Multiplex Genome-Edited T-cell Manufacturing Platform for "Off-the-Shelf" Adoptive T-cell Immunotherapies

[Development of allogeneic CAR T-cells]

Chimeric antigen receptor (CAR) T-cell therapy represents a major breakthrough in the field of hematology. "Off-the-shelf" allogeneic CAR T-cells from donors have many potential advantages over autologous approaches, such as the immediate availability of cryopreserved batches, possible standardization of the cell product, time for multiple cell modifications, redosing and decreased cost. However, allogeneic T-cells possess foreign immunological identities that can lead to graft-versus-host disease (GvHD) and their rejection by the host immune system. In this review, we describe the different approaches to produce allogeneic CAR T-cells with limited potential for GvHD and that can persist in the recipient. The preliminary clinical results obtained with the first generation of allogeneic CAR T-cells are presented as well as the perspectives in hematological malignancies and solid tumors.

Genome Editing as a Vehicle to Drive Successful Chimeric Antigen Receptor T Cell Therapies to the Clinic

Chimeric antigen receptor (CAR) T cells have emerged as an effective therapy for patients with relapsed and refractory haematological malignancies. However, there are many challenges preventing clinical efficacy and thus broader translation of this approach. These hurdles include poor autologous T cell fitness, manufacturing issues and lack of conserved tumour-restricted antigens to target. Recent efforts have been directed toward incorporating genome editing technologies to address these challenges and develop potent CAR T cell therapies for a diverse array of haematopoietic cancers. In this review, the authors discuss gene editing strategies that have been employed to augment CAR T cell fitness, generate allogeneic ‘off-the-shelf’ CAR T cell products, and safely target elusive myeloid and T cell cancers that often lack appropriate tumour-specific antigens.

Multiplex CRISPR/Cas9 genome editing in hematopoietic stem cells for fetal hemoglobin reinduction generates chromosomal translocations

Sickle cell disease and β-thalassemia are common monogenic disorders that cause significant morbidity and mortality globally. The only curative treatment currently is allogeneic hematopoietic stem cell transplantation, which is unavailable to many patients due to a lack of matched donors and carries risks including graft-versus-host disease. Genome editing therapies targeting either the BCL11A erythroid enhancer or the HBG promoter are already demonstrating success in reinducing fetal hemoglobin. However, where a single locus is targeted, reliably achieving levels high enough to deliver an effective cure remains a challenge. We investigated the application of a CRISPR/Cas9 multiplex genome editing approach, in which both the BCL11A erythroid enhancer and HBG promoter are disrupted within human hematopoietic stem cells. We demonstrate superior fetal hemoglobin reinduction with this dual-editing approach without compromising engraftment or lineage differentiation potential of edited cells post-xenotransplantation. However, multiplex editing consistently resulted in the generation of chromosomal rearrangement events that persisted in vivo following transplantation into immunodeficient mice. The risk of oncogenic events resulting from such translocations therefore currently prohibits its clinical translation, but it is anticipated that, in the future, alternative editing platforms will help alleviate this risk.

Clustered regularly interspaced short palindromic repeats, a glimpse - impacts in molecular biology, trends and highlights

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is a novel molecular tool. In recent days, it has been highlighted a lot, as the Nobel prize was awarded for this sector in 2020, and also for its recent use in Covid-19 related diagnostics. Otherwise, it is an eminent gene-editing technique applied in diverse medical zones of therapeutics in genetic diseases, hematological diseases, infectious diseases, etc., research related to molecular biology, cancer, hereditary diseases, immune and inflammatory diseases, etc., diagnostics related to infectious diseases like viral hemorrhagic fevers, Covid-19, etc. In this review, its discovery, working mechanisms, challenges while handling the technique, recent advancements, applications, alternatives have been discussed. It is a cheaper, faster technique revolutionizing the medicinal field right now. However, their off-target effects and difficulties in delivery into the desired cells make CRISPR, not easily utilizable. We conclude that further robust research in this field may promise many interesting, useful results.

Current Limitations and Perspectives of Chimeric Antigen Receptor-T-Cells in Acute Myeloid Leukemia

Simple Summary

Acute myeloid leukemia (AML) is the most frequent type of acute leukemia in adults. Allogeneic hematopoietic cell transplantation (allo-HCT) has been the only potentially curative treatment for the majority of patients. The ability of chimeric antigen receptor (CAR)-modified T-cell therapy directed against the CD19 antigen to induce durable remissions in patients with acute lymphoblastic leukemia (ALL) has provided optimism that this novel treatment paradigm can be extrapolated to AML. In this review, we provide an overview of candidate target antigens for CAR-T-cells in AML, an update on recent progress in preclinical and clinical development of investigational CAR-T-cell products, and discuss challenges for the clinical implementation of CAR-T-cell therapy in AML.

Abstract

Adoptive transfer of gene-engineered chimeric antigen receptor (CAR)-T-cells has emerged as a powerful immunotherapy for combating hematologic cancers. Several target antigens that are prevalently expressed on AML cells have undergone evaluation in preclinical CAR-T-cell testing. Attributes of an ‘ideal’ target antigen for CAR-T-cell therapy in AML include high-level expression on leukemic blasts and leukemic stem cells (LSCs), and absence on healthy tissues, normal hematopoietic stem and progenitor cells (HSPCs). In contrast to other blood cancer types, where CAR-T therapies are being similarly studied, only a rather small number of AML patients has received CAR-T-cell treatment in clinical trials, resulting in limited clinical experience for this therapeutic approach in AML. For curative AML treatment, abrogation of bulk blasts and LSCs is mandatory with the need for hematopoietic recovery after CAR-T administration. Herein, we provide a critical review of the current pipeline of candidate target antigens and corresponding CAR-T-cell products in AML, assess challenges for clinical translation and implementation in routine clinical practice, as well as perspectives for overcoming them.

T Cell Engaging Immunotherapies, Highlighting Chimeric Antigen Receptor (CAR) T Cell Therapy

In the past decade, chimeric antigen receptor (CAR) T cell technology has revolutionized cancer immunotherapy. This strategy uses synthetic CARs to redirect the patient's own immune cells to recognize specific antigens expressed on the surface of tumor cells. The unprecedented success of anti-CD19 CAR T cell therapy against B cell malignancies has resulted in its approval by the US Food and Drug Administration (FDA) in 2017. However, major scientific challenges still remain to be addressed for the broad use of CAR T cell therapy. These include severe toxicities, limited efficacy against solid tumors, and immune suppression in the hostile tumor microenvironment. Furthermore, CAR T cell therapy is a personalized medicine of which the production is time- and resource-intensive, which makes it very expensive. All these factors drive new innovations to engineer more powerful CAR T cells with improved antitumor activity, which are reviewed in this manuscript.

Optimizing the Clinical Impact of CAR-T Cell Therapy in B-Cell Acute Lymphoblastic Leukemia: Looking Back While Moving Forward

Chimeric antigen receptor T-cell (CAR-T) therapy has been successful in creating extraordinary clinical outcomes in the treatment of hematologic malignancies including relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). With several FDA approvals, CAR-T therapy is recognized as an alternative treatment option for particular patients with certain conditions of B-ALL, diffuse large B-cell lymphoma, mantle cell lymphoma, follicular lymphoma, or multiple myeloma. However, CAR-T therapy for B-ALL can be surrounded by challenges such as various adverse events including the life-threatening cytokine release syndrome (CRS) and neurotoxicity, B-cell aplasia-associated hypogammaglobulinemia and agammaglobulinemia, and the alloreactivity of allogeneic CAR-Ts. Furthermore, recent advances such as improvements in media design, the reduction of ex vivo culturing duration, and other phenotype-determining factors can still create room for a more effective CAR-T therapy in R/R B-ALL. Herein, we review preclinical and clinical strategies with a focus on novel studies aiming to address the mentioned hurdles and stepping further towards a milestone in CAR-T therapy of B-ALL.

Gene editing to enhance the efficacy of cancer cell therapies

Adoptive T cell therapies have shown impressive signals of activity, but their clinical impact could be enhanced by technologies to increase T cell potency and diminish the cost and labor involved in manufacturing these products. Gene editing platforms are under study in this arena to (1) enhance immune cell potency by knocking out molecules that inhibit immune responses; (2) deliver genetic payloads into precise genomic locations and thereby enhance safety and/or improve the gene expression profile by leveraging physiologic promoters, enhancers, and repressors; and (3) enable off-the-shelf therapies by preventing alloreactivity and immune rejection. This review discusses gene editing approaches that have been the best studied in the context of human T cells and adoptive T cell therapies, summarizing their current status and near-term potential for translation.

Allogeneic CAR Invariant Natural Killer T Cells Exert Potent Antitumor Effects through Host CD8 T-Cell Cross-Priming

PURPOSE

The development of allogeneic chimeric antigen receptor (CAR) T-cell therapies for off-the-shelf use is a major goal that faces two main immunologic challenges, namely the risk of graft-versus-host disease (GvHD) induction by the transferred cells and the rejection by the host immune system limiting their persistence. In this work we assessed the direct and indirect antitumor effect of allogeneic CAR-engineered invariant natural killer T (iNKT) cells, a cell population without GvHD-induction potential that displays immunomodulatory properties.

EXPERIMENTAL DESIGN

After assessing murine CAR iNKT cells direct antitumor effects in vitro and in vivo, we employed an immunocompetent mouse model of B-cell lymphoma to assess the interaction between allogeneic CAR iNKT cells and endogenous immune cells.

RESULTS

We demonstrate that allogeneic CAR iNKT cells exerted potent direct and indirect antitumor activity when administered across major MHC barriers by inducing tumor-specific antitumor immunity through host CD8 T-cell cross-priming.

CONCLUSIONS

In addition to their known direct cytotoxic effect, allogeneic CAR iNKT cells induce host CD8 T-cell antitumor responses, resulting in a potent antitumor effect lasting longer than the physical persistence of the allogeneic cells. The utilization of off-the-shelf allogeneic CAR iNKT cells could meet significant unmet needs in the clinic.

Advances in Universal CAR-T Cell Therapy

Chimeric antigen receptor T (CAR-T) cell therapy achieved extraordinary achievements results in antitumor treatments, especially against hematological malignancies, where it leads to remarkable, long-term antineoplastic effects with higher target specificity. Nevertheless, some limitations persist in autologous CAR-T cell therapy, such as high costs, long manufacturing periods, and restricted cell sources. The development of a universal CAR-T (UCAR-T) cell therapy is an attractive breakthrough point that may overcome most of these drawbacks. Here, we review the progress and challenges in CAR-T cell therapy, especially focusing on comprehensive comparison in UCAR-T cell therapy to original CAR-T cell therapy. Furthermore, we summarize the developments and concerns about the safety and efficiency of UCAR-T cell therapy. Finally, we address other immune cells, which might be promising candidates as a complement for UCAR-T cells. Through a detailed overview, we describe the current landscape and explore the prospect of UCAR-T cell therapy.

From Hematopoietic Stem Cell Transplantation to Chimeric Antigen Receptor Therapy: Advances, Limitations and Future Perspectives

Chimeric antigen receptor (CAR) T-cell therapy was envisioned as a mechanism to re-direct effector T-cells to eliminate tumor cells. CARs are composed of the variable region of an antibody that binds a native cancer antigen coupled to the signaling domain of a TCR and co-stimulatory molecules. Its success and approval by the U.S. Food and Drug Administration for the treatment of B-cell malignancies revolutionized the immunotherapy field, leading to extensive research on its possible application for other cancer types. In this review, we will focus on the evolution of CAR-T cell therapy outlining current technologies as well as major obstacles for its wide application. We will highlight achievements, the efforts to increase efficacy and to evolve into an off-the-shelf treatment, and as a possible future treatment for non-cancer related diseases.

Promise and pitfalls of allogeneic chimeric antigen receptor therapy in plasma cell and lymphoid malignancies

Chimeric antigen receptor (CAR) T-cell therapy is a promising immunotherapy in haematological malignancies. However, the currently approved products are generated from autologous T cells that require orchestration of several logistically complex steps, which include patient eligibility, apheresis capability, complex manufacturing processes and shipping logistics. Use of third-party donor-derived (allogeneic) effector cells that allows the generation of 'off-the-shelf" CAR T cells (allo-CAR) could circumvent many of the problems associated with autologous CAR T-cell therapy. Several allogeneic products are entering clinical trials, and though early, the results look promising. The recognised potential benefits of allo-CAR do not come without significant challenges, that must be overcome for their widespread use. Alloreactivity, i.e. graft-versus-host disease (GVHD), and rejection of donor T cells is one of the major barriers, while other potential barriers include immunogenicity, unknown in vivo persistence, and CAR T-cell yield. In the present review, we provide a comprehensive review of the challenges associated with autologous CAR, the benefits and potential challenges associated with allo-CAR. Finally, we review the available platforms for allo-CAR for B-cell and plasma cell malignancies.

Choosing the Right Tool for Genetic Engineering: Clinical Lessons from Chimeric Antigen Receptor-T Cells

T cell modification with genes that encode chimeric antigen receptors (CAR-T cells) has shown tremendous promise for the treatment of B cell malignancies. The successful translation of CAR-T cell therapy to other tumor types, including solid tumors, is the next big challenge. As the field advances from second- to next-generation CAR-T cells comprising multiple genetic modifications, more sophisticated methods and tools to engineer T cells are being developed. Viral vectors, especially γ-retroviruses and lentiviruses, are traditionally used for CAR-T cell engineering due to their high transduction efficiency. However, limited genetic cargo, high costs of production under good manufacturing practice (GMP) conditions, and the high regulatory demands are obstacles for widespread clinical translation. To overcome these limitations, different nonviral approaches are being explored at a preclinical or clinical level, including transposon/transposase systems and mRNA electroporation and nonintegrating DNA nanovectors. Genome editing tools that allow efficient knockout of particular genes and/or site-directed integration of the CAR and/or other transgenes into the genome are also being evaluated for CAR-T cell engineering. In this review, we discuss the development of viral and nonviral vectors used to generate CAR-T cells, focusing on their advantages and limitations. We also discuss the lessons learned from clinical trials using the different genetic engineering tools, with special focus on safety and efficacy.

Cellular Therapy Updates in B-Cell Lymphoma: The State of the CAR-T

Simple Summary

B-cell lymphomas are the most commonly occurring blood cancer and the second leading cause of cancer-related death among blood cancers. Chemotherapy and stem cell transplantation have long served as the standard therapies for relapsed or refractory aggressive B-cell lymphomas with very poor survival, historically. Recently, the development of multiple chimeric antigen receptor T-cell (CAR-T) products has translated into dramatically improved outcomes and survival for patients with relapsed or refractory B-cell lymphoma. Meanwhile, basic, translational and clinical development within the field has progressed rapidly. The aim of this review is to summarize the current state of the art of CAR-T therapies for B-cell lymphomas within this rapidly evolving field, focusing on current United States Food and Drug Administration (US FDA)-approved products and a selection of promising areas of future clinical development.

Abstract

Non-Hodgkin Lymphoma accounts for >460,000 cases and >240,000 deaths globally and >77,000 cases and >20,000 deaths in the U.S. annually, with ~85% of cases being B-cell malignancies. Until recently, patients with relapsed/refractory B-cell lymphoma following standard chemotherapy in combination with anti-CD20 monoclonal antibodies and autologous stem cell transplantation experienced a median overall survival (OS) of <6 months. However, with the approval of four different CD-19 CAR-T therapies between 2017 and 2021, approximately 60–80% of patients receiving CAR-T therapy now achieve an objective response with >3 years median OS. Here, we review the current state of the art of CD19 CAR-T therapies for B-cell lymphomas, focusing on current updates in US FDA-approved products, along with their associated efficacy and toxicities. Lastly, we highlight a selection of promising clinical developments in the field, including various novel strategies to increase CAR-T therapy efficacy while mitigating toxicity.

Challenges and Prospects for Designer T and NK Cells in Glioblastoma Immunotherapy

Glioblastoma (GBM) is the most prevalent, aggressive primary brain tumour with a dismal prognosis. Treatment at diagnosis has limited efficacy and there is no standardised treatment at recurrence. New, personalised treatment options are under investigation, although challenges persist for heterogenous tumours such as GBM. Gene editing technologies are a game changer, enabling design of novel molecular-immunological treatments to be used in combination with chemoradiation, to achieve long lasting survival benefits for patients. Here, we review the literature on how cutting-edge molecular gene editing technologies can be applied to known and emerging tumour-associated antigens to enhance chimeric antigen receptor T and NK cell therapies for GBM. A tight balance of limiting neurotoxicity, avoiding tumour antigen loss and therapy resistance, while simultaneously promoting long-term persistence of the adoptively transferred cells must be maintained to significantly improve patient survival. We discuss the opportunities and challenges posed by the brain contexture to the administration of the treatments and achieving sustained clinical responses.

Mutant B2M-HLA-E and B2M-HLA-G fusion proteins protects universal chimeric antigen receptor-modified T cells from allogeneic NK cell-mediated lysis

Recent studies have indicated the antitumor activity and reduced allogeneic response of universal chimeric antigen receptor-modified T (UCAR T) cells lacking endogenous T cell receptors and beta-2 microglobulin (B2M) generated using gene-editing technologies. However, these cells are vulnerable to lysis by allogeneic natural killer (NK) cells due to their lack of human leukocyte antigen (HLA) class I molecule expression. Here, constitutive expression of mutant B2M-HLA-E (mBE) and B2M-HLA-G (mBG) fusion proteins in anti-CD19 UCAR T (UCAR T-19) cells was conducted to protect against allogeneic NK cell-mediated lysis. The ability of cells expressing mBE or mBG to resist NK cell-mediated lysis was observed in gene-edited Jurkat CAR19 cells. UCAR T-19 cells constitutively expressing the mBE and mBG fusion proteins were manufactured and showed effective and specific anti-tumor activity. Constitutive expression of the mBE and mBG fusion proteins in UCAR T-19 cells prevented allogeneic NK cell-mediated lysis. In addition, these cells were not recognizable by allogeneic T cells. Additional experiments, including those in animal models and clinical trials, are required to evaluate the safety and efficacy of UCAR T-19 cells that constitutively express mBE and mBG.

Advances in Adoptive Cell Therapy Using Induced Pluripotent Stem Cell-Derived T Cells

Adoptive cell therapy (ACT) using chimeric antigen receptor (CAR) T cells holds impressive clinical outcomes especially in patients who are refractory to other kinds of therapy. However, many challenges hinder its clinical applications. For example, patients who undergo chemotherapy usually have an insufficient number of autologous T cells due to lymphopenia. Long-term ex vivo expansion can result in T cell exhaustion, which reduces the effector function. There is also a batch-to-batch variation during the manufacturing process, making it difficult to standardize and validate the cell products. In addition, the process is labor-intensive and costly. Generation of universal off-the-shelf CAR T cells, which can be broadly given to any patient, prepared in advance and ready to use, would be ideal and more cost-effective. Human induced pluripotent stem cells (iPSCs) provide a renewable source of cells that can be genetically engineered and differentiated into immune cells with enhanced anti-tumor cytotoxicity. This review describes basic knowledge of T cell biology, applications in ACT, the use of iPSCs as a new source of T cells and current differentiation strategies used to generate T cells as well as recent advances in genome engineering to produce next-generation off-the-shelf T cells with improved effector functions. We also discuss challenges in the field and future perspectives toward the final universal off-the-shelf immunotherapeutic products.

Scalable Manufacturing of CAR T cells for Cancer Immunotherapy

As of April 2021, there are five commercially available chimeric antigen receptor (CAR) T cell therapies for hematological malignancies. With the current transition of CAR T cell manufacturing from academia to industry, there is a shift toward Good Manufacturing Practice (GMP)-compliant closed and automated systems to ensure reproducibility and to meet the increased demand for cancer patients. In this review we describe current CAR T cells clinical manufacturing models and discuss emerging technological advances that embrace scaling and production optimization. We summarize measures being used to shorten CAR T-cell manufacturing times and highlight regulatory challenges to scaling production for clinical use.

Statement of Significance ∣

As the demand for CAR T cell cancer therapy increases, several closed and automated production platforms are being deployed, and others are in development.This review provides a critical appraisal of these technologies that can be leveraged to scale and optimize the production of next generation CAR T cells.

Combination strategies to maximize the benefits of cancer immunotherapy

Immunotherapies such as immune checkpoint blockade (ICB) and adoptive cell therapy (ACT) have revolutionized cancer treatment, especially in patients whose disease was otherwise considered incurable. However, primary and secondary resistance to single agent immunotherapy often results in treatment failure, and only a minority of patients experience long-term benefits. This review article will discuss the relationship between cancer immune response and mechanisms of resistance to immunotherapy. It will also provide a comprehensive review on the latest clinical status of combination therapies (e.g., immunotherapy with chemotherapy, radiation therapy and targeted therapy), and discuss combination therapies approved by the US Food and Drug Administration. It will provide an overview of therapies targeting cytokines and other soluble immunoregulatory factors, ACT, virotherapy, innate immune modifiers and cancer vaccines, as well as combination therapies that exploit alternative immune targets and other therapeutic modalities. Finally, this review will include the stimulating insights from the 2020 China Immuno-Oncology Workshop co-organized by the Chinese American Hematologist and Oncologist Network (CAHON), the China National Medical Product Administration (NMPA) and Tsinghua University School of Medicine.

Optimized two-step electroporation process to achieve efficient nonviral-mediated gene insertion into primary T cells

The development of gene editing technologies over the past years has allowed the precise and efficient insertion of transgenes into the genome of various cell types. Knock‐in approaches using homology‐directed repair and designer nucleases often rely on viral vectors, which can considerably impact the manufacturing cost and timeline of gene‐edited therapeutic products. An attractive alternative would be to use naked DNA as a repair template. However, such a strategy faces challenges such as cytotoxicity from double‐stranded DNA (dsDNA) to primary cells. Here, we sought to study the kinetics of transcription activator‐like effector nuclease (TALEN)‐mediated gene editing in primary T cells to improve nonviral gene knock‐in. Harnessing this knowledge, we developed a rapid and efficient gene insertion strategy based on either short single‐stranded oligonucleotides or large (2 Kb) linear naked dsDNA sequences. We demonstrated that a time‐controlled two‐step transfection protocol can substantially improve the efficiency of nonviral transgene integration in primary T cells. Using this approach, we achieved modification of up to ˜ 30% of T cells when inserting a chimeric antigen receptor (CAR) at the T‐cell receptor alpha constant region (TRAC) locus to generate ‘off‐the shelf’ CAR‐T cells.

Genetical engineering for NK and T cell immunotherapy with CRISPR/Cas9 technology: Implications and challenges

Immunotherapy has become one of the most promising strategies in cancer therapies. Among the therapeutic alternatives, genetically engineered NK/T cell therapies have emerged as powerful and innovative therapeutic modalities for cancer patients with precise targeting and impressive efficacy. Nonetheless, this approach still faces multiple challenges, such as immunosuppressive tumor microenvironment, exhaustion of immune effector cells in tumors, off-target effects manufacturing complexity, and poor infiltration of effector cells, all of which need to be overcome for further utilization to cancers. Recently, CRISPR/Cas9 genome editing technology, with the goal of enhancing the efficacy and increasing the availability of engineered effector cell therapies, has shown considerable potential in the novel strategies and options to overcome these limitations. Here we review the current progress of the applications of CRISPR in cancer immunotherapy. Furthermore, we discuss issues related to the NK/T cell applications, gene delivery methods, efficiency, challenges, and implications of CRISPR/Cas9.

BCMA in Multiple Myeloma-A Promising Key to Therapy

Despite the discoveries of numerous agents including next generation proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies, multiple myeloma (MM) remains an incurable disease. The field of myeloma treatment in refractory or relapsed patients after standard therapy entered a new era due to the B-cell maturation antigen (BMCA) targeted approach. BCMA is a member of the tumor necrosis factor receptor family with high expression in mature B-lymphocytes and plasma cells. Given the understanding of BCMA mechanism of action in MM, BCMA plays a promising role as a therapeutic target. Several clinical trials are underway to evolve the current BCMA targeted treatment concept such as antibody-drug conjugates (ADCs), bispecific T cell engagers (BITEs) and chimeric antigen receptor (CAR) T cell therapy. Current results of representative BCMA trials may close the gap of the unmet clinical need to further improve the outcome of heavily pretreated MM patients with the potency to change the paradigm in newly diagnosed and refractory MM. This comprehensive review will give an update on various BMCA targeted treatment modalities (ADCs, BITEs, CAR T cell therapy) and its existing results on efficacy and safety from preclinical and clinical trials.

Recent Progress in Genome Editing for Gene Therapy Applications: The French Perspective

Recent advances in genome editing tools, especially novel developments in the clustered regularly interspaced short palindromic repeats associated to Cas9 nucleases (CRISPR/Cas9)-derived editing machinery, have revolutionized not only basic science but, importantly, also the gene therapy field. Their flexibility and ability to introduce precise modifications in the genome to disrupt or correct genes or insert expression cassettes in safe harbors in the genome underline their potential applications as a medicine of the future to cure many genetic diseases. In this review, we give an overview of the recent progress made by French researchers in the field of therapeutic genome editing, while putting their work in the general context of advances made in the field. We focus on recent hematopoietic stem cell gene editing strategies for blood diseases affecting the red blood cells or blood coagulation as well as lysosomal storage diseases. We report on a genome editing-based therapy for muscular dystrophy and the potency of T cell gene editing to increase anticancer activity of chimeric antigen receptor T cells to combat cancer. We will also discuss technical obstacles and side effects such as unwanted editing activity that need to be surmounted on the way toward a clinical implementation of genome editing. We propose here improvements developed today, including by French researchers to overcome the editing-related genotoxicity and improve editing precision by the use of novel recombinant nuclease-based systems such as nickases, base editors, and prime editors. Finally, a solution is proposed to resolve the cellular toxicity induced by the systems employed for gene editing machinery delivery.

Molecular Markers and Targets in Melanoma

Melanoma develops as a result of several genetic alterations, with UV radiation often acting as a mutagenic risk factor. Deep knowledge of the molecular signaling pathways of different types of melanoma allows better characterization and provides tools for the development of therapies based on the intervention of signals promoted by these cascades. The latest World Health Organization classification acknowledged the specific genetic drivers leading to melanoma and classifies melanocytic lesions into nine distinct categories according to the associate cumulative sun damage (CSD), which correlates with the molecular alterations of tumors. The largest groups are melanomas associated with low-CSD or superficial spreading melanomas, characterized by frequent presentation of the BRAFV600 mutation. High-CSD melanomas include lentigo maligna type and desmoplastic melanomas, which often have a high mutation burden and can harbor NRAS, BRAFnon-V600E, or NF1 mutations. Non-CSD-associated melanomas encompass acral and mucosal melanomas that usually do not show BRAF, NRAS, or NF1 mutations (triple wild-type), but in a subset may have KIT or SF3B1 mutations. To improve survival, these driver alterations can be treated with targeted therapy achieving significant antitumor activity. In recent years, relevant improvement in the prognosis and survival of patients with melanoma has been achieved, since the introduction of BRAF/MEK tyrosine kinase inhibitors and immune checkpoint inhibitors. In this review, we describe the current knowledge of molecular pathways and discuss current and potential therapeutic targets in melanoma, focusing on their clinical relevance of development.

Genome Editing in Medicine: Tools and Challenges

Studies which seek fundamental, thorough knowledge of biological processes, and continuous advancement in natural sciences and biotechnology enable the establishment of molecular strategies and tools to treat disorders caused by genetic mutations. Over the years biological therapy evolved from using stem cells and viral vectors to RNA therapy and testing different genome editing tools as promising gene therapy agents. These genome editing technologies (Zinc finger nucleases, TAL effector nucleases), specifically CRISPR-Cas system, revolutionized the field of genetic engineering and is widely applied to create cell and animal models for various hereditary, infectious human diseases and cancer, to analyze and understand the molecular and cellular base of pathogenesis, to find potential drug/treatment targets, to eliminate pathogenic DNA changes in various medical conditions and to create future “precise medication”. Although different concerning factors, such as precise system delivery to the target cells, efficacy and accuracy of editing process, different approaches of making the DNA changes as well as worrying bioethical issues remain, the importance of genome editing technologies in medicine is undeniable. The future of innovative genome editing approach and strategies to treat diseases is complicated but interesting and exciting at once for all related parties – researchers, clinicians, and patients.

Phase I study of CAR-T cells with PD-1 and TCR disruption in mesothelin-positive solid tumors

Programmed cell death protein-1 (PD-1)-mediated immunosuppression has been proposed to contribute to the limited clinical efficacy of chimeric antigen receptor T (CAR-T) cells in solid tumors. We generated PD-1 and T cell receptor (TCR) deficient mesothelin-specific CAR-T (MPTK-CAR-T) cells using CRISPR-Cas9 technology and evaluated them in a dose-escalation study. A total of 15 patients received one or more infusions of MPTK-CAR-T cells without prior lymphodepletion. No dose-limiting toxicity or unexpected adverse events were observed in any of the 15 patients. The best overall response was stable disease (2/15 patients). Circulating MPTK-CAR-T cells peaked at days 7–14 and became undetectable beyond 1 month. TCR-positive CAR-T cells rather than TCR-negative CAR-T cells were predominantly detected in effusion or peripheral blood from three patients after infusion. We further confirmed the reduced persistence of TCR-deficient CAR-T cells in animal models. Our results establish the preliminary feasibility and safety of CRISPR-engineered CAR-T cells with PD-1 disruption and suggest that the natural TCR plays an important role in the persistence of CAR-T cells when treating solid tumors.

A deep insight into CRISPR/Cas9 application in CAR-T cell-based tumor immunotherapies

To date, two chimeric antigen receptors (CAR)-T cell products from autologous T cells have been approved by The United States Food and Drug Administration (FDA). The case-by-case autologous T cell generation setting is largely considered as a pivotal restraining cause for its large-scale clinical use because of the costly and prolonged manufacturing procedure. Further, activated CAR-T cells mainly express immune checkpoint molecules, including CTLA4, PD1, LAG3, abrogating CAR-T anti-tumor activity. In addition, CAR-T cell therapy potently results in some toxicity, such as cytokine releases syndrome (CRS). Therefore, the development of the universal allogeneic T cells with higher anti-tumor effects is of paramount importance. Thus, genome-editing technologies, in particular, clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 are currently being used to establish "off-the-shelf" CAR-T cells with robust resistance to immune cell-suppressive molecules. In fact, that simultaneous ablation of PD-1, T cell receptor alpha constant (TRAC or TCR), and also β-2 microglobulin (B2M) by CRISPR-Cas9 technique can support the manufacture of universal CAR-T cells with robust resistance to PD-L1. . Indeed, the ablation of β2M or TARC can severely hinder swift elimination of allogeneic T cells those express foreign HLA-I molecules, and thereby enables the generation of CAR-T cells from allogeneic healthy donors T cells with higher persistence in vivo. Herein, we will deliver a brief overview of the CAR-T cell application in the context of tumor immunotherapy. More importantly, we will discuss recent finding concerning the application of genome editing technologies for preparing universal CAR-T cells or cells that can effectively counter tumor escape, with a special focus on CRISPR-Cas9 technology.

CRISPR/Cas9 technology: towards a new generation of improved CAR-T cells for anticancer therapies

Chimeric antigen receptor (CAR)-modified T cells have raised among other immunotherapies for cancer treatment, being implemented against B-cell malignancies. Despite the promising outcomes of this innovative technology, CAR-T cells are not exempt from limitations that must yet to be overcome in order to provide reliable and more efficient treatments against other types of cancer. The purpose of this review is to shed light on the field of CAR-T cell gene editing for therapy universalization and further enhancement of antitumor function. Several studies have proven that the disruption of certain key genes is essential to boost immunosuppressive resistance, prevention of fratricide, and clinical safety. Due to its unparalleled simplicity, feasibility to edit multiple gene targets simultaneously, and affordability, CRISPR/CRISPR-associated protein 9 system has been proposed in different clinical trials for such CAR-T cell improvement. The combination of such powerful technologies is expected to provide a new generation of CAR-T cell-based immunotherapies for clinical application.

Applications and explorations of CRISPR/Cas9 in CAR T-cell therapy

Chimeric antigen receptor(CAR) T-cell therapy has shown remarkable effects and promising prospects in patients with refractory or relapsed malignancies, pending further progress in the next-generation CAR T cells with more optimized structure, enhanced efficacy and reduced toxicities. The clustered regulatory interspaced short palindromic repeat/CRISPR-associated protein 9 (CRISPR/Cas9) technology holds immense promise for advancing the field owing to its flexibility, simplicity, high efficiency and multiplexing in precise genome editing. Herein, we review the applications and explorations of CRISPR/Cas9 technology in constructing allogenic universal CAR T cells, disrupting inhibitory signaling to enhance potency and exploration of safer and more controllable novel CAR T cells.

Combination of CRISPR/Cas9 System and CAR-T Cell Therapy: A New Era for Refractory and Relapsed Hematological Malignancies

Chimeric antigen receptor T (CAR-T) cell therapy is the novel treatment strategy for hematological malignancies such as acute lymphoblastic leukemia (ALL), lymphoma and multiple myeloma. However, treatment-related toxicities such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) have become significant hurdles to CAR-T treatment. Multiple strategies were established to alter the CAR structure on the genomic level to improve efficacy and reduce toxicities. Recently, the innovative gene-editing technology-clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease9 (Cas9) system, which particularly exhibits preponderance in knock-in and knockout at specific sites, is widely utilized to manufacture CAR-T products. The application of CRISPR/Cas9 to CAR-T cell therapy has shown promising clinical results with minimal toxicity. In this review, we summarized the past achievements of CRISPR/Cas9 in CAR-T therapy and focused on the potential CAR-T targets.

Genome engineering and disease modeling via programmable nucleases for insulin gene therapy; promises of CRISPR/Cas9 technology

Targeted genome editing is a continually evolving technology employing programmable nucleases to specifically change, insert, or remove a genomic sequence of interest. These advanced molecular tools include meganucleases, zinc finger nucleases, transcription activator-like effector nucleases and RNA-guided engineered nucleases (RGENs), which create double-strand breaks at specific target sites in the genome, and repair DNA either by homologous recombination in the presence of donor DNA or via the error-prone non-homologous end-joining mechanism. A recently discovered group of RGENs known as CRISPR/Cas9 gene-editing systems allowed precise genome manipulation revealing a causal association between disease genotype and phenotype, without the need for the reengineering of the specific enzyme when targeting different sequences. CRISPR/Cas9 has been successfully employed as an ex vivo gene-editing tool in embryonic stem cells and patient-derived stem cells to understand pancreatic beta-cell development and function. RNA-guided nucleases also open the way for the generation of novel animal models for diabetes and allow testing the efficiency of various therapeutic approaches in diabetes, as summarized and exemplified in this manuscript.

A Deep Insight Into CAR-T Cell Therapy in Non-Hodgkin Lymphoma: Application, Opportunities, and Future Directions

Non-Hodgkin's lymphoma (NHL) is a cancer that starts in the lymphatic system. In NHL, the important part of the immune system, a type of white blood cells called lymphocytes become cancerous. NHL subtypes include marginal zone lymphoma, small lymphocytic lymphoma, follicular lymphoma (FL), and lymphoplasmacytic lymphoma. The disease can emerge in either aggressive or indolent form. 5-year survival duration after diagnosis is poor among patients with aggressive/relapsing form of NHL. Therefore, it is necessary to understand the molecular mechanisms of pathogenesis involved in NHL establishment and progression. In the next step, we can develop innovative therapies for NHL based on our knowledge in signaling pathways, surface antigens, and tumor milieu of NHL. In the recent few decades, several treatment solutions of NHL mainly based on targeted/directed therapies have been evaluated. These approaches include B-cell receptor (BCR) signaling inhibitors, immunomodulatory agents, monoclonal antibodies (mAbs), epigenetic modulators, Bcl-2 inhibitors, checkpoint inhibitors, and T-cell therapy. In recent years, methods based on T cell immunotherapy have been considered as a novel promising anti-cancer strategy in the treatment of various types of cancers, and particularly in blood cancers. These methods could significantly increase the capacity of the immune system to induce durable anti-cancer responses in patients with chemotherapy-resistant lymphoma. One of the promising therapy methods involved in the triumph of immunotherapy is the chimeric antigen receptor (CAR) T cells with dramatically improved killing activity against tumor cells. The CAR-T cell-based anti-cancer therapy targeting a pan-B-cell marker, CD19 is recently approved by the US Food and Drug Administration (FDA) for the treatment of chemotherapy-resistant B-cell NHL. In this review, we will discuss the structure, molecular mechanisms, results of clinical trials, and the toxicity of CAR-T cell-based therapies. Also, we will criticize the clinical aspects, the treatment considerations, and the challenges and possible drawbacks of the application of CAR-T cells in the treatment of NHL.

Therapeutic Gene Editing with CRISPR: A Laboratory Medicine Perspective

Therapeutic gene editing with the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas system offers significant improvements in specificity and programmability compared with previous methods. CRISPR editing strategies can be used ex vivo and in vivo with many theoretic disease applications. Off-target effects of CRISPR-mediated gene editing are an important outcome to be aware of, minimize, and detect. The current methods of regulatory approval for personalized therapies are complex and may be proved inefficient as these therapies are implemented more widely. The role of pathologists and laboratory medicine practitioners is vital to the clinical implementation of therapeutic gene editing.

CD38-specific Chimeric Antigen Receptor Expressing Natural Killer KHYG-1 Cells: A Proof of Concept for an "Off the Shelf" Therapy for Multiple Myeloma

Chimeric antigen receptor (CAR) T cells are highly successful in the treatment of hematologic malignancies. We recently generated affinity-optimized CD38CAR T cells, which effectively eliminate multiple myeloma (MM) cells with little or no toxicities against nonmalignant hematopoietic cells. The lack of universal donors and long manufacturing times however limit the broad application of CAR T cell therapies. Natural killer (NK) cells generated from third party individuals may represent a viable source of "off the shelf" CAR-based products, as they are not associated with graft-versus-host disease unlike allogeneic T cells. We therefore explored the preclinical anti-MM efficacy and potential toxicity of the CD38CAR NK concept by expressing affinity-optimized CD38CARs in KHYG-1 cells, an immortal NK cell line with excellent expansion properties. KHYG-1 cells retrovirally transduced with the affinity-optimized CD38CARs expanded vigorously and mediated effective CD38-dependent cytotoxicity towards CD38^high MM cell lines as well as primary MM cells ex vivo. Importantly, the intermediate affinity CD38CAR transduced KHYG-1 cells spared CD38^neg or CD38^int nonmalignant hematopoietic cells, indicating an optimal tumor nontumor discrimination. Irradiated, short living CD38CAR KHYG-1 cells also showed significant anti-MM effects in a xenograft model with a humanized bone marrow-like niche. Finally, CD38CAR KHYG-1 cells effectively eliminated primary MM cells derived from patients who are refractory to CD38 antibody daratumumab. Taken together, the results of this proof-of-principle study demonstrate the potential value of engineering affinity-optimized CD38CARs in NK cells to establish effective anti-MM effects, with an excellent safety profile, even in patients who failed to response to most advanced registered myeloma therapies, such as daratumumab.

Avoiding Stops and Overcoming Roadblocks: Considerations for Improving Patient Access to CAR-Based Cell Therapies

Adoptive cell therapy has significantly impacted the immuno-oncology landscape. The number of strategies currently in preclinical and clinical development is increasing at a rapid rate. Indeed, we are experiencing a transformative movement in cancer care as we shift toward highly personalized treatments designed to confront the specific challenges of each cancer. Advancements in genetic engineering methods and single-cell profiling technologies provide a level of understanding of the interactions between the immune system and cancer never before achieved. This knowledge, in turn, can be applied to the design and engineering of effective cancer-fighting treatments. As these promising new therapies progress toward clinical application, it becomes evident that we must develop robust methods for production and validation of cellular products to ensure consistency, safety, and efficacy, irrespective of cell type or indication. Herein, we provide an overview of the innovative approaches guiding the new generation of cell therapies and describe the benefits and challenges associated with emerging autologous and allogeneic platforms. Moreover, we discuss important considerations pertaining to process development, cost of goods, and manufacturing, and highlight their impact on the transfer of therapies from bench to bedside.

Approaches for refining and furthering the development of CAR-based T cell therapies for solid malignancies

Introduction: Chimeric antigen receptor-engineered T-cells typically use the binding domains of antibodies to target cytotoxicity toward tumors. This approach has produced great efficacy against selected hematological cancers, but benefit in solid tumors has been limited. Characteristically, the microenvironment in solid tumors restricts CAR T cell function, thereby limiting success. Enhancing efficacy will depend on novel target discovery to refine specificity and reduce toxicity. Additionally, overcoming immunosuppressive mechanisms may be achieved by altering the structure of the CAR itself, together with ancillary gene expression or additional therapeutic interventions.Areas covered: Herein, the authors discuss approaches for refining and further developing CAR T cell therapies specifically for use with solid malignancies. The authors survey the existing literature and provide perspectives for the future.Expert opinion: Pronounced efficacy in solid tumors will likely require combination therapies, targeting both the tumor itself and associated immunosuppressive mechanisms. Future exploration of CAR T cell therapies for solid tumors is likely to incorporate next-generation designs that couple more precise targeting of cancer-associated targets with enhanced potency and resistance to exhaustion.

Graft-versus-host disease risk after chimeric antigen receptor T-cell therapy: the diametric opposition of T cells

Chimeric antigen receptor (CAR) T-cell therapy has brought a paradigm shift in the management of haematological malignancies and has opened novel avenues of investigational therapeutic strategies. Given these encouraging responses, it has become imperative to understand the full spectrum of biology and potential toxicities that can arise from these novel agents, as well as those under investigation. With the increasing use of CAR T-cell therapy for relapse following allogeneic haematopoietic cell transplantation (HCT) and the imminence of allogeneic CAR T cells, risks from T cell-based therapy, such as the previously well-recognised graft-versus-host disease (GVHD), have gained prominence and warrant explanation. In the present review, we discuss the risk of GVHD in the: (1) post-HCT setting using recipient or donor-derived CAR T cells, as well as (2) non-HCT setting using autologous, as well as allogeneic T-cell therapies. A better understanding of this risk is important to advance the field and ensure safe development and use of these agents in the clinic.

CRISPR/Cas9 Gene-Editing in Cancer Immunotherapy: Promoting the Present Revolution in Cancer Therapy and Exploring More

In recent years, immunotherapy has showed fantastic promise in pioneering and accelerating the field of cancer therapy and embraces unprecedented breakthroughs in clinical practice. The clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein 9 (CRISPR-Cas9) system, as a versatile gene-editing technology, lays a robust foundation to efficiently innovate cancer research and cancer therapy. Here, we summarize recent approaches based on CRISPR/Cas9 system for construction of chimeric antigen receptor T (CAR-T) cells and T cell receptor T (TCR-T) cells. Besides, we review the applications of CRISPR/Cas9 in inhibiting immune checkpoint signaling pathways and highlight the feasibility of CRISPR/Cas9 based engineering strategies to screen novel cancer immunotherapy targets. Conclusively, we discuss the perspectives, potential challenges and possible solutions in this vivid growing field.

How Can We Engineer CAR T Cells to Overcome Resistance?

Chimeric antigen receptor (CAR) T cell therapy has achieved unrivalled success in the treatment of B cell and plasma cell malignancies, with five CAR T cell products now approved by the US Food and Drug Administration (FDA). However, CAR T cell therapies for solid tumours have not been nearly as successful, owing to several additional challenges. Here, we discuss mechanisms of tumour resistance in CAR T cell therapy and the emerging strategies that are under development to engineer CAR T cells to overcome resistance.

Cell therapy in transplantation: A comprehensive review of the current applications of cell therapy in transplant patients with the focus on Tregs, CAR Tregs, and Mesenchymal stem cells

Organ transplantation is a practical treatment for patients with end-stage organ failure. Despite the advances in short-term graft survival, long-term graft survival remains the main challenge considering the increased mortality and morbidity associated with chronic rejection and the toxicity of immunosuppressive drugs. Since a novel therapeutic strategy to induce allograft tolerance seems urgent, focusing on developing novel and safe approaches to prolong graft survival is one of the main goals of transplant investigators. Researchers in the field of organ transplantation are interested in suppressing or optimizing the immune responses by focusing on immune cells including mesenchymal stem cells (MSCs), polyclonal regulatory Tcells (Tregs), and antigen-specific Tregs engineered with chimeric antigen receptors (CAR Tregs). We review the mechanistic pathways, phenotypic and functional characteristics of these cells, and their promising application in organ transplantation.

[Chimeric antigen receptors (CARs): universal tools in adoptive cell therapy]

BACKGROUND

The observation that tumor-infiltrating lymphocytes (TIL) after ex vivo amplification can control tumors in the long term led to the concept of redirecting patients' cytolytic T‑cells by a receptor with defined specificity against the tumor.

OBJECTIVES

Development of a recombinant receptor-signal molecule (chimeric antigen receptor, CAR) to increase selectivity and enhance anti-tumor immunity.

METHODS

Description of a prototype CAR, overview of the modular composition and further development of CAR technology for use in adoptive immune cell therapy.

RESULTS

Intensive research over the last two decades has shown how CAR-mediated T‑cell activation is influenced by factors such as binding affinity, the epitope of the target antigen, its expression density and accessibility on the tumor cells, as well as by the signaling domains and their combination to induce T‑cell activation. The quality and duration of the T‑cell response can be specifically modulated by modifying the modular composition of the CAR; CAR T‑cells can act as "biopharmaceutical factories" (T-cells redirected for unrestricted cytokine-mediated killing, TRUCK) in the tissue by CAR-mediated release of transgenic therapeutic proteins.

CONCLUSION

Adoptive CAR T‑cell therapy has shown clinical efficacy in the treatment of hematological malignancies; the treatment of solid tumors, however, is more challenging. Allogeneic CAR T‑cell technology is aimed at generating "off-the-shelf" CAR T‑cells that are accessible for a large number of patients. A further promising approach is the use of CAR T‑cells for other therapeutic applications such as the treatment of autoimmune diseases.

Non-viral transfection technologies for next-generation therapeutic T cell engineering

Genetically engineered T cells have sparked interest in advanced cancer treatment, reaching a milestone in 2017 with two FDA-approvals for CD19-directed chimeric antigen receptor (CAR) T cell therapeutics. It is becoming clear that the next generation of CAR T cell therapies will demand more complex engineering strategies and combinations thereof, including the use of revolutionary gene editing approaches. To date, manufacturing of CAR T cells mostly relies on γ-retroviral or lentiviral vectors, but their use is associated with several drawbacks, including safety issues, high manufacturing cost and vector capacity constraints. Non-viral approaches, including membrane permeabilization and carrier-based techniques, have therefore gained a lot of interest to replace viral transductions in the manufacturing of T cell therapeutics. This review provides an in-depth discussion on the avid search for alternatives to viral vectors, discusses key considerations for T cell engineering technologies, and provides an overview of the emerging spectrum of non-viral transfection technologies for T cells. Strengths and weaknesses of each technology will be discussed in relation to T cell engineering. Altogether, this work emphasizes the potential of non-viral transfection approaches to advance the next-generation of genetically engineered T cells.

State-of-Art of Cellular Therapy for Acute Leukemia

With recent clinical breakthroughs, immunotherapy has become the fourth pillar of cancer treatment. Particularly, immune cell-based therapies have been envisioned as a promising treatment option with curative potential for leukemia patients. Hence, an increasing number of preclinical and clinical studies focus on various approaches of immune cell-based therapy for treatment of acute leukemia (AL). However, the use of different immune cell lineages and subsets against different types of leukemia and patient disease statuses challenge the interpretation of the clinical applicability and outcome of immune cell-based therapies. This review aims to provide an overview on recent approaches using various immune cell-based therapies against acute B-, T-, and myeloid leukemias. Further, the apparent limitations observed and potential approaches to overcome these limitations are discussed.

Delivery technologies for T cell gene editing: Applications in cancer immunotherapy

While initial approaches to adoptive T cell therapy relied on the identification and expansion of rare tumour-reactive T cells, genetic engineering has transformed cancer immunotherapy by enabling the modification of primary T cells to increase their therapeutic potential. Specifically, gene editing technologies have been utilized to create T cell populations with improved responses to antigens, lower rates of exhaustion, and potential for use in allogeneic applications. In this review, we provide an overview of T cell therapy gene editing strategies and the delivery technologies utilized to genetically engineer T cells. We also discuss recent investigations and clinical trials that have utilized gene editing to enhance the efficacy of T cells and broaden the application of cancer immunotherapies.

Immunotherapy to get on point with base editing

Engineered immune cell therapy is revolutionising the field of cancer therapeutics. US Food and Drug Administration (FDA) approval of two chimeric antigen receptor (CAR)-T cell products for the treatment of haematological malignancies paved the way for individualised cancer treatment. However, multiple genetic edits will be required to improve the efficacy of CAR-T cell therapies if they are to treat refractory malignancies successfully, particularly solid tumours. Off-target effects of CRISPR-Cas9-mediated multiplex editing are likely to hinder its safety and application in the clinic. Novel base editing technologies offer a promising and safer alternative for simultaneous editing that could enhance allogeneic engineered immunotherapies for targeting solid tumours and other complex human diseases.

CAR-T cells and BiTEs in solid tumors: challenges and perspectives

Chimeric antigen receptor (CAR)-modified T cells and BiTEs are both immunotherapies which redirect T cell specificity against a tumor-specific antigen through the use of antibody fragments. They demonstrated remarkable efficacy in B cell hematologic malignancies, thus paving the way for their development in solid tumors. Nonetheless, the use of such new drugs to treat solid tumors is not straightforward. So far, the results from early phase clinical trials are not as impressive as expected but many improvements are under way. In this review we present an overview of the clinical development of CAR-T cells and BiTEs targeting the main antigens expressed by solid tumors. We emphasize the most frequent hurdles encountered by either CAR-T cells or BiTEs, or both, and summarize the strategies that have been proposed to overcome these obstacles.

Current Perspectives on the Use of off the Shelf CAR-T/NK Cells for the Treatment of Cancer

Simple Summary

CAR T cells are a type of immunotherapy whereby a patient’s own cells are genetically modified to recognise and kill the patient’s own cancer cells. Currently, each patient has CAR T cells made from their own blood cells. This type of therapy has had a big impact on the treatment of blood cancers, however making an individual treatment from each patient is expensive and labour intensive. This review discusses the potential of making CAR T cells more widely available by producing them in large numbers from healthy donors.

Abstract

CAR T cells have revolutionised the treatment of haematological malignancies. Despite this, several obstacles still prohibit their widespread use and efficacy. One of these barriers is the use of autologous T cells as the carrier of the CAR. The individual production of CAR T cells results in large variation in the product, greater wait times for treatment and higher costs. To overcome this several novel approaches have emerged that utilise allogeneic cells, so called “off the shelf” CAR T cells. In this Review, we describe the different approaches that have been used to produce allogeneic CAR T to date, as well as their current pre-clinical and clinical progress.