scholarly journals Evaluating on-Target Toxicity of Hematopoietic-Targeting Cars Demonstrates Target-Nonspecific Suppression of Marrow Progenitors

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3357-3357 ◽  
Author(s):  
Christopher Tor Sauter ◽  
Christopher Daniel Chien ◽  
Feng Shen ◽  
Sarah K Tasian ◽  
Terry J Fry
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Cytokine Secretion ◽  
Target Antigen ◽  
T Cell Therapy ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Abstract Chimeric Antigen Receptor (CAR)-modified T cells are a class of immunotherapy, most known for producing durable remissions in B-cell malignancies. To date, On-Target/Off-Tumor effects, systemic cytokine syndromes, and neurotoxicity are some types of toxicities encountered in early CAR T cell therapy trials. Initially, we sought to investigate potential toxicity by a novel, FLT3-targeting CAR T cell (FLT3 CAR). As a tumor-associated antigen, FLT3 is expressed on AML, ALL and MLL, as well as non-malignant hematopoietic subsets, warranting evaluation for On-Target toxicity. To examine this, human peripheral mobilized CD34+ stem cells were engrafted into either NSG or NSGSÑan NSG-derived knock-in expressing human interleukin-3, GM-CSF, and stem cell factorÑimmunodeficient murine stains. After establishing hematopoietic xenografts and allowing for reconstitution of circulating human myeloid cells, we treated mice with either FLT3 CARs or mock-transduced T cells derived from a marrow-autologous donor [Figure 1A]. In the presence of FLT3 CARs, we observed loss of circulating mature monocytes compared to mock T cell treated controls. To elucidate if myeloid loss originated from an On-Target toxicity towards a FLT3 expressing progenitor or by some other mechanism, we treated marrow-humanized mice with either FLT3 CAR, a lymphoid restricted CD22-targeting CAR, a mature myeloid restricted CD33-targeting CAR or mock transduced T cells. Two weeks following treatment, we analyzed progenitor subsets including human hematopoietic stem cells (HSC), multipotent progenitors (MPP), common myeloid progenitors (CMP), granulocyte-macrophage progenitors (GMP), maturing marrow granulocytes, common lymphoid progenitors (CLP), and megakaryocyte erythroid progenitors (MEP). Surprisingly, we observed significant marrow loss of CMPs, GMPs, MEPs and CLPs across all mice receiving CARs compared to mice treated with mock transduced T cells alone [Figure 1B]. Absolute numbers of HSCs, MPPs, and total humans cells were equivalent across treatment groups. As the CD19-targeting CAR therapy is most well characterized, we repeated this experiment using CD19 CARs with consistent outcomes [Figure 1C]. Flow cytometric characterization of these progenitor populations confirms that loss still occurs in the absence of target-antigen expression. Taken together, these results suggest that CAR T cell therapy may exert a deleterious effect on specific marrow progenitors through a target antigen-independent mechanism. Furthermore, while a FLT3-CAR On-Target toxicity towards FLT3 expressing progenitors (CLP, GMP, and CMP) can not be fully excluded, an exacerbated progenitor loss compared to target antigen-null subset toxicity in the CD33 CAR and CD22 CAR treated groups was not observed. Interestingly, prolonged cytopenias are anecdotally observed in Phase I CAR trials, often attributed to heavy pretreatment of enrollees. Local inflammatory cytokine milieu, particularly IFNg, is implicated in marrow suppression in other settingsÑchronic viral infections, donor lymphocyte infusion and disseminated non-tuberculous mycobacterial infections. We hypothesize that prolonged CAR T cell cytokine secretion may exert similar marrow suppression. This could be due to either continuous CAR-engagement with reconstituting antigen-positive progenitors or an intrinsic supraphysiologic basal level of cytokine secretion by CAR T cells. We are currently analyzing cytokine profiles in our humanized murine model to further evaluate this hypothesis. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

scholarly journals Cancer-Homing CAR-T Cells and Endogenous Immune Population Dynamics

2021 ◽  
Vol 23 (1) ◽  
pp. 405
Author(s):  
Emanuela Guerra ◽  
Roberta Di Pietro ◽  
Mariangela Basile ◽  
Marco Trerotola ◽  
Saverio Alberti
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
The Body ◽  
Target Antigen ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Chimeric antigen receptor (CAR) therapy is based on patient blood-derived T cells and natural killer cells, which are engineered in vitro to recognize a target antigen in cancer cells. Most CAR-T recognize target antigens through immunoglobulin antigen-binding regions. Hence, CAR-T cells do not require the major histocompatibility complex presentation of a target peptide. CAR-T therapy has been tremendously successful in the treatment of leukemias. On the other hand, the clinical efficacy of CAR-T cells is rarely detected against solid tumors. CAR-T-cell therapy of cancer faces many hurdles, starting from the administration of engineered cells, wherein CAR-T cells must encounter the correct chemotactic signals to traffic to the tumor in sufficient numbers. Additional obstacles arise from the hostile environment that cancers provide to CAR-T cells. Intense efforts have gone into tackling these pitfalls. However, we argue that some CAR-engineering strategies may risk missing the bigger picture, i.e., that a successful CAR-T-cell therapy must efficiently intertwine with the complex and heterogeneous responses that the body has already mounted against the tumor. Recent findings lend support to this model.

scholarly journals CSPG4 as Target for CAR-T-Cell Therapy of Various Tumor Entities–Merits and Challenges

2019 ◽  
Vol 20 (23) ◽  
pp. 5942 ◽  
Author(s):  
Dennis C. Harrer ◽  
Jan Dörrie ◽  
Niels Schaft
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
B Cell Lymphoma ◽  
Target Antigen ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Targeting cancer cells using chimeric-antigen-receptor (CAR-)T cells has propelled adoptive T-cell therapy (ATT) to the next level. A plentitude of durable complete responses using CD19-specific CAR-T cells in patients suffering from various lymphoid malignancies resulted in the approval by the food and drug administration (FDA) of CD19-directed CAR-T cells for the treatment of acute lymphoblastic leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL). A substantial portion of this success in hematological malignancies can be traced back to the beneficial properties of the target antigen CD19, which combines a universal presence on target cells with no detectable expression on indispensable host cells. Hence, to replicate response rates achieved in ALL and DLBCL in the realm of solid tumors, where ideal target antigens are scant and CAR-T cells are still lagging behind expectations, the quest for appropriate target antigens represents a crucial task to expedite the next steps in the evolution of CAR-T-cell therapy. In this review, we want to highlight the potential of chondroitin sulfate proteoglycan 4 (CSPG4) as a CAR-target antigen for a variety of different cancer entities. In particular, we discuss merits and challenges associated with CSPG4-CAR-T cells for the ATT of melanoma, leukemia, glioblastoma, and triple-negative breast cancer.

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

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

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

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

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

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

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

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

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

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

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

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

scholarly journals Successful 24-Hours Manufacture of Anti-CD19/CD22 Dual Chimeric Antigen Receptor (CAR) T Cell Therapy for B-Cell Acute Lymphoblastic Leukemia (B-ALL)

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 2-3
Author(s):  
Junfang Yang ◽  
Pengfei Jiang ◽  
Xian Zhang ◽  
Jingjing Li ◽  
Yan Wu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Lymphoblastic Leukemia ◽  
Observation Time ◽  
High Dose ◽  
T Cell Therapy ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Introduction Multiple issues arise for a wider application of chimeric antigen receptor (CAR) T cell therapy including manufacturing time and antigen escape. Here we report data on an anti-CD19/CD22 dual CAR-T (GC022F) therapy based on a novel manufacturing platform, from a phase I clinical study (NCT04129099) in treating patients with B-cell acute lymphoblastic leukemia (B-ALL). Methods Peripheral blood (PB) mononuclear cells were obtained by leukapheresis. T-cells were separated and transduced with lentivirus that encodes a CD19/CD22 directed 4-1BB: ζ CAR. GC022F cells were manufactured using a novel FasTCARTM platform which takes 24 hours, while the conventional CD19/CD22 dual CAR-T (GC022C) cells used as parallel control in the preclinical study were manufactured by conventional process which typically takes 9-14 days. The phase I dose escalation study was initiated to explore the safety and efficacy of GC022F in patients with B-ALL. All patients received a conditioning regimen of IV fludarabine (25mg/m2/d) and cyclophosphamide (250mg/m2/d) for 3 days prior to GC022F infusion. Results When compared with the GC022C, GC022F cells showed 1) less exhaustion as indicated by lower percentage of PD-1+LAG3+ cells following co-culturing with tumor cells, 2) younger phenotypes as demonstrated by more abundant T central memory cells (Tcm; CCR7+CD45RA+ or CD45RO+CD62L+), 3) higher expansion fold at in vitro culture, and 4) high anti-leukemia efficacy in mice model (Fig.1). Comparing in vivo efficacy of GC022F with GC022C cells at lower doses, GC022F treatment were more potent and could reduce tumor burden earlier and faster, and led to significantly prolonged overall survival of the experimental animals. From Nov. 2019 to Jun. 2020, 9 children and 1 adult with B-ALL were enrolled and infused with GC022F, 2 in low-dose (6.0×104/kg), 7 in medium dose (1.0-1.5×105/kg), 1 in high-dose (2.25×105/kg). Patients' median observation time was 99 (14-210) days on the day of cut-off. Characteristics of enrolled patients are shown in Table 1. The median age was 10 (3-48) years, and the median bone marrow (BM) blasts were 21.0 (0.1-63.5) % at enrollment. Three patients had prior CD19 CAR-T cell therapy history and one of whom had prior allogeneic hematopoietic stem cell transplantation (allo-HSCT). After infusion, the median peak of circulating CAR-T cell copy number was 2.29 ×105 copies/µg genomic DNA (0.0014-5.66), which occurred around day 14 (day10 - day 28). Importantly, GC022F persisted well in PB with a median of 2.40×105 copies/µg genomic DNA (0.75-3.98) on day 28 in 5 of 9 patients with available 4 weeks of cellular kinetics data. GC022F exerted a superior safety profile with no observed grade ≥ 3 cytokine release syndrome (CRS) and neurotoxicity in all patients. Among those 6 patients with CRS, only 1 at high dose level had grade 2 CRS; only 1 developed grade 1 neurotoxicity. After GC022F infusion, 6/6 patients with BM blasts > 5% at enrollment achieved complete remission (CR) by day 28, 5/6 with minimal residual disease (MRD)-negative CR. For those 4 patients with MRD positive disease at enrollment, 3 became MRD-negative CR by day 28, 1 had persist MRD positive disease and withdrew from the study by 2 weeks. Five of 8 MRD-negative CR patients subsequently made a choice to pursue consolidation allo-HSCT with a median time interval of 57 (48-71) days post GC022F infusion and all have remained in MRD-negative CR except 1 died from graft-versus-host disease (GVHD) and infection 143 days post GC022F infusion. Of the other 3 patients without allo-HSCT, 2 relapsed with CD19+/CD22+ disease at 12-16 weeks follow-up, including the patient with prior history of CD19 CAR-T treatment and transplant. Conclusion This study demonstrated that anti-CD19/CD22 dual CAR T-cells could be successfully manufactured by FasTCARTM technology in 24 hours, with younger and less exhausted phenotypes. Moreover, the Dual FasTCAR-T cells showed more potent efficacy in xenograft mouse model compared to the conventional dual CAR-T cells. Our clinical data demonstrate that GC022F is safe and efficacious in treating patients with CD19+CD22+ B-ALL. More data on additional patients and longer observation time are needed to further evaluate CD19/CD22 dual FasTCAR-T cell product. Disclosures Cai: Gracell Biotechnologies Ltd: Current Employment. Wang:Gracell Biotechnologies Ltd: Current Employment. Chen:Gracell Biotechnologies Ltd: Current Employment. Ye:Gracell Biotechnologies Co., Ltd.: Current Employment. He:Gracell Biotechnologies Co., Ltd.: Current Employment. Cao:Gracell Biotechnologies Ltd: Current Employment. Sersch:Gracell Biotechnologies Co., Ltd.: Current Employment.

scholarly journals Allogeneic Hematopoietic Cell Transplantation Is Critical to Maintain Remissions after CD19-CAR T-Cell Therapy for Pediatric ALL: A Single Center Experience

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 39-40
Author(s):  
Aimee C Talleur ◽  
Renee M. Madden ◽  
Amr Qudeimat ◽  
Ewelina Mamcarz ◽  
Akshay Sharma ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
T Cell Therapy ◽  
Allogeneic Hct ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

CD19-CAR T-cell therapy has shown remarkable efficacy in pediatric patients with relapsed and/or refractory B-cell acute lymphoblastic leukemia (r/r ALL). Despite high short-term remission rates, many responses are not durable and the best management of patients who achieve a complete response (CR) post-CAR T-cell therapy remains controversial. In particular, it is unclear if these patients should be observed or proceed to consolidative allogeneic hematopoietic cell transplantation (HCT). To address this question, we reviewed the clinical course of all patients (n=22) who received either an investigational CAR T-cell product (Phase I study: SJCAR19 [NCT03573700]; n=12) or tisagenlecleucel (n=10) at our institution. The investigational CD19-CAR T cells were generated by a standard cGMP-compliant procedure using a lentiviral vector encoding a 2nd generation CD19-CAR with a FMC63-based CD19 binding domain, CD8a stalk and transmembrane domain, and 41BB.ζ signaling domain. Patients received therapy between 8/2018 and 3/2020. All products met manufacturing release specifications. Within the entire cohort, median age at time of infusion was 12.3 years old (range: 1.8-23.5) and median pre-infusion marrow burden using flow-cytometry minimal residual disease (MRD) testing was 6.8% (range: 0.003-100%; 1 patient detectable by next-generation sequencing [NGS] only). All patients received lymphodepleting chemotherapy (fludarabine, 25mg/m2 daily x3, and cyclophosphamide, 900mg/m2 daily x1), followed by a single infusion of CAR T-cells. Phase I product dosing included 1x106 CAR+ T-cells/kg (n=6) or 3x106 CAR+ T-cells/kg (n=6). Therapy was well tolerated, with a low incidence of cytokine release syndrome (any grade: n=10; Grade 3-4: n=4) and neurotoxicity (any grade: n=8; Grade 3-4: n=3). At 4-weeks post-infusion, 15/22 (68.2%) patients achieved a CR in the marrow, of which 13 were MRDneg (MRDneg defined as no detectable leukemia by flow-cytometry, RT-PCR and/or NGS, when available). Among the 2 MRDpos patients, 1 (detectable by NGS only) relapsed 50 days after CAR T-cell infusion and 1 died secondary to invasive fungal infection 35 days after infusion. Within the MRDneg cohort, 6/13 patients proceeded to allogeneic HCT while in MRDneg/CR (time to HCT, range: 1.8-2.9 months post-CAR T-cell infusion). All 6 HCT recipients remain in remission with a median length of follow-up post-HCT of 238.5 days (range 19-441). In contrast, only 1 (14.3%) patient out of 7 MRDneg/CR patients who did not receive allogeneic HCT, remains in remission with a follow up of greater 1 year post-CAR T-cell infusion (HCT vs. no HCT: p<0.01). The remaining 6 patients developed recurrent detectable leukemia within 2 to 9 months post-CAR T-cell infusion (1 patient detectable by NGS only). Notably, recurring leukemia remained CD19+ in 4 of 5 evaluable patients. All 4 patients with CD19+ relapse received a 2nd CAR T-cell infusion (one in combination with pembrolizumab) and 2 achieved MRDneg/CR. There were no significant differences in outcome between SJCAR19 study participants and patients who received tisagenlecleucel. With a median follow up of one year, the 12 month event free survival (EFS) of all 22 patients is 25% (median EFS: 3.5 months) and the 12 month overall survival (OS) 70% (median OS not yet reached). In conclusion, infusion of investigational and FDA-approved autologous CD19-CAR T cells induced high CR rates in pediatric patients with r/r ALL. However, our current experience shows that sustained remission without consolidative allogeneic HCT is not seen in most patients. Our single center experience highlights not only the need to explore maintenance therapies other than HCT for MRDneg/CR patients, but also the need to improve the in vivo persistence of currently available CD19-CAR T-cell products. Disclosures Sharma: Spotlight Therapeutics: Consultancy; Magenta Therapeutics: Other: Research Collaboration; CRISPR Therapeutics, Vertex Pharmaceuticals, Novartis: Other: Clinical Trial PI. Velasquez:St. Jude: Patents & Royalties; Rally! Foundation: Membership on an entity's Board of Directors or advisory committees. Gottschalk:Patents and patent applications in the fields of T-cell & Gene therapy for cancer: Patents & Royalties; TESSA Therapeutics: Other: research collaboration; Inmatics and Tidal: Membership on an entity's Board of Directors or advisory committees; Merck and ViraCyte: Consultancy.

scholarly journals CAR T-cell therapy of solid tumors: promising approaches to modulating antitumor activity of CAR T cells

2019 ◽  
pp. 5-12 ◽  
Author(s):  
Ya.Yu. Kiseleva ◽  
A.M. Shishkin ◽  
A.V. Ivanov ◽  
T.M. Kulinich ◽  
V.K. Bozhenko
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Solid Tumors ◽  
Functional Activity ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Adoptive immunotherapy that makes use of genetically modified autologous T cells carrying a chimeric antigen receptor (CAR) with desired specificity is a promising approach to the treatment of advanced or relapsed solid tumors. However, there are a number of challenges facing the CAR T-cell therapy, including the ability of the tumor to silence the expression of target antigens in response to the selective pressure exerted by therapy and the dampening of the functional activity of CAR T cells by the immunosuppressive tumor microenvironment. This review discusses the existing gene-engineering approaches to the modification of CAR T-cell design for 1) creating universal “switchable” synthetic receptors capable of attacking a variety of target antigens; 2) enhancing the functional activity of CAR T cells in the immunosuppressive microenvironment of the tumor by silencing the expression of inhibiting receptors or by stimulating production of cytokines.

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