scholarly journals 136 ATA3271: An armored, next-generation off-the-shelf, allogeneic, mesothelin-CAR T cell therapy for solid tumors

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A145-A145
Author(s):  
Xianhui Chen ◽  
Jiangyue Liu ◽  
Shuai Yang ◽  
Amogh Oke ◽  
Sarah Davies ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Next Generation ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

BackgroundMesothelin (MSLN) is a GPI-anchored membrane protein with high expression levels in an array of malignancies including mesothelioma and is an attractive target antigen for tumor surface antigen-targeting therapies. Regional administration of autologous, 2nd generation MSLN-targeted CAR-T cells for malignant pleural mesothelioma has shown promise in early clinical evaluation.1 2 More recently, a next-generation MSLN-targeted, autologous CAR T therapy leveraging 1XX CAR signaling and PD1DNR is currently under investigation for advanced mesothelioma [NCT04577326]. Although autologous MSLN CAR-T holds promise, an allogeneic approach may have more widespread application. EBV T-cells represent a unique, non-gene edited approach for allogeneic T-cell therapy. EBV-specific T-cells are currently in a phase 3 trial for EBV-positive post-transplant lymphoproliferative disease [NCT03394365] and, to-date, have demonstrated a favorable safety profile with no evidence for GvHD and cytokine release syndrome attributable to EBV T-cells. Clinical proof-of-principle studies for CAR transduced CD19-targeted allogeneic EBV T-cell therapies have shown acceptable safety and durable response.3 The first preclinical evaluation of ATA3271 was reported last year.4 Here, we describe updated preclinical data for this potential off-the-shelf, allogeneic cell therapy.MethodsWe engineered MSLN CAR+ EBV T-cells (ATA3271) with a novel 1XX signaling domain that is associated with strong effector function and favorable persistence, as well as armored with PD1DNR to provide intrinsic checkpoint blockade.5 Anti-tumor effect of ATA3271 was assessed using a MSTO-211H-derived tumor cell line overexpressing MSLN and PDL1.ResultsUpon MSLN engagement, ATA3271 showed proliferation, efficient tumor cell lysis in the presence of high-level cell-surface PD-L1 expression and secretion of effector cytokines [IL-2, TNF-α, granzyme B]. In a 16-day serial stimulation assay, with PD-L1+ tumor cells added every 2–3 days, ATA3271 expanded 4 to 45-fold without the need for external cytokines, and retained comparable antitumor function as CD3/CD28-stimulated ‘autologous’ CAR-T cells. In an orthotopic mouse model of pleural mesothelioma, ATA3271 demonstrated anti-tumor efficacy without toxicities. Memory markers [CD62L, CCR7] play a key role for T-cell persistence in vivo. We identified donor-to-donor variability in memory marker expression on ATA3271 and optimized our process to maximize their expression. Memory marker expression impact on ATA3271 potency, both in vitro and in vivo, will be presented.ConclusionsOverall, these in vitro and in vivo data show potent anti-tumor activity without evidence of toxicity, suggesting that ATA3271 may be a promising approach for the treatment of MSLN-positive cancers that warrants further clinical investigation.ReferencesAdusumilli Prasad S, et al. Abstract CT036: A phase I clinical trial of malignant pleural disease treated with regionally delivered autologous mesothelin-targeted CAR T cells: Safety and efficacy. Cancer Res 2019;79(13 Suppl):Abstract CT036.Adusumilli Prasad S, et al. A phase I trial of regional mesothelin-targeted CAR T-cell therapy in patients with malignant pleural disease, in combination with the anti-PD-1 agent pembrolizumab. Cancer Discov 2021.Curran Kevin J, et al. Durable remission following ‘off-the-shelf’ chimeric antigen receptor (CAR) T-cells in patients with relapse/refractory (R/R) B-cell malignancies. Biol Blood Marrow Transplant 2020;26.3: S89.Liu Jiangyue, et al. 98 ATA3271: an armored, next-generation off-the-shelf, allogeneic, mesothelin-CAR T cell therapy for solid tumors. JITC 2020;8.Feucht Judith, et al. Calibration of CAR activation potential directs alternative T cell fates and therapeutic potency. Nat Med 2019;25.1: 82–88.

scholarly journals 124 Functionalizing CAR T cells for selective proliferation and dual-targeting using the meditope technology

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A133-A133
Author(s):  
Cheng-Fu Kuo ◽  
Yi-Chiu Kuo ◽  
Miso Park ◽  
Zhen Tong ◽  
Brenda Aguilar ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

BackgroundMeditope is a small cyclic peptide that was identified to bind to cetuximab within the Fab region. The meditope binding site can be grafted onto any Fab framework, creating a platform to uniquely and specifically target monoclonal antibodies. Here we demonstrate that the meditope binding site can be grafted onto chimeric antigen receptors (CARs) and utilized to regulate and extend CAR T cell function. We demonstrate that the platform can be used to overcome key barriers to CAR T cell therapy, including T cell exhaustion and antigen escape.MethodsMeditope-enabled CARs (meCARs) were generated by amino acid substitutions to create binding sites for meditope peptide (meP) within the Fab tumor targeting domain of the CAR. meCAR expression was validated by anti-Fc FITC or meP-Alexa 647 probes. In vitro and in vivo assays were performed and compared to standard scFv CAR T cells. For meCAR T cell proliferation and dual-targeting assays, the meditope peptide (meP) was conjugated to recombinant human IL15 fused to the CD215 sushi domain (meP-IL15:sushi) and anti-CD20 monoclonal antibody rituximab (meP-rituximab).ResultsWe generated meCAR T cells targeting HER2, CD19 and HER1/3 and demonstrate the selective specific binding of the meditope peptide along with potent meCAR T cell effector function. We next demonstrated the utility of a meP-IL15:sushi for enhancing meCAR T cell proliferation in vitro and in vivo. Proliferation and persistence of meCAR T cells was dose dependent, establishing the ability to regulate CAR T cell expansion using the meditope platform. We also demonstrate the ability to redirect meCAR T cells tumor killing using meP-antibody adaptors. As proof-of-concept, meHER2-CAR T cells were redirected to target CD20+ Raji tumors, establishing the potential of the meditope platform to alter the CAR specificity and overcome tumor heterogeneity.ConclusionsOur studies show the utility of the meCAR platform for overcoming key challenges for CAR T cell therapy by specifically regulating CAR T cell functionality. Specifically, the meP-IL15:sushi enhanced meCAR T cell persistence and proliferation following adoptive transfer in vivo and protects against T cell exhaustion. Further, meP-ritiuximab can redirect meCAR T cells to target CD20-tumors, showing the versatility of this platform to address the tumor antigen escape variants. Future studies are focused on conferring additional ‘add-on’ functionalities to meCAR T cells to potentiate the therapeutic effectiveness of CAR T cell therapy.

Quality Assessment of Pre-Clinical Studies of Chimeric Antigen Receptor T-Cell Therapy Products: A Point of Focus On Safety

2021 ◽  
Vol 16 ◽  
Author(s):  
Vikas Maharshi ◽  
Diksha Diksha ◽  
Pooja Gupta
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Chimeric Antigen Receptor ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Background: Serious adverse reactions have been reported with the use of chimeric antigen receptor (CAR) T-cell therapy in clinical setting despite the success of these products in pre-clinical stages of development. Objective: We evaluated the quality of available pre-clinical safety data of CAR T-cell therapy products. Methods: A 21 items safety-checklist was designed specifically for CAR T-cell. Literature was searched using search/MeSH terms in PubMed (October 2019 – February 2020). Studies were screened from title and abstract. Original pre-clinical researches related to CAR T-cell anti-cancer therapy were included. Results: Of the search results, 152 studies (3 in vivo, 39 in vitro, and 110 combined) were included. Only 7.9% studies were specifically designed to evaluate/ improve product safety. Eleven studies included target antigen(s) and no study included co-stimulatory molecule(s) expressed exclusively by tumor tissue and/or CAR T-cells. One study used CRISPR-Cas9 for CAR gene insertion. The use of switch-off mechanism and purity assessment of CAR T-cell products were reported in 13.2% and 8.6% studies respectively. Of the 149 studies with in vivo component, immuno-competent animal models were used in 24.8%. Measurement of blood pressure, temperature, body weight and serum cytokines were reported in 0, 2.7, 29.2 and 27.4% studies respectively. The tissue distribution and CAR T-cells persistence were reported in 26.5% studies. Conclusion: Majority of the checklist parameters were not reported in the pre-clinical publications to be adequately predictive of the safety of CAR T-cells in a clinical setting.

scholarly journals Targeting hypoxia downstream signaling protein, CAIX, for CAR T-cell therapy against glioblastoma

2019 ◽  
Vol 21 (11) ◽  
pp. 1436-1446 ◽  
Author(s):  
Jing Cui ◽  
Qi Zhang ◽  
Qi Song ◽  
Herui Wang ◽  
Pauline Dmitriev ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Intratumoral Injection ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Abstract Background Glioblastoma survival remains unchanged despite continuing therapeutic innovation. Herein, we aim to (i) develop chimeric antigen receptor (CAR) T cells with a specificity to a unique antigen, carbonic anhydrase IX (CAIX), which is expressed in the hypoxic microenvironment characteristic of glioblastoma, and (ii) demonstrate its efficacy with limited off-target effects. Methods First we demonstrated expression of CAIX in patient-derived glioblastoma samples and available databases. CAR T cells were generated against CAIX and efficacy was assessed in 4 glioblastoma cell lines and 2 glioblastoma stem cell lines. Cytotoxicity of anti-CAIX CAR T cells was assessed via interferon gamma, tumor necrosis factor alpha, and interleukin-2 levels when co-cultured with tumor cells. Finally, we assessed efficacy of direct intratumoral injection of the anti-CAIX CAR T cells on an in vivo xenograft mouse model using the U251 luciferase cell line. Tumor infiltrating lymphocyte analyses were performed. Results We confirm that CAIX is highly expressed in glioblastoma from patients. We demonstrate that CAIX is a suitable target for CAR T-cell therapy using anti-CAIX CAR T cells against glioblastoma in vitro and in vivo. In our mouse model, a 20% cure rate was observed without detectable systemic effects. Conclusions By establishing the specificity of CAIX under hypoxic conditions in glioblastoma and highlighting its efficacy as a target for CAR T-cell therapy, our data suggest that anti-CAIX CAR T may be a promising strategy to treat glioblastoma. Direct intratumoral injection increases anti-CAIX CAR T-cell potency while limiting its off-target effects.

scholarly journals 147 Memory phenotype in allogeneic anti-BCMA CAR-T cell therapy (P-BCMA-ALLO1) correlates with in vivo tumor control

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A155-A155
Author(s):  
Hubert Tseng ◽  
Yan Zhang ◽  
Stacey Cranert ◽  
Maximilian Richter ◽  
Karl Marquez ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
T Cell Therapy ◽  
Memory Phenotype ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

BackgroundThe emergence of CAR-T cell therapy has transformed the treatment of refractory/relapsed multiple myeloma (MM). Yet, autologous CAR-T cells suffer from many manufacturing challenges including mainly consistency, toxicity, and cost. To address these issues, we engineered a fully allogeneic anti-BCMA CAR-T cell candidate for MM from healthy donors (P-BCMA-ALLO1). Herein, we demonstrate that this therapy maintains a stem cell memory T cell (TSCM) phenotype through editing which correlates with in vivo antitumor efficacy.MethodsUsing Poseida’s non-viral piggyBac® (PB) DNA Delivery System in combination with the high-fidelity Cas-CLOVER™ (CC) Site-Specific Gene Editing System and a proprietary ‘booster molecule’, we generated P-BCMA-ALLO1 from healthy donor T cells. We used CC to eliminate surface expression of both the TCR and MHC class I to make fully allogeneic CAR-T cells. In addition to the CAR molecule, PB enables the delivery of a selectable marker allowing the generation of a final cell product that is >95% CAR-positive. The inclusion of the ‘booster molecule’ in the manufacturing process improves the expansion of gene-edited cells without compromising memory phenotype or function. This process can produce up to hundreds of patient doses from a single manufacturing run which significantly reduces manufacturing cost per dose. We characterized the memory phenotype of P-BCMA-ALLO1 by assessing the mRNA and protein expression profiles of rested and activated CAR-T cells by flow cytometry and Nanostring analysis. We also assessed the antitumor capabilities of these cells using cytotoxicity assays and performed serial in vitro restimulation to assess the ability of P-BCMA-ALLO1 to undergo multiple rounds of activation and expansion. We then evaluated the relationship of these characteristics with in vivo efficacy, as defined by control of tumor in an immunodeficient RPMI-8226 subcutaneous murine tumor model.ResultsP-BCMA-ALLO1 is comprised of a high frequency of TSCM. It has potent in vivo antitumor activity, which is comparable to non-edited autologous anti-BCMA CAR-T cell therapy. Expression of memory markers at both mRNA and protein levels across individual lots significantly correlates with in vivo tumor control. Conversely, suboptimal research products with worse in vivo outcomes expressed an exhausted gene expression profile. Moreover, CAR-T products that are more effective in vivo are also more viable, cytotoxic, and proliferative following multiple rounds of restimulation in vitro.ConclusionsP-BCMA-ALLO1 is a highly potent and safe allogeneic anti-BCMA CAR with a manufacturing process that consistently maintains a TSCM phenotype, which correlates with antitumor efficacy. P-BCMA-ALLO1 is advancing rapidly towards the clinic (NCT04960579).

scholarly journals Enhancing the Antigen-Sensitivity of the CD22 CAR through Modulation of the Affinity and Linker-Length of the Single-Chain Fragment Variable

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 41-42
Author(s):  
M. Eric Kohler ◽  
Zachary Walsh ◽  
Kole Degolier ◽  
Terry J. Fry
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

The advent of chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of relapsed/refractory acute lymphoblastic leukemia (r/r ALL). CD19 directed CAR T cells have demonstrated the ability to induce complete remissions in up to 90% of r/r ALL patients. Despite this remarkable upfront success, relapse after CAR T cell therapy remains a major obstacle to long term remissions. A major mechanism for relapse after CD19-directed CAR T cell therapy is the recurrence of antigen-negative ALL cells. In recent years, CD22 CAR T cell therapy has emerged as an effective salvage therapy for patients with CD19-negative ALL. In a phase I clinical trial, CD22 CAR T cells were able to induce remission in up to 80% of patients with CD19-negative ALL. Patients achieving remission, who did not undergo a consolidative hematopoietic stem cell transplant, were found to be at high risk of relapse due to downregulation of the CD22 antigen below the threshold required for effective CD22 CAR T cell activity. Thus, strategies to increase the antigen-sensitivity of CD22 CAR T cells have the potential to enhance the induction and duration of remission in ALL patients. As the properties of a CAR that influence sensitivity to antigen are not well defined, we began by testing the impact of increasing the affinity of the single-chain fragment variable (scFv) for the CD22 antigen. T cells from healthy donors were activated and transduced with a second-generation, 4-1BB CAR containing either the standard affinity (SA)-m971 scFv used in the prior clinical trial, or a high affinity (HA) scFv generated by affinity maturation of the m971 scFv. SA- and HA-CD22 CAR T cells were evaluated in vitro and in vivo against clones of the pre-B ALL cell line, NALM6, which express CD22 at wild type levels (CD22WT), sub-physiologic levels (CD22Lo), supra-physiologic levels (CD22Hi) or in which CD22 was deleted (CD22Neg). We found that the amount of CD22 expressed on the leukemia cells resulted in dose-dependent expression of activation markers, such as CD69 and CD25 (p<0.05) on CD22 CAR T cells. Similarly, CAR T cell functions, such as the secretion of interferon-gamma (IFNg, p<0.0001) and interleukin-2 (IL-2, p<0.0001) as well as cytotoxic degranulation (p<0.0001) were all significantly impacted by the amount of CD22 on the surface of NALM6. A similar pattern of antigenic dose-response was seen in the signaling of CAR T cells, with phosphorylation of ERK reflecting the level of CD22 antigen (p<0.001) and correlating with the increased in vivo efficacy of the CAR T cells against CD22WT NALM6, relative to CD22Lo NALM6. Increasing the affinity of the CD22 CAR did not impact the in vivo efficacy against CD22WT NALM6 at either a therapeutic or subtherapeutic dose, however, HA-CD22 CAR T cells significantly prolonged the survival of NSG mice with CD22Lo NALM6, relative to SA-CD22 CAR T cells (p<0.01). The enhanced activity of HA-CD22 CAR T cells against CD22Lo leukemia did not correlate with improved in vitro functionality, as the HA-CD22 CAR T cells surprisingly demonstrated lower IL-2 secretion (p<0.01), lower proliferation (p<0.05) and diminished in vitro lysis of CD22Lo NALM6 (p<0.05), relative to SA-CD22 CAR T cells. ERK phosphorylation, however, was significantly increased in HA-CD22 CAR T cells (p<0.01) and was the only in vitro marker which correlated with the enhanced in vivo activity seen with the affinity-matured CAR. Previous clinical experience has demonstrated the importance of using a short linker (consisting of a single G4S sequence) between the heavy and light chains of the m971 scFv, therefore we next evaluated the impact of linker length on the activity of the HA-CD22 CAR. HA-CD22 CARs were generated with either a short- or long-linker (G4S x1 vs G4S x3, respectively) and evaluated in vitro and in vivo. While the short linker improved proliferation in vitro, there was no significant impact of linker length on cytokine production or lysis of CD22Lo NALM6. In a xenograft model, HA-CD22 CAR T cells with the long-linker demonstrated slower progression of CD22Lo leukemia and significantly prolonged survival of NSG mice with CD22WT leukemia relative to HA-CD22 CAR T cells with the short-linker (p<0.01). Taken together, these studies suggest that increasing the affinity of a scFv is a promising strategy for enhancing CAR sensitivity to low levels of target antigen, with the potential to decrease post-CAR T cell relapses due to antigen downregulation. Disclosures No relevant conflicts of interest to declare.

scholarly journals Clinical and Product Features Associated with Outcome of DLBCL Patients to CD19-Targeted CAR T-Cell Therapy

Cancers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 4279
Author(s):  
Sylvain Lamure ◽  
François Van Laethem ◽  
Delphine De Verbizier ◽  
Claire Lozano ◽  
Eve Gehlkopf ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
B Cell Lymphoma ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

CD19-directed CAR T-cells have been remarkably successful in treating patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) and transformed follicular lymphoma (t-FL). In this cohort study, we treated 60 patients with axicabtagene ciloleucel or tisagenlecleucel. Complete and partial metabolic responses (CMR/PMR) were obtained in 40% and 23% of patients, respectively. After 6.9 months of median follow-up, median progression-free survival (mPFS) and overall survival (mOS) were estimated at 3.1 and 12.3 months, respectively. Statistical analyses revealed that CMR, PFS, and OS were all significantly associated with age-adjusted international prognostic index (aaIPI, p < 0.05). T-cell subset phenotypes in the apheresis product tended to correlate with PFS. Within the final product, increased percentages of both CD4 and CD8 CAR+ effector memory cells (p = 0.02 and 0.01) were significantly associated with CMR. Furthermore, higher CMR/PMR rates were observed in patients with a higher maximal in vivo expansion of CAR T-cells (p = 0.05) and lower expression of the LAG3 and Tim3 markers of exhaustion phenotype (p = 0.01 and p = 0.04). Thus, we find that aaIPI at the time of infusion, phenotype of the CAR T product, in vivo CAR T-cell expansion, and low levels of LAG3/Tim3 are associated with the efficacy of CAR T-cell therapy in DLBCL patients.

scholarly journals Anti-Mesothelin CAR T cell therapy for malignant mesothelioma

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Laura Castelletti ◽  
Dannel Yeo ◽  
Nico van Zandwijk ◽  
John E. J. Rasko
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Malignant Mesothelioma ◽  
Oncolytic Viruses ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

AbstractMalignant mesothelioma (MM) is a treatment-resistant tumor originating in the mesothelial lining of the pleura or the abdominal cavity with very limited treatment options. More effective therapeutic approaches are urgently needed to improve the poor prognosis of MM patients. Chimeric Antigen Receptor (CAR) T cell therapy has emerged as a novel potential treatment for this incurable solid tumor. The tumor-associated antigen mesothelin (MSLN) is an attractive target for cell therapy in MM, as this antigen is expressed at high levels in the diseased pleura or peritoneum in the majority of MM patients and not (or very modestly) present in healthy tissues. Clinical trials using anti-MSLN CAR T cells in MM have shown that this potential therapeutic is relatively safe. However, efficacy remains modest, likely due to the MM tumor microenvironment (TME), which creates strong immunosuppressive conditions and thus reduces anti-MSLN CAR T cell tumor infiltration, efficacy and persistence. Various approaches to overcome these challenges are reviewed here. They include local (intratumoral) delivery of anti-MSLN CAR T cells, improved CAR design and co-stimulation, and measures to avoid T cell exhaustion. Combination therapies with checkpoint inhibitors as well as oncolytic viruses are also discussed. Preclinical studies have confirmed that increased efficacy of anti-MSLN CAR T cells is within reach and offer hope that this form of cellular immunotherapy may soon improve the prognosis of MM patients.

scholarly journals Metabolic and Mitochondrial Functioning in Chimeric Antigen Receptor (CAR)—T Cells

Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1229
Author(s):  
Ali Hosseini Rad S. M. ◽  
Joshua Colin Halpin ◽  
Mojtaba Mollaei ◽  
Samuel W. J. Smith Bell ◽  
Nattiya Hirankarn ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Chimeric Antigen Receptor ◽  
Metabolic State ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized adoptive cell therapy with impressive therapeutic outcomes of >80% complete remission (CR) rates in some haematological malignancies. Despite this, CAR T cell therapy for the treatment of solid tumours has invariably been unsuccessful in the clinic. Immunosuppressive factors and metabolic stresses in the tumour microenvironment (TME) result in the dysfunction and exhaustion of CAR T cells. A growing body of evidence demonstrates the importance of the mitochondrial and metabolic state of CAR T cells prior to infusion into patients. The different T cell subtypes utilise distinct metabolic pathways to fulfil their energy demands associated with their function. The reprogramming of CAR T cell metabolism is a viable approach to manufacture CAR T cells with superior antitumour functions and increased longevity, whilst also facilitating their adaptation to the nutrient restricted TME. This review discusses the mitochondrial and metabolic state of T cells, and describes the potential of the latest metabolic interventions to maximise CAR T cell efficacy for solid tumours.

IMMU-45. COMBINATION OF EGFRVIII CAR T-CELL THERAPY AND PARACRINE GAM MODULATION FOR THE TREATMENT OF GBM

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi102-vi103
Author(s):  
Tomás A Martins ◽  
Marie-Françoise Ritz ◽  
Tala Shekarian ◽  
Philip Schmassmann ◽  
Deniz Kaymak ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Differential Expression Analysis ◽  
Dependent Manner ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Abstract The GBM immune tumor microenvironment mainly consists of protumoral glioma-associated microglia and macrophages (GAMs). We have previously shown that blockade of CD47, a ‘don't eat me’-signal overexpressed by GBM cells, rescued GAMs' phagocytic function in mice. However, monotherapy with CD47 blockade has been ineffective in treating human solid tumors to date. Thus, we propose a combinatorial approach of local CAR T cell therapy with paracrine GAM modulation for a synergistic elimination of GBM. We generated humanized EGFRvIII CAR T-cells by lentiviral transduction of healthy donor human T-cells and engineered them to constitutively release a soluble SIRPγ-related protein (SGRP) with high affinity towards CD47. Tumor viability and CAR T-cell proliferation were assessed by timelapse imaging analysis in co-cultures with endogenous EGFRvIII-expressing BS153 cells. Tumor-induced CAR T-cell activation and degranulation were confirmed by flow cytometry. CAR T-cell secretomes were analyzed by liquid chromatography-mass spectrometry. Immunocompromised mice were orthotopically implanted with EGFRvIII+ BS153 cells and treated intratumorally with a single CAR T-cell injection. EGFRvIII and EGFRvIII-SGRP CAR T-cells killed tumor cells in a dose-dependent manner (72h-timepoint; complete cytotoxicity at effector-target ratio 1:1) compared to CD19 controls. CAR T-cells proliferated and specifically co-expressed CD25 and CD107a in the presence of tumor antigen (24h-timepoint; EGFRvIII: 59.3±3.00%, EGFRvIII-SGRP: 52.6±1.42%, CD19: 0.1±0.07%). Differential expression analysis of CAR T-cell secretomes identified SGRP from EGFRvIII-SGRP CAR T-cell supernatants (-Log10qValue/Log2fold-change= 3.84/6.15). Consistent with studies of systemic EGFRvIII CAR T-cell therapy, our data suggest that intratumoral EGFRvIII CAR T-cells were insufficient to eliminate BS153 tumors with homogeneous EGFRvIII expression in mice (Overall survival; EGFRvIII-treated: 20%, CD19-treated: 0%, n= 5 per group). Our current work focuses on the functional characterization of SGRP binding, SGRP-mediated phagocytosis, and on the development of a translational preclinical model of heterogeneous EGFRvIII expression to investigate an additive effect of CAR T-cell therapy and GAM modulation.

scholarly journals Feasibility, and Efficacy of Donor-Derived cd19-Targeted Car t-Cell Therapy in Refractory/Relapsed(r/r)b-Cell Acute Lymphoblastic Leukemia (b-all) Patients

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 4-6
Author(s):  
Xian Zhang ◽  
Junfang Yang ◽  
Wenqian Li ◽  
Gailing Zhang ◽  
Yunchao Su ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T ◽  
Grade 3

Backgrounds As CAR T-cell therapy is a highly personalized therapy, process of generating autologous CAR-T cells for each patient is complex and can still be problematic, particularly for heavily pre-treated patients and patients with significant leukemia burden. Here, we analyzed the feasibility and efficacy in 37 patients with refractory/relapsed (R/R) B-ALL who received CAR T-cells derived from related donors. Patients and Methods From April 2017 to May 2020, 37 R/R B-ALL patients with a median age of 19 years (3-61 years), were treated with second-generation CD19 CAR-T cells derived from donors. The data was aggregated from three clinical trials (www.clinicaltrials.gov NCT03173417; NCT02546739; and www.chictr.org.cn ChiCTR-ONC-17012829). Of the 37 patients, 28 were relapsed following allogenic hematopoietic stem cell transplant (allo-HSCT) and whose lymphocytes were collected from their transplant donors (3 HLA matched sibling and 25 haploidentical). For the remaining 9 patients without prior transplant, the lymphocytes were collected from HLA identical sibling donors (n=5) or haploidentical donors (n=4) because CAR-T cells manufacture from patient samples either failed (n=5) or blasts in peripheral blood were too high (&gt;40%) to collect quality T-cells. The median CAR-T cell dose infused was 3×105/kg (1-30×105/kg). Results For the 28 patients who relapsed after prior allo-HSCT, 27 (96.4%) achieved CR within 30 days post CAR T-cell infusion, of which 25 (89.3%) were minimal residual disease (MRD) negative. Within one month following CAR T-cell therapy, graft-versus-host disease (GVHD) occurred in 3 patients including 1 with rash and 2 with diarrhea. A total of 19 of the 28 (67.9%) patients had cytokine release syndrome (CRS), including two patients (7.1%) with Grade 3-4 CRS. Four patients had CAR T-cell related neurotoxicity including 3 with Grade 3-4 events. With a medium follow up of 103 days (1-669days), the median overall survival (OS) was 169 days (1-668 days), and the median leukemia-free survival (LFS) was 158 days (1-438 days). After CAR T-cell therapy, 15 patients bridged into a second allo-HSCT and one of 15 patients (6.7%) relapsed following transplant, and two died from infection. There were 11 patients that did not receive a second transplantation, of which three patients (27.3%) relapsed, and four parents died (one due to relapse, one from arrhythmia and two from GVHD/infection). Two patients were lost to follow-up. The remaining nine patients had no prior transplantation. At the time of T-cell collection, the median bone marrow blasts were 90% (range: 18.5%-98.5%), and the median peripheral blood blasts were 10% (range: 0-70%). CR rate within 30 days post CAR-T was 44.4% (4/9 cases). Six patients developed CRS, including four with Grade 3 CRS. Only one patient had Grade 3 neurotoxicity. No GVHD occurred following CAR T-cell therapy. Among the nine patients, five were treated with CAR T-cells derived from HLA-identical sibling donors and three of those five patients achieved CR. One patient who achieved a CR died from disseminated intravascular coagulation (DIC) on day 16. Two patients who achieved a CR bridged into allo-HSCT, including one patient who relapsed and died. One of two patients who did not response to CAR T-cell therapy died from leukemia. Four of the nine patients were treated with CAR T-cells derived from haploidentical related donors. One of the four cases achieved a CR but died from infection on day 90. The other three patients who had no response to CAR T-cell therapy died from disease progression within 3 months (7-90 days). Altogether, seven of the nine patients died with a median time of 19 days (7-505 days). Conclusions We find that manufacturing CD19+ CAR-T cells derived from donors is feasible. For patients who relapse following allo-HSCT, the transplant donor derived CAR-T cells are safe and effective with a CR rate as high as 96.4%. If a patient did not have GVHD prior to CAR T-cell therapy, the incidence of GVHD following CAR T-cell was low. Among patients without a history of transplantation, an inability to collect autologous lymphocytes signaled that the patient's condition had already reached a very advanced stage. However, CAR T-cells derived from HLA identical siblings can still be considered in our experience, no GVHD occurred in these patients. But the efficacy of CAR T-cells from haploidentical donors was very poor. Disclosures No relevant conflicts of interest to declare.

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