scholarly journals A Phase I Study of CD19-Targeted 19(T2)28z1xx CAR T Cells in Adult Patients with Relapsed or Refractory B-Cell Malignancies

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 43-44
Author(s):  
Jae H. Park ◽  
Isabelle Riviere ◽  
Devanjan S. Sikder ◽  
Vladimir P. Bermudez ◽  
Brigitte Senechal ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Dose Escalation ◽  
Research Funding ◽  
High Grade ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Background: Autologous CAR T cell therapy targeting the B-cell specific surface antigen CD19 has demonstrated favorable clinical responses in relapsed or refractory (R/B) B-cell lymphomas (BCL). However, despite 40-60% initial complete response (CR) rates, only a subset of patients experience durable remissions, and there is a need to further improve the efficacy of CAR therapies by preventing relapse and attaining a deeper CR. We hypothesized that the redundancy of CD28 and CD3V signaling in a CAR design incorporating all 3 CD3Vimmunoreceptor tyrosine-based activation motifs (ITAMs) might foster counterproductive T cell differentiation and exhaustion, and therefore created a new CD19 CAR construct with calibrated CAR activation potential by mutating 2 of the 3 ITAMs, termed 1XX. In systemic ALL mouse models, 19-28z1XX CAR induced effective tumor eradication at low CAR T cell doses with improved survival compared to conventional 19-28z CAR. Further preclinical studies demonstrated that the enhanced therapeutic benefit resulted from the reduced strength of activation mediated by the 19-28z1XX CAR, achieving a favorable balance of effector and memory functions, thereby enhancing persistence of functional CAR T cells and promoting effective elimination of CD19+ leukemia at lower T cell doses than needed with 19-28z CAR T cells (Feucht J et al. Nat Med 2019). To further improve the persistence of functional CAR T cells, we screened different humanized CD19-directed scFv in the context of a 19-28z1XX CAR design and proved high specificity and functionality of 19-28z1XX CARs containing a novel humanized scFv T2 - termed 19(T2)28z1XX. Study Design and Methods: This study is a single center Phase I clinical trial of 19(T2)28z1XX in patients with R/R B-cell malignancies at Memorial Sloan Kettering Cancer Center (NCT04464200). Key disease eligibility criteria include R/R diffuse large B cell lymphoma (DLBCL), high grade BCL, primary mediastinal BCL, indolent BCL and chronic lymphocytic leukemia (CLL). Patients with prior CD19 CAR therapies are eligible as long as expression of CD19 is confirmed. Key exclusion criteria include ongoing immunosuppression such as systemic GvHD therapy and active CNS disease. The study uses a 3+3 dose-escalation design to identify the maximum tolerated dose for BCL. There are 5 planned flat-dose levels. Patients will receive conditioning chemotherapy consisting of 3 days of fludarabine and cyclophosphamide followed by a single infusion of 19(T2)28z1XX CAR T cells. In the dose-escalation phase, patients with DLBCL, high grade BCL, and primary mediastinal BCL are eligible to participate. Once the recommended phase 2 dose (RP2D) is determined, the study will open to dose expansion phase with two cohorts. Cohort 1 includes DLBCL, high grade BCL and primary mediastinal BCL (i.e. same eligibility criteria as the dose-escalation phase). Cohort 2 will include patients with indolent BCL, CLL, and Richter's transformation. The dose-expansion part of the trial is designed to further characterize the safety, efficacy, and pharmacokinetics of 19(T2)28z1XX CAR in multiple indications. The primary objective of the trial is to evaluate safety and tolerability and determine the recommended Phase 2 dose of 19(T2)28z1XX. Key secondary objectives include evaluation of 19(T2)28z1XX's efficacy and cellular kinetics. Exploratory objectives include assessment of B cell aplasia, and analysis of serum cytokines. The trial has begun enrollment in August 2020. The investigators are hopeful this study will lead to development of improved CD19 CAR T cell therapy with enhanced efficacy and favorable toxicity profiles with lower infused T cell dose. Disclosures Park: AstraZeneca: Consultancy; Servier: Consultancy, Research Funding; Autolus: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Novartis: Consultancy; Minverva: Consultancy; Artiva: Membership on an entity's Board of Directors or advisory committees; Fate Therapeutics: Research Funding; Kite: Consultancy, Research Funding; Incyte: Consultancy, Research Funding; Genentech/Roche: Research Funding; Juno Therapeutics: Research Funding; GSK: Consultancy; Intellia: Consultancy; Allogene: Consultancy. Riviere:Fate Therapeutics Inc.: Consultancy, Other: Ownership interest , Research Funding; FloDesign Sonics: Consultancy, Other: Ownership interest; Juno Therapeutics: Other: Ownership interest, Research Funding; Takeda: Research Funding; Atara: Research Funding. Palomba:Genentech: Research Funding; Juno Therapeutics, a Bristol-Meyers Squibb Company: Honoraria, Research Funding; Regeneron: Research Funding; Novartis: Honoraria; Merck: Honoraria; Celgene: Honoraria; Pharmacyclics: Honoraria. Brentjens:BMS: Research Funding; Gracell Therapeutics: Consultancy; Juno Therapeutics (a Bristol Myers Squibb company): Patents & Royalties. Sadelain:Atara: Patents & Royalties, Research Funding; Fate Therapeutics: Patents & Royalties, Research Funding; Minerva: Other: Biotechnologies , Patents & Royalties; Mnemo: Patents & Royalties; Takeda: Patents & Royalties, Research Funding. OffLabel Disclosure: Cyclophosphamide and fludarabine will be used as conditioning therapy prior to 19(T2)28z1XX CAR T cell administration.

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

Anti-CD19 Chimeric Antigen Receptor-Modified T Cell Therapy for B Cell Non-Hodgkin Lymphoma and Chronic Lymphocytic Leukemia: Fludarabine and Cyclophosphamide Lymphodepletion Improves In Vivo Expansion and Persistence of CAR-T Cells and Clinical Outcomes

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 184-184 ◽  
Author(s):  
Cameron J Turtle ◽  
Carolina Berger ◽  
Daniel Sommermeyer ◽  
Laila-Aicha Hanafi ◽  
Barbara Pender ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Research Funding ◽  
T Cell Subsets ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Clinical Responses

Abstract BACKGROUND: Autologous T cells genetically modified to express a CD19-specific chimeric antigen receptor (CAR) have demonstrated activity in patients with relapsed or refractory B cell NHL and CLL. The functional heterogeneity that is inherent in CAR-T cell products that are manufactured from undefined T cell subsets has hindered definition of dose-response relationships and identification of factors that may impact efficacy and toxicity, such as the lymphodepletion regimen and infused cell dose. We manufactured anti-CD19 CAR-T cells from a defined composition of CD4+ and CD8+ T cell subsets to treat adults with relapsed or refractory B cell NHL or CLL. T cell subsets were enriched from each patient, transduced with a CD19 CAR lentivirus and separately expanded in vitro before formulation for infusion in a 1:1 ratio of CD8+:CD4+ CAR+ T cells at one of three dose levels (2x105, 2x106 or 2x107 CAR-T cells/kg). CAR-T cells were administered 48-96 hours after lymphodepletion with either cyclophosphamide (Cy, 60 mg/kg)+/- etoposide or Cy (60 mg/kg) and fludarabine (25 mg/m2 daily for 3-5 days (Cy/Flu). RESULTS: Adult patients with relapsed/refractory CD19 expressing B cell NHL (n=28, median age 59 years, range 36-70) or CLL (n=6, median age 60 years, range 54-64) were treated with at least one CAR-T cell infusion. NHL histologies include diffuse large B cell or transformed NHL (DLBCL, n=18), follicular NHL (FL, n= 6) or mantle cell lymphoma (MCL, n=4). 15 patients had failed prior autologous (n=13) or allogeneic (n=3) transplants. Twelve of the 28 NHL patients received lymphodepletion with Cy-based regimens without fludarabine. Expansion of CAR-T cells and clinical responses were observed in 50% (CR=1 (DLBCL), PR=5 (2 FL, 2 DLBCL, 1 MCL), no response=6). Patients were treated at all three dose levels without dose limiting toxicity or severe cytokine release syndrome (sCRS). With this regimen, we observed short CAR-T cell persistence in most patients and demonstrated a CD8-mediated immune response to the murine scFv component of the CAR transgene that correlated with loss of CAR-T cells. Retreatment with CAR-T cells with or without chemotherapy in 5 patients led to no significant T cell expansion or clinical responses. To minimize transgene rejection fludarabine was added to the lymphodepletion regimen administered to the subsequent 16 NHL patients. Clinical responses were evaluated in 12 of 16 patients (2 not yet evaluable, 2 early deaths). Addition of Flu to the lymphodepletion regimen increased the CR rate to 42%, compared to 8% with Cy alone. Clinical responses were identified in 6 of 8 patients with DLBCL (3 CR, 3 PR) and 2 of 3 patients with FL (2 CR). The overall response rate was 67%. We noted higher peak CAR-T cell levels in blood in the Cy/Flu group (n=13) compared with the Cy only group (n=11) (CD8+ CAR-T cells, median 31.9 cells/ml vs 0.55 cells/ml, p = 0.009; CD4+ CAR-T cells, median 16.5 cells/ml vs 0.31 cells/ml, p= 0.007), and CAR-T cell persistence was longer in Flu-treated patients (see Figure 1 for patients treated at 2 x 107/kg). Surprisingly, 2 of 7 patients who received 2 x 107 CAR-T cells/kg experienced dose-limiting toxicity necessitating dose de-escalation. Markedly elevated IL-6 levels were observed within the first day after CAR-T cell infusion in patients who subsequently developed severe toxicity, which may provide an opportunity to test early interventional approaches to minimize toxicity. Six patients with relapsed and refractory CLL received CAR-T cells. Five of 6 restaged patients had complete clearance of blood and/or marrow disease by high-resolution flow cytometry 4 weeks following treatment. Overall clinical responses included 3 CR, 1 PR and 2 no response. One patient with a PR died from refractory pulmonary aspergillus infection. Patients with CR remain in remission at 1-10 months after therapy. CONCLUSION: Immunotherapy with CD19 CAR-T cells of defined subset composition is feasible in patients with NHL and CLL and has potent anti-tumor activity. Toxicity is related to cell dose. The addition of Flu to a Cy-based lymphodepletion regimen results in greater CAR-T cell expansion and persistence, and improves the CR rate after CD19 CAR-T cell therapy. Disclosures Turtle: Juno Therapeutics: Patents & Royalties, Research Funding. Berger:Juno Therapeutics: Patents & Royalties. Jensen:Juno Therapeutics: Equity Ownership, Patents & Royalties, Research Funding. Riddell:Juno Therapeutics: Equity Ownership, Patents & Royalties, Research Funding; Cell Medica: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy. Maloney:Juno Therapeutics: Research Funding; Janssen Scientific Affairs: Honoraria; Seattle Genetics: Honoraria; Roche/Genentech: Honoraria.

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

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

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

scholarly journals B-CLL Mediated Resistance to CAR T Cell Therapy Via Insufficient Activation Is CAR-Independent

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 44-44
Author(s):  
McKensie Collins ◽  
Weimin Kong ◽  
Inyoung Jung ◽  
Stefan M Lundh ◽  
J. Joseph Melenhorst
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Research Funding ◽  
Cytokine Production ◽  
Cell Function ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Chronic Lymphocytic Leukemia (CLL) is a B cell malignancy that accounts for nearly 1/3rd of adult leukemia diagnoses in the Western world. Conventional chemo-immunotherapies initially control progression, but in the absence of curative options patients ultimately succumb to their disease. Chimeric Antigen Receptor (CAR) T cell therapy is potentially curative, but only 26% of CLL patients have a complete response. CLL-stimulated T cells have reduced effector functions and B-CLL cells themselves are believed to be immunosuppressive. Our work demonstrates that insufficient activation of CAR T cells by CLL cells mediates some of these effects and that the results are conserved between ROR1- and CD19-targeting CARs. Results: In this study we used an in vitro system to model the in vivo anti-tumor response in which CAR T cells serially engage with CLL cells. Multiple stimulations of CD19 or ROR1-targeting CAR T cells with primary CLL cells recapitulated many aspects of known T cell dysfunction including reduced proliferation, cytokine production, and activation. While the initial stimulation induced low level proliferation, subsequent stimulations failed to elicit additional effector functions. We further found that these functional defects were not permanent, and that CAR T cell function could be restored by switching to a stimulus with an aAPC (artificial Antigen Presenting Cell) control cell line. The aAPCs are well-characterized as potent stimulators of CAR T cell effector responses. Flow cytometry revealed that CLL-stimulated CAR T cells retained a non-activated, baseline differentiation profile, suggesting that CLL cells fail to stimulate CAR T cells rather than rendering them non-functional. One mechanism that could dampen activation is immune suppression. We assessed this at a high level by stimulating CAR T cells with CLL cells and aAPCs mixed at known ratios. However, even cultures containing 75% CLL cells stimulated proliferation and cytokine production. Extensive immune-phenotyping revealed high level expression of the IL-2 Receptor on 90% (18/20) of the B-CLL cells tested. Since cytokine sinking via IL-2 receptor expression is a well-known mechanism of regulatory T cell suppression, we hypothesized that CLL cells similarly sink IL-2, blunting T cell activation. To test this, we supplemented IL-2 into CLL/CAR T cell co-cultures and showed that this rescued proliferation but only partially restored cytokine production. In contrast to our hypothesis, analysis of cytokine production by flow cytometry showed that CLL-stimulated CAR T cells did not produce IL-2 following a 6- or 12-hour stimulus, but TNFα was expressed after 12-hours. Similarly, CAR T cell degranulation, a prerequisite for target cell lysis was triggered after CLL recognition. These data again suggested that CLL cells insufficiently stimulate CAR T cell cytokine production, but also showed that cytolytic activity against CLL cells is intact. We further proposed that CLL cells express insufficient levels of co-stimulatory and adhesion molecules to activate CAR T cells. Flow cytometry showed that most CLL cells expressed co-stimulatory and adhesion molecules at low levels; we hypothesized that up-regulating these molecules would enhance CAR T cell targeting of CLL cells. CLL cells were activated with CD40L and IL-4, which increased expression of CD54, CD58, CD80, and CD86. Stimulating CAR T cells with activated CLL cells enhanced CAR T cell proliferation and induced cell conjugate formation, indicating cell activation. Therefore, improving CLL stimulatory capacity can rescue T cell dysfunctions. To assess whether IL-2 addition and CD40 ligation were synergistic, we combined the two assays; however, we saw no additional improvement over IL-2 addition alone, suggesting that the two interventions may act upon the same pathway. Importantly, we also showed that rescue of CAR T cell function via IL-2 addition or CD40 ligation was not CAR-specific, as we observed the functional defects and subsequent rescue with both a ROR1-targeting CAR and the gold standard CD19-targeting CAR. Conclusions: Together, these data show that CAR T cell "defects" in CLL are actually insufficient activation, and improving the stimulatory capacity of CLL cells may enable better clinical responses. Further, this effect is not CAR-specific and these results may therefore be broadly applicable to multiple therapies for this disease. Disclosures Melenhorst: IASO Biotherapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kite Pharma: Research Funding; Novartis: Other: Speaker, Research Funding; Johnson & Johnson: Consultancy, Other: Speaker; Simcere of America: Consultancy; Poseida Therapeutics: Consultancy.

scholarly journals Factors associated with outcomes after a second CD19-targeted CAR T-cell infusion for refractory B cell malignancies

Blood ◽  
2020 ◽  
Author(s):  
Jordan Gauthier ◽  
Evandro D. Bezerra ◽  
Alexandre V. Hirayama ◽  
Salvatore Fiorenza ◽  
Alyssa Sheih ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Severe Toxicity ◽  
B Cell Malignancies ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Grade 3

CD19-targeted chimeric antigen receptor-engineered (CD19 CAR) T cell therapy has shown significant efficacy for relapsed or refractory (R/R) B-cell malignancies. Yet CD19 CAR T cells fail to induce durable responses in most patients. Second infusions of CD19 CAR T cells (CART2) have been considered as a possible approach to improve outcomes. We analyzed data from 44 patients with R/R B-cell malignancies (ALL, n=14; CLL, n=9; NHL, n=21) who received CART2 on a phase 1/2 trial at our institution. Despite a CART2 dose increase in 82% of patients, we observed a low incidence of severe toxicity after CART2 (grade ≥3 CRS, 9%; grade ≥3 neurotoxicity, 11%). After CART2, CR was achieved in 22% of CLL, 19% of NHL, and 21% of ALL patients. The median durations of response after CART2 in CLL, NHL, and ALL patients were 33, 6, and 4 months, respectively. Addition of fludarabine to cyclophosphamide-based lymphodepletion before CART1 and an increase in the CART2 dose compared to CART1 were independently associated with higher overall response rates and longer progression-free survival after CART2. We observed durable CAR T-cell persistence after CART2 in patients who received Cy-Flu lymphodepletion before CART1 and a higher CART2 compared to CART1 cell dose. The identification of two modifiable pre-treatment factors independently associated with better outcomes after CART2 suggests strategies to improve in vivo CAR T-cell kinetics and responses after repeat CAR T-cell infusions, and has implications for the design of trials of novel CAR T-cell products after failure of prior CAR T-cell immunotherapies.

Therapy of B Cell Malignancies with CD19-Specific Chimeric Antigen Receptor-Modified T Cells of Defined Subset Composition

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 384-384 ◽  
Author(s):  
Cameron J Turtle ◽  
Daniel Sommermeyer ◽  
Carolina Berger ◽  
Michael Hudecek ◽  
David M Shank ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cd4 T Cells ◽  
Research Funding ◽  
T Cell Subsets ◽  
B Cell Malignancies ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T

Abstract BACKGROUND: The adoptive transfer of CD19-specific chimeric antigen receptor-modified (CD19 CAR) T cells is a promising strategy for treating patients with CD19+ B cell acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), and non-Hodgkin lymphoma (NHL). Dramatic responses have been observed in a subset of patients receiving CD19 CAR T cell therapy, and prior studies suggest that persistence of transferred T cells may correlate with the extent of tumor regression. The use of unselected T cells to prepare CAR T cells results in variation in the phenotypic composition of the infused product in individual patients, making it difficult to determine whether particular T cell subsets contribute to efficacy and/or toxicity. Studies in our lab demonstrated that genetically modified effector T cells derived from purified T cell subsets differ in the capacity to persist in vivo after adoptive transfer, and that a combination of CAR-modified CD8+ central memory (TCM) and CD4+ T cells provides optimal antitumor activity in tumor xenograft models. Based on these data, we designed the first clinical trial in which patients with CD19+ B cell malignancies receive CD19 CAR T cells comprised of a defined composition of CD8+ TCM and CD4+T cells engineered to express a CD19 CAR. METHODS: Patients with relapsed or refractory CD19+ ALL, CLL or NHL are eligible for this phase I/II study. CD8+ TCM and CD4+ T cells were separately enriched by immunomagnetic selection from a leukapheresis product from each patient, and cryopreserved. The CD8+ TCM and CD4+ T cells were stimulated in independent cultures with anti-CD3/anti-CD28 paramagnetic beads, and transduced with a lentivirus encoding the murine FMC63 anti-CD19 scFv, 4-1BB and CD3 zeta signaling domains. After in vitro expansion, the cell product for infusion was formulated in a 1:1 ratio of CD4+:CD8+ CAR+ T cells. A truncated non-functional human epidermal growth factor receptor (EGFRt) encoded in the transgene cassette allowed identification of transgene-expressing T cells by flow cytometry. Lymphodepleting chemotherapy was administered followed by infusion of EGFRt+ CAR T cells at one of three dose levels (2 x 105 EGFRt+ cells/kg, 2 x 106 EGFRt+ cells/kg, 2 x 107 EGFRt+cells/kg). RESULTS: Twenty patients with relapsed or refractory ALL (n = 9), NHL (n = 10) or CLL (n = 1), including those who failed prior autologous (n = 4) or allogeneic (n = 4) stem cell transplant have been treated on the trial. Fifteen of 20 treated patients received a product that conformed to the prescribed CD8+ T­CM:CD4 composition. Five patients received a product manufactured using a modified strategy either due to low blood lymphocyte counts (n = 3) or due to failure to propagate T cells in culture (n = 2). CD8+ TCM and CD4+ T cells have been isolated from 12 additional patients and cryopreserved for therapy. Patients have been treated at all three dose levels without acute infusional toxicity. Severe cytokine release syndrome (sCRS) consisting of fever, hypotension, and reversible neurotoxicity associated with elevated serum IFN-γ and IL-6 was only observed in ALL patients with a high tumor burden. One ALL patient treated at the highest cell dose died of complications associated with sCRS. None of the NHL patients had sCRS. Of patients who are >6 weeks after CD19 CAR T cell therapy, best responses included complete (n=1) or partial (n=5) remission in 6/9 patients with NHL and complete remission in 5/7 patients with ALL. Both CD4+ and CD8+ CAR-T cells expanded in vivo and could be detected in blood, marrow and CSF. The peak level and duration of persistence of both CD4+ and CD8+ EGFRt+ T cells were associated with clinical response. TCRBV gene sequencing of flow sorted CD4+ and CD8+ EGFRt+CAR T cells from 2 patients showed that proliferating CAR T cells were polyclonal. A subset of NHL patients in whom CAR T cells became undetectable developed a T cell immune response to sequences in the murine CD19-specific scFv component of the CAR transgene. CONCLUSION: Adoptive immunotherapy with CD19 CAR T cells of defined subset composition is feasible and safe in a majority of heavily pretreated patients with refractory B cell malignancies and has potent anti-tumor activity. Persistence of CAR-T cells may be limited in some patients by transgene product immunogenicity. Data from this ongoing clinical trial will be updated at the meeting. Disclosures Turtle: Juno Therapeutics: Research Funding. Berger:Juno Therapeutics: Patents & Royalties. Hudecek:Juno Therapeutics: Patents & Royalties. Jensen:Juno: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Riddell:Juno Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Maloney:Juno Therapeutics: Research Funding.

scholarly journals CD229 CAR T Cell Therapy for the Treatment of Relapsed B Cell Lymphoma

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2800-2800
Author(s):  
Michael Olson ◽  
Tim Luetkens ◽  
Fiorella Iglesias ◽  
Sabarinath Radhakrishnan ◽  
Jennie Y. Law ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

Abstract B cell lymphoma is the most common hematologic malignancy in the United States. Although treatment options have greatly improved in the past several decades, outcomes for patients with relapsed B cell lymphoma remain poor. Chimeric antigen receptor (CAR) T cells have recently entered the clinic with promise to address the gap in effective therapies for patients relapsed B cell lymphoma. However, antigen loss and poor CAR T cell persistence has been shown to drive resistance to the widely approved CD19-targeted CAR in some patients, demonstrating the need for additional therapies. Here, we demonstrate CD229-targeted CAR T cell therapy as a promising option for the treatment of relapsed B cell lymphoma, addressing an important group of patients with typically poor outcomes. CD229 is an immune-modulating receptor expressed on the surface of B cells that we recently found to be highly expressed in the plasma cell neoplasm multiple myeloma (Radhakrishnan et al. 2020). We utilized semi-quantitative PCR and flow cytometry to assess whether CD229 is also expressed on malignant B cells earlier in development as found in B cell lymphoma. Expression analysis revealed the presence of CD229 in a panel of 11 B cell lymphoma cell lines and 45 primary B cell lymphoma samples comprising several subsets of disease including aggressive B cell lymphomas such as diffuse large B cell lymphoma (DLBCL), mantle cell lymphoma (MCL) and Burkitt lymphoma as well as indolent subtypes of B cell lymphoma including chronic lymphoblastic leukemia (CLL) and follicular lymphoma. Of note, CD229 was found to be overexpressed on primary B cell lymphoma cells when compared to autologous normal B cells. Given the high levels of CD229 expression throughout all B cell lymphoma subtypes analyzed, we generated CD229 CAR T cells in order to determine whether CAR T cell therapy is an effective way to target CD229 expressing B cell lymphoma cells. CD229 CAR T cells exhibited robust cytotoxicity when cocultured with B cell lymphoma cell lines and primary samples characterized by significant production of TH1 cytokines IL-2, TNF and IFNγ and rapid loss of B cell lymphoma cell viability when compared to control CAR T cells lacking an antigen binding scFv domain (∆scFv CAR T cells). In vivo analysis revealed effective tumor control in NSG mice carrying B cell lymphoma cell lines JeKo-1 (MCL) and DB (DLBCL) when treated with CD229 CAR T cells versus ∆scFv CAR T cells. Finally, we sought to determine the efficacy of CD229 CAR T cells in the context of CD19 CAR T cell therapy relapse. Here, a 71-year-old patient with CLL had an initial response when treated with CD19 CAR T cells but quickly relapsed only 2 months after treatment. Malignant cells from the CLL patient retained CD229 expression as identified by flow cytometry and an ex vivo coculture with CD229 CAR T cells revealed robust killing of CLL cells by CD229 CAR T cells. Transfer of antigen from target cell to CAR T cell by trogocytosis was recently suggested to drive relapse following CAR T cell therapy by decreasing antigen on tumor cells and promoting CAR T cell fratricide (Hamieh et al. 2019). We cocultured CD19 and CD229 CAR T cells with primary CLL cells and assessed CD19 and CD229 expression as well as CAR T cell viability by flow cytometry. In contrast with CD19 CAR T cells, CD229 CARs did not strip their target antigen from the surface of CLL cells. The transfer of CD19 from CLL cells to CD19 CAR T cells resulted in poor CAR T cell viability while CD229 CAR T cell viability remained high following coculture. In summary, we demonstrate that CD229 is a promising therapeutic target in B cell lymphoma due to its high levels of expression throughout many subtypes of disease. CD229 CAR T cells effectively kill B cell lymphoma cells in vitro and control growth of aggressive B cell lymphomas in vivo. Finally, CD229 CAR T cells are effective against primary CLL cells from patients that have relapsed from CD19 CAR T cell therapy and do no exhibit antigen loss by trogocytosis. Taken together, these data suggest that CD229 CAR T cell therapy may be a promising option to address the poor outcomes for patients with relapsed B cell lymphoma. Disclosures No relevant conflicts of interest to declare.

scholarly journals A Phase 1 Study with Point-of-Care Manufacturing of Dual Targeted, Tandem Anti-CD19, Anti-CD20 Chimeric Antigen Receptor Modified T (CAR-T) Cells for Relapsed, Refractory, Non-Hodgkin Lymphoma

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4193-4193 ◽  
Author(s):  
Nirav N Shah ◽  
Fenlu Zhu ◽  
Carolyn Taylor ◽  
Dina Schneider ◽  
Winfried Krueger ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Research Funding ◽  
Phase 1 ◽  
Third Party ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Equity Ownership

Abstract Background: CAR-T cell therapy directed against the CD19 antigen is a breakthrough treatment for patients (pts) with relapsed/refractory (R/R) B-cell NHL. Despite impressive outcomes, not all pts respond and many that respond still relapse. Affordability and accessibility are further considerations that limit current commercial models of CAR-T products. Commercial CAR-T manufacturing is complex, time consuming, and expensive with a supply chain starting at the treating center with apheresis of mononuclear cells, cryopreservation, and shipping to and from a centralized third-party manufacturing site. We addressed these limitations in a Phase 1 clinical trial evaluating a first-in-human bispecific tandem CAR-T cell directed against both CD19 and CD20 (CAR-20.19-T) antigens for pts with R/R B-cell NHL. Through dual targeting we hope to improve response rates and durability of response while limiting antigen escape. We eliminated third party shipping logistics utilizing the CliniMACS Prodigy, a compact tabletop device that allows for automated manufacturing of CAR-T cells within a GMP compliant environment within the hospital. Most materials and reagents used to produce the CAR-T cell product were single-sourced from the device manufacturer. Methods: Phase 1 (NCT03019055), single center, dose escalation + expansion study to demonstrate feasibility and safety of locally manufactured second generation 41BB + CD3z CAR-20.19-T cells via the CliniMACS Prodigy. Feasibility was measured by ability to generate a target CAR-20.19-T cell dose for a minimum of 75% of subjects. Safety was assessed by the presence of dose limiting toxicities (DLTs) through 28 days post-infusion. Dose was escalated in a 3+3 fashion with a starting dose of 2.5 x 10^5 cells/kg, a target DLT rate <33%, and a goal treatment dose of 2.5 x 10^6 cells/kg. Adults with R/R Diffuse Large B-cell Lymphoma (DLBCL), Follicular Lymphoma (FL), Mantle Cell Lymphoma (MCL) or Chronic Lymphocytic Leukemia (CLL) were eligible. CAR-T production was set for a 14-day manufacturing process. Day 8 in-process testing was performed to ensure quality and suitability of CAR-T cells for a potential fresh infusion. On Day 10, pts eligible for a fresh CAR-T infusion initiated lymphodepletion (LDP) chemotherapy with fludarabine 30 mg/m2 x 3 days and cyclophosphamide 500 mg/m2 x 1 day, and cells were administered after harvest on Day 14. Pts ineligible for fresh infusion received cryopreserved product and LDP was delayed accordingly. Results: 6 pts have been enrolled and treated with CAR-20.19-T cells: 3 pts at 2.5 x 10^5 cells/kg and 3 pts at 7.5 x 10^5 cells/kg. Median age was 53 years (48-62). Underlying disease was MCL in 3 pts, DLBCL in 2 pts, and CLL in 1 patient. Baseline data and prior treatments are listed in Table 1. CAR-T production was successful in all runs and all pts received their target dose. Three pts received fresh CAR-T cells and 3 pts received CAR-T cells after cryopreservation. To date there are no DLTs to report. No cases of Grade 3/4 cytokine release syndrome (CRS) or neurotoxicity (NTX) were observed. One patient had Grade 2 CRS and Grade 2 NTX requiring intervention. The other had self-limited Grade 1 CRS and Grade 1 NTX. Median time to development of CRS was Day +11 post-infusion. All pts had neutrophil recovery (ANC>0.5 K/µL) by Day 28. Response at Day 28 (Table 2) is as follows: 2/6 pts achieved a complete response (CR), 2/6 achieved a partial response (PR), and 2/6 had progressive disease (PD). One subject with a PR subsequently progressed at Day 90. The 3 pts who did progress all underwent a repeat biopsy, and all retained either CD19 or CD20 positivity. Pts are currently being enrolled at the target dose (2.5 x 10^6 cells/kg) and updated results will be provided at ASH. Conclusions: Dual targeted anti-CD19 and anti-CD20 CAR-T cells were successfully produced for all pts demonstrating the feasibility of a point-of-care manufacturing process via the CliniMACS Prodigy device. With no DLTs or Grade 3-4 CRS or NTX to report, and 2/6 heavily pre-treated pts remaining in CR at 3 and 9 months respectively our approach represents a feasible and promising alternative to existing CAR-T models and costs. Down-regulation of both target antigens was not identified in any patient following CAR-T infusion, and in-process studies suggest that a shorter manufacturing timeline is appropriate for future trials (10 days). Disclosures Shah: Juno Pharmaceuticals: Honoraria; Lentigen Technology: Research Funding; Oncosec: Equity Ownership; Miltenyi: Other: Travel funding, Research Funding; Geron: Equity Ownership; Exelexis: Equity Ownership. Zhu:Lentigen Technology Inc., A Miltenyi Biotec Company: Research Funding. Schneider:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Krueger:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Worden:Lentigen Technology Inc., A Miltenyi Biotec Company: Employment. Hamadani:Sanofi Genzyme: Research Funding, Speakers Bureau; Merck: Research Funding; Janssen: Consultancy; MedImmune: Consultancy, Research Funding; Cellerant: Consultancy; Celgene Corporation: Consultancy; Takeda: Research Funding; Ostuka: Research Funding; ADC Therapeutics: Research Funding. Johnson:Miltenyi: Research Funding. Dropulic:Lentigen, A Miltenyi Biotec company: Employment. Orentas:Lentigen Technology Inc., A Miltenyi Biotec Company: Other: Prior Employment. Hari:Takeda: Consultancy, Honoraria, Research Funding; Janssen: Honoraria; Kite Pharma: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Spectrum: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Amgen Inc.: Research Funding; Sanofi: Honoraria, Research Funding.

scholarly journals Phase 1 Study of CD19/CD22 Bispecific Chimeric Antigen Receptor (CAR) Therapy in Children and Young Adults with B Cell Acute Lymphoblastic Leukemia (ALL)

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 898-898 ◽  
Author(s):  
Liora M Schultz ◽  
Kara L. Davis ◽  
Christina Baggott ◽  
Christie Chaudry ◽  
Anne Cunniffe Marcy ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Research Funding ◽  
Disease Burden ◽  
Pediatric Patients ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Peak Car

Abstract Chimeric Antigen Receptor (CAR) therapy targeting CD19 achieves complete remission (CR) rates of 70%-90% in relapsed/refractory B-ALL. Relapse due to loss of the CD19 targeted epitope presents a therapeutic challenge as evidenced by the largest global pediatric CD19-CAR experience which showed 15 of 16 relapses to be explained by CD19 downregulation (Maude et al, NEJM 2018). Alternatively targeting CD22 using CD22-CAR therapy has demonstrated a CR rate of approximately 70% in both CD19+ and CD19- B-ALL, however relapse due to CD22 downregulation limits the curative potential of singularly-targeting CD22 (Fry et al, Nat Med. 2018). We hypothesized that simultaneous targeting of CD19 and CD22 via a bispecific CAR-T cell would be a safe and tolerable treatment strategy in relapsed/refractory B-cell ALL and address immune evasion. Here, we report the first clinical experience in pediatric patients using bispecific CD19-CD22 CAR T cells. We describe a single institution phase I dose escalation study in pediatric patients with relapsed or refractory B cell ALL. We utilized lentiviral transduction of a bivalent CAR construct incorporating the fmc63 CD19 and m971 CD22 single chain variable fragments (scFvs) used in clinically tested CAR constructs and a 41BB costimulatory endodomain (Fry et al, Nat Med. 2018). Our primary objectives are feasibility of production of this bivalent CAR and safety at 3 dose escalation levels (1x106, 3x106 and 1x107 CAR T cells/kg). Clinical response assessment is evaluated as a secondary aim. All patients described received lymphodepletion with fludarabine (25mg/m2 x 3 days) and cyclophosphamide (900mg/m2 x 1) followed by fresh or cryopreserved CAR T cell infusion after a 7-9 day production time. Patients were prospectively monitored at predefined intervals for disease response and correlative assessments. Four pediatric patients with precursor-B ALL, age 2-17, have been enrolled and treated with CD19/CD22 bispecific CAR T cells at dose level 1 (1x106) [Table 1]. Three patients entered CAR therapy with low disease burden detected by minimal residual disease (MRD) alone and 1 patient initiated therapy with 12% bone marrow blasts. All patients were CNS1 at time of treatment. The toxicity profile mirrored that of the singular CD19 and CD22 CAR experience with 3 patients experiencing reversible CRS (2 Grade I, 1 Grade II), onset day 3-8, and 2 patients experiencing grade I neurotoxicity, onset day 3-9. In our cohort, we experienced lower grade toxicities than previously reported, likely due to a mean lower disease burden. Only 1 patient with CRS met criteria for tocilizumab and this patient was the singular study patient treated with higher burden disease. Neurotoxicity was managed with supportive care and fully reversible. Peripheral blood flow cytometry analysis detects circulating CAR by day 6 in all patients and demonstrates peak CAR expansion between day 6-10. Peak CAR T expansion reached levels of 10-25% of total T cells with inter-patient variability in CD4 and CD8 predominance, favoring CD8 expansion in 3 of 4 patients. Clinical symptoms and inflammatory markers expectedly correlate with peak CAR expansion. Four of 4 patients achieved complete remission (CR) at day 28 post-CD19/CD22 bispecific CAR therapy. Three of 4 patients demonstrated MRD- remissions by flow cytometry and of these, next generation sequencing (NGS) was negative where available (N=2). Multi-parametric CyTOF studies permitting CAR T cell phenotyping in conjunction with single cell TCR tracking, proteomics, epigenomics and cytokine profiling are ongoing and will be used to further characterize persisting CAR T cells and define inter-product and inter-patient variability. In this phase I study, we demonstrate safety and tolerability of this bispecific CD19/CD22 CAR at a dose of 1x106 CAR T cells/kg in pediatric patients with relapsed/refractory B cell ALL. The CD19/22-bispecific CAR mediated antileukemic activity in 100% of patients studied thus far. Long-term follow up and further accrual will be required to inform the effect of bispecific CAR targeting on surface antigen remodeling. Disclosures Muffly: Adaptive Biotechnologies: Research Funding; Shire Pharmaceuticals: Research Funding. Miklos:Genentech: Research Funding; Kite - Gilead: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Pharmacyclics - Abbot: Consultancy, Research Funding; Adaptive Biotechnologies: Consultancy, Research Funding; Novartis: Consultancy, Research Funding.

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.

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