A novel method to generate T-cell receptor-deficient chimeric antigen receptor T cells

Leveraging CRISPR gene editing technology to optimize the efficacy, safety and accessibility of CAR T-cell therapy

Chimeric Antigen Receptor (CAR)-T-cell therapy has revolutionized cancer immune therapy. However, challenges remain including increasing efficacy, reducing adverse events and increasing accessibility. Use of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology can effectively perform various functions such as precise integration, multi-gene editing, and genome-wide functional regulation. Additionally, CRISPR screening using large-scale guide RNA (gRNA) genetic perturbation provides an unbiased approach to understanding mechanisms underlying anti-cancer efficacy of CAR T-cells. Several emerging CRISPR tools with high specificity, controllability and efficiency are useful to modify CAR T-cells and identify new targets. In this review we summarize potential uses of the CRISPR system to improve results of CAR T-cells therapy including optimizing efficacy and safety and, developing universal CAR T-cells. We discuss challenges facing CRISPR gene editing and propose solutions highlighting future research directions in CAR T-cell therapy.

Allogeneic CAR-T cells for cancer immunotherapy

Autologous chimeric antigen receptor (CAR)-modified T (CAR-T) cell therapy has displayed high efficacy in the treatment of hematological malignancies. Up to now, 11 autologous CAR-T cell products have been approved for the management of malignancies globally. However, the application of autologous CAR-T cell therapy has many individual limitations, long time-consuming, highly cost, and the risk of manufacturing failure. Indeed, some patients would not benefit from autologous CAR-T cell products because of rapid disease progression. Allogeneic CAR-T cells especially universal CAR-T (U-CAR-T) cell therapy are superior to these challenges of autologous CAR-T cells. In this review, we describe basic study and clinical trials of U-CAR-T cell therapeutic methods for malignancies. In addition, we summarize the problems encountered and potential solutions.

Advances in CAR-T-cell therapy in T-cell malignancies

Significant advances have been made in chimeric antigen receptor T (CAR-T)-cell therapy for the treatment of recurrent or refractory B-cell hematologic malignancies. However, CAR-T-cell therapy has not yet achieved comparable success in the management of aggressive T-cell malignancies. This article reviews the challenges of CAR-T-cell therapy in treating T-cell malignancies and summarizes the progress of preclinical and clinical studies in this area. We present an analysis of clinical trials of CAR-T-cell therapies for the treatment of T-cell malignancies grouped by target antigen classification. Moreover, this review focuses on the major challenges encountered by CAR-T-cell therapies, including the nonspecific killing due to T-cell target antigen sharing and contamination with cell products during preparation. This review discusses strategies to overcome these challenges, presenting novel therapeutic approaches that could enhance the efficacy and applicability of CAR-T-cell therapy in the treatment of T-cell malignancies. These ideas and strategies provide important information for future studies to promote the further development and application of CAR-T-cell therapy in this field.

CellShip: An Ambient Temperature Transport and Short-Term Storage Medium for Mammalian Cell Cultures

Cell culture is a critical platform for numerous research and industrial processes. However, methods for transporting cells are largely limited to cryopreservation, which is logistically challenging, requires the use of potentially cytotoxic cryopreservatives, and can result in poor cell recovery. Development of a transport media that can be used at ambient temperatures would alleviate these issues. In this study, we describe a novel transportation medium for mammalian cells. Five commonly used cell lines, (HEK293, CHO, HepG2, K562, and Jurkat) were successfully shipped and stored for a minimum of 72 hours and up to 96 hours at ambient temperature, after which, cells were recovered into standard culture conditions. Viability (%) and cell numbers, were examined, before, following the transport/storage period and following the recovery period. In all experiments, cell numbers returned to pretransport/storage concentration within 24-48 hours recovery. Imaging data indicated that HepG2 cells were fully adherent and had established typical growth morphology following 48 hours recovery, which was not seen in cells recovered from cryopreservation. Following recovery, Jurkat cells that had been subjected to a 96 hours transport/storage period, demonstrated a 1.93-fold increase compared with the starting cell number with >95% cell viability. We conclude that CellShip® may represent a viable method for the transportation of mammalian cells for multiple downstream applications in the Life Sciences research sector.

Chimeric antigen receptor T-cell therapy for T-cell acute lymphoblastic leukemia

Chimeric antigen receptor (CAR) T-cell therapy is a new and effective treatment for patients with hematologic malignancies. Clinical responses to CAR T cells in leukemia, lymphoma, and multiple myeloma have provided strong evidence of the antitumor activity of these cells. In patients with refractory or relapsed B-cell acute lymphoblastic leukemia (ALL), the infusion of autologous anti-CD19 CAR T cells is rapidly gaining standard-of-care status and might eventually be incorporated into frontline treatment. In T-ALL, however, leukemic cells generally lack surface molecules recognized by established CAR, such as CD19 and CD22. Such deficiency is particularly important, as outcome is dismal for patients with T-ALL that is refractory to standard chemotherapy and/or hematopoietic stem cell transplant. Recently, CAR T-cell technologies directed against T-cell malignancies have been developed and are beginning to be tested clinically. The main technical obstacles stem from the fact that malignant and normal T cells share most surface antigens. Therefore, CAR T cells directed against T-ALL targets might be susceptible to self-elimination during manufacturing and/or have suboptimal activity after infusion. Moreover, removing leukemic cells that might be present in the cell source used for CAR T-cell manufacturing might be problematic. Finally, reconstitution of T cells and natural killer cells after CAR T-cell infusion might be impaired. In this article, we discuss potential targets for CAR T-cell therapy of T-ALL with an emphasis on CD7, and review CAR configurations as well as early clinical results.

CAR-T Cell Therapy for T-Cell Malignancies

Chimeric antigen receptor T-cell (CAR-T) therapy has revolutionized the treatment of B-cell lymphoid neoplasia and, in some instances, improved disease outcomes. Thus, six FDA-approved commercial CAR-T cell products that target antigens preferentially expressed on malignant B-cells or plasma cells have been introduced in the therapy of B-cell lymphomas, B-ALLs, and multiple myeloma. These therapeutic successes have triggered the application of CAR-T cell therapy to other hematologic tumors, including T-cell malignancies. However, the success of CAR-T cell therapies in T-cell neoplasms was considerably more limited due to the existence of some limiting factors, such as: 1) the sharing of mutual antigens between normal T-cells and CAR-T cells and malignant cells, determining fratricide events and severe T-cell aplasia; 2) the contamination of CAR-T cells used for CAR transduction with malignant T-cells. Allogeneic CAR-T products can avoid tumor contamination but raise other problems related to immunological incompatibility. In spite of these limitations, there has been significant progress in CD7- and CD5-targeted CAR-T cell therapy of T-cell malignancies in the last few years.

Chimeric antigen receptor T cells march into T cell malignancies

T cell malignancies represent a diverse collection of leukemia/lymphoma conditions in humans arising from aberrant T cells. Such malignancies are often associated with poor clinical prognoses, cancer relapse, as well as progressive resistance to anti-cancer treatments. While chimeric antigen receptor (CAR) T cell immunotherapy has emerged as a revolutionary treatment strategy that is highly effective for treating B cell malignancies, its application as a treatment for T cell malignancies remains to be better explored. Furthermore, the effectiveness of CAR-T treatment in T cell malignancies is significantly influenced by the quality of contamination-free CAR-T cells during the manufacturing process, as well as by multiple characteristics of such malignancies, including the sharing of antigens across normal and malignant T cells, fratricide, and T cell aplasia. In this review, we provide a detailed account of the current developments in the clinical application of CAR-T therapy to treat T cell malignancies, offer strategies for addressing current challenges, and outline a roadmap toward its effective implementation as a broad treatment option for this condition.

Current approaches to develop "off-the-shelf" chimeric antigen receptor (CAR)-T cells for cancer treatment: a systematic review

Chimeric antigen receptor (CAR)-T cell therapy is one of the most promising advances in cancer treatment. It is based on genetically modified T cells to express a CAR, which enables the recognition of the specific tumour antigen of interest. To date, CAR-T cell therapies approved for commercialisation are designed to treat haematological malignancies, showing impressive clinical efficacy in patients with relapsed or refractory advanced-stage tumours. However, since they all use the patient´s own T cells as starting material (i.e. autologous use), they have important limitations, including manufacturing delays, high production costs, difficulties in standardising the preparation process, and production failures due to patient T cell dysfunction. Therefore, many efforts are currently being devoted to contribute to the development of safe and effective therapies for allogeneic use, which should be designed to overcome the most important risks they entail: immune rejection and graft-versus-host disease (GvHD). This systematic review brings together the wide range of different approaches that have been studied to achieve the production of allogeneic CAR-T cell therapies and discuss the advantages and disadvantages of every strategy. The methods were classified in two major categories: those involving extra genetic modifications, in addition to CAR integration, and those relying on the selection of alternative cell sources/subpopulations for allogeneic CAR-T cell production (i.e. γδ T cells, induced pluripotent stem cells (iPSCs), umbilical cord blood T cells, memory T cells subpopulations, virus-specific T cells and cytokine-induced killer cells). We have observed that, although genetic modification of T cells is the most widely used approach, new approaches combining both methods have emerged. However, more preclinical and clinical research is needed to determine the most appropriate strategy to bring this promising antitumour therapy to the clinical setting.

Strategies for overcoming bottlenecks in allogeneic CAR-T cell therapy

Patient-derived autologous chimeric antigen receptor (CAR)-T cell therapy is a revolutionary breakthrough in immunotherapy and has made impressive progress in both preclinical and clinical studies. However, autologous CAR-T cells still have notable drawbacks in clinical manufacture, such as long production time, variable cell potency and possible manufacturing failures. Allogeneic CAR-T cell therapy is significantly superior to autologous CAR-T cell therapy in these aspects. The use of allogeneic CAR-T cell therapy may provide simplified manufacturing process and allow the creation of 'off-the-shelf' products, facilitating the treatments of various types of tumors at less delivery time. Nevertheless, severe graft-versus-host disease (GvHD) or host-mediated allorejection may occur in the allogeneic setting, implying that addressing these two critical issues is urgent for the clinical application of allogeneic CAR-T cell therapy. In this review, we summarize the current approaches to overcome GvHD and host rejection, which empower allogeneic CAR-T cell therapy with a broader future.

Fine-Tuning through Generations: Advances in Structure and Production of CAR-T Therapy

Chimeric antigen receptor (CAR)-T cell therapy is a promising form of immunotherapy that has seen significant advancements in the past few decades. It involves genetically modifying T cells to target cancer cells expressing specific antigens, providing a novel approach to treating various types of cancer. However, the initial success of first-generation CAR-T cells was limited due to inadequate proliferation and undesirable outcomes. Nonetheless, significant progress has been made in CAR-T cell engineering, leading to the development of the latest fifth-generation CAR-T cells that can target multiple antigens and overcome individual limitations. Despite these advancements, some shortcomings prevent the widespread use of CAR-T therapy, including life-threatening toxicities, T-cell exhaustion, and inadequate infiltration for solid tumors. Researchers have made considerable efforts to address these issues by developing new strategies for improving CAR-T cell function and reducing toxicities. This review provides an overview of the path of CAR-T cell development and highlights some of the prominent advances in its structure and manufacturing process, which include the strategies to improve antigen recognition, enhance T-cell activation and persistence, and overcome immune escape. Finally, the review briefly covers other immune cells for cancer therapy and ends with the discussion on the broad prospects of CAR-T in the treatment of various diseases, not just hematological tumors, and the challenges that need to be addressed for the widespread clinical application of CAR-T cell therapies.

Harnessing the Immune System: Current and Emerging Immunotherapy Strategies for Pediatric Acute Lymphoblastic Leukemia

Treatment for relapsed acute lymphoblastic leukemia (ALL) in children and young adults continues to evolve. Despite optimization of cytotoxic chemotherapeutic approaches and risk-adapted therapy, about 12% of pediatric patients still relapse, and survival rates in this population remain poor. Salvage therapy for relapsed patients continues to be challenging as attempts to further intensify chemotherapy have resulted in excessive toxicity without improving outcomes. Immunotherapy has profoundly impacted the landscape of relapsed ALL by harnessing the patient's immune system to target and eliminate leukemia cells. In this review, we provide an overview and summary of immunotherapy agents that have been approved and remain under investigation for children, including blinatumomab, inotuzumab, daratumomab, and chimeric antigen receptor T-cell therapy. We discuss the landmark clinical trials that have revolutionized the field and provide an update on ongoing clinical trials involving these agents for children in the relapsed and upfront setting. The incorporation of these novel immunotherapies into ALL treatment, either as monotherapy or in combination with cytotoxic chemotherapy, has demonstrated promising potential to augment outcomes while decreasing toxicity. However, we also highlight the many challenges we still face and the research critically needed to achieve our goals for cure in children.

Targeted CD7 CAR T-cells for treatment of T-Lymphocyte leukemia and lymphoma and acute myeloid leukemia: recent advances

The high expression of CD7 targets in T-cell acute lymphoblastic leukemia (T-ALL) and T-lymphoma has attracted considerable attention from researchers. However, because CD7 chimeric antigen receptor (CAR) T-cells undergo fratricide, CD7 CAR T-cells develop an exhaustion phenotype that impairs the effect of CAR T-cells. There have been significant breakthroughs in CD7-targeted CAR T-cell therapy in the past few years. The advent of gene editing, protein blockers, and other approaches has effectively overcome the adverse effects of conventional methods of CD7 CAR T-cells. This review, in conjunction with recent advances in the 64th annual meeting of the American Society of Hematology (ASH), provides a summary of the meaningful achievements in CD7 CAR T-cell generations and clinical trials over the last few years.

CAR T cell therapy for T cell leukemia and lymphoma: latest updates from 2022 ASH Annual Meeting

Due to the concern of fratricide, clinical development of CAR T cells for the therapy of T cell malignancies lags behind that for B cell malignancies. Attempts are being made to revise T cell biomarkers so that the re-engineered CAR T cells can target T cell malignancies. CD3 and CD7 are the two pan-T cell surface biomarkers that have been either knocked out or knocked down through genome base- editing technology or by protein expression blockers so that the re-engineered T cells can target T cells without fratricide. We summarized several latest reports on the CAR T cells for the therapy of T cell leukemia /lymphoma from the 2022 ASH Annual Meeting, with latest updates on clinical trials of TvT CAR7, RD-13-01, and CD7 CART.

Genome-edited allogeneic donor "universal" chimeric antigen receptor T cells

αβ T cell receptor (TCRαβ) T cells modified to express chimeric antigen receptors (CAR), are now available as authorized therapies for certain B-cell malignancies. However the process of autologous harvest and generation of patient-specific products is costly, with complex logistics and infrastructure requirements. Premanufactured banks of allogeneic donor-derived CAR T cells could help widen applicability if the challenges of HLA-mismatched T-cell therapy can be addressed. Genome editing is being applied to overcome allogeneic barriers, most notably, by disrupting TCRαβ to prevent graft-versus-host disease, and multiple competing editing technologies, including CRISPR/Cas9 and base editing, have reached clinical phase testing. Improvements in accuracy and efficiency have unlocked applications for a wider range of blood malignancies, with multiplexed editing incorporated to target HLA molecules, shared antigens and checkpoint pathways. Clinical trials will help establish safety profiles and determine the durability of responses as well as the role of consolidation with allogeneic transplantation.

CAR immune cells: design principles, resistance and the next generation

The remarkable clinical activity of chimeric antigen receptor (CAR) therapies in B cell and plasma cell malignancies has validated the use of this therapeutic class for liquid cancers, but resistance and limited access remain as barriers to broader application. Here we review the immunobiology and design principles of current prototype CARs and present emerging platforms that are anticipated to drive future clinical advances. The field is witnessing a rapid expansion of next-generation CAR immune cell technologies designed to enhance efficacy, safety and access. Substantial progress has been made in augmenting immune cell fitness, activating endogenous immunity, arming cells to resist suppression via the tumour microenvironment and developing approaches to modulate antigen density thresholds. Increasingly sophisticated multispecific, logic-gated and regulatable CARs display the potential to overcome resistance and increase safety. Early signs of progress with stealth, virus-free and in vivo gene delivery platforms provide potential paths for reduced costs and increased access of cell therapies in the future. The continuing clinical success of CAR T cells in liquid cancers is driving the development of increasingly sophisticated immune cell therapies that are poised to translate to treatments for solid cancers and non-malignant diseases in the coming years.

The emerging scenario of immunotherapy for T-cell Acute Lymphoblastic Leukemia: advances, challenges and future perspectives

T-cell acute lymphoblastic leukemia (T-ALL) is a challenging pediatric and adult haematologic disease still associated with an unsatisfactory cure rate. Unlike B-ALL, the availability of novel therapeutic options to definitively improve the life expectancy for relapsed/resistant patients is poor. Indeed, the shared expression of surface targets among normal and neoplastic T-cells still limits the efficacy and may induce fratricide effects, hampering the use of innovative immunotherapeutic strategies. However, novel monoclonal antibodies, bispecific T-cell engagers (BTCEs), and chimeric antigen receptors (CAR) T-cells recently showed encouraging results and some of them are in an advanced stage of pre-clinical development or are currently under investigation in clinical trials. Here, we review this exciting scenario focusing on most relevant advances, challenges, and perspectives of the emerging landscape of immunotherapy of T-cell malignancies.

Feasibility and preclinical efficacy of CD7-unedited CD7 CAR T cells for T cell malignancies

Chimeric antigen receptor (CAR)-mediated targeting of T lineage antigens for the therapy of blood malignancies is frequently complicated by self-targeting of CAR T cells or their excessive differentiation driven by constant CAR signaling. Expression of CARs targeting CD7, a pan-T cell antigen highly expressed in T cell malignancies and some myeloid leukemias, produces robust fratricide and often requires additional mitigation strategies, such as CD7 gene editing. In this study, we show fratricide of CD7 CAR T cells can be fully prevented using ibrutinib and dasatinib, the pharmacologic inhibitors of key CAR/CD3ζ signaling kinases. Supplementation with ibrutinib and dasatinib rescued the ex vivo expansion of unedited CD7 CAR T cells and allowed regaining full CAR-mediated cytotoxicity in vitro and in vivo on withdrawal of the inhibitors. The unedited CD7 CAR T cells persisted long term and mediated sustained anti-leukemic activity in two mouse xenograft models of human T cell acute lymphoblastic leukemia (T-ALL) by self-selecting for CD7-, fratricide-resistant CD7 CAR T cells that were transcriptionally similar to control CD7-edited CD7 CAR T cells. Finally, we showed feasibility of cGMP manufacturing of unedited autologous CD7 CAR T cells for patients with CD7+ malignancies and initiated a phase I clinical trial (ClinicalTrials.gov: NCT03690011) using this approach. These results indicate pharmacologic inhibition of CAR signaling enables generating functional CD7 CAR T cells without additional engineering.

Endowing universal CAR T-cell with immune-evasive properties using TALEN-gene editing

Universal CAR T-cell therapies are poised to revolutionize cancer treatment and to improve patient outcomes. However, realizing these advantages in an allogeneic setting requires universal CAR T-cells that can kill target tumor cells, avoid depletion by the host immune system, and proliferate without attacking host tissues. Here, we describe the development of a novel immune-evasive universal CAR T-cells scaffold using precise TALEN-mediated gene editing and DNA matrices vectorized by recombinant adeno-associated virus 6. We simultaneously disrupt and repurpose the endogenous TRAC and B2M loci to generate TCRαβ- and HLA-ABC-deficient T-cells expressing the CAR construct and the NK-inhibitor named HLA-E. This highly efficient gene editing process enables the engineered T-cells to evade NK cell and alloresponsive T-cell attacks and extend their persistence and antitumor activity in the presence of cytotoxic levels of NK cell in vivo and in vitro, respectively. This scaffold could enable the broad use of universal CAR T-cells in allogeneic settings and holds great promise for clinical applications.

Enhanced safety and efficacy of protease-regulated CAR-T cell receptors

Regulatable CAR platforms could circumvent toxicities associated with CAR-T therapy, but existing systems have shortcomings including leakiness and attenuated activity. Here, we present SNIP CARs, a protease-based platform for regulating CAR activity using an FDA-approved small molecule. Design iterations yielded CAR-T cells that manifest full functional capacity with drug and no leaky activity in the absence of drug. In numerous models, SNIP CAR-T cells were more potent than constitutive CAR-T cells and showed diminished T cell exhaustion and greater stemness. In a ROR1-based CAR lethality model, drug cessation following toxicity onset reversed toxicity, thereby credentialing the platform as a safety switch. In the same model, reduced drug dosing opened a therapeutic window that resulted in tumor eradication in the absence of toxicity. SNIP CARs enable remote tuning of CAR activity, which provides solutions to safety and efficacy barriers that are currently limiting progress in using CAR-T cells to treat solid tumors.

Donor T cells for CAR T cell therapy

Adoptive cell therapy using patient-derived chimeric receptor antigen (CAR) T cells redirected against tumor cells has shown remarkable success in treating hematologic cancers. However, wider accessibility of cellular therapies for all patients is needed. Manufacture of patient-derived CAR T cells is limited by prolonged lymphopenia in heavily pre-treated patients and risk of contamination with tumor cells when isolating T cells from patient blood rich in malignant blasts. Donor T cells provide a good source of immune cells for adoptive immunotherapy and can be used to generate universal off-the-shelf CAR T cells that are readily available for administration into patients as required. Genome editing tools such as TALENs and CRISPR-Cas9 and non-gene editing methods such as short hairpin RNA and blockade of protein expression are currently used to enhance CAR T cell safety and efficacy by abrogating non-specific toxicity in the form of graft versus host disease (GVHD) and preventing CAR T cell rejection by the host.

CD3 engagement as a new strategy for allogeneic “off-the-shelf” T cell therapy

Allogeneic “off-the-shelf” (OTS) chimeric antigen receptor T cells (CAR-T cells) hold promise for more accessible CAR-T therapy. Here, we report a novel and simple way to make allogeneic OTS T cells targeting cancer. By engineering T cells with a bispecific T cell engager (BiTE), both TCRαβ and CD3ε expression on the T cell surface are dramatically reduced. BiTE-engineered T (BiTE-T) cells show reduced reaction to TCR stimulation in vitro and have low risk of graft-versus-host disease (GvHD) in vivo. BiTE-T cells down-regulated CD3ε/TCRαβ on bystander T cells by releasing BiTEs. BiTE-T cells produce much fewer cytokines and are comparable to CAR-T cells on anti-cancer efficacy in xenograft mouse models with pre-existing HLA-mismatched T cells. Co-expressing co-stimulatory factors or T cell-promoting cytokines enhanced BiTE-T cells. Our study suggests CD3ε engagement could be a new strategy for allogeneic T cell therapy worthy of further evaluation.

Synthetic Biology in Chimeric Antigen Receptor T (CAR T) Cell Engineering

Synthetic biology is a novel interdisciplinary research area following engineering principles to redesign and construct biological systems for useful purposes. As one of the most notable clinically relevant application of synthetic biology, chimeric antigen receptor (CAR) T cells have demonstrated tremendous success for the treatment of advanced hematological malignancies in recent years. However, various unsolved obstacles limit the widespread application of CAR T cell therapies, including treatment-associated toxicities, antigen heterogeneity, antigen escape, poor CAR T cell persistence and expansion, and particularly inefficient homing, infiltrating into, and surviving within solid tumors. Accordingly, to improve therapeutic efficacy and minimize side effects, innovative CAR design becomes urgently necessary, and researchers are developing numerous methods to overcome the limitations. Here we summarize currently available bioengineering strategies and discuss the future development from a viewpoint of synthetic biology.

Off-the-Shelf Allogeneic CAR-T Cells or Other Immune Effector Cells

“Off-the-shelf” allogeneic CAR TCRab T cells and other immune effector cells, such as natural killer (NK) or gamma delta (gd) T cells, can be premanufactured from healthy donors and may offer alternatives to autologous strategies. However, major barriers, namely HLA disparity resulting in graft versus host disease (GvHD) and host-mediated rejection, must be addressed.

Engineered Removal of PD-1 From the Surface of CD19 CAR-T Cells Results in Increased Activation and Diminished Survival

CAR-T cell therapy is the most advanced way to treat therapy resistant hematologic cancers, in particular B cell lymphomas and leukemias, with high efficiency. Donor T cells equipped ex vivo with chimeric receptor recognize target tumor cells and kill them using lytic granules. CAR-T cells that recognize CD19 marker of B cells (CD19 CAR-T) are considered the gold standard of CAR-T therapy and are approved by FDA. But in some cases, CD19 CAR-T cell therapy fails due to immune suppressive microenvironment. It is shown that tumor cells upregulate expression of PD-L1 surface molecule that binds and increases level and signal provided by PD-1 receptor on the surface of therapeutic CAR-T cells. Induction of this negative signaling results in functional impairment of cytotoxic program in CAR-T cells. Multiple attempts were made to block PD-1 signaling by reducing binding or surface level of PD-1 in CAR-T cells by various means. In this study we co-expressed CD19-CAR with PD-1-specific VHH domain of anti-PD-1 nanobody to block PD-1/PD-L1 signaling in CD19 CAR-T cells. Unexpectedly, despite increased activation of CAR-T cells with low level of PD-1, these T cells had reduced survival and diminished cytotoxicity. Functional impairment caused by disrupted PD-1 signaling was accompanied by faster maturation and upregulation of exhaustion marker TIGIT in CAR-T cells. We conclude that PD-1 in addition to its direct negative effect on CAR-induced signaling is required for attenuation of strong stimulation leading to cell death and functional exhaustion. These observations suggest that PD-1 downregulation should not be considered as the way to improve the quality of therapeutic CAR-T cells.

Advances in chimeric antigen receptor T cells

PURPOSE OF REVIEW

To discuss the important advances in CAR T cell therapy over the past year, focusing on clinical results where available.

RECENT FINDINGS

Approximately 30 years after they were first conceived of and 15 years after the first small-scale single-center clinical trials, the past 3 years represent a major milestone in the development of CAR T cells. In the United States, the Food and Drug Administration (FDA) approved Tisagenlecleucel for the treatment of relapsed/refractory B-ALL and Axicabtagene Ciloleucel, for adults with relapsed/refractory diffuse large B cell lymphoma (R/R DLBCL) in 2017. Tisagenlecleucel received a second indication in adults with R/R DLBCL in 2018. Regulatory approval for CAR T cells was then granted in Europe, Canada, Australia, and Japan. Most recently, in July 2020 the FDA granted regulatory approval to a third CAR T cell product, Brexucabtagene Autoleucel for mantle cell lymphoma. All products target the CD19 antigen but differ in the costimulatory molecule within the CAR construct. Currently, it is unknown whether there are any differences in clinical activity or toxicity between these products.

SUMMARY

The CAR T cell the platform is evolving at a rapid pace and is expected to further improve the therapeutic outcomes of hematological malignancies.

BiTEs better than CAR T cells

This article has a companion Point by Molina and Shah.

Investigational treatment options in phase I and phase II trials for relapsed or refractory acute lymphoblastic leukemia in pediatric patients

Introduction: Upfront treatment of pediatric patients with B-cell acute lymphoblastic leukemia (B-ALL) and T-cell acute lymphoblastic leukemia (T-ALL) results in cure rates of 60-95%, depending on risk factors. However, patients with refractory or relapsed B-ALL or T-ALL have much worse outcomes with conventional chemotherapy, hence treatment of these cohorts with novel agents is a priority.Areas Covered: This paper reviews early phase clinical trials in pediatric leukemia. Investigational antibody therapy, chimeric antigen receptor T-cell (CAR-T), and other targeted therapies are examined. The authors discuss the mechanisms of action, side effects, trial designs, and outcomes and reflect on potential research directions. PubMed and Clinicaltrials.gov were searched from 2010 to present, using keywords 'lymphoblastic leukemia' with filters for pediatric age, Phase 1 clinical trial and Phase 2 clinical trial.Expert Opinion: Pediatric patients with relapsed or refractory leukemia often do not derive additional benefit from intensified conventional chemotherapy approaches which have arguably been maximized in the upfront setting. Therefore, novel approaches, such as immunotherapy and targeted agents should be prioritized. Progress will require commitment from pharmaceutical companies regarding these orphan diagnoses and acknowledgment from regulatory bodies that outcomes are suboptimal with conventional chemotherapy.

Taking T-Cell Oncotherapy Off-the-Shelf

Banked allogeneic or 'off-the-shelf' (OTS) T cells from healthy human donors are being developed to address the limitations of autologous cell therapies. Potential challenges of OTS T cell therapies are associated with their allogeneic origin and the possibility of graft-versus-host disease (GvHD) and host-versus-graft immune reactions. While the risk of GvHD from OTS T cells has been proved to be manageable in clinical studies, approaches to prevent immune rejection of OTS cells are at an earlier stage of development. We provide an overview of strategies to generate OTS cell therapies and mitigate alloreactivity-associated adverse events, with a focus on recent advances for preventing immune rejection.

Off-the-Shelf Chimeric Antigen Receptor T Cells: How Do We Get There?

ABSTRACT

Banked chimeric antigen receptor (CAR) T cells immediately available for off-the-shelf (OTS) application can solve key limitations of patient-specific CAR T-cell products while retaining their potency. The allogeneic nature of OTS cell therapies requires additional measures to minimize graft-versus-host disease and host-versus-graft immune rejection in immunocompetent recipients. In this review, we discuss engineering and manufacturing strategies aimed at minimizing unwanted interactions between allogeneic CAR T cells and the host. Overcoming these limitations will improve safety and antitumor potency of OTS CAR T cells and facilitate their wider use in cancer therapy.

Challenges and Clinical Strategies of CAR T-Cell Therapy for Acute Lymphoblastic Leukemia: Overview and Developments

Chimeric antigen receptor (CAR) T-cell therapy exhibits desirable and robust efficacy in patients with acute lymphoblastic leukemia (ALL). Stimulated by the revolutionized progress in the use of FDA-approved CD19 CAR T cells, novel agents with CAR designs and targets are being produced in pursuit of superior performance. However, on the path from bench to bedside, new challenges emerge. Accessibility is considered the initial barrier to the transformation of this patient-specific product into a commercially available product. To ensure infusion safety, profound comprehension of adverse events and proactive intervention are required. Additionally, resistance and relapse are the most critical and intractable issues in CAR T-cell therapy for ALL, thus precluding its further development. Understanding the limitations through up-to-date insights and characterizing multiple strategies will be critical to leverage CAR T-cell therapy flexibly for use in clinical situations. Herein, we provide an overview of the application of CAR T-cell therapy in ALL, emphasizing the main challenges and potential clinical strategies in an effort to promote a standardized set of treatment paradigms for ALL.

Overcoming key challenges in cancer immunotherapy with engineered T cells

PURPOSE OF REVIEW

A number of clinical trials are currently testing chimeric antigen receptor (CAR) and T cell receptor (TCR) engineered T cells for the treatment of haematologic malignancies and selected solid tumours, and CD19-CAR-T cells have produced impressive clinical responses in B-cell malignancies. Here, we summarize the current state of the field, highlighting the key aspects required for the optimal application of CAR and TCR-engineered T cells for cancer immunotherapy.

RECENT FINDINGS

Toxicities, treatment failure and disease recurrence have been observed at different rates and kinetics. Several strategies have been designed to overcome these hurdles: the identification and combination of known and new antigens, together with the combination of immunotherapeutic and classical approaches may overcome cancer immune evasion. New protocols for genetic modification and T cell culture may improve the overall fitness of cellular products and their resistance to hostile tumour immunomodulatory signals. Finally, the schedules of T cell administration and toxicity management have been adapted to improve the safety of this transformative therapeutic approach.

SUMMARY

In order to develop effective adoptive T cell treatments for cancer, therapeutic optimization of engineered CAR and TCR T cells is crucial, by simultaneously focusing on intrinsic and extrinsic factors. This review focuses on the innovative approaches designed and tested to overcome the hurdles encountered so far in the clinical practice, with new excitement on novel laboratory insights and ongoing clinical investigations.

CRISPR-Cas, a robust gene-editing technology in the era of modern cancer immunotherapy

Cancer immunotherapy has been emerged as a promising strategy for treatment of a broad spectrum of malignancies ranging from hematological to solid tumors. One of the principal approaches of cancer immunotherapy is transfer of natural or engineered tumor-specific T-cells into patients, a so called "adoptive cell transfer", or ACT, process. Construction of allogeneic T-cells is dependent on the employment of a gene-editing tool to modify donor-extracted T-cells and prepare them to specifically act against tumor cells with enhanced function and durability and least side-effects. In this context, CRISPR technology can be used to produce universal T-cells, equipped with recombinant T cell receptor (TCR) or chimeric antigen receptor (CAR), through multiplex genome engineering using Cas nucleases. The robust potential of CRISPR-Cas in preparing the building blocks of ACT immunotherapy has broaden the application of such therapies and some of them have gotten FDA approvals. Here, we have collected the last investigations in the field of immuno-oncology conducted in partnership with CRISPR technology. In addition, studies that have addressed the challenges in the path of CRISPR-mediated cancer immunotherapy, as well as pre-treatment applications of CRISPR-Cas have been mentioned in detail.

Nanotechnology and immunoengineering: How nanotechnology can boost CAR-T therapy

Chimeric antigen receptor (CAR) therapy has achieved remarkable clinical efficacy against hematological cancers and has been approved by FDA for treatment of B-cell tumors. However, the complex manufacturing process and limited success in solid tumors hamper its widespread applications, thus prompting the development of new strategies for overcoming the abovementioned hurdles. In the last decade, nanotechnology has provided sustainable strategies for improving cancer immunotherapy through vaccine development and delivery of immunomodulatory drugs. Nanotechnology can boost CAR-T therapy and may overcome the existing challenges by emerging as a carrier for CAR-T therapy or in combination with CAR-T, it may inhibit solid tumors more effectively than conventional approaches. The revealing of cellular mechanisms, barriers and potential strategies that could be used to manipulate and/or modify cells would enable unprecedented advances in nanotechnology for biologics delivery. This review outlines the journey and barriers of nanoparticles (NPs) across the cell. Subsequently, the approaches to tackle the barriers and strategies to modulate NPs as a carrier for CAR-T therapy are discussed. Finally, the role of NPs in CAR-T therapy and the potential challenges are summarized. This review aims to provide the readers with a detailed overview of NP-based CAR-T therapy research and distil this information into an accessible form conducive to design desired CAR-T therapy using NP approach. STATEMENT OF SIGNIFICANCE: Chimeric antigen receptor (CAR) T-cell therapy is the most vibrant field in immuno-oncology today, with enormous benefits to patients with B-cell malignancies. However, a rapid and straightforward procedure for CAR-T generation is an exigent need to broaden its therapeutic avenue. Nanotechnology has emerged as a novel alternative approach for CAR-T generation. To the best of our knowledge, this is the first in-depth review that briefly highlights the various aspects of nanotechnology in CAR-T therapy, including the strategies to brand NPs as an effective carrier for CAR cargo, its potential advantages, challenges, and future roadmap. It provides readers with a detailed overview of NP-based CAR-T therapy research, and researchers would be able to distill this information into an accessible form conducive to design the desired CAR therapy using the nanotechnology approach.

Recent Advances in Allogeneic CAR-T Cells

In recent decades, great advances have been made in the field of tumor treatment. Especially, cell-based therapy targeting tumor associated antigen (TAA) has developed tremendously. T cells were engineered to have the ability to attack tumor cells by generating CAR constructs consisting of genes encoding scFv, a co-stimulatory domain (CD28 or TNFRSF9), and CD247 signaling domains for T cell proliferation and activation. Principally, CAR-T cells are activated by recognizing TAA by scFv on the T cell surface, and then signaling domains inside cells connected by scFv are subsequently activated to induce downstream signaling pathways involving T cell proliferation, activation, and production of cytokines. Many efforts have been made to increase the efficacy and persistence and also to decrease T cell exhaustion. Overall, allogeneic and universal CAR-T generation has attracted much attention because of their wide and prompt usage for patients. In this review, we summarized the current techniques for generation of allogeneic and universal CAR-T cells along with their disadvantages and limitations that still need to be overcome.

T Cell Reprogramming Against Cancer

Advances in academic and clinical studies during the last several years have resulted in practical outcomes in adoptive immune therapy of cancer. Immune cells can be programmed with molecular modules that increase their therapeutic potency and specificity. It has become obvious that successful immunotherapy must take into account the full complexity of the immune system and, when possible, include the use of multifactor cell reprogramming that allows fast adjustment during the treatment. Today, practically all immune cells can be stably or transiently reprogrammed against cancer. Here, we review works related to T cell reprogramming, as the most developed field in immunotherapy. We discuss factors that determine the specific roles of αβ and γδ T cells in the immune system and the structure and function of T cell receptors in relation to other structures involved in T cell target recognition and immune response. We also discuss the aspects of T cell engineering, specifically the construction of synthetic T cell receptors (synTCRs) and chimeric antigen receptors (CARs) and the use of engineered T cells in integrative multifactor therapy of cancer.

Targeting T cell malignancies using CAR-based immunotherapy: challenges and potential solutions

Chimeric antigen receptor (CAR) T cell therapy has been successful in treating B cell malignancies in clinical trials; however, fewer studies have evaluated CAR T cell therapy for the treatment of T cell malignancies. There are many challenges in translating this therapy for T cell disease, including fratricide, T cell aplasia, and product contamination. To the best of our knowledge, no tumor-specific antigen has been identified with universal expression on cancerous T cells, hindering CAR T cell therapy for these malignancies. Numerous approaches have been assessed to address each of these challenges, such as (i) disrupting target antigen expression on CAR-modified T cells, (ii) targeting antigens with limited expression on T cells, and (iii) using third party donor cells that are either non-alloreactive or have been genome edited at the T cell receptor α constant (TRAC) locus. In this review, we discuss CAR approaches that have been explored both in preclinical and clinical studies targeting T cell antigens, as well as examine other potential strategies that can be used to successfully translate this therapy for T cell disease.

Engineering strategies to overcome the current roadblocks in CAR T cell therapy

T cells genetically engineered to express chimeric antigen receptors (CARs) have proven — and impressive — therapeutic activity in patients with certain subtypes of B cell leukaemia or lymphoma, with promising efficacy also demonstrated in patients with multiple myeloma. Nevertheless, various barriers restrict the efficacy and/or prevent the widespread use of CAR T cell therapies in these patients as well as in those with other cancers, particularly solid tumours. Key challenges relating to CAR T cells include severe toxicities, restricted trafficking to, infiltration into and activation within tumours, suboptimal persistence in vivo, antigen escape and heterogeneity, and manufacturing issues. The evolution of CAR designs beyond the conventional structures will be necessary to address these limitations and to expand the use of CAR T cells to a wider range of malignancies. Investigators are addressing the current obstacles with a wide range of engineering strategies in order to improve the safety, efficacy and applicability of this therapeutic modality. In this Review, we discuss the innovative designs of novel CAR T cell products that are being developed to increase and expand the clinical benefits of these treatments in patients with diverse cancers.

Chimeric antigen receptor (CAR) T cell therapy, the first approved therapeutic approach with a genetic engineering component, holds substantial promise in the treatment of a range of cancers but is nevertheless limited by various challenges, including toxicities, intrinsic and acquired resistance mechanisms, and manufacturing issues. In this Review, the authors describe the innovative approaches to the engineering of CAR T cell products that are providing solutions to these challenges and therefore have the potential to considerably improve the safety and effectiveness of treatment.

Chimeric antigen receptor (CAR) T cells have induced remarkable responses in patients with certain haematological malignancies, yet various barriers restrict the efficacy and/or prevent the widespread use of this treatment.

Investigators are addressing these challenges with engineering strategies designed to improve the safety, efficacy and applicability of CAR T cell therapy.

CARs have modular components, and therefore the optimal molecular design of the CAR can be achieved through many variations of the constituent protein domains.

Toxicities currently associated with CAR T cell therapy can be mitigated using engineering strategies to make CAR T cells safer and that potentially broaden the range of tumour-associated antigens that can be targeted by overcoming on-target, off-tumour toxicities.

CAR T cell efficacy can be enhanced by using engineering strategies to address the various challenges relating to the unique biology of diverse haematological and solid malignancies.

Strategies to address the manufacturing challenges can lead to an improved CAR T cell product for all patients.

Dynamic Profiling of Antitumor Activity of CAR T Cells Using Micropatterned Tumor Arrays

Cancer immunotherapy based on the engineering of chimeric antigen receptors (CAR) on T cells has emerged as one of the most promising new therapies for patients with B-cell malignancies. Preclinical assessments of essential CAR T cell functions such as trafficking and cytotoxicity are critical for accelerating the development of highly effective therapeutic candidates. However, current tools for evaluating CAR-T functions lack sufficient precision. Here, a micropatterned tumor array (MiTA) is described that enables detailed and dynamic characterization of CAR T cell trafficking toward tumor-cell islands and subsequent killing of tumor cells. It is shown that CAR T cells often merge into large clusters that envelop and kill the tumor cells with high efficiency. Significant differences are also measured between CAR T cells from different donors and between various CAR T cell constructs. Overall, the assay allows for multifaceted, dynamic, high-content evaluation of CAR T trafficking, clustering, and killing and could eventually become a useful tool for immune-oncology research and preclinical assessments of cell-based immunotherapies.

Human protein paucimannosylation: cues from the eukaryotic kingdoms

Paucimannosidic proteins (PMPs) are bioactive glycoproteins carrying truncated α- or β-mannosyl-terminating asparagine (N)-linked glycans widely reported across the eukaryotic domain. Our understanding of human PMPs remains limited, despite findings documenting their existence and association with human disease glycobiology. This review comprehensively surveys the structures, biosynthetic routes and functions of PMPs across the eukaryotic kingdoms with the aim of synthesising an improved understanding on the role of protein paucimannosylation in human health and diseases. Convincing biochemical, glycoanalytical and biological data detail a vast structural heterogeneity and fascinating tissue- and subcellular-specific expression of PMPs within invertebrates and plants, often comprising multi-α1,3/6-fucosylation and β1,2-xylosylation amongst other glycan modifications and non-glycan substitutions e.g. O-methylation. Vertebrates and protists express less-heterogeneous PMPs typically only comprising variable core fucosylation of bi- and trimannosylchitobiose core glycans. In particular, the Manα1,6Manβ1,4GlcNAc(α1,6Fuc)β1,4GlcNAcβAsn glycan (M2F) decorates various human neutrophil proteins reportedly displaying bioactivity and structural integrity demonstrating that they are not degradation products. Less-truncated paucimannosidic glycans (e.g. M3F) are characteristic glycosylation features of proteins expressed by human cancer and stem cells. Concertedly, these observations suggest the involvement of human PMPs in processes related to innate immunity, tumorigenesis and cellular differentiation. The absence of human PMPs in diverse bodily fluids studied under many (patho)physiological conditions suggests extravascular residence and points to localised functions of PMPs in peripheral tissues. Absence of PMPs in Fungi indicates that paucimannosylation is common, but not universally conserved, in eukaryotes. Relative to human PMPs, the expression of PMPs in plants, invertebrates and protists is more tissue-wide and constitutive yet, similar to their human counterparts, PMP expression remains regulated by the physiology of the producing organism and PMPs evidently serve essential functions in development, cell-cell communication and host-pathogen/symbiont interactions. In most PMP-producing organisms, including humans, the N-acetyl-β-hexosaminidase isoenzymes and linkage-specific α-mannosidases are glycoside hydrolases critical for generating PMPs via N-acetylglucosaminyltransferase I (GnT-I)-dependent and GnT-I-independent truncation pathways. However, the identity and structure of many species-specific PMPs in eukaryotes, their biosynthetic routes, strong tissue- and development-specific expression, and diverse functions are still elusive. Deep exploration of these PMP features involving, for example, the characterisation of endogenous PMP-recognising lectins across a variety of healthy and N-acetyl-β-hexosaminidase-deficient human tissue types and identification of microbial adhesins reactive to human PMPs, are amongst the many tasks required for enhanced insight into the glycobiology of human PMPs. In conclusion, the literature supports the notion that PMPs are significant, yet still heavily under-studied biomolecules in human glycobiology that serve essential functions and create structural heterogeneity not dissimilar to other human N-glycoprotein types. Human PMPs should therefore be recognised as bioactive glycoproteins that are distinctly different from the canonical N-glycoprotein classes and which warrant a more dedicated focus in glycobiological research.

A long way to the battlefront: CAR T cell therapy against solid cancers

Chimeric antigen receptors (CARs) are engineered synthetic receptors that redirect and reprogram T cells to tumor surface antigens for subsequent eradication. The unprecedented efficacy of CD19-CAR T cells against B-cell malignancies has inspired oncologists to extend these efforts for the treatment of solid tumors. However, limited success has been achieved so far, partially due to some of the formidable challenges, e.g. suppression of full activation, inhibition of T cell localization, lacking of ideal targets, inefficient trafficking and infiltration, immunosuppression of microenvironment, and the probability of off targets and associated side effects. Significant progresses have being made recently. Thus, an updated summary is urgently needed. Here in this review, we discuss the advantages and some of the key hurdles encountered by CAR T cell therapy in solid tumors as well as the strategies adopted to improve therapeutic outcomes of this approach. Continuing efforts to increase therapeutic potential and decrease the adverse effects of adaptive cell transfer are suggested as well.

Switching on the green light for chimeric antigen receptor T-cell therapy

Adoptive cellular therapy involving genetic modification of T cells with chimeric antigen receptor (CAR) transgene offers a promising strategy to broaden the efficacy of this approach for the effective treatment of cancer. Although remarkable antitumor responses have been observed following CAR T‐cell therapy in a subset of B‐cell malignancies, this has yet to be extended in the context of solid cancers. A number of promising strategies involving reprogramming the tumor microenvironment, increasing the specificity and safety of gene‐modified T cells and harnessing the endogenous immune response have been tested in preclinical models that may have a significant impact in patients with solid cancers. This review will discuss these exciting new developments and the challenges that must be overcome to deliver a more sustained and potent therapeutic response.

Allogeneic CAR T cell therapies for leukemia

Allogeneic chimeric antigen receptor T (CAR T) cells can offer advantages over autologous T cell therapies, including the availability of "fit" cells for production, and elimination of risks associated with inadvertent transduction of leukemic blasts. However, allogeneic T cell therapies must address HLA barriers and conventionally rely on the availability of a suitable HLA-matched donor if graft-vs-host-disease and rejection effects are to be avoided. More recently, the incorporation of additional genome editing manipulations, to disrupt T cell receptor expression and address other critical pathways have been explored. Clinical trials are underway investigating non-HLA matched T cells expressing anti-CD19 CARs for the treatment of B cell acute lymphoblastic leukemia (B-ALL) and anti-CD123 CAR for acute myeloid leukemia (AML). Such approaches continue to be refined and improved to widen accessibility and reduce the cost of T cell therapies for a wider range of conditions.

Blocking expression of inhibitory receptor NKG2A overcomes tumor resistance to NK cells

A key mechanism of tumor resistance to immune cells is mediated by expression of peptide-loaded HLA-E in tumor cells, which suppresses natural killer (NK) cell activity via ligation of the NK inhibitory receptor CD94/NKG2A. Gene expression data from approximately 10,000 tumor samples showed widespread HLAE expression, with levels correlating with those of KLRC1 (NKG2A) and KLRD1 (CD94). To bypass HLA-E inhibition, we developed a way to generate highly functional NK cells lacking NKG2A. Constructs containing a single-chain variable fragment derived from an anti-NKG2A antibody were linked to endoplasmic reticulum-retention domains. After retroviral transduction in human peripheral blood NK cells, these NKG2A Protein Expression Blockers (PEBLs) abrogated NKG2A expression. The resulting NKG2Anull NK cells had higher cytotoxicity against HLA-E-expressing tumor cells. Transduction of anti-NKG2A PEBL produced more potent cytotoxicity than interference with an anti-NKG2A antibody and prevented de novo NKG2A expression, without affecting NK cell proliferation. In immunodeficient mice, NKG2Anull NK cells were significantly more powerful than NKG2A+ NK cells against HLA-E-expressing tumors. Thus, NKG2A downregulation evades the HLA-E cancer immune-checkpoint, and increases the anti-tumor activity of NK cell infusions. Because this strategy is easily adaptable to current protocols for clinical-grade immune cell processing, its clinical testing is feasible and warranted.

Chimeric Antigen Receptors for T-Cell Malignancies

Development of chimeric antigen receptor (CAR)-modified T cells for the treatment of T-lineage leukemia and lymphoma has encountered several unique challenges. The most widely expressed tumor antigen targets for malignant T cells are often also expressed on non-malignant T cells. Transducing T cells with CARs targeted to these shared antigens can therefore promote over-activation or fratricide of CAR T cells, reducing their therapeutic potency. If fratricide is resolved, clinical CAR T cell activity may eliminate normal T-cell subsets and cause temporary immunosuppression. In this review, we summarize the preclinical development of CAR-based therapies for T-cell malignancies and discuss strategies to minimize toxicities associated with on-target fratricide and off-tumor activity.

CAR T-cells for T-cell malignancies: challenges in distinguishing between therapeutic, normal, and neoplastic T-cells

Chimeric antigen receptor (CAR) T-cells targeting CD19 demonstrated remarkable efficacy for the treatment of B-cell malignancies. The development of CAR T-cells against T-cell malignancies appears more challenging due to the similarities between the therapeutic, normal and malignant T-cells. The obstacles include CAR T-cell fratricide, T-cell aplasia, and contamination of CAR T-cell products with malignant T-cells. Here, we review these challenges and propose solutions to overcome these limitations.

Dawn of Chimeric Antigen Receptor T Cell Therapy in Non-Hodgkin Lymphoma

Two Chimeric Antigen Receptor (CAR) T cell therapies are now approved for the treatment of relapsed and refractory large cell lymphomas, with many others under development. The dawn of CAR T cell therapy in non-Hodgkin Lymphoma (NHL) has been characterized by rapid progress and high response rates, with a subset of patients experiencing durable benefit. In this review, we describe commercially available and investigational CAR T cell therapies, including product characteristics and clinical outcomes. We review patient selection, with an emphasis on sequencing cell therapy options in the refractory setting. Finally, we discuss durability of response, highlighting mechanisms of escape and investigational approaches to prevent and treat relapse after CAR T cell therapy.