scholarly journals High Effectiveness and Safety of Anti-CD7 CAR T-Cell Therapy in Treating Relapsed or Refractory (R/R) T-Cell Acute Lymphoblastic Leukemia (T-ALL)

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 473-473
Author(s):  
Junfang Yang ◽  
Xian Zhang ◽  
Ying Liu ◽  
Xiao Yang ◽  
Hui Wang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
High Risk ◽  
Disease Progression ◽  
Single Chain ◽  
Hematopoietic Stem ◽  
Rapid Disease Progression ◽  
Car T ◽  
Heavily Pretreated ◽  
Post Infusion

Abstract Background Compared with the substantial efficacy of chimeric antigen receptor T-cell (CAR-T) therapy that has achieved in B-ALL, whether CAR-T therapy is effective and safe for patients with T-ALL is still being explored in early stage clinical trials. Here, we present outcomes from our phase 1 clinical trial of CD7-targeting CAR-T (CD7CAR) cells therapy for R/R T-ALL (NCT04572308). Methods Peripheral blood (PB) mononuclear cells were obtained by leukapheresis. T cells were separated and transduced with lentivirus. The second-generation CD7CAR is composed of an anti-CD7 single-chain antibody, a IgG4 hinge region, a CD28TM transmembrane domain, an intracellular co-stimulatory domain of 4-1BB and CD3ζ, and the truncated EGFR protein linked by T2A. All patients received intravenous fludarabine (30 mg/m 2/d) and cyclophosphamide (300 mg/m 2/d) for 3 days prior to CD7CAR infusion. Results Seventeen R/R T-ALL patients were enrolled between December 2020 and June 2021. Characteristics of patients are shown in Table 1. Data from 14 patients with a median age of 17 years (range: 3-42 years) were available for evaluation. The rest 3 patients were withdrawn from study within 14 days due to rapid disease progression. High-risk subtype patients enrolled including 1 with Ph-positive T-ALL and 3 with early T-cell precursor (ETP)-ALL. Seven of the 14 patients also had high-risk genotypes, namely SIL-TAL1, EZH2, TP53, RUNX1, BCR-ABL, JAK1 and JAK3. At enrollment, the median percentage of bone marrow (BM) blasts was 11.53% (range: 0.18%-65.03%), and 5 of 14 patients had extramedullary involvements, including optic nerve involvement (N=2), central nervous system leukemia (N=3), diffuse extramedullary involvements (N=2), and bulky lymph nodes in the neck (N=1). Patients were heavily pretreated with a median of 5 prior lines of therapies (range: 3-8 lines) and three relapsed from prior allogeneic hematopoietic stem cell transplantation (allo-HSCT). CD7CAR-T cells were 100% successfully manufactured with a transfection efficiency of 93.8% (range: 59.6%-99.9%). Twelve of 14 participants received bridging chemotherapy. A single dose of CD7CAR-T cells was infused to patients, with 2 receiving a low-dose (0.5x10 5 cells/kg), 11 receiving a medium dose (1-1.5x10 6 cells/kg) and 1 receiving a high-dose (2x10 6 cells/kg). By the data cutoff date (July 12, 2021), the median follow-up time was 105 days (range: 32-206 days, Fig.1A). By day 28 post infusion, 92.9% (13/14) of patients achieved complete remission (CR, N=4) or CR with incomplete hematological recovery (CRi, N=9) in their BM, with all 13 patients achieving minimal residual disease (MRD) negative CR/CRi. Additionally, 4/5 patients with extramedullary involvement also achieved extramedullary remission at a median of day 32 (range: 28-90 days) post infusion. Consolidation allo-HSCT was permitted at the treatment physician's discretion and the patient's preference. A total of 11/14 patients were bridged to consolidation allo-HSCT at a median of 57 days post CD7CAR infusion, of which 9 patients have remained MRD-negative CR/CRi. One patient who had allo-HSCT prior to CD7CAR infusion died following a second haplo-HSCT due to acute graft-versus-host disease. Of the other 3 patients who were not bridged to allo-HSCT, 1 patient relapsed on day 28 due to rapid disease progression after initial CRi on day 14. Thirteen of 14 patients experienced mild CRS (Grade ≤2). One patient had Grade 3 CRS. The median time to onset of CRS was 1 day (range: 0-11 days), with a median duration of 14 days (range: 3-25 days). Neurotoxicity (Grade 1) occurred in only 1 patient. After infusion, the median peak of CAR-T copy number was 2.38 ×10 5copies/µg DNA (range: 0.2-6.67 ×10 5 copies/µg DNA), which occurred on day 20 (range: 10-42 days, Fig.1B). Importantly, CD7CAR persisted well in PB at a median of 52.5 days (range:20-120 days) at last evaluation regardless of transplantation status. Maximum proportion of CD7CAR-T cells proliferation reached 84.95% by flow cytometry (Fig.1C). Conclusions Our results demonstrate that CD7CAR therapy is safe and highly effective in treating patients with heavily pretreated R/R T-ALL, including those with extramedullary involvements, a history of prior allo-HSCT or with high-risk subtypes. More patients and a longer observation time are needed to further evaluate the potential beneficial advantages and side effects of CD7CAR therapy for T-ALL patients. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

CD70-specific CAR T-cells have potent activity against Acute Myeloid Leukemia (AML) without HSC toxicity

Blood ◽  
2021 ◽  
Author(s):  
Tim Sauer ◽  
Kathan Parikh ◽  
Sandhya Sharma ◽  
Bilal Omer ◽  
David Nikolov Sedloev ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
T Cell ◽  
Myeloid Leukemia ◽  
Target Antigen ◽  
Single Chain ◽  
Hematopoietic Stem ◽  
Car T Cells ◽  
Car T ◽  
Acute Myeloid

The prognosis of patients with acute myeloid leukemia (AML) remains dismal highlighting the need for novel innovative treatment strategies. The application of chimeric antigen receptor (CAR) T-cell therapy to AML patients has been limited in particular by the lack of a tumor-specific target antigen. CD70 is a promising antigen to target AML as it is expressed on the majority of leukemic blasts, whereas little or no expression is detectable in normal bone marrow samples. To target CD70 on AML cells, we generated a panel of CD70-CARs that contained a common single chain variable fragment (scFv) for antigen detection but differed in size and flexibility of the extracellular spacer, and in the transmembrane and the co-stimulatory domains. These CD70scFv CARs were compared with a CAR construct that contained the human CD27, the ligand of CD70 fused to the CD3z chain (CD27z). The structural composition of the CAR strongly influenced expression levels, viability, expansion and cytotoxic capacities of CD70scFv CAR T-cells, but the CD27z-CAR T-cells demonstrated superior proliferation and anti-tumor activity in vitro and in vivo, compared to all CD70scFv-CARs. While CD70-CAR T-cells recognized activated virus-specific T-cells (VSTs) that expressed CD70, they did not prevent colony formation by normal hematopoietic stem cells (HSCs). Thus, CD70-targeted immunotherapy is a promising new treatment strategy for patients with CD70-positive AML that does not affect normal hematopoiesis but will require monitoring of virus-specific T-cell responses.

scholarly journals B Cell Maturation Antigen-Specific CAR T Cells for Relapsed or Refractory Multiple Myeloma: A Meta-Analysis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3113-3113 ◽  
Author(s):  
Nico Gagelmann ◽  
Francis Ayuketang Ayuk ◽  
Djordje Atanackovic ◽  
Nicolaus Kroeger
Keyword(s):  
T Cells ◽  
T Cell ◽  
High Risk ◽  
Research Funding ◽  
Response Rates ◽  
Overall Response ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Background Cellular immunotherapies represent an enormously promising strategy for relapsed/refractory multiple myeloma (RRMM). Chimeric antigen receptor (CAR) T cells targeting B cell maturation antigen (BCMA) have shown impressive results in early-phase clinical studies. Here, we summarize the current body of evidence on the role of anti-BCMA CAR T cell therapy for RRMM. Methods We performed a systematic literature review to identify all publicly available prospective studies. We searched Medline, Cochrane trials registry, and www.clinicaltrials.gov. To include the most recent evidence, meeting abstracts from international hematology congresses were added. A conventional meta-analysis was conducted using meta and metafor packages in R statistical software. Pooled event rates and 95% confidence intervals (CIs) were calculated using the inverse variance method within a random-effects framework. Main efficacy outcomes were overall response, complete response (CR), and minimal residual disease (MRD). Furthermore, relapse rates, progression-free survival, and overall survival were evaluated. In terms of safety, outcomes were cytokine release syndrome (CRS), neurotoxicity, and hematologic toxic effects. Results Fifteen studies comprising a total of 285 patients with heavily pretreated RRMM were included in quantitative analyses. Patients received a median of seven prior treatment lines (such as proteasome inhibitors, immunomodulatory drugs, monoclonal antibodies, stem cell transplantation) which included autologous stem cell transplantation in 90% of patients. The median age of patients was 59 years and median follow-up duration ranged from 1.1 to 11.3 months. Most studies used 4-1BB (or CD137), a member of the TNF receptor superfamily, as an activation-induced T-cell costimulatory molecule. Most studies used fludarabine and cyclophosphamide for lymphodepletion while one study used busulfan and cyclophosphamide and one study used cyclophosphamide only. Most studies used the former Lee criteria for CRS grading. Anti-BCMA CAR T cells resulted in a pooled overall response of 82% (95% CI, 74-88%). The pooled proportion of CR in all evaluable patients was 36% (95% CI, 24-50%). Within responders, the pooled proportion of MRD negativity was 77% (95% CI, 67-85%). Higher dose levels of infused CAR+ cells were associated with higher overall response rates resulting in a pooled proportion of 88% (95% CI, 78-94%). In addition, peak CAR T cell expansion appeared to be associated with responses.The presence of high-risk cytogenetics appeared to be associated with lower overall response rates resulting in a pooled proportion of 68% (95% CI, 47-83%). The presence of extramedullary disease at time of infusion did not influence outcome and was associated with similar response rates compared with RRMM patients who did not have extramedullary disease, resulting in a pooled proportion of 78% (95% CI, 47-93%). The pooled relapse rate of all responders was 45% (95% CI, 27-64%) and the median progression-free survival was 10 months. In terms of overall survival, pooled survival rates were 84% (95% CI, 60-95%) at last follow-up (median, 11 months). In terms of safety, the pooled proportion of CRS of any grade was 69% (95% CI, 51-83%). Notably, the pooled proportions of CRS grades 3-4 and neurotoxicity were 15% (95% CI, 10-23%) and 18% (95% CI, 10-31%). Peak CAR T cell expansion appeared to be more likely in the setting of more severe CRS in three studies. Most hematologic toxic effects of grade 3 or higher were neutropenia (85%), thrombocytopenia (70%), and leukopenia (60%). Conclusion Anti-BCMA CAR T cells showed high response rates, even in high-risk features such as high-risk cytogenetics and extramedullary disease at time of CAR T cell infusion. Toxicity was manageable across all early-phase studies. However, almost half of the patients who achieved a response eventually relapsed. Larger studies with longer follow-up evaluating the association of response and survival are needed. Disclosures Ayuk: Novartis: Honoraria, Other: Advisory Board, Research Funding. Kroeger:Medac: Honoraria; Sanofi-Aventis: Honoraria; Neovii: Honoraria, Research Funding; Riemser: Research Funding; JAZZ: Honoraria; Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; DKMS: Research Funding.

Siglec-6 is a novel target for CAR T-cell therapy in acute myeloid leukemia (AML)

Blood ◽  
2021 ◽  
Author(s):  
Hardikkumar Jetani ◽  
Almudena Navarro-Bailón ◽  
Marius Maucher ◽  
Silke Frenz ◽  
Christina Mathilde Verbruggen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
T Cell Therapy ◽  
Hematopoietic Stem ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T ◽  
Novel Target

Acute myeloid leukemia (AML) is attractive for the development of CAR T-cell immunotherapy because AML blasts are susceptible to T-cell-mediated elimination. Here, we introduce sialic-acid-binding immunoglobulin-like lectin (Siglec)-6 as a novel target for CAR T-cells in AML. We designed a Siglec-6-specific CAR with a targeting-domain derived from a human monoclonal antibody JML‑1. We found that Siglec-6 is prevalently expressed on AML cell lines and primary AML blasts, including the subpopulation of AML stem cells. Treatment with Siglec-6-CAR T-cells confers specific anti-leukemia reactivity that correlates with Siglec-6-expression in pre-clinical models, including induction of complete remission in a xenograft AML model in immunodeficient mice (NSG/U937). In addition, we confirmed Siglec-6-expression on transformed B-cells in chronic lymphocytic leukemia (CLL) and show specific anti-CLL-reactivity of Siglec-6-CAR T-cells in vitro. Of particular interest, we found that Siglec-6 is not detectable on normal hematopoietic stem and progenitor cells (HSC/P) and that treatment with Siglec-6-CAR T-cells does not affect their viability and lineage differentiation in colony-formation assays. These data suggest that Siglec-6-CAR T-cell therapy may be used to effectively treat AML without a need for subsequent allogeneic hematopoietic stem cell transplantation. In mature normal hematopoietic cells, we detected Siglec-6 in a proportion of memory (and naïve) B-cells and basophilic granulocytes, suggesting the potential for limited on-target/off-tumor reactivity. The lacking expression of Siglec-6 on normal HSC/P is a key differentiator from other Siglec-family members (e.g. Siglec-3=CD33) and other CAR target antigens, e.g. CD123, that are under investigation in AML and warrants the clinical investigation of Siglec-6-CAR T-cell therapy.

scholarly journals CAR T cells vs allogeneic HSCT for poor-risk ALL

Hematology ◽  
2020 ◽  
Vol 2020 (1) ◽  
pp. 501-507
Author(s):  
Caroline Diorio ◽  
Shannon L. Maude
Keyword(s):  
T Cells ◽  
High Risk ◽  
Survival Benefit ◽  
Lymphoblastic Leukemia ◽  
Hematopoietic Stem ◽  
Car T Cells ◽  
Poor Risk ◽  
Car T ◽  
First Remission ◽  
Very High

Abstract For subgroups of children with B-cell acute lymphoblastic leukemia (B-ALL) at very high risk of relapse, intensive multiagent chemotherapy has failed. Traditionally, the field has turned to allogeneic hematopoietic stem cell transplantation (HSCT) for patients with poor outcomes. While HSCT confers a survival benefit for several B-ALL populations, often HSCT becomes standard-of-care in subsets of de novo ALL with poor risk features despite limited or no data showing a survival benefit in these populations, yet the additive morbidity and mortality can be substantial. With the advent of targeted immunotherapies and the transformative impact of CD19-directed chimeric antigen receptor (CAR)–modified T cells on relapsed or refractory B-ALL, this approach is currently under investigation in frontline therapy for a subset of patients with poor-risk B-ALL: high-risk B-ALL with persistent minimal residual disease at the end of consolidation, which has been designated very high risk. Comparisons of these 2 approaches are fraught with issues, including single-arm trials, differing eligibility criteria, comparisons to historical control populations, and vastly different toxicity profiles. Nevertheless, much can be learned from available data and ongoing trials. We will review data for HSCT for pediatric B-ALL in first remission and the efficacy of CD19 CAR T-cell therapy in relapsed or refractory B-ALL, and we will discuss an ongoing international phase 2 clinical trial of CD19 CAR T cells for very-high-risk B-ALL in first remission.

A Novel and Highly Potent CAR T Cell Drug Product for Treatment of BCMA-Expressing Hematological Malignances

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3094-3094 ◽  
Author(s):  
Alena A. Chekmasova ◽  
Holly M. Horton ◽  
Tracy E. Garrett ◽  
John W. Evans ◽  
Johanna Griecci ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cell Lines ◽  
Drug Product ◽  
Single Chain ◽  
Employment Equity ◽  
Car T Cells ◽  
Car T ◽  
Equity Ownership

Abstract Recently, B cell maturation antigen (BCMA) expression has been proposed as a marker for identification of malignant plasma cells in patients with multiple myeloma (MM). Nearly all MM and some lymphoma tumor cells express BCMA, while normal tissue expression is restricted to plasma cells and a subset of mature B cells. Targeting BCMA maybe a therapeutic option for treatment of patients with MM and some lymphomas. We are developing a chimeric antigen receptor (CAR)-based therapy for the treatment of BCMA-expressing MM. Our anti-BCMA CAR consists of an extracellular single chain variable fragment (scFv) antigen recognition domain derived from an antibody specific to BCMA, fused to CD137 (4-1BB) co-stimulatory and CD3zeta chain signaling domains. Selection of our development candidate was based on the screening of four distinct anti-BCMA CARs (BCMA01-04) each comprised of unique single chain variable fragments. One candidate, BCMA02 (drug product name bb2121) was selected for further studies based on the robust frequency of CAR-positive cells, increased surface expression of the CAR molecule, and superior in vitro cytokine release and cytolytic activity against the MM cell lines. In addition to displaying specific activity against MM (U226-B1, RPMI-8226 and H929) and plasmacytoma (H929) cell lines, bb2121 was demonstrated to react to lymphoma cell lines, including Burkitt's (Raji, Daudi, Ramos), chronic lymphocytic leukemia (Mec-1), diffuse large B cell (Toledo), and a Mantle cell lymphoma (JeKo-1). Based on receptor density quantification, bb2121 can recognize tumor cells expressing less than 1000 BCMA molecules per cell. The in vivo pharmacology of bb2121 was studied in NSG mouse models of human MM and Burkitt's lymphoma. NSG mice were injected subcutaneously (SC) with 107 RPMI-8226 MM cells. After 18 days, mice received a single intravenous (IV) administration of vehicle or anti-CD19Δ (negative control, anti-CD19 CAR lacking signaling domain) or anti-BCMA CAR T cells, or repeated IV administration of bortezomib (Velcade®; 1 mg/kg twice weekly for 4 weeks). Bortezomib, which is a standard of care for MM, induced only transient reductions in tumor size and was associated with toxicity, as indicated by substantial weight loss during dosing. The vehicle and anti-CD19Δ CAR T cells failed to inhibit tumor growth. In contrast, treatment with bb2121 resulted in rapid and sustained elimination of the tumors, increased body weights, and 100% survival. Flow cytometry and immunohistochemical analysis of bb2121 T cells demonstrated trafficking of CAR+ T cells to the tumors (by Day 5) followed by significant expansion of anti-BCMA CAR+ T cells within the tumor and peripheral blood (Days 8-10), accompanied by tumor clearance and subsequent reductions in circulating CAR+ T cell numbers (Days 22-29). To further test the potency of bb2121, we used the CD19+ Daudi cell line, which has a low level of BCMA expression detectable by flow cytometry and receptor quantification analysis, but is negative by immunohistochemistry. NSG mice were injected IV with Daudi cells and allowed to accumulate a large systemic tumor burden before being treated with CAR+ T cells. Treatment with vehicle or anti-CD19Δ CAR T cells failed to prevent tumor growth. In contrast, anti-CD19 CAR T cells and anti-BCMA bb2121 demonstrated tumor clearance. Adoptive T cell immunotherapy approaches designed to modify a patient's own lymphocytes to target the BCMA antigen have clear indications as a possible therapy for MM and could be an alternative method for treatment of other chemotherapy-refractory B-cell malignancies. Based on these results, we will be initiating a phase I clinical trial of bb2121 for the treatment of patients with MM. Disclosures Chekmasova: bluebird bio, Inc: Employment, Equity Ownership. Horton:bluebird bio: Employment, Equity Ownership. Garrett:bluebird bio: Employment, Equity Ownership. Evans:bluebird bio, Inc: Employment, Equity Ownership. Griecci:bluebird bio, Inc: Employment, Equity Ownership. Hamel:bluebird bio: Employment, Equity Ownership. Latimer:bluebird bio: Employment, Equity Ownership. Seidel:bluebird bio, Inc: Employment, Equity Ownership. Ryu:bluebird bio, Inc: Employment, Equity Ownership. Kuczewski:bluebird bio: Employment, Equity Ownership. Horvath:bluebird bio: Employment, Equity Ownership. Friedman:bluebird bio: Employment, Equity Ownership. Morgan:bluebird bio: Employment, Equity Ownership.

Allogeneic T-Cells Expressing an Anti-CD19 Chimeric Antigen Receptor Cause Remissions of B-Cell Malignancies after Allogeneic Hematopoietic Stem Cell Transplantation without Causing Graft-Versus-Host Disease

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 99-99 ◽  
Author(s):  
Jennifer N Brudno ◽  
Robert Somerville ◽  
Victoria Shi ◽  
Jeremy J. Rose ◽  
David C. Halverson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
B Cell ◽  
B Cell Malignancies ◽  
Hematopoietic Stem ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Peak Blood

Introduction Progressive malignancy is the leading cause of death after allogeneic hematopoietic stem cell transplantation (alloHSCT). After alloHSCT, B-cell malignancies are often treated with infusions of unmanipulated donor lymphocytes (DLIs) from the transplant donor. DLIs are frequently not effective at eradicating malignancy, and DLIs often cause graft-versus-host disease (GVHD), which is a potentially lethal allogeneic immune response against normal recipient tissues. Methods We conducted a clinical trial of allogeneic T cells that were genetically engineered to express a chimeric antigen receptor (CAR) targeting the B-cell antigen CD19. The CAR was encoded by a gamma-retroviral vector and included a CD28 costimulatory domain. Patients with B-cell malignancies after alloHSCT received a single infusion of CAR T cells. No chemotherapy or other therapies were administered. The T cells were obtained from each recipient's alloHSCT donor. Findings Eight of 20 treated patients obtained remissions, including 6 complete remissions (CR) and 2 partial remissions. The response rate was highest for acute lymphoblastic leukemia with 4/5 patients obtaining minimal-residual-disease-negative CRs, but responses also occurred in chronic lymphocytic leukemia (CLL) and lymphoma. The longest ongoing CR is 30+ months in a patient with CLL. No patient developed new-onset acute GVHD after CAR T-cells were infused. Toxicities included fever, tachycardia, and hypotension. Median peak blood CAR T-cell levels were higher in patients who obtained remissions (39 CAR+ cells/mL) than in patients who did not obtain remissions (2 CAR+ cells/mL, P=0.001). Presence of endogenous normal or malignant blood B lymphocytes before CAR T-cell infusion was associated with higher post-infusion median blood CAR T-cell levels (P=0.04). Compared to patients who did not obtain a remission of their malignancies, patients obtaining remissions had a higher CD8:CD4 ratio of blood CAR+ T cells at the time of peak CAR T-cell levels (P=0.007). The mean percentage of CAR+CD8+ T cells expressing the programmed cell death-1 (PD-1) protein increased from 12% at the time of infusion to 82% at the time of peak blood CAR T-cell levels (P<0.0001). The mean percentage of CAR+CD4+ T cells expressing PD-1 increased from 32% at the time of infusion to 91% at the time of peak blood CAR T-cell levels (P<0.0001). Interpretation Infusion of allogeneic anti-CD19 CAR T cells is a promising approach for treating B-cell malignancies after alloHSCT. Our findings point toward a future in which antigen-specific T-cell therapies will be an important part of the field of allogeneic hematopoietic stem cell transplantation. Table. PatientNumber Malignancy Transplant type Total T cellsinfused/kg Anti-CD19CAR-expressingT cells infused/kg Malignancyresponseat last follow-up(interval from infusion to last follow-up in months) 1 CLL URD 10/10 HLA match 1x106 0.4x106 SD (3) 2 DLBCL Sibling 2x106 0.7x106 SD (1) 3 CLL Sibling 4x106 2.4x106 PD 4 DLBCL Sibling 4x106 2.2x106 SD (31+) 5 CLL URD 10/10 HLA match 1.5x106 1.0x106 CR (30+) 6 MCL Sibling 7x106 4.6x106 SD (3) 7 CLL URD 10/10 HLA match 1x106 0.7x106 PD 8 MCL Sibling 7x106 3.9x106 SD (24+) 9 MCL URD 10/10 HLA match 4x106 2.2x106 PR (3) 10 MCL Sibling 10x106 7.8x106 SD (2) 11 CLL URD 9/10 HLA match 5x106 3.1x106 PR (12+) 12 ALL Ph+ Sibling 7x106 5.2x106 MRD-negative CR (15+) 13 MCL Sibling 10x106 7.1x106 SD (9) 14 ALL Ph-neg Sibling 10x106 7.0x106 MRD-negative CR (5) 15 ALL Ph-neg Sibling 10x106 6.9x106 MRD-negative CR (3) 16 ALL Ph-neg Sibling 7x106 5.6x106 PD 17 DLBCL Sibling 10x106 8.2x106 CR (6+) 18 DLBCL Sibling 10x106 3.1x106 SD (2) 19 FL transformed to DLBCL URD 10/10 HLA match 5x106 4.3x106 PD 20 ALL Ph-neg URD 9/10 HLA match 5x106 4.2x106 MRD-negative CR (3+)^ CLL, chronic lymphocytic leukemia; ALL Ph+, Philadelphia chromosome positive acute lymphoblastic leukemia; ALL Ph-neg, Philadelphia chromosome negative acute lymphoblastic leukemia; MCL, mantle cell lymphoma; DLBCL, diffuse large B-cell lymphoma; FL, follicular lymphoma; Sibling, human leukocyte antigen-matched sibling donor; URD, unrelated donor; HLA, human leukocyte antigen; PD, progressive disease; SD, stable disease; PR, partial remission; CR, complete remission; MRD-negative, minimal residual disease negative. ^Patient 20 underwent a second alloHSCT 3.5 months after anti-CD19 CAR T-cell infusion while in MRD-negative CR. Disclosures Goy: Celgene: Consultancy, Research Funding, Speakers Bureau; Allos, Biogen Idec, Celgene, Genentech, and Millennium. Gilead: Speakers Bureau. Rosenberg:Kite Pharma: Other: CRADA between Surgery Branch-NCI and Kite Pharma.

Unicar: A Novel Modular Retargeting Platform Technology for CAR T Cells

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5549-5549 ◽  
Author(s):  
Marc Cartellieri ◽  
Simon Loff ◽  
Malte von Bonin ◽  
Elham P. Bejestani ◽  
Armin Ehninger ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Target Cell ◽  
Binding Domain ◽  
Single Chain ◽  
Chain Fragment ◽  
Cell Recruitment ◽  
Single Chain Fragment Variable ◽  
Car T ◽  
Single Chain Fragment

Abstract The adoptive transfer of T cells engineered with chimeric antigen receptors (CARs) is currently considered as a highly promising therapeutic option for treatment of otherwise incurable malignant diseases. CARs combine the cellular and humoral arm of the immune response by assembling a single-chain fragment variable (scFv) as binding moiety which provides the antigen-specificity and an activating immune receptor. It has been demonstrated both in vitro and in vivo, that CAR engrafted effector T cells mediate long-lasting anti-tumor responses. Despite encouraging clinical efficacy targeting CD19 in recent clinical trials, the appearance of potentially life-threatening adverse reactions and the lack of control mechanisms once initiated, prevent more widespread application of the CAR technology. To overcome limitations of conventional CAR T cells, a unique chimeric antigen receptor (UniCAR) technology was developed (Fig. 1) which allows precise control of CAR T cell reactivity, thus lowering the risk of side effects while preserving efficacy. Moreover, the UniCAR technology enables the retargeting of engrafted T cells against more than one antigen simultaneously or subsequently, thus reducing the risk for development of antigen-loss tumor variants under treatment. The UniCAR technology splits the signaling and antigen-binding aspects of conventional CAR into two individual components. T cells are engineered to express a universal CAR (UniCAR), which has specificity for a short peptide motif of 10 amino acids derived from a human nuclear protein. Thus, T cells engineered to express UniCAR remain inactivated after re-infusion, since the UniCAR target is not available for binding under physiological conditions. The ultimate antigen-specificity of the system is provided separately by targeting modules (TMs) comprising a binding domain e.g., a tumor-antigen specific scFv, fused to the nuclear antigen motif recognized by the UniCAR binding domain. Here we provide first in vitro and in vivo prove of concept for this new approach. Antigen-specific redirection of T cells armed with the universal CAR in the presence of different targeting modules against various antigens (CD33, CD123, CD19, CD20, PSCA, PSMA,) was effective at femtomolar concentrations of the targeting module both. Taken together, the modular nature of UniCAR technology will allow retargeting of autologous, patient-derived T cells to several antigens under controlled pharmacological conditions and has the potential to become a highly effective treatment option for late stage cancer patients with reduced risks for side effects. Figure 1. Schematic representation of T cell recruitment with the modular UniCAR system. The UniCAR T cell recruitment system consists of two separated units. The first unit is the UniCAR expressed on T cells with a single-chain fragment variable (scFv) specific for a short 10 aa long peptide motif. The intracellular signalling domain of the UniCAR contains a costimulatory domain derived from CD28 and the T cell receptor z chain. The second unit is a targeting molecule (TM) which consists of a scFv fused to the peptide epitope. The cross-linkage of T cell and target cell is mediated by interaction between the UniCAR binding domain on T cells and target cell binding TM. Figure 1. Schematic representation of T cell recruitment with the modular UniCAR system. / The UniCAR T cell recruitment system consists of two separated units. The first unit is the UniCAR expressed on T cells with a single-chain fragment variable (scFv) specific for a short 10 aa long peptide motif. The intracellular signalling domain of the UniCAR contains a costimulatory domain derived from CD28 and the T cell receptor z chain. The second unit is a targeting molecule (TM) which consists of a scFv fused to the peptide epitope. The cross-linkage of T cell and target cell is mediated by interaction between the UniCAR binding domain on T cells and target cell binding TM. Disclosures Cartellieri: Cellex Patient Treatment GmbH: Employment. Loff:GEMoaB Monoclonals GmbH: Employment. Ehninger:GEMoaB Monoclonals GmbH: Employment, Patents & Royalties: related to the UniTARG system. Ehninger:GEMoaB Monoclonals GmbH: Equity Ownership; Cellex Patient Treatment GmbH: Equity Ownership. Bachmann:GEMoaB Monoclonals GmbH: Equity Ownership, Patents & Royalties: related to the UniTARG system.

scholarly journals Decade-long remissions of leukemia sustained by the persistence of activated CD4+ CAR T-cells

2021 ◽  
Author(s):  
Jan Joseph Melenhorst ◽  
Gregory M Chen ◽  
Meng Wang ◽  
David . L Porter ◽  
Peng Gao ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymphocytic Leukemia ◽  
Late Time ◽  
Sustained Remission ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Post Infusion

The adoptive transfer of T lymphocytes reprogrammed to target tumor cells has demonstrated significant potential in various malignancies. However, little is known about the long-term potential and the clonal stability of the infused cells. Here, we studied the longest persisting CD19 redirected chimeric antigen receptor (CAR) T cells to date in two chronic lymphocytic leukemia (CLL) patients who achieved a complete remission in 2010. CAR T-cells were still detectable up to 10+ years post-infusion, with sustained remission in both patients. Surprisingly, a prominent, highly activated CD4+ population developed in both patients during the years post-infusion, dominating the CAR T-cell population at the late time points. This transition was reflected in the stabilization of the clonal make-up of CAR T-cells with a repertoire dominated by few clones. Single cell multi-omics profiling via Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-Seq) with TCR sequencing of CAR T-cells obtained 9.3 years post-infusion demonstrated that these long-persisting CD4+ CAR T-cells exhibited cytotoxic characteristics along with strong evidence of ongoing functional activation and proliferation. Our data provide novel insight into the CAR T-cell characteristics associated with long-term remission in leukemia.

scholarly journals An Off-the-Shelf™ Fratricide-Resistant CAR-T for the Treatment of T Cell Hematologic Malignancies

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 844-844
Author(s):  
Matt L Cooper ◽  
Jaebok Choi ◽  
Karl W. Staser ◽  
Julie Ritchey ◽  
Jessica Niswonger ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Targeted Therapies ◽  
Conflicts Of Interest ◽  
Cell Transplant ◽  
Single Chain ◽  
Car T Cells ◽  
Human T Cell ◽  
Car T ◽  
T Cell Malignancies

Abstract T cell malignancies represent a class of devastating hematologic cancers with high rates of relapse and mortality in both children and adults for which there are currently no effective or targeted therapies. Despite intensive multi-agent chemotherapy regimens, fewer than 50% of adults and 75% of children with T-ALL survive beyond five years. For those who relapse after initial therapy, salvage chemotherapy regimens induce remissions in 20-40% of cases. Allogeneic stem cell transplant, with its associated risks and toxicities, is the only curative therapy. T cells engineered to express a chimeric antigen receptor (CAR) are a promising cancer immunotherapy. Such targeted therapies have shown great potential for inducing both remissions and even long-term relapse-free survival in patients with B cell leukemia and lymphoma7-9. Thus, a targeted therapy against T cell malignancies represents a significant unmet medical need. However, several challenges have limited the clinical development of CAR-T cells against T cell malignancies. First, the shared expression of target antigens between T effector cells and T cell malignancies results in fratricide, or self-killing, of CAR-T cells. Second, harvesting adequate numbers of autologous T cells, without contamination by malignant cells is, at best, technically challenging and prohibitively expensive. Third, the use of genetically modified CAR-T cells from allogeneic donors may result in life-threatening graft-vs.-host disease (GvHD) when infused into immune-compromised HLA-matched or mismatched recipients. We hypothesized that deletion of CD7 and the T cell receptor alpha chain (TRAC) using CRISPR/Cas9 in CAR-T targeting CD7 (UCART7) would result in the efficient targeting and killing of malignant T cells without significant effector T cell fratricide or induction of GvHD. To generate the CD7 CAR, the anti-CD7 single chain variable fragment (scFv) was created using commercial gene synthesis and cloned into the backbone of a 3rd generation CAR with CD28 and 4-1BB internal signaling domains. The construct was modified to express CD34 via a P2A peptide to enable detection of CAR following viral transduction. Human primary T cells were activated using anti-CD3/CD28 beads for 48 hours prior to bead removal and electroporation with CD7 gRNA, TRAC gRNA, and Cas9 mRNA. On day three, T cells were transduced with lentivirus particles encoding either CD7 CAR or CAR CD19 control and allowed to expand for a further 6 days. Transduction efficiency and ablation of CD7 and TRAC were confirmed by flow cytometry. Multiplex CRISPR/Cas9 gene-editing resulted in the simultaneous bi-allelic deletion of both CD7 and TRAC in 72.8%±1.92 of cells, as determined by both non-homologous end joining (NHEJ) and FACS analyses. To prevent alloreactivity, CD3+ CAR-T were removed from the product by magnetic depletion. Of particular importance is that by using two distinct methods for assessing "off-target" nuclease activity across the entire human T cell genome (Guide-seq and probe capture), we could only detect one gene, an intronic modification of RMB33, that was inappropriately targeted using this approach. No obvious genomic rearrangements were detected by these analyses. UCART7 effectively expanded and killed T-ALL cell lines (CCRF-CEM, MOLT3, and HSB2) and human primary T-ALL blasts in vitro. Next, we tested the capacity of UCART7 to kill primary T-ALL in vivo without xenogeneic GvHD. Considerable expansion of alloreactive T cells, severe GvHD (mean clinical GvHD score = 5.66), and a robust graft vs. leukemia effect were observed in recipients of WT T cells. In contrast, GvHD was completely absent, T cells were undetectable, and considerable tumor burden was observed in mice receiving TRACΔ T cells. Mice receiving UCART7, however, had no GvHD and, unlike UCART19 controls, effectively cleared primary human T-ALL in NSG mice. Fratricide-resistant and allo-tolerant 'off-the-shelf' UCART7 signifies a novel strategy for treatment of relapsed and refractory T-ALL and non-Hodgkin's T cell lymphomas without a requirement for autologous T cells and represents the first clinically feasible adoptive T cell therapy for T cell malignancies. Disclosures No relevant conflicts of interest to declare.

scholarly journals A Phase I Study Evaluating the Safety and Persistence of Allorestricted WT1-TCR Gene Modified Autologous T Cells in Patients with High-Risk Myeloid Malignancies Unsuitable for Allogeneic Stem Cell Transplantation

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1367-1367
Author(s):  
Emma C Morris ◽  
Rita Tendeiro-Rego ◽  
Rachel Richardson ◽  
Thomas A Fox ◽  
Francesca Sillito ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
High Risk ◽  
Phase I ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Post Infusion ◽  
Equity Ownership ◽  
Acute Myeloid

Background:Patients with acute myeloid leukemia (AML), myelodysplasia (MDS) or tyrosine kinase inhibitor resistant chronic myeloid leukemia (CML) who are unsuitable for consolidative allogeneic stem cell transplantation (alloSCT) have high relapse rates following chemotherapy. Wilms' tumor 1 (WT1) is highly expressed in the majority of acute myeloid leukemias (AML) and in many subtypes of myelodysplasia (MDS) as well as other hematological and solid tumors. WT1 is an intracellular antigen, which makes it difficult to target using current Chimeric Antigen Receptor (CAR)-T cell technologies. The use of genetically modified T cells expressing WT1-specific α/β T cell receptors can re-direct T cell specificity via the recognition of intracellular peptides presented by MHC molecules on the malignant cell surface. Phase I clinical trials of WT1-TCR gene-modified T cells have been conducted in the settings of relapsed disease and post-alloSCT and preliminary data suggests this treatment approach is safe and potentially clinically effective in these cohorts (Tawara et al. Blood. 2017;130(18):1985-94; Chapuis et al, Nat Med. 2019;25(7):1064-72). Methods:We report a phase I/II safety and dose escalation study evaluating WT1-TCR gene-modified autologous T cells in HLA-A*0201 positive patients with AML, MDS and CML, unsuitable for alloSCT (NCT02550535) (Fig 1A). Patient T cells were harvested by leucapheresis and transduced with a retroviral vector construct encoding the codon optimised variable and constant a and bchains of the human pWT126-specific TCR separated by a self-cleaving 2A sequence (Fig 1B). Bulk transduced T cells were analysed by flow cytometry (CD3, CD8 and Vb2.1) prior to infusion and at regular intervals post-infusion. A quantitative PCR assay was developed to identify WT1-TCR expressing T cells in the peripheral blood post infusion. Patients received minimal conditioning with fludarabine and methylprednisolone prior to transfer of transduced T cells. All subjects were followed for a minimum of 12 months or until death. Results:A total of 10 patients (6 AML, 3 MDS and 1 TKI- resistant CML) were recruited. The mean age was 71.3 years (range 64-75) and all had high risk disease (by cytogenetic or clinical criteria). All AML patients were in complete morphological remission at the time of trial entry, whilst MDS patients had ≤ 15% blasts on bone marrow examination. All 10 patients received the gene-modified T cells in dose escalation cohorts (seven patients received £2x107/kg and three patients received £1x108/kg bulk WT1 TCR transduced cells). No adverse events directly attributable to the investigational product were recorded apart from one possible cytokine release syndrome, which was managed without tociluzimab. Transferred T cells demonstrated in vivoproliferation commensurate with maintenance of functional capacity despite ex vivo manipulation (Fig 1C and 1D). The TCR-transduced T cells were detectable in all patients at 28 days and in 7 patients persisted throughout the study period (Fig 1E). All 6 AML patients were alive at last follow up (median 12 months; range 7-12.8 months). The 3 patients with MDS had a median survival of 3 months (range 2.1-3.96 months) post T cell infusion. 2 died from progressive disease and one from other causes. 2 patients discontinued the study early due to disease progression. Conclusions: This is the second reported phase I/II clinical trial of autologous WT1-TCR gene-modified T cells for treatment of AML and MDS in a high-risk cohort of patients not suitable for alloSCT. We have shown that the WT1-TCR T cells demonstrated a strong safety profile without detectable on-target, off-tumour toxicity and no severe adverse events in the ten patients treated. An important cause of treatment failure for adoptive cellular therapies is the lack of persistence of transferred T cells leading to loss of disease specific effects. We demonstrated that autologous WT1-TCR T cells proliferated in vivoand persisted for many months. Recent work within our group (in press) has shown that TCRs modified to include key framework residues, show increased TCR expression and functional improvement. These modifications could be incorporated into future studies to improve efficacy. This data supports the rationale for a larger, phase II trial of WT1-TCR T cells in myeloid malignancies in patients for whom alloSCT is not appropriate, in order to assess clinical efficacy. Figure 1 Disclosures Morris: Quell Therapeutics: Consultancy, Other: Scientific Founder,stock; Orchard Therapeutics: Consultancy. Qasim:CellMedica: Research Funding; Bellicum: Research Funding; UCLB: Other: revenue share eligibility; Autolus: Equity Ownership; Orchard Therapeutics: Equity Ownership; Servier: Research Funding. Mount:Gamma Delta Therapeutics: Employment. Inman:Cellmedica: Employment. Gunter:Cellmedica: Employment. Stauss:Cell Medica: Other: I have stock; Quell Therapeutics: Consultancy, Other: I have stock.

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