CD19-targeted Chimeric Antigen Receptor Research Articles

Oncotherapy resistance explained by Darwinian and Lamarckian models.

Cell and antibody therapies directed against surface molecules on B cells, e.g., CD19-targeting chimeric antigen receptor T cells (CD19 CAR-T), are now standard for patients with chemorefractory B cell acute lymphoblastic leukemias and other B cell malignancies. However, early relapse rates remain high. In this issue of the JCI, Aminov, Giricz, and colleagues revealed that leukemia cells resisting CD19-targeted therapy had reduced CD19 but also low CD22 expression and were sensitive to Bruton's tyrosine kinase and/or MEK inhibition. Overall, their observations support the evolution of resistance following a Lamarckian model: the oncotherapy directly elicits adaptive, resistance-conferring reconfigurations, which are then inherited by daughter cells as epigenetic changes. The findings prompt reflection also on the broader role of epigenetics in decoupling of replication from lineage differentiation activation by the B cell lineage master transcription factor hub. Such oncogenesis and resistance mechanisms, being predictable and epigenetic, offer practical opportunities for intervention, potentially non-cross-resistant and safe vis-à-vis present cytotoxic and CAR-T treatments.

IL-18-secreting multi-antigen targeting CAR T-cells eliminate antigen-low myeloma in an immunocompetent mouse model

Multiple myeloma is a plasma cell malignancy that is currently incurable with conventional therapies. Following the success of CD19-targeted chimeric antigen receptor (CAR) T-cells in leukemia and lymphoma, CAR T-cells targeting B-cell maturation antigen (BCMA) more recently demonstrated impressive activity in relapsed and refractory myeloma patients. However, BCMA-directed therapy can fail due to low expression of BCMA on myeloma cells, suggesting that novel approaches to better address antigen-low disease may improve patient outcomes. We hypothesized that engineered secretion of the pro-inflammatory cytokine interleukin-18 (IL-18) and multi-antigen targeting could improve CAR T-cell activity against BCMA-low myeloma. In a syngeneic murine model of myeloma, CAR T-cells targeting the myeloma-associated antigens BCMA and B-cell activating factor (BAFF-R) failed to eliminate myeloma when these antigens were weakly expressed, whereas IL-18-secreting CAR T-cells targeting these antigens promoted myeloma clearance. IL-18-secreting CAR T-cells developed an effector-like T-cell phenotype, promoted interferon-gamma production, reprogrammed the myeloma bone marrow microenvironment through type I/II interferon signaling, and activated macrophages to mediate anti-myeloma activity. Simultaneous targeting of weakly expressed BCMA and BAFF-R with dual-CAR T-cells enhanced T-cell:target cell avidity, increased overall CAR signal strength, and stimulated anti-myeloma activity. Dual-antigen targeting augmented CAR T-cell secretion of engineered IL-18 and facilitated elimination of larger myeloma burdens in vivo. Our results demonstrate that combination of engineered IL-18 secretion and multi-antigen targeting can eliminate myeloma with weak antigen expression through distinct mechanisms.

Abstract CT129: A phase 1 dose escalation study of a novel coupled CAR T cell therapy, GCC19CART, for patients with metastatic colorectal cancer

Abstract Background: GCC19CART, the first clinical candidate from the CoupledCAR solid tumor platform, is designed to overcome the limitations of conventional CAR T-cells in solid tumor malignancies by pairing solid tumor CAR T-cells with CD19-targeting CAR T-cells to amplify the proliferation and activation of the solid tumor CAR T component. GCC19CART targets guanylate cyclase-C (GCC), which is reported to be expressed in the metastatic lesions of 70%-80% of subjects with colorectal cancers and largely restricted to the intestinal tract. A Phase 1 investigator-initiated clinical trial conducted in China showed preliminary efficacy with an overall response rate (ORR) at dose level 1 (1x106 CAR T-cells/kg) of 15.4% ORR (2/13) and 50% ORR (4/8) in dose level 2 (2x106 CAR T-cells/kg). Common side effects included cytokine release syndrome (CRS) and diarrhea/colitis. Immune effector cell-associated neurotoxicity syndrome (ICANS) was seen in a smaller proportion of patients. A phase 1 study was initiated in the United States in August 2022 for patients with metastatic colorectal cancer refractory to standard of care chemotherapy. As of a data cutoff on ​November 1, 2023, 4 subjects have been treated in the initial dose level. Methods: Subjects were initially screened for GCC expression; this requirement was later discontinued when immunohistochemistry studies revealed that the frequency of positive GCC expression exceeded 95%. Eligible subjects underwent leukapheresis, a single dose of lymphodepleting chemotherapy (fludarabine 30mg/m2 and cyclophosphamide 300mg/m2) 3 days prior to infusion, and then administration of a single infusion of GCC19CART. Responses were assessed by RECIST v1.1 by site investigator review and an independent third-party imaging contract research organization. Results: 4 subjects have been dosed at level 1 (1x106 cells/kg) and completed the DLT period at the time of data cutoff. The most common adverse events were CRS in 4/4 subjects (Grade 1: 2/4 (50%) or Grade 2: 2/4 (50%)) and diarrhea in 3/4 subjects (Grade 1: 1/4 (25%), Grade 2: 1/4 (25%), or Grade 3: 1/4 (25%)). Three out of four patients had a mild tremor (Grade 1) that resolved with corticosteroids and no other evidence of neurotoxicity. The combined overall response rate (ORR) was 50% (2/4) by independent review. Two subjects demonstrated a partial response (PR) while 1 additional subject had partial metabolic response (PMR) on PET/CT with stable disease (SD) and 1 patient had progressive disease per RECIST 1.1. Per site investigator review, the ORR was 25%, with 1 confirmed PR and 3 SD assessed as best response. The median PFS was 3.8 months in the dose level 1 group. Conclusions: Preliminary results demonstrate that GCC19CART has meaningful clinical activity and an acceptable safety profile in refractory metastatic colorectal cancer. This trial is ongoing and updated data will be presented, including from patients treated at dose level 2 (2x106 CAR T-cells/kg). Clinical trial information: NCT05319314. Citation Format: Bridget P. Keenan, Christopher H. Lieu, Marwan Fakih, Dongqi Chen, Lucy Lu, Eric Rowinsky, Victor Lu, Lei Xiao, Alan P. Venook, Benjamin Schlechter. A phase 1 dose escalation study of a novel coupled CAR T cell therapy, GCC19CART, for patients with metastatic colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT129.

Regulatory T cells expressing CD19-targeted chimeric antigen receptor restore homeostasis in Systemic Lupus Erythematosus

Systemic Lupus Erythematosus (SLE) is a progressive disease leading to immune-mediated tissue damage, associated with an alteration of lymphoid organs. Therapeutic strategies involving regulatory T (Treg) lymphocytes, which physiologically quench autoimmunity and support long-term immune tolerance, are considered, as conventional treatment often fails. We describe here a therapeutic strategy based on Tregs overexpressing FoxP3 and harboring anti-CD19 CAR (Fox19CAR-Tregs). Fox19CAR-Tregs efficiently suppress proliferation and activity of B cells in vitro, which are relevant for SLE pathogenesis. In an humanized mouse model of SLE, a single infusion of Fox19CAR-Tregs restricts autoantibody generation, delay lymphopenia (a key feature of SLE) and restore the human immune system composition in lymphoid organs, without detectable toxicity. Although a short survival, SLE target organs appear to be protected. In summary, Fox19CAR-Tregs can break the vicious cycle leading to autoimmunity and persistent tissue damage, representing an efficacious and safe strategy allowing restoration of homeostasis in SLE.

Abstract 47: Stabilization of long CAR T cells is crucial for in vivo antitumor efficacy

Abstract Introduction: Genetically engineered T cells expressing chimeric antigen receptors (CARs) have shown substantial anti-tumor efficacy in hematological malignancies during recent years. As the field evolves to novel target epitopes, longer CAR structures are needed to reach membrane proximal epitopes for improved efficacy. Our approach to reach such epitopes is to have (non-functional) SIRPalpha based extracellular extension, spacer, to our CAR structure. We have shown, in this proof-of-concept study, that stability of the extracellular spacer of a CAR plays a pivotal role to improve in vivo anti-tumor efficacy. Various SIRPalpha-based CARs, FiCARs, targeting CD19 was studied for their function. Protein stability of the CD19 CAR structures were characterized and subsequently the killing efficacy of target cells and cytokine release in in vitro as well as in vivo anti-tumor efficacy was evaluated. Methods & Results: In vitro co-culture assays with primary CD19 CAR T and CD19 positive cancer cells had shown no significant differences between the different spacer containing FiCAR structures. A dose dependent killing efficacy was observed in all the tested structures with up to >90% killing of NALM6 and Raji cells. Comparable results for IL-2, IFN-gamma, TNF-alpha, IL-4, IL-13 and granzyme B response were seen in co-cultured assay. In the protein stability studies, modifications in the extracellular part of the CAR structure led to an increase in thermal stability (over 2 °C) and reduced/halted multimer formation. To study the FiCAR T cell function in an in vivo tumor model, NSG mice were injected i.v with Raji cells and few days later mice were injected i.v with FiCAR T cells. Anti-tumor efficacy and overall survival were studied at the end of the study (60 days), the enhanced stability of FiCAR T structure translated into improved anti-tumor efficacy and survival. Interestingly, none of the mice survived in the least stable structure, 40% survival with intermediate stability structures and over 70% survival was observed in most stable structures. Conclusion: A stabilized SIRPalpha-based CD19 FiCARs dramatically enhance anti-tumor efficacy and survival in Raji tumor model. The stabilization is critical for improved efficacy, especially in the in vivo setting. This data suggests that, in addition to the length of the CARs stability of the CAR structure appear to play a crucial role in the efficacy of the CAR T cells. The modifications presented here enhanced CD19-targeting CAR T cell efficacy. This approach requires further investigation to improve the efficacy of currently approved CAR T cells, especially CD19-CAR T cells. Citation Format: Henrik Paavilainen, Jan Koski, Veera Nikoskelainen, Manar Elmadani, Endrit Elbasani, Can Hekim, Emmi-Leena Ihantola, Virginie Kergourlay, Pirjo Vehmaan-kreula, Marie Nyman, Kiira Kalke, Markus Nurmi, Hector Monzo, Paivi Ojala, Anu Autio, Matti Korhonen, Anil Thotakura. Stabilization of long CAR T cells is crucial for in vivo antitumor efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 47.

Abstract 1335: Generating functional CAR-NK cells for cancer immunotherapy

Abstract Chimeric Antigen Receptor-Natural Killer (CAR-NK) cells are rapidly emerging as a promising cellular therapeutic overcoming the potential life-threatening adverse events that may result from CAR-T therapy, including cytokine release syndrome (CRS), neurotoxicity and graft-versus-host disease (GVHD). Due to their intrinsic characteristics, NK cells can kill tumor cells without the requirement for recognition of antigen in the context of MHC. This removes the constraint of HLA matching and supports antigen independent cytotoxicity through NK cell intrinsic mechanisms. As such CAR-NK cells kill via both CAR-dependent and -independent mechanisms. For these reasons, they offer the advantage of being an “off-the-shelf” product; satisfying the requirement for large-scale production of cancer immunotherapies, with the potential to reach more patients at a reduced cost. The frequency of NK cells in the blood is low (~ 2-5%), therefore improving their in vitro expansion is key to generating sufficient material to offer a viable CAR-NK cell therapy. Here we outline an in-vitro method to generate, expand, and test primary human CAR-NK cells using engineered feeder cells, and go on to demonstrate the efficacy of the CAR-NK against target cancer cells. Primary human NK cells were cultured and expanded in the presence of irradiated K562 cells (iK562) modified to express 4-1BBL and membrane bound IL-21. Following initial expansion, NK cells were transduced with a clinically tested CD19-targeting CAR lentiviral vector (LV) or GFP expressing LV; as an empty vector transduced control. Following transduction, CD19 CAR-NK and GFP-NK were enriched by FACS sorting to reach >80% purity and further expanded in the presence of 4-1BBL/mbIL21 iK562 feeder cells. Following sufficient expansion, cytotoxicity of fresh or cryopreserved CD19 CAR-NK cells was tested in vitro in a Tumor Killing Assay (TKA) against CD19+ or CD19- target cells. As expected, CD19 CAR-NK cells showed increased on-target cytotoxicity, increased degranulation and IFNꝩ secretion compared to controls. This effect was not observed with CD19 negative cancer cells, strongly suggesting CD19 CAR engagement of the target antigen to mediate killing. Taken together these data show the generation, expansion, and enrichment of CD19 CAR-NK cells with enhanced cytotoxic activity towards CD19+ target cells. This approach provides a platform for in vitro characterization of novel CAR-constructs, allied with in-vitro safety assessment and in vivo pharmacology testing. Together, this offers the potential to further develop new and more widely available cellular therapeutics to treat cancer. Citation Format: Karina Di Gregoli, Henry Leonard, Dan Rocca, Sabrina de Munnik, Gemma Moiset, Robert Nunan, Lauren Schewitz-Bowers, Louise Brackenbury. Generating functional CAR-NK cells for cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1335.

Abstract 3610: Utilizing fructose metabolism to fuel anti-tumor immunity

Abstract Consumption of fructose in the form of high fructose corn syrup is elevated in the western diet, but it is not fully understood how fructose metabolism influences anti-tumor immunity. Fructose is canonically metabolized in the intestine and the liver and can shunt into glycolysis. In certain tumor types, fructose metabolism becomes deregulated, allowing tumor cells to metabolize fructose to power their biosynthetic processes. Similarly, reprogramming immune cells to be able to efficiently metabolize fructose may help us power immunotherapy to work in difficult to treat cancers, especially in individuals who have high fructose in their blood or in the tumor microenvironment (TME). Imparting effector T cells with the ability to use fructose for fuel can overcome one of the major metabolic limitations of the TME: limited nutrient supply. As T cells become activated, they alter their metabolism to support growth and proliferation. Activated CD8+ T cells upregulate their glycolysis which results in increased biosynthetic processes, such as synthesis of macromolecules and effector cytokines. However, tumor cells also consume substantial amounts of glucose, resulting in a glucose-depleted microenvironment, which could be one of the major barriers to immunotherapy working in solid tumors. Therefore, we engineered T cells to overexpress a fructose transporter, GLUT5, which is normally not expressed in the immune compartment at high levels. We hypothesized that increased fructose uptake by CD8+ T cells will ameliorate exhaustion caused by the glucose-low tumor microenvironment. Indeed, we determined that GLUT5 T cells are more efficient in killing in low glucose supplemented with fructose. We also observed that GLUT5 expression restores T cell glycolytic capacity under fructose to that of unexhausted T cells under glucose replete conditions. Similarly, GLUT5-expressing T cells proliferate faster in vitro and exhibit an improved ability to control B16 tumor growth in vivo. Additionally, combining GLUT5 cell infusion with checkpoint inhibition resulted in durable tumor control and prolonged mouse survival. Further, engineered CD19-targeted CAR T cells with expression of GLUT5 were more metabolically active and cytotoxic in low glucose conditions, mimicking the TME. In conclusion, GLUT5 expression in effector CD8+ and CAR T cells may allow immunotherapy to function in solid tumors under low glucose conditions. Citation Format: Tanya Schild, Rachel Chirayil, Lyric Haughton, Patrick Wallisch, Marjan Berishaj, David A. Scheinberg, Kayvan R. Keshari. Utilizing fructose metabolism to fuel anti-tumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3610.

CD19-targeted chimeric antigen receptor T cell therapy in two patients with multiple sclerosis.

Progressive multiple sclerosis (MS) is characterized by compartmentalized smoldering neuroinflammation caused by the proliferation of immune cells residing in the central nervous system (CNS),including B cells. Although inflammatory activity can be prevented by immunomodulatory therapies during early disease, such therapies typically fail to halt disease progression. CD19 chimeric antigen receptor (CAR)-T cell therapies have revolutionized the field of hematologic malignancies. Although generally considered efficacious, serious adverse events associated with CAR-T cell therapies such as immune effector cell-associated neurotoxicity syndrome (ICANS) have been observed. Successful use of CD19 CAR-T cells in rheumatic diseases like systemic lupus erythematosus and neuroimmunological diseases like myasthenia gravis have recently been observed, suggesting possible application in other autoimmune diseases. Here, we report the first individual treatment with a fully human CD19 CAR-T cell therapy (KYV-101) in two patients with progressive MS. CD19 CAR-T cell administration resulted in acceptable safety profiles for both patients. No ICANS was observed despite detection ofCD19 CAR-T cells in the cerebrospinal fluid. In case 1, intrathecal antibody production in the cerebrospinal fluid decreased notably after CAR-T cell infusion and was sustained through day 64. CD19 CAR-T cell administration in progressive MS resulted in an acceptable safety profile. CAR-T cell presence and expansion were observed in the cerebrospinal fluid without clinical signs of neurotoxicity, which, along with intrathecal antibody reduction, indicates expansion-dependent effects of CAR-T cells on CD19+ target cells in the CNS. Larger clinical studies assessing CD19 CAR-T cells in MS are warranted. Both individual treatments as well the generated data were not based on external funding.

Dynamic monitoring of circulating tumor DNA reveals outcomes and genomic alterations in patients with relapsed or refractory large B-cell lymphoma undergoing CAR T-cell therapy

BackgroundOver 50% of patients with relapsed or refractory large B-cell lymphoma (r/r LBCL) receiving CD19-targeted chimeric antigen receptor (CAR19) T-cell therapy fail to achieve durable remission. Early identification of relapse...

Transient acute kidney injury after chimeric antigen receptor T-cell therapy in patients with hematological malignancies.

Acute kidney injury (AKI) occurs in 30% of patients infused with chimeric antigen receptor (CAR) T-cells. The purpose of this study was to identify risk factors and long-term outcomes after AKI in patients who received CAR T-cell therapy. Medical records of 115 adult patients with R/R hematological malignancies treated with CD19-targeted CAR T-cells at Vall d'Hebron University Hospital between July 2018 and May 2021. Baseline demographic data including age, gender, ethnicity, body mass index (BMI), and co-morbidities, as well as the type of hematological neoplasia and prior lines of therapy were collected. Laboratory parameters including serum creatinine and whole blood hemoglobin were retrospectively reviewed and values were gathered for days +1, +7, +14, +21, and +28 post-infusion. A total of 24/115 (21%) patients developed AKI related to CAR T-cell therapy; 6/24 with AKI over chronic kidney disease (CKD). Two patients had AKI in the context of lymphodepleting (LD) chemotherapy and the other 22 after CAR T-cell infusion, starting at day+1 in 3 patients, day+7 in 13 patients, day +14 in 1 patient, day+21 in 2 patients, and day+28 in 3 patients. Renal function was recovered in 19/24 (79%) patients within the first month after infusion. Male gender, CKD, cytokine release syndrome (CRS), and immune effector cell-associated neurotoxicity syndrome (ICANS) were associated with AKI. Male gender, CKD, ICANS grade ≥3 and CRS grade ≥2 were identified as independent risk factors for AKI on multivariable analysis. In terms of the most frequent CAR T-cell related complications, CRS was observed in 95 (82%) patients and ICANS in 33 (29%) patients. Steroids were required in 34 (30%) patients and tocilizumab in 37 (32%) patients. Six (5%) patients were admitted to the intensive care unit (1 for septic shock, 4 for CRS grade ≥2 associated to ICANS grade ≥2, and 1 for CRS grade ≥3). A total of 5 (4.4%) patients died in the first 30 days after CAR T-cell infusion for reasons other than disease progression, including 4 cases of infectious complications and 1 of heart failure. Our results suggest that AKI is a frequent but mild adverse event, with fast recovery in most patients.

Treatment of secondary CNS lymphoma using CD19-targeted chimeric antigen receptor (CAR) T cells

BackgroundAggressive B cell lymphoma with secondary central nervous system (CNS) involvement (SCNSL) carries a dismal prognosis. Chimeric antigen receptor (CAR) T cells (CAR-T) targeting CD19 have revolutionized the treatment for B cell lymphomas; however, only single cases with CNS manifestations successfully treated with CD19 CAR-T have been reported.MethodsWe prospectively enrolled 4 patients with SCNSL into our study to assess clinical responses and monitor T cell immunity.ResultsTwo of four SNCSL patients responded to the CD19-targeted CAR-T. Only one patient showed a substantial expansion of peripheral (PB) CAR-T cells with an almost 100-fold increase within the first week after CAR-T. The same patient also showed marked neurotoxicity and progression of the SNCSL despite continuous surface expression of CD19 on the lymphoma cells and an accumulation of CD4+ central memory-type CAR-T cells in the CNS. Our studies indicate that the local production of chemokine IP-10, possibly through its receptor CXCR3 expressed on our patient’s CAR-T, could potentially have mediated the local accumulation of functionally suboptimal anti-tumor T cells.ConclusionsOur results demonstrate expansion and homing of CAR-T cells into the CNS in SNCSL patients. Local production of chemokines such as IP-10 may support CNS infiltration by CAR-T cells but also carry the potential of amplifying local toxicity. Future studies investigating numbers, phenotype, and function of CAR-T in the different body compartments of SNSCL patients receiving CAR-T will help to improve local delivery of “fit” and highly tumor-reactive CAR-T with low off-target reactivity into the CNS.

Immunometabolic Adaptation of CD19-Targeted CAR T Cells in the Central Nervous System Microenvironment of Patients Promotes Memory Development.

The spatiotemporal immunometabolic landscape of CD19-targeted CAR T cells from patients reveals metabolic adaptations in specific microenvironments that can be exploited to maximize the therapeutic efficacy of CAR T cells.

Streamlined measurement of chimeric antigen receptor T-cell concentration, size, viability and two-color phenotyping during manufacturing

Background aimsThe successful development of CD19-targeted chimeric antigen receptor (CAR) T-cell therapies has led to an exponential increase in the number of patients recieving treatment and the advancement of novel CAR T products. Therefore, there is a strong need to develop streamlined platforms that allow rapid, cost-effective, and accurate measurement of the key characteristics of CAR T cells during manufacturing (i.e., cell number, cell size, viability, and basic phenotype). MethodsIn this study, we compared the novel benchtop cell analyzer Moxi GO II (ORFLO Technologies), which enables simultaneous evaluation of all the aforementioned parameters, with current gold standards in the field: the Multisizer Coulter Counter (cell counter) and the BD LSRFortessa (flow cytometer). ResultsOur results demonstrated that the Moxi GO II can accurately measure cell number and cell size (i.e., cell volume) while simultaneously assessing simple two-color flow cytometry parameters, such as CAR T-cell viability and CD4 or CAR expression. ConclusionsThese measurements are comparable with those of gold standard instruments, demonstrating that the Moxi GO II is a promising platform for quickly monitoring CAR T-cell growth and phenotype in research-grade and clinical samples.

Low-Dose Targeted Radioimmunotherapy (Iomab-ACT) Achieves Lymphocyte and Monocyte Depletion Prior to CD19-Targeted CAR T-Cell Therapy for Relapsed of Refractory B-Cell ALL or DLBCL with Minimal CRS and Icans

Low-Dose Targeted Radioimmunotherapy (Iomab-ACT) Achieves Lymphocyte and Monocyte Depletion Prior to CD19-Targeted CAR T-Cell Therapy for Relapsed of Refractory B-Cell ALL or DLBCL with Minimal CRS and Icans

T-Cell Large Granular Lymphocyte Population Involving Chimeric Antigen Receptor-Modified T (CAR T) Cells in Patients with Cytopenia after CD19-Targeted CAR T-Cell Therapy: Case Series

T-Cell Large Granular Lymphocyte Population Involving Chimeric Antigen Receptor-Modified T (CAR T) Cells in Patients with Cytopenia after CD19-Targeted CAR T-Cell Therapy: Case Series

CD19-targeting CAR T cells protect from ANCA-induced acute kidney injury

ObjectivesAnti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides (AAV) are life-threatening systemic autoimmune diseases manifesting in the kidneys as necrotizing crescentic glomerulonephritis (NCGN). ANCA antigens are myeloperoxidase (MPO) or proteinase 3. Current treatments...

Low-Frequency PPM1D Gene Mutations Affect Treatment Response to CD19-Targeted CAR T-Cell Therapy in Large B-Cell Lymphoma.

Chimeric antigen receptor T (CAR T)-cell therapy has become a standard treatment option for patients with relapsed or refractory diffuse large B-cell lymphoma (r/r DLBCL). Mutations in the PPM1D gene, a frequent driver alteration in clonal hematopoiesis (CH), lead to a gain of function of PPM1D/Wip1 phosphatase, impairing p53-dependent G1 checkpoint and promoting cell proliferation. The presence of PPM1D mutations has been correlated with reduced response to standard chemotherapy in lymphoma patients. In this study, we analyzed the impact of low-frequency PPM1D mutations on the safety and efficacy of CD19-targeted CAR T-cell therapy in a cohort of 85 r/r DLBCL patients. In this cohort, the prevalence of PPM1D gene mutations was 20% with a mean variant allele frequency (VAF) of 0.052 and a median VAF of 0.036. CAR T-induced cytokine release syndrome (CRS) and immune effector cell-associated neuro-toxicities (ICANS) occurred at similar frequencies in patients with and without PPM1D mutations. Clinical outcomes were globally worse in the PPM1D mutated (PPM1Dmut) vs. PPM1D wild type (PPM1Dwt) subset. While the prevalent treatment outcome within the PPM1Dwt subgroup was complete remission (56%), the majority of patients within the PPM1Dmut subgroup had only partial remission (60%). Median progression-free survival (PFS) was 3 vs. 12 months (p = 0.07) and median overall survival (OS) was 5 vs. 37 months (p = 0.004) for the PPM1Dmut and PPM1Dwt cohort, respectively. Our data suggest that the occurrence of PPM1D mutations in the context of CH may predict worse outcomes after CD19-targeted CAR T-cell therapy in patients with r/r DLBCL.

Abstract A041: Rejuvenation: Innovative technology to improve T-cell antitumor properties through partial reprogramming

Abstract The T-cell identity and age determine function and fitness over a T-cell’s lifespan. This is particularly relevant when T cells are derived from patients with chronic viral infection or cancer. It is well known that increased T-cell age and differentiation and increased effector and exhausted phenotypes are associated with reduced anti-tumor efficacy and the need for higher infusion T-cell numbers for the treatment of hematological or solid tumors during adoptive cell therapies (ACT) (Kishton 2022). In an effort to overcome these barriers, methods to de-differentiate T cells into induced pluripotent stem cells (iPSCs) that return to embryonic immaturity, but lose their functional identity, have been extensively explored in the past years. Early work revealed several challenges to re-differentiate iPSCs into T cells with the desired functional phenotype, requiring a complex and time-consuming process. Here, we bring our novel strategy that counters the impact of aging on T-cell function through cellular rejuvenation without de-differentiating to iPSCs. We achieved T-cell rejuvenation via partial reprogramming of aged T cells by transiently expressing transcription factors associated with iPSC reprogramming. This proprietary partial reprogramming methodology reduces epigenetic age and rejuvenates T cells while maintaining the phenotype and function of conventional T cells.  We were the first to illustrate the ability to reduce the epigenetic age of T cells without fully de-differentiating to iPSCs. Our initial studies with PBMCs showed a significant reduction in epigenetic age. On subsequent RNAseq analyses, we observed that rejuvenated and conventional T cells have equivalent transcriptomes, suggesting the maintenance of identity. Functionally, the TRJ cells are characterized by greatly improved cell-expansion capacity, together with increased expression of markers associated with T-cell stemness, including CCR7 and CD62L. In vitro studies of NY-ESO-1-targeted T-cell receptor (TCR) or a CD19-targeted chimeric antigen receptor (CAR) TRJ cells exhibited improved antitumor properties compared with non-rejuvenated T-cell control (TCT) cells in sequential cell-killing assays. We also confirmed the enhanced in vivo antitumor efficiency of NY-ESO-1 TCR TRJ cells in a murine xenograft tumor model. When tumor-infiltrating lymphocytes (TILs) are rejuvenated with the same rejuvenation technology the TILs showed enhanced cell-expansion capacity, and improvements in T-cell stemness phenotype. These results suggest the potential application of T-cell rejuvenation across multiple adoptive T-cell therapeutic modalities and may potentially improve outcomes for patients with solid tumors. Citation Format: Jessica Fioravanti, Yasuhiro Yamazaki, Takuya Maeda, Yin Huang, Naritaka Tamaoki, Kriti Bahl, Burak Kutlu, Shobha Potluri, Gary Lee, Nicholas P Restifo, Raul Vizcardo. Rejuvenation: Innovative technology to improve T-cell antitumor properties through partial reprogramming [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2023 Oct 1-4; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Cancer Immunol Res 2023;11(12 Suppl):Abstract nr A041.

Enhancing brain entry and therapeutic activity of chimeric antigen receptor T cells with intra-arterial NEO100 in a mouse model of CNS lymphoma.

Malignancies of the CNS are difficult to treat because the blood-brain barrier (BBB) prevents most therapeutics from reaching the intracranial lesions at sufficiently high concentrations. This also applies to chimeric antigen receptor (CAR) T cells, for which systemic delivery is inferior to direct intratumoral or intraventricular injection of the cells. The authors previously reported on a novel approach to safely and reversibly open the BBB of mice by applying intra-arterial (IA) injections of NEO100, a pharmaceutical-grade version of the natural monoterpene perillyl alcohol. The authors hypothesized that this method would enable enhanced brain entry and therapeutic activity of intravenously delivered CAR T cells, which the authors tested in a mouse model of CNS lymphoma. Human Raji lymphoma cells were implanted into the brains of immune-deficient mice. After tumor uptake was confirmed with bioluminescent imaging, 0.3% NEO100 was injected intra-arterially, which was followed by intravenous (IV) delivery of CD19-targeted CAR T cells. After this single intervention, tumor growth was monitored with imaging, long-term survival of mice was recorded, and select mice were euthanized to analyze the distribution of CAR T cells in brain tissue. Intravenously injected CAR T cells could be readily detected in brain tumor areas after IA injection of NEO100 but not after IA injection of the vehicle (without NEO100). Although all untreated control animals died within 3 weeks, all mice that received IA NEO100 followed by IV CAR T cells survived and thrived for 200 days, when the experiment was terminated. Of the mice that received IV CAR T cells without prior IA NEO100, 3 died within 3 weeks and 2 survived long-term. BBB opening by IA NEO100 facilitates brain entry of intravenously delivered CD19 CAR T cells. The long-term survival of all mice with CNS lymphoma, along with the disappearance of the tumor as determined with imaging, suggests that this one-time therapeutic intervention was curative. BBB opening by IA NEO100 may offer a novel option to increase brain access by CAR T cells.

CD19-Targeted CAR-T Cells in Refractory Systemic Autoimmune Diseases: A Monocentric Experience from the First Fifteen Patients

Background: CD19-targeting chimeric antigen receptor (CAR) T cells are highly efficient in B cell malignancies. However, CD19 CAR T cells also target autoreactive B cells that trigger autoimmune diseases (AID) including systemic lupus erythematosus (SLE), idiopahtic inflammatory myositis (IIM) and systemic sclerosis (SSc). Achieving long-term remission in AID with standard therapy remains challenging and usually necessitates long-term treatment. Aim: To test whether CD19 CAR T cells achieve a deeper reset of B cells, eradicate autoimmunity, and achieve lasting drug-free remission in autoantibody-dependent AID. Methods: Patients with treatment-refractory SLE, IIM and SSc were eligible if they had signs of active organ involvement, failure of multiple immunomodulatory therapies, and serious or immediately life-threatening disease. CAR T cell therapy was offered via an expanded access program. Autologous CD19 CAR T cells MB-CART19.1 were produced with the Miltenyi prodigy platform. After leukapheresis on day -13, manufacturing commenced in house and lymphodepletion was started with fludarabine 25 mg/m2/d intravenously (i.v.) on days -5 to -3 and cyclophosphamide 1000 mg/m2/d i.v. on day -3. On day 1, all patients received 1x106 CAR T cells / kg body weight. Results: 15 patients (8 SLE, 4 SSc, and 3 IIM) were apheresed and were treated with a single infusion of CD19 CAR T cells. Median disease duration before CAR T was 3 years [1-20], median follow-up after CAR T was 12 months [2-28]. All patients failed on a median of 5 [2-14] previous treatments. Except for a maximum of 10 mg prednisolone daily, all immunomodulatory drugs were stopped prior to leukapheresis. After infusion, CAR T cells rapidly expanded till day 8.6 ± 0.8. CD19+ B cells were rapidly eliminated from peripheral blood after a mean of 5.9 ± 2.2 days. In 12/15 patients, B cells reoccurred at day 111±50. The last three patients with 77, 51 and 16 days follow-up are still B cell aplastic. All 8 SLE patient reached a complete remission after 3 months and maintain a SLE Disease Activity Index (SLEDAI) of 0 since. 3/3 IIM patients experienced major improvement and normalization of CK after 3 months which is ongoing. Of 4 SSc patients, 3 patients with >3 months follow-up show a decreased disease activity by EULAR AI by -4.3 [-4.3; -3.6]. All 15 patients entirely stopped immunosuppressive drugs. Overall safety of CAR T Cell therapy in AID was very favourable with cytokine-release syndrome (CRS) of grade 0 in 4, grade 1 in 10, and grade 2 in 1 patient. 6/15 patients received tocilizumab. One grade 1 immune-effector cell associated neurotoxicity syndrome (ICANS) presented as vertigo two weeks after CAR T infusion. No prolonged (>28 days) bone marrow suppression occurred. The Five SLE patients with a follow-up of 14-24 months stayed in remission despite reconstitution of B cells. In line, complement factor C3 stayed normal, proteinuria remained absent or at very low levels, and autoantibody seroconversion persisted. IgG responses to standard vaccines remained stable up to month 24 and were boosted by re-vaccination. Total B cell numbers gradually increased to a median of 230 cells/µl [183; 886] at month 12 and were mostly of a naïve phenotype. The early drop of CD19+CD27+ memory B cells increased again at month 12 indicating maturation of the B cells emerging after CAR T treatment. Conclusion: CD19 CAR T cells induce persistent, drug-free remission in three distinct autoantibody dependent AID with very good tolerability. Though hypothetical cure appears possible, longer follow up is needed. This unprecedented drug-free remission is remarkable as B cells functionally reconstitute. An investigator-initiated trial is currently expanding our experience of efficacy and safety.