scholarly journals First Results from the Dose Escalation Segment of the Phase I Clinical Study Evaluating Cyad-02, an Optimized Non Gene-Edited Engineered NKG2D CAR T-Cell Product, in Relapsed or Refractory Acute Myeloid Leukemia and Myelodysplastic Syndrome Patients

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 36-36 ◽  
Author(s):  
Dries Deeren ◽  
Johan A. Maertens ◽  
Tara Lin ◽  
Yves Beguin ◽  
Benjamin Demoulin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Phase I ◽  
Research Funding ◽  
Next Generation ◽  
Cell Product ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Background T-cells engineered to express a chimeric antigen receptor (CAR) based on the NKG2D receptor (NKG2D CAR) targeting the 8 NKG2D ligands (MICA/B, ULBP1-6) over-expressed by a large variety of malignancies have been developped to treat patients, including patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Previously, CYAD-01, the first generation of NKG2D CAR T-cell products, was evaluated in several Phase I clinical trials and showed initial signals of objective clinical responses in patients with r/r AML and MDS, albeit with short durability. Preclinical data have shown that NKG2D ligands MICA and MICB are transiently upregulated on activated CAR T-cells, and target-dependent killing of CAR T-cells post-infusion can potentially occur, leading to short in vivo persistence. In an effort to increase the persistence and potency of the NKG2D CAR T-cells, CYAD-02 was developed as a next-generation product using a non-gene editing approach to silence the expression of MICA and MICB. Aim MICA and MICB were down-regulated by inserting a single optimized short hairpin RNA (shRNA) targeting both MICA and MICB within the NKG2D CAR construct. This next-generation NKG2D CAR T-cell product is manufactured with the OptimAb process, resulting in CAR T-cells with a higher frequency of early memory T-cells secreting high levels of cytokines upon activation, and is referred to as CYAD-02. Results As compared to CYAD-01, CYAD-02 cell expansion in vitro was 3-fold increased. In an in vivo AML model, CYAD-02 showed 10-fold higher engraftment 1 week after injection and improved anti-tumor activity as compared to CYAD-01 manufactured with the initial mAb process. This led to a 2.6-fold increase of mouse survival as compared to CYAD-01 in a stress-test aggressive AML model where the dose of CYAD-01 was titrated down for minimal activity (figure). The first-in-human study evaluating CYAD-02, the CYCLE-1 study (NCT04167696), has been initiated in early 2020 in patients with r/r AML/MDS. The study evaluates three dose-levels of CYAD-02 (1x108, 3x108 and 1x109 cells/infusion), administered as a single infusion after non-myeloablative preconditioning chemotherapy (cyclophosphamide 300 mg/m²/day and fludarabine 30 mg/m²/day, daily for 3 days, CyFlu) according to a classical Fibonacci 3+3 design. As of August 2020, 6 patients have been treated with CYAD-02 at the dose of 1x108 or 3x108 cells/infusion. To date, the results demonstrate the safety and tolerability for CYAD-02 in patients with r/r AML and MDS with no dose-limiting toxicity observed. The study is currently enrolling at 1x109 cells/infusion. The CYAD-02 safety profile and preliminary clinical activity data together with the pharmacokinetics evaluation from the complete dose escalation segment will be provided at the time of presentation. Conclusion/summary The CYAD-02 is the first autologous CAR T-cell product based on the non-gene edited shRNA technology used to treat patients. This next generation NKG2D CAR T-cell product is currently investigated in the CYCLE-1 Phase I study in r/r AML/MDS patient population, a difficult to target disease due in part to the absence of truly AML-specific surface antigens, its rapid clinical progression and the absence of disease control by the CyFlu preconditioning. Both the anti-MICA and MICB shRNA hairpin and the OptimAb manufacturing process for CYAD-02 aim to improve CAR T-cell persistence and clinical responses. Figure Disclosures Lin: Mateon Therapeutics: Research Funding; Aptevo: Research Funding; Abbvie: Research Funding; Ono Pharmaceutical: Research Funding; Incyte: Research Funding; Gilead Sciences: Research Funding; Jazz: Research Funding; Astellas Pharma: Research Funding; Bio-Path Holdings: Research Funding; Celgene: Research Funding; Celyad: Research Funding; Genetech-Roche: Research Funding; Seattle Genetics: Research Funding; Tolero Pharmaceuticals: Research Funding; Trovagene: Research Funding; Prescient Therapeutics: Research Funding; Pfizer: Research Funding. Demoulin:Celyad Oncology: Current Employment. Fontaine:Celyad Oncology: Current Employment. Sotiropoulou:Celyad Oncology: Current Employment. Alcantar-Orozco:Celyad Oncology: Current Employment. Breman:Celyad Oncology: Current Employment. Dheur:Celyad Oncology: Current Employment. Braun:Celyad Oncology: Current Employment. Lonez:Celyad Oncology: Current Employment. Gilham:Celyad Oncology: Current Employment. Flament:Celyad Oncology: Current Employment. Lehmann:Celyad Oncology: Current Employment.

scholarly journals Next Generation NKG2D-based CAR T-cells (CYAD-02): Co-expression of a Single shRNA Targeting MICA and MICB Improves Cell Persistence and Anti-Tumor Efficacy in vivo

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3931-3931
Author(s):  
Martina Fontaine ◽  
Benjamin Demoulin ◽  
Simon Bornschein ◽  
Susanna Raitano ◽  
Steve Lenger ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Next Generation ◽  
Activated T Cells ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Anti Tumor Activity ◽  
Nkg2d Receptor

Background The Natural Killer Group 2D (NKG2D) receptor is a NK cell activating receptor that binds to eight different ligands (NKG2DL) commonly over-expressed in cancer, including MICA and MICB. The product candidate CYAD-01 are chimeric antigen receptor (CAR) T-cells encoding the full length human NKG2D fused to the intracellular domain of CD3ζ. Data from preclinical models have shown that CYAD-01 cells specifically target solid and hematological tumors. Encouraging preliminary results from the Phase I clinical trial THINK, assessing CYAD-01 safety, showed initial signals of objective clinical responses in patients with r/r AML and MDS. The clinical development of CAR T-cells has been limited by several challenges including achieving sufficient numbers of cells for clinical application. We have previously shown that NKG2D ligands are transiently expressed on activated T cells and that robust cell yields are generated through the addition of a blocking antibody and a PI3K inhibitor during cell manufacture. Here, we investigated the ability of an optimized short hairpin RNA (shRNA) technology to modulate NKG2DL expression on CYAD-01 cells and to determine if there is an increase in the anti-tumor activity of NKG2D-based CAR T-cells (termed CYAD-02). Methods Molecular and cellular analyses identified MICA and MICB as the key NKG2DL expressed on activated T-cells and highly likely to participate in driving fratricide. In silico analysis and in vitro screening allowed the identification of a single shRNA targeting the conserved regions of MICA and MICB, thus downregulating both MICA and MICB expression. The selected shRNA was incorporated in the NKG2D-based CAR vector, creating the next-generation NKG2D-based CAR T-cell candidate, CYAD-02. In addition, truncated versions of the NKG2D receptor were generated to explore the mechanisms of action of NKG2D receptor activity in vivo. The in vivo persistence and anti-tumor activity of CYAD-02 cells was evaluated in an aggressive preclinical model of AML. Results Injection of CAR T-cells bearing truncated forms of the NKG2D-CAR in immunosuppressed mice resulted in similar persistence to the control T-cells. In contrast, CYAD-01 cells had reduced persistence, suggesting that the recognition of the NKG2DL by the NKG2D receptor could contribute to this effect. Analysis of cell phenotype upon CAR T-cell activation showed that MICA and MICB were transiently expressed on T-cells during manufacturing. These results collectively suggested that downregulating MICA and MICB expression in CYAD-01 cells could be a mean to increase CAR T-cell persistence in vivo. Candidate shRNA were screened for efficient targeting of both MICA and MICB at the mRNA and protein level. T-cells transduced with a single vector encoding for the NKG2D-based CAR and the selected shRNA targeting MICA and MICB (CYAD-02) demonstrated 3-fold increased expansion during in vitro culture in the absence of the blocking antibody used to increase cell yield during manufacture. When injected into immunosuppressed mice, CYAD-02 cells generated with the Optimab process showed 10-fold higher engraftment one week after injection and potent anti-tumor activity resulting in 2.6-fold increase of mouse survival in an aggressive AML model. Conclusions By using a single vector encoding the NKG2D-based CAR next to a shRNA targeting MICA and MICB and combined with improved cell culture methods, CYAD-02, the next-generation of NKG2D-based CAR T-cells, demonstrated enhanced in vivo persistence and anti-tumor activity. Following FDA acceptance of the IND application, a Phase 1 dose-escalation trial evaluating the safety and clinical activity of CYAD-02 for the treatment of r/r AML and MDS is scheduled to start in early 2020. Disclosures Fontaine: Celyad: Employment. Demoulin:Celyad: Employment. Bornschein:Celyad: Employment. Raitano:Celyad: Employment. Machado:Horizon Discovery: Employment. Moore:Avvinity Therapeutics: Employment, Other: Relationship at the time the work was performed; Horizon Discovery: Employment, Equity Ownership, Other: Relationship at the time the work was performed; Centauri Therapeutics: Consultancy, Other: Current relationship. Sotiropoulou:Celyad: Employment. Gilham:Celyad: Employment.

scholarly journals Targeting the Membrane-Proximal C2-Set Domain of CD33 for Improved CD33-Directed CAR T Cell Therapy

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2776-2776
Author(s):  
Salvatore Fiorenza ◽  
George S. Laszlo ◽  
Tinh-Doan Phi ◽  
Margaret C. Lunn ◽  
Delaney R. Kirchmeier ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Research Funding ◽  
Set Domain ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Privately Held

Abstract Background: There is increasing interest in targeting CD33 in malignant and non-malignant disorders, but available drugs are ineffective in many patients. As one limitation, therapeutic CD33 antibodies typically recognize the membrane-distal V-set domain. Likewise, currently tested CD33-directed chimeric antigen receptor (CAR) T cells likewise target the V-set domain and have thus far shown limited clinical activity. We have recently demonstrated that binding closer to the cell membrane enhances the effector functions of CD33 antibodies. We therefore raised antibodies against the membrane-proximal C2-set domain of CD33 and identified antibodies that bound CD33 regardless of the presence/absence of the V-set domain ("CD33 PAN antibodies"). Here, we tested their properties as targeting moiety in CD33 PAN CAR T cell constructs, using a clinically validated lentiviral backbone. Methods: To generate CAR T cells, negatively selected CD8 + T cells were transduced with an epHIV7 lentivirus encoding the scFv from a CD33 PAN antibody (clone 1H7 or 9G2) linked to either a short (IgG 4 hinge only), intermediate (hinge plus IgG 4 CH3 domain), or long (hinge plus IgG 4 CH3 domain plus IgG 4 CH2 domain) spacer, the CD28-transmembrane domain, CD3zeta and 4-1BB intracellular signaling domains, and non-functional truncated CD19 (tCD19) as transduction marker. Similar constructs using scFvs from 2 different V-set domain-targeting CD33 antibodies, including hP67.6 (My96; used in gemtuzumab ozogamicin), were generated for comparison. CAR-T cells were sorted, expanded in IL-7 and IL-15, and used in vitro or in vivo against human AML cell lines endogenously expressing CD33 and cell lines engineered to lack CD33 (via CRISPR/Cas9) with/or without forced expression of different CD33 variants. Results: CD33 V-set-directed CAR T cells exerted significantly more cytolytic activity against AML cells expressing an artificial CD33 variant lacking the C2-set domain (CD33 ΔE3-4) than cells expressing full-length CD33 at similar or higher levels, consistent with the notion that CD33 CAR T cell efficacy is enhanced when targeting an epitope that is located closer to the cell membrane. CD33 PAN CAR T cells were highly potent against human AML cells in a strictly CD33-dependent fashion, with constructs containing the short and intermediate-length spacer demonstrating robust cytokine secretion, cell proliferation, and in vitro cytolytic activity, as determined by 51Cr release cytotoxicity assays. When compared to optimized CD33 V-set CAR T cells, optimized CD33 PAN CAR T cells were significantly more potent in cytotoxicity, proliferation, and cytokine production without appreciably increased acquisition of exhaustion markers. In vivo, CD33 PAN CAR T cells extended survival in immunodeficient NOD.SCID. IL2rg -/- (NSG) mice bearing significant leukemic burdens from various cell line-derived xenografts (HL-60, KG1α and MOLM14) with efficient tumor clearance demonstrated in a dose-dependent fashion. Conclusion: Targeting the membrane proximal domain of CD33 enhances the anti-leukemic potency of CAR T cells. Our data provide the rationale for the further development of CD33 PAN CAR T cells toward clinical testing. Disclosures Fiorenza: Link Immunotherapeutics: Consultancy; Bristol Myers Squibb: Research Funding. Godwin: Pfizer: Research Funding; Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Turtle: Allogene: Consultancy; Amgen: Consultancy; Arsenal Bio: Consultancy; Asher bio: Consultancy; Astrazeneca: Consultancy, Research Funding; Caribou Biosciences: Consultancy, Current holder of individual stocks in a privately-held company; Century Therapeutics: Consultancy, Other; Eureka therapeutics: Current holder of individual stocks in a privately-held company, Other; Juno therapeutics/BMS: Patents & Royalties, Research Funding; Myeloid Therapeutics: Current holder of individual stocks in a privately-held company, Other; Nektar therapeutics: Consultancy, Research Funding; PACT Pharma: Consultancy; Precision Biosciences: Current holder of individual stocks in a privately-held company, Other; T-CURX: Other; TCR2 Therapeutics: Research Funding. Walter: Kite: Consultancy; Janssen: Consultancy; Genentech: Consultancy; BMS: Consultancy; Astellas: Consultancy; Agios: Consultancy; Amphivena: Consultancy, Other: ownership interests; Selvita: Research Funding; Pfizer: Consultancy, Research Funding; Jazz: Research Funding; Macrogenics: Consultancy, Research Funding; Immunogen: Research Funding; Celgene: Consultancy, Research Funding; Aptevo: Consultancy, Research Funding; Amgen: Research Funding.

scholarly journals Clinical Development of a Non-Gene-Edited Allogeneic Bcma-Targeting CAR T-Cell Product in Relapsed or Refractory Multiple Myeloma

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 27-28
Author(s):  
A. Samer Al-Homsi ◽  
Sebastien Anguille ◽  
Jason Brayer ◽  
Dries Deeren ◽  
Nathalie Meuleman ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Lines ◽  
Gene Editing ◽  
Cell Product ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Background Autologous CAR T-cell therapy targeting the B-cell maturation antigen (BCMA) has shown impressive objective response rates in patients with advanced multiple myeloma (MM). Clinical grade manufacturing of autologous CAR T-cells has limitations including vein-to-vein delivery time delay and potentially sub-optimal immunological capability of T-cells isolated from patients with advanced disease. Allogeneic CAR T-cell products, whereby cells from healthy third-party donors are used to generate an "off-the-shelf" CAR T-cell product, have the potential to overcome some of these issues. To circumvent the primary potential risk of graft-versus-host disease (GvHD) associated with the use of allogeneic T-cells, abrogation of the T-cell receptor (TCR) expression in the CAR T-cells, via gene editing, is being actively pursued. To avoid the potential safety risks and manufacturing challenges associated with gene editing, the allogeneic CYAD-211 CAR T-cell product exploits short hairpin RNA (shRNA) interference technology to down-regulate TCR expression thus avoiding the risk of life-threatening GvHD. Aim The aim is to generate a BCMA-specific allogeneic CAR T-cell product using a non-gene editing approach and study its activity both in vitro and in vivo. CYAD-211 combines a BCMA-specific CAR with a single optimized shRNA targeting the TCR CD3ζ subunit. Downregulation of CD3ζ impairs the TCR expression on the surface of the donor T-cells, preventing their reactivity with the normal host tissue cells and potential GvHD induction. Maintaining all the elements required for the therapy within a single vector (all-in-one vector) provides some significant manufacturing advantages, as a solitary selection step will isolate cells expressing all the desired traits. Results CYAD-211 cells produce high amounts of interferon-gamma (IFN-γ) during in vitro co-cultures with various BCMA-expressing MM cell lines (i.e., RPMI-8226, OPM-2, U266, and KMS-11). Cytotoxicity experiments confirmed that CYAD-211 efficiently kills MM cell lines in a BCMA-specific manner. The anti-tumor efficacy of CYAD-211 was further confirmed in vivo, in xenograft MM models using the RPMI-8226 and KMS-11 cell lines. Preclinical data also showed no demonstrable evidence of GvHD when CYAD-211 was infused in NSG mice confirming efficient inhibition of TCR-induced activation. Following FDA acceptance of the IND application, IMMUNICY-1, a first-in-human, open-label dose-escalation phase I clinical study evaluating the safety and clinical activity of CYAD-211 for the treatment of relapsed or refractory MM patients to at least two prior MM treatment regimens, is scheduled to begin recruitment. IMMUNICY-1 will evaluate three dose-levels of CYAD-211 (3x107, 1x108 and 3x108 cells/infusion) administered as a single infusion after a non-myeloablative conditioning (cyclophosphamide 300 mg/m²/day and fludarabine 30 mg/m²/day, daily for 3 days) according to a classical Fibonacci 3+3 design. Description of the study design and preliminary safety and clinical data from the first cohort will be presented at ASH 2020. Conclusion CYAD-211 is the first generation of non-gene edited allogeneic CAR T-cell product based on shRNA technology. The IMMUNICY-1 clinical study seeks to provide proof of principle that single shRNA-mediated knockdown can generate fully functional allogeneic CAR T-cells in humans without GvHD-inducing potential. We anticipate that subsequent generations of this technology will incorporate multiple shRNA hairpins within a single vector system. This will enable the production of allogeneic CAR T-cells in which multiple genes of interest are modulated simultaneously thereby providing a platform approach that can underpin the future of this therapeutic modality. Figure 1 Disclosures Al-Homsi: Celyad: Membership on an entity's Board of Directors or advisory committees. Brayer:Janssen: Consultancy; Bristol-Myers Squibb, WindMIL Therapeutics: Research Funding; Bristol-Myers Squibb, Janssen, Amgen: Speakers Bureau. Nishihori:Novartis: Other: Research support to institution; Karyopharm: Other: Research support to institution. Sotiropoulou:Celyad Oncology: Current Employment. Twyffels:Celyad Oncology: Current Employment. Bolsee:Celyad Oncology: Current Employment. Braun:Celyad Oncology: Current Employment. Lonez:Celyad Oncology: Current Employment. Gilham:Celyad Oncology: Current Employment. Flament:Celyad Oncology: Current Employment. Lehmann:Celyad Oncology: Current Employment.

Effect of chimeric antigen receptor (CAR) T cells on clonal expansion of endogenous non-CAR T cells in patients (pts) with advanced solid cancer.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 3011-3011 ◽  
Author(s):  
Rebecca H Kim ◽  
Gabriela Plesa ◽  
Whitney Gladney ◽  
Irina Kulikovskaya ◽  
Bruce L Levine ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Clonal Expansion ◽  
Time Points ◽  
Cell Product ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Vaccine Effect

3011 Background: CAR T cells have produced remarkable responses in heme malignancies, but efficacy in solid cancers is limited. Poor in vivo persistence and heterogeneous expression of the CAR target on tumors are potential barriers to the success of CAR T cell therapy. However, even with transient persistence, CAR T cells may elicit a “vaccine” effect by inducing cancer cell death and subsequent release of tumor antigens that could stimulate tumor-specific T cell activity. Methods: 6 pts with pancreatic ductal adenocarcinoma (PDAC) received repeated 3x per week intravenous (iv) infusions of mRNA-transfected mesothelin-redirected CAR T cells (CARTmeso). Pts with PDAC (n = 5), ovarian carcinoma (n = 5), and mesothelioma (n = 5) received iv infusion of lentiviral-transduced (lenti) CARTmeso with or without cyclophosphamide (Cy) preconditioning. Peripheral blood samples were collected from pts at baseline and defined time points after treatment. Genomic DNA from these samples or from pre-infused CAR T cell product was used for deep sequencing of the TCRbeta chain using the ImmunoSEQ platform. A TCRbeta clone was considered to have expanded from baseline to defined time points after treatment if it showed a two-fold change from baseline and met statistical significance by Fisher’s exact test (p < 0.05). Results: mRNA CARTmeso cells persisted in vivo for < 24 hrs. Unexpectedly, therapy induced clonal T cell expansion detected in the blood by day 14 in all 6 pts. Expanded clones underwent contraction by day 28 in 3 pts. In one pt, peripherally expanded clones were also detected in a tumor biopsy, but without significant intratumoral clonal expansion. Lenti CARTmeso therapy also induced peripheral expansion of T cell clones both present and not present in the infused CAR T cell product. However, with Cy preconditioning, clonal expansion seen after lenti CARTmeso therapy was predominately restricted to clones detected in the CAR T cell product. Conclusions: In pts with advanced solid cancers, CARTmeso stimulates clonal expansion of endogenous T cells, which is lost with Cy conditioning. Findings suggest that CAR T cells may elicit a “vaccine” effect with potential therapeutic implications.

Efficacy of SCRI-CAR19x22 T cell product in B-ALL and persistence of anti-CD22 activity.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 3035-3035
Author(s):  
Rebecca Alice Gardner ◽  
Colleen Annesley ◽  
Ashley Wilson ◽  
Corinne Summers ◽  
Prabha Narayanaswamy, ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Product ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Grade 3 ◽  
Dose Levels ◽  
Negative Population

3035 Background: Loss of CD19 expression is a major cause of limited durable B-ALL remission following CD19 CAR T cells, which might be overcome by utilization of dual CD19xCD22 CAR T cell targeting. Methods: A Phase I trial (NCT03330691) of SCRI-CAR19x22 was developed using dual transduction of lentiviral vectors encoding for either a CD19- or CD22-specific CAR T cell construct, both with 4-1BB co-stimulation. Manufacturing was performed in a closed G-Rex system with IL-7, IL-15 and IL-21. After lymphodepletion, CAR T cells were infused at 1 or 3 X 106 CAR T cells/kg dose levels. Leukemic response and CAR T cell persistence were evaluated by flow cytometry. Results: Products were successfully manufactured in all 28 enrolled subjects with 7.92 average days in culture (range of 7-11 days) and consisted of an average CD8:CD4 ratio of 3.09 (range 0.19 to 8.9). The cellular product CAR composition was 29% CD19, 31% CD22 and 39% CD19 and CD22 targeting. 13 subjects had prior exposure to CD19 or CD22 targeting therapies with diverse expression of CD19 and CD22 on the leukemic blasts. No dose limiting toxicities occurred in the 27 infused subjects. The recommended phase 2 dose is 3 x 106 CAR+ cells/kg. CRS was present in 80% of subjects, with 85% of CRS being grade 2 or less, and a peak grade of 3 (n = 3). Mild neurotoxicity occurred in 38%, with a single grade 3 event. 84.6% obtained a CR, of which 95% were MRD negative. Of the 4 subjects who did not achieved a CR, 2 had a pre-existing CD19 negative population and one had previously received CAR T cells and rejected SCRI-CAR19x22. There have been 4 relapses with varying CD19 and CD22 expression as follows: 1 CD19-CD22-, 1 CD19+CD22+, and 2 CD19-CD22+. The in vivo engraftment of CAR T cells peaked most frequently between day +7 and +14 and was predominated by the CD19 CAR+ T cells. Conclusions: We demonstrate manufacturing feasibility and safety of SCRI-CAR19x22. While initial efficacy is demonstrated, CD22 activity is poor due to limited expansion of the CD22 CAR-containing components and subjects with pre-existing CD19 negative leukemia fared poorly. Development of a revised CD22 CAR that exhibits a reduction tonic signaling is underway, with plans to explore the new construct in the context of a dual-targeting CD19xCD22 CAR T cell product. Clinical trial information: NCT03330691 .

scholarly journals Repurposing Bi-Specific Chimeric Antigen Receptor (CAR) Approach to Enhance CAR T Cell Activity Against Low Antigen Density Tumors

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1727-1727
Author(s):  
Sherly Mardiana ◽  
Olga Shestova ◽  
Stephan A. Grupp ◽  
Marco Ruella ◽  
David M. Barrett ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Line ◽  
Tumor Cells ◽  
Therapeutic Efficacy ◽  
Research Funding ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Abstract BACKGROUND Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of relapsed/refractory B-cell malignancies, as highlighted by high complete remission rates and FDA approval of CD19-specific CAR T cell products. However, depth and duration of remission are limited by antigen loss/downregulation on tumors, as observed in clinical trials using CAR T cells targeting the CD19 or CD22 in leukemia and lymphoma, BCMA in multiple myeloma, and EGFRvIII in glioblastoma. This observation forms the basis of current efforts to develop multi-targeting CAR T cells to prevent antigen-negative escape. Antigen density is an important factor modulating CAR T cell response, since antigen expression below a certain threshold fails to trigger the full range of T cell functions. Given that signal strength induced upon antigen encounter determines CAR T cell activity, we hypothesized that simultaneous targeting of two dimly-expressed antigens will result in enhanced CAR T cell signaling and anti-tumor function, approaching that seen in response to one highly-expressed antigen. This is important given the heterogeneity of antigen expression in various cancers. Therefore, the bi-specific CAR T cells currently being developed to prevent antigen-negative escape could also be used to enhance efficacy against low antigen density (LAD) tumors. Results from this study will provide a novel rationale for using multi-specific CAR T cells and illuminate the mechanisms of successful CAR T cell therapy. METHODS Lentivirus transduction was performed to generate CAR T cells from healthy human T cells, using second generation 4-1BBz CARs specific for either human CD19 or CD22, or both in cis, herein referred to as CAR19, CAR22, or CAR19/22, respectively (Figure 1A). For in vitro functional characterization, we performed co-culture assay of T cells and B cell leukemia cell line NALM6, which is known to express high levels of both CD19 and CD22. To assess T cell function against LAD tumor cells, primary patients' B-ALL samples expressing low antigen density in comparison to the NALM6 cell line were used (Figure 1B). CAR T cell anti-tumor potency was determined by assessing CAR T cell cytotoxicity and cytokine production. For in vivo therapeutic study, primary patients' B-ALL samples with dimly expressed CD19 and CD22 were used to evaluate and compare the therapeutic efficacy of mono- versus bi-specific CAR T cells. Additionally, we generated a LAD tumor model by deleting the highly expressed CD19 and CD22 from the ALL cell line NALM6 using CRISPR/Cas9, transducing the now antigen-negative cell line with CD19 and CD22, followed by single cell cloning to generate a cell line expressing low antigen density for both the CD19 and CD22. We engrafted tumor cells in NSG mice, followed by administration of CAR19, CAR22, CAR19/22 or untransduced T cells. Therapeutic efficacy was assessed by measuring tumor burden using either flow cytometry or bioluminescent imaging. RESULTS Cytotoxicity assay revealed that the bi-specific CAR19/22 T cells killed tumor cells more rapidly than CAR19 or CAR22 T cells. Further, compared to mono-specific CAR T cells, the bi-specific CAR19/22 T cells produced significantly more pro-inflammatory cytokines including IL-2 and IFNg, in response to stimulation with LAD primary samples or NALM6 cells. This increased cytokine-producing capacity compared to mono-specific CAR T cells was maintained following repeated antigen stimulation when in vitro exhaustion assay was performed. In vivo, enhanced tumor elimination was observed in mice receiving bi-specific CAR19/22 T cells compared to either of the mono-specific CAR T cells, in both low antigen density primary ALL and NALM6 tumor models. This translated to increased survival rates seen in mice treated with the bi-specific CAR19/22 T cells (Figure 1C-D). CONCLUSIONS Here we showed that bi-specific CAR19/22 T cells are superior to mono-specific CAR19 or CAR22 T cells, not only against LAD tumors but also tumor cells expressing high antigen density, NALM6. This was demonstrated by their enhanced cytokine-producing function, cytotoxic capacity, and therapeutic efficacy in vivo. Results from this study provide a novel rationale for repurposing multi-specific CAR T cells as a strategy to improve efficacy against LAD tumors, in addition to the recognized benefit of reducing antigen-negative escape. Figure 1 Figure 1. Disclosures Shestova: Hemogenyx Pharmaceuticals LLC: Research Funding. Grupp: Novartis, Roche, GSK, Humanigen, CBMG, Eureka, and Janssen/JnJ: Consultancy; Novartis, Kite, Vertex, and Servier: Research Funding; Novartis, Adaptimmune, TCR2, Cellectis, Juno, Vertex, Allogene and Cabaletta: Other: Study steering committees or scientific advisory boards; Jazz Pharmaceuticals: Consultancy, Other: Steering committee, Research Funding. Ruella: viTToria biotherapeutics: Research Funding; Novartis: Patents & Royalties; BMS, BAYER, GSK: Consultancy; AbClon: Consultancy, Research Funding; Tmunity: Patents & Royalties. Gill: Novartis: Other: licensed intellectual property, Research Funding; Interius Biotherapeutics: Current holder of stock options in a privately-held company, Research Funding; Carisma Therapeutics: Current holder of stock options in a privately-held company, Research Funding.

scholarly journals Ibrutinib before Apheresis May Improve Tisagenlecleucel Manufacturing in Relapsed/Refractory Adult Diffuse Large B-Cell Lymphoma: Initial Results from a Phase 1b Study

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 3-4
Author(s):  
Julio C. Chavez ◽  
Frederick L. Locke ◽  
Ellen Napier ◽  
Carl Simon ◽  
Andrew Lewandowski ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Biomedical Research ◽  
Research Funding ◽  
B Cell Lymphoma ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T

Background: Tisagenlecleucel (tisa-cel), an autologous anti-CD19 chimeric antigen receptor (CAR)-T cell therapy, has demonstrated durable responses and a manageable safety profile in adult patients (pts) with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL). It has previously been suggested that prior therapy with ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, may improve tisa-cel manufacturing, in vivo cellular kinetics, and antitumor efficacy (Fraietta et al. Blood. 2016). Moreover, since BTK signaling is involved in direct pro-inflammatory polarization of macrophages, as well as indirectly by T cells, it is hypothesized that ibrutinib may mitigate CAR-T cell-related toxicities such as cytokine release syndrome (CRS) and neurological events (NE). We report the initial results from a Phase Ib, multicenter, open-label trial evaluating the safety and tolerability of tisa-cel in combination with ibrutinib in adult pts with r/r DLBCL. Methods: Adult pts with r/r DLBCL who received &gt;2 prior lines of systemic therapy, including pts who progressed after or were ineligible for autologous stem cell transplant, were enrolled. The study design has 2 nonrandomized arms. In Arm 1, pts received ibrutinib 560 mg/d for ~4 weeks prior to leukapheresis; in Arm 2, pts were exposed to ibrutinib after leukapheresis. In both arms, ibrutinib was continued throughout lymphodepleting chemotherapy, tisa-cel infusion, and post infusion for up to 24 months. Lymphodepleting chemotherapy, ending at least 2 days before tisa-cel infusion, was either fludarabine (25 mg/m2) and cyclophosphamide (250 mg/m2) daily for 3 days or bendamustine (90 mg/m2) daily for 2 days. Pts received a single infusion of tisa-cel (target dose: 0.6-6.0×108 viable CAR+ T cells). Primary endpoints are incidence and severity of adverse events and ibrutinib dose interruptions/modifications. Secondary endpoints include best overall response (BOR) by Lugano criteria and cellular kinetics of tisa-cel. Results: As of June 9, 2020, 10 pts have been treated and observed through at least the Day 28 assessment: 4 in Arm 1 and 6 in Arm 2. Median age was 59 (range, 32-67) in Arm 1 and 64 (range, 58-76) in Arm 2. Median number of prior therapies was 3.5 (range, 2-5) in Arm 1 and 2 (range, 2-3) in Arm 2. Three of 10 pts (Arm 1, n=1; Arm 2, n=2) had an activated B-cell-like subtype of DLBCL. Six of 10 pts (Arm 1, n=1; Arm 2, n=5) had grade 1 CRS (by Lee scale) and 1 pt had NE (Arm 2, grade 1 by ASTCT criteria; Table). One pt in Arm 2 had grade 3 neutropenia lasting &gt;28 days post tisa-cel infusion. No other pts had grade 3 or 4 neutropenia or thrombocytopenia lasting &gt;28 days. No major bleeding events were observed. Ibrutinib-related bradycardia and atrial fibrillation (both grade 2) were each observed in 1 pt in Arm 1; supraventricular tachycardia (grade 1) related to tisa-cel was observed in 1 pt in Arm 2. No pt required tocilizumab or ICU admission. As of data cutoff, BOR in Arm 1 was complete response (CR) in 2 pts and partial response (PR) in 2 pts, with no relapses. BOR in Arm 2 was CR in 2 pts, PR in 1 pt, and progressive disease in 3 pts (Table). CAR-T cell expansion in vivo by qPCR was in line with data from the pivotal JULIET trial, except for 1 pt in Arm 2 whose transgene levels were below the limit of quantification at all points in time and who progressed at Day 28. Median viability of the leukapheresis material was 96.80% (range, 88.8-97.3) in Arm 1 and 90.95% (range, 88.1-94.7) in Arm 2. A naïve/stem cell-like central memory phenotype (CD45RA+/CCR7+) was observed in 24.05% (median; range, 15.9-37.0) of CD8+ T cells in the leukapheresis material for Arm 1 and in 8.12% (median; range, 1.3-20.4) for Arm 2 (Fig.1A). Fig.1B shows total CAR+ manufactured cells in each arm. The median dose of the final product was 3.9×108 CAR+ T cells in Arm 1 (range, 3.4-4.6×108 CAR+ T cells; median viability 92.25%) and 1.7×108 CAR+ T cells in Arm 2 (range, 1.2-3.0×108 CAR+ T cells; median viability 85.8%; Fig.1C). IFNγ secretion of tisa-cel in vitro in response to CD19+ target cells was similar between the 2 arms, whereas median normalized IL-2 responses were 23.1 fg/CAR+ cell in Arm 1 (range, 16.7-43.8) and 1.1 fg/CAR+ cell in Arm 2 (range, 0-17.3). Conclusions: These results support the feasibility of administering ibrutinib to pts with DLBCL throughout tisa-cel therapy. When given before apheresis, ibrutinib may improve CAR-T cell manufacturing, although further studies are needed to confirm this finding. Disclosures Chavez: AstraZeneca: Speakers Bureau; Morphosys: Consultancy, Speakers Bureau; Merck: Research Funding; Bayer: Consultancy; BeiGene: Speakers Bureau; Karyopharm: Consultancy; Genentech: Speakers Bureau; AbbVie: Consultancy; Epizyme: Speakers Bureau; Gilead: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Kite, a Gilead Company: Consultancy, Speakers Bureau; Verastem: Consultancy; Pfizer: Consultancy. Locke:Kite, a Gilead Company: Consultancy, Research Funding; Calibr: Consultancy; Celgene/Bristol-Myers Squibb: Consultancy; Novartis: Consultancy; GammaDelta Therapeutics: Consultancy; Cellular Biomedicine Group: Other: Consultancy with grant options; Allogene: Consultancy; Wugen: Consultancy. Simon:Novartis: Current Employment. Lewandowski:Novartis Institutes for BioMedical Research: Current Employment. Awasthi:Novartis Institutes for BioMedical Research: Current Employment. Engels:Novartis Institutes for BioMedical Research: Current Employment. Georgala:Novartis Pharmaceuticals Corporation: Current Employment. Bondanza:Novartis Institutes for BioMedical Research: Current Employment. Schuster:AlloGene, AstraZeneca, BeiGene, Genentech, Inc./ F. Hoffmann-La Roche, Juno/Celgene, Loxo Oncology, Nordic Nanovector, Novartis, Tessa Therapeutics: Consultancy, Honoraria; Novartis, Genentech, Inc./ F. Hoffmann-La Roche: Research Funding.

scholarly journals Endothelial Activation and Blood-Brain Barrier Disruption in Neurotoxicity after CD19 CAR-T Cell Immunotherapy

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 805-805
Author(s):  
Cameron J. Turtle ◽  
Kevin A. Hay ◽  
Laila-Aicha Hanafi ◽  
Juliane Gust ◽  
W. Conrad Liles ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Research Funding ◽  
Endothelial Activation ◽  
Advisory Board ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
High Concentrations

Abstract CD19 chimeric antigen receptor (CAR)-modified T cell therapy has produced impressive results in patients (pts) with CD19+B cell malignancies; however, treatment can be complicated by neurologic adverse events (AEs). The presentation and pathogenesis of neurotoxicity (NT) are incompletely understood. We report a clinical and pathologic study evaluating NT in 133 B-ALL, NHL and CLL pts treated with lymphodepletion chemotherapy and CD19 CAR-T cells (NCT01865617). Neurologic AEs were observed in 53 of 133 pts (40%; 19% grade [gr] 1-2; 16% gr 3; 2% gr 4; 3% gr 5). Most neurologic AEs were reversible. Delirium, headache, and language disturbances were the most frequently observed neurologic AEs, presenting in 66%, 55%, and 34% of pts with NT, respectively. Multivariable analysis showed that higher burden of malignant B cells in marrow, lymphodepletion with cyclophosphamide and fludarabine, and higher infused CAR-T cell dose were associated with increased risk of NT and cytokine release syndrome (CRS). The severity of NT correlated with higher peak concentrations of cytokines that may activate endothelial cells (EC), such as IL-6, IFN-γ, and TNF-α. Pts who developed gr ≥3 NT had more severe CRS with higher CAR-T cell counts in blood and evidence of vascular dysfunction. In severe NT, hypofibrinogenemia with elevated PT, aPTT, and d-dimer were consistent with EC activation. We confirmed in vivo EC activation during NT by demonstrating high concentrations of serum angiopoietin-2 (Ang-2) and von Willebrand Factor (VWF), which are released from Weibel-Palade bodies on EC activation. In vitro, serum from pts with NT induced activation and VWF release from human umbilical vein ECs (HUVECs), which suggests that the finding of a reduced fraction of high molecular weight VWF multimers in vivo during gr ≥4 NT results from consumption on platelets and sequestration on activated EC. Consistent with this explanation, we found reduced activity of the VWF-cleaving protease ADAMTS13 relative to VWF levels and more severe thrombocytopenia in pts with gr ≥4 NT. We considered that cytokine-induced EC activation might alter the integrity of the blood-brain barrier (BBB) during NT. During severe NT, CSF analyses demonstrated increased permeability of the BBB to protein and leukocytes, including CAR-T cells. The gradient between serum and CSF cytokines observed before lymphodepletion was lost during acute NT, consistent with inability of the BBB to shield the CNS from high concentrations of plasma cytokines. Brain vascular pericytes (BVP) play a critical role in vascular and BBB support, and when exposed to high TNF-α or IFN-γ concentrations BVP exhibited stress (increased cleaved caspase-3 and reduced PDGFRβ) and secreted IL-6 and VEGF, further promoting EC activation and BBB permeability. Neuropathologic examination of the brain of a patient with fatal NT demonstrated disrupted endothelium by CD31 immunohistochemistry and EC activation was confirmed by intravascular VWF binding and CD61+ platelet microthrombi. Further evidence of breach of the BBB included red blood cell extravasation from multiple vessels, vascular lesions with karyorrhexis, perivascular CD8+ T cell infiltration, and fibrinoid vessel wall necrosis. CAR-T cells were detected in the CNS. We investigated strategies to reduce the risks of severe NT. Logistic probability curves demonstrated that reduction in CAR-T cell dose to reduce the peak in vivo CAR-T cell blood count was associated with reduced risk of NT, but that the narrow therapeutic index of this approach would lead to loss of anti-tumor efficacy. To maintain CAR-T cell peak counts in blood, we developed a strategy to identify pts early after CAR-T cell infusion who might be at risk of subsequent severe NT and could be candidates for early intervention. Classification tree modeling demonstrated that in the first 36 hours after CAR-T cell infusion pts with fever ≥38.9°C, serum IL-6 ≥16 pg/mL, and MCP-1 ≥1343.5 pg/mL were at high risk of subsequent gr ≥4 NT (sensitivity 100%; specificity 94%). We also investigated whether pts with pre-existing endothelial activation were at higher risk of NT. Before lymphodepletion, pts who developed gr ≥4 NT had higher Ang-2:Ang-1 ratios than those with gr ≤3 NT, indicating that endothelial activation before lymphodepletion or CAR-T cell infusion may be a risk factor for NT that identifies pts who would benefit from a modified treatment regimen. Disclosures Turtle: Adaptive Biotechnologies: Other: Advisory board; Bluebird Bio: Other: Advisory board; Gilead Sciences: Other: Advisory board; Precision Biosciences: Other: Advisory board; Celgene: Other: Advisory board; Juno Therapeutics: Other: Advisory board, Patents & Royalties, Research Funding. Liles: Juno Therapeutics: Consultancy, Other: Advisory board. Li: Juno Therapeutics: Employment, Equity Ownership. Yeung: Gilead: Research Funding. Riddell: Juno Therapeutics: Equity Ownership, Patents & Royalties, Research Funding. Maloney: Celgene: Other: Advisory board; Kite Pharmaceuticals: Other: Advisory board; Juno Theraapeutics: Other: Advisory board, Patents & Royalties, Research Funding; Roche/Genetech: Other: Advisory board.

scholarly journals Optimal Dual-Targeted CAR Construct Simultaneously Targeting Bcma and GPRC5D Prevents Bcma-Escape Driven Relapse in Multiple Myeloma

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 136-136 ◽  
Author(s):  
Carlos Fernandez de Larrea ◽  
Mette Staehr ◽  
Andrea Lopez ◽  
Yunxin Chen ◽  
Terence J Purdon ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Research Funding ◽  
Car T Cells ◽  
Car T Cell ◽  
Dual Targeting ◽  
Car T ◽  
Previously Treated

Multiple myeloma (MM) remains generally incurable, calling for the development of novel treatment strategies such as chimeric antigen receptor (CAR) T cell therapy. Most clinically tested CAR T cell therapies for MM target B cell maturation antigen (BCMA), but despite high response rates, many patients relapse (Raje N. NEJM 2019). BCMA negative-low MM cells are implicated as a reservoir preceding relapse (Brudno J. JCO 2018; Cohen A. JCI 2019). Our aims are to (1) evaluate whether upfront simultaneous targeting of an additional antigen such as G protein-coupled receptor class C group 5 member D (GPRC5D; Smith EL. Sci Trans Med 2019) can mitigate BCMA escape-mediated relapse in MM, and (2) compare dual targeting strategies to identify an optimal approach. Dual targeting for CD19/CD22 malignancies has been investigated, and multiple approaches are feasible; however, approaches have yet to be comprehensively compared head to head. Here, we compare 2 parallel production and 3 single-vector dual targeting strategies (Fig. 1A). To enhance clinical translatability, all strategies are built on the BCMA(125)/4-1BBζ CAR (BCMA scFv 125; Smith EL. Mol Ther 2018), which is currently under multi-center clinical investigation (NCT03430011; Mailankody S. ASH 2018). We confirmed that all dual targeted approaches lyse, proliferate, and secrete polyfunctional cytokines specifically in response to BCMA and GPRC5D mono- and dual-positive cell lines and/or primary patient MM aspirate samples. Activity in vivo was confirmed using the bone marrow-tropic OPM2 MM model (endogenously BCMA+GPRC5D+). In all experiments MM cells (2 x 106) were injected IV into NSG mice and engrafted/expanded for 14 days before treatment. A high dose of all dual targeted CAR T cell approaches (3 x 106 CAR+) induced long-term disease control (median overall survival (mOS) BCMA(125) non-signaling del control 32d vs other groups mOS not reached; p &lt; 0.05). Prevention of latent BCMA escape-mediated relapse was evaluated by re-challenge of previously treated long-surviving mice with 2 x 106 OPM2 BCMA CRISPR KO (OPM2BCMA KO) cells at day 100 without re-treatment. While mice previously treated with BCMA(125)/41BBζ CAR T cells succumbed to OPM2BCMA KO disease, dual targeted approaches prevented OPM2BCMA KO growth (mOS BCMA mono-targeted arm 37d post re-challenge vs other groups mOS not reached; p &lt; 0.05). To better recapitulate human MM and distinguish among dual targeting approaches, we modeled established BCMA heterogeneous disease by spiking 5-10% OPM2BCMA KO into bulk OPM2WT cells for injection. Each OPM2 population was modified to express distinct luciferases for simultaneous in vivo monitoring by bioluminescent imaging (BLI). Treatment with a moderate (5 x 105) dose of CAR T cells eradicated OPM2WT cells in all groups, but anti-GPRC5D CARs with CD28 co-stimulation, whether included within a mixed T cell population or in a bicistronic construct (Fig. 1A ii, iv), failed to control OPM2BCMA KO cells (Fig. 1B). Correspondingly, 4-1BB-only containing CAR T cells had increased in vivo expansion (2.1-4.1-fold increase CAR T cell BLI at day 7 over CD28 containing groups; p &lt; 0.05). As this result is likely from greater activation-induced cell death in the CD28-containing approaches that was not rescued by 4-1BB, we later compared 4-1BB-only containing approaches (Fig. 1A i, iii, v). These 3 dual targeting approaches effectively controlled OPM2WT disease at moderate (1 x 106 CAR+) and low (2.5 x 105 CAR+) doses. However, when using a sub-therapeutic dose (2.5 x 105 CAR+) in the OPM2BCMA KO-spiked model, the tandem scFv-single stalk design was least effective in controlling OPM2BCMA KO disease (Fig 1C). At a dose that is sub-therapeutic to control OPM2WT disease (1 x 105 CAR+), the bicistronic dual 4-1BB design (Fig. 1A iii) was more effective in eradicating tumor compared with the parallel production approach (6-fold difference tumor BLI at day 28; p &lt; 0.05). These results indicate that upfront dual targeting of BCMA/GPRC5D with CAR T cells can mitigate BCMA escape-mediated relapse in a model of MM. While parallel infusion of separate BCMA- and GPRC5D-targeted CAR T cells is effective, a single bicistronic vector encoding two 4-1BB-containing CARs avoids the practical challenges of parallel manufacturing, and uniquely may provide superior anti-MM efficacy. Figure Disclosures Fernandez de Larrea: Takeda: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding. Brentjens:JUNO Therapeutics: Consultancy, Patents & Royalties, Research Funding; Celgene: Consultancy. Smith:Celgene: Consultancy, Patents & Royalties, Research Funding; Fate Therapeutics and Precision Biosciences: Consultancy.

scholarly journals 136 ATA3271: An armored, next-generation off-the-shelf, allogeneic, mesothelin-CAR T cell therapy for solid tumors

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A145-A145
Author(s):  
Xianhui Chen ◽  
Jiangyue Liu ◽  
Shuai Yang ◽  
Amogh Oke ◽  
Sarah Davies ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Next Generation ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T Cell Therapy ◽  
Car T

BackgroundMesothelin (MSLN) is a GPI-anchored membrane protein with high expression levels in an array of malignancies including mesothelioma and is an attractive target antigen for tumor surface antigen-targeting therapies. Regional administration of autologous, 2nd generation MSLN-targeted CAR-T cells for malignant pleural mesothelioma has shown promise in early clinical evaluation.1 2 More recently, a next-generation MSLN-targeted, autologous CAR T therapy leveraging 1XX CAR signaling and PD1DNR is currently under investigation for advanced mesothelioma [NCT04577326]. Although autologous MSLN CAR-T holds promise, an allogeneic approach may have more widespread application. EBV T-cells represent a unique, non-gene edited approach for allogeneic T-cell therapy. EBV-specific T-cells are currently in a phase 3 trial for EBV-positive post-transplant lymphoproliferative disease [NCT03394365] and, to-date, have demonstrated a favorable safety profile with no evidence for GvHD and cytokine release syndrome attributable to EBV T-cells. Clinical proof-of-principle studies for CAR transduced CD19-targeted allogeneic EBV T-cell therapies have shown acceptable safety and durable response.3 The first preclinical evaluation of ATA3271 was reported last year.4 Here, we describe updated preclinical data for this potential off-the-shelf, allogeneic cell therapy.MethodsWe engineered MSLN CAR+ EBV T-cells (ATA3271) with a novel 1XX signaling domain that is associated with strong effector function and favorable persistence, as well as armored with PD1DNR to provide intrinsic checkpoint blockade.5 Anti-tumor effect of ATA3271 was assessed using a MSTO-211H-derived tumor cell line overexpressing MSLN and PDL1.ResultsUpon MSLN engagement, ATA3271 showed proliferation, efficient tumor cell lysis in the presence of high-level cell-surface PD-L1 expression and secretion of effector cytokines [IL-2, TNF-α, granzyme B]. In a 16-day serial stimulation assay, with PD-L1+ tumor cells added every 2–3 days, ATA3271 expanded 4 to 45-fold without the need for external cytokines, and retained comparable antitumor function as CD3/CD28-stimulated ‘autologous’ CAR-T cells. In an orthotopic mouse model of pleural mesothelioma, ATA3271 demonstrated anti-tumor efficacy without toxicities. Memory markers [CD62L, CCR7] play a key role for T-cell persistence in vivo. We identified donor-to-donor variability in memory marker expression on ATA3271 and optimized our process to maximize their expression. Memory marker expression impact on ATA3271 potency, both in vitro and in vivo, will be presented.ConclusionsOverall, these in vitro and in vivo data show potent anti-tumor activity without evidence of toxicity, suggesting that ATA3271 may be a promising approach for the treatment of MSLN-positive cancers that warrants further clinical investigation.ReferencesAdusumilli Prasad S, et al. Abstract CT036: A phase I clinical trial of malignant pleural disease treated with regionally delivered autologous mesothelin-targeted CAR T cells: Safety and efficacy. Cancer Res 2019;79(13 Suppl):Abstract CT036.Adusumilli Prasad S, et al. A phase I trial of regional mesothelin-targeted CAR T-cell therapy in patients with malignant pleural disease, in combination with the anti-PD-1 agent pembrolizumab. Cancer Discov 2021.Curran Kevin J, et al. Durable remission following ‘off-the-shelf’ chimeric antigen receptor (CAR) T-cells in patients with relapse/refractory (R/R) B-cell malignancies. Biol Blood Marrow Transplant 2020;26.3: S89.Liu Jiangyue, et al. 98 ATA3271: an armored, next-generation off-the-shelf, allogeneic, mesothelin-CAR T cell therapy for solid tumors. JITC 2020;8.Feucht Judith, et al. Calibration of CAR activation potential directs alternative T cell fates and therapeutic potency. Nat Med 2019;25.1: 82–88.

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