeutic windows, the need for coordinated activation of co-stimulatory and cytokine pathways and the failure of agonistic antibodies to recapitulate signaling by endogenous ligands. RTX-240 is a genetically engineered red blood cell expressing 4-1BBL and IL-15/IL-15Rα fusion (IL-15TP). RTX-240 is designed to potently and simultaneously stimulate the 4-1BB and IL-15 pathways, thereby activating and expanding T cells and NK cells, while potentially offering an improved safety profile through restricted biodistribution. We assessed the ability of RTX-240 to expand and activate T cells and NK cells and evaluated the in vivo efficacy, pharmacodynamics and tolerability using murine models. Treatment of PBMCs with RTX-240 induced T cell and NK cell activation and proliferation. In vivo studies using mRBC-240, a mouse surrogate for RTX-240, revealed biodistribution predominantly to the red pulp of the spleen, leading to CD8 + T cell and NK cell expansion. mRBC-240 was efficacious in a B16-F10 melanoma model and led to increased NK cell infiltration into the lungs. mRBC-240 significantly inhibited CT26 tumor growth, in association with an increase in tumor-infiltrating proliferating and cytotoxic CD8 + T cells. mRBC-240 was tolerated and showed no evidence of hepatic injury at the highest feasible dose, compared with a 4-1BB agonistic antibody. RTX-240 promotes T cell and NK cell activity in preclinical models and shows efficacy and an improved safety profile. Based on these data, RTX-240 is now being evaluated in a clinical trial.

scholarly journals THER-09. ONCOLYTIC ADENOVIRUS, DNX-2401, FOR NAIVE DIFFUSE INTRINSIC PONTINE GLIOMAS: A PHASE I CLINICAL TRIAL

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii473-iii473
Author(s):  
Ignacio Iñigo-Marco ◽  
Marisol Gonzalez-Huarriz ◽  
Marc García-Moure ◽  
Ibon Tamayo ◽  
Sandra Hervas ◽  
...  
Keyword(s):  
T Cell ◽  
Neutralizing Antibodies ◽  
Immune Cell ◽  
Combined Treatment ◽  
Intratumoral Injection ◽  
Post Treatment ◽  
Virus Infectivity ◽  
Tumor Biopsy ◽  
Functional Studies ◽  
Cell Diversity

Abstract The objective of this trial is to determine the safety, tolerability, and toxicity of DNX-2401 in newly diagnosed DIPG patients (NCT03178032) followed by radiotherapy. Secondary endpoints are overall survival at 12 months, percentage of responses and induced immune response against tumor. Tumor biopsy was performed through the cerebellar peduncle, followed by intratumoral injection of DNX-2401 (N=12). Three patients were treated with 1x1010vp and given the lack of toxicity we escalated to 5x1010vp. The procedure was well tolerated and reduced tumor volume was demonstrated in all patients after combined treatment (virus + radiotherapy). We performed molecular studies (RNAseq and the Oncomine Childhood Research Panel from Thermo Fisher). The immune cell composition of the biopsies pre-virus injection was assessed using multiplexed quantitative immunofluorescence. T cells were hardly detectable in these tumors while macrophages were abundant. Using a multiplexed TCR-sequencing mRNA-based assay to analyze 18 available paired pre- and post-treatment samples from the trial, we detected increased clonal T cell diversity following treatment with the virus. We also measured pre and post treatment neutralizing antibodies and their relationship with survival. Finally, we performed functional studies using 2 cell lines isolated from patients included in this trial to assess the response to the virus (infectivity, viability, T-cell recognition). In summary, the virus has shown safety and efficacy in some patients. The information obtained in this clinical study would aid understanding the response of DIPG patients to viral therapies and, therefore, to better tailor this strategy to improve the survival of these patients.

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