scholarly journals Senescent/Exhausted Phenotype of CAR T Cells and Induction of Immunoregulatory Environment Correlate with Reduced Response to CAR T Cell Therapy in Relapsed/Refractory B Cell Malignancies

2020 ◽  
Vol 26 (3) ◽  
pp. S314-S315
Author(s):  
Katia Beider ◽  
Michal Besser ◽  
Jacob Schachter ◽  
Elad Jacoby ◽  
Avichai Shimoni ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
B Cell ◽  
B Cell Malignancies ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

scholarly journals Iomab with Adoptive Cellular Therapy (Iomab-ACT): A Pilot Study of 131-I Apamistamab Followed By CD19-Targeted CAR T-Cell Therapy for Patients with Relapsed or Refractory B-Cell Acute Lymphoblastic Leukemia or Diffuse Large B-Cell Lymphoma

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4810-4810
Author(s):  
Mark B. Geyer ◽  
Briana Cadzin ◽  
Elizabeth Halton ◽  
Peter Kane ◽  
Brigitte Senechal ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
B Cell ◽  
Research Funding ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Abstract Background: Autologous CD19-targeted chimeric antigen receptor-modified (CAR) T-cell therapy leads to complete responses (CR) in patients (pts) with (w/) relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL, >80% CR rate) and diffuse large B-cell lymphoma (DLBCL, ~40-55% CR rate). However, following fludarabine/cyclophosphamide (Flu/Cy) conditioning and CAR T-cell therapy w/ a CD28 costimulatory domain (e.g. 19-28z CAR T-cells), rates of grade ≥3 ICANS and grade ≥3 cytokine release syndrome (CRS) in pts w/ R/R DLBCL and morphologic R/R B-ALL exceed 30%. CRS and ICANS are associated w/ considerable morbidity, including increased length of hospitalization, and may be fatal. Host monocytes appear to be the major reservoir of cytokines driving CRS and ICANS post-CAR T-cell therapy (Giavradis et al. and Norelli et al., Nature Medicine, 2018). Circulating monocytic myeloid-derived suppressor cells (MDSCs) may also blunt efficacy of 19-28z CAR T-cells in R/R DLBCL (Jain et al., Blood, 2021). The CD45-targeted antibody radioconjugate (ARC) 131-I apamistamab is being investigated at myeloablative doses as conditioning prior to hematopoietic cell transplantation in pts w/ R/R acute myeloid leukemia. However, even at low doses (4-20 mCi), transient lymphocyte and blast reduction are observed. Preclinical studies in C57BL/6 mice demonstrate low-dose anti CD45 radioimmunotherapy (100 microCi) transiently depletes >90% lymphocytes, including CD4/CD8 T-cells, B-cells, NK cells, and T-regs, as well as splenocytes and MDSCs, w/ negligible effect on bone marrow (BM) hematopoietic stem cells (Dawicki et al., Oncotarget, 2020). We hypothesized a higher, yet nonmyeloablative dose of 131-I apamistamab may achieve more sustained, but reversible depletion of lymphocytes and other CD45 + immune cells, including monocytes thought to drive CRS/ICANS. We additionally hypothesized this approach (vs Flu/Cy) prior to CAR T-cell therapy would promote CAR T-cell expansion while reducing CSF levels of monocyte-derived cytokines (e.g. IL-1, IL-6, and IL-10), thus lowering the risk of severe ICANS (Fig 1A). Study design and methods: We are conducting a single-institution pilot study of 131-I apamistamab in lieu of Flu/Cy prior to 19-28z CAR T-cells in adults w/ R/R BALL or DLBCL (NCT04512716; Iomab-ACT); accrual is ongoing. Pts are eligible for leukapheresis if they are ≥18 years-old w/ R/R DLBCL (de novo or transformed) following ≥2 chemoimmunotherapy regimens w/ ≥1 FDG-avid measurable lesion or B-ALL following ≥1 line of multi-agent chemotherapy (R/R following induction/consolidation; prior 2 nd/3 rd gen TKI required for pts w/ Ph+ ALL) w/ ≥5% BM involvement and/or FDG-avid extramedullary disease, ECOG performance status 0-2, and w/ appropriate organ function. Active or prior CNS disease is not exclusionary. Pts previously treated w/ CD19-targeted CAR T-cell therapy are eligible as long as CD19 expression is retained. See Fig 1B/C: Post-leukapheresis, 19-28z CAR T-cells are manufactured as previously described (Park et al., NEJM, 2018). Bridging therapy is permitted at investigator discretion. Thyroid blocking is started ≥48h pre-ARC. 131-I apamistamab 75 mCi is administered 5-7 days pre-CAR T-cell infusion to achieve total absorbed marrow dose ~200 cGy w/ remaining absorbed dose <25 cGy at time of T-cell infusion. 19-28z CAR T-cells are administered as a single infusion (1x10 6/kg, B-ALL pts; 2x10 6/kg, DLBCL pts). The primary objective is to determine safety/tolerability of 131-I apamistamab 75 mCi given prior to 19-28z CAR T-cells in pts w/ R/R B-ALL/DLBCL. Secondary objectives include determining incidence/severity of ICANS and CRS, anti-tumor efficacy, and 19-28z CAR T-cell expansion/persistence. Key exploratory objectives include describing the cellular microenvironment following ARC and 19-28z CAR T-cell infusion using spectral cytometry, as well as cytokine levels in peripheral blood and CRS. The trial utilizes a 3+3 design in a single cohort. If dose-limiting toxicity (severe infusion-related reactions, treatment-resistant severe CRS/ICANS, persistent regimen-related cytopenias, among others defined in protocol) is seen in 0-1 of the first 3 pts treated, then up to 6 total (up to 3 additional) pts will be treated. We have designed this study to provide preliminary data to support further investigation of CD45-targeted ARCs prior to adoptive cellular therapy. Figure 1 Figure 1. Disclosures Geyer: Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Actinium Pharmaceuticals, Inc: Research Funding; Amgen: Research Funding. Geoghegan: Actinium Pharmaceuticals, Inc: Current Employment. Reddy: Actinium Pharmaceuticals: Current Employment, Current holder of stock options in a privately-held company. Berger: Actinium Pharmaceuticals, Inc: Current Employment. Ludwig: Actinium Pharmaceuticals, Inc: Current Employment. Pandit-Taskar: Bristol Myers Squibb: Research Funding; Bayer: Research Funding; Clarity Pharma: Research Funding; Illumina: Consultancy, Honoraria; ImaginAb: Consultancy, Honoraria, Research Funding; Ymabs: Research Funding; Progenics: Consultancy, Honoraria; Medimmune/Astrazeneca: Consultancy, Honoraria; Actinium Pharmaceuticals, Inc: Consultancy, Honoraria; Janssen: Research Funding; Regeneron: Research Funding. Sauter: Genmab: Consultancy; Celgene: Consultancy, Research Funding; Precision Biosciences: Consultancy; Kite/Gilead: Consultancy; Bristol-Myers Squibb: Research Funding; GSK: Consultancy; Gamida Cell: Consultancy; Novartis: Consultancy; Spectrum Pharmaceuticals: Consultancy; Juno Therapeutics: Consultancy, Research Funding; Sanofi-Genzyme: Consultancy, Research Funding. OffLabel Disclosure: 131-I apamistamab and 19-28z CAR T-cells are investigational agents in treatment of ALL and DLBCL

scholarly journals Case Report: Sirolimus Alleviates Persistent Cytopenia After CD19 CAR-T-Cell Therapy

2021 ◽  
Vol 11 ◽  
Author(s):  
Limin Xing ◽  
Yihao Wang ◽  
Hui Liu ◽  
Shan Gao ◽  
Qing Shao ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
B Cell ◽  
B Cell Lymphoma ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Chimeric antigen receptor T (CAR-T) cells show good efficacy in the treatment of relapsed and refractory B-cell tumors, such as acute B-cell leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL). The main toxicities of CAR-T include cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, cytopenia, and severe infection. It is still very difficult for CAR-T to kill tumor cells to the maximum extent and avoid damaging normal organs. Here, we report a case of DLBCL with persistent grade 4 thrombocytopenia and severe platelet transfusion dependence treated with CD19 CAR-T cells. We used sirolimus to inhibit the sustained activation of CAR-T cells and restore normal bone marrow hematopoiesis and peripheral blood cells. Moreover, sirolimus treatment did not affect the short-term efficacy of CAR-T cells, and DLBCL was in complete remission at the end of follow-up. In conclusion, sirolimus can represent a new strategy for the management of CAR-T cell therapy-related toxicity, including but not limited to hematotoxicity. However, further controlled clinical studies are required to confirm these findings.

scholarly journals Antitumor efficacy of BAFF-R targeting CAR T cells manufactured under clinic-ready conditions

2020 ◽  
Vol 69 (10) ◽  
pp. 2139-2145
Author(s):  
Zhenyuan Dong ◽  
Wesley A. Cheng ◽  
D. Lynne Smith ◽  
Brian Huang ◽  
Tiantian Zhang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
B Cell ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T ◽  
Antigen Loss

Abstract B-cell malignancies can potentially be cured by CD19 chimeric antigen receptor (CAR) T-cell therapy. Although clinical response rates can be up to 93% in acute lymphoblastic leukemia, treatment-related antigen loss and lack of therapeutic persistence contribute to disease relapse. These shortcomings of current CAR T-cell therapy indicate the need for biologically relevant target selection and for improving the efficacy and persistence of the CAR T cells, which we have addressed by developing a novel B-cell activating factor receptor (BAFF-R) CAR T-cell therapy with improved therapeutic persistence. BAFF-R is a B-cell survival receptor and highly expressed in B-cell malignancies. We developed a prototype CAR T cell that efficiently and specifically eliminated BAFF-R expressing human B-cell tumors in several xenogeneic mouse models, including models of CD19 antigen loss. We proceeded with translational development and validation of BAFF-R CAR T cells produced under current good manufacturing practices (cGMP). cGMP-grade BAFF-R CAR T cells underwent in vitro and in vivo validation in established models to confirm that the potency and efficacy of our original research modeling was replicated. Food and Drug Administration required release testing was performed to ensure our BAFF-R CAR T cells meet specifications for new drug products. Completing and exceeding these requirements, the data fully support the initiation of a first-in-human Phase 1 trial for BAFF-R-positive relapsed/refractory (r/r) B-ALL.

scholarly journals Systematically optimized BCMA/CS1 bispecific CAR-T cells robustly control heterogeneous multiple myeloma

2020 ◽  
Author(s):  
Eugenia Zah ◽  
Eunwoo Nam ◽  
Vinya Bhuvan ◽  
Uyen Tran ◽  
Brenda Y. Ji ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
B Cell ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

ABSTRACTChimeric antigen receptor (CAR)-T cell therapy has shown remarkable clinical efficacy against B-cell malignancies but also demonstrated marked vulnerability to antigen escape and tumor relapse. Here, we report the rational design and systematic optimization of bispecific CAR-T cells with robust activity against multiple myeloma (MM), including heterogeneous MM that is resistant to conventional CAR-T cell therapy targeting B-cell maturation antigen (BCMA). We demonstrate that BCMA/CS1 bispecific CAR-T cells exhibit significantly higher CAR expression levels and greater antigen-stimulated proliferation compared to T cells that co-express individual BCMA and CS1 CARs. Compared to single-input BCMA- or CS1-targeting CAR-T cells, BCMA/CS1 bispecific CAR-T cells significantly prolong the survival of animals bearing heterogeneous MM tumors. Combination therapy with anti–PD-1 antibody further accelerates the rate of initial tumor clearance in vivo, but CAR-T cell treatment alone was able to achieve durable tumor-free survival even upon tumor re-challenge. Taken together, the BCMA/CS1 bispecific CAR presents a promising treatment approach to prevent antigen escape in CAR-T cell therapy against MM, and the vertically integrated optimization process can be used to develop robust cell-based therapy against novel disease targets.

scholarly journals P02.01 Predictive impact of the gut microbiota on treatment response to CD19 specific CAR T-cells

2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A20.1-A20
Author(s):  
V Blumenberg ◽  
E Zamir ◽  
S Schmidt ◽  
R Gaiser ◽  
N Cullin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Gut Microbiota ◽  
B Cell ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

BackgroundHigh response rates (RR) have led to the approval of the CD19 specific CAR T-cell products Axicabtagene-Ciloleucel and Tisagenlecleucel for the treatment of refractory/relapsed B-cell precursor ALL (BCP-ALL) and Diffuse Large B-cell lymphoma (DLBCL). However, only a subgroup of patients achieves long-term remission. Additionally, most patients experience adverse effects such as cytokine release syndrome or neurotoxicity. Therefore, we need to better understand mechanisms of relapse and disease progression or toxicity to improve effectiveness of CD19 CAR T-cell therapy. As the gut microbiota plays an important role in modulating T-cell based immunotherapy, we hypothesize, that its signature also impacts clinical outcomes of CAR T-cell therapy.Materials and MethodsWe are currently collecting and 16S rRNA sequencing fecal biospecimen from BCP-ALL and DLBCL patients before, during and after treatment with Axicabtagene-Ciloleucel and Tisagenlecleucel at the University Hospital of the LMU. Microbiota data are integrated into a patient-centered ‘hospitalome’ including onset and type of infection and of immunotoxicity, concomitant anti-infective and immunosuppressive agents as well as response to CAR T-cell therapy.ResultsPreliminary data analysis revealed, that 4–14 days after CAR T-cell infusion the alpha diversity of the gut microbiome of each patient decreases drastically, whereas pre-lymphodepletion gut microbiota has a high diversity. Furthermore, the microbiota composition during the course of treatment changes as seen by beta diversity changes. In more detail, after CAR T-cell infusion, we observed instances of gut microbiota mono-domination with Enterococci or the genus Rikinella.ConclusionsThe gut microbiome of patients being treated with CAR T cells undergoes large and diverse compositional changes. We currently explore how this microbiome heterogeneity relates to the distinct responses and immunotoxicity of patients after CAR T-cell therapy. Hence, this study will enable microbiome-based stratification of patients, in order to predict and improve patient outcome to this personalized T-cell recruiting immunotherapy approach.Disclosure InformationV. Blumenberg: None. E. Zamir: None. S. Schmidt: None. R. Gaiser: None. N. Cullin: None. V. Bücklein: None. C. Schmidt: None. M. von Bergwelt: None. E. Elinav: None. C.K. Stein-Thoeringer: None. M. Subklewe: None.

scholarly journals Targeting CAR T Resistance Due to CD19 Loss with CD79b-Specific CAR T Cells in B-Cell Malignancies

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1662-1662 ◽  
Author(s):  
Fuliang Chu ◽  
Jinsheng Weng ◽  
Shao-Qing Kuang ◽  
Xiaoyun Cheng ◽  
JingJing Cao ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Lymphoma Cell ◽  
B Cell Malignancies ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Abstract Targeting CAR T resistance due to CD19 loss with CD79b-specific CAR T cells in B-cell malignancies Fuliang Chu, JingJing Cao, Jingwei Liu, Xiaoyun Cheng, Swathi Karri, Adithi Reddy, Shao Qing Kuang, Jinsheng Weng, Sattva S. Neelapu Department of Lymphoma and Myeloma, The University of Texas M. D. Anderson Cancer Center. Houston, TX 77030 USA Chimeric antigen receptor (CAR) T cells targeting CD19 are highly effective in B-cell malignancies and two CD19-targteing CAR T-cell therapy products were recently approved by the US FDA for relapsed or refractory B-cell acute lymphoblastic leukemia and/or large B cell lymphoma. In pivotal trials, durable remissions lasting more than 1 year have been observed in ~40-50% of these patients. However, relapse or progression occurs in ~50-60% and a major cause of resistance appears to be due to CD19 antigen loss. Thus, there is an urgent need to develop CAR T-cell therapies against novel targets to further improve outcomes in these patients. CD79b is a pan B-cell linage marker and an important component of the B-cell receptor complex. CD79b is broadly expressed in normal B cells and B-cell malignancies and its expression is usually retained in CD19 negative tumors progressing after CD19-specific CAR T-cell therapy. Here, we report our results with a novel CD79b-specific CAR T cell product in in vitro and in vivo models. We generated five murine monoclonal antibodies against human CD79b by hybridoma technology and demonstrated that they bind specifically to recombinant human CD79b, have high affinity (Kd range of 1.44-18.1 nM), and stain multiple B-cell lymphoma cell lines comparable to the commercial CD79b fluorochrome-labeled antibodies. Next, we cloned the variable regions of the heavy and light chains of the CD79b antibodies, and developed lentiviral constructs for CD79b-specific CARs with CD3z and CD28 costimulatory domains. We demonstrated that the CD79b-CAR lentiviral constructs can be transduced into primary CD4+ and CD8+ T cells from healthy donors to >85% transduction efficiency. We observed that the CD79b-specific CAR T cells but not untransduced T cells had significant cytotoxic activity that was comparable to control CD19-specific CAR T cells against Daudi Burkitt lymphoma and Mino mantle cell lymphoma cell lines. More importantly, CD79b- but not CD19-specific CAR T cells lysed CD19-CD79b+ lymphoma cells. Significant CD107a/b degranulation was also observed in both CD4+ and CD8+ CD79b-specific CAR T cells when they were co-cultured with lymphoma cell lines. Multiplex cytokine analysis of co-culture supernatants revealed predominantly release of IFN-γ. The efficacy of CD79b-specific CAR T cells was also examined in vivo against Mino xenograft models in NSG mice. Luciferase-labeledMino mantle cell lymphoma cell line was injected IV into NSG mice at 2x106 tumor cells/mouse. After 18 days, mice were treated with untransduced primary T cells, CD19-specific CAR, or CD79b-specific CAR T cells via tail vein at 10x106 T cells/mouse. Bioluminescence imaging was used to assess tumor burden. Tumor growth was inhibited and survival was markedly improved in mice treated with CD19- and CD79b-specific CAR T cells but progressive tumor growth was observed in the control group treated with untransduced T cells. Additional studies using CD19-CD79b+ lymphoma cell line xenograft model are ongoing and will be presented at the meeting. In conclusion, these preclinical results indicate that CD79b is a novel target for CAR T-cell therapy and support its evaluation in patients with B-cell malignancies. Importantly, our results suggest that targeting CD79b could be a novel strategy to overcome resistance due to CD19 loss after CD19-specific CAR T-cell therapy. Disclosures No relevant conflicts of interest to declare.

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.

scholarly journals Efficacy and safety of CD22 chimeric antigen receptor (CAR) T cell therapy in patients with B cell malignancies: a protocol for a systematic review and meta-analysis

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Komal Adeel ◽  
Nathan J. Fergusson ◽  
Risa Shorr ◽  
Harold Atkins ◽  
Kevin A. Hay
Keyword(s):  
Systematic Review ◽  
Clinical Trials ◽  
T Cell ◽  
Cell Therapy ◽  
B Cell ◽  
B Cell Malignancies ◽  
T Cell Therapy ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Abstract Background Chimeric antigen receptor (CAR) T cell therapy has had great success in treating patients with relapsed or refractory B cell malignancies, with CD19-targeting therapies now approved in many countries. However, a subset of patients fails to respond or relapse after CD19 CAR T cell therapy, in part due to antigen loss, which has prompted the search for alternative antigen targets. CD22 is another antigen found on the surface of B cells. CARs targeting CD22 alone or in combination with other antigens have been investigated in several pre-clinical and clinical trials. Given the heterogeneity and small size of CAR T cell therapy clinical trials, systematic reviews are needed to evaluate their efficacy and safety. Here, we propose a systematic review of CAR T cell therapies targeting CD22, alone or in combination with other antigen targets, in B cell malignancies. Methods We will perform a systematic search of EMBASE, MEDLINE, Web of Science, Cochrane Register of Controlled Trials, clinicaltrials.gov, and the International Clinical Trials Registry Platform. Ongoing and completed clinical trials will be identified and cataloged. Interventional studies investigating CD22 CAR T cells, including various multi-antigen targeting approaches, in patients with relapsed or refractory B cell malignancies will be eligible for inclusion. Only full-text articles, conference abstracts, letters, and case reports will be considered. Our primary outcome will be a complete response, defined as absence of detectable cancer. Secondary outcomes will include adverse events, overall response, minimal residual disease, and relapse, among others. Quality assessment will be performed using a modified Institute of Health Economics tool designed for interventional single-arm studies. We will report a narrative synthesis of clinical studies, presented in tabular format. If appropriate, a meta-analysis will be performed using a random effects model to synthesize results. Discussion The results of the proposed review will help inform clinicians, patients, and other stakeholders of the risks and benefits of CD22 CAR T cell therapies. It will identify gaps or inconsistencies in outcome reporting and help to guide future clinical trials investigating CAR T cells. Systematic review registration PROSPERO registration number: CRD42020193027

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.

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