'Off-the-shelf' allogeneic CAR T cells: development and challenges

Discovery of a pan anti-SARS-CoV-2 monoclonal antibody with highly efficient infected cell killing capacity for novel immunotherapeutic approaches

Unlocking the potential of broadly reactive coronavirus monoclonal antibodies (mAbs) and their derivatives offers a transformative therapeutic avenue against severe COVID-19, especially crucial for safeguarding high-risk populations. Novel mAb-based immunotherapies may help address the reduced efficacy of current vaccines and neutralizing mAbs caused by the emergence of variants of concern (VOCs). Using phage display technology, we discovered a pan-SARS-CoV-2 mAb (C10) that targets a conserved region within the receptor-binding domain (RBD) of the virus. Noteworthy, C10 demonstrates exceptional efficacy in recognizing all assessed VOCs, including recent Omicron variants. While C10 lacks direct neutralization capacity, it efficiently binds to infected lung epithelial cells and induces their lysis via natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity (ADCC). Building upon this pan-SARS-CoV-2 mAb, we engineered C10-based, Chimeric Antigen Receptor (CAR)-T cells endowed with efficient killing capacity against SARS-CoV-2-infected lung epithelial cells. Notably, NK and CAR-T-cell mediated killing of lung infected cells effectively reduces viral titers. These findings highlight the potential of non-neutralizing mAbs in providing immune protection against emerging infectious diseases. Our work reveals a pan-SARS-CoV-2 mAb effective in targeting infected cells and demonstrates the proof-of-concept for the potential application of CAR-T cell therapy in combating SARS-CoV-2 infections. Furthermore, it holds promise for the development of innovative antibody-based and cell-based therapeutic strategies against severe COVID-19 by expanding the array of therapeutic options available for high-risk populations.Trial registration: ClinicalTrials.gov identifier: NCT04093596.

Next-Generation CAR-T and TCR-T Cell Therapies for Solid Tumors: Innovations, Challenges, and Global Development Trends

Chimeric antigen receptor (CAR)-T and T-cell receptor (TCR)-engineered T-cell (TCR-T) therapies have revolutionized the treatment of hematological malignancies; however, their application to solid tumors remains a formidable challenge. The immunosuppressive tumor microenvironment, antigen heterogeneity, and manufacturing complexity limit the clinical efficacy and scalability of these treatment modalities. This review provides a comprehensive analysis of the current clinical development strategies for CAR-T and TCR-T cell therapies for solid tumors. Herein, we discuss recent breakthroughs and highlight the potential of TCR-T cell therapy. Furthermore, innovative approaches for enhancing CAR-T cell function in solid tumors (e.g., in vivo engineering; induced pluripotent stem cell-derived allogeneic CAR-T cells; armored CAR constructs; dual-antigen targeting; and combination regimens with checkpoint inhibitors, chemotherapy, radiotherapy, and oncolytic viruses) are explored. We also present trends in global patent activity, revealing a marked acceleration in CAR-T- and TCR-T-related innovations, with the United States and China leading with respect to application volumes. This field is increasingly characterized by multidisciplinary collaborations between academia and industry, driving the development of next-generation platforms, including messenger RNA-based and off-the-shelf cell therapies. Although no CAR-T product has been approved for solid tumors, these findings underscore the accelerating momentum and translational promise of adoptive cell therapies. Addressing the unique biological and logistical challenges of solid tumors is essential for realizing the full potential of these transformative immunotherapies.

Cell-Based Therapies for Solid Tumors: Challenges and Advances

Solid tumors pose significant therapeutic challenges due to their resistance to conventional treatments and the complexity of the tumor microenvironment. Cell-based immunotherapies offer a promising approach, enabling precise, personalized treatment through immune system modulation. This review explores several emerging cellular therapies for solid tumors, including tumor-infiltrating lymphocytes, T cell receptor-engineered T cells, CAR T cells, CAR natural killer cells, and macrophages. Tumor-infiltrating lymphocytes and their modified versions, T cell receptor-engineered T cells and CAR T cells, provide personalized immune responses, although their effectiveness can be limited by factors like variation in tumor antigens and the suppressive nature of the tumor environment. Natural killer cells engineered with chimeric receptors offer safer, non-major histocompatibility complex-restricted targeting, while modified macrophages exploit their natural ability to enter tumors and reshape the immune landscape. CAR-modified macrophages and macrophages conjugated with drugs are also considered as therapy for solid tumors. The review also examines the implications of autologous versus allogeneic cell sources. Autologous therapies ensure immunologic compatibility but are limited by scalability and manufacturing constraints. Allogeneic approaches offer "off-the-shelf" potential but require gene editing to avoid immune rejection. Integrating synthetic biology, gene editing, and combinatorial strategies will be essential to enhance efficacy and expand the clinical utility of cellular immunotherapies for solid tumors.

Non-viral, high throughput genetic engineering of primary immune cells using nanostraw-mediated transfection

Transfection of proteins, mRNA, and chimeric antigen receptor (CAR) transgenes into immune cells remains a critical bottleneck in cell manufacturing. Current methods, such as viruses and bulk electroporation, are hampered by low transfection efficiency, unintended transgene integration, and significant cell perturbation. The Nanostraw Electro-actuated Transfection (NExT) technology offers a solution by using high aspect-ratio nanostraws and localized electric fields to precisely deliver biomolecules into cells with minimal disruption. We demonstrate that NExT can deliver proteins, polysaccharides, and mRNA into primary human CD8+ and CD4+ T cells, and achieve CRISPR/Cas9 gene knockout of CXCR4 and TRAC in CD8+ T cells. We showcase NExT's versatility across a range of primary human immune cells, including CD4+ T cells, γδ-T cells, dendritic cells, NK cells, Treg cells, macrophages, and neutrophils. Finally, we developed a scalable, high-throughput multiwell NExT system capable of transfecting over 14 million cells and delivering diverse cargoes into multiple cell types from various donors simultaneously. This technology holds promise for streamlining high-throughput screening of allogeneic donors and reducing optimization costs for large-scale CAR-immune cell transfection.

Skin-Resident γδ T Cells Mediate Potent and Selective Antitumor Cytotoxicity through Directed Chemotactic Migration and Mobilization of Cytotoxic Granules

Dendritic epidermal T cells (DETCs) are a unique subset of γδ T cells that reside predominantly in mouse epidermis; yet, their antitumor functions remain enigmatic. In this study, we report that DETCs mediate potent and exquisitely selective cytotoxicity against diverse tumor types while sparing healthy cells. In vitro, DETCs induced apoptosis in melanoma, hepatoma, colon carcinoma, and lymphoma lines in a dose- and time-dependent manner that required direct cell-cell contact. In vivo, adoptive DETC transfer significantly suppressed melanoma growth and metastasis while prolonging survival. Mechanistically, DETCs upregulated perforin/granzyme B expression upon tumor recognition, and inhibition of this pathway ablated cytotoxicity. DETCs selectively homed to and formed intimate contacts with tumor cells in vivo through directed chemotaxis and aggregation. Tumor engagement triggered proinflammatory DETC activation while dampening immunosuppressive factors in the microenvironment. Notably, mTOR signaling coupled tumor recognition to DETC trafficking, cytotoxicity, and inflammatory programs because rapamycin treatment impaired effector functions and therapeutic efficacy. Collectively, these findings establish DETCs as multidimensional antitumor effectors and provide insights for harnessing their unique biology for cancer immunotherapy.

Harnessing the potential of gene-editing technology to overcome the current bottlenecks of CAR-T cell therapy in T-cell malignancies

T-cell malignancies (TCMs) include a diverse spectrum of hematologic cancers marked by complex biology and aggressive nature. Treating TCMs remains a critical unmet need in oncology with poor response to standard therapies. Chimeric antigen receptor (CAR)-T cell therapy is one of the most successful types of immunotherapy that has revolutionized cancer treatment, as evidenced by various approved products for CD19 B-cell malignancies and multiple myeloma. Nonetheless, due to some unique hurdles, such as the risk of CAR-T cell fratricide, product contamination with malignant cells, and severe T-cell aplasia, the translation of this treatment approach to TCMs has not been particularly successful. Moreover, irrespective of the type of treated cancer, CAR-T cell therapy can also present some complexities and potential side effects, such as cumbersome and costly manufacturing processes, impaired in vivo function, cytokine release syndrome (CRS), neurotoxicity, and leukemic transformation of CAR-T cells. Recent groundbreaking advances in gene-editing technology and the evolution of precise gene-editing tools such as the CRISPR/Cas9 system and its derivatives have opened a new way to overcoming the mentioned bottlenecks and paving the way for CAR-T cell therapy in TCMs. This review sheds light on how gene editing is being incorporated into CAR-T cell therapy to address current hurdles, enhance therapeutic efficacy, and improve the safety profile of CAR-T cell therapy in TCMs. Ongoing/conducted clinical trials are also discussed to provide a comprehensive view of the evolving landscape of genome-edited CAR-T cell therapy for TCMs.

Quadruple adenine base-edited allogeneic CAR T cells outperform CRISPR/Cas9 nuclease-engineered T cells

Genome-editing technologies have enabled the clinical development of allogeneic cellular therapies, yet the optimal gene-editing modality for multiplex editing of therapeutic T cell product manufacturing remains elusive. In this study, we conducted a comprehensive comparison of CRISPR/Cas9 nuclease and adenine base editor (ABE) technologies in generating allogeneic chimeric antigen receptor (CAR) T cells, utilizing extensive in vitro and in vivo analyses. Both methods achieved high editing efficiencies across four target genes, critical for mitigating graft-versus-host disease and allograft rejection: TRAC or CD3E, B2M, CIITA, and PVR. Notably, ABE demonstrated higher manufacturing yields and distinct off-target profiles compared to Cas9, with translocations observed exclusively in Cas9-edited products. Functionally, ABE-edited CAR T cells exhibited superior in vitro effector functions under continuous antigen stimulation, including enhanced proliferative capacity and increased surface CAR expression. Transcriptomic analysis revealed that ABE editing resulted in reduced activation of p53 and DNA damage response pathways at baseline, along with sustained activation of metabolic pathways during antigen stress. Consistently, Assay for Transposase-Accessible Chromatin using sequencing data indicated that Cas9-edited, but not ABE-edited, CAR T cells showed enrichment of chromatin accessibility peaks associated with double-strand break repair and DNA damage response pathways. In a preclinical leukemia model, ABE-edited CAR T cells demonstrated improved tumor control and extended overall survival compared to their Cas9-edited counterparts. Collectively, these findings position ABE as superior to Cas9 nucleases for multiplex gene editing of therapeutic T cells.

Next-generation immunotherapeutic approaches for blood cancers: Exploring the efficacy of CAR-T and cancer vaccines

Recent advancements in immunotherapy, particularly Chimeric antigen receptor (CAR)-T cell therapy and cancer vaccines, have significantly transformed the treatment landscape for leukemia. CAR-T cell therapy, initially promising in hematologic cancers, faces notable obstacles in solid tumors due to the complex and immunosuppressive tumor microenvironment. Challenges include the heterogeneous immune profiles of tumors, variability in antigen expression, difficulties in therapeutic delivery, T cell exhaustion, and reduced cytotoxic activity at the tumor site. Additionally, the physical barriers within tumors and the immunological camouflage used by cancer cells further complicate treatment efficacy. To overcome these hurdles, ongoing research explores the synergistic potential of combining CAR-T cell therapy with cancer vaccines and other therapeutic strategies such as checkpoint inhibitors and cytokine therapy. This review describes the various immunotherapeutic approaches targeting leukemia, emphasizing the roles and interplay of cancer vaccines and CAR-T cell therapy. In addition, by discussing how these therapies individually and collectively contribute to tumor regression, this article aims to highlight innovative treatment paradigms that could enhance clinical outcomes for leukemia patients. This integrative approach promises to pave the way for more effective and durable treatment strategies in the oncology field. These combined immunotherapeutic strategies hold great promise for achieving more complete and lasting remissions in leukemia patients. Future research should prioritize optimizing treatment sequencing, personalizing therapeutic combinations based on individual patient and tumor characteristics, and developing novel strategies to enhance T cell persistence and function within the tumor microenvironment. Ultimately, these efforts will advance the development of more effective and less toxic immunotherapeutic interventions, offering new hope for patients battling this challenging disease.

In vivo CAR engineering for immunotherapy

Chimeric antigen receptor (CAR)-engineered immune cell therapy represents an important advance in cancer treatments. However, the complex ex vivo cell manufacturing process and stringent patient selection criteria curtail its widespread use. In vivo CAR engineering is emerging as a promising off-the-shelf therapy, providing advantages such as streamlined production, elimination of patient-specific manufacturing, reduced costs and simplified logistics. A large set of preclinical findings has inspired further investigation into treatments for hard-to-treat diseases such as solid tumours and has facilitated the development of advanced products to enhance in vivo CAR engineering efficacy, the persistence of the cellular therapeutic and safety. In this Review, we summarize current in vivo CAR engineering strategies, including nanoparticle-based and viral delivery systems as well as bioinstructive implantable scaffolds, and discuss their advantages and disadvantages. Additionally, we provide a systematic comparison between in vivo and conventional ex vivo CAR engineering methods and address the challenges and future prospects of in vivo CAR engineering.

Exploiting regulatory T cells (Tregs): Cutting-edge therapy for autoimmune diseases

Regulatory T cells (Tregs) are a specialized subset of suppressive T cells that are essential for maintaining self-tolerance, regulating effector T cells, managing microbial infections, preventing tumors, allergies, and autoimmune disorders, and facilitating allograft transplantation. Disruptions in Treg function or abundance contribute to an imbalance between pathogenic and protective immune cells in autoimmune diseases. Recently, one promising treatment strategy to restore immune balance involves the selective expansion or manipulation of Tregs using low-dose IL-2 therapy, adoptive Treg cell transfer, and chimeric antigen receptor (CAR)-Treg approaches. Tregs have been shown in an increasing number of research studies to prevent or even treat a variety of disorders, such as tumors, autoimmune and allergic diseases, transplant rejection, and graft-versus-host disease. A thorough comprehension of Treg function is anticipated to provide clear prospects for effective Treg immunotherapy in the treatment of a wide range of diseases. This review provides an overview of Tregs biology, including their functions, suppressive mechanisms, phenotypic markers, as well as their involvement in disease settings. Furthermore, we discuss the therapeutic potential of different Treg subpopulations and their translational applications in the treatment of autoimmune diseases.

Harmonizing the Gut Microbiome and Cellular Immunotherapies: The Next Leap in Cancer Treatment

The gut microbiome, a diverse community of microorganisms, plays a key role in shaping the host's immune system and modulating cancer therapies. Emerging evidence highlights its critical influence on the efficacy and toxicity of cell-based immunotherapies, including chimeric antigen receptor T cell, natural killer cell, and stem cell therapies. This review explores the interplay between gut microbiota and cellular immunotherapies, focusing on mechanisms by which microbial metabolites and microbial composition impact treatment outcomes. Furthermore, we discuss strategies to leverage the gut microbiome to optimize therapeutic efficacy and minimize adverse effects. A deeper understanding of the relationship between the gut microbiome and cellular immunotherapies can pave the way for more effective cell-based therapies for cancer.

An Implantable Double-Layered Spherical Scaffold Depositing Gene and Cell Agents to Facilitate Collaborative Cancer Immunotherapy

Gene therapies and adoptive cell therapy (ACT) are promising strategies for cancer immunotherapy. Referring to their different mechanisms, the combination of these two might result in a strategy with potential collaborative and compensatory effects. However, it is challenging to combine gene therapies and ACT that work in a proper logical order. Here, we developed a double-layered spherical scaffold (DLS) to codeliver mRNA and T cells and constructed an implantable hydrogel formulation, named the GD-920 scaffold. With a diameter of 7 mm, this scaffold loaded primary T cells in the inner layer and the Bim mRNA nanocomplex in the outer layer. While maintaining their bioactivities, GD-920 released gene and cell payloads in a controllable and sequential manner. The mRNA complex from the outer layer was first released and induced immunogenic tumor cell death. The produced antigens then migrated into the scaffold with dendritic cells, triggering a tumor-specific immune response. Finally, activated T cells released by the inner layer attacked the tumor tissue via massive infiltration. We showed that in situ implantation of the GD-920 scaffold is capable of effectively inhibiting tumor growth and is far more potent than that of control scaffolds containing a single payload. Our results demonstrated the outstanding potential of this DLS in combining gene and cell therapeutic approaches to cancer immunotherapy.

A comprehensive analysis of induced pluripotent stem cell (iPSC) production and applications

The ability to reprogram mature, differentiated cells into induced pluripotent stem cells (iPSCs) using exogenous pluripotency factors opened up unprecedented opportunities for their application in biomedicine. iPSCs are already successfully used in cell and regenerative therapy, as various drug discovery platforms and for in vitro disease modeling. However, even though already 20 years have passed since their discovery, the production of iPSC-based therapies is still associated with a number of hurdles due to low reprogramming efficiency, the complexity of accurate characterization of the resulting colonies, and the concerns associated with the safety of this approach. However, significant progress in many areas of molecular biology facilitated the production, characterization, and thorough assessment of the safety profile of iPSCs. The number of iPSC-based studies has been steadily increasing in recent years, leading to the accumulation of significant knowledge in this area. In this review, we aimed to provide a comprehensive analysis of methods used for reprogramming and subsequent characterization of iPSCs, discussed barriers towards achieving these goals, and various approaches to improve the efficiency of reprogramming of different cell populations. In addition, we focused on the analysis of iPSC application in preclinical and clinical studies. The accumulated breadth of data helps to draw conclusions about the future of this technology in biomedicine.

Redefining quality in cell and gene therapies: Lessons from implementing electronic QMS in academic cGMP facility

Manufacturing cell and gene therapies (CGTs) involves complex processes that require robust quality management, especially within academic current Good Manufacturing Practice (cGMP) facilities, where resources are often limited. Traditional paper-based quality management systems (QMSs), while initially convenient, often become burdensome, leading to errors, poor traceability, and compliance risks. Electronic QMSs (eQMSs) are gaining recognition for their ability to centralize and automate key quality processes, significantly enhancing operational efficiency and regulatory readiness. Through an in-depth case study of the University of Southern California and Children's Hospital of Los Angeles academic cGMP facility, this review demonstrates tangible improvements achieved by adopting an eQMS. Practical insights gained from this experience are shared, including careful selection of eQMS platforms, phased rollout strategies, and comprehensive staff training. The review also addresses common implementation challenges and suggests practical solutions to overcome them. Lessons learned and strategies discussed here can serve as valuable guidance for other academic institutions considering eQMS adoption. Ultimately, embracing an eQMS enables academic CGT manufacturers to operate more efficiently and stay ahead in a fast-moving field.

Emerging trends in clinical allogeneic CAR cell therapy

There has been significant progress in the clinical development of allogeneic off-the-shelf chimeric antigen receptor (CAR)-engineered cell therapies for the treatment of cancer and autoimmune diseases. Unlike autologous CAR cell therapies, allogeneic approaches overcome challenges such as high costs, labor-intensive manufacturing, and stringent patient selection. This makes allogeneic therapies a more universally applicable option for a diverse patient population. In this review, we examine recent clinical advancements in allogeneic CAR cell therapies, including CAR-T cell therapy derived from healthy donor peripheral blood mononuclear cells, as well as CAR-NK cell therapy from cord blood or induced pluripotent stem cells. We provide an overview of their genetic engineering strategies, clinical designs, and outcomes, highlighting their promising efficacy and safety. Additionally, we summarize key preclinical developments, address key challenges, and explore future directions to provide insights into emerging trends in the field.

FDA Experience on CAR T Cell Pharmacokinetics/Pharmacodynamics and Model-Based Assessments

Chimeric antigen receptor T cell (CAR T) therapies are genetically modified T cells that are engineered to recognize specific cell surface antigens (e.g., CD19 or B cell maturation antigen (BCMA), expressed on B cells). The objective of this review is to describe FDA experience with assessing the pharmacokinetics (PK), pharmacodynamics (PD) and conducting model-based analyses of FDA-approved CAR T cell products. The seven currently approved CAR T cell products target CD19 or BCMA and have both flat dose and body-weight-based intravenous dosing. The PK (e.g., expansion and persistence) and PD (e.g., B-cell aplasia, cytokine levels, and chemokine levels) data were an integral component of CAR T cell clinical pharmacology assessments. Model-based assessments, including population PK and exposure-response analysis, were conducted to understand PK variability and identify intrinsic/extrinsic factors impacting safety and efficacy outcomes. Continued use of clinical pharmacology tools such as model-based assessment to inform dose selection, dose optimization, and therapeutic individualization is integral to characterizing the effects of CAR T products.

Pathogenesis and Systemic Treatment of Hepatocellular Carcinoma: Current Status and Prospects

Hepatocellular carcinoma (HCC) remains one of the major threats to human health worldwide. The emergence of systemic therapeutic options has greatly improved the prognosis of patients with HCC, particularly those with advanced stages of the disease. In this review, we discussed the pathogenesis of HCC, genetic alterations associated with the development of HCC, and alterations in the tumor immune microenvironment. Then, important indicators and emerging technologies related to the diagnosis of HCC are summarized. Also, we reviewed the major advances in treatments for HCC, offering insights into future prospects for next-generation managements.

Addressing graft-versus-host disease in allogeneic cell-based immunotherapy for cancer

Allogeneic cell-based immunotherapies, particularly CAR-T cell therapy, represent a significant advancement in cancer treatment, offering scalable and consistent alternatives to autologous therapies. However, their widespread use is limited by the risk of graft-versus-host disease (GvHD). This review provides a comprehensive overview of GvHD in the context of allogeneic cell-based cancer immunotherapy and evaluates current strategies to mitigate its effects. Key strategies include genetic engineering approaches such as T cell receptor (TCR) knockout (KO) and T cell receptor alpha constant (TRAC) CAR knock-in. Alternative immune cell types like natural killer (NK) cells and natural killer T (NKT) cells offer potential solutions due to their lower alloreactivity. Additionally, stem cell technology, utilizing induced pluripotent stem cells (iPSCs), enables standardized and scalable production of engineered CAR-T cells. Clinical trials evaluating these strategies, such as UCART19 and CTX110, demonstrate promising results in preventing GvHD while maintaining anti-tumor efficacy. The review also addresses manufacturing considerations for allogeneic cell products and the challenges in translating preclinical findings into clinical success. By addressing these challenges, allogeneic cell-based immunotherapy continues to advance, paving the way for more accessible, scalable, and effective cancer treatments.

From Multi-Omics to Visualization and Beyond: Bridging Micro and Macro Insights in CAR-T Cell Therapy

Chimeric antigen receptor T (CAR-T) cell therapies, a cornerstone of immunotherapy, have demonstrated remarkable efficacy in treating hematological malignancies and have more recently expanded into applications for solid tumors and autoimmune diseases. Emerging multidimensional profiling technologies offer promising solutions for enhancing CAR-T efficacy, overcoming resistance, and facilitating the development of novel CAR-T constructs. The integration of genomics, epigenomics, transcriptomics, proteomics, metabolomics, and microbiomics enables a comprehensive understanding of the intrinsic mechanisms underlying CAR-T therapy, while single-cell and spatial omics significantly improve data resolution and analytical depth. Coupled with advances in biomedical engineering, visualization technologies form the foundation for omics data generation by bridging microscopic and macroscopic scales and enabling dynamic, 3D in vivo monitoring of CAR-T behavior. Artificial intelligence (AI) further supports this framework by enabling the analysis of complex, high-dimensional datasets. This review highlights recent advances in the integration of multidimensional omics within CAR-T therapy and explores cutting-edge developments in visualization technologies and AI applications. The full convergence of multi-omics, visualization tools, and AI is poised to deliver transformative insights into the mechanisms governing CAR-T cell therapy.

Generating allogeneic CAR-NKT cells for off-the-shelf cancer immunotherapy with genetically engineered HSP cells and feeder-free differentiation culture

The clinical potential of current chimeric antigen receptor-engineered T (CAR-T) cell therapy is hampered by its autologous nature that poses considerable challenges in manufacturing, costs and patient selection. This spurs demand for off-the-shelf therapies. Here we introduce an ex vivo feeder-free culture method to differentiate gene-engineered hematopoietic stem and progenitor (HSP) cells into allogeneic invariant natural killer T (AlloNKT) cells and their CAR-armed derivatives (AlloCAR-NKT cells). We include detailed information on lentivirus generation and titration, as well as the five stages of ex vivo culture required to generate AlloCAR-NKT cells, including HSP cell engineering, HSP cell expansion, NKT cell differentiation, NKT cell deep differentiation and NKT cell expansion. In addition, we describe procedures for evaluating the pharmacology, antitumor efficacy and mechanism of action of AlloCAR-NKT cells. It takes ~2 weeks to generate and titrate lentiviruses and ~6 weeks to generate mature AlloCAR-NKT cells. Competence with human stem cell and T cell culture, gene engineering and flow cytometry is required for optimal results.

CAR T-cell therapy landscape in pediatric, adolescent and young adult oncology - A comprehensive analysis of clinical trials

Chimeric Antigen Receptor (CAR) T-cell therapy has emerged as a transformative approach in cancer treatment, particularly for hematologic malignancies. This therapy involves the genetic modification of patients' T-cells to target specific tumor antigens, bypassing the traditional MHC-TCR-mediated recognition. This innovation marks a significant step toward personalized medicine and precision oncology. In the pediatric, adolescent, and young adult (P-AYA) populations, Tisagenlecleucel (Kymriah®) exemplifies the success of CAR T-cell therapy, demonstrating significant efficacy in treating relapsed or refractory acute lymphoblastic leukemia (r/r ALL). However, the development of CAR T-cell therapies for P-AYA patients has not progressed as rapidly as for adults, with only one FDA approval for pediatric applications compared to six for adults up to 2024. Several challenges hinder the development of pediatric CAR T-cell therapies, including complex production logistics, limited clinical site access, restrictive patient eligibility criteria, and financial constraints, necessitating more effective incentives for pediatric oncology drug development independent of adult indications. To assess the current landscape of CAR T-cell therapy in P-AYA oncology, we conducted a comprehensive review of clinical trials registered on ClinicalTrials.gov up to May 2024. Our analysis included 77 trials exclusively targeting the P-AYA population from an initial pool of 40,690 studies filtered by age, dates, and specific criteria related to CAR T-cell interventions in cancer therapy. We found that 45 % of these trials originated from the USA and 30 % from China. The data retrieved from these trials provided insights into various aspects, including histological categories, antigenic targets, CAR-T generations, costimulatory domains, manufacturing processes, geographical distribution, and funding sources. This review highlighted a predominant focus on hematologic malignancies, particularly B-cell acute lymphoblastic leukemia (B-ALL), with significant attention to dual antigen targeting (CD19 and CD22) to address resistance mechanisms. Emerging targets such as GD2 for solid tumors and B7-H3 for various cancers also showed promise. Additionally, most trials still utilize second-generation CAR-T constructs with 4-1BB costimulatory domains, reflecting a conservative approach in pediatric populations. Our findings underscore the disparity in CAR T-cell therapy development between pediatric and adult populations, driven by distinct biological, ethical, and economic considerations. Pediatric cancers require specialized treatments tailored to the unique biology and genetic makeup of pediatric oncology. However, research and drug development have historically focused less on pediatric needs. Despite legislative efforts to promote pediatric oncology drug development, significant gaps remain. Clinical trials for P-AYA populations face challenges in patient enrollment, trial design, and funding, often relying on academic and non-profit institutions. Addressing these barriers is critical for advancing CAR T-cell therapy in pediatric oncology, improving outcomes, and ensuring equitable access to innovative treatments for these vulnerable populations. This review aims to inform future research and policy decisions, promoting advancements in CAR T-cell therapy for P-AYA cancer patients.

Safety and feasibility of 4-1BB co-stimulated CD19-specific CAR-NK cell therapy in refractory/relapsed large B cell lymphoma: a phase 1 trial

Chimeric antigen receptor (CAR)-modified NK (CAR-NK) cells are candidates for next-generation cancer immunotherapies. Here we generated CD19-specific CAR-NK cells with 4-1BB and CD3ζ signaling endo-domains (CD19-BBz CAR-NK) by transduction of cord blood-derived NK cells using baboon envelope pseudotyped lentiviral vectors and demonstrated their antitumor activity in preclinical B cell lymphoma models in female mice. We next conducted a phase 1 dose-escalation trial involving repetitive administration of CAR-NK cells in 8 patients with relapsed/refractory large B cell lymphoma (NCT05472558). Primary end points were safety, maximum tolerated dose, and overall response rate. Secondary end points included duration of response, overall survival, and progression-free survival. No dose-limiting toxicities occurred, and the maximum tolerated dose was not reached. No cases of cytokine release syndrome, neurotoxicity, or graft-versus-host disease were observed. Results showed an overall response rate of 62.5% at day 30, with 4 patients (50%) achieving complete response. The median progression-free survival was 9.5 months, and the median overall survival was not reached. A post hoc exploratory single-cell RNA sequencing analysis revealed molecular features of CAR-NK cells associated with therapeutic efficacy and efficacy-related immune cell interaction networks. This study met the pre-specified end points. In conclusion, CD19-BBz CAR-NK cells were feasible and therapeutically safe, capable of inducing durable response in patients with B cell lymphoma.

Immunotherapy Strategies After Immune Checkpoint Inhibitor Exposure in Renal Cell Carcinoma: A Review

Importance

Immune checkpoint inhibitors have transformed the treatment landscape for metastatic renal cell carcinoma; however, the failure of first-line therapeutic strategies remains a considerable challenge. Currently, clinicians face various issues, such as managing cases in patients who progress during treatment or relapse after adjuvant immunotherapy.

Observations

This review evaluates different strategies for treating patients with advanced kidney cancer previously exposed to immunotherapy. Evidence from other malignant neoplasms suggests potential effectiveness for rechallenging with immune checkpoint inhibitors. The most important available data are presented, including retrospective, prospective, and randomized clinical trials, to explore the role of immunotherapy in patients with renal cell carcinoma who have experienced prior failure of immune checkpoint inhibitors.

Conclusions and Relevance

Although retrospective data suggest modest effectiveness of an immunotherapy rechallenge treatment, larger phase 3 trials failed to demonstrate substantial benefit in progression-free survival and overall survival. Currently, no randomized evidence supports the use of agents targeting conventional immune checkpoints in patients with renal cell carcinoma who have previously received immunotherapy.

Advancing Allogeneic NK Cell Immunotherapy through Microfluidic Gene Delivery

Chimeric antigen receptor (CAR)-T cell therapy has revolutionized cancer treatment, yet challenges such as manufacturing complexity, high costs, and safety concerns have spurred the development of alternatives like CAR-natural killer (NK) cell immunotherapies. CAR-NK cell therapies provide innate cytotoxicity with antigen-independent targeting, reducing safety risks while improving therapeutic efficacy. However, efficient genomic engineering and large-scale production of allogeneic NK cells remain significant obstacles. To address these challenges, a novel microfluidic gene delivery platform is developed, the Y-hydroporator, designed for allogeneic NK cell immunotherapy. This platform features a Y-shaped microchannel where NK cells experience rapid hydrodynamic stretching near the stagnation point, creating transient membrane discontinuities that facilitate the uptake of exogenous cargo. The Y-hydroporator achieves high delivery and transfection efficiency, processing ≈2 × 106 cells min-1 while maintaining long-term cell viability (>89%) and functionality. Using this platform, human primary CAR-NK cells and NKG2A-knockout NK cells are successfully generated by delivering anti-CD19 CAR mRNA and CRISPR/Cas9 ribonucleoproteins, respectively. These engineered NK cells demonstrated enhanced cytotoxicity, underscoring the potential of the Y-hydroporator as a transformative tool for advancing allogeneic NK cell-based immunotherapies.

m6A hypermethylation of TCF-1 regulated by METTL16 promotes acute myeloid leukemia

BACKGROUND

Methyltransferase 16 (METTL16) functions as an oncogene in various cancer, including leukemia. However, the role of METTL16 in acute myeloid leukemia (AML) is scarcely reported. The present study aimed to investigate the potential of METTL16 in AML.

METHODS

RT-qPCR was used to METTL16 expression in AML patients and healthy control. m6A levels was determined using m6A assay. Methylated RNA immunoprecipitation (MeRIP) assay applied for determining m6A hypermethylation of T cell factor 1 (TCF-1) transcripts in AML cells. Chimeric antigen receptor (CAR)-T-cell functions were analyzed using flow cytometry.

RESULTS

METTL16 is upregulated in AML patients. High levels of METTL16 were associated with poor prognosis of AML patients. Functionally, METTL16 deficiency promoted the persistence and tumor-killing ability of CAR-T cells. Moreover, METTL16 deficiency promoted the differentiation of CAR-T cells into TCF-1 precursor exhausted T cells (TPEX). METTL16 mediated the m6A modification of TCF-1 and inhibited its mRNA expression and stability. TCF-1 deficiency promoted the exhaustion and inhibited the self-renewal ability of T cells.

CONCLUSION

Collectively, METTL16 deficiency promoted the persistence of CAR-T cells and memory formation in AML. Therefore, targeting METTL16 may stimulate the anti-tumor immunity in AML.

Revolutionizing immunotherapy: The next frontier in CAR T-cell engineering

Chimeric Antigen Receptor (CAR) T-cell therapy has emerged as a groundbreaking immunotherapy, offering new hope for cancer treatment, particularly in hematologic malignancies. This review explores the development of CAR T-cell therapy from its first-generation design, which laid the foundational structure, to advanced fifth-generation CARs that integrate sophisticated synthetic biology. Each generation of CARs has introduced critical improvements, such as the incorporation of costimulatory domains, dual signaling pathways, and cytokine release mechanisms to enhance T-cell activation, persistence, and efficacy. Current applications of CAR T-cell therapy have seen significant success in treating cancers like acute lymphoblastic leukemia and diffuse large B-cell lymphoma, with several therapies gaining regulatory approval. However, challenges persist in targeting solid tumors due to the immunosuppressive tumor microenvironment and antigen heterogeneity. Ongoing clinical trials and research are focused on overcoming these barriers through next-generation CAR designs, novel antigen targets, and combination therapies. The review highlights recent advancements, emerging targets, and the potential of CAR T-cell therapy to revolutionize cancer treatment, paving the way for more effective and personalized approaches.

CAR-T cell therapy in rheumatic diseases: a review article

CAR-T cell therapy, a pioneering immune-modulating treatment that was initially designed for hematologic malignancies, is now being considered a potential treatment for autoimmune and rheumatic diseases. This method involves genetically engineering T cells to express chimeric antigen receptors (CARs), allowing them to target specific antigens associated with pathogenic immune cells. The review covers the possibility of CAR-T therapy in the treatment of autoimmune diseases like systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc). The therapy's ability to maintain remission by targeting autoreactive B cells in the course of disease has been an important aspect of studies involving SLE. In refractory RA, CAR-T cells also demonstrate a potential therapeutic modality in selectively killing immune cells driving the disease process. For SSc, CAR-T therapy may represent a novel therapeutic approach because it targets the dysregulated activity of B cells as well as the fibrotic processes that drive the disease pathology. Emerging evidence suggests potential applications in conditions such as Sjögren's syndrome and dermatomyositis. While CAR-T therapy promises accuracy, persistence, and the potential for long-term remission, many problems remain, including the risk of cytokine release syndrome, immune toxicity, and treatment affordability. The development of CAR-Tregs and advanced gene-editing techniques may increase the specificity and safety of therapy. In addition, clinical trials and long-term studies should be conducted to establish the efficacy, safety, and economic feasibility of this innovative approach. This review underscores the transformative potential of CAR-T therapy in the management of rheumatic diseases, particularly in refractory cases. Offering targeted immunomodulation with a minimum of systemic immune suppression, CAR-T therapy could redefine therapeutic paradigms and offer hope for improved outcomes in autoimmune diseases.

MUC18-Directed chimeric antigen receptor T cells for the treatment of mucosal melanoma

PURPOSE

Mucosal melanoma, a highly aggressive form of skin cancer, remains challenging to manage due to the lack of effective therapies. Mucin 18 (MUC18) is overexpressed in both primary and metastatic lesions of melanoma but rarely in normal tissues. The expression profile makes MUC18 a potential target for development of therapeutic antibodies or chimeric antigen receptor-T (CAR-T) cell therapy. This study aims to generate an effective CAR-T targeting MUC18-positive melanoma and evaluate its preclinical antitumor activity.

EXPERIMENTAL DESIGN

A humanized anti-MUC18 single chain antibody fragment (scFv) was used to construct CAR-T with various designs of the hinge, transmembrane, co-stimulatory, and CD3ζ domains. The antitumor efficacy of MUC18 CAR-T cells was assessed in vitro, in MUC18-positive primary and rechallenged xenograft models, as well as in patient-derived xenograft (PDX) models of human mucosal melanoma.

RESULTS

The humanized scFv selectively bound to MUC18 with high affinity. Various MUC18 CAR-T cells specifically killed MUC18-positive melanoma cells and could proliferate as a result of exposure to antigen. Among them, CAR-T cells containing an IgG4-derived hinge domain and a CD28 co-stimulatory domain demonstrated superior antitumor efficiency. Robust tumor regression and CAR-T cell expansion were observed in multiple MUC18-positive xenograft models after treatment with the IgG4 hinge and CD28 empowered CAR-T cells.

CONCLUSIONS

This study demonstrated the development of a novel CAR-T therapy for mucosal melanoma, MUC18 CAR-T, that showed strong potency in tumor eradication and inhibition of tumor relapse. This candidate CAR-T therapy could provide a promising strategy for the treatment of the refractory melanoma.

HHV-6 and HHV-7 reactivation in allogeneic CAR-T cell therapy

Autologous chimeric antigen receptor (CAR)-T cell therapy has revolutionized cancer treatment and allogeneic CAR-T cell therapy is poised to advance this revolution. CAR-T cell therapy faces some concerns regarding adventitious agents, which can threaten the safety of patients. Human herpesviruses 6 and 7 (HHV-6 and HHV-7) have become increasingly notable in this context, as they carry a risk with severe health consequences. This review explores these virus reactivations in CAR-T cell therapy and discusses mitigation strategies during allogeneic CAR-T cell manufacturing. We provide an overview of prevention and testing strategies, genetic engineering applications, and chemical substances with potential for interventions. This review aims to enhance understanding of HHV reactivation and improve the safety of allogeneic CAR-T cell therapies.

The present and future of CAR T-cell therapy for adult B-cell ALL

ABSTRACT

Chimeric antigen receptor T-cell therapy (CAR-T) targeting CD19 has transformed the management of relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL), with the US Food and Drug Administration approval of tisagenlecleucel for pediatric/young adult patients and brexucabtagene autoleucel for adults. Efficacy is contingent upon several factors including disease burden. Emerging data suggest that bridging therapy, lymphodepletion, and, for some patients, consolidation therapy have an important role in the success of treatment. Furthermore, strategies to define and manage immunotoxic side effects including hematotoxicity is critical to safe delivery. Advancements in CAR-T design beyond CD19 represent an ongoing therapeutic evolution. Overall, CAR-T signifies a paradigm shift in B-ALL management, with the potential for improved remission and survival in a historically challenging patient population.

Turning "trashed" genomic loci into treasurable sites for integrating chimeric antigen receptors in T and NK cells

Chimeric antigen receptor (CAR)-based immune cell therapy involves genetically engineering immune cells, such as T cells and natural killer (NK) cells, to express CARs that can specifically recognize target antigens. This modification enables T/NK cells to selectively eliminate tumor cells following adoptive transfer. One common approach to stably integrate CARs into the genome of T/NK cells is through retroviral or lentiviral vectors. However, these vectors mediate semi-random gene integration, posing risks such as oncogenic mutations, gene silencing, and variable CAR expression levels. Targeted integration of CAR genes into the specific genomic locus could overcome these limitations, but identifying the optimal integration sites to maximize the safety and efficacy of CAR-T/NK cell products remains a critical question. Improper integration sites may disturb the endogenous genes surrounding the integration sites, raising safety concerns. Additionally, regulatory elements at the integration sites, such as promoters, can influence the expression level of CAR genes, thus affecting the efficacy of CAR-T/NK cells. In this review, we summarized current strategies for selecting integration sites and promoters in the engineering of CAR-T/NK cells to achieve potent anti-tumor efficacy in preclinical studies.

Dasatinib-resistant universal CAR-T cells proliferate in the presence of host immune cells and exhibit antitumor activity

The universal chimeric antigen receptor T cell (UCAR-T) immunotherapy derived from healthy donors holds great promise in pan-cancer treatment. However, UCAR-T cell therapy faces a challenge in the rapid elimination of allogeneic cells by the host immune system. To address this, we introduced a T316I mutation in the leukocyte-specific protein tyrosine kinase (LCK) locus in CAR-T cells using the cytosine base editor (CBE) system. Concurrently, we disrupted endogenous T cell receptor alpha chain (TRAC) and beta-2 microglobulin (B2M) with the CRISPR-Cas9 system, along with dasatinib to overcome host immune rejection, an Src family kinase (SFK) inhibitor. The resulting LCK mutated UCAR-T (KM UCAR-T) cells exhibited normal phenotypes in activation, proliferation, differentiation, and tumor cytotoxicity in vitro. Moreover, KM UCAR-T cells demonstrated sustained expansion in mixed lymphocyte reactions (MLR) when incubated with T cells or peripheral blood mononuclear cells (PBMCs) from HLA-mismatched donors upon dasatinib treatment. Additionally, we illustrated that KM UCAR-T cells displayed antitumor activity in a xenograft murine model and verified the expansion and cytotoxicity of KM UCAR-T over traditional UCAR-T in the presence of allogeneic PBMCs when treated with dasatinib in vivo. These findings offer a novel strategy for UCAR-T cells to resist host immune rejection and achieve sustained expansion.

DHODH inhibition alters T cell metabolism limiting acute graft-versus-host disease while retaining graft-versus-leukemia response

Acute graft-versus-host disease (GVHD) is a donor T cell driven complication and the leading cause of non-relapse mortality in patients receiving an allogeneic hematopoietic cell transplantation (allo-HCT). Allogeneic donor T cells eradicate residual leukemia and prevent relapse via the graft-versus-leukemia (GVL) effect and are critical for responding against opportunistic infections post-transplant. Current regimens successful in preventing GVHD are broadly immunosuppressive and come at the cost of increased risk of relapse and/or infection. Therefore, there is an urgent need for new approaches that limit GVHD while retaining GVL responses. During GVHD, alloreactive T cells boost their energy production through oxidative phosphorylation (OXPHOS) and glycolysis, supporting heightened proliferation and pathogenicity against healthy host tissues. The enzyme dihydroorate dehydrogenase (DHODH), is essential for de novo pyrimidine biosynthesis and for maintaining mitochondrial membrane potential during OXPHOS. Having shown upregulation of DHODH messenger RNA and protein expression in activated human T cells, we evaluated DHODH inhibition, via a small molecule inhibitor HOSU-53, as a therapeutic approach for GVHD. Inhibiting DHODH significantly reduced oxidative metabolism in T cells both during and after activation, while selectively suppressing inflammatory cytokine production in de novo activated, but not previously activated, T cells. In a xenogeneic model, HOSU-53 treatment limited GVHD severity, decreased pathogenic Th1 and Th17 response, and preserved beneficial GVL effects. Altogether, we identify DHODH inhibition as an innovative treatment strategy in allo-HCT recipients to reduce GVHD severity and retain effective GVL response.

The role of γδ T cells in flavivirus infections: Insights into immune defense and therapeutic opportunities

γδ T cells are a unique subset of unconventional T cells and an important component of the innate immune system. Unlike conventional αβ T cells, γδ T cells can respond rapidly during the early stages of infection, and their antigen recognition is not restricted by MHC molecules. These distinctive features underscore the important role of γδ T cells in viral clearance and infection control. Therefore, γδ T cell-based immunotherapies have been extensively explored for the treatment of a variety of diseases, including viral infections and cancers. Several therapeutic strategies based on γδ T cells have advanced to clinical trials, demonstrating promising safety and efficacy. Currently, there are no effective treatments for flavivirus infections, which are typically characterized by acute onset. Research has shown that γδ T cells can rapidly expand during the early phases of flavivirus infections and effectively suppress viral replication, making them an attractive target for the development of novel therapies for flavivirus infections. This review aims to highlight the immunological roles of γδ T cells in flavivirus infections and to explore the potential of γδ T cell-based therapeutic strategies for the prevention and treatment of these infections.

Targeting cardiac fibrosis with Chimeric Antigen Receptor-Engineered Cells

Cardiac fibrosis poses a significant challenge in cardiovascular diseases due to its intricate pathogenesis, and there is currently no standardized and effective treatment approach. The fibrotic process entails the involvement of various cell types and molecular mechanisms, such as fibroblast activation and proliferation, increased collagen synthesis, and extracellular matrix rearrangement. Traditional therapies often fall short in efficacy or carry substantial side effects. However, recent studies have shown that Chimeric Antigen Receptor T (CAR-T) cells can selectively target and eliminate activated cardiac fibroblasts (CFs) in mice, leading to reduced cardiac fibrosis and improved myocardial tissue compliance. This breakthrough presents a new and promising avenue for treating cardiac fibrosis. Currently, CAR-T cell-based therapy for cardiac fibrosis is undergoing animal experimentation, indicating ample scope for enhancement. Future investigations could explore the application of CAR cell therapy in cardiac fibrosis treatment, including the potential of CAR-natural killer (CAR-NK) cells and CAR macrophages (CAR-M), offering novel insights and strategies for combating cardiac fibrosis.

Enrichment of CD4+ and CD8+ T lymphocytes with a column-free flow-based device for clinical cell manufacturing

In recent years, adoptive T cell-based immunotherapies have been developed to treat a wide range of hematologic malignancies, including relapsed or refractory non-Hodgkin lymphoma, B-cell leukemia, and multiple myeloma. Most of the commercially approved adoptive T cell therapies are composed of chimeric antigen receptor (CAR)-based T cells, which are a patient's own T cells engineered for recognition of a specific surface antigen, such as CD19 or CD20. Unselected peripheral blood mononuclear cells (PBMCs) have recently been used in several manufacturing protocols, but the vast majority of protocols still use CD4/CD8-selected T cells. The first step in manufacture of these CAR-T products involves simultaneous selection/purification of CD4+ and CD8+ (or CD4/CD8 positive) T cells. The typical approach for selection of CD4/CD8 subsets for clinical manufacturing involves immunomagnetic labeling followed by selection of positively labeled cells using static column-based approaches that are prone to cell clogging events and typically take approximately 2 to 3 hours in a closed system. Here, we used a new column-free, flow-based, fully closed system suitable for clinical cell manufacturing for isolation of CD4/CD8 cells with high purity in a rapid fashion that could accommodate varying capacities without compromising cell recovery. This new approach allows markedly faster cell selection, preserving the quality of the cells that are used for downstream CAR-T cell manufacture. We report the results of our successful validation runs using the new MARS Bar enrichment platform using human apheresis-derived leukocytes for CD4/CD8 isolation in a selection buffer or directly in T cell culture media for subsequent CAR-T cell production. Our data show a rapid and robust CD4/CD8 enrichment with an enrichment time shortened to 1 hour or less. Overall purity (based on CD3+ expression) of the cells was 95.51 ± 1.23% and 93.13 ± 0.30% for fresh and thawed T cells, respectively. Cell recoveries were 64.68 ± 14.05% and 57.06 ± 6.28% for fresh and thawed cells, respectively. We then further tested the MARS Bar enrichment platform after cell wash/volume reduction using the LOVO Automated Cell Processing System, leading to a higher consistency in CD3+ purity and increased cell recovery of 68.50 ± 3.54%. Enriched cells were characterized by high viability, ie. 90.5 ± 0.05% for fresh leukopaks when used together with the LOVO device. Altogether, the new approach using the MARS Bar platform allows one to customize and standardize the selection process by using a stand-alone instrument in a clinical manufacturing setting together with cGMP grade reagents and buffers.

The clinical landscape of CAR NK cells

Chimeric antigen receptor (CAR) NK cell therapy has emerged as a promising alternative to CAR T cell therapy, offering significant advantages in terms of safety and versatility. Here we explore the current clinical landscape of CAR NK cells, and their application in hematologic malignancies and solid cancers, as well as their potential for treating autoimmune disorders. Our analysis draws from data collected from 120 clinical trials focused on CAR NK cells, and presents insights into the demographics and characteristics of these studies. We further outline the specific targets and diseases under investigation, along with the major cell sources, genetic modifications, combination strategies, preconditioning- and dosing regimens, and manufacturing strategies being utilized. Initial results from 16 of these clinical trials demonstrate promising efficacy of CAR NK cells, particularly in B cell malignancies, where response rates are comparable to those seen with CAR T cells but with lower rates of severe adverse effects, such as cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and graft-versus-host disease (GvHD). However, challenges remain in solid tumor applications, where only modest efficacy has been observed to date. Our analysis reveals that research is increasingly focused on enhancing CAR NK cell persistence, broadening their therapeutic targets, and refining manufacturing processes to improve accessibility and scalability. With recent advancements in NK cell engineering and their increased clinical applications, CAR NK cells are predicted to become an integral component of next-generation immunotherapies, not only for cancer but potentially for immune-mediated diseases as well.

The role of B2M in cancer immunotherapy resistance: function, resistance mechanism, and reversal strategies

Immunotherapy has emerged as a preeminent force in the domain of cancer therapeutics and achieved remarkable breakthroughs. Nevertheless, the high resistance has become the most substantial impediment restricting its clinical efficacy. Beta-2 microglobulin (B2M), the light chain of major histocompatibility complex (MHC) class I, plays an indispensable part by presenting tumor antigens to cytotoxic T lymphocytes (CTLs) for exerting anti-tumor effects. Accumulating evidence indicates that B2M mutation/defect is one of the key mechanisms underlying tumor immunotherapy resistance. Therefore, elucidating the role played by B2M and devising effective strategies to battle against resistance are pressing issues. This review will systematically expound upon them, aiming to provide insight into the potential of B2M as a promising target in anticancer immune response.

New player in CAR-T manufacture field: comparison of umbilical cord to peripheral blood strategies

One of the most successful treatments in hematologic cancer is chimeric antigen receptor (CAR)-T cell-based immunotherapy. However, CAR-T therapy is not without challenges like the costly manufacturing process required to personalize each treatment for individual patients or graft-versus-host disease. Umbilical cord blood (UCB) has been most commonly used for hematopoietic cell transplant as it offers several advantages, including its rich source of hematopoietic stem cells, lower risk of graft-versus-host disease, and easier matching for recipients due to less stringent HLA requirements compared to bone marrow or peripheral blood stem cells. In this review, we have discussed the advantages and disadvantages of different CAR-T cell manufacturing strategies with the use of allogeneic and autologous peripheral blood cells. We compare them to the UCB approach and discuss ongoing pre-clinical and clinical trials in the field. Finally, we propose a cord blood bank as a readily available source of CAR-T cells.

Sodium citrate pretreatment enhances CAR-T cell persistence and anti-tumor efficacy through inhibition of calcium signaling

Introduction

Chimeric antigen receptor T cell (CAR-T) therapy has shown success in treating hematological malignancies, but its effectiveness against solid tumors is hindered by T cell exhaustion. During in vitro expansion, tonic signaling induced by CAR expression contributes to CAR-T cell exhaustion, which can be mitigated by inhibiting calcium signaling. Given that sodium citrate can chelate calcium ions and inhibit calcium signaling, in this study, we investigated whether sodium citrate could reduce exhaustion and enhance CAR-T cell function.

Methods

We constructed anti-CD70 CAR-T cells and cultured them in the presence of sodium citrate. The characteristics and functionality of sodium citrate-pretreated CAR-T cells were assessed through in vitro and in vivo experiments. To further validate our observation, we also treated anti-mesothelin (MSLN) CAR-T cells with sodium citrate and detected the phenotypes and anti-tumor function of CAR-T cells.

Results

We found that sodium citrate-pretreated anti-CD70 CAR-T cells exhibited reduced exhaustion, increased memory T cell proportions, and enhanced anti-tumor efficacy both in vitro and in vivo. Notably, sodium citrate treatment improved the in vivo persistence of CAR-T cells and prevented tumor recurrence. These beneficial effects were also observed in anti-MSLN CAR-T cells. Transcriptomic and metabolite analyses revealed that sodium citrate inhibited calcium signaling, mTORC1 activity, and glycolysis pathways, thus modulating T cell exhaustion and differentiation.

Discussion

Our findings suggest that sodium citrate supplementation during CAR-T cell expansion could be a promising strategy to improve CAR-T therapy for solid tumors by preventing exhaustion and promoting memory T cell formation.

Multi-Targeting CAR-T Cell Strategies to Overcome Immune Evasion in Lymphoid and Myeloid Malignancies

BACKGROUND

Chimeric antigen receptor (CAR)-T cell therapy has become a groundbreaking treatment for hematological malignancies, particularly lymphomas and multiple myeloma, with high remission rates in refractory and relapsed patients. However, most CAR-T therapies target a single antigen, such as CD19, which can result in immune evasion through antigen escape. This mechanism describes the downregulation or complete loss of the targeted antigen by the tumor cells, eventually leading to relapse. To address this issue, multi-targeting strategies like logic-gated CARs, adapter CARs, or combination therapies can increase the potency of CAR-T cells. These approaches aim to minimize immune evasion by targeting multiple antigens simultaneously, thereby increasing treatment durability. Additionally, advanced tools such as next-generation sequencing (NGS), direct stochastic optical reconstruction microscopy (dSTORM), or multiparametric flow cytometry are helping to identify novel tumor-specific targets and improve therapy designs.

SUMMARY

This review explores the current landscape of CAR-T cell therapies in lymphoid and myeloid malignancies, highlights ongoing clinical trials, and discusses the future of these innovative multi-targeting approaches to improve patient outcome.

KEY MESSAGES

Antigen escape limits CAR-T cell therapy success, but multi-targeting strategies like logic gates and adapter CARs offer solutions. Optimizing antigen selection and CAR design, along with larger clinical trials, is essential for improving patient outcomes. Personalization using advanced technologies like CRISPR screening and single-cell RNA sequencing can enhance durability and effectiveness of treatments for heavily pretreated patients.

A pooled CRISPR screen identifies the Tα2 enhancer element as a driver of TRA expression in a subset of mature human T lymphocytes

The T cell receptor (TCR) is crucial for immune responses and represents a pivotal therapeutic target for CAR T cell therapies. However, which enhancer elements drive the constitutive expression of the TCRα chain in mature, peripheral T cells has not been well defined. Earlier work has suggested that enhancer alpha is inactive in mature peripheral T cells and that an alternative enhancer element in the 5' J region was driving TRA expression, while more recent findings indicated the opposite. Here, we applied a pooled CRISPR screen to probe a large genomic region proximal to the human TRA gene for the presence of regulatory elements. Interestingly, no sgRNA targeting the 5' J region was identified that influenced TRA expression. In contrast, several sgRNAs targeting enhancer alpha element Tα2, were identified that compromised the expression of the TCRα chain in Jurkat E6.1, as well as in a subset of human primary T cells. Our results provide new insights into the regulation of TRA in human peripheral T cells, advancing our understanding of how constitutive TRA expression is driven and regulated.

Chimeric Antigen Receptor-T Cells in Colorectal Cancer: Pioneering New Avenues in Solid Tumor Immunotherapy

Colorectal cancer (CRC) remains a major global health burden, being one of the most prevalent cancers with high mortality rates. Despite advances in conventional treatment modalities, patients with metastatic CRC often face limited options and poor outcomes. Chimeric antigen receptor-T (CAR-T) cell therapy, initially successful in hematologic malignancies, presents a promising avenue for treating solid tumors, including CRC. This review explores the potential of CAR-T cell therapy in CRC by analyzing clinical trials and highlighting prominent CRC-specific targets. We discuss the challenges such as immunosuppressive microenvironment, tumor heterogeneity, and physical barriers that limit CAR-T efficacy. Emerging strategies, such as logic-gated and dual-targeting CAR-T cells, offer practical solutions to overcome these hurdles. Furthermore, we explore the combination of CAR-T cell therapy with immune checkpoint inhibitors to enhance T-cell persistence and tumor infiltration. As the field continues to evolve, CAR-T cell therapies hold significant potential for revolutionizing the treatment landscape of CRC.

A chimeric antigen receptor tailored to integrate complementary activation signals potentiates the antitumor activity of NK cells

BACKGROUND

Chimeric antigen receptors (CARs) are synthetic receptors that reprogram the target specificity and functions of CAR-expressing effector cells. The design of CAR constructs typically includes an extracellular antigen-binding moiety, hinge (H), transmembrane (TM), and intracellular signaling domains. Conventional CAR constructs are primarily designed for T cells but have been directly adopted for other effector cells, including natural killer (NK) cells, without tailored optimization. Given the benefits of CAR-NK cells over CAR-T cells in terms of safety, off-the-shelf utility, and antigen escape, there is an increasing emphasis on tailoring them to NK cell activation mechanisms.

METHODS

We first have taken a stepwise approach to modifying CAR components such as the combination and order of the H, TM, and signaling domains to achieve such tailoring in NK cells. Functionality of NK-tailored CARs were evaluated in vitro and in vivo in a model of CD19-expressing lymphoma, along with their expression and signaling properties in NK cells.

RESULTS

We found that NK-CAR driven by the synergistic combination of NK receptors NKG2D and 2B4 rather than DNAM-1 and 2B4 induces potent activation in NK cells. Further, more effective CAR-mediated cytotoxicity was observed following the sequential combination of DAP10, but not NKG2D TM, with 2B4 signaling domain despite the capacity of NKG2D TM to recruit endogenous DAP10 for signaling. Accordingly, an NK-CAR incorporating DAP10, 2B4, and CD3ζ signaling domains coupled to CD8α H and CD28 TM domains was identified as the most promising candidate to improve CAR-mediated cytotoxicity. This NK-tailored CAR provided more potent antitumor activity than a conventional T-CAR when delivered to NK cells both in vitro and in vivo.

CONCLUSIONS

Hence, NK receptor-based domains hold great promise for the future of NK-CAR design with potentially significant therapeutic benefits.

Revolutionary Cancer Therapy for Personalization and Improved Efficacy: Strategies to Overcome Resistance to Immune Checkpoint Inhibitor Therapy

Cancer remains a significant public health issue worldwide, standing as a primary contributor to global mortality, accounting for approximately 10 million fatalities in 2020 [...].

Chimeric antigen receptor-modified T-cell therapy: Recent updates and challenges in autoimmune diseases

Chimeric antigen receptor (CAR) T-cell therapy (CAR-T) has revolutionized the treatment of hematologic malignancies, demonstrating significant clinical efficacy and leading to US Food and Drug Administration approval of several CAR T-cell-based products. This success has prompted exploration of CAR-T in other disease areas, including autoimmune diseases (AIDs). CAR-T targeting B cells has been shown to provide clinical and biological improvements in patients with refractory AIDs. The aim of this review is to discuss promising strategies involving CAR-T in AIDs, such as those targeting B cells and T cells, and to explore new approaches targeting fibroblasts or plasmacytoid dendritic cells. Despite these advances, the application of CAR-T in AIDs faces several unique challenges. The quality and functionality of T cells in patients with AIDs may be compromised as a result of previous treatments and the underlying inflammatory state, affecting the generation and efficacy of CAR-T. In addition, achieving adequate tissue biodistribution and persistence of CAR T cells in affected tissues remains a major challenge. Finally, the high costs associated with T-cell production pose economic problems, particularly in the context of chronic diseases, which are far more numerous than the hematologic diseases for which CAR-Ts have been granted marketing authorization to date. If the indications for CAR-T increase significantly, production costs will have to drop drastically in order to obtain reliable economic models.

AND-gated protease-activated nanosensors for programmable detection of anti-tumour immunity

The forward design of biosensors that implement Boolean logic to improve detection precision primarily relies on programming genetic components to control transcriptional responses. However, cell- and gene-free nanomaterials programmed with logical functions may present lower barriers for clinical translation. Here we report the design of activity-based nanosensors that implement AND-gate logic without genetic parts via bi-labile cyclic peptides. These actuate by releasing a reporter if and only if cleaved by a specific pair of proteases. AND-gated nanosensors that detect the concomitant activity of the granzyme B protease secreted by CD8 T cells and matrix metalloproteinases overexpressed by cancer cells identify the unique condition of cytotoxic T cell killing of tumour cells. In preclinical mouse models, AND-gated nanosensors discriminate tumours that are responsive to immune checkpoint blockade therapy from B2m-/- tumours that are resistant to it, minimize signals from tissues without co-localized protease expression including the lungs during acute influenza infection, and release a reporter locally in tissue or distally in the urine for facile detection.

Generation of allogeneic CAR-NKT cells from hematopoietic stem and progenitor cells using a clinically guided culture method

Cancer immunotherapy with autologous chimeric antigen receptor (CAR) T cells faces challenges in manufacturing and patient selection that could be avoided by using 'off-the-shelf' products, such as allogeneic CAR natural killer T (AlloCAR-NKT) cells. Previously, we reported a system for differentiating human hematopoietic stem and progenitor cells into AlloCAR-NKT cells, but the use of three-dimensional culture and xenogeneic feeders precluded its clinical application. Here we describe a clinically guided method to differentiate and expand IL-15-enhanced AlloCAR-NKT cells with high yield and purity. We generated AlloCAR-NKT cells targeting seven cancers and, in a multiple myeloma model, demonstrated their antitumor efficacy, expansion and persistence. The cells also selectively depleted immunosuppressive cells in the tumor microenviroment and antagonized tumor immune evasion via triple targeting of CAR, TCR and NK receptors. They exhibited a stable hypoimmunogenic phenotype associated with epigenetic and signaling regulation and did not induce detectable graft versus host disease or cytokine release syndrome. These properties of AlloCAR-NKT cells support their potential for clinical translation.