scholarly journals CD19-CAR-T Cells Bearing a KIR/PD-1-Based Inhibitory CAR Eradicate CD19+HLA-C1− Malignant B Cells While Sparing CD19+HLA-C1+ Healthy B Cells

Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2612
Author(s):  
Lei Tao ◽  
Muhammad Asad Farooq ◽  
Yaoxin Gao ◽  
Li Zhang ◽  
Congyi Niu ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Killer Cell ◽  
Xenograft Model ◽  
Sustained Remission ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T

B cell aplasia caused by “on-target off-tumor” toxicity is one of the clinical side effects during CD19-targeted chimeric antigen receptor (CAR) T (CD19-CAR-T) cells treatment for B cell malignancies. Persistent B cell aplasia was observed in all patients with sustained remission, which increased the patients’ risk of infection. Some patients even died due to infection. To overcome this challenge, the concept of incorporating an inhibitory CAR (iCAR) into CAR-T cells was introduced to constrain the T cells response once an “on-target off-tumor” event occurred. In this study, we engineered a novel KIR/PD-1-based inhibitory CAR (iKP CAR) by fusing the extracellular domain of killer cell immunoglobulin-like receptors (KIR) 2DL2 (KIR2DL2) and the intracellular domain of PD-1. We also confirmed that iKP CAR could inhibit the CD19 CAR activation signal via the PD-1 domain and CD19-CAR-T cells bearing an iKP CAR (iKP-19-CAR-T) exerted robust cytotoxicity in vitro and antitumor activity in the xenograft model of CD19+HLA-C1− Burkitt’s lymphoma parallel to CD19-CAR-T cells, whilst sparing CD19+HLA-C1+ healthy human B cells both in vitro and in the xenograft model. Meanwhile, iKP-19-CAR-T cells exhibited more naïve, less exhausted phenotypes and preserved a higher proportion of central memory T cells (TCM). Our data demonstrates that the KIR/PD-1-based inhibitory CAR can be a promising strategy for preventing B cell aplasia induced by CD19-CAR-T cell therapy.

scholarly journals 221 CRISPR screen identifies loss of IFNγR signaling and downstream adhesion as a resistance mechanism to CAR T-cell cytotoxicity in solid but not liquid tumors

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A234-A234
Author(s):  
Rebecca Larson ◽  
Michael Kann ◽  
Stefanie Bailey ◽  
Nicholas Haradhvala ◽  
Kai Stewart ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Solid Tumors ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

BackgroundChimeric Antigen Receptor (CAR) therapy has had a transformative impact on the treatment of hematologic malignancies1–6 but success in solid tumors remains elusive. We hypothesized solid tumors have cell-intrinsic resistance mechanisms to CAR T-cell cytotoxicity.MethodsTo systematically identify resistance pathways, we conducted a genome-wide CRISPR knockout screen in glioblastoma cells, a disease where CAR T-cells have had limited efficacy.7 8 We utilized the glioblastoma cell line U87 and targeted endogenously expressed EGFR with CAR T-cells generated from 6 normal donors for the screen. We validated findings in vitro and in vivo across a variety of human tumors and CAR T-cell antigens.ResultsLoss of genes in the interferon gamma receptor (IFNγR) signaling pathway (IFNγR1, JAK1, JAK2) rendered U87 cells resistant to CAR T-cell killing in vitro. IFNγR1 knockout tumors also showed resistance to CAR T cell treatment in vivo in a second glioblastoma line U251 in an orthotopic model. This phenomenon was irrespective of CAR target as we also observed resistance with IL13Ralpha2 CAR T-cells. In addition, resistance to CAR T-cell cytotoxicity through loss of IFNγR1 applied more broadly to solid tumors as pancreatic cell lines targeted with either Mesothelin or EGFR CAR T-cells also showed resistance. However, loss of IFNγR signaling did not impact sensitivity of liquid tumor lines (leukemia, lymphoma or multiple myeloma) to CAR T-cells in vitro or in an orthotopic model of leukemia treated with CD19 CAR. We isolated the effects of decreased cytotoxicity of IFNγR1 knockout glioblastoma tumors to be cancer-cell intrinsic because CAR T-cells had no observable differences in proliferation, activation (CD69 and LFA-1), or degranulation (CD107a) when exposed to wildtype versus knockout tumors. Using transcriptional profiling, we determined that glioblastoma cells lacking IFNγR1 had lower upregulation of cell adhesion pathways compared to wildtype glioblastoma cells after exposure to CAR T-cells. We found that loss of IFNγR1 reduced CAR T-cell binding avidity to glioblastoma.ConclusionsThe critical role of IFNγR signaling for susceptibility of solid tumors to CAR T-cells is surprising given that CAR T-cells do not require traditional antigen-presentation pathways. Instead, in glioblastoma tumors, IFNγR signaling was required for sufficient adhesion of CAR T-cells to mediate productive cytotoxicity. Our work demonstrates that liquid and solid tumors differ in their interactions with CAR T-cells and suggests that enhancing T-cell/tumor interactions may yield improved responses in solid tumors.AcknowledgementsRCL was supported by T32 GM007306, T32 AI007529, and the Richard N. Cross Fund. ML was supported by T32 2T32CA071345-21A1. SRB was supported by T32CA009216-38. NJH was supported by the Landry Cancer Biology Fellowship. JJ is supported by a NIH F31 fellowship (1F31-MH117886). GG was partially funded by the Paul C. Zamecnik Chair in Oncology at the Massachusetts General Hospital Cancer Center and NIH R01CA 252940. MVM and this work is supported by the Damon Runyon Cancer Research Foundation, Stand Up to Cancer, NIH R01CA 252940, R01CA238268, and R01CA249062.ReferencesMaude SL, et al. Tisagenlecleucel in children and young adults with B-cell lymphoblastic leukemia. N Engl J Med 2018;378:439–448.Neelapu SS, et al. Axicabtagene ciloleucel CAR T-cell therapy in refractory large B-cell lymphoma. N Engl J Med 2017;377:2531–2544.Locke FL, et al. Long-term safety and activity of axicabtagene ciloleucel in refractory large B-cell lymphoma (ZUMA-1): a single-arm, multicentre, phase 1–2 trial. The Lancet Oncology 2019;20:31–42.Schuster SJ, et al. Chimeric antigen receptor T cells in refractory B-cell lymphomas. N Engl J Med 2017;377:2545–2554.Wang M, et al. KTE-X19 CAR T-cell therapy in relapsed or refractory mantle-cell lymphoma. N Engl J Med 2020;382:1331–1342.Cohen AD, et al. B cell maturation antigen-specific CAR T cells are clinically active in multiple myeloma. J Clin Invest 2019;129:2210–2221.Bagley SJ, et al. CAR T-cell therapy for glioblastoma: recent clinical advances and future challenges. Neuro-oncology 2018;20:1429–1438.Choi BD, et al. Engineering chimeric antigen receptor T cells to treat glioblastoma. J Target Ther Cancer 2017;6:22–25.Ethics ApprovalAll human samples were obtained with informed consent and following institutional guidelines under protocols approved by the Institutional Review Boards (IRBs) at the Massachusetts General Hospital (2016P001219). Animal work was performed according to protocols approved by the Institutional Animal Care and Use Committee (IACUC) (2015N000218 and 2020N000114).

scholarly journals A Mathematical Description of the Bone Marrow Dynamics of CAR T-Cell Therapy in B-cell Childhood Acute Lymphoblastic Leukemia

2021 ◽  
Author(s):  
Álvaro Martínez-Rubio ◽  
Salvador Chulián ◽  
Cristina Blázquez Goñi ◽  
Antonio Pérez Martínez ◽  
Manuel Ramírez Orellana ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cells ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell Therapy ◽  
Car T

Chimeric Antigen Receptor (CAR) T-cell therapy has demonstrated high rates of response in recurrent B-cell Acute Lymphoblastic Leukemia in children and young adults. Despite this success, a fraction of patients experience relapse after treatment. Relapse is often preceded by recovery of healthy B cells, which suggests loss or dysfunction of CAR T cells in bone marrow. This site is harder to access, and thus is not monitored as frequently as peripheral blood. Understanding the interplay between B cells, leukemic cells and CAR T cells in bone marrow is paramount in ascertaining the causes of lack of response. In this paper, we put forward a mathematical model representing the interaction between constantly renewing B cells, CAR T cells and leukemic cells in the bone marrow. Our model accounts for the maturation dynamics of B cells and incorporates effector and memory CAR T cells. The model provides a plausible description of the dynamics of the various cellular compartments in bone marrow after CAR T infusion. After exploration of the parameter space, we found that the dynamics of CAR T product and disease were independent of the dose injected, initial B-cell load and tumor burden. We also show theoretically the importance of CAR T product attributes in determining therapy outcome, and have studied a variety of possible response scenarios, including second dosage schemes. We conclude by setting out ideas for the refinement of the model.

scholarly journals A Mathematical Description of the Bone Marrow Dynamics during CAR T-Cell Therapy in B-Cell Childhood Acute Lymphoblastic Leukemia

2021 ◽  
Vol 22 (12) ◽  
pp. 6371
Author(s):  
Álvaro Martínez-Rubio ◽  
Salvador Chulián ◽  
Cristina Blázquez Blázquez Goñi ◽  
Manuel Ramírez Ramírez Orellana ◽  
Antonio Pérez Pérez Martínez ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Lymphoblastic Leukemia ◽  
Leukemic Cells ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell Therapy ◽  
Car T

Chimeric Antigen Receptor (CAR) T-cell therapy has demonstrated high rates of response in recurrent B-cell Acute Lymphoblastic Leukemia in children and young adults. Despite this success, a fraction of patients’ experience relapse after treatment. Relapse is often preceded by recovery of healthy B cells, which suggests loss or dysfunction of CAR T-cells in bone marrow. This site is harder to access, and thus is not monitored as frequently as peripheral blood. Understanding the interplay between B cells, leukemic cells, and CAR T-cells in bone marrow is paramount in ascertaining the causes of lack of response. In this paper, we put forward a mathematical model representing the interaction between constantly renewing B cells, CAR T-cells, and leukemic cells in the bone marrow. Our model accounts for the maturation dynamics of B cells and incorporates effector and memory CAR T-cells. The model provides a plausible description of the dynamics of the various cellular compartments in bone marrow after CAR T infusion. After exploration of the parameter space, we found that the dynamics of CAR T product and disease were independent of the dose injected, initial B-cell load, and leukemia burden. We also show theoretically the importance of CAR T product attributes in determining therapy outcome, and have studied a variety of possible response scenarios, including second dosage schemes. We conclude by setting out ideas for the refinement of the model.

Suppression of EBV-induced LCLs using CAR T cells redirected against HLA-DR.

2017 ◽  
Vol 35 (7_suppl) ◽  
pp. 146-146
Author(s):  
Chungyong Han ◽  
Rohit Singh ◽  
Seon-Hee Kim ◽  
Beom K. Choi ◽  
Byoung S. Kwon
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Side Effect ◽  
B Cell Malignancies ◽  
Car T Cells ◽  
Hla Dr ◽  
Car T

146 Background: Recent studies demonstrated a therapeutic potential of T cells with chimeric antigen receptor (CAR) targeting CD19 in refractory B cell malignancies. However, CD19-CAR T cells frequently caused on-target off-tumor side effect, i.e. B cell aplasia, and led to the recurrence of CD19-negative leukemic cells. Alternative target antigen for B cell malignancies has to be excavated. Methods: We developed antibody clone, MVR, which specifically bound to HLA-DR that is highly expressed on malignant B cells. In particular, MVR recognized polymorphic region of HLA-DR, and indicated different binding affinity against various HLA-DR alleles. Based on MVR binding strength, PBMCs from high binder (MVRHigh) and low binder (MVRLow) were tested to generate MVR-CAR T cells. To evaluate the anti-tumor efficacy on B cell malignancies, MVR-CAR T cells were assessed for immune responses against Epstein-Barr virus (EBV)-induced lymphoblastoid cell line (LCL) in vitro and in vivo. Results: Final yield of MVR-CAR T cells generated from MVRHigh PBMCs was 10-fold lower than that of CD19-CAR T cells, presumably caused by "fratricide" among HLA-DR-upregulated MVR-CAR T cells. In contrast, fratricidal effect was ameliorated in MVR-CAR T cells generated from MVRLow PBMCs indicating that the interaction between MVR-CAR and MVRLow-HLA-DR was weak enough to achieve tolerance to fratricide. Of note, in spite of such low binding, MVRLow-LCLs were killed efficiently by the CAR T cells. Further quantitative analysis revealed that HLA-DR was far more upregulated on LCLs compared with normal T and B cells which did not undergo EBV-transformation. In accordance with this observation, MVR-CAR T cells successfully induced LCL-specific cytotoxicity without causing normal B cell damage in vitro and efficiently suppressed the outgrowth of metastasized tumors in LCL-xenografted immune-deficient mice. Conclusions: MVR-CAR T cells redirected against HLA-DR for B cell malignancies were evaluated for the cytotoxic efficacy in vitro and in vivo. Considering the alleviated on-target off-tumor side effect and the feasibility of targeting HLA-DR for CD19-deficient malignant B cells, MVR-CAR T cells can be an alternative option for B cell malignancies.

scholarly journals Ligand Based CAR T-Cell Targeting BAFF Receptors Asa Novel Therapy for B Cell Malignancies

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 31-32
Author(s):  
Reshmi Parameswaran ◽  
Derek Wong ◽  
Keman Zhang ◽  
Abhishek Asthana ◽  
Marcos de Lima ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Research Funding ◽  
Advisory Board ◽  
B Cell Malignancies ◽  
Car T Cells ◽  
Car T

Background: Autologous T cells engineered to express chimeric antigen receptors (CARs) targeting CD19 have shown rapid and durable responses in B cell malignancies. Although CD19 CAR-T cells have demonstrated remarkable success, CD19-negative relapses occur in 30-45% of patients, highlighting the need for adoptive immunotherapies with alternative targeting approaches. B-cell activating factor (BAFF) is a critical B cell survival factor. Receptors of BAFF (BAFF-R, TACI and BCMA) are expressed by a wide range of B cell neoplasms, including ALL, CLL, NHL and MM, making them attractive therapeutic targets. We developed a novel ligand-based CAR that when expressed in T cells, targets and eliminates malignant B cells expressing BAFF receptors (BAFF CAR-T). This approach has several potential advantages over CD19 targeting CAR-T therapy: CD19 is expressed on all B cells, but BAFF receptors are expressed only on mature B cells, making it a more specific antigen for targeting and potentially narrowing down the side effect profile. BAFF CAR-T cells are a potential therapeutic strategy to treat CD19 CAR-T relapsed patients as well as chemotherapy resistant patients. Methods: BAFF ligand was fused to a second generation CAR backbone containing 4-1BB costimulatory and CD3ζ intracellular signaling domains. T cells were isolated from human blood, activated and transduced with BAFF-CAR lentiviral particles. In vitro tumor cell killing was analyzed using calcein-AM cytotoxicity assay. For in vivo testing of BAFF CAR-T cytotoxicity, we used mantle cell lymphoma (MCL) Jeko-1 xenograft model. Immunocompromised NSG mice were subcutaneously injected with human MCL cell line Jeko-1 (10.106 cells at day 0). Once these mice developed measurable tumors, we injected T cells transduced with empty vector (control T cells) or BAFF-CAR T cells (10 x 106 cells) or PBS intra-tumorally as a one-time injection. Tumor volumes were measured every other day using calipers. Results: BAFF CAR-T cells showed significant cytotoxicity in vitro (not shown) and in vivo against human MCL cell line Jeko-1. Mice treated with BAFF-CAR-T showed significant reduction in tumor volume compared to mice treated with control T cells and PBS (Figure 1A, B). Tumor progression was observed after control T cell and PBS treatment, whereas the cohort treated with BAFF CAR-T did not show any tumor progression, and with complete or near-complete tumor eradication. Survival analysis showed the BAFF CAR-T treated cohort had significantly longer survival compared to control-T cell and PBS treated cohorts (Figure 1C). Mice were sacrificed when tumor volume reached 2 cm3. Conclusion: Our data suggest that targeting BAFF receptors with a novel, ligand-based BAFF-CAR-T is a feasible and effective immunotherapeutic strategy to eliminate malignant B cells, warranting further development. BAFF-CAR-T cells have therapeutic potential against a wide spectrum of B cell malignancies, including CD19 negative relapsed disease. Clinical grade expansion and clinical trials are in development for BAFF CAR-T therapy non Hodgkin lymphoma patients. Disclosures Parameswaran: Luminary Therapeutics: Consultancy; Luminary therapeutics: Research Funding. de Lima:Kadmon: Other: Personal Fees, Advisory board; BMS: Other: Personal Fees, advisory board; Incyte: Other: Personal Fees, advisory board; Celgene: Research Funding; Pfizer: Other: Personal fees, advisory board, Research Funding. Caimi:Amgen: Other: Advisory Board; Bayer: Other: Advisory Board; Verastem: Other: Advisory Board; Kite pharmaceuticals: Other: Advisory Board; ADC therapeutics: Other: Advisory Board, Research Funding; Celgene: Speakers Bureau.

A phase I trial using CD19 CAR-T expressing PD-1/CD28 chimeric switch-receptor for refractory or relapsed B-cell lymphoma.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 7557-7557 ◽  
Author(s):  
Hui Liu ◽  
Wen Lei ◽  
Chaoting Zhang ◽  
Chunmei Yang ◽  
Juying Wei ◽  
...  
Keyword(s):  
T Cells ◽  
Phase I ◽  
B Cell ◽  
Cell Lymphoma ◽  
Xenograft Model ◽  
B Cell Lymphoma ◽  
Full Potential ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T

7557 Background: The anti-CD19 chimeric antigen receptor (CAR)-T cell therapy has established efficacy in the treatment of refractory or relapsed (R/R) B-cell lymphoma. However, the existence of different immunosuppressive pathways such PD-1/PD-L1 pathway can restrict the full potential of CAR-T therapy. A recent study demonstrates that a novel PD-1/CD28 chimeric switch-receptor, comprising the extracellular domain of PD-1 and the transmembrane and cytoplasmic signaling domains of CD28, can be used a modality for augmenting antitumor activity of mesothelin- and prostate specific cancer antigen-specific CAR-T cells in either pleural mesothelioma or prostate cancer xenograft model. Here, we describe the first human trial of CD19-PD-1/CD28-CAR-T cells (a CD19-specific CAR-T expressing PD-1/CD28 chimeric switch-receptor) to evaluate safety and efficacy. Methods: This phase I, single-arm, open-label, multicenter trial enrolled patients (18-75 years) with R/R large B-cell lymphoma. PD-L1 expression was confirmed by immunohistochemistry using an anti-PD-L1 mAb (SP142), and confirmed by the review committee with a central evaluation. Seventeen patients received conditioning chemotherapy (cyclophosphamide [500 mg/m2] and fludarabine [30 mg/m2] on days -5, -4 and -3) and followed by CD19-PD-1/CD28-CART cells infusion at doses ranging 0.5 to 4 × 106 CAR+ T cells/kg on day 0. Response was assessed by F-FDG PET/CT at month 3 after CAR-T infusion, according to the International Working Group Response Criteria for Malignant Lymphoma, and duration of response was evaluated by ultrasonic and computed tomography every three months from month 3 to month 12. Results: At data cutoff, 17 patients had received CD19-PD-1/CD28-CART cells. Overall PD-L1 positivity was 15/17 (88.2%) and the mean percentage of PD-L1 positivity was 19.7% (range, 5-50%). Fourteen patients (82.35%) developed cytokine release syndrome (grade ≤ 2) and four (23.53%) developed neurotoxicity (grade = 1), which was reversible in all. The overall response rate was 58.8% (10/17) and complete remission rate was 41.2% (7/17). At a median follow-up 5 months, median overall survival for all patients was not reached. Conclusions: This trial showed the feasibility, controllable toxicities, and effective activity of CD19-PD-1/CD28-CART cells for treating patients with R/R B-cell lymphoma, providing the first proof-of-principle of the potential therapeutic value of targeting the PD-1/PD-L1 pathway in lymphoma in the clinical setting. Clinical trial information: NCT03258047.

scholarly journals TGF-β/IL-7 Chimeric Switch Receptor-Expressing CAR-T Cells Inhibit Recurrence of CD19-Positive B Cell Lymphoma

2021 ◽  
Vol 22 (16) ◽  
pp. 8706
Author(s):  
Kyung-Eun Noh ◽  
Jun-Ho Lee ◽  
So-Yeon Choi ◽  
Nam-Chul Jung ◽  
Ji-Hee Nam ◽  
...  
Keyword(s):  
T Cells ◽  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Single Chain ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T

Chimeric antigen receptor (CAR)-T cells are effective in the treatment of hematologic malignancies but have shown limited efficacy against solid tumors. Here, we demonstrated an approach to inhibit recurrence of B cell lymphoma by co-expressing both a human anti-CD19-specific single-chain variable fragment (scFv) CAR (CD19 CAR) and a TGF-β/IL-7 chimeric switch receptor (tTRII-I7R) in T cells (CD19 CAR-tTRII-I7R-T cells). The tTRII-I7R was designed to convert immunosuppressive TGF-β signaling into immune-activating IL-7 signaling. The effect of TGF-β on CD19 CAR-tTRII-I7R-T cells was assessed by western blotting. Target-specific killing by CD19 CAR-tTRII-I7R-T cells was evaluated by Eu-TDA assay. Daudi tumor-bearing NSG (NOD/SCID/IL2Rγ-/-) mice were treated with CD19 CAR-tTRII-I7R-T cells to analyze the in vivo anti-tumor effect. In vitro, CD19 CAR-tTRII-I7R-T cells had a lower level of phosphorylated SMAD2 and a higher level of target-specific cytotoxicity than controls in the presence of rhTGF-β1. In the animal model, the overall survival and recurrence-free survival of mice that received CD19 CAR-tTRII-I7R-T cells were significantly longer than in control mice. These findings strongly suggest that CD19 CAR-tTRII-I7R-T cell therapy provides a new strategy for long-lasting, TGF-β-resistant anti-tumor effects against B cell lymphoma, which may lead ultimately to increased clinical efficacy.

98 ATA3271: an armored, next-generation off-the-shelf, allogeneic, mesothelin-CAR T cell therapy for solid tumors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A109-A109
Author(s):  
Jiangyue Liu ◽  
Xianhui Chen ◽  
Jason Karlen ◽  
Alfonso Brito ◽  
Tiffany Jheng ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Next Generation ◽  
Phase 3 ◽  
T Cell Therapy ◽  
Cell Therapies ◽  
Car T Cells ◽  
Car T

BackgroundMesothelin (MSLN) is a glycosylphosphatidylinositol (GPI)-anchored membrane protein with high expression levels in an array of malignancies including mesothelioma, ovaria, non-small cell lung cancer, and pancreatic cancers and is an attractive target antigen for immune-based therapies. Early clinical evaluation of autologous MSLN-targeted chimeric antigen receptor (CAR)-T cell therapies for malignant pleural mesothelioma has shown promising acceptable safety1 and have recently evolved with incorporation of next-generation CAR co-stimulatory domains and armoring with intrinsic checkpoint inhibition via expression of a PD-1 dominant negative receptor (PD1DNR).2 Despite the promise that MSLN CAR-T therapies hold, manufacturing and commercial challenges using an autologous approach may prove difficult for widespread application. EBV T cells represent a unique, non-gene edited approach toward an off-the-shelf, allogeneic T cell platform. EBV-specific T cells are currently being evaluated in phase 3 trials [NCT03394365] and, to-date, have demonstrated a favorable safety profile including limited risks for GvHD and cytokine release syndrome.3 4 Clinical proof-of-principle studies for CAR transduced allogeneic EBV T cell therapies have also been associated with acceptable safety and durable response in association with CD19 targeting.5 Here we describe the first preclinical evaluation of ATA3271, a next-generation allogeneic CAR EBV T cell therapy targeting MSLN and incorporating PD1DNR, designed for the treatment of solid tumor indications.MethodsWe generated allogeneic MSLN CAR+ EBV T cells (ATA3271) using retroviral transduction of EBV T cells. ATA3271 includes a novel 1XX CAR signaling domain, previously associated with improved signaling and decreased CAR-mediated exhaustion. It is also armored with PD1DNR to provide intrinsic checkpoint blockade and is designed to retain functional persistence.ResultsIn this study, we characterized ATA3271 both in vitro and in vivo. ATA3271 show stable and proportional CAR and PD1DNR expression. Functional studies show potent antitumor activity of ATA3271 against MSLN-expressing cell lines, including PD-L1-high expressors. In an orthotopic mouse model of pleural mesothelioma, ATA3271 demonstrates potent antitumor activity and significant survival benefit (100% survival exceeding 50 days vs. 25 day median for control), without evident toxicities. ATA3271 maintains persistence and retains central memory phenotype in vivo through end-of-study. Additionally, ATA3271 retains endogenous EBV TCR function and reduced allotoxicity in the context of HLA mismatched targets. ConclusionsOverall, ATA3271 shows potent anti-tumor activity without evidence of allotoxicity, both in vitro and in vivo, suggesting that allogeneic MSLN-CAR-engineered EBV T cells are a promising approach for the treatment of MSLN-positive cancers and warrant further clinical investigation.ReferencesAdusumilli PS, Zauderer MG, Rusch VW, 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 Research 2019;79:CT036-CT036.Kiesgen S, Linot C, Quach HT, et al. Abstract LB-378: Regional delivery of clinical-grade mesothelin-targeted CAR T cells with cell-intrinsic PD-1 checkpoint blockade: Translation to a phase I trial. Cancer Research 2020;80:LB-378-LB-378.Prockop S, Doubrovina E, Suser S, et al. Off-the-shelf EBV-specific T cell immunotherapy for rituximab-refractory EBV-associated lymphoma following transplantation. J Clin Invest 2020;130:733–747.Prockop S, Hiremath M, Ye W, et al. A Multicenter, Open Label, Phase 3 Study of Tabelecleucel for Solid Organ Transplant Subjects with Epstein-Barr Virus-Driven Post-Transplant Lymphoproliferative Disease (EBV+PTLD) after Failure of Rituximab or Rituximab and Chemotherapy. Blood 2019; 134: 5326–5326.Curran KJ, Sauter CS, Kernan NA, et al. Durable remission following ‘Off-the-Shelf’ chimeric antigen receptor (CAR) T-Cells in patients with relapse/refractory (R/R) B-Cell malignancies. Biology of Blood and Marrow Transplantation 2020;26:S89.

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.

scholarly journals Evaluation of chimeric antigen receptor T cell therapy in non-human primates infected with SHIV or SIV

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248973
Author(s):  
Nami Iwamoto ◽  
Bhavik Patel ◽  
Kaimei Song ◽  
Rosemarie Mason ◽  
Sara Bolivar-Wagers ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Chimeric Antigen Receptor ◽  
Viral Suppression ◽  
Antigen Receptor ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T

Achieving a functional cure is an important goal in the development of HIV therapy. Eliciting HIV-specific cellular immune responses has not been sufficient to achieve durable removal of HIV-infected cells due to the restriction on effective immune responses by mutation and establishment of latent reservoirs. Chimeric antigen receptor (CAR) T cells are an avenue to potentially develop more potent redirected cellular responses against infected T cells. We developed and tested a range of HIV- and SIV-specific chimeric antigen receptor (CAR) T cell reagents based on Env-binding proteins. In general, SHIV/SIV CAR T cells showed potent viral suppression in vitro, and adding additional CAR molecules in the same transduction resulted in more potent viral suppression than single CAR transduction. Importantly, the primary determinant of virus suppression potency by CAR was the accessibility to the Env epitope, and not the neutralization potency of the binding moiety. However, upon transduction of autologous T cells followed by infusion in vivo, none of these CAR T cells impacted either acquisition as a test of prevention, or viremia as a test of treatment. Our study illustrates limitations of the CAR T cells as possible antiviral therapeutics.

Sign in / Sign up

Export Citation Format

Share Document