Phase 1 Study of CART-ddBCMA, a CAR-T therapy utilizing a novel synthetic binding domain, for the treatment of subjects with relapsed and refractory multiple myeloma.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 8015-8015
Author(s):  
Matthew J. Frigault ◽  
Elizabeth O'Donnell ◽  
Noopur S. Raje ◽  
Daniella Cook ◽  
Andrew Yee ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
High Risk ◽  
T Cell Activation ◽  
Phase 1 ◽  
Binding Domain ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

8015 Background: CART-ddBCMA is an autologous CAR-T cell therapy encoding a novel non-scFv synthetic binding domain targeting BCMA with a 4-1BB costimulatory motif and CD3-zeta T-cell activation domain. The novel binding domain is based on a computationally-derived triple-helix protein scaffold that is small (73 amino acids), stable, engineered to reduce immunogenicity, and can be modified to bind alternative targets. Methods: ARC-101 (NCT04155749), ARM 1 (CART-ddBCMA) is a Phase 1, multi-center, open-label, dose escalation trial enrolling subjects who have received ≥3 prior regimens, including proteasome inhibitor(s), immuno-modulatory agent(s), and anti-CD38 antibody, or are triple-refractory. Subjects undergo lymphodepletion with fludarabine and cyclophosphamide, then receive CART-ddBCMA as a single infusion. Planned dose levels are 100, 300, and up to 900 x 106 CAR+ T cells. The primary endpoint is incidence of adverse events (AEs), including dose-limiting toxicities (DLTs). Secondary endpoints include clinical response per IMWG criteria, MRD, DOR, PFS, OS, and CAR-T cell kinetics. Results: As of 29 Jan 2021, 10 subjects received CART-ddBCMA, 9 subjects were evaluable, and 1 subject was pending assessment. Median age was 66 years [min:max 54 to 75]. 6 subjects received 100 x 106 CAR+ T cells, and 4 subjects received 300 x 106 CAR+ T cells. Median CAR+ expression was 74.5% (min:max 61-87%) of total T cells. Of the evaluable subjects, median follow-up after cell infusion was 208 days (min:max 45 to 355+ days), 9/9 subjects were penta-refractory, 1 subject was also refractory to BCMA-directed ADC. 8/9 had high-risk cytogenetics (1 subject’s sample not evaluable), and 6/9 subjects had extramedullary disease. No DLTs were reported. Per ASTCT Consensus Grading (Lee et al, 2019), 8 subjects developed G1/2 CRS, 1 subject in the higher dose cohort developed G3 CRS that rapidly resolved with tocilizumab. 1 subject developed G2 ICANS which rapidly resolved with intervention. 7 subjects received tocilizumab; 3 received dexamethasone. ORR was 100% (9/9) per IMWG criteria including 4 sCR, 1 VGPR, and 4 PR. 1 subject with PR relapsed and was retreated. All other subjects have ongoing responses; observations included sFLC normalization and elimination of detectable bone marrow disease by Month 1. Ongoing responses for subjects not yet achieving CR continue to deepen. 7 subjects were evaluable by MRD of which 5 are MRD-negative, and 2 are pending results. CAR-T cell expansion, as measured by vector transgene copies per microgram genomic DNA was observed in all patients. Conclusions: Early efficacy results are encouraging, with 9/9 (100%) ORR and manageable toxicities. 8/9 responses are ongoing and responses continue to deepen. These data are encouraging in high-risk subjects with penta-refractory myeloma. Subjects continue to be enrolled and treated. Clinical trial information: NCT04155749.

Updated results from ZUMA-3, a phase 1/2 study of KTE-C19 chimeric antigen receptor (CAR) T cell therapy, in adults with high-burden relapsed/refractory acute lymphoblastic leukemia (R/R ALL).

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 3024-3024 ◽  
Author(s):  
Bijal D. Shah ◽  
William G. Wierda ◽  
Gary J. Schiller ◽  
Michael Russell Bishop ◽  
Januario E. Castro ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Disease Burden ◽  
Phase 1 ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

3024 Background: Promising results have been observed with KTE-C19, an anti-CD19 CAR T cell therapy, in refractory aggressive NHL in the ZUMA-1 trial (Blood 2016;128:LBA-6). We present here updated results from the ZUMA-3 phase 1 trial of KTE-C19 in adult patients (pts) with R/R ALL. Methods: Adult (≥18 y) pts with R/R ALL (Ph+ eligible), ≥25% bone marrow (BM) blasts, adequate organ function and ECOG status 0-1 received 1 or 2×106 CAR T cells/kg after conditioning with cyclophosphamide + fludarabine. Phase 1 primary endpoint is incidence of dose-limiting toxicity (DLT). Secondary endpoints include efficacy outcomes and biomarker associations. Results: As of Nov 1, 2016, 11 pts were enrolled; 10 received KTE-C19. One pt had a serious adverse event (SAE) prior to dosing and was not treated. KTE-C19 was successfully manufactured in all pts across a broad range of baseline absolute lymphocyte counts in 6 days in a centralized facility, with an approximate 2-week turnaround time. Pts were 60% men with 1-4 prior lines of therapy and high disease burden (median, 70% BM blasts). No pt (0/3) experienced a DLT at the 2×106 dose. Phase 1 was expanded to 6 pts at the same dose; 1 grade (Gr) 5 AE (multiorgan failure due to cytokine release syndrome [CRS]) was observed. Subsequent pts (4) received 1×106 CAR T cells/kg. Overall, the most common Gr≥3 AEs were cytopenias (80%), febrile neutropenia (50%), pyrexia (40%), and transaminitis (40%). Gr≥3 CRS and neurologic events (NEs) were reported in 20% and 40% of pts, respectively. Cerebral edema was not observed. All CRS (except Gr5) and 5 of 6 NEs (1 Gr3 ongoing at cut-off) resolved. Of the 8 efficacy evaluable pts, 6 achieved an MRD-negative (MRD–) complete response (CR, or CR + partial or incomplete hematopoietic recovery). Updated results will include additional pt follow-up and biomarker data. Conclusions: No DLTs were observed with KTE-C19 in adult pts with high BM disease burden; one pt had G5 CRS after the DLT cohort. Manufacturing was successful in all pts; most pts achieved an MRD– CR. Based on these results, ZUMA-3 continues to enroll pts with additional measures implemented to further enhance safety. Clinical trial information: NCT02614066.

scholarly journals Engineered Cytokine Signaling to Improve CAR T Cell Effector Function

2021 ◽  
Vol 12 ◽  
Author(s):  
Matthew Bell ◽  
Stephen Gottschalk
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Expansion ◽  
Cytokine Signaling ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
T Cell Expansion

Adoptive immunotherapy with T cells genetically modified to express chimeric antigen receptors (CARs) is a promising approach to improve outcomes for cancer patients. While CAR T cell therapy is effective for hematological malignancies, there is a need to improve the efficacy of this therapeutic approach for patients with solid tumors and brain tumors. At present, several approaches are being pursued to improve the antitumor activity of CAR T cells including i) targeting multiple antigens, ii) improving T cell expansion/persistence, iii) enhancing homing to tumor sites, and iv) rendering CAR T cells resistant to the immunosuppressive tumor microenvironment (TME). Augmenting signal 3 of T cell activation by transgenic expression of cytokines or engineered cytokine receptors has emerged as a promising strategy since it not only improves CAR T cell expansion/persistence but also their ability to function in the immunosuppressive TME. In this review, we will provide an overview of cytokine biology and highlight genetic approaches that are actively being pursued to augment cytokine signaling in CAR T cells.

scholarly journals A Bispecific CAR-T Cell Therapy Targeting Bcma and CD38 for Relapsed/Refractory Multiple Myeloma: Updated Results from a Phase 1 Dose-Climbing Trial

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 930-930 ◽  
Author(s):  
Chenggong Li ◽  
Heng Mei ◽  
Yu Hu ◽  
Tao Guo ◽  
Lin Liu ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Phase 1 ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Background: Anti-B cell maturation antigen (BCMA) chimeric antigen receptor(CAR) T cell therapy has shown promising results from a series of clinical trials. But short progression-free survival (PFS) due to BCMA-negative or positive relapse is pretty much the agenda.Here we constructed a dual-target BM38 CAR incorporating the anti-CD38 and anti-BCMA single-chain variable fragment in tandem plus 4-1BB signaling and CD3 zeta domains and conducted the first-in-human clinical trial(ChiCTR1800018143) in patients with RRMM to evaluate the safety, efficacy and duration of BM38 T cells. Methods:Patients with relapsed or refractory multiple myeloma(RRMM), who had received at least 2 prior treatment regimens, including a proteasome inhibitor and an immunomodulatory agent, were enrolled in the phase 1 dose-climbing trial of the bispecific CAR-T cell therapy. Patients were subjected to a lymphodepleting regimen with Cy(250 mg/m2, d-5 to d-3) and Flu(25 mg/m2, d-5 to d-3) daily prior to the CAR-T infusion (d0). The dose gradients of infused CAR-T cells were 0.5, 1.0, 2.0, 3.0 and 4.0×106 cells/kg and at least 2 patients were involved at every dose level. The efficacy was assessed by the International Uniform Response Criteria for Multiple Myeloma (2016), and the toxicity was graded by CTCAE 5.0. Results: As of 31 July 2019, 16 pts consisting of 10(62.5%) with genetic abnormalities and 5(31.25%) with extramedullary lesions,had received BM38 CAR-T cells in the 5 dose-climbing cohorts. At a median follow-up of 36 weeks, no DLTs and no grade ≥ 3 neurotoxicities were observed. Cytokine release syndrome (CRS), mainly grade 1-2, was reported in 10 of 16 (62.5%) pts; 4 pts had grade ≥ 3 CRS that resolved by tocilizumab and supportive treatment. Almost all the pts were observed with hematological toxicities relieved in the first month after infusion.14(87.5%) pts achieved an overall response with 8(50%) sCR, 2(12.5%) VGPR and 4(25.00%) PR and 14(87.5%) reached bone marrow minimal residual disease(MRD)-negative status. The longest duration of sCR was over 51 weeks and 5(62.5%) of 8 patients had still maintained sCR and 2 transformed to VGPR and 1 to PR. The median duration of progression-free survival(PFS) had not been reached; PFS rates at 9 months was 75%. More encouragingly, 5(100%)extramedullary lesions were eliminated.Up to the observed day, the BM38 CAR-T cells still exist in the patients' peripheral blood by flow cytometry(FCM) and quantitative polymerase chain reaction(q-PCR). The peak time of CAR-T cells proliferation of sCR patients was about the 2nd week after infusion, which was earlier than other patients. 4.0 × 106 CAR T cells (pt11, 12 and 15) were selected for the optimal dose with superior response and acceptable toxicities and expansion cohort would be conducted. Conclusions:Our study demonstrates an improved efficacy with the bivalent BM38 CAR-T therapy for RRMM with a high ORR, especially a higher rate and a longer duration of sCR and effective elimination for extramedullary lesions. No neurotoxicity was observed. CRS and other toxicities were manageable. These initial data provide strong evidence to support the further development of the dual-target CAR-T therapy for RRMM. Clinical trial information: ChiCTR1800018143 Disclosures No relevant conflicts of interest to declare.

scholarly journals Updated Analysis of a Phase 1, Open-Label Study of LCAR-B38M, a Chimeric Antigen Receptor T Cell Therapy Directed Against B-Cell Maturation Antigen, in Patients with Relapsed/Refractory Multiple Myeloma

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 955-955 ◽  
Author(s):  
Wan-Hong Zhao ◽  
Jie Liu ◽  
Bai-Yan Wang ◽  
Yin-Xia Chen ◽  
Xing-Mei Cao ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Median Duration ◽  
Phase 1 ◽  
Open Label ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Grade 3

Abstract LCAR-B38M is a bispecific chimeric antigen receptor T cell (CAR T) therapy directed against B-cell maturation antigen (BCMA). The bi-epitope BCMA binding moieties confer high avidity binding and distinguish LCAR-B38M from other BCMA CAR constructs. Preliminary results of LCAR-B38M in patients (pts) with relapsed/refractory (R/R) multiple myeloma (MM) showed encouraging efficacy and manageable safety (Fan et al.JCO 2017;35:18_suppl LBA3001). Here we present updated safety and efficacy results of the trial. LEGEND-2 (NCT03090659) is an ongoing phase 1, single-arm, open-label multicenter study evaluating LCAR-B38M in pts (18-80 years) with R/R MM. Lymphodepletion was performed using 3 doses of cyclophosphamide 300 mg/m2 on days -5, -4, and -3. Five days after lymphodepletion, LCAR-B38M CAR T cells (median CAR+ cell dose = 0.5x106 cells/kg, [range, 0.07-2x106]) were given in 3 infusions (20, 30, and 50% of total dose). The primary objective is to evaluate the safety of LCAR-B38M CAR T cells; the secondary objective is to evaluate the anti-myeloma response of the treatment. Adverse events (AEs) were graded using the Common Terminology Criteria for AE, v.4.03, and cytokine release syndrome (CRS) was assessed according to Lee et al. (Blood 2014;124:188-95). Response was evaluated using International Myeloma Working Group criteria. This analysis presents data from a single institution. As of June 25, 2018, 57 pts have been infused with LCAR-B38M CAR T cells. The median age was 54 years (range, 27-72), median number of prior therapies was 3 (range, 1-9), and 74% of pts had stage III disease by Durie-Salmon staging. The median duration of follow-up for all pts was 12 months (range, 0.7-25). AEs were reported by all pts; most common were pyrexia (91%), CRS (90%), thrombocytopenia (49%), and leukopenia (47%). Grade ≥3 AEs were reported by 65% of pts; most common were leukopenia (30%), thrombocytopenia (23%), and increased aspartate aminotransferase (21%). CRS was mostly grade 1 (47%) and 2 (35%); 4 pts (7%) had grade 3 cases. Liver function abnormalities were the most common signs of end organ injury among pts with CRS. The median time to onset of CRS was 9 days (range, 1-19). All but 1 CRS events resolved, with a median duration of 9 days (range, 3-57). No clear relationship was demonstrated between dose and CRS; there may be some effect at higher doses, but conclusions are limited by the small number of pts in the grade 3 CRS group (n=4; Figure 1A). Neurotoxicity was observed in 1 pt who had grade 1 aphasia, agitation, and seizure-like activity. The overall response rate (partial response [PR] or better) was 88% (95% confidence interval [CI], 76-95). Complete response (CR) was achieved by 42 pts (74%; 95% CI, 60-85), very good partial response was achieved by 2 pts (4%; 95% CI, 0.4-12), and PR was achieved by 6 pts (11%; 95% CI, 4-22; Figure 1B). Among pts with CR, 39/42 were minimal residual disease (MRD) negative by 8-color flow cytometry. The median time to initial response was 1 month (range, 0.4-4). No clear relationship between LCAR-B38M CAR T cell dose and response was observed (Figure 1C). BCMA expression did not correlate with clinical response. The median duration of response (DOR) was 16 months (95% CI, 12-not reached [NR]). The median DOR for pts who achieved a CR was 22 months (95% CI, 14-NR). At data cutoff, 18 pts (36%) who achieved PR or better progressed. The median progression-free survival (PFS) for all treated pts was 15 months (95% CI, 11-NR); median PFS for pts who achieved CR was 24 months (95% CI, 15-NR). The median overall survival was not reached. Overall, 17 pts died during the study and follow-up period; causes of death were progressive disease (PD; n=14), suicide after PD (n=1), esophagitis (n=1), and pulmonary embolism and acute coronary syndrome (n=1). Peak levels of LCAR-B38M (≥1x104 copies/µg genomic DNA) were observed in a majority of pts with blood samples for analysis (n=32). LCAR-B38M CAR T cells were not detectable in peripheral blood in 71% of pts at 4 months; 5 pts showed CAR T cell persistence up to 10 months. This ongoing first-in-human study has provided initial proof-of-concept that bispecific LCAR-B38M CAR T cells may be a highly effective therapy for R/R MM. LCAR-B38M CAR T cell therapy displayed a manageable safety profile consistent with its known mechanism of action and demonstrated deep and durable responses in pts with R/R MM. A phase 1/2 study of LCAR-B38M in R/R MM has been initiated in the US (NCT03548207). Disclosures Zhuang: Nanjing Legend Biotech: Employment. Fan:Nanjing Legend Biotech: Employment.

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 IMMU-03. UPDATES ON BRAINCHILD-01, -02, AND -03: PHASE 1 LOCOREGIONAL CAR T CELL TRIALS TARGETING HER2, EGFR, AND B7-H3 FOR CHILDREN WITH RECURRENT CNS TUMORS AND DIPG

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii360-iii360
Author(s):  
Nicholas Vitanza ◽  
Juliane Gust ◽  
Ashley Wilson ◽  
Wenjun Huang ◽  
Francisco Perez ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Phase 1 ◽  
Signs And Symptoms ◽  
Preliminary Evidence ◽  
Cns Tumors ◽  
Disease Response ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Abstract We report preliminary results of three Phase 1 trials of repetitively dosed locoregional CAR T cells for children with recurrent/refractory CNS tumors, targeting HER2 (BrainChild-01), EGFR (BrainChild-02), and B7-H3 (BrainChild-03). Cells are delivered into the tumor cavity (Arm A) or ventricular system (Arm B and BrainChild-03’s DIPG-specific Arm C). Primary endpoints are feasibility and safety. Successful CAR T cell manufacture occurred in 2/2 subjects (BrainChild-01) and 2/3 (BrainChild-02). All subjects tolerated intra-patient dose escalation from 1x107 to 2.5x107 cells/dose without DLTs. Two subjects were evaluable on BrainChild-01 (S-001: glioblastoma, Arm A, survival 173 days post-first infusion, received 6 infusions; S-002: ependymoma, Arm B, survival 111 days, 9 infusions). One subject was evaluable on BrainChild-02 (glioblastoma, Arm A, withdrew from trial at 49 days, 5 infusions). One enrolled patient on BrainChild-03 has not begun treatment. None of the subjects developed new neurologic toxicities, although transient worsening of baseline tumor-related signs and symptoms were seen. Secondary endpoints are efficacy and disease response. No objective radiographic responses have been observed. Both BrainChild-01 subjects had transient systemic CRP elevations following infusions (S-001: peak of 3.9 post Course 1 Week 1; S-002: peak of 2.3 post Course 2 Week 1), possibly indicating an inflammatory response. Both subjects had post-infusion CSF cytokine elevations (CXCL10, GCSF, GM-CSF, IFNa2, IFNg, IL-10, IL12-p40, IL12-p70, IL-15, IL-1a, IL-3, IL-6, IL-7, TNFa, VEGF) without concurrent systemic changes. In summary, we provide preliminary evidence of safety and feasibility of intracranial delivery of CAR T cells for pediatric CNS tumors.

scholarly journals Engineering Next-Generation CAR-T Cells for Better Toxicity Management

2020 ◽  
Vol 21 (22) ◽  
pp. 8620
Author(s):  
Alain E. Andrea ◽  
Andrada Chiron ◽  
Stéphanie Bessoles ◽  
Salima Hacein-Bey-Abina
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antigen Receptors ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Safety Strategies ◽  
Life Threatening ◽  
Preclinical And Clinical Studies

Immunoadoptive therapy with genetically modified T lymphocytes expressing chimeric antigen receptors (CARs) has revolutionized the treatment of patients with hematologic cancers. Although clinical outcomes in B-cell malignancies are impressive, researchers are seeking to enhance the activity, persistence, and also safety of CAR-T cell therapy—notably with a view to mitigating potentially serious or even life-threatening adverse events like on-target/off-tumor toxicity and (in particular) cytokine release syndrome. A variety of safety strategies have been developed by replacing or adding various components (such as OFF- and ON-switch CARs) or by combining multi-antigen-targeting OR-, AND- and NOT-gate CAR-T cells. This research has laid the foundations for a whole new generation of therapeutic CAR-T cells. Here, we review the most promising CAR-T cell safety strategies and the corresponding preclinical and clinical studies.

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 P07.02 Regulation of CD19 CAR T- cell activation based on engineered Nuclear factor of activated T cells artificial transcription factors

2021 ◽  
Vol 9 (Suppl 1) ◽  
pp. A23-A23
Author(s):  
D Lainšček ◽  
V Mikolič ◽  
Š Malenšek ◽  
A Verbič ◽  
R Jerala
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cell Activity ◽  
External Control ◽  
Car T Cells ◽  
Car T Cell ◽  
Artificial Transcription Factors ◽  
Car T

BackgroundCD19 CAR T- cells (Chimeric antigen receptor T cells that recognize CD19) present a therapeutic option for various malignant diseases based on their ability to specifically recognize the selected tumour surface markers, triggering immune cell activation and cytokine production that results in killing cancerous cell expressing specific surface markers recognized by the CAR. The main therapeutic effect of CAR is a specific T cell activation of adequate cell number with sequential destruction of tumorous cells in a safe therapeutic manner. In order to increase T cell activation, different activation domains were introduced into CAR. CAR T-cells are highly efficient in tumour cell destruction, but may cause serious side effects that can also result in patient death so their activity needs to be carefully controlled.1 Several attempts were made to influence the CAR T cell proliferation and their activation by adding T cell growth factors, such as IL-2, into patients, however this approach of increasing the number of activating T cells with no external control over their number can again lead to non-optimal therapeutic effects. Different improvements were made by designing synthetic receptors or small molecule-inducible systems etc., which influence regulated expansion and survival of CAR T cells.2Material and MethodsIn order to regulate CD19 CAR-T cell activity, different NFAT2 based artificial transcription factors were prepared. The full length NFAT2, one of the main players in T cell IL2 production, a key cytokine for T cell activation and proliferation was truncated by deletion of its own activation domain. Next, we joined via Gibson assembly tNFAT21-593 coding sequence with domains of different heterodimerization systems that interact upon adding the inductor of heterodimerization. The interaction counterparts were fused to a strong tripartite transcriptional activator domain VPR and/or strong repressor domain KRAB resulting in formation of an engineered NFAT artificial transcription (NFAT-TF) factors with external control. To determine the activity of NFAT-TF HEK293, Jurkat or human T cells were used.ResultsBased on luciferase assay, carried out on NFAT-TF transfected HEK293 cells we first established that upon adding the external inductor of heterodimerization, efficient gene regulation occurs, according to VPR or KRAB domain appropriate functions. Findings were then transferred to Jurkat cells that were electroporated with appropriate DNA constructs, coding for NFAT-TF and CD19 CAR. After Raji:Jurkat co-culture ELISA measurements revealed that IL2 production and therefore CD19 CAR-T cell activity can be controlled by the action of NFAT-TF. The same regulation over the activity and subsequent proliferation status was also observed in retrovirally transduced human T-cells.ConclusionWe developed a regulatory system for therapeutic effect of CD19 CAR-T cells, a unique mechanism to control T cell activation and proliferation based on the engineered NFAT2 artificial transcription factor.ReferencesBonifant CL, et al. Toxicity and management in CAR T-cell therapy. Mol Ther Oncolytics 2016;3:16011.Wu C-Y, et al. Remote control of therapeutic T cells through a small molecule-gated chimeric receptor. Science 2015;80:350.Disclosure InformationD. Lainšček: None. V. Mikolič: None. Š. Malenšek: None. A. Verbič: None. R. Jerala: None.

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