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.

Targeting T-Cell Receptor β-Constant Domain for Immunotherapy of T-Cell Malignancies

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 811-811
Author(s):  
Paul Michael Maciocia ◽  
Patrycja Wawrzyniecka ◽  
Brian Philip ◽  
Ida Ricciardelli ◽  
Ayse U. Akarca ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cell Lines ◽  
Jurkat Cells ◽  
Car T Cells ◽  
T Cell Lymphomas ◽  
Car T ◽  
Equity Ownership ◽  
T Cell Malignancies

Abstract T-cell lymphomas and leukemias are aggressive, treatment-resistant cancers with poor prognosis. Immunotherapeutic approaches have been limited by a lack of target antigens discriminating malignant from healthy T-cells. While treatment of B-cell cancers has been enhanced by targeting pan B-cell antigens, an equivalent approach is not possible for T-cell malignancies since profound T-cell depletion, unlike B-cell depletion, would be prohibitively toxic. We propose an immunotherapeutic strategy for targeting a pan T-cell antigen without causing severe depletion of normal T-cells. The α/β T-cell receptor (TCR) is a pan T-cell antigen, expressed on >90% of T-cell lymphomas and all normal T-cells. An overlooked feature of the TCR is that the β-constant region comprises 2 functionally identical genes: TRBC1 and TRBC2. Each T-cell expresses only one of these. Hence, normal T-cells will be a mixture of individual cells expressing either TRBC1 or 2, while a clonal T-cell cancer will express TRBC1 or 2 in its entirety. Despite almost identical amino acid sequences, we identified an antibody with unique TRBC1 specificity. Flow cytometry (FACS) of T-cells in normal donors (n = 27) and patients with T-cell cancers (n = 18) revealed all subjects had TRBC1 and 2 cells in both CD4 and CD8 compartments, with median TRBC1 expression of 35% (range 25-47%). In addition, we examined viral-specific T-cells in healthy volunteers, by generation of Epstein Barr virus-specific primary cytotoxic T-cell lines (3 donors) or by identification of cytomegalovirus-specific (3 donors) or adenovirus-specific (5 donors) T-cells by peptide stimulation. We demonstrated similar TRBC1: 2 ratios in viral-specific cells, suggesting that depletion of either subset would not remove viral immunity. Next, using FACS and immunohistochemistry, we showed that TCR+ cell lines (n = 8) and primary T-cell lymphomas and leukemias (n = 55) across a wide range of histological subtypes were entirely restricted to one compartment (34% TRBC1). As proof of concept for TRBC-selective therapy, we developed anti-TRBC1 chimeric antigen receptor (CAR) T-cells. After retroviral transduction of healthy donor T-cells, comprising mixed TRBC1/2 populations, 90% of T-cells expressed CAR on the cell surface. No detectable TRBC1 T-cells remained in the culture, suggesting selective depletion of this population. Anti-TRBC1 CAR T-cells secreted interferon-γ in response to TRBC1-expressing target cell lines (p<0.001) or autologous normal TRBC1+ cells (p<0.001), and not TRBC2 cell lines or autologous normal TRBC2 cells. Anti-TRBC1 CAR killed multiple TRBC1 cell lines (p<0.001) and autologous normal TRBC1 cells (p<0.001), and not TRBC2 cell lines or autologous normal TRBC2 cells. These cell-line based findings were confirmed using primary cells from two patients with TRBC1+ adult T-cell leukaemia/lymphoma. We demonstrated specific tumour kill by allogeneic or autologous T-cells in vitro, despite partial downregulation of surface TCR by tumour cells. We developed a xenograft murine model of disseminated T-cell leukemia by engrafting engineered firefly luciferase+ TRBC1+ Jurkat cells in NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice. Bioluminescent imaging and FACS of marrow at 5 days following IV T-cell injection showed that while mice treated with untransduced T-cells progressed, mice receving anti-TRBC1 CAR T-cells had disease clearance (p<0.0001). In a further model, mice were engrafted with equal proportions of TRBC1-Jurkat and TRBC2-Jurkat cells. FACS analysis of bone marrow at 5 days following T-cell injection demonstrated specific eradication of TRBC1 and not TRBC2 tumour by anti-TRBC1 CAR (p<0.001). In summary, we have demonstrated a novel approach to investigation and targeting of T-cell malignancies by distinguishing between two possible TCR β-chain constant regions. Using CART-cells targeting TRBC1 we have demonstrated proof of concept for anti-TRBC immunotherapy. Unlike non-selective approaches targeting the entire T-cell population, TRBC targeting could eradicate a T-cell tumour while preserving sufficient normal T-cells to maintain cellular immunity. Disclosures Maciocia: Autolus: Equity Ownership, Patents & Royalties: TRBC1 and 2 Targeting for the Diagnosis and Treatment of T-cell Malignancies. Philip:Autolus: Equity Ownership. Onuoha:Autolus: Employment, Equity Ownership. Pule:Amgen: Honoraria; Roche: Honoraria; UCL Business: Patents & Royalties; Autolus Ltd: Employment, Equity Ownership, Research Funding.

scholarly journals Transcend NHL 001: Immunotherapy with the CD19-Directed CAR T-Cell Product JCAR017 Results in High Complete Response Rates in Relapsed or Refractory B-Cell Non-Hodgkin Lymphoma

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4192-4192 ◽  
Author(s):  
Jeremy S. Abramson ◽  
Lia Palomba ◽  
Leo I Gordon ◽  
Matthew Lunning ◽  
Jon Arnason ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Research Funding ◽  
Employment Equity ◽  
Car T Cells ◽  
Car T Cell ◽  
Non Hodgkin Lymphoma ◽  
Car T ◽  
Equity Ownership

Abstract Background: Based on promising results seen in patients treated with CD19-directed CAR-T cells in relapsed or refractory (R/R) pediatric B-cell acute lymphoblastic leukemia (Gardner, ASCO 2016) and adult B-cell non-Hodgkin lymphoma (Turtle, ASCO 2016), we are conducting a multicenter phase 1 trial of JCAR017 in R/R diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) (ClinicalTrials.gov Identifier: NCT02631044). JCAR017 is a second-generation, CD19-directed CAR-T cell product of defined cellular composition consisting of a 1:1 ratio of CD8+:CD4+ CAR+ T cells. Methods: Patients with R/R DLBCL (de novo or transformed from indolent lymphoma), follicular lymphoma grade 3B, or MCL and adequate organ function are eligible. There was no minimum absolute lymphocyte count (ALC) requirement for apheresis and no test expansion required. Treatment includes lymphodepletion (fludarabine 30 mg/m2 and cyclophosphamide 300 mg/m2 daily for 3 days) and JCAR017 given 2-7 days post-lymphodepletion at a starting dose of 5 x 107 CAR+ T cells (DL1). Single-dose and two-dose schedules are being evaluated. Primary objectives include safety and pharmacokinetics (PK) of JCAR017 measured by flow cytometry and quantitative PCR. Secondary objectives include complete and overall response (CR, OR) rates and duration of response (DOR). Response is assessed using the Lugano (2014) criteria. Results: As of August 1, 2016, 39 patients have been enrolled and 28 patients apheresed. Fourteen patients have been treated, all at DL1. Eight were male and 6 female. Thirteen patients had DLBCL and 1 had MCL. Median age was 61 years (range 37-79) and median number of prior therapies was 5 (range 2-9). Ten patients had undergone prior transplant (7 autologous; 3 allogeneic). Of the 14 patients, there were no cases of severe cytokine release syndrome (sCRS); 3 patients had low grade CRS (21%) (2 grade 1; 1 grade 2) and none required treatment with tocilizumab. Two of the 14 treated patients (14%) had neurotoxicity: 1 grade 4 encephalopathy and 1 grade 4 seizure. Both were in patients with DLBCL and were dose-limiting toxicities. Two deaths were seen in the DLBCL group and were due to disease progression. Twelve patients had at least 1 post-treatment response assessment; 11 patients with DLBCL and 1 with MCL. The patient with MCL had progressive disease at day 29 (D29). In the DLBCL group, response rates were: 82% (9/11) OR, 73% (8/11) CR, 9% (1/11) PR and 18% (2/11) PD at the time of post-treatment assessment on D29. All but one patient who achieved a CR were in remission at the time of this data cut. One DLBCL patient in CR had a parenchymal brain lesion in the right temporal lobe that also completely resolved. Of note, this patient had no CRS or neurotoxicity associated with JCAR017 treatment. The PK profile of JCAR017 in the peripheral blood and bone marrow show cellular expansion in all patients with persistence out to at least 3 months in patients with adequate follow up. Exploratory biomarker analyses will be presented at the meeting along with updated clinical data. Conclusions: Treatment with the defined cellular composition product JCAR017 following lymphodepletion with fludarabine and cyclophosphamide results in high CR rates in patients with heavily pretreated DLBCL, including the first report of a CR in a patient with secondary CNS lymphoma. Observed toxicities are manageable and compare favorably to other reported CAR T-cell products. Disclosures Abramson: Gilead: Consultancy; Kite Pharma: Consultancy; Abbvie: Consultancy; Seattle Genetics: Consultancy. Gordon:Northwestern University: Patents & Royalties: Patent for gold nanoparticles pending. Lunning:Celgene: Consultancy; Bristol-Myer-Squibb: Consultancy; Pharmacyclics: Consultancy; Genentech: Consultancy; Juno: Consultancy; AbbVie: Consultancy; Gilead: Consultancy; TG Therapeutics: Consultancy; Spectrum: Consultancy. Arnason:Gilead: Consultancy. Forero-Torres:Genentech/Roche: Research Funding; Seattle Genetics: Research Funding; Juno: Research Funding; Incyte: Research Funding; Abbvie: Research Funding; Novartis: Research Funding; Pfizer: Research Funding. Albertson:Juno Therapeutics: Employment, Equity Ownership. Sutherland:Juno therapeutics: Employment. Xie:Juno Therapeutics: Employment, Equity Ownership. Snodgrass:Juno therapeutics: Employment. Siddiqi:Pharmacyclics, LLC, an AbbVie Company: Speakers Bureau; Janssen: Speakers Bureau; Seattle Genetics: Speakers Bureau; Kite pharma: Other: Funded travel, 1 day registration, and 1 night hotel stay for EHA2016 so I could present trial data there.

scholarly journals Structure Guided Engineering of Highly Specific Chimeric Antigen Receptors for the Treatment of T Cell Lymphomas

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1661-1661 ◽  
Author(s):  
Shimobi Onuoha ◽  
Mathieu Ferrari ◽  
Anna Bulek ◽  
Reyisa Bughda ◽  
Somayya Manzoor ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
T Cells ◽  
T Cell ◽  
Cell Lines ◽  
Beta Chain ◽  
Employment Equity ◽  
Car T Cells ◽  
T Cell Lymphomas ◽  
Car T ◽  
Equity Ownership

Abstract Introduction Mature T cell lymphomas are aggressive, treatment resistant cancers that are associated with poor prognosis. Clinical application of immunotherapeutic approaches has been limited by a lack of target antigens that discriminate malignant from healthy T cells. Unlike B cell depletion, pan-T cell aplasia is prohibitively toxic. Previously we reported a targeting strategy based on the mutually exclusive expression of T cell receptor beta-chain constant domains 1 and 2 (TRBC1 and TRBC2). We identified an antibody with unique TRBC1 specificity and demonstrated that anti TRBC1 chimeric antigen receptor (CAR) T cells can ablate cells expressing TRBC1 TCRs while sparing those expressing TRBC2 TCRs. A phase I clinical study investigating the efficacy of our TRBC1 CAR is ongoing. T cell malignancies are clonal, and the ratio of TRBC2 to TRBC1 expressing lymphoma cases is predicted to be approximately 2:1. To treat all cases of T cell lymphoma, a CAR that targets TRBC2 is needed. TRBC1 and 2 are highly homologous. Structural studies suggest that amino acid inversions at positions 4 and 5 of the constant beta chain provide an accessible discriminating portion between the two proteins. Given the structural similarities between TRBC1 and TRBC2 and our characterized binder against TRBC1, we explored generating antibodies with specificity towards TRBC2 via a structure guided computational biology approach; engineering the previously identified TRBC1 antibody and reversing its specificity such that it recognised TRBC2. Results The crystal structure of the TRBC1 specific monoclonal antibody was solved in complex with a TRBC1-TCR to 2.4Å, Figure 1. Through computational biology and protein engineering we rationally designed a mutant version of TRBC1 binder that was specific for TRBC2 and had a 1000 fold decreased affinity towards TRBC1. Flow cytometry analysis of the TRBC2 specific antibody demonstrated the ability to bind to T-cells expressing TRBC2 TCRs. We further showed that the engineered antibody retained favourable biophysical characteristics with high stability (Fab Tm > 65oC) and low aggregation propensity (>99% monomer). We used the engineered monoclonal antibody to generate a 2nd generation anti-TRBC2 CAR. We demonstrated that our anti-TRBC2 CAR showed specificity, cytokine release and cytotoxicity in 72hr co-cultures against TRBC2+ cell lines but not TRBC1+ cell lines or cell lines that did not express TCR on the surface. Anti-TRBC2 CAR T-cells also demonstrated proliferative capacity in long-term co-culture assays. Conclusions We have utilised structural biology and rational protein design to generate CAR-T cells capable of specifically targeting TRBC2. The combination of TRBC1 and 2 targeting CAR-T cell products with a patient stratification companion diagnostic assay offers a therapeutic strategy for the treatment of a wide range of, otherwise untreatable, T-cell lymphomas. Figure 1. A. Structural interface between TCR Beta and Fab fragment of TRBC1 specific antibody. B and C. CDR fold of TRBC1 binder and 90o rotation. Disclosures Onuoha: Autolus Ltd: Employment, Equity Ownership, Patents & Royalties. Ferrari:Autolus Ltd: Employment, Equity Ownership. Bulek:Autolus Ltd: Employment, Equity Ownership, Patents & Royalties. Bughda:Autolus Ltd: Employment, Equity Ownership, Patents & Royalties. Manzoor:Autolus Ltd: Employment, Equity Ownership, Patents & Royalties. Srivastava:Autolus Ltd: Employment, Equity Ownership. Ma:Autolus Ltd: Employment. Karattil:Autolus Ltd: Employment, Equity Ownership, Patents & Royalties. Kinna:Autolus Ltd: Employment, Equity Ownership. Thomas:Autolus Ltd: Employment, Equity Ownership, Patents & Royalties. Cordoba:Autolus Ltd: Employment; Autolus Ltd: Patents & Royalties; Autolus Ltd: Equity Ownership. Maciocia:Autolus: Equity Ownership, Patents & Royalties: UCLB. Pule:Autolus Ltd: Employment, Equity Ownership, Other: Salary contribution paid for by Autolus, Research Funding; University College London: Patents & Royalties: Patent with rights to Royalty share through UCL.

scholarly journals Pharmacodynamic Profile and Clinical Response in Patients with B-Cell Malignancies of Anti-CD19 CAR T-Cell Therapy

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2042-2042 ◽  
Author(s):  
Arianne Perez ◽  
Lynn Navale ◽  
John M. Rossi ◽  
Yueh-wei Shen ◽  
Yizhou Jiang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
B Cell Malignancies ◽  
Employment Equity ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Clinical Responses ◽  
Equity Ownership

Abstract This study is supported in part by funding from the CooperativeResearch and Development Agreement (CRADA) between the National Cancer Institute and Kite Pharma Introduction: Chimeric antigen receptor (CAR) engineered autologous T-cell therapy has shown promising efficacy in B-cell malignancies in an ongoing phase 1 study (Kochenderfer et al. J Clin Oncol 2014). Anti-CD19 CAR T-cell product characteristics and potential pharmacodynamic markers from patients in this study were evaluated together with updated clinical responses. Methods: In this National Cancer Institute (NCI) clinical trial (NCT00924326), patients with relapsed/refractory B-cell malignancies received conditioning with cyclophosphamide and fludarabine daily for 3 days starting on day -5; followed by 1-2 x 106/kg anti-CD19 CAR T cells engineered with a CAR expressing CD28 and CD3-zeta signaling domains. Forty one cytokines, chemokines and immune response related markers were measured in the serum of patients prior to conditioning and CAR T-cell infusion, and during an interval of 4 weeks post-CAR T-cell infusion. EMD Millipore Luminex® xMAP® multiplex assays were used to measure all analytes. A Luminex 200™ instrument and xPONENT® 3.1 software were used for data acquisition and analysis. Major T-cell phenotypic markers including CD4, CD8, CD45RA and CCR7 were evaluated by multicolor flow cytometry on CAR-expressing T cells prior to and post-infusion, using a BD FACSCanto II. FlowJo software was used for data analysis. T-cell marker expression, as well as cytokine and chemokine levels were analyzed together with the clinical response to anti-CD19 CAR T cells. Maximum fold increase (MFI) was defined as the maximum fold change of measured analytes above baseline (pre-conditioning, day -5) across sampling timepoints. Results: Anti-CD19 CAR T-cell products, PBMCs from 12 patients, and serum samples from 15 patients have been evaluated. In 12 patient lots evaluated to date, the median CD4+/CD8+ CAR T-cell ratio was 0.48 (range 0.02-6.12). In addition, the median ratio between naïve (TN) plus central memory T cells (TCM), and more differentiated effector memory (TEM) plus effector cells (TE), was 0.48 (range 0.1-16.8). Post-hoc analyses adjusted for multiple comparisons showed that the frequency of CD4+ TN and TCM cells in the 6-8 day T-cell lots was significantly greater than that of CD4+ TN and TCM cells in the 10 day T-cell lots. The corresponding frequencies of CD8+ TN and TCM cells in the 6-8 day T-cell lots compared to 10 day T-cell lots approached significance, but did not meet the threshold after multiplicity adjustment. Clinical responses were seen across broad ranges of CD4+/CD8+ and (TN+TCM)/(TEM+TE) ratios in the CAR T-cell product. CAR T cells upregulated T-cell activation and immune modulating markers, as well as released measurable levels of cytokines and chemokines in response to CAR engagement of CD19 in vitro, or post-infusion. Cytokine and chemokine levels achieved their peak 3-10 days post T-cell infusion and returned to baseline generally within 3 weeks. Key pro-inflammatory cytokines and markers were upregulated: IL-6 median fold increase (MFI) at peak of 66 (interquartile range 5-152), IFN-g MFI 57 (13-126), C-reactive protein MFI 6 (4-42); immune homeostatic cytokines IL-15 MFI 19 (7-54), IL-2 MFI 20 (4-22), IL-10 MFI 10 (4-15); chemokines monocyte chemotactic protein (MCP)-1 MFI 7 (5-9), MCP-4 MFI 4 (2-5); and the immune effector molecules granzyme A MFI 7 (6-17) and granzyme B MFI 5 (3-9). Further analyses are ongoing. Conclusion: Clinical responses were observed irrespective of the CD4+/CD8+ ratio in the CAR T cell product. Cytokines and immune effector mediators peaked and cleared within 3 weeks. This pharmacodynamic profile reveals a rapid and coordinated sequence of T cell activation underlying durable responses in patients with B-cell malignancies. Disclosures Perez: Kite Pharma: Employment, Equity Ownership. Navale:Kite Pharma: Employment, Equity Ownership; Amgen: Equity Ownership. Rossi:Kite Pharma: Employment, Equity Ownership; Amgen: Equity Ownership. Shen:Kite Pharma: Employment, Equity Ownership. Jiang:Kite Pharma: Employment, Equity Ownership. Sherman:Amgen: Equity Ownership; Kite Pharma: Employment, Equity Ownership. Mardiros:Kite Pharma: Employment, Equity Ownership. Yoder:Kite Pharma: Employment, Equity Ownership. Go:Kite Pharma: Employment, Equity Ownership; Amgen: Equity Ownership. Rosenberg:Kite Pharma: Other: CRADA between Surgery Branch-NCI and Kite Pharma. Wiezorek:Kite Pharma: Employment, Equity Ownership, Other: Officer of Kite Pharma. Roberts:Kite Pharma: Employment, Equity Ownership, Other: Officer of Kite Pharma. Chang:Kite Pharma: Employment, Equity Ownership, Other: Officer of Kite Pharma. Bot:Kite Pharma: Employment, Equity Ownership.

scholarly journals Clinical Response in Relapsed/Refractory (R/R) B-NHL Treated with the CD19-Directed CAR T-Cell Product JWCAR029

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2876-2876 ◽  
Author(s):  
Zhitao Ying ◽  
Pengpeng Xu ◽  
Li Wang ◽  
Shu Cheng ◽  
Wen Wu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Dose Level ◽  
Employment Equity ◽  
Car T Cells ◽  
Car T Cell ◽  
Non Hodgkin Lymphoma ◽  
Car T ◽  
Equity Ownership

Introduction JWCAR029 is a CD19-directed 4-1BB chimeric antigen receptor (CAR) T cell product with a 4-1BB costimulatory domain, of which CD4 and CD8 CAR T cells are produced together and transfused in non-fixed ratio. We conducted a single arm, open-label, dose escalation Phase I trial of JWCAR029 in relapsed and refractory B-cell non-Hodgkin lymphoma (NCT03344367 and NCT03355859). Methods Eligible pts had confirmed B-cell NHL with R/R disease after ≥2 prior lines of therapy. All subjects received lymphodepleting chemotherapy prior to receiving JWCAR029. After lymphodepleting chemotherapy, JWCAR029 was administrated as a single infusion in escalating dose levels, from 25×106 CAR T cells (dose level 1, DL1), 50×106 CAR T cells (dose level 2, DL2), 100×106 CAR T cells (dose level 3, DL3) to 150×106 CAR T cells (dose level 4, DL4) according to mTPI-2 algorithm. Circulating blood counts, serum biochemistry, coagulation status, and cytokines were followed up after infusion. Cytokines were assessed on a Luminex platform. Tumor evaluation was evaluated per the Lugano criteria by PET-CT (Cheson, 2014) and safety and disease status was followed at approximately 1, 3, 6, 9, 12, 18 and 24 months after receiving JWCAR029. PK was measured by flow cytometry and real-time quantitative polymerase chain reaction system. All the adverse events were recorded for 24 months after infusion. The study was approved by Beijing Cancer Hospital and Shanghai Rui Jin Hospital Review Board with informed consent obtained in accordance with the Declaration of Helsinki. Results As of July 5, 2019, 44 patients were screened and 32 patients were enrolled and received treatment in two study sites in China. Twenty nine patients are evaluable and have been followed for at least 6 months: 20 diffuse large B cell lymphoma (DLBCL) and 9 follicular lymphoma, mantle cell lymphoma and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue lymphoma. Median age was 52 years (range 29 to 68 years). The demographic characteristics of the patients are shown in Table 1. All patients received immunochemotherapy as induction and a median of four lines of salvage treatment (range 2 to 7). Eleven (34%) patients received bridging chemotherapy after T cell collection due to rapid tumor progression, followed by re-evaluation before CAR T cell infusion. Lymphodepletion consisted of fludarabine 25mg/m2/d and cyclophosphamide 250mg/m2/d on Day -4 to Day -2, followed by CAR T cell infusion on Day 0. Median time to peak CAR+ T cell expansion was 11 (8-15) days. No DLTs were reported. There were no treatment-related deaths. Seventeen patients (53.1%) reported cytokine release syndrome (CRS) with 16 grade 1 or 2 (50%) and 1 (3.1%) grade 3. No grade 4 or 5 CRS was observed. Main symptoms were fever (>39.0 degrees), fatigue, and muscle soreness. The rate of CRS was similar across dose level groups. Grade 1 and 2 neurotoxicity was observed in 5 patients (15.6%). No grade ≥3 neurotoxicity was reported. Most common adverse events (frequency >20%) included leukopenia (Gr 3-4: 21.9%, Gr 1-2: 43.8%), lymphopenia (Gr 1-2: 21.9%, Gr 3-4: 21.9%), neutropenia (Gr 1-2: 37.5%, Gr 3-4: 28.2%), thrombocytopenia (Gr 1-2: 21.9%, Gr 3-4: 3.1%), pyrexia (Gr 1-2: 21.9%) and immunoglobulins decreased (Gr 1: 28.1%). Among all 29 efficacy-evaluable patients (6 of DL1, 6 of DL2, 8 of DL3 and 9 of DL4), the best ORR was 89.7%; 85% for DLBCL patients. ORR/CRR of all evaluable patients at 1, 3 and 6 months were 86.2%/65.5%, 69%/62.1% and 58.6%/55.2%, respectively, and for the 20 DLBCL patients the ORR/CRR was 80%/60%, 55%/55%, and 45%/45%, respectively (Table 2). Conclusion Although longer follow-up is needed, the data from 29 evaluable patients in this Phase I trial have demonstrated high response rates and a favorable safety profile of JWCAR029 in relapsed and refractory B-cell non-Hodgkin lymphoma. A Ph II trial that further assess safety and efficacy of JWCAR029 in DLBCL and FL patients has been initiated and is open for enrollment. Disclosures Wang: JW therapeutics (Shanghai) Co., Ltd: Employment, Equity Ownership. Hao:JW therapeutics (Shanghai) Co., Ltd: Employment, Equity Ownership. Yang:JW therapeutics (Shanghai) Co., Ltd: Employment, Equity Ownership. Lam:JW therapeutics (Shanghai) Co., Ltd: Employment, Equity Ownership. Li:JW therapeutics (Shanghai) Co., Ltd: Employment, Equity Ownership. Zheng:JW therapeutics (Shanghai) Co., Ltd: Employment, Equity Ownership.

scholarly journals Identification of Potent CD19 scFv for CAR T Cells through scFv Screening with NK/T-Cell Line

2020 ◽  
Vol 21 (23) ◽  
pp. 9163
Author(s):  
Chung Hyo Kang ◽  
Yeongrin Kim ◽  
Heung Kyoung Lee ◽  
So Myoung Lee ◽  
Hye Gwang Jeong ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cell Line ◽  
Cell Lines ◽  
Jurkat Cell ◽  
Single Chain ◽  
Car T Cells ◽  
Car T ◽  
Nk T Cell

CD19 is the most promising target for developing chimeric-antigen receptor (CAR) T cells against B-cell leukemic cancer. Currently, two CAR-T-cell products, Kymriah and Yescarta, are approved for leukemia patients, and various anti-CD19 CAR T cells are undergoing clinical trial. Most of these anti-CD19 CAR T cells use FMC63 single-chain variable fragments (scFvs) for binding CD19 expressed on the cancer cell surface. In this study, we screened several known CD19 scFvs for developing anti-CD19 CAR T cells. We used the KHYG-1 NK/T-cell line for screening of CD19 scFvs because it has advantages in terms of cell culture and gene transduction compared to primary T cells. Using our CAR construct backbone, we made anti-CD19 CAR constructs which each had CD19 scFvs including FMC63, B43, 25C1, BLY3, 4G7, HD37, HB12a, and HB12b, then made each anti-CD19 CAR KHYG-1 cells. Interestingly, only FMC63 CAR KHYG-1 and 4G7 CAR KHYG-1 efficiently lysed CD19-positive cell lines. In addition, in Jurkat cell line, only these two CAR Jurkat cell lines secreted IL-2 when co-cultured with CD19-positive cell line, NALM-6. Based on these results, we made FMC63 CAR T cells and 4G7 CAR T cells from PBMC. In in vitro lysis assay, 4G7 CAR T cells lysed CD19-positive cell line as well as FMC63 CAR T cells. In in vivo assay with NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice, 4G7 CAR T cells eradicated NALM-6 as potently as FMC63 CAR T cells. Therefore, we anticipate that 4G7 CAR T cells will show as good a result as FMC63 CAR T cells for B-cell leukemia patients.

scholarly journals Multiplexed Immunofluorescence (IF) Analysis and Gene Expression Profiling of Biopsies from Patients with Relapsed/Refractory (R/R) Diffuse Large B Cell Lymphoma (DLBCL) Treated with Lisocabtagene Maraleucel (liso-cel) in Transcend NHL 001 Reveal Patterns of Immune Infiltration Associated with Durable Response

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 202-202 ◽  
Author(s):  
David J. Reiss ◽  
Trevor Do ◽  
David Kuo ◽  
Vanessa E. Gray ◽  
N. Eric Olson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Employment Equity ◽  
Durable Response ◽  
Car T Cells ◽  
Car T Cell ◽  
Lower Baseline ◽  
Car T ◽  
Equity Ownership

Background: The availability of chimeric antigen receptor (CAR)-modified T cells (CAR T) has profoundly increased therapeutic options for patients (pts) with B cell malignancies, including DLBCL. Liso-cel is an investigational, anti-CD19, defined composition, 4-1BB, CAR T cell product administered at a target dose of CD4+ and CD8+ CAR T cells. To understand tumor microenvironmental (TME) factors affecting short-term and durable responses in pts with R/R DLBCL who received liso-cel in the TRANSCEND NHL 001 study, we conducted multiplexed IF analyses of 111 DLBCL biopsies for 83 pts obtained at baseline (n=58) and approximately 11 days (D11) (n=53; 28 paired) after liso-cel infusion (NCT02631044). Methods: We employed three 5-plex IF panels, consisting of antibodies detecting (1) B cell (CD19, CD20) and T cell lineage (CD4, CD8, EGFR) markers, (2) immunosuppressive markers (CD163, FoxP3, CD73, IDO1, PD-L1), and (3) functional markers (CD3, Ki67, GZMB, PD-1, EGFR). Liso-cel expresses a truncated EGFR (EGFRt), and fluorescent anti-EGFR was used to identify CAR T cells within the tumor biopsies. We also performed bulk tumor RNA profiling for an overlapping subset of 50 baseline biopsies and 37 D11 biopsies (11 paired). We investigated the association of differences in marker densities for pts with best overall response (BOR) of complete response (CR), and progressive disease (PD). Baseline and D11 biopsy findings were correlated with early responses at ~1 month (M1) posttreatment (PD n=16; CR n=42) and durable responses at ~9 months (M9) posttreatment (PD n=76; CR n=32; 55 pts evaluated at both M1 and M9). We investigated how baseline and D11 densities, with spatial distinction between tumoral and peritumoral regions, correlated with early and durable responses. All comparisons describe differences in median densities, and have statistical significance reported with uncorrected P values assessed via the (unpaired) Wilcoxon-Mann-Whitney nonparametric test. Results: Signals in baseline biopsies that correlated with early (M1) response differed from those that correlated with durable (M9) CR. A 21% higher baseline presence of PD-1+ T cells was associated with pts who achieved early CR at M1 vs pts who had PD at M1 (P=0.007). Pts with durable CR at M9 had 39% lower baseline levels of CD163+ macrophages (P=0.019) and 270% higher levels of CD73+ cells (P=0.028) than those with PD at M9. On-treatment (D11) tumors of pts with both early and durable CR had 28% higher levels of EGFRt+ (CAR T) CD8+ T cells (P=0.022), and 810% higher EGFRt- (non-CAR T) CD4+ (but notably, not CD8+; P=0.28) T cells (P=0.009). We also investigated changes in marker densities between baseline and on-treatment (D11) biopsies, and found that pts with durable CR at M9 had decreased on-treatment B cell densities (P=0.029), and increased densities of CD8+ GZMB+, Ki67+, and/or PD-1+ CAR (P=0.001) as well as non-CAR T (P=0.017) cells. Pts with durable CR also had a 29% increase in tumor-associated CD163+ macrophages at D11 relative to baseline (P=0.033). While the accessibility of spatial arrangements and multilabeled cells from IF enables a more nuanced picture of the TME, many of the general trends described above are concordant with those observed in bulk tumor RNA sequencing. Lower baseline expression of CD163 (P=0.021) and higher expression of CD73 (P=0.054) were seen in pts with durable CR. Additionally, elevated on-treatment (D11) expression of CD3E, CD4, and liso-cel (P&lt;0.001) supports the IF finding of greater endogenous and CAR T cell infiltration in pts who responded to treatment. Moreover, pts with a CR at M9 had increased CD163 expression measured at D11 relative to baseline (P&lt;0.001). Conclusions: Overall, these data suggest that increased infiltration of tumor-specific CAR T cells upon initial treatment with liso-cel helped establish an active immune response, and that recruitment of additional functional endogenous (particularly CD4+) T cells correlated with durable response. Higher numbers of activated/functional T cells and lower numbers of macrophages prior to treatment also correlated with durable response to liso-cel. Thus, tumors in responders may already have had a baseline TME in which T cells could infiltrate and respond to antigen. This may have promoted the success of CAR T cell entry into tumors and the subsequent recruitment and activation of endogenous lymphocytes that support their function. Disclosures Reiss: Celgene Corporation: Employment, Equity Ownership. Do:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Kuo:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Gray:Celgene Corporation: Employment, Equity Ownership. Olson:Celgene Corporation: Employment, Equity Ownership. Lee:Celgene Corporation: Employment, Equity Ownership. Young:Celgene Corporation: Employment, Equity Ownership. Srinivasan:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Gray:Celgene: Employment, Equity Ownership. Fox:Celgene Corporation: Employment, Equity Ownership. Couto:Celgene Corporation: Employment, Equity Ownership. Dubovsky:Celgene: Employment. Schmitz:Celgene Corporation: Employment, Equity Ownership. Newhall:Celgene Corporation: Employment, Equity Ownership.

scholarly journals Statistical Learning Approaches for Predicting Lisocabtagene Maraleucel (liso-cel) Drug Product Composition from Donor-Selected Material Composition

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 591-591 ◽  
Author(s):  
Yue Jiang ◽  
Afshin Mashadi-Hossein ◽  
Rachel Yost ◽  
Jeffrey Teoh ◽  
Ryan P. Larson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Drug Product ◽  
Starting Material ◽  
Lasso Regression ◽  
Employment Equity ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Equity Ownership

Introduction: Liso-cel is an investigational, anti-CD19, defined composition (4-1BB) chimeric antigen receptor (CAR) T cell product administered at a target dose of CD4+ and CD8+ CAR T cells. Liso-cel manufacturing process design includes controls that minimize between-lot variability, enabling robust CAR T cell generation across heterogeneous patient populations and disease indications. Characterization of liso-cel includes measurements of cell health, phenotype, and function. To demonstrate the robustness of the manufacturing process for which a contributor of variation is variability in incoming patient material, we developed a statistical method leveraging canonical correlation analysis (CCA) and lasso regression for predicting CAR T cell composition from measurements of cell health and phenotype in incoming patient T cells. These methods may also improve our understanding of donor variability effects on CAR T cell quality. Methods: CAR T cells were manufactured from autologous leukapheresis material in the TRANSCEND NHL 001 (NCT02631044) clinical trial. CCA and lasso models were constructed from 34 starting material attributes and 101 CD4 and CD8 clinical drug product attributes from 119 patients. CCA was implemented using prospective meta-analysis and telefit packages, and lasso regression was implemented using the glmnet package, both in R v3.5. Predictive accuracy was assessed for both methods using ten-fold cross validation. Results: CCA simultaneously found linear combinations of incoming patient T cell attributes and linear combinations of drug product attributes such that their correlation was maximized with an option of evoking a sparsity "penalty" to reduce model complexity by down-weighting (regularizing) attributes with small, independent effects. This approach enabled us to identify "meta-features" of primary components of incoming T cells strongly correlated with those of CAR T cells. Meta-feature 1 indicated that proportions of naïve CD4 T cells in starting T cell material were highly correlated with frequencies of naïve-like CD4 and CD8 CAR T cells post manufacturing (Figure 1). Meta-feature 2 revealed that naïve and central memory CD4 and CD8 T cell proportions in starting materials were correlated with naïve and central memory CD8 CAR T cells. Meta-feature 3 indicated that effector CD4 T cell proportions measured phenotypically in starting material were correlated with CD4 and CD8 CAR T cell effector functions, including antigen-specific cytokine production. Lastly, meta-feature 4 suggested that effector CD8 T cell proportions in starting material were correlated with CD8 CAR T cell effector functions. Because penalized CCA identified primary components of features correlated between incoming patient T cell material and manufactured CAR T cells, it can predict multiple attributes simultaneously, but with reduced capacity to most effectively predict a single attribute of interest. Hence, we implemented the lasso regression method that performs both variable selection and regularization to enhance the predictive accuracy of single attributes one at a time. Lasso regression models predict subsets of CAR T cell attributes more accurately than CCA and identify which starting T cell attributes are most important for prediction at the expense of having less power for predicting drug product attributes with limited relevant individual features in starting material. CCA achieved prediction accuracies up to an R2 of 42% for predicting CD4+ CAR+ naïve-like T cells (P=0.008), whereas lasso regression achieved up to an R2 of 67% for the same CAR T cell attribute (P=6×10-275). Both methods perform best at predicting classically naïve and TEMRA T cell compositions. Using CCA and lasso, we achieved nominally significant predictions for 53 of the 101 CAR T cell attributes using only 34 starting material attributes as input; the residual variation in the CAR T cell attributes independent of starting material composition was likely due to other patient or process variables. Conclusion: The application of statistical learning approaches to CAR T cell characterization data can enable us to predict CAR T cell characteristics that are directly related to donor-to-donor variability in incoming T cell material. These methods may allow us to develop adaptive manufacturing processes to improve treatment outcomes of autologous cellular therapies. Disclosures Jiang: Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Mashadi-Hossein:Celgene Corporation: Employment, Equity Ownership. Yost:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Teoh:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Larson:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership. Hause:Juno Therapeutics, a Celgene Company: Employment, Equity Ownership.

scholarly journals Preclinical Evaluation of ALLO-819, an Allogeneic CAR T Cell Therapy Targeting FLT3 for the Treatment of Acute Myeloid Leukemia

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3921-3921 ◽  
Author(s):  
Cesar Sommer ◽  
Hsin-Yuan Cheng ◽  
Yik Andy Yeung ◽  
Duy Nguyen ◽  
Janette Sutton ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Target Cells ◽  
Employment Equity ◽  
T Cell Therapy ◽  
Cell Therapies ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Equity Ownership

Autologous chimeric antigen receptor (CAR) T cells have achieved unprecedented clinical responses in patients with B-cell leukemias, lymphomas and multiple myeloma, raising interest in using CAR T cell therapies in AML. These therapies are produced using a patient's own T cells, an approach that has inherent challenges, including requiring significant time for production, complex supply chain logistics, separate GMP manufacturing for each patient, and variability in performance of patient-derived cells. Given the rapid pace of disease progression combined with limitations associated with the autologous approach and treatment-induced lymphopenia, many patients with AML may not receive treatment. Allogeneic CAR T (AlloCAR T) cell therapies, which utilize cells from healthy donors, may provide greater convenience with readily available off-the-shelf CAR T cells on-demand, reliable product consistency, and accessibility at greater scale for more patients. To create an allogeneic product, the TRAC and CD52 genes are inactivated in CAR T cells using Transcription Activator-Like Effector Nuclease (TALEN®) technology. These genetic modifications are intended to minimize the risk of graft-versus-host disease and to confer resistance to ALLO-647, an anti-CD52 antibody that can be used as part of the conditioning regimen to deplete host alloreactive immune cells potentially leading to increased persistence and efficacy of the infused allogeneic cells. We have previously described the functional screening of a library of anti-FLT3 single-chain variable fragments (scFvs) and the identification of a lead FLT3 CAR with optimal activity against AML cells and featuring an off-switch activated by rituximab. Here we characterize ALLO-819, an allogeneic FLT3 CAR T cell product, for its antitumor efficacy and expansion in orthotopic models of human AML, cytotoxicity in the presence of soluble FLT3 (sFLT3), performance compared with previously described anti-FLT3 CARs and potential for off-target binding of the scFv to normal human tissues. To produce ALLO-819, T cells derived from healthy donors were activated and transduced with a lentiviral construct for expression of the lead anti-FLT3 CAR followed by efficient knockout of TRAC and CD52. ALLO-819 manufactured from multiple donors was insensitive to ALLO-647 (100 µg/mL) in in vitro assays, suggesting that it would avoid elimination by the lymphodepletion regimen. In orthotopic models of AML (MV4-11 and EOL-1), ALLO-819 exhibited dose-dependent expansion and cytotoxic activity, with peak CAR T cell levels corresponding to maximal antitumor efficacy. Intriguingly, ALLO-819 showed earlier and more robust peak expansion in mice engrafted with MV4-11 target cells, which express lower levels of the antigen relative to EOL-1 cells (n=2 donors). To further assess the potency of ALLO-819, multiple anti-FLT3 scFvs that had been described in previous reports were cloned into lentiviral constructs that were used to generate CAR T cells following the standard protocol. In these comparative studies, the ALLO-819 CAR displayed high transduction efficiency and superior performance across different donors. Furthermore, the effector function of ALLO-819 was equivalent to that observed in FLT3 CAR T cells with normal expression of TCR and CD52, indicating no effects of TALEN® treatment on CAR T cell activity. Plasma levels of sFLT3 are frequently increased in patients with AML and correlate with tumor burden, raising the possibility that sFLT3 may act as a decoy for FLT3 CAR T cells. To rule out an inhibitory effect of sFLT3 on ALLO-819, effector and target cells were cultured overnight in the presence of increasing concentrations of recombinant sFLT3. We found that ALLO-819 retained its killing properties even in the presence of supraphysiological concentrations of sFLT3 (1 µg/mL). To investigate the potential for off-target binding of the ALLO-819 CAR to human tissues, tissue cross-reactivity studies were conducted using a recombinant protein consisting of the extracellular domain of the CAR fused to human IgG Fc. Consistent with the limited expression pattern of FLT3 and indicative of the high specificity of the lead scFv, no appreciable membrane staining was detected in any of the 36 normal tissues tested (n=3 donors). Taken together, our results support clinical development of ALLO-819 as a novel and effective CAR T cell therapy for the treatment of AML. Disclosures Sommer: Allogene Therapeutics, Inc.: Employment, Equity Ownership. Cheng:Allogene Therapeutics, Inc.: Employment, Equity Ownership. Yeung:Pfizer Inc.: Employment, Equity Ownership. Nguyen:Allogene Therapeutics, Inc.: Employment, Equity Ownership. Sutton:Allogene Therapeutics, Inc.: Employment, Equity Ownership. Melton:Allogene Therapeutics, Inc.: Employment, Equity Ownership. Valton:Cellectis, Inc.: Employment, Equity Ownership. Poulsen:Allogene Therapeutics, Inc.: Employment, Equity Ownership. Djuretic:Pfizer, Inc.: Employment, Equity Ownership. Van Blarcom:Allogene Therapeutics, Inc.: Employment, Equity Ownership. Chaparro-Riggers:Pfizer, Inc.: Employment, Equity Ownership. Sasu:Allogene Therapeutics, Inc.: Employment, Equity Ownership.

Direct Comparison of In Vivo Fate of Second and Third-Generation CD19-Specific Chimeric Antigen Receptor (CAR)-T Cells in Patients with B-Cell Lymphoma: Reversal of Toxicity from Tonic Signaling

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1851-1851 ◽  
Author(s):  
Diogo Gomes da Silva ◽  
Malini Mukherjee ◽  
Madhuwanti Srinivasan ◽  
Olga Dakhova ◽  
Hao Liu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
2Nd Generation ◽  
Car T Cells ◽  
Car T ◽  
Equity Ownership

Abstract Although adoptive transfer of T cells with second-generation CD19-specific CARs containing CD28 or 4-1BB costimulatory endodomains shows remarkable clinical efficacy against B cell malignancies, the optimal choice of costimulatory domains in these and other CARs remains controversial. Depending on the precise CAR structure and specificity, individual endodomains may be associated with deleterious ligand-independent tonic signaling in the transduced T cell. Long et al. (Nat Med 2015) established the CD28 co-stimulatory endodomain can have a toxic tonic signaling effect, but it is unclear if tonic 4-1BB signaling may have deleterious consequences as well, and if such effects can be reversed. We therefore modeled tonic CAR signaling in T cells by transducing them with gammaretroviral vectors expressing 2nd-generation CD19.CAR constructs containing either the CD28 or 4-1BB costimulatory endodomain (in addition to the CD3-ζ chain endodomain). Compared to CAR-T cells with the CD28 endodomain alone, those with 4-1BB alone expanded 70% more slowly following transduction. Impaired expansion of 4-1BB CD19.CAR-T cells was coupled with a 4-fold increase in apoptosis and a gradual downregulation of CAR expression, and was a consequence of 4-1BB-associated tonic TRAF2-dependent signaling, leading to activation of NF-κB, upregulation of Fas and augmented Fas-dependent activation-induced T cell death (AICD). Moreover, expression of 4-1BB CAR from a gammaretroviral vector increased tonic signaling through a self-amplifying/positive feedback effect on the retroviral LTR promoter. Because of the toxicity of 4-1BB in our gammaretroviral CAR.CD19 construct (manifest by delayed expansion and increased apoptosis) we could not directly compare the in vivo fate of T cells expressing CAR.CD19 4-1BB with that of co-administered CAR.CD19 CD28 T cells in patients with lymphoma. We found, however, that the adverse effects of tonic 4-1BB costimulation could be overcome in a 3rd-generation CAR.CD19 vector, containing both CD28 and 4-1BB costimulatory molecules in tandem. We thus compared the fate of a 3rd-generation vector containing both CD28 and 4-1BB costimulatory domains with that of a 2nd-generation vector containing CD28 alone. Six patients with refractory/relapsed diffuse large B-cell lymphoma received 2 cell populations, one expressing 2nd and one expressing 3rd generation vectors. To determine whether CD28 alone was optimal (which would suggest 4-1BB is antagonistic) or whether 4-1BB had an additive or synergistic effect contributing to superior persistence and expansion of the CD28-41BB combination, patients were simultaneously infused with 1-20×106 of both 2nd and 3rd generation CAR+ T cells/m2 48-72 hours after lymphodepletion with cyclophosphamide (500 mg/m2/d) and fludarabine (30 mg/m2/d) × 3. Persistence of infused T cells was assessed in blood by CD19.CAR qPCR assays specific for each CAR. Molecular signals peaked approximately 2 weeks post infusion, remaining detectable for up to 6 months. The 3rd-generation CAR-T cells had a mean 23-fold (range 1.1 to 109-fold) higher expansion than 2nd-generation CAR-T cells and correspondingly longer persistence. Two patients had grade 2 cytokine release syndrome, with elevation of proinflammatory cytokines, including IL-6, at the time of peak expansion of T cells. Of the 5 patients evaluable for response, 2 entered complete remission (the longest ongoing for 9 months), 1 has had continued complete remission after autologous stem cell transplantation, 1 had a partial response, and 1 progressed. In conclusion, our data indicate that infusion of T cells carrying a CD19.CAR containing CD28 and 4-1BB endodomains is safe and can have efficacy at every dose level tested. Additionally, in a side-by-side comparison, the 3rdgeneration vector produced greater in vivo expansion and persistence than an otherwise identical CAR-T cell population with CD28 alone. Disclosures Rooney: Cell Medica: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Viracyte: Equity Ownership. Heslop:Celgene: Patents & Royalties, Research Funding; Chimerix: Other: Endpoint adjudication committee; Viracyte: Equity Ownership; Cell Medica: Patents & Royalties: Licensing agreement EBV-specific T cells.

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