Chimeric Antigen Receptor Therapy Research Articles

Application and progress of CAR therapy on malignances: from CAR-T to CAR-NK

For some malignances that are highly aggressive and metastatic are usually considered incurable. However, with the advent of immunotherapy, this therapy could be possibly effective after other three major therapies: surgery, radiation, chemotherapy. As an emerging immunotherapy, chimeric antigen receptor (CAR) T cells have been applied to treat hematologic malignances and some patients achieved long-term remission and temporary cure. However, CAR-T cells also bring side effects such as cytokine release syndrome (CRS), neurotoxicity, etc. Moreover, CAR-T cells did not perform well in solid tumors, for the reason that CAR-T cells are difficult to break through external barrier of solid tumors, at the same time maintain cytotoxicity and persistence inside. Therefore, we introduce CAR-NK cells therapy on the basis of CAR-T cells. At present all CAR-NK cell therapies are in clinical trials, its effectiveness has been initially observed. Compared with CAR-T cells, patients with hematologic malignances received CAR-NK cell therapies showed few side effects such as CRS and neurotoxicity.

Targeting pathogenic CD8+ tissue-resident T cells with chimeric antigen receptor therapy in murine autoimmune cholangitis

Primary biliary cholangitis (PBC) is a cholestatic autoimmune liver disease characterized by autoreactive T cell response against intrahepatic small bile ducts. Here, we use Il12b-/-Il2ra-/- mice (DKO mice) as a model of autoimmune cholangitis and demonstrate that Cd8a knockout or treatment with an anti-CD8α antibody prevents/reduces biliary immunopathology. Using single-cell RNA sequencing analysis, we identified CD8+ tissue-resident memory T (Trm) cells in the livers of DKO mice, which highly express activation- and cytotoxicity-associated markers and induce apoptosis of bile duct epithelial cells. Liver CD8+ Trm cells also upregulate the expression of several immune checkpoint molecules, including PD-1. We describe the development of a chimeric antigen receptor to target PD-1-expressing CD8+ Trm cells. Treatment of DKO mice with PD-1-targeting CAR-T cells selectively depleted liver CD8+ Trm cells and alleviated autoimmune cholangitis. Our work highlights the pathogenic role of CD8+ Trm cells and the potential therapeutic usage of PD-1-targeting CAR-T cells.

The use of T-cells with chimeric antigen receptor (CAR-T) in combination with chemotherapy and radiotherapy for the treatment of solid tumors

The introduction of chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of hematological diseases, particularly in combating blood cancer. The success of this cell therapy approach has led to the development of approximately seven commercial CAR-T based drugs. However, the application of CAR-T therapy for solid tumors has proven to be less effective due to challenges such as the varied antigens in solid tumors, an immunosuppressive tumor environment, limited immune cell infiltration, reduced CAR-T cell activity and toxicity issues. To solve these problems, scientists are making efforts to improve and improve the methods of treatment of solid tumors. Chemotherapy is the standard treatment for a large number of malignant neoplasms. It is also used before starting cell therapy for lymphodepletion and better engraftment of injected CAR-T cells. It has been shown that chemotherapy can reduce the immunosuppressive effect of the tumor microenvironment, destroy the stroma, and promote better infiltration of the tumor by CAR-T cells, improving their survival, persistence, cytotoxicity, and influencing the metabolism of immune cells inside the tumor. The effectiveness of combining chemotherapy and CAR-T cell therapy relies on various factors such as tumor type, dosage, treatment schedule, CAR-T cell composition, and individual biological traits. Similarly, radiation therapy can enhance tumor cell vulnerability to specific treatments while also supporting tumor cell survival.In this review, we discuss the use of CAR-T therapy to combat solid tumors, regarding the challenges of treating solid tumors, ways to overcome them, and also touch upon the possibility of using combination treatments to improve the effectiveness of cell therapy.

Abstract LB245: Single cell guided identification of logic-gated cell surface combinations for selective and safe CAR therapy design

Abstract The advancement of chimeric antigen receptor (CAR) T-cell therapy has been groundbreaking in the treatment of hematological malignancies. However, its application in solid tumors is constrained by antigen variability and unintended off-tumor, on-target toxicities. Addressing these issues, we introduce a genetic algorithm to analyze single-cell transcriptomics data from patient tumors. This method pinpoints sets of surface antigens exclusive to cancer cells, utilizing the logical operators "AND," "OR," and "NOT." Our technique scales to gene combinations of any size and exhibits robust performance across diverse parameter settings. When applied to five breast cancer datasets, this algorithm successfully uncovered triplet antigen combinations superior to current clinical single antigen targets in distinguishing between cancerous and healthy cells. This strategy offers a promising pathway toward the design of more selective and safe CAR therapies. Citation Format: Sanna Madan, Tiangen Chang, Binbin Wang, Saugato Rahman Dhruba, Alejandro A. Schäffer, Eytan Ruppin. Single cell guided identification of logic-gated cell surface combinations for selective and safe CAR therapy design [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 LB245.

Applications and opportunities for immune cell CAR engineering in comparative oncology.

Chimeric antigen receptor (CAR) T adoptive cell therapy has transformed the treatment of human hematologic malignancies. However, its application for the treatment of solid tumors remains challenging. An exciting avenue for advancing this field lies in the use of pet dogs, in which cancers that recapitulate the biology, immunological features, and clinical course of human malignancies arise spontaneously. Moreover, their large size, outbred genetic background, shared environment with humans, and immunocompetency make dogs ideal for investigating and optimizing CAR therapies before human trials. Here, we will outline how challenges in early clinical trials in canine lymphoma patients, including issues related to autologous CAR-T cell manufacturing, limited CAR-T cell persistence, and tumor antigen escape, mirrored challenges observed in human CAR-T trials. We will then highlight emerging adoptive cell therapy strategies currently under investigation in dogs with hematological and solid cancers, that will provide crucial safety and efficacy data on novel CAR-T regimens that can be used to support clinical trials. By drawing from ongoing studies, we will illustrate how canine patients with spontaneous cancer may serve as compelling screening platforms to establish innovative CAR-therapy approaches and identify predictive biomarkers of response, with a specific emphasis on solid tumors. With increased funding for canine immunotherapy studies, multi-institutional investigations are poised to generate highly impactful clinical data that should translate into more effective human trials, ultimately benefiting both human and canine cancer patients.

Abstract 44: A novel, codon-based method to modulate off-tumor toxicity of chimeric antigen receptor (CAR) T cells

Abstract Chimeric antigen receptor (CAR) T cell therapies for hematologic malignancies, while promising and efficacious, can also result in a variety of adverse effects. Of note, on-target, off-tumor toxicity is one adverse effect that continues to limit the safety and efficacy of CAR-T cells and has even led to life-threatening or fatal outcomes in patients (Morgan et al. 2010.). To address this, we have developed a unique, codon-based approach by replacing strategically selected codons within CAR non-antigen binding domains with their rare synonymous isoforms. Hoekema et al. (1987) reported the ability of synonymous rare codons to alter gene and protein expression in other model systems. In CAR-T cells, we aim to use this novel, codon-based approach to fine tune and modulate CAR-T cell expression and function to elicit full on-tumor activity while lessening off-tumor toxicity. In our approach, we replaced specific endogenous codons within the non-antigen binding domains of Hu8F4-CAR, a TCR-like 2nd generation CAR developed by our group which targets the leukemia-associated antigen PR1/HLA-A2 (Ma et al. 2016.). Briefly, we created variants of Hu8F4-CAR containing rare codon substitutions in two subtypes: intracellular-based (type 1) and combined extracellular- and intracellular-based (type 2). Each variant subtype (type 1 or 2) had either between 6 and 30 or 27 and 57 rare codons introduced, respectively. Expression profiling and functional assessment of the Hu8F4-CAR variants was assessed in the Jurkat mutant cell line (J.RT3-T3.5) or human primary healthy peripheral blood mononuclear cells (PBMCs) that were enriched for T cells, respectively. Expression profiling results show that surface expression is reduced in J.RT3-T3.5 cells when assessed by flow cytometry by 1-1.5-fold compared to unmodified Hu8F4-CAR. When evaluated by immunoblotting, novel lower molecular weight bands emerge only in rare codon-modified variants, suggesting that rare codons may have altered translational or post-translational processing leading to truncated CAR protein isoforms (30, 45, or 60kDa vs 73kDa for unmodified Hu8F4-CAR), which may contribute to reduced cell surface CAR expression. Furthermore, we have conducted in vitro functional testing of the rare codon-modified variants and show reduced activity against non-malignant off-tumor targets that express PR1 and/or HLA-A2 including healthy donor PBMCs, mobilized hematopoietic cells, and bone marrow. Importantly, in addition to reduced off-tumor activity against healthy myeloid cells, rare codon-modified variants preserve their activity against on-tumor target cells, including the U937-A2+ cell line and primary acute myeloid leukemia. Altogether, these results suggest that our approach can modulate CAR expression and functionality creating a novel methodology to reduce the likelihood of off-tumor adverse effects typically associated with CAR therapies. Citation Format: Rolando A. Vedia, Sijie Lu, Anne V. Philips, Anna Sergeeva, Lisa S. St John, Karen Clise-Dwyer, Gheath Alatrash, Jeffrey J. Molldrem. A novel, codon-based method to modulate off-tumor toxicity of chimeric antigen receptor (CAR) T cells [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 44.

Abstract 4019: Development of mRNA chimeric antigen receptor T cells targeting MET in aggressive B-cell lymphomas

Abstract Multiple versions of CAR T cells targeting the cell surface protein CD19 are approved by the FDA to treat refractory B-cell malignancies. However, durable remissions range from 60% in B-cell leukemias to 40% in B-cell lymphomas. Major reasons for resistance to CD19-CAR treatment relate to heterogeneous or loss of CD19 expression. In addition, CD19-CAR leads to B-cell depletion which increases the risk for infection. These limiting factors necessitate research into alternative targets for CAR therapy against B-cell lymphomas.Using a large data set from clinical trials, we found that approximately 30-70% of diffuse large B-cell lymphomas (DLBCL) express MET. We hypothesize that these MET-positive B-cell lymphomas can potentially be targeted with chimeric antigen receptor (CAR) T-cells against MET receptor. We constructed a second-generation anti-MET-CAR by fusing the scFv fragment of an anti-MET monoclonal antibody with the human CD28 hinge/transmembrane/cytoplasmic domain and CD3ζ cytoplasmic domain. Stable MET-CAR Jurkat cells showed increased CD69 expression upon stimulation by MET-positive lymphoma cell lines such as Karpas-422 and OCI-LY3. Using primary human T cells, we further demonstrated that the mRNA MET-CAR T-cells mediated cytotoxicity against DLBCL cell lines. Of note, while CD19-CAR T-cells showed only low level of cytotoxicity against the CD19-/MET+ OCI-LY3 cell line, MET-CAR T cell was able to mediate substantial tumor cell lysis.In summary, the preliminary data demonstrate that MET-CAR is capable of mediating cytotoxicity against MET-positive DLBCL. Some cell lines such as OCI-LY3 are negative for CD19 but positive for MET expression, and MET-CAR is capable of mediating cell lysis while CD19-CAR is ineffective. These results suggest that some large B-cell lymphomas negative for CD19, either intrinsic or secondary to loss of CD19 as a result of resistance mechanism, may show MET expression and will likely benefit from MET-targeted immunotherapy. Citation Format: Po-Han Chen, Rianna Raghunandan, Markus Muschen, Samuel G. Katz. Development of mRNA chimeric antigen receptor T cells targeting MET in aggressive B-cell lymphomas [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 4019.

Abstract 3617: Expansion and persistence of anti-BCMA CAR T cells correlates with durability of responses in multiple myeloma patients

Abstract Background: Chimeric antigen receptor (CAR) T cells targeting B-cell maturation antigen (BCMA) can induce >70% response rates in patients with relapsed/refractory multiple myeloma (RRMM). However, most patients ultimately relapse. There are two FDA-approved CAR T products: ciltacabtagene autoleucel (cilta-cel) and idecabtagene vicleucel (ide-cel), the former having much more durable responses. The mechanisms that mediate more durable responses with these CAR T cells is unknown. Previous studies have shown that specific cell states in the apheresis and infusion products are associated with long-term efficacy of anti-BCMA CAR therapy in MM and the relationship between durability of response and CAR T cell persistence remains unclear. Methods: We analyzed serial bone marrow and PBMC samples from 20 MM patients who received BCMA CAR T therapy, including cilta-cel, ide-cel, and JCARH125. Flow cytometry and single-cell RNAseq were used to evaluate the features of CAR T cells that are associated with durable clinical responses. Results: While CAR T cells were detectable but variable among patients at 1-month post infusion, the frequency of CAR T cells in bone marrow at 1-month post-infusion is positively correlated with progression free survival (PFS) in all MM patients (p=0.009). This association was also evident in patients just treated with cilta-cel (p= 0.008). By 6 months, CAR T cells could still be detected by high-throughput flowcytometry in the cilta-cel-treated patients, but CAR T cells were not detectable in most of the patients receiving the other 2 products. Cilta-cel CAR T cells predominantly possessed an effector-like surface phenotype at 1-moth post infusion in both CD8+ and CD4+ compartments in bone marrow. These CAR T cells shifted to effector memory and central memory T cell states by 6 months, respectively. For ide-cel and JCARH125, patients with more durable responses (>6mos) there was a significantly higher proportion of CAR T cells with CD8+ effector memory-like state at 1-month post infusion. Conclusions: Our data demonstrate that distinct anti-BCMA CAR T cell treatments lead to very different cellular outcomes: Cilta-cel CAR T cell treatment leads to greater expansion and persistence compared to other anti-BCMA CAR T cells. Cilta-cel CAR T cells also shift from the initial effector state to a memory phenotype. These results provide insights into features of more efficacious anti-BCMA CAR T cells that can help guide the future development of more durable treatments for MM. Citation Format: Kai Wu, Karen Law, Guy Ledergor, Chang Liu, Zenghua Fan, Vibha Gurunathan, Averey Lea, Matthew Clark, Serena Kwek, Alexander Cheung, Jeffrey Wolf, Ajai Chari, Anupuma Kumar, Justin Eyquem, Thomas Martin, Lawrence Fong. Expansion and persistence of anti-BCMA CAR T cells correlates with durability of responses in multiple myeloma patients [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 3617.

Stem cell-derived CAR T cells show greater persistence, trafficking, and viral control compared to ex vivo transduced CAR T cells

Adoptive cell therapy (ACT) using T cells expressing chimeric antigen receptors (CARs) is an area of intense investigation in the treatment of malignancies and chronic viral infections. One of the limitations of ACT-based CAR therapy is the lack of in vivo persistence and maintenance of optimal cell function. Therefore, alternative strategies that increase the function and maintenance of CAR-expressing T cells are needed. In our studies using the humanized bone marrow/liver/thymus (BLT) mouse model and nonhuman primate model (NHP) of HIV infection, we evaluated two CAR-based gene therapy approaches. In ACT approach, we utilized cytokine enhancement and preconditioning to generate greater persistence of anti-HIV CAR+ T cells. We observed limited persistence and expansion of anti-HIV CAR T cells which led to minimal control of the virus. In our stem-cell based approach, we modified hematopoietic stem/progenitor cells (HSPCs) with anti-HIV CAR to generate anti-HIV CAR T cells in vivo. We observed CAR-expressing T cell expansion which led to better plasma viral load suppression. HSPC-derived CAR cells in infected NHPs showed superior trafficking and persistence in multiple tissues. Our results suggest a stem cell-based CAR T cell approach may be superior to generate long-term persistence and functional antiviral responses against HIV infection.

Recent progress in chimeric antigen receptor therapy for acute myeloid leukemia.

Although CAR-T cell therapy has been particularly successful as a treatment for B cell malignancies, effectively treating acute myeloid leukemia with CAR remains a greater challenge. Multiple preclinical studies and clinical trials are underway, including on AML-related surface markers that CAR-T cells can target, such as CD123, CD33, NKG2D, CLL1, CD7, FLT3, Lewis Y and CD70, all of which provide opportunities for developing CAR-T therapies with improved specificity and efficacy. We also explored specific strategies for CAR-T cell treatment of AML, including immune checkpoints, suicide genes, dual targeting, genomic tools and the potential for universal CAR. In addition, CAR-T cell therapy for AML still has certain risks and challenges, including cytokine release syndrome (CRS) and haematotoxicity. Despite these challenges, as a new targeting method for AML treatment, CAR-T cell therapy still has great prospects. Ongoing research aims to further optimize this treatment mode.

Application of chimeric antigen receptor therapy beyond oncology: A bibliometric and visualized analysis

PurposeChimeric antigen receptor therapy beyond oncology has gained increasing attention. While a substantial number of publications have emerged in recent years, there has been a paucity of conducted bibliometric studies. Our objective is to systematically summarize and visually analyze the literature in the field of chimeric antigen receptors therapy beyond oncology and explore hotspots in this field. MethodsWeb of Science Core Collection was selected as the data source, and the data was retrieved on December 23, 2022, according to the search strategy. CiteSpace 6.1.R6 and Vosviewer 1.6.18 were used to analyze publications and explore research hotspots and directions. ResultsA total of 338 publications written by 1832 authors from 516 institutions in 42 countries/regions were selected for the analysis. The number of publications is steadily increasing annually. The United States emerged as the primary contributor, and University of Pennsylvania was the leading institution. Frontiers in Immunology boasted the highest number of published papers. Kitchen SG, Riley JL, and Scott DW were the most productive researchers in this field. The keyword cluster analysis identified HIV, autoimmune diseases, transplant related diseases and COVID-19 as the primary focus areas within the realm of chimeric antigen receptor therapy beyond oncology. ConclusionThe advancement of chimeric antigen receptor therapy beyond oncology has witnessed rapid progress in recent years. We have explored the hotspots and research directions in this field. It is hoped that this study could provide references and directions for future clinical researches.

Evolving Transplantation Patterns for Mantle Cell Lymphoma in the Era of Chimeric Antigen Receptor Therapy.

Evolving Transplantation Patterns for Mantle Cell Lymphoma in the Era of Chimeric Antigen Receptor Therapy.

The SpyCatcher-SpyTag interaction mediates tunable anti-tumor cytotoxicity of NK cells

Chimeric antigen receptor (CAR)-modified T and NK cell immunotherapy is a promising approach for cancer treatment. Due to the lack of tunability in anti-tumor activity, conventional CAR therapies have limited efficacy at low tumor antigen densities. To tune the CAR response to tumor cell surface antigens, we have developed a split CAR using the SpyCatcher-SpyTag system. The SpyCatcher serves as the ectodomain to constitute a SpyCatcher-CAR (SpyCAR), while SpyTag is attached to the antibodies that recognize tumor antigens. With dimerization mediated by SpyCatcher and SpyTag, the number and activation level of SpyCARs recruited by tumor antigens depends on the SpyTag number in the “antibody-SpyTag” fusion protein. The results demonstrated that the increasing number of SpyTags effectively enhanced the cytotoxicity of SpyCAR-NK92 cells against target cells. The development of SpyCAR with tunable cytotoxicity provides a novel strategy for CAR-based tumor immunotherapies.

T-cell redirection therapy after allogeneic stem cell transplantation in multiple myeloma: When the cure fails!

Allogeneic stem cell transplant remains an option for patients with myeloma. Given the unfortunate inevitability of the majority of patients, relapsing salvage therapy options are needed. Although there is a potential concern for subsequent T-cell redirection therapy in these patients, Hammons etal. provide a retrospective look at patients treated this way with no new significant adverse safety or efficacy signal. Commentary on: Hammons etal. Chimeric antigen receptor and bispecific T-cell engager therapies in multiple myeloma patients with prior allogeneic transplantation. Br J Haematol 2024;204:887-891.

Determinants of outcomes and advances in CD19-directed chimeric antigen receptor therapy for B-cell acute lymphoblastic leukemia.

Relapsed and refractory B-cell acute lymphoblastic leukemia (B-ALL) is an aggressive B-cell neoplasm associated with poor outcomes. Conventional multiagent chemotherapy and bispecific antibody therapy may induce remission; however, relapse rates remain high and overall survival is poor. Chimeric antigen receptor T-cell (CAR-T) therapy provides durable, deep complete remission, and long-term cures in relapsed and refractory B-ALL. However, with this new treatment modality, 10%-30% of patients do not achieve remission, and over 50% experience relapse after therapy. Currently, there are two approved CD19-specific CAR-T cell constructs in B-ALL, Tisagenlecleucel and Brexucabtagene Autoleucel by the United States Food and Drug Administration, and the European Medicines Agency (EMA). In this review, we discuss patients, disease, and CAR-T predictors of outcomes in B-ALL. We describe the two approved CD19-directed CAR-T cell products, review the current literature, and discuss factors associated with high risks of therapy failure and future direction in CAR-T cell therapy for B-ALL.

Cytokine Modification of Adoptive Chimeric Antigen Receptor Immunotherapy for Glioblastoma.

Chimeric antigen receptor (CAR) cell-based therapies have demonstrated limited success in solid tumors, including glioblastoma (GBM). GBMs exhibit high heterogeneity and create an immunosuppressive tumor microenvironment (TME). In addition, other challenges exist for CAR therapy, including trafficking and infiltration into the tumor site, proliferation, persistence of CARs once in the tumor, and reduced functionality, such as suboptimal cytokine production. Cytokine modification is of interest, as one can enhance therapy efficacy and minimize off-target toxicity by directly combining CAR therapy with cytokines, antibodies, or oncolytic viruses that alter cytokine response pathways. Alternatively, one can genetically modify CAR T-cells or CAR NK-cells to secrete cytokines or express cytokines or cytokine receptors. Finally, CARs can be genetically altered to augment or suppress intracellular cytokine signaling pathways for a more direct approach. Codelivery of cytokines with CARs is the most straightforward method, but it has associated toxicity. Alternatively, combining CAR therapy with antibodies (e.g., anti-IL-6, anti-PD1, and anti-VEGF) or oncolytic viruses has enhanced CAR cell infiltration into GBM tumors and provided proinflammatory signals to the TME. CAR T- or NK-cells secreting cytokines (e.g., IL-12, IL-15, and IL-18) have shown improved efficacy within multiple GBM subtypes. Likewise, expressing cytokine-modulating receptors in CAR cells that promote or inhibit cytokine signaling has enhanced their activity. Finally, gene editing approaches are actively being pursued to directly influence immune signaling pathways in CAR cells. In this review, we summarize these cytokine modification methods and highlight any existing gaps in the hope of catalyzing an improved generation of CAR-based therapies for glioblastoma.

Chimeric antigen receptor and bispecific T-cell engager therapies in multiple myeloma patients with prior allogeneic transplantation.

Chimeric antigen receptor T-cell (CAR-T) therapy and bispecific T-cell engagers (BsAb) have emerged as promising immunotherapeutic modalities in patients with relapsed and/or refractory multiple myeloma (RRMM). However, there is limited data on the safety and efficacy of CAR-T and BsAb therapies in MM patients with a prior history of allogeneic transplantation (allo-HCT). Thirty-three MM patients with prior allo-HCT received CAR-T (n = 24) or BsAb (n = 9) therapy. CAR-T therapy demonstrated an ORR of 92% (67% ≥ CR), and 73% were MRD negative. BsAb therapy resulted in an ORR of 44% (44% ≥ CR) and 44% MRD negative. Safety analysis showed grade ≥3 AEs in 92% of CAR-T and 56% of BsAb patients. Cytokine release syndrome (CRS) occurred in 83% of CAR-T and 78% of BsAb recipients, while immune effector cell-associated neurotoxicity syndrome (ICANS) was observed in three CAR-T patients. Infections of grade ≥3 were reported in 50% of CAR-T and 44% of BsAb recipients. No exacerbation of graft-versus-host disease occurred except in one BsAb recipient. CAR-T and BsAb therapies appear to be feasible, safe and provide deep and durable responses in MM patients with prior allo-HCT.

A Pragmatic Approach to Navigating FDA Guidance for Therapeutic Product Development in Malignant Hematological Disease

Background: Owing to the unique therapeutic characteristics and diverse etiology of underlying disease, navigating available regulatory guidance can be a challenge for newcomers to therapeutic research and development (R&D). Further, classes of drugs and biologic products are regulated separately by the U.S. Food and Drug Administration (FDA) centers CBER and CDER, respectively. Methods: We provide background on the FDA guidance structure herein and further examine publicly registered clincialtrials.gov data to provide an overview of development status by phases and novel modality (i.e., CAR-T) in context of the regulatory landscape. Results: Therapeutic products developed for malignant hematological disease can be regulated by either CDER or CBER depending on the type of drugs, ranging from small molecules to macromolecules, including cellular and gene therapies. In 2019, CDER of Hematology and Oncology Products (OHOP) has been reorganized and renamed the Office of Oncologic Diseases (OOD). The new OOD structure consists of six divisions including Division of Hematologic Malignancies 1 (DHM1) and Division of Hematologic Malignancies 2 (DHM2) for the review of hematologic malignancies. In 2022, CBER of Office of Tissues and Advanced Therapies (OTAT) was transformed into the Office of Therapeutic Products (OTP) to address the exponential growth in cell and gene therapies. PDUFA VII expanded the INTERACT meeting program to include both centers, a major change that may drive early phase development collaboration. A review on the current state of hematologic malignancies clinical trials in USA shows that, of 301 hematologic malignancies related trails in USA registered to ClinicalTrials.gov (Fig. 1), 4 are in early phase 1(exploratory phase), 126 in phase 1, 120 in phase 2, 18 in phase 3, and 1 in phase 4. Most of the trials are still in early phases 1 or 2. Among the 301 registered clinical trials, 21 of clinical trials (Fig. 2) are CAR-T related, and 10 of the trials are gene modified cell products related. Conclusions: Compared with traditional treatment on malignant hematological disease, immunotherapy is the upcoming trend in cancer treatment. Chimeric antigen receptor (CAR) therapy is at the forefront of cellular/adoptive immunotherapy for cancer treatment due to its sustained remission and better quality of life. Much research and clinical trials have been undertaken in recent years which led to several successful outcomes in CAR therapy. Despite tremendous progress, CAR-T are still faced with many challenges, including evolving regulatory framework along the road. We summarize the regulatory landscape to assist therapy developers to align with FDA expectations.

Senza5 TM CART5: An Autologous CD5-Deleted Anti-CD5 CART Product with Enhanced Anti-T-Cell Lymphoma Activity

Introduction: Treatment with adoptive T cell therapies expressing Chimeric Antigen Receptors (CART) produces unprecedented clinical responses in relapsed or refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL), non-Hodgkin lymphomas (NHL), and multiple myeloma. Despite the transformative potential of these therapies for cancer, most patients treated with CART therapy experience incomplete responses or eventual relapse. Moreover, CART therapy is not yet effective for solid cancers or other hematological malignancies such as T-cell neoplasms. Thus, there is a dire need to enhance CART efficacy and extend this approach to more cancer types. We previously presented preliminary preclinical results of CD5-directed CAR-T cells (CART5) that had CD5 knocked out (KO) [ Blood (2020) 136 (Supplement 1): 51-52]. CD5 KO not only prevented CART fratricide but also dramatically enhanced CART function in multiple in vivo models. Enhanced CART function reflected disinhibition of early T-cell activation by abrogating CD5 signaling. Here, we combine the functional advantage of CD5 KO CART5 with a clinical-grade “rapid” 5-day manufacturing process, characterize the resulting drug product, and evaluate its in vivo antitumor efficacy in a human xenograft model of T-cell lymphoma/leukemia. Methods and Results: Using normal healthy donor T cells, we developed a proprietary, “rapid” 5-day GMP-validated manufacturing process for CD5 KO CART5, completing the process in 5 days (CART5 rapid) instead of the conventional 14+ days (CART5 conv). At the end of manufacturing, the two products possessed similar ratios of CD8 + and CD4 + T cells, CD5 editing, and CAR5 expression. The CART5 rapid product did not exhibit any genetic or functional abnormalities characteristic of tumorigenic risk, demonstrated by low off-target gene editing in low-risk genes, no in vitro soft agar colony formation, and normal karyotypes. Importantly, the CART5 rapid manufacturing process did not skew TCRβ profiles, indicating that the CART5 rapid product retains a diverse T-cell repertoire. CD5 KO CART5 rapid cells possessed high specificity for T-cell leukemia/lymphoma, reflected by the absence of recognition of ex vivo normal human cells (cardiomyocytes, hepatocytes, neurons, monocytes, etc). Interestingly, CD5 KO CART5 rapid cells possessed a more central memory-like phenotype than CD5 KO CART5 conv cells which has been correlated with improved clinical efficacy. To compare their antitumor efficacy, we performed an in vivo experiment with CD5 + Jurkat cells utilizing a suboptimal dose of CART5 cells. Immunodeficient NSG mice were engrafted with 10 6 Jurkat cells on day -7 and treated intravenously on day 0 with a suboptimal dose (0.5x10 6 CAR + cells) of CD5 KO CART5 rapid or CD5 KO CART5 conv cells. Controls received an equivalent total number of Mock KO UTD conv. Mice treated with CD5 KO CART5 rapid cells demonstrated superior antitumor responses compared to CD5 KO CART5 conv. Improved tumor control correlated with dramatically increased overall survival of mice treated with CD5 KO CART5 rapid (median overall survival Mock KO UTD = 21 days; CD5 KO CART5 conv = 44 days vs. CD5 KO CART5 rapid = not reached, p=0.0019, Mantel-Cox; Figure 1). Conclusion: This novel CD5 KO anti-CD5 CART product manufactured in a 5-day GMP process shows high specificity and significantly enhanced antitumor efficacy resulting from the synergistic effect of improved early T-cell activation due to CD5 deletion and preservation of T-cell memory phenotypes conferred by a novel, 5-day manufacturing processes. Autologous Senza5 TM CART5 for the treatment of CD5 + nodal T-cell lymphomas is expected to enter the clinic in a Phase I study later this year.

Unveiling Novel Therapeutic Targets for CAR Therapy in Multiple Myeloma through Single-Cell RNA Sequencing

Multiple Myeloma (MM) is a hematological malignancy characterized by the clonal proliferation of plasma cells. Among the different therapeutic options in this setting, chimeric antigen receptor (CAR) T cells recently showed unprecedent achievements in term of progression free survival. However, despite advancements in current therapies, the disease's heterogeneity remains a major challenge and all patients unavoidably relapse, rendering innovative approaches to identify precise therapeutic targets eagerly awaited. Along this line, the revolution of single-cell (sc) technologies brings new opportunities to identify precise therapeutic targets, including abundant and unique surface proteins for CAR therapy. In this study, by analyzing individual cancer cells at sc level, we aim to identify novel surface targets, facilitating the development of novel personalized cellular therapies as well as treatment sequences. To this end, we used samples collected from 9 publicly available single-cell RNA sequencing (scRNA-seq) datasets (GEO accession numbers: GSE176131, GSE189460, GSE223060, GSE210079, GSE145977, GSE124310, GSE161801, GSE163278, GSE161722) obtained from 156 patients affected by monoclonal gammopathies (19 monoclonal gammopathy of undetermined significance (MGUS), 10 smoldering multiple myeloma (SMM), 78 MM and 25 relapsed/refractory multiple myeloma (RRMM)) and 24 normal bone marrows (NBM), to conduct an unbiased search for genes showing specific expression in plasma cells (PCs), regardless of disease status. We found 15 genes showing differential expression in PCs (adj.pval<0.01 and logFC>1) and coding for surface proteins: TNFRSF17(BCMA), SDC1 (CD138), FCRL5 (GPRC5D), TNFRSF13B (TACI), CD38, SLAMF7 (CS1), CD59, FCGR2B, FGFR3, SLC44A1 (CTL1), CD320, FCRL2, IL15RA, INSR and SLAMF1. As expected, most of these molecules already represent critical therapeutic targets. After completing our initial analysis, we compared PCs transcriptomes from MM/RRMM patients with NBM, MGUS, and SMM samples. Among previously identified genes, CD320 only was significantly overexpressed in MM PCs. Next, we investigated associations between cytogenetic-related cell subclusters and previously identified surface markers. Interestingly, we found a significant association between the expression levels of TACI/CD59 and the overexpression of CCND2 and MAF, both associated with the presence of t(14:16). Next, we decided to focus on the first five genes (according to expression ranking) that do not currently have an active clinical development program in advanced phases, namely: TNFRSF13B, CD59, FCGR2B, SLC44A1, and CD320 (Fig. 1 A, values dichotomized based on their median) to uncover their (potential) impact/association with patient's outcome. In our analysis of different available expression profiling datasets (GSE4204, GSE2658, GSE57317, GSE4581, GSE4452, GSE9782, the CoMMpass study NCT01454297) involving around 2000 MM patients, we observed TNFRSF13B, CD59, and FCGR2B expression correlated with improved outcome while CD320 and SLC44A1 expression associated with worse outcome (Fig. 1 B). In conclusion, we integrated results from both scRNAseq and bulk-RNAseq/microarray data to identify new targets genes to be used in the context of personalized medicine. Interestingly, CD320 emerges as a potential candidate biomarker useful for monitoring disease evolution and predicting worse outcomes. Additionally, this approach led us to identify a series of potential new targets for MM patients, depicting a new scenario where each patient could be “screened” to identify the best molecule to be targeted. While further investigation is necessary to assess off-target toxicity and confirm clinical relevance, our analyses significantly streamline the search for tumor markers with a method potentially applicable to different malignancies, bringing us closer to identifying the best candidates for effective CAR therapy.