Current updates on generations, approvals, and clinical trials of CAR T-cell therapy

Advancements in tumor-infiltrating lymphocytes: Historical insights, contemporary milestones, and future directions in oncology therapy

Tumor-infiltrating lymphocytes (TILs) are a subtype of immune cells that infiltrate and accumulate within tumors. Studies proved that TILs can be used as prognostic and predictive markers for cancer patients' responses to immunotherapy. This review explores the modern knowledge of TILs, the challenges and opportunities for utilizing TILs in cancer treatment, such as the rise of therapies under TIL circumstances, the identification of biomarkers for TIL activity, and methods used to isolate and expand TILs for therapeutic use. Ongoing clinical trials and promising results in different cancer types are highlighted, including melanoma, ovarian, and colorectal cancer. This also focuses on ongoing efforts to improve TIL-based therapies by identifying the specific subsets of TILs that are most effective in treating cancer and developing methods to increase the functionality and persistence of TILs in the tumor microenvironment. The article recapitulates the present state TILs therapy, ongoing research, and improvements to its potency.

Pre-Clinical Models for CAR T-Cell Therapy for Glioma

Immunotherapy represents a transformative shift in cancer treatment. Among myriad immune-based approaches, chimeric antigen receptor (CAR) T-cell therapy has shown promising results in treating hematological malignancies. Despite aggressive treatment options, the prognosis for patients with malignant brain tumors remains poor. Research leveraging CAR T-cell therapy for brain tumors has surged in recent years. Pre-clinical models are crucial in evaluating the safety and efficacy of these therapies before they advance to clinical trials. However, current models recapitulate the human tumor environment to varying degrees. Novel in vitro and in vivo techniques offer the opportunity to validate CAR T-cell therapies but also have limitations. By evaluating the strengths and weaknesses of various pre-clinical glioma models, this review aims to provide a roadmap for the development and pre-clinical testing of CAR T-cell therapies for brain tumors.

Antigen escape in CAR-T cell therapy: Mechanisms and overcoming strategies

Chimeric antigen receptor T (CAR-T) cell therapy has shown promise in treating hematological malignancies and certain solid tumors. However, its efficacy is often hindered by negative relapses resulting from antigen escape. This review firstly elucidates the mechanisms underlying antigen escape during CAR-T cell therapy, including the enrichment of pre-existing target-negative tumor clones, antigen gene mutations or alternative splicing, deficits in antigen processing, antigen redistribution, lineage switch, epitope masking, and trogocytosis-mediated antigen loss. Furthermore, we summarize various strategies to overcome antigen escape, evaluate their advantages and limitations, and propose future research directions. Thus, we aim to provide valuable insights to enhance the effectiveness of CAR-T cell therapy.

The Current Landscape of Secondary Malignancies after CAR T-Cell Therapies: How Could Malignancies Be Prevented?

Chimeric antigen receptor (CAR) T-cell therapies have revolutionised the field of haematological malignancies by achieving impressive remission rates in patients with highly refractory haematological malignancies, improving overall survival. To date, six commercial anti-CD19 and anti-BCMA CAR T-cell products have been approved by the Food and Drug Administration (FDA) for the treatment of relapsed/refractory B-cell haematological malignancies and multiple myeloma. The indications for CAR T-cell therapies are gradually expanding, with these therapies being investigated in a variety of diseases, including non-malignant ones. Despite the great success, there are several challenges surrounding CAR T-cell therapies, such as non-durable responses and high-grade toxicities. In addition, a new safety concern was added by the FDA on 28 November 2023 following reports of T-cell malignancies in patients previously treated with either anti-CD19 or anti-BCMA autologous CAR T-cell therapies both in clinical trials and in the real-world setting. Since then, several reports have been published presenting the incidence and analysing the risks of other secondary malignancies after CAR T-cell therapies. In this opinion article, the current landscape of secondary malignancies after CAR T-cell therapies is presented, along with a proposed strategy for future research aiming at potentially diminishing or abrogating the risk of developing secondary malignancies after CAR T-cell therapies.

Current Insights into CAR T-Cell-Based Therapies for Myelodysplastic Syndrome

Myelodysplastic syndromes (MDS) are due to defective hematopoiesis in bone marrow characterized by cytopenia and dysplasia of blood cells, with a varying degree of risk of acute myeloid leukemia (AML). Currently, the only potentially curative strategy is hematopoietic stem cell transplantation (HSCT). Many patients are ineligible for HSCT, due to late diagnosis, presence of co-morbidities, old age and complications likely due to graft-versus-host disease (GvHD). As a consequence, patients with MDS are often treated conservatively with blood transfusions, chemotherapy, immunotherapy etc. based on the grade and manifestations of MDS. The development of chimeric antigen receptor (CAR)-T cell therapy has revolutionized immunotherapy for hematological malignancies, as evidenced by a large body of literature. However, resistance and toxicity associated with it are also a challenge. Hence, there is an urgent need to develop new strategies for immunological and hematopoetic management of MDS. Herein, we discuss current limitations of CAR T-cell therapy and summarize novel approaches to mitigate this. Further, we discuss the in vivo activation of tumor-specific T cells, immune check inhibitors (ICI) and other approaches to normalize the bone marrow milieu for the management of MDS.

CAR-T therapy for ovarian cancer: Recent advances and future directions

Ovarian cancer (OC) is a common gynecological tumor with high mortality, which is difficult to control its progression with conventional treatments and is prone to recurrence. Recent studies have identified OC as an immunogenic tumor that can be recognized by the host immune system. Immunotherapy for OC is being evaluated, but approaches such as immune checkpoint inhibitors have limited efficacy, adoptive cell therapy is an alternative therapy, in which CAR(chimeric antigen receptor)-T therapy has been applied to the clinical treatment of hematological malignancies. In addition, CAR-NK and CAR-macrophage (CAR-M) have also shown great potential in the treatment of solid tumors. Here, we discuss recent advances in preclinical and clinical studies of CAR-T for OC treatment, introduce the efforts made by researchers to modify the structure of CAR in order to achieve effective OC immunotherapy, as well as the research status of CAR-NK and CAR-M, and highlight emerging therapeutic opportunities that can be utilized to improve the survival of patients with OC using CAR-based adoptive cell therapy.

Current Trends and Innovative Approaches in Cancer Immunotherapy

Immunotherapy is one of the most promising therapeutic approaches in the field of cancer treatment. As a tumor progresses, tumor cells employ an array of immune-regulatory mechanisms to suppress immune responses within the tumor microenvironment. Using our understanding of these mechanisms, cancer immunotherapy has been developed to enhance the immune system's effectiveness in treating cancer. Numerous cancer immunotherapies are currently in clinical use, yet many others are either in different stages of development or undergoing clinical studies. In this paper, we briefly discuss the features and current status of cancer immunotherapies. This includes the application of monoclonal antibodies, immune checkpoint inhibitors, adoptive cell therapy, cytokine therapy, cancer vaccines, and gene therapy, all of which have gained significant recognition in clinical practice. Additionally, we discuss limitations that may hinder successful clinical utilization and promising strategies, such as combining immunotherapy with nanotechnology.

The Spectrum of CAR Cellular Effectors: Modes of Action in Anti-Tumor Immunity

Chimeric antigen receptor-T cells have spearheaded the field of adoptive cell therapy and have shown remarkable results in treating hematological neoplasia. Because of the different biology of solid tumors compared to hematological tumors, response rates of CAR-T cells could not be transferred to solid entities yet. CAR engineering has added co-stimulatory domains, transgenic cytokines and switch receptors to improve performance and persistence in a hostile tumor microenvironment, but because of the inherent cell type limitations of CAR-T cells, including HLA incompatibility, toxicities (cytokine release syndrome, neurotoxicity) and high costs due to the logistically challenging preparation process for autologous cells, the use of alternative immune cells is gaining traction. NK cells and γδ T cells that do not need HLA compatibility or macrophages and dendritic cells with additional properties such as phagocytosis or antigen presentation are increasingly seen as cellular vehicles with potential for application. As these cells possess distinct properties, clinicians and researchers need a thorough understanding of their peculiarities and commonalities. This review will compare these different cell types and their specific modes of action seen upon CAR activation.

Application of CAR-T cell therapy targeting mesothelin in solid tumor treatment

Chimeric antigen receptor (CAR)-T-cell therapy is one of the most effective immunotherapies. CAR-T-cell therapy has achieved great success in the treatment of hematological malignancies. However, due to the characteristics of solid malignant tumors, such as on-target effects, off-tumor toxicity, an immunosuppressive tumor microenvironment (TME), and insufficient trafficking, CAR-T-cell therapy for solid tumors is still in the exploration stage. Mesothelin (MSLN) is a molecule expressed on the surface of various solid malignant tumor cells that is suitable as a target of tumor cells with high MSLN expression for CAR-T-cell therapy. This paper briefly described the development of CAR-T cell therapy and the structural features of MSLN, and especially summarized the strategies of structure optimization of MSLN-targeting CAR-T-cells and the enhancement methods of MSLN-targeting CAR-T cell anti-tumor efficacy by summarizing some preclinical experiment and clinical trials. When considering MSLN-targeting CAR-T-cell therapy as an example, this paper summarizes the efforts made by researchers in CAR-T-cell therapy for solid tumors and summarizes feasible treatment plans by integrating the existing research results.

Immune landscape of hepatocellular carcinoma: From dysregulation of the immune responses to the potential immunotherapies

Hepatocellular carcinoma (HCC) presents a considerable global health burden due to its late diagnosis and high morbidity. The liver's specific anatomical and physiological features expose it to various antigens, requiring precise immune regulation. To the best of our knowledge, this is the first time that a comprehensive overview of the interactions between the immune system and gut microbiota in the development of HCC, as well as the relevant therapeutic approaches are discussed. Dysregulation of immune compartments within the liver microenvironment drives HCC pathogenesis, characterized by elevated regulatory cells such as regulatory T cells (Tregs), myeloid-derived suppressor cells, and M2 macrophages as well as suppressive molecules, alongside reduced number of effector cells like T cells, natural killer cells, and M1 macrophages. Dysbiosis of gut microbiota also contributes to HCC by disrupting intestinal barrier integrity and triggering overactivated immune responses. Immunotherapy approaches, particularly immune checkpoint inhibitors, have exhibited promise in HCC management, yet adoptive cell therapy and cancer vaccination research are in the early steps with relatively less favorable outcomes. Further understanding of immune dysregulation, gut microbiota involvement, and therapeutic combination strategies are essential for advancing precision immunotherapy in HCC.

The Art of Bioimmunogenomics (BIGs) 5.0 in CAR-T Cell Therapy for Lymphoma Management

Purpose

Lymphoma, the most predominant neoplastic disorder, is divided into Hodgkin and Non-Hodgkin Lymphoma classifications. Immunotherapeutic modalities have emerged as essential methodologies in combating lymphoid malignancies. Chimeric Antigen Receptor (CAR) T cells exhibit promising responses in chemotherapy-resistant B-cell non-Hodgkin lymphoma cases.

Methods

This comprehensive review delineates the advancement of CAR-T cell therapy as an immunotherapeutic instrument, the selection of lymphoma antigens for CAR-T cell targeting, and the conceptualization, synthesis, and deployment of CAR-T cells. Furthermore, it encompasses the advantages and disadvantages of CAR-T cell therapy and the prospective horizons of CAR-T cells from a computational research perspective. In order to improve the design and functionality of artificial CARs, there is a need for TCR recognition investigation, followed by the implementation of a quality surveillance methodology.

Results

Various lymphoma antigens are amenable to CAR-T cell targeting, such as CD19, CD20, CD22, CD30, the kappa light chain, and ROR1. A notable merit of CAR-T cell therapy is the augmentation of the immune system's capacity to generate tumoricidal activity in patients exhibiting chemotherapy-resistant lymphoma. Nevertheless, it also introduces manufacturing impediments that are laborious, technologically demanding, and financially burdensome. Physical, physicochemical, and physiological limitations further exacerbate the challenge of treating solid neoplasms with CAR-T cells.

Conclusion

While the efficacy and safety of CAR-T cell immunotherapy remain subjects of fervent investigation, the promise of this cutting-edge technology offers valuable insights for the future evolution of lymphoma treatment management approaches. Moreover, CAR-T cell therapies potentially benefit patients, motivating regulatory bodies to foster international collaboration.

Contemporary Approaches to Immunotherapy of Solid Tumors

In recent years, the arrival of the immunotherapy industry has introduced the possibility of providing transformative, durable, and potentially curative outcomes for various forms of malignancies. However, further research has shown that there are a number of issues that significantly reduce the effectiveness of immunotherapy, especially in solid tumors. First of all, these problems are related to the protective mechanisms of the tumor and its microenvironment. Currently, major efforts are focused on overcoming protective mechanisms by using different adoptive cell therapy variants and modifications of genetically engineered constructs. In addition, a complex workforce is required to develop and implement these treatments. To overcome these significant challenges, innovative strategies and approaches are necessary to engineer more powerful variations of immunotherapy with improved antitumor activity and decreased toxicity. In this review, we discuss recent innovations in immunotherapy aimed at improving clinical efficacy in solid tumors, as well as strategies to overcome the limitations of various immunotherapies.

CAR-T-Cell-Based Cancer Immunotherapies: Potentials, Limitations, and Future Prospects

Cancer encompasses various elements occurring at the cellular and genetic levels, necessitating an immunotherapy capable of efficiently addressing both aspects. T cells can combat cancer cells by specifically recognizing antigens on them. This innate capability of T cells has been used to develop cellular immunotherapies, but most of them can only target antigens through major histocompatibility complexes (MHCs). New gene-editing techniques such as clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein 9 (CRISPR-cas9) can precisely edit the DNA sequences. CRISPR-cas9 has made it possible to generate genetically engineered chimeric antigen receptors (CARs) that can overcome the problems associated with old immunotherapies. In chimeric antigen receptor T (CAR-T) cell therapy, the patient's T cells are isolated and genetically modified to exhibit synthetic CAR(s). CAR-T cell treatment has shown remarkably positive clinical outcomes in cancers of various types. Nevertheless, there are various challenges that reduce CAR-T effectiveness in solid tumors. It is required to address these challenges in order to make CAR-T cell therapy a better and safer option. Combining CAR-T treatment with other immunotherapies that target multiple antigens has shown positive outcomes. Moreover, recently generated Boolean logic-gated advanced CARs along with artificial intelligence has expanded its potential to treat solid tumors in addition to blood cancers. This review aims to describe the structure, types, and various methods used to develop CAR-T cells. The clinical applications of CAR-T cells in hematological malignancies and solid tumours have been described in detail. In addition, this discussion has addressed the limitations associated with CAR-T cells, explored potential strategies to mitigate CAR-T-related toxicities, and delved into future perspectives.

CAR-T cell therapy: Efficacy in management of cancers, adverse effects, dose-limiting toxicities and long-term follow up

Chimeric Antigen Receptor T-cell (CAR-T) therapy has emerged as a groundbreaking and highly promising approach for the management of cancer. This paper reviews the efficacy of CAR-T therapy in the treatment of various hematological malignancies, also, with a mention of its effect on solid tumors, for which they have not received FDA approval yet. Different common and uncommon side effects are also discussed in this paper, with attention to the effect of each drug separately. By reviewing the recommendations of the FDA for CAR-T therapy research, we have extensively discussed dose-limiting toxicities. This further highlights the need for precise dosing strategies, striking a balance between therapeutic benefits and potential risks. Additionally, we reviewed the long-term follow-up of patients receiving CAR-T therapy to gain valuable insights into response durability and late-onset effects.

The synergistic immunotherapeutic impact of engineered CAR-T cells with PD-1 blockade in lymphomas and solid tumors: a systematic review

Currently, therapies such as chimeric antigen receptor-T Cell (CAR-T) and immune checkpoint inhibitors like programmed cell death protein-1 (PD-1) blockers are showing promising results for numerous cancer patients. However, significant advancements are required before CAR-T therapies become readily available as off-the-shelf treatments, particularly for solid tumors and lymphomas. In this review, we have systematically analyzed the combination therapy involving engineered CAR-T cells and anti PD-1 agents. This approach aims at overcoming the limitations of current treatments and offers potential advantages such as enhanced tumor inhibition, alleviated T-cell exhaustion, heightened T-cell activation, and minimized toxicity. The integration of CAR-T therapy, which targets tumor-associated antigens, with PD-1 blockade augments T-cell function and mitigates immune suppression within the tumor microenvironment. To assess the impact of combination therapy on various tumors and lymphomas, we categorized them based on six major tumor-associated antigens: mesothelin, disialoganglioside GD-2, CD-19, CD-22, CD-133, and CD-30, which are present in different tumor types. We evaluated the efficacy, complete and partial responses, and progression-free survival in both pre-clinical and clinical models. Additionally, we discussed potential implications, including the feasibility of combination immunotherapies, emphasizing the importance of ongoing research to optimize treatment strategies and improve outcomes for cancer patients. Overall, we believe combining CAR-T therapy with PD-1 blockade holds promise for the next generation of cancer immunotherapy.

An Assessment of the Effectiveness and Safety of Chimeric Antigen Receptor T-Cell Therapy in Multiple Myeloma Patients with Relapsed or Refractory Disease: A Systematic Review and Meta-Analysis

Multiple myeloma (MM), the second most common hematologic malignancy, remains incurable, and its incidence is rising. Chimeric Antigen Receptor T-cell (CAR-T cell) therapy has emerged as a novel treatment, with the potential to improve the survival and quality of life of patients with relapsed/refractory multiple myeloma (rrMM). In this systematic review and meta-analysis, conducted in accordance with PRISMA guidelines, we aim to provide a concise overview of the latest developments in CAR-T therapy, assess their potential implications for clinical practice, and evaluate their efficacy and safety outcomes based on the most up-to-date evidence. A literature search conducted from 1 January 2019 to 12 July 2023 on Medline/PubMed, Scopus, and Web of Science identified 2273 articles, of which 29 fulfilled the specified criteria for inclusion. Our results offer robust evidence supporting CAR-T cell therapy's efficacy in rrMM patients, with an encouraging 83.21% overall response rate (ORR). A generally safe profile was observed, with grade ≥ 3 cytokine release syndrome (CRS) at 7.12% and grade ≥ 3 neurotoxicity at 1.37%. A subgroup analysis revealed a significantly increased ORR in patients with fewer antimyeloma regimens, while grade ≥ 3 CRS was more common in those with a higher proportion of high-risk cytogenetics and prior exposure to BCMA therapy.

[Closed-loop synthetic gene circuits for cell-based therapies]

Recent advances in synthetic biology have paved the way for new cellular therapies, using cells capable of autonomously treating chronic diseases. These cells integrate a set of genes functioning in a closed-loop synthetic circuit, delivering a therapeutic effector in response to a specific pathological signal. While promising in mice, these therapies face clinical challenges related to safety and feasibility of in vivo implementation. The latest generations of synthetic circuits aim to address these issues through advanced bioengineering strategies outlined in this article.

Therapeutic potential of third-generation chimeric antigen receptor T cells targeting B cell maturation antigen for treating multiple myeloma

Multiple myeloma (MM) is an incurable hematologic malignancy characterized by the rapid proliferation of malignant plasma cells within the bone marrow. Standard therapies often fail due to patient resistance. The US FDA has approved second-generation chimeric antigen receptor (CAR) T cells targeting B-cell maturation antigen (anti-BCMA-CAR2 T cells) for MM treatment. However, achieving enduring clinical responses remains a challenge in CAR T cell therapy. This study developed third-generation T cells with an anti-BCMA CAR (anti-BCMA-CAR3). The CAR incorporated a fully human scFv specific to BCMA, linked to the CD8 hinge region. The design included the CD28 transmembrane domain, two co-stimulatory domains (CD28 and 4-1BB), and the CD3ζ signaling domain (28BBζ). Lentiviral technology generated these modified T cells, which were compared against anti-BCMA-CAR2 T cells for efficacy against cancer. Anti-BCMA-CAR3 T cells exhibited significantly higher cytotoxic activity against BCMA-expressing cells (KMS-12-PE and NCI-H929) compared to anti-BCMA-CAR2 T cells. At an effector-to-target ratio of 10:1, anti-BCMA-CAR3 T cells induced lysis in 75.5 ± 3.8% of NCI-H929 cells, whereas anti-BCMA-CAR2 T cells achieved 56.7 ± 3.4% (p = 0.0023). Notably, after twelve days of cultivation, anti-BCMA-CAR3 T cells nearly eradicated BCMA-positive cells (4.1 ± 2.1%), while anti-BCMA-CAR2 T cells allowed 36.8 ± 20.1% to survive. This study highlights the superior efficacy of anti-BCMA-CAR3 T cells against both low and high BCMA-expressing MM cells, surpassing anti-BCMA-CAR2 T cells. These findings suggest potential for advancing anti-BCMA-CAR3 T cells in chimeric antigen receptor T (CAR-T) therapy for relapsed/refractory MM.

A new vision of the efficacy of both CAR-NK and CAR-T cells in treating cancers and autoimmune diseases

Chimeric Antigen Receptor (CAR) based therapies are becoming increasingly important in treating patients. CAR-T cells have been shown to be highly effective in the treatment of hematological malignancies. However, harmful therapeutic barriers have been identified, such as the potential for graft-versus-host disease (GVHD), neurotoxicity, and cytokine release syndrome (CRS). As a result, CAR NK-cell therapy is expected to be a new therapeutic option. NK cells act as cytotoxic lymphocytes, supporting the innate immune response against autoimmune diseases and cancer cells by precisely detecting and eliminating malignant cells. Genetic modification of these cells provides a dual approach to the treatment of AD and cancer. It can be used through both CAR-independent and CAR-dependent mechanisms. The use of CAR-based cell therapies has been successful in treating cancer patients, leading to further investigation of this innovative treatment for alternative diseases, including AD. The complementary roles of CAR T and CAR NK cells have stimulated exploration in this area. Our study examines the latest research on the therapeutic effectiveness of these cells in treating both cancer and ADs.

Chimeric antigen receptor T cells in the treatment of osteosarcoma (Review)

Osteosarcoma (OS) is a frequently occurring primary bone tumor, mostly affecting children, adolescents and young adults. Before 1970, surgical resection was the main treatment method for OS, but the clinical results were not promising. Subsequently, the advent of chemotherapy has improved the prognosis of patients with OS. However, there is still a high incidence of metastasis or recurrence, and chemotherapy has several side effects, thus making the 5‑year survival rate markedly low. Recently, chimeric antigen receptor T (CAR‑T) cell therapy represents an alternative immunotherapy approach with significant potential for hematologic malignancies. Nevertheless, the application of CAR‑T cells in the treatment of OS faces numerous challenges. The present review focused on the advances in the development of CAR‑T cells to improve their clinical efficacy, and discussed ways to overcome the difficulties faced by CAR T‑cell therapy for OS.

Update on the current and future use of CAR-T to treat multiple myeloma

Chimeric antigen receptor T-cell (CAR-T) therapy has become an important intervention in the management of relapsed and relapsed/refractory multiple myeloma (MM). Currently, B-cell maturation antigen (BCMA) is the most targeted surface protein due to its ubiquitous expression on plasma cells, with increasing expression of this essential transmembrane protein on malignant plasma cells as patients develop more advanced disease. This review will explore the earliest CAR-T trials in myeloma, discuss important issues involved in CAR-T manufacturing and processing, as well as review current clinical trials that led to the approval of the two commercially available CAR-T products, Idecabtagene vicleucel and ciltacabtagene autoleucel. The most recent data from trials investigating the use of CAR-T as an earlier line of therapy will be presented. Finally, the problem of relapses after CAR-T will be presented, including several theories as to why CAR-T therapies fail and possible clinical caveats. The next generation of MM-specific CAR-T will likely include new targets such as G-protein-coupled receptor class C, Group 5, member D (GPRC5D) and signaling lymphocyte activation molecular Family 7 (SLAMF7). The role of CAR-T in the treatment of MM will undoubtedly increase exponentially in the next decade.

GMP-manufactured CRISPR/Cas9 technology as an advantageous tool to support cancer immunotherapy

BACKGROUND

CRISPR/Cas9 system to treat human-related diseases has achieved significant results and, even if its potential application in cancer research is improving, the application of this approach in clinical practice is still a nascent technology.

MAIN BODY

CRISPR/Cas9 technology is not yet used as a single therapy to treat tumors but it can be combined with traditional treatment strategies to provide personalized gene therapy for patients. The combination with chemotherapy, radiation and immunotherapy has been proven to be a powerful means of screening, identifying, validating and correcting tumor targets. Recently, CRISPR/Cas9 technology and CAR T-cell therapies have been integrated to open novel opportunities for the production of more efficient CAR T-cells for all patients. GMP-compatible equipment and reagents are already available for several clinical-grade systems at present, creating the basis and framework for the accelerated development of novel treatment methods.

CONCLUSION

Here we will provide a comprehensive collection of the actual GMP-grade CRISPR/Cas9-mediated approaches used to support cancer therapy highlighting how this technology is opening new opportunities for treating tumors.

Chimeric Antigen Receptor T Cell Therapy for Hepatocellular Carcinoma: Where Do We Stand?

Hepatocellular carcinoma (HCC) remains a global health challenge that urgently calls for innovative therapeutic strategies. Chimeric antigen receptor T cell (CAR T) therapy has emerged as a promising avenue for HCC treatment. However, the therapeutic efficacy of CAR T immunotherapy in HCC patients is significantly compromised by some major issues including the immunosuppressive environment within the tumor, antigen heterogeneity, CAR T cell exhaustion, and the advanced risk for on-target/off-tumor toxicity. To overcome these challenges, many ongoing preclinical and clinical trials are underway focusing on the identification of optimal target antigens and the decryption of the immunosuppressive milieu of HCC. Moreover, limited tumor infiltration constitutes a significant obstacle of CAR T cell therapy that should be addressed. The continuous effort to design molecular targets for CAR cells highlights the importance for a more practical approach for CAR-modified cell manufacturing. This review critically examines the current landscape of CAR T cell therapy for HCC, shedding light on the changes in innate and adaptive immune responses in the context of HCC, identifying potential CAR T cell targets, and exploring approaches to overcome inherent challenges. Ongoing advancements in scientific research and convergence of diverse treatment modalities offer the potential to greatly enhance HCC patients' care in the future.

Recent advances and current challenges in CAR-T cell therapy

Rapid advancements in the field of immunotherapy have significantly improved cancer treatments. Specifically, an individualized cell-based modality which involves the removal of some of the patient's own white blood cells, including T cells, has revolutionized research in this field. This study focuses on the recent advances and current challenges of Chimeric Antigen Receptor- T (CAR-T) cell therapy and its regulations in the United States (US) and European Union (EU). Understanding the regulatory regimes of CAR-T cell therapy is critical for researchers and manufacturers as they navigate the hurdles of bringing CAR-T cell therapy to the global market. Benefits of CAR-T cell therapy include high response rates and the potential of long-term remissions in some haematological malignancies. However, the drawbacks are still evident including high costs, adverse reactions, and limited efficacy to solid tumours. CAR-T cell therapy is rapidly advancing, with 1231 clinical trials launched globally according to www.clinicalTrial.gov . The future of CAR-T cell therapy holds enormous promise but improving its safety, effectiveness, and availability are still barriers to its successful implementation.

Engineered CAR-T cells: An immunotherapeutic approach for cancer treatment and beyond

Chimeric Antigen Receptor (CAR) T cell therapy is a type of adoptive immunotherapy that offers a promising avenue for enhancing cancer treatment since traditional cancer treatments like chemotherapy, surgery, and radiation therapy have proven insufficient in completely eradicating tumors, despite the relatively positive outcomes. It has been observed that CAR-T cell therapy has shown promising results in treating the majority of hematological malignancies but also have a wide scope for other cancer types. CAR is an extra receptor on the T-cell that helps to increase and accelerate tumor destruction by efficiently activating the immune system. It is made up of three domains, the ectodomain, transmembrane, and the endodomain. The ectodomain is essential for antigen recognition and binding, whereas the co-stimulatory signal is transduced by the endodomain. To date, the Food and Drug Administration (FDA) has granted approval for six CAR-T cell therapies. However, despite its remarkable success, CAR-T therapy is associated with numerous adverse events and has certain limitations. This chapter focuses on the structure and function of the CAR domain, various generations of CAR, and the process of CAR-T cell development, adverse effects, and challenges in CAR-T therapy. CAR-T cell therapy also has scopes in other disease conditions which include systemic lupus erythematosus, multiple sclerosis, and myocardial fibrosis, etc.

Current status and future challenges of CAR-T cell therapy for osteosarcoma

Osteosarcoma, the most common bone malignancy in children and adolescents, poses considerable challenges in terms of prognosis, especially for patients with metastatic or recurrent disease. While surgical intervention and adjuvant chemotherapy have improved survival rates, limitations such as impractical tumor removal or chemotherapy resistance hinder the treatment outcomes. Chimeric antigen receptor (CAR)-T cell therapy, an innovative immunotherapy approach that involves targeting tumor antigens and releasing immune factors, has shown significant advancements in the treatment of hematological malignancies. However, its application in solid tumors, including osteosarcoma, is constrained by factors such as low antigen specificity, limited persistence, and the complex tumor microenvironment. Research on osteosarcoma is ongoing, and some targets have shown promising results in pre-clinical studies. This review summarizes the current status of research on CAR-T cell therapy for osteosarcoma by compiling recent literature. It also proposes future research directions to enhance the treatment of osteosarcoma.

Building safety into CAR-T therapy

Chimeric antigen receptor T cell (CAR-T) therapy is an innovative immunotherapeutic approach that utilizes genetically modified T-cells to eliminate cancer cells using the specificity of a monoclonal antibody (mAb) coupled to the potent cytotoxicity of the T-lymphocyte. CAR-T therapy has yielded significant improvements in relapsed/refractory B-cell malignancies. Given these successes, CAR-T has quickly spread to other hematologic malignancies and is being increasingly explored in solid tumors. From early clinical applications to present day, CAR-T cell therapy has been accompanied by significant toxicities, namely cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and on-target off-tumor (OTOT) effects. While medical management has improved for CRS and ICANS, the ongoing threat of refractory symptoms and unanticipated idiosyncratic toxicities highlights the need for more powerful safety measures. This is particularly poignant as CAR T-cell therapy continues to expand into the solid tumor space, where the risk of unpredictable toxicities remains high. We will review CAR-T as an immunotherapeutic approach including emergence of unique toxicities throughout development. We will discuss known and novel strategies to mitigate these toxicities; additional safety challenges in the treatment of solid tumors, and how the inducible Caspase 9 "safety switch" provides an ideal platform for continued exploration.

The CAR macrophage cells, a novel generation of chimeric antigen-based approach against solid tumors

Today, adoptive cell therapy has many successes in cancer therapy, and this subject is brilliant in using chimeric antigen receptor T cells. The CAR T cell therapy, with its FDA-approved drugs, could treat several types of hematological malignancies and thus be very attractive for treating solid cancer. Unfortunately, the CAR T cell cannot be very functional in solid cancers due to its unique features. This treatment method has several harmful adverse effects that limit their applications, so novel treatments must use new cells like NK cells, NKT cells, and macrophage cells. Among these cells, the CAR macrophage cells, due to their brilliant innate features, are more attractive for solid tumor therapy and seem to be a better candidate for the prior treatment methods. The CAR macrophage cells have vital roles in the tumor microenvironment and, with their direct effect, can eliminate tumor cells efficiently. In addition, the CAR macrophage cells, due to being a part of the innate immune system, attended the tumor sites. With the high infiltration, their therapy modulations are more effective. This review investigates the last achievements in CAR-macrophage cells and the future of this immunotherapy treatment method.

Mechanisms and strategies for safe chimeric antigen receptor T-cell activity control

The clinical application of chimeric antigen receptor (CAR) T-cell therapy has rapidly changed the treatment options for terminally ill patients with defined blood-borne cancer types. However, CAR T-cell therapy can lead to severe therapy-associated toxicities including CAR-related hematotoxicity, ON-target OFF-tumor toxicity, cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS). Just as CAR T-cell therapy has evolved regarding receptor design, gene transfer systems and production protocols, the management of side effects has also improved. However, because of measures taken to abrogate adverse events, CAR T-cell viability and persistence might be impaired before complete remission can be achieved. This has fueled efforts for the development of extrinsic and intrinsic strategies for better control of CAR T-cell activity. These approaches can mediate a reversible resting state or irreversible T-cell elimination, depending on the route chosen. Control can be passive or active. By combination of CAR T-cells with T-cell inhibiting compounds, pharmacologic control, mostly independent of the CAR construct design used, can be achieved. Other strategies involve the genetic modification of T-cells or further development of the CAR construct by integration of molecular ON/OFF switches such as suicide genes. Alternatively, CAR T-cell activity can be regulated intracellularly through a self-regulation function or extracellularly through titration of a CAR adaptor or of a priming small molecule. In this work, we review the current strategies and mechanisms to control activity of CAR T-cells reversibly or irreversibly for preventing and for managing therapy-associated toxicities.

CAR-T cell therapy for hematological malignancies: History, status and promise

For many years, the methods of cancer treatment are usually surgery, chemotherapy and radiation therapy. Although these methods help to improve the condition, most tumors still have a poor prognosis. In recent years, immunotherapy has great potential in tumor treatment. Chimeric antigen receptor T-cell immunotherapy (CAR-T) uses the patient's own T cells to express chimeric antigen receptors. Chimeric antigen receptor (CAR) recognizes tumor-associated antigens and kills tumor cells. CAR-T has achieved good results in the treatment of hematological tumors. In 2017, the FDA approved the first CAR-T for the treatment of B-cell acute lymphoblastic leukemia (ALL). In October of the same year, the FDA approved CAR-T to treat B-cell lymphoma. In order to improve and enhance the therapeutic effect, CAR-T has become a research focus in recent years. The structure of CAR, the targets of CAR-T treatment, adverse reactions and improvement measures during the treatment process are summarized. This review is an attempt to highlight recent and possibly forgotten findings of advances in chimeric antigen receptor T cell for treatment of hematological tumors.

RIPTACs: A groundbreaking approach to drug discovery

Regulated induced proximity targeting chimeras (RIPTACs), a new class of heterobifunctional molecules, show promise in specifically targeting and eliminating cancer cells while leaving healthy cells unharmed. As a groundbreaking drug discovery approach, RIPTACs work by forming a stable complex with two proteins, one specifically found in cancer cells (target protein, TP) and the other pan-essential for cell survival (effector protein, EP), selectively disrupting the function of the EP in cancer cells and causing cell death. Interestingly, the TPs need not be linked to disease progression, broadening the spectrum of potential drug targets. This review summarizes the discovery and recent advances of the RIPTAC strategy. Additionally, it discusses the associated opportunities and challenges as well as future perspectives in this field.

CAR-T cell therapy: Where are we now, and where are we heading?

Chimeric antigen receptor (CAR)-T-cell therapies have exhibited remarkable efficacy in the treatment of hematologic malignancies, with 9 CAR-T-cell products currently available. Furthermore, CAR-T cells have shown promising potential for expanding their therapeutic applications to diverse areas, including solid tumors, myocardial fibrosis, and autoimmune and infectious diseases. Despite these advancements, significant challenges pertaining to treatment-related toxic reactions and relapses persist. Consequently, current research efforts are focused on addressing these issues to enhance the safety and efficacy of CAR-T cells and reduce the relapse rate. This article provides a comprehensive overview of the present state of CAR-T-cell therapies, including their achievements, existing challenges, and potential future developments.

Insight into the Progress in CAR-T Cell Therapy and Combination with Other Therapies for Glioblastoma

Glioblastoma (GBM) is the most common malignant primary brain cancer in adults. It is always resistant to existing treatments, including surgical resection, postoperative radiotherapy, and chemotherapy, which leads to a dismal prognosis and a high relapse rate. Therefore, novel curative therapies are urgently needed for GBM. Chimeric antigen receptor T (CAR-T) cell therapy has significantly improved life expectancy for hematological malignancies patients, and thus it increases the interest in applying CAR-T cell therapy for solid tumors. In the recently published research, it is indicated that there are numerous obstacles to achieve clinical benefits for solid tumors, especially for GBM, because of GBM anatomical characteristics (the blood-brain barrier and suppressive tumor microenvironment) and the tumor heterogeneity. CAR-T cells are difficult to penetrate blood-brain barrier, and immunosuppressive tumor microenvironment (TME), which induces CAR-T cell exhaustion, impairs CAR-T cell therapy response. Moreover, under the pressure of CAR-T cell therapy, the tumor heterogeneity and tumor plasticity drive tumor evolution and therapy resistance, such as antigen escape. Nonetheless, scientists strive for strategies to overcome these hurdles, including novel CAR-T cell designs and regional delivery. For instance, the structure of multi-antigen-targeted CAR-T cells can enrich CAR-T accumulation in tumor TME and eliminate abundant tumor cells to avoid tumor antigen heterogeneity. Additionally, paired with an immune modifier and one or more stimulating domains, different generation of innovations in the structure and manufacturing of CAR-T cells have improved efficacy and persistence. While single CAR-T cell therapy receives limited clinical survival benefit. Compared with single CAR-T cell therapy, the combination therapies have supplemented the treatment paradigm. Combinatorial treatment methods consolidate the CAR-T cells efficacy by regulating the tumor microenvironment, optimizing the CAR structure, targeting the CAR-T cells to the tumor cells, reversing the tumor-immune escape mechanisms, and represent a promising avenue against GBM, based on multiple impressive research. Moreover, exciting results are also reported to be realized through combining effective therapies with CAR-T cells in preclinical and clinical trials samples, have aroused inspiration to explore the antitumor function of combination therapies. In summary, this study aims to summarize the limitation of CAR-T cell therapies and introduces novel strategies to enhance CAR-T cell function as well as prospect the potential of the therapeutic combination.

B7-H3-targeted CAR T cell activity is enhanced by radiotherapy in solid cancers

Adoptive cell therapy utilizing T cells genetically modified to express a chimeric antigen receptor (CAR) has demonstrated promising clinical results in hematological malignancies. However, solid cancers have not seen a similar success due to multiple obstacles. Investigating these escape mechanisms and designing strategies to counteract such limitations is crucial and timely. Growing evidence in the literature supports the hypothesis that radiotherapy has the potential to enhance the susceptibility of solid tumors to CAR T cell therapy, by overcoming mechanisms of resistance. Radiation treatment can increase the susceptibility of different types of solid cancers (TNBC, HNSCC, PDAC) to B7-H3 CAR T cell-mediated eradication. Multiple mechanisms, including reduced cancer cell proliferation, upregulation of the targeted antigen, modulation of apoptotic molecules may contribute to this signal. The information in the literature and the results we describesupport the ability of radiotherapy to improve the efficacy of CAR T cell therapy in solid tumors.

Recent advances and future perspectives of CAR-T cell therapy in head and neck cancer

Head and neck cancer (HNC) ranks as the sixth most prevalent type of cancer globally and accounts for about 4% of all types of cancer. Among all HNC, most are head and neck squamous cell carcinoma (HNSCC) with clinical therapies that include surgery, radiation therapy, chemotherapy, immunotherapy, targeted therapy, and multimodal treatments. In recent years, chimeric antigen receptor (CAR)-T cell immunotherapy has significantly transformed the therapeutic approaches for leukemia and lymphoma and has garnered increased attention as a potential treatment for a wide range of cancers. However, CAR-T immunotherapy in solid tumors, especially HNSCCs, lags significantly behind due to the paucity of tumor-specific antigens, high levels of tumor heterogeneity, immunosuppressive tumor microenvironment, the risk of treatment-related toxicities and off-target adverse events in HNSCCs. The objective of this review is to explore the advancement of CAR-T cell therapy in the treatment of HNSCCs. We aim to outline the targeted antigens in HNSCCs, highlight the challenges and potential solutions, and discuss the relevant combination therapies. Our review presents a comprehensive overview of the recent developments in CAR-T cell therapy for HNSCCs, and provides valuable insights into future research avenues.

Advancing cellular immunotherapy with macrophages

Cell-based immunotherapies have become an exciting avenue for cancer treatment, particularly CAR T cells, which have shown great success in treating hematological malignancies. However, the limited success of T cell-based approaches in treating solid tumors has sparked interest in alternative cell types that could be used for solid tumor immunotherapy. Recent research has pointed to macrophages as a potential solution, given their ability to infiltrate solid tumors, exhibit a strong anti-tumor response, and persist long-term in the tumor microenvironment. Although early attempts with ex-vivo activated macrophage-based therapies failed to translate into clinical success, the field has revolutionized with the recent development of chimeric antigen receptor-expressing macrophages (CAR-M). While CAR-M therapy has reached the clinical trial stage, several challenges still need to be overcome before the therapy can become a reality. Here we review the evolution of macrophage-based cell therapy and evaluate recent studies and developments, emphasizing the potential of macrophages as cellular therapeutics. Furthermore, we also discuss the challenges and opportunities associated with using macrophages as a basis for therapeutic interventions.

The role of tumor-infiltrating lymphocytes in triple-negative breast cancer and the research progress of adoptive cell therapy

The treatment outcome of breast cancer is closely related to estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression. Triple-negative breast cancer (TNBC) lacking ER, PR, and HER2 expression has limited treatment options and a poor prognosis. Tumor-infiltrating lymphocytes (TILs) play a role in promoting or resisting tumors by affecting the tumor microenvironment and are known as key regulators in breast cancer progression. However, treatments for TNBC (e.g., surgery, chemotherapy and radiotherapy) have non-satisfaction's curative effect so far. This article reviews the role of different types of TILs in TNBC and the research progress of adoptive cell therapy, aiming to provide new therapeutic approaches for TNBC.

CAR T-Cell Therapy in Children with Solid Tumors

The limited efficacy of traditional cancer treatments, including chemotherapy, radiotherapy, and surgery, emphasize the significance of employing innovative methods. CAR (Chimeric Antigen Receptor) T-cell therapy remains the most revolutionizing treatment of pediatric hematological malignancies and solid tumors. Patient’s own lymphocytes are modified ex-vivo using gene transfer techniques and programmed to recognize and destroy specific tumor cells regardless of MHC receptor, which probably makes CAR-T the most personalized therapy for the patient. With continued refinement and optimization, CAR-T cell therapy has the potential to significantly improve outcomes and quality of life for children with limited treatment options. It has shown remarkable success in treating hematological malignancies, such as acute lymphoblastic leukemia (ALL) and non-Hodgkin lymphoma (NHL). However, its effectiveness in treating solid tumors is still being investigated and remains an area of active research. In this review we focus on solid tumors and explain the concept of CAR modified T cells, and discuss some novel CAR designs that are being considered to enhance the safety of CAR T-cell therapy in under-mentioned cancers. Furthermore, we summarize the most crucial recent reports concerning the solid tumors treatment in children. In the end we provide a short summary of many challenges that limit the therapeutic efficacy of CAR-T in solid tumors, such as antigen escape, immunosuppressive microenvironment, poor trafficking, and tumor infiltration, on-target off-tumor effects and general toxicity.

The current landscape of CAR T-cell therapy for solid tumors: Mechanisms, research progress, challenges, and counterstrategies

The successful outcomes of chimeric antigen receptor (CAR) T-cell therapy in treating hematologic cancers have increased the previously unprecedented excitement to use this innovative approach in treating various forms of human cancers. Although researchers have put a lot of work into maximizing the effectiveness of these cells in the context of solid tumors, few studies have discussed challenges and potential strategies to overcome them. Restricted trafficking and infiltration into the tumor site, hypoxic and immunosuppressive tumor microenvironment (TME), antigen escape and heterogeneity, CAR T-cell exhaustion, and severe life-threatening toxicities are a few of the major obstacles facing CAR T-cells. CAR designs will need to go beyond the traditional architectures in order to get over these limitations and broaden their applicability to a larger range of malignancies. To enhance the safety, effectiveness, and applicability of this treatment modality, researchers are addressing the present challenges with a wide variety of engineering strategies as well as integrating several therapeutic tactics. In this study, we reviewed the antigens that CAR T-cells have been clinically trained to recognize, as well as counterstrategies to overcome the limitations of CAR T-cell therapy, such as recent advances in CAR T-cell engineering and the use of several therapies in combination to optimize their clinical efficacy in solid tumors.