scholarly journals FLT3 Inhibitor Treatment Increases FLT3 Expression That Exposes FLT3-ITD+ AML Blasts to Elimination By FLT3 CAR-T Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 903-903 ◽  
Author(s):  
Hardikkumar Jetani ◽  
Irene García-Cadenas ◽  
Thomas Nerreter ◽  
Ralph Goetz ◽  
Jorge Sierra ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Lines ◽  
Combination Treatment ◽  
Car T Cells ◽  
Flt3 Inhibitor ◽  
Car T ◽  
Flt3 Inhibitors ◽  
Flt3 Expression ◽  
Inhibitor Treatment

Abstract Background: FMS-like tyrosine kinase 3 (FLT3) is a transmembrane protein uniformly expressed on leukemic blasts in acute myeloid leukemia (AML), and driver of leukemia-genesis in FLT3-ITD+ (Internal tandem duplication) AML. There is an increasing body of pre-clinical and clinical data suggesting that FLT3-ITD+ AML blasts respond to FLT3 inhibitor treatment by augmenting FLT3 expression in order to sustain the survival signal provided by this mutation. Here, we analyzed FLT3 expression on FLT3 wild type and FLT3-ITD+ AML cells after treatment with the FLT3 inhibitors midostaurin, quizartinib and crenolanib, and determined the antileukemia efficacy of combination treatment with FLT3 inhibitors and FLT3 CAR T cells in vitro and in vivo. Methods: MOLM-13 and MV4;11 AML cells (both FLT3-ITD+) were cultured in the presence of IC50 doses of midostaurin, quizartinib and crenolanib, respectively to induce resistance (MOLM-13R/MV4;11R). A FLT3-CAR comprised of BV10 scFv binding domain, CD28-CD3ζ signal module and EGFRt marker was encoded in a lentiviral vector and expressed in CD8+ and CD4+ T cells of healthy donors and patients (n=6). T cell mediated cytolytic activity was evaluated in luminescence-based assay, cytokine production analyzed by ELISA and proliferation assessed by CFSE dye dilution. NSG mice (n= 4-6 per group) were engrafted with MOLM-13/ffLuc AML cells and treated with 5x106 CAR T cells alone or in combination with FLT3 inhibitors. Results: We detected a significant increase in FLT3 expression on both MV4;11 and MOLM-13 AML cells after treatment with each of the inhibitors as assessed by mean fluorescence intensity (quizartinib > crenolanib > midostaurin). The increase in FLT3 expression occurred specifically on these FLT3-ITD+ AML cell lines and was not observed on FLT3 wt AML (THP-1), acute lymphoblastic leukemia (NALM-16), mixed lineage leukemia (KOPN-8 and SEM) cell lines and normal hematopoietic stem cells. We applied single molecule sensitive super-resolution microscopy to demonstrate that the average number of FLT3 molecules (per micrometer sq.) on MV4;11 AML cells had increased from 0.80 (untreated) to 10.7 (quizartinib), 4.7 (crenolanib), and 3.3 (midostaurin) (p<.05). Of interest, midostaurin induced clustering of FLT3, while FLT3 was still present as monomers after quizartinib and crenolanib treatment. Intriguingly, the higher FLT3 density after FLT3 inhibitor treatment translated into superior antileukemia reactivity of FLT3 CAR T cells against AML cell lines and primary AML cells in vitro and in vivo. We observed the strongest increase in cytolytic activity, cytokine production and proliferation by CD8+ and CD4+ FLT3 CAR T cells after treatment with crenolanib and quizartinib, followed by midostaurin (p<.05). We confirmed that upregulation of FLT3 occurred on MOLM-13 cells during FLT3 inhibitor therapy in NSG mice in vivo, and observed synergistic antileukemia efficacy of FLT3 CAR T cells in combination with each of the compounds. The mean frequency of FLT3 CAR T cells in mice that received FLT3 CAR T cells and an FLT3 inhibitor was 2-4 fold higher compared to mice had received FLT3 CAR T cells alone (p<.05) and was the highest in the cohort of mice that had received FLT3 CAR T cells in combination with crenolanib. FLT3 CAR T cells alone and each of the combination treatments of FLT3 CAR T & FLT3 inhibitor achieved 100% response rate which compares favorably to untreated or FLT3 inhibitor alone (0%). However, the mean fold reduction in leukemia burden (b/w day 7 and 10) was greater in all three combination treatment compare to only CAR treatment (p<.05). The most potent combination was FLT3 CAR T cells & crenolanib that accomplished the strongest reduction in leukemia burden as assessed by bioluminescence imaging and flow cytometry. Conclusion: Collectively, the data show that FLT3 inhibitors augment cell surface expression of FLT3 in FLT3-ITD+ AML cells which leads to enhanced recognition and elimination by FLT3 CAR T cells. This is, to our knowledge, the first demonstration that small molecule inhibitors and CAR T cell immunotherapy can be used synergistically to treat a hematologic malignancy. We confirmed this principle with each of the FLT3 inhibitors in our panel, and observed the strongest antileukemia activity of FLT3 CAR T cells in combination with crenolanib. Our data encourage the clinical evaluation of this combination treatment in high risk patients with FLT3-ITD+ AML. Disclosures Jetani: University hospital wuerzburg: Employment, Patents & Royalties: H.J. and M.H are co-inventors on a patent related to the use of FLT3-CAR T-cells to treat AML filed by the University of Wuerzburg, Wuerzburg, Germany. Bonig:Kiadis Pharma: Consultancy.

GRP78 Is Expressed on the Cell Surface of Pediatric AML Blasts and Can be Targeted with GRP78-CAR T Cells without Toxicity to Hematopoietic Progenitor Cells

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 12-12 ◽  
Author(s):  
Nikhil Hebbar ◽  
Rebecca Epperly ◽  
Abishek Vaidya ◽  
Sujuan Huang ◽  
Cheng Cheng ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Surface ◽  
Cell Lines ◽  
Target Cells ◽  
Advisory Committees ◽  
Car T Cells ◽  
Car T ◽  
Pediatric Aml

Finding the ideal immunotherapy target for AML has proven challenging and is limited by overlapping expression of antigens on hematopoietic progenitor cells (HPCs) and AML blasts. Intracellular Glucose-regulated-protein 78 (GRP78) is a key UPR regulator, which normally resides in the endoplasmic reticulum (ER). GRP78 is overexpressed and translocated to the cell surface in a broad range of solid tumors and hematological malignancies in response to elevated ER stress, making it an attractive target for immune-based therapies with T cells expressing chimeric antigen receptors (CARs). The goal of this project was to determine the expression of GRP78 on pediatric AML samples, generate GRP78-CAR T cells, and evaluate their effector function against AML blasts in vitro and in vivo. To demonstrate overexpression of GRP78 in AML, we performed gene expression analysis by RNAseq on a cohort of cord blood CD34+ cell samples (N=5) and 74 primary AML samples. Primary AML samples included RUNX1-RUNX1T1 (N=7), CBFB-MYH11(N=17), KMT2A rearrangement (N=28) and NUP98 (N=22). Analysis showed increased GRP78 expression in AML samples, especially in KMT2A- and NUP98-rearranged AML. To demonstrate surface expression of GRP78, we performed flow cytometry of AML (Kg1a, MOLLM13, THP-1, MV4-11) cell lines as well as 11 primary AML samples and 5 PDX samples; non transduced (NT) T cells served as control. All AML samples, including cell lines, primary AML blasts, and PDX samples, showed increased expression of GRP78 on their cell surface in comparison to NT T cells We then designed a retroviral vector encoding a GRP78-CAR using a GRP78-specific peptide as an antigen recognition domain, and generated GRP78-CAR T cells by retroviral transduction of primary human T cells. Median transduction efficiency was 82% (± 5-8%, N=6), and immunophenotypic analysis showed a predominance of naïve and terminal effector memory subsets on day 7 after transduction (N=5). To determine the antigen specificity of GRP78-CAR T cells, we performed coculture assays in vitro with cell surface GRP78+ (AML cell lines: MOLM13, MV-4-11, and THP-1 and 3 AML PDX samples) or cell surface GRP78- (NT T cells) targets. T cells expressing CARs specific for HER2-, CD19-, or a non-functional GRP78 (DGRP78)-CAR served as negative controls. GRP78-CAR T cells secreted significant amounts of IFNg and IL-2 only in the presence of GRP78+ target cells (N=3, p&lt;0.005); while control CAR T cells did not. GRP78-CAR T cells only killed GRP78+ target cells in standard cytotoxicity assays confirming specificity. To test the effects of GRP78-CAR T cells on normal bone marrow derived HPCs, we performed standard colony forming unit (CFU) assays post exposure to GRP78-CAR or NT T cells (effector to target (E:T) ratio 1:1 and 5:1) and determined the number of BFU-E, CFU-E, CFU-GM, and CFU-GEMM. No significant differences between GRP78-CAR and NT T cells were observed except for CFU-Es at an E:T ratio of 5:1 that was not confirmed for BFU-Es. Finally, we evaluated the antitumor activity of GRP78-CAR T cells in an in vivo xenograft AML model (MOLM13). Tumor growth was monitored by serial bioluminescence imaging. A single intravenous dose of GRP78-CAR T cells induced tumor regression, which resulted in a significant (p&lt;0.001) survival advantage in comparison to mice that had received control CAR T cells. In conclusion, GRP78 is expressed on the cell surface of AML. GRP78-CAR T cells have potent anti-AML activity in vitro and in vivo and do not target normal HPCs. Thus, our cell therapy approach warrants further active exploration and has the potential to improve outcomes for patients with AML. Disclosures Hebbar: St. Jude: Patents & Royalties. Epperly:St. Jude: Patents & Royalties. Vaidya:St. Jude: Patents & Royalties. Gottschalk:TESSA Therapeutics: Other: research collaboration; Inmatics and Tidal: Membership on an entity's Board of Directors or advisory committees; Merck and ViraCyte: Consultancy; Patents and patent applications in the fields of T-cell & Gene therapy for cancer: Patents & Royalties. Velasquez:St. Jude: Patents & Royalties; Rally! Foundation: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Clinical Development of a Non-Gene-Edited Allogeneic Bcma-Targeting CAR T-Cell Product in Relapsed or Refractory Multiple Myeloma

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 27-28
Author(s):  
A. Samer Al-Homsi ◽  
Sebastien Anguille ◽  
Jason Brayer ◽  
Dries Deeren ◽  
Nathalie Meuleman ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Lines ◽  
Gene Editing ◽  
Cell Product ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Background Autologous CAR T-cell therapy targeting the B-cell maturation antigen (BCMA) has shown impressive objective response rates in patients with advanced multiple myeloma (MM). Clinical grade manufacturing of autologous CAR T-cells has limitations including vein-to-vein delivery time delay and potentially sub-optimal immunological capability of T-cells isolated from patients with advanced disease. Allogeneic CAR T-cell products, whereby cells from healthy third-party donors are used to generate an "off-the-shelf" CAR T-cell product, have the potential to overcome some of these issues. To circumvent the primary potential risk of graft-versus-host disease (GvHD) associated with the use of allogeneic T-cells, abrogation of the T-cell receptor (TCR) expression in the CAR T-cells, via gene editing, is being actively pursued. To avoid the potential safety risks and manufacturing challenges associated with gene editing, the allogeneic CYAD-211 CAR T-cell product exploits short hairpin RNA (shRNA) interference technology to down-regulate TCR expression thus avoiding the risk of life-threatening GvHD. Aim The aim is to generate a BCMA-specific allogeneic CAR T-cell product using a non-gene editing approach and study its activity both in vitro and in vivo. CYAD-211 combines a BCMA-specific CAR with a single optimized shRNA targeting the TCR CD3ζ subunit. Downregulation of CD3ζ impairs the TCR expression on the surface of the donor T-cells, preventing their reactivity with the normal host tissue cells and potential GvHD induction. Maintaining all the elements required for the therapy within a single vector (all-in-one vector) provides some significant manufacturing advantages, as a solitary selection step will isolate cells expressing all the desired traits. Results CYAD-211 cells produce high amounts of interferon-gamma (IFN-γ) during in vitro co-cultures with various BCMA-expressing MM cell lines (i.e., RPMI-8226, OPM-2, U266, and KMS-11). Cytotoxicity experiments confirmed that CYAD-211 efficiently kills MM cell lines in a BCMA-specific manner. The anti-tumor efficacy of CYAD-211 was further confirmed in vivo, in xenograft MM models using the RPMI-8226 and KMS-11 cell lines. Preclinical data also showed no demonstrable evidence of GvHD when CYAD-211 was infused in NSG mice confirming efficient inhibition of TCR-induced activation. Following FDA acceptance of the IND application, IMMUNICY-1, a first-in-human, open-label dose-escalation phase I clinical study evaluating the safety and clinical activity of CYAD-211 for the treatment of relapsed or refractory MM patients to at least two prior MM treatment regimens, is scheduled to begin recruitment. IMMUNICY-1 will evaluate three dose-levels of CYAD-211 (3x107, 1x108 and 3x108 cells/infusion) administered as a single infusion after a non-myeloablative conditioning (cyclophosphamide 300 mg/m²/day and fludarabine 30 mg/m²/day, daily for 3 days) according to a classical Fibonacci 3+3 design. Description of the study design and preliminary safety and clinical data from the first cohort will be presented at ASH 2020. Conclusion CYAD-211 is the first generation of non-gene edited allogeneic CAR T-cell product based on shRNA technology. The IMMUNICY-1 clinical study seeks to provide proof of principle that single shRNA-mediated knockdown can generate fully functional allogeneic CAR T-cells in humans without GvHD-inducing potential. We anticipate that subsequent generations of this technology will incorporate multiple shRNA hairpins within a single vector system. This will enable the production of allogeneic CAR T-cells in which multiple genes of interest are modulated simultaneously thereby providing a platform approach that can underpin the future of this therapeutic modality. Figure 1 Disclosures Al-Homsi: Celyad: Membership on an entity's Board of Directors or advisory committees. Brayer:Janssen: Consultancy; Bristol-Myers Squibb, WindMIL Therapeutics: Research Funding; Bristol-Myers Squibb, Janssen, Amgen: Speakers Bureau. Nishihori:Novartis: Other: Research support to institution; Karyopharm: Other: Research support to institution. Sotiropoulou:Celyad Oncology: Current Employment. Twyffels:Celyad Oncology: Current Employment. Bolsee:Celyad Oncology: Current Employment. Braun:Celyad Oncology: Current Employment. Lonez:Celyad Oncology: Current Employment. Gilham:Celyad Oncology: Current Employment. Flament:Celyad Oncology: Current Employment. Lehmann:Celyad Oncology: Current Employment.

scholarly journals ATRA Augments BCMA Expression on Myeloma Cells and Enhances Recognition By BCMA-CAR T-Cells

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 13-14
Author(s):  
Estefania Garcia-Guerrero ◽  
Luis Gerardo Rodríguez-Lobato ◽  
Sophia Danhof ◽  
Belén Sierro-Martínez ◽  
Ralph Goetz ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Lines ◽  
Research Funding ◽  
Xenograft Model ◽  
Atra Treatment ◽  
Car T Cells ◽  
Secretase Inhibitor ◽  
Car T ◽  
Epigenetic Modulation

Background: B cell maturation antigen (BCMA) is a B-lineage antigen that is retained on malignant plasma cells in multiple myeloma (MM), and is under investigation as a target antigen for humoral and cellular immunotherapy. Targeting BCMA with chimeric antigen receptor (CAR) T-cells, T-cell engaging antibodies and antibody-drug conjugates has resulted in high rates of clinical responses however, the depth and durability of these responses is still not satisfactory and most patients ultimately relapse. This has been attributed at least in part to low or non-uniform BCMA expression on MM cells, as well as MM cell escape after BCMA down-regulation or even loss. Here, we show that epigenetic modulation with all-trans retinoic acid (ATRA) augments BCMA expression at the gene (and protein) level and leads to enhanced BCMA molecule density on the surface of MM cells that translates into increased anti-MM potency of BCMA CAR T-cells. Methods: Primary MM cells and myeloma cell lines were treated with titrated doses of ATRA (25, 50, 100 nM), alone and in combination with the g-secretase inhibitor crenigacestat (10 nM). BCMA expression was analyzed by flow cytometry, RT-qPCR and direct stochastic optical reconstruction microscopy (dSTORM). BCMA CAR T-cells were derived from healthy donors and MM patients (n&gt;6) and their anti-MM function analyzed in vitro and in the NSG/MM.1S murine xenograft model in vivo. Results: By RT-qPCR, we observed a 1.8-fold (MM.1S) and 2.1-fold (OPM-2) increase in BCMA gene expression after treatment with 50 nM ATRA for 72 hours. By flow-cytometry, we confirmed increased BCMA protein expression, with 1.9-fold (MM.1S and OPM-2) increase in mean fluorescence intensity relative to isotype control staining. Super-resolution dSTORM microscopy on MM.1S cells confirmed the increase in BCMA protein expression and showed a homogenous distribution pattern of BCMA molecules across the cell surface without an increase in cluster formation. These data were confirmed with primary MM cells from patients with newly diagnosed (n=7) and relapsed/refractory (n=11) MM. The increase in MFI for BCMA expression on primary MM cells after ATRA treatment was 1.2-fold - 2.2-fold (mean: 1.6-fold; p=.01 at 50 nM ATRA). By ELISA, we did not detect increased levels of soluble BCMA protein in supernatant of MM.1S cells after ATRA treatment. Accordingly, we found superior cytolytic activity, cytokine secretion and proliferation of CD8+ and CD4+BCMA CAR T-cells in response to ATRA-treated vs. non-treated primary MM cells and MM cell lines. In the NSG/MM.1S xenograft model, we confirmed increased BCMA expression on MM.1S after systemic treatment with ATRA, and superior anti-MM activity after adoptive transfer of BCMA CAR T-cells. Further, we confirmed that epigenetic modulation of BCMA-expression with ATRA works synergistically with g-secretase inhibitor treatment that has recently been shown to prevent cleavage of BCMA molecules from the surface of MM cells (Pont Blood 2019). Combination treatment with ATRA and the g-secretase inhibitor crenigacestat led to higher BCMA density on primary MM cells (and cell lines) than each single-agent treatment alone, resulting in maximum reactivity of by BCMA CAR T-cells in vitro and in vivo. Conclusions: Taken together, the data show that BCMA expression on MM cells can be increased by epigenetic modulation with ATRA. After ATRA treatment, MM cells have increased susceptibility to BCMA CAR T-cell treatment in pre-clinical models vitro and in vivo, that can be increased even further by combination treatment of ATRA and g-secretase inhibitors. These data suggest the potential to improve responses (depth and durability) of immunotherapies directed against BCMA. Disclosures Einsele: Takeda: Consultancy, Honoraria, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau; GlaxoSmithKline: Honoraria, Research Funding, Speakers Bureau.

scholarly journals A New Promising Third Generation CAR-CD30 T-Cell Therapy for CD30+ Lymphoma

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2069-2069
Author(s):  
Biagio De Angelis ◽  
Marika Guercio ◽  
Domenico Orlando ◽  
Stefano Di Cecca ◽  
Matilde Sinibaldi ◽  
...  
Keyword(s):  
T Cells ◽  
Board Of Directors ◽  
Cell Lines ◽  
Short Term ◽  
Advisory Committees ◽  
Car T Cells ◽  
Car T

Prognosis of a significant proportion of patients with chemotherapy-refractory or multiply-relapsed CD30+ Non-Hodgkin's Lymphoma (NHL) or Hodgkin lymphoma (HL) still remain poor. Targeting CD30 with monoclonal antibodies in HL and anaplastic large cell lymphoma was shown to induce remarkable clinical activity; however, occurrence of adverse events (mainly neuropathy) may result into treatment discontinuation in many patients. Immunotherapeutic approaches targeting CD30 by chimeric antigen receptor (CAR) has been demonstrated to be of value in two independent clinical trials, although clinical benefit was sub-optimal. We designed a new CAR construct characterized by an anti-CD30 single-chain variable-fragment cassette (AC10), linked to CD3ζ by the signaling domains of two costimulatory molecules, namely either CD28.4-1BB or CD28.OX40. The inducible Caspase-9 (iCasp9) safety switch was included in both constructs with the goal of promptly controlling undue toxicity. As a selectable marker, we added in frame the CD34 antigen. The in vitro anti-tumor efficacy was evaluated by using either the NHL cell line: Karpas299, or the HL cell lines: L428, in both short-term cytotoxic assay (51Cr release assays) and long-term co-cultures for 6 days. Supernatant from co-culture experiments was analyzed by Elisa. We assessed the antitumor effect of CAR.CD30 T cells in a in vivo NSG mouse model engrafted i.v. with lymphoma FF-luciferase cell lines Karpas299 or L428, and monitored tumor growth by IVIS Imaging system. For tumor re-challenging, mice of the NHL model surviving until day +140, were i.v. infused with 0.2x106 Karpas299 cells, and subsequently followed for additional 110 days. Persistence of CAR.CD30 T cells was evaluated, together with a deep characterization of memory profile of T cells. Independently from the costimulatory domains CD28.OX40 or CD28.4-1BB, the generated retroviral vectors showed similar transduction efficiency of T cells (86.5±5.1% and 79.3±5.3%, respectively). Nevertheless, CD28.OX40 costimulatory domains was associated with more stable expression of the CAR over time, during extensive in vitro culture (84.72±5.30% vs 63.98±11.51% CD28.4-1BB CAR T cells at 30 days after transduction; p=0.002). For both CAR constructs, we did not observe any significant difference in the suicide gene iCasp9 activity, both in vitro and in vivo. In short-term cytotoxic assay, both CAR.CD30 T cells significantly and specifically lysed CD30+ NHL and HL tumor cell lines. In long-term co-culture, CD28.OX40 showed a superior anti-lymphoma in vitro activity as compared to CD28.41BB T cells, when challenged at very high tumor/effector ratio (8:1) (for Karpas 299; p=0.03). Moreover, the antigen stimulation was associated to higher levels of Th1 cytokine production, with CD28.OX40 T cells secreting a significantly higher amount of IFNγ, IL2 and TNFα as compared to CD28.41BB T cells (p= 0.040; p=0.008; p=0.02; respectively). Bioluminescence in HL (L428) tumor-bearing mice, treated with NT T cells, rapidly increased up to 5 log in less than 50 days and mice either died or were sacrificed due to morbidity. The best outcome was observed in mice treated with CD28.OX40, as three out of five mice were still alive at the experimental end-point of day+165, as compared with mice treated with CD28.4-1BB (60% vs 0%, p=0.0021). In NHL (Karpas 299) mouse models, CD28.OX40 had an extensive anti-tumor control superior to that of CD28.41BB T cells, leading to a significant reduction of tumor bioluminescence at day 45 (3.32x10 vs 2.29x10, p=0.04). The median survival of mice treated with NT and CD28.4-1BB CAR T cells was 45.5 and 58 days respectively, but undetermined for mice treated with CD28.OX40 CAR T cells (p=0.0002). After 140 days, cured mice were re-challenged with Karpas 299; mice were followed for other 100 days. Bioluminescence analysis showed rapid progression of the tumor in the control mice cohort, as well as in CD28.4-1BB treated mice. In contrast, in CD28.OX40 treated mice, at day+240 days, 4 out of 6 mice were tumor-free, resulting into a statistically significant survival benefit (p=0.0014). Only in mice treated with 28.OX40 T cells, we observed a long-lasting persistence of circulating CAR-T cells up to day +221. In summary, we have developed a novel CAR.CD30 construct displaying features that make it a particularly suitable candidate for a clinical trial in patients suffering from CD30+ tumors. Disclosures Merli: Novartis: Honoraria; Sobi: Consultancy; Amgen: Honoraria; Bellicum: Consultancy. Locatelli:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bellicum: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BluebirdBio: Consultancy; Miltenyi: Honoraria; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

scholarly journals PL2.1 Exploiting the DNAM-1 system for chimeric antigen receptor (CAR) T cell therapy of glioblastoma

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii2-iii2
Author(s):  
T Weiss ◽  
H Meister ◽  
M Weller ◽  
C Sentman ◽  
P Roth
Keyword(s):  
T Cells ◽  
Cell Lines ◽  
Glioma Cell ◽  
Knock Out ◽  
Car T Cells ◽  
Car T ◽  
Glioma Cell Lines ◽  
Mouse Glioma

Abstract BACKGROUND Cancer immunotherapy with genetically engineered T cells that express a chimeric antigen receptor (CAR) has led to impressive responses in extracranial malignancies and is also explored against glioblastoma. However, CAR T cell strategies that are currently being explored against glioblastoma target single tumor antigens, which are non-homogeneously expressed and are prone to antigen escape. Furthermore, the immunosuppressive brain tumor microenvironment hampers anti-tumor efficacy. METHODS By immunohistochemistry and flow cytometry, we investigated the expression of CD155 and CD112, which are ligands to the activating immune cell receptor DNAX accessory molecule-1 (DNAM-1), in human and mouse glioma cell lines as well as in human glioblastoma samples. To understand their functional role, we generated CD155 or CD112 knock-out glioma cell lines using CRISPR/Cas9 and studied proliferation, sensitivity to irradiation or temozolomide as well as migration. To exploit the promiscuous binding features of DNAM-1, we generated different first or second-generation CAR T cells that use DNAM-1 as a tumor-binding domain. Subsequently, we investigated their anti-tumor activity in vitro in co-culture assays and in vivo in syngeneic orthotopic murine glioma models. RESULTS CD155 and CD112 are homogenously expressed in human and mouse glioma cell lines and human glioblastoma tissues. Knock-out of these ligands affected the migration of tumor cells, but did not affect proliferation or sensitivity to irradition or temozolomide. DNAM-1-based CAR T cells demonstrated high cytolytic activity and effector cytokine secretion in vitro. In vivo, DNAM-1 based CAR T cells reached to the tumor site in the brain upon intravenous administration, prolonged survival of orthotopic glioma-bearing mice and led to a durable anti-tumor response in a fraction of mice. The treatment was tolerated without toxicities. CONCLUSION We elucidated the tumor-intrinisic role of CD155 and CD112 and provide the first systematical preclincal assessment of DNAM-1 CAR T cells against glioma. These findings provide a rationale to test this immunotherapeutic strategy also in human glioma patients.

scholarly journals Anti-Human CD117 CAR T-Cells Efficiently Eliminate Hematopoietic Stem and CD117-Positive AML Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4063-4063 ◽  
Author(s):  
Renier Myburgh ◽  
Jonathan Kiefer ◽  
Norman F Russkamp ◽  
Alexander Simonis ◽  
Surema Pfister ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cell Lines ◽  
Surface Expression ◽  
Hematopoietic Stem ◽  
Car T Cells ◽  
Car T

Abstract Introduction: Acute Myeloid Leukemia (AML) is a clonal disease of the hematopoietic system that originates from immature hematopoietic stem and progenitor cells (HSPC). Because some AML-initiating cells are comparatively resistant to conventional cytotoxic agents, disease relapses are common with current treatment approaches. As an alternative, immunological eradication of leukemic cells by adoptively transferred chimeric-antigen receptor T-cells (CAR T-cells) might be considerably more efficient. To date, however, the search for AML-specific surface antigens has remained largely elusive. To circumvent this problem, we propose to target the stem cell antigen c-Kit (CD117) that is expressed by physiological HSPC as wells as by leukemic blasts in >90% of AML patients. For translation into a clinical setting, CAR T cell treatment must then be followed by depletion of CAR T-cells as well subsequent healthy/allogeneic HSC transplantation. Methods: A lentiviral vector was generated which incorporates the CAR (scFv linked to intracellular CD3ζ and 4-1BB signaling domains via stalk and transmembrane regions derived from CD8), followed by a T2A ribosomal skip sequence and RQR8 as selection marker and depletion gene (surface expression of CD34 and CD20 epitopes). The scFv was extracted from a previously published bivalent anti-CD117 antibody (clone 79D) that was derived from an artificial human phage library (Reshetnyak et al., PNAS, 2013). 79D exhibits high binding affinity to an epitope in the membrane-proximal domain of human CD117. Human CD117 was cloned in human CD117 negative HL-60 AML cells and cell lines with stable expression of CD117 at various levels were derived from these. Results: T-cells were isolated from healthy donors or AML patients in complete remission and both healthy donor and AML pateint derived T-cells exhibited sustained growth after activation with recombinant human IL-2 and CD3/CD28 beads. Lentiviral transduction yielded consistently high transduction rates, ranging from 55 - 75% as determined by staining for RQR8 and the scFv. In co-culture assays, CAR T-cells eliminated more than 90% of CD117high leukemia cell lines within 24 hours at effector-to target ratios (E:T) of 4:1 and 1:1 and more than 50% at E:T of 1:4. CAR-mediated cytotoxicity correlated with levels of CD117 surface expression as the elimination of CD117low target cells was less efficient compared to CD117high and CD117intermediate cells. In long-term cytotoxicity assays (45d), only CD117low cells were able to escape CAR-mediated killing. In the setting of primary cells, anti-CD117 CAR T-cells effectively depleted >90% of lin-CD117+CD34+CD38+ and >70% of lin-CD117+CD34+CD38- cells from healthy bone marrow in vitro within 48 hours. Similarly, >70% of patient derived leukemic blasts were eliminated by autologous anti-CD117 CAR T-cells within 48 hours (1:1 ratio of CAR T cells:blasts). In a long-term assay, no outgrowth of leukemic blasts was observed in the presence of autologous CAR T-cells over 3 weeks. To determine effectivity of CAR T-cells in vivo, humanized mice (NSG & MTRG-SKI) were engrafted with umbilical cord blood derived CD34+ cells. A single injection of 2x106 anti-CD117 CAR T-cells resulted in >90% depletion of CD117+ cells in the bone marrow within 6 days. Finally, humanized mice transplanted with bone marrow from AML patients expressing CD117 were treated with patient-derived autologous CAR T-cells. At 6 weeks after injection of CAR T-cells, >98% of hu-CD45 CD117+ cells were depleted in the bone marrow while control human T-cell treated mice showed full-blown CD117 positive AML. Conclusions: We provide proof of concept for the generation of highly-potent CAR T-cells re-directed against CD117 from healthy human donors and AML patients. Anti-CD117 CAR T-cells exhibit high cytotoxic activity against CD117+ cell lines as well as primary healthy HSPC and patient AML cells in vitro and in vivo in murine xenograft models. Strategies for the complete elimination of CAR T-cells (immunologic or small molecule based) are required before translation of this approach to the clinical setting. Disclosures Neri: Philochem AG: Equity Ownership.

PL03.3.A Development and characterization of CD317-specific CAR T cells as an innovative immunotherapeutic strategy against glioblastoma

2021 ◽  
Vol 23 (Supplement_2) ◽  
pp. ii2-ii2
Author(s):  
L Hänsch ◽  
M Peipp ◽  
R Myburgh ◽  
M Silginer ◽  
T Weiss ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Lines ◽  
Glioma Cells ◽  
Target Antigen ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Abstract BACKGROUND Due to the limited success of existing therapies for gliomas, innovative therapeutic options are urgently needed. Chimeric antigen receptor (CAR) T cell therapy has been successful in patients with hematological malignancies. However, using this treatment against solid tumors such as glioblastomas is more challenging. Here, we generated CAR T cells targeting the transmembrane protein CD317 (BST-2, HM1.24) which is overexpressed in glioma cells and may therefore serve as a novel target antigen for CAR T cell-based immunotherapy. MATERIAL AND METHODS CAR T cells targeting CD317 were generated by lentiviral transduction of human T cells from healthy donors. The anti-glioma activity of CD317-CAR T cells was determined in lysis assays using different glioma target cell lines with varying CD317 expression levels. The efficiency of CD317-CAR T cells to control tumor growth in vivo was evaluated in clinically relevant orthotopic xenograft glioma mouse models. RESULTS We created a second-generation CAR construct targeting CD317 and observed strong anti-glioma activity of CD317-CAR T cells in vitro. Glioma cells with a CRISPR/Cas9-mediated CD317 knockout were resistant to CD317-specific CAR T cells, demonstrating their target antigen-specificity. Since CD317 is also expressed by T cells, transduction with a CD317-directed CAR resulted in fratricide of the transduced T cells. Silencing of CD317 in CAR T cells by integrating a specific shRNA into the CAR vector significantly increased the viability, proliferation and cytotoxic function of the CAR T cells. Importantly, intratumoral treatment with CD317-CAR T cells prolonged the survival and cured a significant fraction of glioma-bearing nude mice. CONCLUSION We demonstrate strong CD317-specific anti-tumor activity of CD317-CAR T cells against various glioma cell lines in vitro and in xenograft glioma models in vivo. These data lay a scientific basis for the subsequent evaluation of this therapeutic strategy in clinical neuro-oncology.

scholarly journals A BCMAxCD3 bispecific T cell–engaging antibody demonstrates robust antitumor efficacy similar to that of anti-BCMA CAR T cells

2021 ◽  
Vol 5 (5) ◽  
pp. 1291-1304
Author(s):  
David J. DiLillo ◽  
Kara Olson ◽  
Katja Mohrs ◽  
Thomas Craig Meagher ◽  
Kevin Bray ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Lines ◽  
Antitumor Efficacy ◽  
Therapeutic Effects ◽  
Tumor Site ◽  
Car T Cells ◽  
Car T

Abstract CD3-engaging bispecific antibodies (bsAbs) and chimeric antigen receptor (CAR) T cells are potent therapeutic approaches for redirecting patient T cells to recognize and kill tumors. Here we describe a fully human bsAb (REGN5458) that binds to B-cell maturation antigen (BCMA) and CD3, and compare its antitumor activities vs those of anti-BCMA CAR T cells to identify differences in efficacy and mechanism of action. In vitro, BCMAxCD3 bsAb efficiently induced polyclonal T-cell killing of primary human plasma cells and multiple myeloma (MM) cell lines expressing a range of BCMA cell surface densities. In vivo, BCMAxCD3 bsAb suppressed the growth of human MM tumors in murine xenogeneic models and showed potent combinatorial efficacy with programmed cell death protein 1 blockade. BCMAxCD3 bsAb administration to cynomolgus monkeys was well tolerated, resulting in the depletion of BCMA+ cells and mild inflammatory responses characterized by transient increases in C-reactive protein and serum cytokines. The antitumor efficacy of BCMAxCD3 bsAb was compared with BCMA-specific CAR T cells containing a BCMA-binding single-chain variable fragment derived from REGN5458. Both BCMAxCD3 bsAb and anti-BCMA CAR T cells showed similar targeted cytotoxicity of MM cell lines and primary MM cells in vitro. In head-to-head in vivo studies, BCMAxCD3 bsAb rapidly cleared established systemic MM tumors, whereas CAR T cells cleared tumors with slower kinetics. Thus, using the same BCMA-binding domain, these results suggest that BCMAxCD3 bsAb rapidly exerts its therapeutic effects by engaging T cells already in place at the tumor site, whereas anti-BCMA CAR T cells require time to traffic to the tumor site, activate, and numerically expand before exerting antitumor effects.

scholarly journals Chimeric Antigen Receptor T-Cells for the Treatment of Gamma-Delta T-Cell Malignancies

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3338-3338
Author(s):  
Paul Maciocia ◽  
Patrycja Wawrzyniecka ◽  
Leo Kassimatis ◽  
Martin Pule
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Lines ◽  
Chimeric Antigen Receptor ◽  
Antigen Receptor ◽  
Gamma Delta ◽  
Car T Cells ◽  
Car T ◽  
Gamma Delta T Cell

Abstract Introduction Cancers derived from the malignant transformation of gamma delta T-cells are rare but carry very poor prognosis. Hepatosplenic T-cell lymphoma is a highly aggressive condition characterised by hepatosplenic and bone marrow involvement. It has among the worst outcomes of all lymphoma subtypes, with a median survival of only 6-8 months. 95% of cases express the gamma delta T-cell receptor (GDTCR), which is also expressed on a proportion of cases of T-ALL. Treatment for these cancers is based on cytotoxic chemotherapy, with no tumour-specific therapies including immunotherapy available. We have developed a novel chimeric antigen receptor targeting GDTCR and here demonstrate specific in vitro and in vivo efficacy against gamma delta T-cell malignancies. Results We cloned anti-GDTCR antibody as a single chain variable fragment (ScFv), and confirmed specific binding to GDTCR-positive T-cell cell lines and primary GD cells. Next, we cloned anti-GDTCR ScFv into a 2ndgeneration chimeric antigen receptor (CAR) format, including a spacer derived from CD8-stalk, CD28 transmembrane domain and 41BB-zeta endodomain. This construct was stably introduced to primary alpha-beta T-cells by retroviral transduction and surface expression was confirmed by flow cytometry. We established 48-hour co-cultures of anti-GDTCR CAR T-cells or control anti-CD19 CAR T-cells with T-cell lines positive (Loucy, BE13, MOLT-13) or negative for surface GDTCR (Jurkat, SupT1-CD19). While control anti-CD19 CAR killed only SupT1-CD19 cells, specific cytotoxicity was seen by anti-GDTCR CAR T-cells only against GDTCR-positive cell lines. In addition, anti-GDTCR CAR T-cells demonstrated specific secretion of cytokines including interferon gamma and IL-2, and robust antigen-specific proliferation only in co-culture with GDTCR-positive cells. Expression of exhaustion, activation and differentiation markers in long term co-cultures with target cells was similar to that seen with control anti-CD19 CAR. To assess the in vivo potency of anti-GDTCR CAR T-cells, we established a murine model of disseminated GDTCR-positive leukaemia. NSG mice were intravenously injected with 4x10^6 Loucy cells, engineered to stably express Firefly luciferase. Tumour engraftment in bone marrow was confirmed at D7 following injection, and mice were treated with 0.8x10^6 anti-GDTCR or control anti-CD19 CAR T-cells. Disease burden was monitored by bioluminescence imaging. Mice receiving anti-GDTCR CAR demonstrated substantial reduction of tumour burden, increased expansion of CAR T-cells and prolonged survival compared to control-CAR treated animals. Conclusions We have developed a novel chimeric antigen receptor T-cell treatment for gamma-delta TCR-positive malignancies, including hepatosplenic T-cell lymphoma and some cases of T-ALL. Our approach is, to our knowledge, the first immunotherapeutic strategy proposed for these conditions. Given the restricted expression of GD-TCR on a small subset (0.5-5%) of peripheral T-cells and the absence of a clear human phenotype associated with GD T-cell deficiency, we suggest that this therapy may be well tolerated. Given the very poor prognosis and lack of effective therapies for GD-TCR-positive malignancies, as well as the considerable efficacy of CAR T-cell therapy in analogous B-cell disorders, our approach could bring much needed benefit to patients suffering these conditions. Disclosures Maciocia: Autolus: Equity Ownership, Patents & Royalties: UCLB. Pule:UCLB: Patents & Royalties; Autolus: Employment, Equity Ownership.

scholarly journals Expression of MyD88/CD40 Drives In Vivo Activation and Proliferation of Chimeric Antigen Receptor-Modified T Cells That Can be Effectively Regulated By Inducible Caspase-9

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 851-851
Author(s):  
Aaron Foster ◽  
Peter Chang ◽  
Pei-Yi Lin ◽  
Jeannette Crisostomo ◽  
Aruna Mahendravada ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cell ◽  
Cell Lines ◽  
Tumor Control ◽  
Tumor Cell Lines ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Abstract Introduction: Efficacy of chimeric antigen receptor (CAR)-modified T cells is dependent on their in vivo survival and expansion following infusion. The addition of accessory molecules (e.g., costimulatory and cytokine genes) may improve CAR-T proliferation and potency, but may also increase toxicity of these next generation CAR-T cell therapies, suggesting that the incorporation of a built in "safety switch" would balance safety and efficacy in a single, controllable therapy. Here, we demonstrate that cytosolic coexpression of a MyD88/CD40-derived fusion protein dramatically enhances CAR-T activation, cytokine production, and proliferation in vivo, resulting in improved antitumor efficacy. Importantly, CAR-T cell numbers, elevated cytokine levels, and observed CAR-T-related toxicity could be controlled by titratable rimiducid administration to reduce or eliminate CAR-T cells by activating the inducible caspase-9 (iC9) suicide gene. Methods: Human T cells were activated with anti-CD3/CD28 and transduced with retrovirus encoding, iC9, a first generation CAR (with CD3ζ) targeting CD19, Her2 or PSCA, and a detached, fusion protein comprising signaling domains from MyD88 and CD40 (MC). For comparison, additional CARs were constructed without MC, with MyD88 or CD40 elements only, or with conventional CARs coexpressing CD28 within the CAR molecule (CAR.28.ζ). Transduced T cells were assessed in vitro for cytotoxicity, cytokine production and proliferation against tumor cell lines (CD19+: Daudi, Raji; Her2+: SK-BR-3; PSCA+: Capan-1, HPAC). In vivo antitumor efficacy of CAR-modified T cells was assessed using immunodeficient NSG mice engrafted with antigen-matched tumor cell lines (5x105 Raji, i.v.; 1x106 SK-BR-3, s.c; 2x106 HPAC, s.c.) followed by i.t. or i.v. injection of variable doses of T cells. Reduction or elimination of CAR-T cells was performed by i.p. injection of rimiducid (0 - 5 mg/kg). Tumor cell lines expressing luciferase or T cells co-transduced with luciferase-encoding vectors were used for bioluminescence imaging (BLI) to measure tumor growth or T cell expansion/elimination, respectively. Serum cytokine levels were assessed by blood draws and CAR-T cell frequency was measured by flow cytometry. Results: All CAR constructs were stably expressed in T cells (30-90%). CAR vectors coexpressing MC induced high IL-2 levels in vitro when exposed to target antigen+ tumor cells (CD19 = 4246 ± 52, Her2 = 2613 ± 1298, and PSCA = 3263 ± 1393 pg/ml per 1x105 T cells over 48 hrs) and corresponded to improved CAR-T cell proliferation and tumor elimination compared to control vectors. In NSG mice, MC costimulation resulted in >2,000-fold expansion of CD19-targeted CAR-T cells and complete tumor control for >100 days in 100% of mice engrafted with CD19+ Raji cells (p = 0.0002) following injection of 5x106 CAR-T cells, followed on day 7 with a single i.p. dose of rimiducid (5 mg/kg) to control toxicity. MC-enabled CAR-T cells were eliminated or partially reduced by rimiducid titrations, which corresponded to decreased cytokine (IL-6, IFN-γ, TNF-α) levels and restoration of health in animals showing signs of toxicity (e.g., ≥15% weight loss). For solid tumors, Her2-targeted, MC-enabled CAR-T cells showed a 150-fold in vivo expansion and compared favorably to first (Her2.ζ; p = 0.01) and second generation (Her2.28.ζ; p = 0.01) CARs, causing 100% elimination of SK-BR-3 tumors and enhanced survival for >60 days following i.t. injection (p = 0.0015). PSCA-targeted CARs expressing MC also drove complete and durable (>42 days) elimination of large (200 mm3) HPAC tumors in 100% of mice, after a single i.v. injection of 1x107 CAR-T cells followed on day 14 with a single 5 mg/kg i.p. rimiducid dose to reverse toxicity. Summary: Coexpression of MC, and the cell therapy safety switch "CaspaCIDe", in combination with a first generation CAR, together comprising the novel "CIDeCAR" platform technology, dramatically increases efficacy against a number of tumor targets by enhancing T cell engraftment and proliferation following infusion, while incorporating an effective, built-in safety mechanism. In three distinct tumor models, rimiducid administration promptly eliminated signs and symptoms of CAR toxicity without subsequent loss of tumor control. CIDeCAR technology may allow the development of safer and more effective CAR-T cell therapies for a range of difficult-to-treat liquid and solid tumors. Disclosures Foster: Bellicum Pharmaceuticals: Employment. Chang:Bellicum Pharmaceuticals: Employment. Lin:Bellicum Pharmaceuticals: Employment. Crisostomo:Bellicum Pharmaceuticals: Employment. Mahendravada:Bellicum Pharmaceuticals: Employment. Lu:Bellicum Pharmaceuticals: Employment. Khalil:Bellicum Pharmaceuticals: Employment. Saha:Bellicum Pharmaceuticals: Employment. Shaw:Bellicum Pharmaceuticals: Employment. Morschl:Bellicum Pharmaceuticals: Employment. Slawin:Bellicum Pharmaceuticals: Employment, Equity Ownership. Spencer:Bellicum Pharmaceuticals: Employment, Equity Ownership.

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