scholarly journals Development of CAR-T Cell Constructs with Broad Anti-Tumor Tropism

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 24-24
Author(s):  
Ameet K. Mishra ◽  
Iris Kemler ◽  
David Dingli

Chimeric antigen receptor T (CAR-T) cell therapy is a transformative approach to cancer eradication. CAR-T is expensive in part due to the restricted use of each CAR construct for a specific set of tumors such as B cell lymphoma targeted with CD19 and multiple myeloma targeted with BCMA. A CAR construct with broad anti-tumor activity can be advantageous due to wide applicability and scalability of production. We show that CD126, the IL-6 receptor alpha, is an antigen that is expressed by many hematologic and solid malignancies including multiple myeloma, non-Hodgkin lymphoma, acute myeloid leukemia, pancreatic and prostate adenocarcinoma, non-small cell lung cancer and malignant melanoma amongst others. High CD126 expression is a negative prognostic marker in many malignancies. The two CD126 targeting CAR-T cell constructs contain the CD28 anchoring domain followed by 4-1BB and CD3 zeta signaling domain. Lentiviral vectors were generated with triple plasmid (CAR, psPAX2 and pMD2.G) transfection of 293T cells and the vector concentrated by ultracentrifugation and used to transduce human T cells. T cells were isolated from leuko-reduction cones using negative selection with magnetic beads. The transduction efficiency was around 60%. The T cells were activated with anti-CD3/CD28 beads and expanded for two weeks before using for downstream experiments. CD126 CAR-T cells are able to kill many tumor cells in an antigen specific manner and with an efficiency that is directly proportional to the cell surface expression of CD126 expression (rho = 0.6, p = 0.0019). The presence of soluble CD126 in the culture media did not interfere with CAR-T cell killing. The CAR-T constructs bind murine CD126. However, injection of CD126 targeting CAR-T cells in NSG mice did not lead to any evidence of hepatotoxicity and weight loss despite possible expression of this antigen on hepatocytes. In vivo studies in NSG mice with multiple myeloma (RPMI-8226) and prostate adenocarcinoma (DU-145) xenograft models (n=10 tumors per group) showed that the intravenously injected CD126 targeted CAR-T cells (107) infiltrated the tumors, expanded, produced human interferon gamma and killed the tumor cells (p<0.001). Bioluminescence imaging showed control of tumor growth in the actively treated tumors compared to the controls (p<0.05). At post mortem, mice injected with CD126 targeted CAR-T cells had smaller residual tumors compared to controls injected with non-engineered human T cells from the same donor. Binding of sIL-6R by CAR-T cells could mitigate cytokine release syndrome. In support of this, murine SAA-3 levels (the equivalent of human CRP) were lower in mice injected with CD126 CAR-T compared to controls (p<0.05), suggesting that binding of sIL-6R by CAR-T cells could mitigate cytokine release syndrome. CD126 provides a novel therapeutic for CAR-T cells in a broad variety of tumors with low risk of toxicity. Disclosures Dingli: Apellis: Consultancy; Millenium: Consultancy; Janssen: Consultancy; Bristol Myers Squibb: Research Funding; Sanofi-Genzyme: Consultancy; Alexion: Consultancy; Rigel: Consultancy; Karyopharm Therapeutics: Research Funding.

Author(s):  
Bill X. Wu ◽  
No-Joon Song ◽  
Brian P. Riesenberg ◽  
Zihai Li

Abstract The use of chimeric antigen receptor (CAR) T cell technology as a therapeutic strategy for the treatment blood-born human cancers has delivered outstanding clinical efficacy. However, this treatment modality can also be associated with serious adverse events in the form of cytokine release syndrome. While several avenues are being pursued to limit the off-target effects, it is critically important that any intervention strategy has minimal consequences on long term efficacy. A recent study published in Science Translational Medicine by Dr. Hudecek’s group proved that dasatinib, a tyrosine kinase inhibitor, can serve as an on/off switch for CD19-CAR-T cells in preclinical models by limiting toxicities while maintaining therapeutic efficacy. In this editorial, we discuss the recent strategies for generating safer CAR-T cells, and also important questions surrounding the use of dasatinib for emergency intervention of CAR-T cell mediated cytokine release syndrome.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 862-862 ◽  
Author(s):  
Partow Kebriaei ◽  
Stefan O. Ciurea ◽  
Mary Helen Huls ◽  
Harjeet Singh ◽  
Simon Olivares ◽  
...  

Background: Allogeneic hematopoietic cell transplantation (HCT) can be curative in a subset of patients with advanced lymphoid malignancies but relapse remains a major reason for treatment failure. Donor-derived, non-specific lymphocyte infusions (DLI) can confer an immune anti-malignancy effect but can be complicated by graft-versus-host-disease (GVHD). Chimeric antigen receptor (CAR)-modified T cells directed toward CD19 have demonstrated dramatic efficacy in patients with refractory ALL and NHL. However, responses are often associated with life-threatening cytokine release syndrome. Aim: We hypothesized that infusing CAR-modified, CD19-specific T-cells after HCT as a directed DLI would be associated with a low rate of GVHD, better disease control, and a less severe cytokine release syndrome since administered in a minimal disease state. Methods: We employed a non-viral gene transfer using the Sleeping Beauty (SB) transposon/transposase system to stably express a CD19-specific CAR (designated CD19RCD28 that activates via CD3z & CD28) in donor-derived T cells for patients with advanced CD19+ lymphoid malignancies. T-cells were electroporated using a Nucleofector device to synchronously introduce two DNA plasmids coding for SB transposon (CD19RCD28) and hyperactive SB transposase (SB11). T-cells stably expressing the CAR were retrieved over 28 days of co-culture by recursive additions of g-irradiated activating and propagating cells (AaPC) in presence of soluble recombinant interleukin (IL)-2 and IL-21. The AaPC were derived from K562 cells and genetically modified to co-express CD19 as well as the co-stimulatory molecules CD86, CD137L, and a membrane-bound version of IL-15. Results: To date, we have successfully treated 21 patients with median age 36 years (range 21-62) with advanced CD19+ ALL (n=18) or NHL (n=3); 10 patients had active disease at time of HCT. Donor-derived CAR+ T cells (HLA-matched sibling n=10; 1 Ag mismatched sibling n=1; haplo family n=8; cord blood n=2) were infused at a median 64 days (range 42-91 days) following HCT to prevent disease progression. Transplant preparative regimens were myeloablative, busulfan-based (n=10) or reduced intensity, fludarabine-based (n=11). All patients were maintained on GVHD prophylaxis at time of CAR T-cell infusion with tacrolimus, plus mycophenolate mofeteil for cord, plus post-HCT cyclophosphamide for haplo donors. The starting CAR+ T-cell dose was 106 (n=7), escalated to 107 (n=6), 5x107 (n=5), and currently at 108 (n=3) modified T cells/m2 (based on recipient body surface area). Patients have not demonstrated any acute or late toxicity to CAR+ T cell infusions. Three patients developed acute grades 2-4 GVHD (liver n=1, upper GI n=1, skin=1) which was within the expected range after allogeneic HCT alone. Of note, the rate of CMV reactivation after CAR T cell infusion was 24% vs. 41 % previously reported for our patients without CAR T cell infusion (Wilhelm et al. J Oncol Parm Practice, 2014, 20:257). Nineteen patients have had at least 30 days follow-up post CAR T-cell infusion and are evaluable for disease progression. Forty-eight percent of patients (n=10) remain alive and in complete remission (CR) at median 5.2 months (range 0-21.3 months) following CAR T cell infusion. Importantly, among 8 patients who received haplo-HCT and CAR, 7 remain in remission at median 4.2 months. Conclusion: We demonstrate that infusing donor-derived CD19-specific CAR+ T cells, using the SB and AaPC platform, in the adjuvant HCT setting as pre-emptive DLI may provide an effective and safe approach for maintaining remission in patients at high risk for relapse. Graft-vs-host disease did not appear increased by administration of the donor derived CAR-T cells. Furthermore, the add-back of allogeneic T cells appears to have contributed to immune reconstitution and control of opportunistic viral infection. Disclosures Huls: Intrexon and Ziopharm: Employment, Equity Ownership. Singh:Intrexon and Ziopharm: Equity Ownership, Patents & Royalties. Olivares:Intrexon and Ziopharm: Equity Ownership, Patents & Royalties. Su:Ziopharm and Intrexon: Employment. Figliola:Intrexon and Ziopharm: Equity Ownership, Patents & Royalties. Kumar:Ziopharm and Intrexon: Equity Ownership. Jena:Ziopharm Oncology: Equity Ownership, Patents & Royalties: Potential roylaties (Patent submitted); Intrexon: Equity Ownership, Patents & Royalties: Potential royalties (Patent submitted). Ang:Intrexon and Ziopharm: Equity Ownership. Lee:Intrexon: Equity Ownership; Cyto-Sen: Equity Ownership; Ziopharm: Equity Ownership.


Author(s):  
Jeremy S. Abramson ◽  
Matthew Lunning ◽  
M. Lia Palomba

Aggressive B-cell lymphomas that are primary refractory to, or relapse after, frontline chemoimmunotherapy have a low cure rate with conventional therapies. Although high-dose chemotherapy remains the standard of care at first relapse for sufficiently young and fit patients, fewer than one-quarter of patients with relapsed/refractory disease are cured with this approach. Anti-CD19 chimeric antigen receptor (CAR) T cells have emerged as an effective therapy in patients with multiple relapsed/refractory disease, capable of inducing durable remissions in patients with chemotherapy-refractory disease. Three anti-CD19 CAR T cells for aggressive B-cell lymphoma (axicabtagene ciloleucel, tisagenlecleucel, and lisocabtagene ciloleucel) are either U.S. Food and Drug Administration approved or in late-stage development. All three CAR T cells produce durable remissions in 33%–40% of treated patients. Differences among these products include the specific CAR constructs, costimulatory domains, manufacturing process, dose, and eligibility criteria for their pivotal trials. Notable toxicities include cytokine release syndrome and neurologic toxicities, which are usually treatable and reversible, as well as cytopenias and hypogammaglobulinemia. Incidences of cytokine release syndrome and neurotoxicity differ across CAR T-cell products, related in part to the type of costimulatory domain. Potential mechanisms of resistance include CAR T-cell exhaustion and immune evasion, CD19 antigen loss, and a lack of persistence. Rational combination strategies with CAR T cells are under evaluation, including immune checkpoint inhibitors, immunomodulators, and tyrosine kinase inhibitors. Novel cell products are also being developed and include CAR T cells that target multiple tumor antigens, cytokine-secreting CAR T cells, and gene-edited CAR T cells, among others.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2203-2203 ◽  
Author(s):  
Sowndharya Rajavel ◽  
Cade E. Ito ◽  
Keith Abe ◽  
Valerie Guerrero ◽  
Gene I. Uenishi ◽  
...  

Abstract Auto-reactive antibody production by plasma cells is the direct cause of many auto-immune diseases. In such cases elimination of plasma cells would ameliorate the disease. Chimeric antigen receptor T (CAR-T) cells with cytotoxicity toward cells expressing B-cell maturation antigen (BCMA) have shown remarkable promise for the treatment of multiple myeloma, a plasma cell neoplasm. Elimination of non-malignant plasma cells is a side-effect of anti-BCMA CAR-T treatment of multiple myeloma, suggesting the use of these anti-BCMA CAR T cells for auto-immune indications. Unfortunately, CAR-T administration requires use of lymphodepletion to achieve efficient cell engraftment, and is often accompanied by cytokine release syndrome (CRS), a potentially life-threatening side-effect. As lymphodepletion and CRS pose morbidity/mortality risks that are unacceptable for therapy of many auto-immune diseases, we have utilized CRISPR-Cas9 gene editing to develop a controllable CAR-T cell platform that provides for (1) engraftment with non-cytotoxic transient immunosuppression; and (2) small-molecule dependent CAR T-cell expansion. We have implemented this platform using a unique dual targeting approach in which a BCMA CAR transgene is integrated into the TRAC locus, and additional payloads are integrated into a second locus, thus also enabling an allogeneic manufacturing process. Transgene integration occurred in >50% of cells individually with several percent of cells targeted at two loci. TRAC-targeted, anti-BCMA CAR T cells demonstrated CAR-dependent, target-cell-BCMA-dependent cytotoxicity towards both high-BCMA- and low-BCMA-expressing cell lines and in multiple myeloma cells xenografted into NSG mice. Drug-regulation properties and immunosuppression resistance are the subject of ongoing experiments. Anti-BCMA CAR T cells that are chemically controlled, incapable of graft-versus-host disease, and insensitive to immunosuppression may be an attractive treatment option a variety of antibody-mediated auto-immune conditions. Disclosures Rajavel: Casebia Therapeutics: Employment. Ito:Casebia Therapeutics: Employment. Abe:Casebia Therapeutics: Employment. Guerrero:Casebia Therapeutics: Employment. Uenishi:Casebia Therapeutics: Employment. Scharenberg:Casebia Therapeutics: Employment; Generation Bio: Equity Ownership; Alpine Immune Sciences: Equity Ownership. Cost:Casebia Therapeutics: Employment.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 929-929 ◽  
Author(s):  
Chunrui Li ◽  
Jue Wang ◽  
Di Wang ◽  
Guang Hu ◽  
Yongkun Yang ◽  
...  

Background: Previous studies indicate that patients with relapsed/refractory multiple myeloma (RRMM) who receive BCMA-targeting CAR-T cells may achieve better remission but have a higher relapse rate. Persistence of CAR T cells post-infusion may be one determinant of the duration of response. Moreover, once the disease progresses again, the re-infusion of CAR-T cells is not effective. To solve this dilemma, we have developed a novel BCMA-targeting CAR-T (CT103A) with a lentiviral vector containing a CAR structure with a fully human scFv, CD8a hinger, and transmembrane, 4-1BB co-stimulatory and CD3z activation domains. Methods: ChiCTR1800018137 is a single-center and single-arm trial of CT103A in patients with RRMM (≥ 3 prior lines, including a proteasome inhibitor and an IMiD, or double refractory). The primary objectives are the incidence of adverse events (AEs), including dose-limiting toxicities (DLTs). The secondary objectives are the duration of clinical response, evaluation of minimal residual disease (MRD), progression-free and overall survival, and CAR-T cell persistence in blood. Between September 21, 2018, and August 1st, 2019, sixteen patients (including 4 patients having relapsed after being given a murine BCMA CAR-T and 5 patients having extramedullary disease and/or plasma cell leukemia) received CT103A in 3+3 dose-escalation trial (four doses at 1, 3, 6, 8 ×106/kg) after a conditioning chemotherapy regimen of cyclophosphamide and fludarabine. Median follow-up after CT103A infusion was 195 days (23 to 314 days) and all 16 patients were evaluable for initial (14 days) clinical response. Results: As of August 1st, 2019, the objective response rate was 100%, 6/16 patients achieved CR/sCR within two weeks post-infusion and all 8 patients surpassing 6 months achieved VGPR/CR/sCR. CR/sCR was 75%, and VGPR was 25% for these 8 patients, according to the IMWG Uniform Response Criteria for MM. In 4 patients who have participated in a prior CAR-T trial, three have achieved sCR, and 1 achieved VGPR. All 15 patients who could be evaluated for minimal residual disease (MRD) had MRD-negative status (≤10-4 nucleated cells by flow). The circulating CT103A cells were detected in the blood by flow and digital polymerase chain reaction, peaking at 14 days (ranging from 9 to 25), and remaining detectable in 12/16 patients, at the time of their last evaluation. Patient #1 (the first patient treated) has now exceeded 314 days of CART persistence, post-infusion. All sixteen patients developed cytokine release syndrome (according to ASBMT Consensus Grading for Cytokine Release Syndrome and Neurological Toxicity Associated with Immune Effector Cells: 10 Grade 1-2, 5 Grade 3,1 Grade 4). A grade 4 CRS appeared at the 6×106 /kg dose level and was considered as a dose-limiting toxicity DLT. No neurotoxicity was observed in all dose groups. One patient died of a lung infection 19 days post-infusion. Conclusions: Data from this early-stage clinical study showed the unparalleled safety and efficacy of CT103A in heavily pretreated R/R multiple myeloma patients. Highly active (ORR 100%) and rapid response within two weeks, suggests CT103A could be developed as a competitive therapy to treat patients with RRMM. Disclosures Hu: Nanjing Iaso Biotherapeutics Co. Ltd..: Employment. Yang:Nanjing Iaso Biotherapeutics Co.: Employment. Zhou:Nanjing Iaso Biotherapeutics Co. Ltd.: Other: Chairman of Advisory Committee of Science and Medicine .


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 30-31 ◽  
Author(s):  
Paolo F Caimi ◽  
Ashish Sharma ◽  
Patricio Rojas ◽  
Seema Patel ◽  
Jane Reese ◽  
...  

INTRODUCTION: Anti-CD19 chimeric antigen receptor T (CAR-T) cells have demonstrated activity against relapsed/refractory lymphomas. Cytokine release syndrome (CRS) and CAR-T related encephalopathy syndrome (CRES/ICANS) are well-known complications of CAR-T cell therapy. Tocilizumab, a humanized monoclonal antibody targeting the interleukin 6 (IL-6) receptor, is approved for treatment of CRS. Our institutional standard was modified to administer prophylactic tocilizumab before infusion CAR-T cell products. We present the outcomes of subjects treated with locally manufactured antiCD19 CAR-T cells (TNFRSF19 transmembrane domain, CD3Zeta/4-1BB costimulatory signaling) with and without prophylactic tocilizumab. METHODS: Relapsed / refractory (r/r) lymphoma patients (pts) treated with anti-CD19 CAR-T cells at our institution were included. Baseline demographic and clinical characteristics, as well as laboratory results were obtained from our Hematologic Malignancies and Stem Cell Therapy Database. Prior to institution of prophylactic tocilizumab, pts received this agent only if they presented evidence of CRS grade 2 or higher. In May 2019, our institutional practice changed to provide tocilizumab 8mg/kg, 1 hour prior to infusion of CAR-T cell product. CRS was measured according to the ASTCT Consensus Grading, whereas CRES was measured using the CARTOX-10 criteria. Comparisons between groups were done with the Mann-Whitney U test for continuous variables and Fisher's exact test for categorical variables. RESULTS: Twenty-three relapsed / refractory lymphoma pts were treated with antiCD19 CAR-T cells; 15 pts received prophylactic tocilizumab. Median follow up was 312 days (range 64 - 679) days. Baseline characteristics are listed in table 1. Both groups were similar: There were no statistically differences in the rate of bulky, refractory disease, prior ASCT or number or prior lines of therapy. Baseline lymphocyte counts, C - reactive protein (CRP) and were also comparable between groups (Table 2). We did not observe immune adverse reactions to tocilizumab infusion. There were no differences in the incidence of cytopenias or infectious complications between groups. CRS of any grade was observed in 6/8 (75%) of pts without prophylactic tocilizumab vs. 6/15 (40%) in pts treated with prophylactic tocilizumab (p = 0.23), whereas CRS grade >1 was observed in 5 pts (62.5%) without prophylactic tocilizumab and in 3 pts (20%) treated with prophylactic tocilizumab (p = 0.02). There was no significant difference in the incidence of all grade CRES (no prophylaxis, 3/8 [38%] pts; prophylaxis 5/15 [30%] pts, p = 0.2969). There was a statistically significant difference in the peak CRP and peak ferritin without difference in the peak lymphocyte count after CAR-T infusion (Table 2, Figure 1). Patients given prophylactic tocilizumab had higher IL-6 plasma concentrations on day 2 after infusion (Figure 2). Complete response was observed in 4/8 (50%) pts without prophylactic tocilizumab vs. 12/15 (80%) pts with prophylactic tocilizumab (p = 0.18). All pts had detectable Anti-CD19 CAR-T cells on day 30, both groups had peak CAR-T expansion on day 14, with no statistically significant differences in expansion rates between groups. All evaluable subjects have had CAR-T persistence on days 60, 90, 180, and 365. CONCLUSIONS: Use of prophylactic tocilizumab prior to infusion of antiCD19 CAR-T cells is associated with reduced incidence of severe CRS and decreased levels of clinical laboratory markers of inflammation, despite increases in plasma concentration of IL-6. This decreased rate of grade ≥2 CRS is not associated with impaired disease control and did not result in increased rates of neurologic toxicity. Prophylactic tocilizumab does not appear to affect CAR-T cell expansion or persistence. Figure 1 Disclosures Caimi: ADC therapeutics: Other: Advisory Board, Research Funding; Celgene: Speakers Bureau; Amgen: Other: Advisory Board; Bayer: Other: Advisory Board; Verastem: Other: Advisory Board; Kite pharmaceuticals: Other: Advisory Board. Worden:Lentigen, a Miltenyi biotec company: Current Employment. Kadan:Lentigen, a Miltenyi biotec company: Current Employment. Orentas:Lentigen Technology, a Miltenyi Biotec Company: Research Funding. Dropulic:Lentigen, a Miltenyi Biotec Company: Current Employment, Patents & Royalties: CAR-T immunotherapy. de Lima:Celgene: Research Funding; Pfizer: Other: Personal fees, advisory board, Research Funding; Kadmon: Other: Personal Fees, Advisory board; Incyte: Other: Personal Fees, advisory board; BMS: Other: Personal Fees, advisory board. OffLabel Disclosure: Use of tocilizumab as prophylaxis for CRS is not approved, whereas use for treatment is approved and on label.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ameet K. Mishra ◽  
Iris Kemler ◽  
David Dingli

AbstractChimeric antigen receptor T (CAR-T) cell therapy is a transformative approach to cancer eradication. CAR-T is expensive partly due to the restricted use of each CAR construct for specific tumors. Thus, a CAR construct with broad antitumor activity can be advantageous. We identified that CD126 is expressed by many hematologic and solid tumors, including multiple myeloma, lymphoma, acute myeloid leukemia, pancreatic and prostate adenocarcinoma, non-small cell lung cancer, and malignant melanoma among others. CAR-T cells targeting CD126 were generated and shown to kill many tumor cells in an antigen-specific manner and with efficiency directly proportional to CD126 expression. Soluble CD126 did not interfere with CAR-T cell killing. The CAR-T constructs bind murine CD126 but caused no weight loss or hepatotoxicity in mice. In multiple myeloma and prostate adenocarcinoma xenograft models, intravenously injected CD126 CAR-T cells infiltrated within, expanded, and killed tumor cells without toxicity. Binding of soluble interleukin-6 receptor (sIL-6R) by CAR-T cells could mitigate cytokine release syndrome. Murine SAA-3 levels were lower in mice injected with CD126 CAR-T compared to controls, suggesting that binding of sIL-6R by CAR-T cells could mitigate cytokine release syndrome. CD126 provides a novel therapeutic target for CAR-T cells for many tumors with a low risk of toxicity.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. LBA-1-LBA-1 ◽  
Author(s):  
Syed Abbas Ali ◽  
Victoria Shi ◽  
Michael Wang ◽  
David Stroncek ◽  
Irina Maric ◽  
...  

Abstract B-cell maturation antigen (BCMA) is a protein expressed by normal and malignant plasma cells. We are conducting a phase I clinical trial of an anti-BCMA chimeric antigen receptor (CAR-BCMA) that incorporates an anti-BCMA single-chain variable fragment, a CD28 domain, and a CD3-zeta T-cell activation domain (Carpenter et al. Clinical Cancer Research 2013). Autologous T cells are genetically modified to express the CAR with a gamma-retroviral vector. Patients receive a single infusion of CAR-BCMA T cells. Before the CAR T-cell infusions, patients receive a chemotherapy regimen of 300 mg/m2 of cyclophosphamide and 30 mg/m2 of fludarabine with each chemotherapy agent given daily for 3 days. The purpose of the chemotherapy is to enhance activity of the CAR T cells by depleting endogenous leukocytes. Twelve patients have been enrolled, and 11 patients have been treated on one of 4 dose levels, 0.3x106, 1x106, 3x106, and 9x106CAR+ T cells/kg of bodyweight. Patients had advanced multiple myeloma (MM) with a median of 7 prior lines of therapy. Of the 6 patients treated on the lowest 2 dose levels, one patient had a transient partial remission (PR) of 2 weeks duration; the other 5 patients had responses of stable disease (SD). On the 3rddose level, 2 patients obtained responses of stable disease, and one patient obtained a response of very good PR (VGPR) with complete elimination of MM bone disease on positron emission tomography (PET) scan, normalization of serum free light chains, and clearance of bone marrow plasma cells. Toxicity among patients on the first 3 dose levels was mild and included cytopenias attributable to chemotherapy, fever in 3 patients, and signs of cytokine release syndrome including tachycardia and hypotension in Patient 8 who had a VGPR. Two patients have been treated on the highest dose level of 9x106CAR+ T cells/kg. The first patient on this dose level, Patient 10, had MM making up 90% of total bone marrow cells before treatment. Starting 4 hours after infusion of CAR T cells, Patient 10 exhibited signs of cytokine release syndrome including fever, tachycardia, dyspnea, acute kidney injury, coagulopathy, hypotension requiring vasopressor support, and muscle damage manifesting as an elevated creatine kinase level and weakness. His neutrophil count was less than 500/µL before the CAR-BCMA T-cell infusion and remained below 500/µL for 40 days after the CAR T-cell infusion before recovering. He also experienced prolonged thrombocytopenia. Patient 10’s myeloma was rapidly eliminated after CAR-BCMA T-cell infusion. By immunohistochemistry staining for CD138, bone marrow plasma cells decreased from 90% before treatment to 0% one month after the CAR T-cell infusion. The serum M-protein decreased from 1.6 g/dL before treatment to undetectable 2 months after treatment. The serum and urine immunofixation electrophoresis tests were negative 2 months after the CAR T-cell infusion. Patient 10’s current myeloma response is stringent complete remission. The second patient treated on the 9x106CAR+ T cells/kg dose level, Patient 11, had IgG lambda MM with 80% bone marrow plasma cells before treatment. Patient 11 experienced signs of cytokine release syndrome with toxicities including fever, tachycardia, hypotension, delirium, hypoxia, and coagulopathy. Patient 11’s M-protein decreased from 3.6 g/dL before treatment to 0.8 g/dL 4 weeks after treatment. His serum lambda free light chain decreased from 95.9 mg/dL before treatment to 0.15 mg/dL 4 weeks after treatment. Four weeks after CAR T-cell infusion, bone marrow plasma cells were undetectable. T cells containing the CAR-BCMA gene were detected in the blood of all 10 patients evaluated with peak levels of 0.04 to 18.2% of blood mononuclear cells. Patient 10 had the highest peak absolute number of blood CAR T cells with 51 CAR+ T cells/µL. Blood levels of IL-6 and other inflammatory cytokines were highest in patients with clinical signs of cytokine release syndrome, and the 3 patients with the highest serum IL-6 levels also had the most impressive anti-myeloma responses. Before treatment, the mean serum BCMA level of treated patients was 243 ng/mL. In responding patients, serum BCMA levels decreased after treatment. Toxicities in patients receiving CAR-BCMA T cells were similar to toxicities in leukemia patients treated with anti-CD19 CAR T cells. Our findings demonstrate strong anti-myeloma activity in the first clinical trial of a CAR targeting BCMA. Disclosures: Wang: Celgene: Research Funding. Kochenderfer:bluebird bio Inc.: Research Funding. Off Label Use: Use of cyclophosphamide and fludarabine as a conditioning regimen for adoptively-transferred T cells will be part of the presentation.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 997-997
Author(s):  
Margherita Norelli ◽  
Monica Casucci ◽  
Barbara Camisa ◽  
Laura Falcone ◽  
Catia Traversari ◽  
...  

Abstract Background: Chimeric antigen-receptor (CAR)-engineered T cells promise to cure chronic and acute leukemias refractory to standard treatments. Before this promise is fulfilled, however, two crucial issues need to be solved: i) how to circumvent the emergence of secondary resistance (e.g. due totarget-antigen loss; leukemic lineage switch); ii) how to manage associated toxicities (e.g. the cytokine release syndrome, CRS; lineage aplasias). Unfortunately, all these issues cannot be addressed pre-clinically in currently available NSG mouse models, because they lack human hematopoiesis and, furthermore, ultimately develop xenograft-versus-host disease (X-GVHD), preventing the evaluation of long-term effects. Methods: We have developed an innovative xenotolerant model by transplanting human hematopoietic stem cells (HSCs) intraliver in newborn NSG mice triple transgenic for human SCF, GM-SCF and IL-3 (SGM3). Differently from "classical" NSG, SGM3 mice reconstituted high levels of human T cells (>1000 cells per microL at week 8), which, once transferred in secondary recipients, persisted up to 200d without causing X-GVHD, even after irradiation. Robust and specific xenotolerance was confirmed by in vitrohyporesponsiveness to NSG, bot not to C57/Bl6 antigens (irradiated splenocytes) or human HLAs (PBMCs). Secondary transfer experiments in leukemic and/or HSC-humanized SGM-3 mice have been then designed for studying the determinants of CAR-T cell efficacy and associated toxicities in the absence of confounding xenoreactivity. Results: SGM3-derived T cells were transduced ex vivo with either a CD19 or a CD44v6 CAR (both having a CD28 2G design) after activation with CD3/CD28-beads and IL-7/IL-15, resulting in a preferential and functional CD45RA+/CD62L+/CD95+ stem memory T cell (TSCM) phenotype. Once transferred in secondary recipients previously engrafted with a CD19+/CD44v6 leukemic cell line, CD19 or CD44v6 CAR-T cells equally mediated rapid tumor clearance both in low and high tumor-burden settings, in the absence of malaise or elevated human IL-6 levels in vivo. At later time points (after 100d), however, approximately 50% of responding mice relapsed despite significant CAR-T cell persistence in vivo (>50 cells per microL). A significant fraction of leukemia relapses were characterized by post-transcriptional down-regulation of CD44v6 expression or CD19 loss, respectively. Conversely, secondary transfer of SGM3-derived CAR-T cells in leukemic SGM3 mice that had been previously humanized with HSCs resulted in the development of a clinical syndrome similar to the CRS observed in clinical trials (high fevers, elevated IL-6, TNF-alpha and serum amyloid A levels - mouse analog of C-reactive protein in humans), resulting in 30% lethality. This CRS was anticipated and shortened for CD44v6 compared with CD19 CAR-T cells and worse in the case of 4-1BB compared with the original CD28 2G CAR designs. Strikingly, mice recovering from the CRS benefited from durable leukemic remissions, yet experienced long-lasting CD19+ B-cell or CD44v6+ monocyte aplasias. Deepness of remission was confirmed in "tertiary" recipients, which did not develop leukemia after the infusion of bone-marrow cells from mice in remission 150d since CAR-T cell infusion. Interestingly, in this model, tocilizumab administration at the time of either CD19 or CD44v6 CAR-T cell infusion efficiently prevented the CRS, but did not interfere with their comparable and long-term anti-leukemic effects. Conversely, depleting monocytes/macrophages before therapeutic CAR-T cell infusion by either lyposomal clodronate or by the prophylactic CD44v6 CAR-T cells inhibited CRS development, but also resulted in significantly worse leukemia-free survival (at 250d, 0% vs 80%, P<0.0001). Conclusions: A number of lessons can be learned from this innovative xenotolerant mouse model of CAR-T cell immunotherapy: monocytes are required for both i) optimal anti-leukemic efficacy, and ii) the occurrence of CRS; iii) tocilizumab prevents the CRS without interfering with efficacy; iv) monocyte aplasia induced by CD44v6 CAR-T cells does not impact on their efficacy, at least in the theraeputic setting, and may ameliorate CRS toxicity. As for CD44v6 CAR-T cells, this model could be used for effectively predicting the efficacy and associated toxicities of new CAR-T cell therapies, speeding up their clinical development. Disclosures Traversari: MolMed SpA: Employment. Bordignon:MolMed SpA: Employment. Ciceri:MolMed SpA: Consultancy. Bonini:TxCell: Membership on an entity's Board of Directors or advisory committees; Molmed SpA: Consultancy. Bondanza:Formula Pharmaceuticals: Honoraria; TxCell: Research Funding; MolMed SpA: Research Funding.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1921-1921 ◽  
Author(s):  
Henia Dar ◽  
Daniel Henderson ◽  
Zinkal Padalia ◽  
Ashley Porras ◽  
Dakai Mu ◽  
...  

Abstract Autologous CAR-T cells targeting BCMA have induced robust and durable responses in patients with relapsed/refractory multiple myeloma. However, autologous cell therapies face several challenges which will likely limit the number of patients that will have access to these therapies. These limitations include manufacturing failure rates, wait time and supply constraints in addition to other factors such as reimbursement. Allogeneic CAR-T cells can potentially overcome these access challenges, and may have several other advantages over autologous therapies. Allogeneic CAR-T cells are derived from robust healthy donor T cells through a batch manufacturing process, which may result in a highly consistent product with greater potency and enable better safety management. Here we show further development and preclinical data for CTX120, an allogeneic "off the shelf" CAR-T cell targeting BCMA. CTX120 is produced using the CRISPR/Cas9 system to eliminate TCR and MHC class I, coupled with specific insertion of the CAR at the TRAC locus. CTX120 shows consistent and high percent CAR expression from this controlled insertion and exhibits target-specific cytotoxicity and cytokine secretion in response to BCMA positive cell lines. CTX120 CAR-T cells retain their cytotoxic capacity over multiple in vitro re-challenges, demonstrating durable potency and lack of exhaustion. In mouse models of multiple myeloma, CTX120 showed typical CAR-T persistence and eliminated tumors completely, resulting in long-term survival as compared to untreated animals. These data support the ongoing development of CTX120 for treatment of patients with multiple myeloma and further demonstrate the potential for our CRISPR/Cas9 engineered allogeneic CAR-T platform to generate potent CAR-T cells targeting different tumor antigens. Disclosures Dar: CRISPR Therapeutics: Employment, Equity Ownership. Henderson:CRISPR Therapeutics: Employment, Equity Ownership. Padalia:CRISPR Therapeutics: Employment, Equity Ownership. Porras:CRISPR Therapeutics: Employment, Equity Ownership. Mu:CRISPR Therapeutics: Employment, Equity Ownership. Kyungah:CRISPR Therapeutics: Employment, Equity Ownership. Police:CRISPR Therapeutics: Employment, Equity Ownership. Kalaitzidis:CRISPR Therapeutics: Employment, Equity Ownership. Terrett:CRISPR Therapeutics: Employment, Equity Ownership. Sagert:CRISPR Therapeutics: Employment, Equity Ownership.


Sign in / Sign up

Export Citation Format

Share Document