Monocyte-derived IL-1 and IL-6 are differentially required for cytokine-release syndrome and neurotoxicity due to CAR T cells

Advancements in the design and function of bispecific CAR-T cells targeting B Cell-Associated tumor antigens

Single-targeted CAR-T has exhibited notable success in treating B-cell tumors, effectively improving patient outcomes. However, the recurrence rate among patients remains above fifty percent, primarily attributed to antigen escape and the diminished immune persistence of CAR-T cells. Over recent years, there has been a surge of interest in bispecific CAR-T cell therapies, marked by an increasing number of research articles and clinical applications annually. This paper undertakes a comprehensive review of influential studies on the design of bispecific CAR-T in recent years, examining their impact on bispecific CAR-T efficacy concerning disease classification, targeted antigens, and CAR design. Notable distinctions in antigen targeting within B-ALL, NHL, and MM are explored, along with an analysis of how CAR scFv, transmembrane region, hinge region, and co-stimulatory region design influence Bi-CAR-T efficacy across different tumors. The summary provided aims to serve as a reference for designing novel and improved CAR-Ts, facilitating more efficient treatment for B-cell malignant tumors.

CAR T cells in solid tumors and metastasis: paving the way forward

CAR T cell therapy, hailed as a breakthrough in cancer treatment due to its remarkable outcomes in hematological malignancies, encounters significant hurdles when applied to solid tumors. While notable responses to CAR T cells remain sporadic in these patients, challenges persist due to issues such as on-target off-tumor toxicity, difficulties in their trafficking and infiltration into the tumor, and the presence of a hostile and immunosuppressive microenvironment. This review aims to explore recent endeavors aimed at overcoming these obstacles in CAR T cell therapy for solid tumors. Specifically, we will delve into promising strategies for enhancing tumor specificity through antigen targeting, addressing tumor heterogeneity, overcoming physical barriers, and counteracting the immune-suppressive microenvironment.

Advances in CAR-T therapy for central nervous system tumors

The application of chimeric antigen receptor T-cell therapy in central nervous system tumors has significantly advanced; however, challenges pertaining to the blood-brain barrier, immunosuppressive microenvironment, and antigenic heterogeneity continue to be encountered, unlike its success in hematological malignancies such as acute lymphoblastic leukemia and diffuse large B-cell lymphomas. This review examined the research progress of chimeric antigen receptor T-cell therapy in gliomas, medulloblastomas, and lymphohematopoietic tumors of the central nervous system, focusing on chimeric antigen receptor T-cells targeting antigens such as EGFRvIII, HER2, B7H3, GD2, and CD19 in preclinical and clinical studies. It synthesized current research findings to offer valuable insights for future chimeric antigen receptor T-cell therapeutic strategies for central nervous system tumors and advance the development and application of this therapeutic modality in this domain.

Optimizing CAR-T cell therapy for solid tumors: current challenges and potential strategies

Chimeric antigen receptor (CAR)-T cell therapy demonstrates substantial efficacy in various hematological malignancies. However, its application in solid tumors is still limited. Clinical studies report suboptimal outcomes such as reduced cytotoxicity of CAR-T cells and tumor evasion, underscoring the need to address the challenges of sliding cytotoxicity in CAR-T cells. Despite improvements from fourth and next-generation CAR-T cells, new challenges include systemic toxicity from continuously secreted proteins, low productivity, and elevated costs. Recent research targets genetic modifications to boost killing potential, metabolic interventions to hinder tumor progression, and diverse combination strategies to enhance CAR-T cell therapy. Efforts to reduce the duration and cost of CAR-T cell therapy include developing allogenic and in-vivo approaches, promising significant future advancements. Concurrently, innovative technologies and platforms enhance the potential of CAR-T cell therapy to overcome limitations in treating solid tumors. This review explores strategies to optimize CAR-T cell therapies for solid tumors, focusing on enhancing cytotoxicity and overcoming application restrictions. We summarize recent advances in T cell subset selection, CAR-T structural modifications, infiltration enhancement, genetic and metabolic interventions, production optimization, and the integration of novel technologies, presenting therapeutic approaches that could improve CAR-T cell therapy's efficacy and applicability in solid tumors.

Comprehensive mapping of immune perturbations associated with secondary hemophagocytic lymphohistiocytosis

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a hyperinflammatory syndrome characterized by immune disorders. It is imperative to elucidate the immunophenotypic panorama and the interactions among these cells in patients. Human peripheral blood mononuclear cells were collected from healthy donors and sHLH patients and tested using multicolor flow cytometry. We used FlowSOM to explore and visualize the immunophenotypic characteristics of sHLH. By demonstrating the phenotypes of immune cells, we discovered that sHLH patients had significantly higher levels of CD56+ monocytes, higher levels of myeloid-derived suppressor cells, low-density neutrophil-to-T cell ratio, and higher heterogeneous T cell activation than healthy donors. However, natural killer cell cytotoxicity and function were impaired. We then assessed the correlations among 30 immune cell types and evaluated metabolic analysis. Our findings demonstrated polymorphonuclear myeloid-derived suppressor cells, CD56+ monocytes, and neutrophil-to-T cell ratio were elevated abnormally in sHLH patients, which may indicate an association with immune overactivation and inflammatory response. We are expected to confirm that they are involved in the occurrence of the disease through further in-depth research.

CAR T Cells and T-Cell Therapies for Cancer: A Translational Science Review

Importance

Chimeric antigen receptor (CAR) T cells are T lymphocytes that are genetically engineered to express a synthetic receptor that recognizes a tumor cell surface antigen and causes the T cell to kill the tumor cell. CAR T treatments improve overall survival for patients with large B-cell lymphoma and progression-free survival for patients with multiple myeloma.

Observations

Six CAR T-cell products are approved by the US Food and Drug Administration (FDA) for 6 hematologic malignancies: B-cell acute lymphoblastic leukemia, large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, chronic lymphocytic leukemia, and multiple myeloma. Compared with standard chemotherapy followed by stem cell transplant, CAR T cells improved 4-year overall survival in patients with large B-cell lymphoma (54.6% vs 46.0%). Patients with pediatric acute lymphoblastic leukemia achieved durable remission after CAR T-cell therapy. At 3-year follow-up, 48% of patients were alive and relapse free. In people with multiple myeloma treated previously with 1 to 4 types of non-CAR T-cell therapy, CAR T-cell therapy prolonged treatment-free remissions compared with standard treatments (in 1 trial, CAR T-cell therapy was associated with progression-free survival of 13.3 months compared with 4.4 months with standard therapy). CAR T-cell therapy is associated with reversible acute toxicities, such as cytokine release syndrome in approximately 40% to 95% of patients, and neurologic disorders in approximately 15% to 65%. New CAR T-cell therapies in development aim to increase efficacy, decrease adverse effects, and treat other types of cancer. No CAR T-cell therapies are FDA approved for solid tumors, but recently, 2 other T lymphocyte-based treatments gained approvals: 1 for melanoma and 1 for synovial cell sarcoma. Additional cellular therapies have attained responses for certain solid tumors, including pediatric neuroblastoma, synovial cell sarcoma, melanoma, and human papillomavirus-associated cancers. A common adverse effect occurring with these T lymphocyte-based therapies is capillary leak syndrome, which is characterized by fluid retention, pulmonary edema, and kidney dysfunction.

Conclusions and Relevance

CAR T-cell therapy is an FDA-approved therapy that has improved progression-free survival for multiple myeloma, improved overall survival for large B-cell lymphoma, and attained high rates of cancer remission for other hematologic malignancies such as acute lymphoblastic leukemia, follicular lymphoma, and mantle cell lymphoma. Recently approved T lymphocyte-based therapies demonstrated the potential for improved outcomes in solid tumor malignancies.

Targeting cytokine networks in neuroinflammatory diseases

In neuroinflammatory diseases, systemic (blood-borne) leukocytes invade the central nervous system (CNS) and lead to tissue damage. A causal relationship between neuroinflammatory diseases and dysregulated cytokine networks is well established across several preclinical models. Cytokine dysregulation is also observed as an inadvertent effect of cancer immunotherapy, where it often leads to neuroinflammation. Neuroinflammatory diseases can be separated into those in which a pathogen is at the centre of the immune response and those of largely unknown aetiology. Here, we discuss the pathophysiology, cytokine networks and therapeutic landscape of 'sterile' neuroinflammatory diseases such as multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), neurosarcoidosis and immune effector cell-associated neurotoxicity syndrome (ICANS) triggered by cancer immunotherapy. Despite successes in targeting cytokine networks in preclinical models of neuroinflammation, the clinical translation of targeting cytokines and their receptors has shown mixed and often paradoxical responses.

Efficacy and risk of donor-derived CAR-T treatment of relapsed B-cell acute lymphoblastic leukemia after hematopoietic stem cell transplantation

The one-year survival rate for patients experiencing a relapse of B-cell acute lymphocytic leukemia (B-ALL) following hematopoietic stem cell transplantation (HSCT) is approximately 30%. Patients experiencing a relapse after allogeneic HSCT frequently encounter difficulties in obtaining autologous CAR-T products. We conducted a study involving 14 patients who received donor-derived CAR-T therapy for relapsed B-ALL following HSCT between August 2019 and May 2023 in our center. The results revealed a CR/CRi rate of 78.6% (11/14), a GVHD rate of 21.4% (3/14), and a 1-year overall survival (OS) rate of 56%. Decreased bone marrow donor cell chimerism in 9 patients recovered after CAR-T therapy. The main causes of death were disease progression and infection. Further analysis showed that GVHD (HR 7.224, 95% CI 1.42-36.82, P = 0.017) and platelet recovery at 30 days (HR 6.807, 95% CI 1.61-28.83, P = 0.009) are significantly associated with OS after CAR-T therapy. Based on the findings, we conclude that donor-derived CAR-T cells are effective in treating relapsed B-ALL patients following HSCT. Additionally, GVHD and poor platelet recovery impact OS, but further verification with a larger sample size is needed.

Glycolytic activity following anti-CD19 CAR-T cell infusion in non-Hodgkin lymphoma

Energy metabolism of chimeric antigen receptor-T cells (CAR-T) activation in humans remains unexplored. As a glycolytic activity surrogate, we investigated the dynamics of peripheral blood (PB) lactate in the first weeks post-CAR-T infusion. In 17 patients treated with CD28 harbording anti-CD19 CAR-T for relapsed/refractory non-Hodgkin lymphomas, PB lactate levels increased following CAR-T infusion. Elevated lactate levels correlated with longer CAR-T persistence and higher CD8+/CD4+ ratio. Peripheral blood lactate kinetics may reflect immune cells activation and be useful for bedside monitoring.

Rational Protein Engineering to Enhance MHC-Independent T-cell Receptors

Chimeric antigen receptor (CAR)-based therapies have pioneered synthetic cellular immunity but remain limited in their long-term efficacy. Emerging data suggest that dysregulated CAR-driven T-cell activation causes T-cell dysfunction and therapeutic failure. To re-engage the precision of the endogenous T-cell response, we designed MHC-independent T-cell receptors (miTCR) by linking antibody variable domains to T-cell receptor constant chains. Using predictive modeling, we observed that this standard "cut and paste" approach to synthetic protein design resulted in myriad biochemical conflicts at the hybrid variable-constant domain interface. Through iterative modeling and sequence modifications, we developed structure-enhanced miTCRs which significantly improved receptor-driven T-cell function across multiple tumor models. We found that 41BB costimulation specifically prolonged miTCR T-cell persistence and enabled improved leukemic control in vivo compared with classic CAR T cells. Collectively, we have identified core features of hybrid receptor structure responsible for regulating function. Significance: Improving the durability of engineered T-cell immunotherapies is critical to enhancing efficacy. We used a structure-informed design to evolve improved miTCR function across several models. This work underscores the central role of synthetic receptor structure in T-cell function and provides a framework for improved receptor engineering.

Tocilizumab Prophylaxis Following Axicabtagene Ciloleucel in Relapsed or Refractory Large B-Cell Lymphoma

Axicabtagene ciloleucel (axi-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved in patients with relapsed/refractory (R/R) large B-cell lymphoma (LBCL). Most patients treated with axi-cel experience cytokine release syndrome (CRS) and/or adverse neurologic events (NEs). To explore potential approaches for reducing CAR T-cell-related toxicities with axi-cel, several safety expansion cohorts were added to the pivotal ZUMA-1 trial. ZUMA-1 Cohort 3 was an exploratory safety cohort that investigated the use of the IL-6 receptor-blocking antibody tocilizumab and anticonvulsant levetiracetam as prophylaxis against CRS and NEs in patients treated with axi-cel. Patients with R/R LBCL were enrolled in Cohort 3 and received conditioning chemotherapy on d -5 through -3 followed by a single infusion of axi-cel (2 × 106 cells/kg) on d 0. Prophylactic tocilizumab (8 mg/kg) was administered 48 h after axi-cel infusion. Primary endpoints were incidence and severity of CRS and NEs. Key secondary endpoints included the incidence of adverse events, objective response rate (ORR), duration of response, progression-free survival, overall survival (OS), and biomarker analyses (eg, circulating CAR T cells, cytokines, chemokines). Forty-two patients were enrolled in Cohort 3, 38 of whom received axi-cel. In the 24-month analysis, any-grade CRS and NEs occurred in 92% and 87% of patients, and Grade ≥3 CRS and NEs occurred in 3% and 42% of patients, respectively. One Grade 5 NE (cerebral edema) occurred. With 24-mo minimum follow-up, the ORR was 63%, and 39.5% of patients had ongoing response. With 48-month follow-up, median OS was 34.8 mo (95% CI, 5.4-not estimable). CAR T-cell expansion in ZUMA-1 Cohort 3 was comparable with pivotal Cohorts 1 and 2. Consistent with tocilizumab-mediated inhibition of IL-6R, serum IL-6 levels were increased relative to Cohorts 1 and 2. Grade ≥3 NEs were associated with elevated IL-6 levels, proinflammatory cytokines, and myeloid cells in the cerebrospinal fluid. Based on these findings, prophylactic tocilizumab is not recommended to prevent CAR T-cell-related adverse events, and beneficial effects of prophylactic levetiracetam remain uncertain in patients with R/R LBCL.

Dual targeting chimeric antigen receptor cells enhance antitumour activity by overcoming T cell exhaustion in pancreatic cancer

BACKGROUND AND PURPOSE

Although our previous data indicated that claudin 18 isoform 2 (CLDN18.2)-targeted chimeric antigen receptor (CAR) T cells displayed remarkable clinical efficacy in CLDN18.2-positive gastric cancer, their efficacy is limited in pancreatic ductal adenocarcinoma (PDAC). The tumour microenvironment (TME) is one of the main obstacles to the efficacy of CAR-T and remodelling the TME may be a possible way to overcome this obstacle. The TME of PDAC is characterized by abundant cancer-related fibroblasts (CAFs), which hinder the infiltration and function of CLDN18.2-targeted CAR-T cells. The expression of fibroblast activation protein alpha (FAP) is an important feature of active CAFs, providing potential targets for eliminating CAFs.

EXPERIMENTAL APPROACH

In this study, we generated 10 FAP/CLDN 18.2 dual-targeted CAR-T cells and evaluated their anti-tumour ability in vitro and in vivo.

KEY RESULTS

Compared with conventional CAR-T cells, some dual-targeted CAR-T cells showed improved therapeutic effects in mouse pancreatic cancers. Further, dual-targeted CAR-T cells with better anti-tumour effect could suppress the recruitment of myeloid-derived suppressor cells (MDSCs) to improve the immunosuppressive TME, which contributes to the survival of CD8+ T cells. Moreover, dual-targeted CAR-T cells reduced the exhaustion of T cells in transforming TGF-β dependent manner.

CONCLUSION AND IMPLICATIONS

The dual-targeted CAR-T cells obtained enhancement of T effector function, inhibition of T cell exhaustion, and improvement of tumour microenvironment. Our findings provide a theoretical rationale for dual-targeted FAP/CLDN 18.2 CAR-T cells therapy in PDAC.

CAR T-cell-associated neurotoxicity: A comprehensive review

Chimeric antigen receptor T-cell (CAR T-cell) therapies have emerged as a promising treatment modality for several malignancies, particularly haematological malignancies, by inducing robust antitumour responses. However, CAR T-cell therapies are associated with a spectrum of adverse events, including neurological complications. We here provide a review of neurological adverse events observed in patients undergoing CAR T-cell therapy, focusing on their incidence, clinical manifestations, underlying mechanisms and potential management strategies.

Protocol to measure human IL-6 secretion from CAR T cell-primed macrophage and monocyte lineage cells in vitro and in vivo using humanized mice

Chimeric antigen receptor (CAR) T cell therapy often causes serious toxicities, such as cytokine release syndrome (CRS), mainly due to interleukin-6 (IL-6) secreted by monocyte lineage cells. Here, we describe a protocol to generate anti-CD19 CAR T cells and quantify human monocyte-derived IL-6 cocultured with CAR T cells and target tumor cells in vitro. We further describe a protocol to generate a humanized mouse model and evaluate CAR T cell-associated plasma IL-6 levels in vivo. For complete details on the use and execution of this protocol, please refer to Yoshikawa et al.1.

Clonal hematopoiesis of indeterminate potential: the root cause of, and fertile ground for, hematological malignancies

Clonal hematopoiesis (CH) of indeterminate potential (CHIP), characterized by propagation of blood cell clones carrying somatic mutations in specific driver genes, is increasingly recognized as a critical factor in the development of hematological malignancies. This phenomenon, which often emerges with age, underscores the complex interplay between genetic predisposition and environmental influences in cancer initiation and progression. Recent years have witnessed significant advances in our understanding of the link between CHIP and hematological diseases. In this review, we provide a comprehensive overview of the features of CHIP and explore its role in promoting tumorigenesis and influencing treatment outcomes for blood cancers. Finally, we summarize current available tools for risk stratification and discuss management strategies for patients with CHIP.

Revolutionizing cancer treatment: an in-depth exploration of CAR-T cell therapies

Cancer is a leading cause of fatality worldwide. Due to the heterogeneity of cancer cells the effectiveness of various conventional cancer treatment techniques is constrained. Thus, researchers are diligently investigating therapeutic approaches like immunotherapy for effective tumor managements. Immunotherapy harnesses the inherent potential of patient's immune system to achieve desired outcomes. Within the realm of immunotherapy, CAR-T (Chimeric Antigen Receptor T) cells, emerges as a revolutionary innovation for cancer therapy. The process of CAR-T cell therapy entails extracting the patient's T cells, altering them with customized receptors designed to specifically recognize and eradicate the tumor cells, and then reinfusing the altered cells into the patient's body. Although there has been significant progress with CAR-T cell therapy in certain cases of specific B-cell leukemia and lymphoma, its effectiveness is hindered in hematological and solid tumors due to the challenges such as severe toxicities, restricted tumor infiltration, cytokine release syndrome and antigen escape. Overcoming these obstacles requires innovative approaches to design more effective CAR-T cells, which require a competent and diverse team to develop and implement. This comprehensive review addresses numerous therapeutic issues and provides a strategic solution while providing a deep understanding of the structural intricacies and production processes of CAR-T cells. In addition, this review explores the practical aspects of CAR-T cell therapy in clinical settings.

NSGS mice humanized with cord blood mononuclear cells show sustained and functional myeloid-lymphoid representation with limited graft-versus-host disease

Humanized immunodeficient mice serve as critical models for investigating the functional interplay between transplanted human cells and a pre-reconstituted human immune system. These models facilitate the study of molecular and cellular pathogenic mechanisms and enable the evaluation of the efficacy and toxicity of immunotherapies, thereby accelerating their preclinical and clinical development. Current strategies rely on inefficient, long-term/delayed hematopoietic reconstitution by CD34+ hematopoietic progenitors or short-term reconstitution with peripheral blood mononuclear cells (PB-MNCs) associated with high rates of graft-versus-host disease (GvHD) and an inefficient representation of immune cell populations. Here, we hypothesized that immunologically naïve cord blood mononuclear cells (CB-MNCs) could serve as a superior alternative, providing long-lasting and functionally effective immune reconstitution. We conducted a comprehensive comparison between the non-obese diabetic (NOD).Cg-Prkdc∧ˆscid-IL2rg∧ˆtm1Wjl/SzJ (NSG) and NSG-Tg(CMV-IL3,CSF2,KITLG)∧ˆ1Eav/MloySzJ (NSGS) immunodeficient mouse models following humanization with either PB-MNCs or CB-MNCs. We assessed the engraftment dynamics of various human immune cells over time and monitored the development of GvHD in both models. For the most promising model, we extensively evaluated immune cell functionality in vitro and in vivo using sarcoma and leukemia xenografts. Humanizing NSGS mice with CB-MNCs results in a rapid, robust, and sustained representation of a diverse range of functional human lymphoid and myeloid cell populations while minimizing GvHD incidence. In this model, human immune cell populations significantly impair the growth and engraftment of sarcoma and B-cell acute lymphoblastic leukemia cells, with a significant inverse correlation between immune cell levels and tumor growth. This study establishes a fast, efficient, and reliable in vivo platform for various applications in cancer immunotherapy, particularly for exploring the complex interactions between cancer cells, immune cells, and the tumor microenvironment in vivo, prior to clinical development.

Novel OX40 and 4-1BB derived spacers enhance CD30 CAR activity and safety in CD30 positive lymphoma models

The chimeric antigen receptor (CAR) derived from the CD30 specific murine antibody, HRS-3, has produced promising clinical efficacy with a favorable safety profile in the treatment of relapsed or refractory CD30-positive lymphomas. However, persistence of the autologous CAR-T cells was brief, and many patients relapsed a year after treatment. The lack of persistence may be attributed to the use of a wild-type immunoglobulin (Ig)G1 spacer that can associate with Fc receptors. We first identified the cysteine-rich domain (CRD) 5 of CD30 as the primary binding epitope of HRS-3 and armed with this insight, attempted to improve the HRS-3 CAR functionality with a panel of novel spacer designs. We demonstrate that HRS-3 CARs with OX40 and 4-1BB derived spacers exhibited similar anti-tumor efficacy, circumvented interactions with Fc receptors, and secreted lower levels of cytokines in vitro than a CAR employing the IgG1 spacer. Humanization of the HRS-3 scFv coupled with the 4-1BB spacer preserved potent on-target, on-tumor efficacy, and on-target, off-tumor safety. In a lymphoma mouse model of high tumor burden, T cells expressing humanized HRS-3 CD30.CARs with the 4-1BB spacer potently killed tumors with low levels of circulating inflammatory cytokines, providing a promising candidate for future clinical development in the treatment of CD30-positive malignancies.

Targeted counteracting of overactive macrophages by melittin stable-loaded solid lipid nanoparticles alleviates cytokine storm and acute inflammatory injury

The continuous activation of macrophages play a critical role in the pathogenesis of cytokine storm (CS). Considering that CS results from the participation of multiple cytokines, the therapeutic effect of a single cytokine or its receptor-targeted blockade therapy remains uncertain. Melittin, which can systematically suppress the overexpression of proinflammatory mediators via inhibiting the mitogen-activated protein kinase and nuclear factor kappa-B pathways in activated macrophages, shows great potential in alleviating CS and acute inflammatory injury (AII). However, its clinical application is limited by its hemolytic activity, non-specific cytotoxicity and lack of targeting. In this study, a folic acid-modified and melittin stable-loaded solid lipid nanoparticle (Fa-MpG@LNP) with a core-shell structure was developed for CS control via targeted inhibition of the overproduction of proinflammatory mediators in activated macrophages with specific expression of folate receptor-β. The resultant Fa-MpG@LNP showed ideal physicochemical properties and stability, low hemolytic activity and non-specific cytotoxicity, and it can specifically bind to lipopolysaccharide (LPS)-stimulated macrophages and effectively reduce the elevated levels of proinflammatory mediators. After intravenous administration, the Fa-MpG@LNP accumulated at inflamed tissue and significantly downregulate the overproduction of proinflammatory cytokines in tissue-infiltrated macrophages, resulting in a significant decrease of cytokine concentration in inflamed tissue and serum in LPS-induced acute pneumonia mice, and finally alleviate AII with undetectable toxic side effects. These results indicate the clinical application potential of Fa-MpG@LNP in alleviating CS and its related symptoms.

An integrated perspective on measuring cytokines to inform CAR-T bioprocessing

Chimeric antigen receptor (CAR)-T cells are emerging as a generation-defining therapeutic however their manufacture remains a major barrier to meeting increased market demand. Monitoring critical quality attributes (CQAs) and critical process parameters (CPPs) during manufacture would vastly enrich acquired information related to the process and product, providing feedback to enable real-time decision making. Here we identify specific CAR-T cytokines as value-adding analytes and discuss their roles as plausible CPPs and CQAs. High sensitivity sensing technologies which can be easily integrated into manufacture workflows are essential to implement real-time monitoring of these cytokines. We therefore present biosensors as enabling technologies and evaluate recent advancements in cytokine detection in cell cultures, offering promising translatability to CAR-T biomanufacture. Finally, we outline emerging sensing technologies with future promise, and provide an overall outlook on existing gaps to implementation and the optimal sensing platform to enable cytokine monitoring in CAR-T biomanufacture.

Hypophosphatemia Correction Reduces ICANS Incidence and Duration in CAR T-cell Therapy: A Pooled Clinical Trial Analysis

A common complication of chimeric antigen receptor (CAR) T-cell therapy is immune effector cell-associated neurotoxicity syndrome (ICANS), which presents with encephalopathy, aphasia, inattention, somnolence, seizures, weakness, or cerebral edema. Despite its significant morbidity, there are currently no effective targeted treatments. Given the clinical similarities between ICANS and the neurological manifestations of acute hypophosphatemia, we retrospectively reviewed 499 patients treated with CD19-targeted CAR T-cell therapy across multiple clinical trials between 2015 and 2020. In addition to clinical toxicities experienced by the patients, we also interrogated the impact of serum electrolyte data and repletion of corresponding electrolyte deficiencies with ICANS incidence, severity, and duration. Hypophosphatemia was a common occurrence in CAR T-cell recipients and the only electrolyte derangement associated with a significantly higher cumulative incidence of ICANS. Moreover, phosphorus repletion in patients with hypophosphatemia was associated with significantly decreased ICANS incidence and duration. Hypophosphatemia was uniquely associated with encephalopathy neurological adverse events, which also showed the strongest positive correlation with both ICANS and cytokine release syndrome severity. These findings suggest that serum phosphorus could be a reliable biomarker for ICANS, and expeditious, goal-directed phosphorus repletion in response to serum hypophosphatemia could be a safe, inexpensive, and widely available intervention for such patients.

SIGNIFICANCE

Herein we show that phosphorus repletion in patients with hypophosphatemia receiving anti-CD19 chimeric antigen receptor T-cell therapeutics was associated with significantly decreased immune effector cell-associated neurotoxicity syndrome (ICANS) incidence and symptom duration. Given the significant morbidity associated with ICANS and lack of targeted interventions, hypophosphatemia may serve as both a useful biomarker and an inexpensive intervention for ICANS.

Systemic Multifunctional Nanovaccines for Potent Personalized Immunotherapy of Acute Myeloid Leukemia

Hematological malignancies (HM) like acute myeloid leukemia (AML) are often intractable. Cancer vaccines possibly inducing robust and broad anti-tumor immune responses may be a promising treatment option for HM. Few effective vaccines against blood cancers are, however, developed to date partly owing to insufficient stimulation of dendritic cells (DCs) in the body and lacking appropriate tumor antigens (Ags). Here it is found that systemic multifunctional nanovaccines consisting of nucleotide-binding oligomerization domain-containing protein 2 (NOD2) and Toll-like receptor 9 (TLR9) agonists - muramyl dipeptide (MDP) and CpG, and tumor cell lysate (TCL) as Ags (MCA-NV) induce potent and broad immunity against AML. MCA-NV show complementary stimulation of DCs and prime homing to lymphoid organs following systemic administration. Of note, in orthotopic AML mouse models, intravenous infusion of different vaccine formulations elicits substantially higher anti-AML efficacies than subcutaneous administration. Systemic MCA-NV cure 78% of AML mice and elicit long-term immune memory with 100% protection from rechallenging AML cells. Systemic MCA-NV can also serve as prophylactic vaccines against the same AML. These systemic nanovaccines utilizing patient TCL as Ags and dual adjuvants to elicit strong, durable, and broad immune responses can provide a personalized immunotherapeutic strategy against AML and other HM.

Mobilizing CARs: Benefits, drawbacks, and directions for outpatient CAR T-cell therapy

Chimeric antigen receptor T-cell (CAR-T) therapy has heralded a new era in the treatment of various hematological malignancies, increasingly being utilized in earlier lines of therapy. Moreover, cellular therapies are currently under investigation for their potential in treating solid malignancies and autoimmune disorders. As the scope of indications for CAR-T therapy continues to expand, along with the associated reductions in costs and hospital admissions, many medical centers are transitioning towards outpatient CAR-T models. Moreover, ongoing efforts to mitigate complications such as cytokine release syndrome (CRS) or neurotoxicity include the development of premedication strategies, prompt management of adverse events, and the advancement of newer, safer CAR-T cell therapies. However, despite these advancements, the inherent risk of these life-threatening complications remains a critical concern in CAR-T therapy. Institutions must diligently anticipate and effectively manage these complications to ensure the safety and well-being of patients undergoing CAR-T therapy. This includes establishing robust protocols for timely identification and intervention of adverse events, and seamless pathways for transitioning patients to a higher level of care if necessary. This review provides an overview of the current landscape of outpatient CAR-T therapy and offers essential insights into the key clinical and operational considerations needed to implement a successful outpatient CAR-T program.

Safe and potent anti-CD19 CAR T-cells with shRNA-IL-6 gene silencing element in patients with refractory or relapsed B-cell acute lymphoblastic leukemia

Severe cytokine release syndrome (sCRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) have limited the widespread use of chimeric antigen receptor T (CAR T)-cell therapy. We designed a novel anti-CD19 CAR (ssCART-19) with a small hairpin RNA (shRNA) element to silence the interleukin-6 (IL-6) gene, hypothesizing it could reduce sCRS and ICANS by alleviating monocyte activation and proinflammatory cytokine release. In a post hoc analysis of two clinical trials, we compared ssCART-19 with common CAR T-cells (cCART-19) in relapsed/refractory B-cell acute lymphoblastic leukemia (r/r B-ALL). Among 87 patients, 47 received ssCART-19 and 40 received cCART-19. Grade ≥3 CRS occurred in 14.89% (7/47) of the ssCART-19 group versus 37.5% (15/40) in the cCART-19 group (p = 0.036). ICANS occurred in 4.26% (2/47) of the ssCART-19 group (all grade 1) compared to 15% (2/40) of the cCART-19 group. Patients in the ssCART-19 group showed comparable rates of treatment response (calculated with rates of complete remission and incomplete hematological recovery) were 91.49% (43/47) for ssCART-19 and 85% (34/40) for cCART-19 (p = 0.999). With a median follow-up of 21.9 months, cumulative nonrelapse mortality was 10.4% for ssCART-19 and 13.6% for cCART-19 (p = 0.33). Median overall survival was 37.17 months for ssCART-19 and 32.93 months for cCART-19 (p = 0.40). Median progression-free survival was 24.17 months for ssCART-19 and 9.33 months for cCART-19 (p = 0.23). These data support the safety and efficacy of ssCART-19 for r/r B-ALL, suggesting its potential as a promising therapy.

CAR-T and CAR-NK as cellular cancer immunotherapy for solid tumors

In the past decade, chimeric antigen receptor (CAR)-T cell therapy has emerged as a promising immunotherapeutic approach for combating cancers, demonstrating remarkable efficacy in relapsed/refractory hematological malignancies in both pediatric and adult patients. CAR-natural killer (CAR-NK) cell complements CAR-T cell therapy by offering several distinct advantages. CAR-NK cells do not require HLA compatibility and exhibit low safety concerns. Moreover, CAR-NK cells are conducive to "off-the-shelf" therapeutics, providing significant logistic advantages over CAR-T cells. Both CAR-T and CAR-NK cells have shown consistent and promising results in hematological malignancies. However, their efficacy against solid tumors remains limited due to various obstacles including limited tumor trafficking and infiltration, as well as an immuno-suppressive tumor microenvironment. In this review, we discuss the recent advances and current challenges of CAR-T and CAR-NK cell immunotherapies, with a specific focus on the obstacles to their application in solid tumors. We also analyze in depth the advantages and drawbacks of CAR-NK cells compared to CAR-T cells and highlight CAR-NK CAR optimization. Finally, we explore future perspectives of these adoptive immunotherapies, highlighting the increasing contribution of cutting-edge biotechnological tools in shaping the next generation of cellular immunotherapy.

A Primer on Chimeric Antigen Receptor T-cell Therapy-related Toxicities for the Intensivist

Chimeric antigen receptor (CAR) T-cell therapy is an innovative treatment approach that has shown remarkable efficacy against several hematologic malignancies. However, its use can be associated with unique and sometimes severe toxicities that require admission to intensive care unit in 30% of patients, and intensivists should be aware of immune-mediated toxicities of CAR T-cell therapy and management of adverse events. We will review available literature on current diagnostic criteria and therapeutic strategies for mitigating these most common toxicities associated with CAR T-cell therapy including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) in the post-infusion period. The authors will also review other toxicities associated with CAR T-cell therapy including cytopenias, acquired immunocompromised states, and infections, and discuss the available literature on best supportive care and prophylaxis recommendations. Critical care medicine specialists play a crucial role in the management of patients undergoing CAR T-cell therapies. With the expanding use of these products in increasing numbers of treating centers, intensivists' roles as part of the multidisciplinary team caring for these patients will have an outsized impact on the continued success of these promising therapies.

Development of human innate immune responses in a humanized mouse model expressing four human myelopoiesis transgenes

Background

Dysregulated innate immune responses underlie multiple inflammatory diseases, but clinical translation of preclinical innate immunity research in mice is hampered by the difficulty of studying human inflammatory reactions in an in vivo context. We therefore sought to establish in vivo human inflammatory responses in NSG-QUAD mice that express four human myelopoiesis transgenes to improve engraftment of a human innate immune system.

Methods

We reconstituted NSG-QUAD mice with human hematopoietic stem and progenitor cells (HSPCs), after which we evaluated human myeloid cell development and subsequent human responses to systemic and local lipopolysaccharide (LPS) challenges.

Results

NSG-QUAD mice already displayed engraftment of human monocytes, dendritic cells and granulocytes in peripheral blood, spleen and liver at 6 weeks after HSPC reconstitution, in which both classical, intermediate and non-classical monocytes were present. These huNSG-QUAD mice responded to intraperitoneal and intranasal LPS challenges with production of NF-κB-dependent human cytokines, a human type I interferon response, as well as inflammasome-mediated production of human IL-1β and IL-18. The latter were specifically abrogated by the NLRP3 inhibitor MCC950, while LPS-induced human monocyte death was not altered. Besides providing proof-of-principle for small molecule testing of human inflammatory reactions in huNSG-QUAD mice, this observation suggests that LPS-induced in vivo release of human NLRP3 inflammasome-generated cytokines occurs in a cell death-independent manner.

Conclusion

HuNSG-QUAD mice are competent for the NF-κB, interferon and inflammasome effectors of human innate immunity, and can thus be utilized to investigate signaling mechanisms and pharmacological targeting of human inflammatory responses in an in vivo setting.

Cytokine-mediated CAR T therapy resistance in AML

Acute myeloid leukemia (AML) is a rapidly progressive malignancy without effective therapies for refractory disease. So far, chimeric antigen receptor (CAR) T cell therapy in AML has not recapitulated the efficacy seen in B cell malignancies. Here we report a pilot study of autologous anti-CD123 CAR T cells in 12 adults with relapsed or refractory AML. CAR T cells targeting CD123+ cells were successfully manufactured in 90.4% of runs. Cytokine release syndrome was observed in 10 of 12 infused individuals (83.3%, 90% confidence interval 0.5-0.97). Three individuals achieved clinical response (25%, 90% confidence interval 0.07-0.53). We found that myeloid-supporting cytokines are secreted during cell therapy and support AML blast survival via kinase signaling, leading to CAR T cell exhaustion. The prosurvival effect of therapy-induced cytokines presents a unique resistance mechanism in AML that is distinct from any observed in B cell malignancies. Our findings suggest that autologous CART manufacturing is feasible in AML, but treatment is associated with high rates of cytokine release syndrome and relatively poor clinical efficacy. Combining CAR T cell therapies with cytokine signaling inhibitors could enhance immunotherapy efficacy in AML and achieve improved outcomes (ClinicalTrials.gov identifier: NCT03766126 ).

Quadriparesis and paraparesis following chimeric antigen receptor T-cell therapy in children and adolescents

ABSTRACT

Immune effector cell-associated neurotoxicity syndrome (ICANS) is a common but potentially severe adverse event associated with chimeric antigen receptor T-cell (CART) therapy, characterized by the development of acute neurologic symptoms following CART infusion. ICANS encompasses a wide clinical spectrum typified by mild to severe encephalopathy, seizures, and/or cerebral edema. As more patients have been treated with CART, new ICANS phenomenology has emerged. We present the clinical course of 5 children who developed acute onset of quadriparesis or paraparesis associated with abnormal brain and/or spine neuroimaging after infusion of CD19- or CD22-directed CART, adverse events not previously reported in children. Orthogonal data from autopsy studies, cerebrospinal fluid (CSF) flow cytometry, and CSF proteomics/cytokine profiling demonstrated chronic white matter destruction, but a notable lack of inflammatory pathologic changes and cell populations. Instead, children with quadriparesis or paraparesis post-CART therapy had lower levels of proinflammatory cytokines, such as interferon gamma, CCL17, CCL23, and CXCL10, than those who did not develop quadriparesis or paraparesis. Taken together, these findings imply a noninflammatory source of this newly described ICANS phenomenon in children. The pathophysiology of some neurologic symptoms following CART may therefore have a more complex etiology than exclusive T-cell activation and excessive cytokine production.

Neurofilament light chain levels as an early predictive biomarker of neurotoxicity after CAR T-cell therapy

Immune effector cell-associated neurotoxicity syndrome (ICANS) remains a significant cause of morbidity associated with CD19-targeted chimeric antigen receptor (CAR) T-cell therapy. Early prediction of patients who will develop ICANS would be crucial to better guide individualized management of high-risk patients, but specific predictive markers are still missing. Serum neurofilament light chain (NfL) levels are a sensitive indicator of neuroaxonal injury in neurological diseases. Elevated NfL levels at the time of CAR T-cell infusion have been associated with the severity of ICANS, but their utility for earlier identification of patients with subclinical neurological damage has not been evaluated.We studied all consecutive adult patients who received commercial CAR T cells for relapsed/refractory B-cell lymphomas at Saint-Louis Hospital between January 2019 and February 2023. Patients with pre-existing or current neurological disease were excluded. NfL levels were quantified in frozen serum collected at the time of the decision to treat (ie, the day of leukapheresis) and at the time of treatment (ie, the day of infusion).Of the 150 study patients, 28% developed ICANS of any grade, including 15.3% of grade 2-4. Receiving a CAR construct with a CD28 domain (58% of patients) was the strongest predictor of grade 2-4 ICANS. Serum NfL levels were significantly higher in patients with grade 2-4 ICANS than in those with grade 0-1 ICANS, both at the time of leukapheresis and infusion. In multivariate models, NfL above the cut-off value was independently associated with grade 2-4 ICANS at leukapheresis (NfL>75 pg/mL, OR 4.2, 95% CI 1.2 to 14.2, p=0.022) and infusion (NfL>58 pg/mL, OR 4.3, 95% CI 1.3 to 13.7, p=0.015).In conclusion, high NfL levels at the time of the decision to proceed with CAR T-cell manufacturing may represent an early surrogate of underlying loss of neuroaxonal integrity that increases the risk of subsequent neurotoxicity. Incorporating NfL levels into the decision-making process based on each patient's risk profile could help determine the appropriate CAR product when possible, and guide the prophylactic or therapeutic management of ICANS.

Advancing CAR T-cell therapies: Preclinical insights and clinical translation for hematological malignancies

Chimeric antigen receptor (CAR) T-cell therapy has achieved significant success in achieving durable and potentially curative responses in patients with hematological malignancies. CARs are tailored fusion proteins that direct T cells to a specific antigen on tumor cells thereby eliciting a targeted immune response. The approval of several CD19-targeted CAR T-cell therapies has resulted in a notable surge in clinical trials involving CAR T cell therapies for hematological malignancies. Despite advancements in understanding response mechanisms, resistance patterns, and adverse events associated with CAR T-cell therapy, the translation of these insights into robust clinical efficacy has shown modest outcomes in both clinical trials and real-world scenarios. Therefore, the assessment of CAR T-cell functionality through rigorous preclinical studies plays a pivotal role in refining therapeutic strategies for clinical applications. This review provides an overview of the various in vitro and animal models used to assess the functionality of CAR T-cells. We discuss the findings from preclinical research involving approved CAR T-cell products, along with the implications derived from recent preclinical studies aiming to optimize the functionality of CAR T-cells. The review underscores the importance of robust preclinical evaluations and the need for models that accurately replicate human disease to bridge the gap between preclinical success and clinical efficacy.

Updates on CAR T cell therapy in multiple myeloma

Multiple myeloma (MM) is a hematological cancer characterized by the abnormal proliferation of plasma cells. Initial treatments often include immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs), and monoclonal antibodies (mAbs). Despite salient progress in diagnosis and treatment, most MM patients typically have a median life expectancy of only four to five years after starting treatment. In recent developments, the success of chimeric antigen receptor (CAR) T-cells in treating B-cell malignancies exemplifies a new paradigm shift in advanced immunotherapy techniques with promising therapeutic outcomes. Ide-cel and cilta-cel stand as the only two FDA-approved BCMA-targeted CAR T-cells for MM patients, a recognition achieved despite extensive preclinical and clinical research efforts in this domain. Challenges remain regarding certain aspects of CAR T-cell manufacturing and administration processes, including the lack of accessibility and durability due to T-cell characteristics, along with expensive and time-consuming processes limiting health plan coverage. Moreover, MM features, such as tumor antigen heterogeneity, antigen presentation alterations, complex tumor microenvironments, and challenges in CAR-T trafficking, contribute to CAR T-cell exhaustion and subsequent therapy relapse or refractory status. Additionally, the occurrence of adverse events such as cytokine release syndrome, neurotoxicity, and on-target, off-tumor toxicities present obstacles to CAR T-cell therapies. Consequently, ongoing CAR T-cell trials are diligently addressing these challenges and barriers. In this review, we provide an overview of the effectiveness of currently available CAR T-cell treatments for MM, explore the primary resistance mechanisms to these treatments, suggest strategies for improving long-lasting remissions, and investigate the potential for combination therapies involving CAR T-cells.

ReCARving the future: bridging CAR T-cell therapy gaps with synthetic biology, engineering, and economic insights

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of hematologic malignancies, offering remarkable remission rates in otherwise refractory conditions. However, its expansion into broader oncological applications faces significant hurdles, including limited efficacy in solid tumors, safety concerns related to toxicity, and logistical challenges in manufacturing and scalability. This review critically examines the latest advancements aimed at overcoming these obstacles, highlighting innovations in CAR T-cell engineering, novel antigen targeting strategies, and improvements in delivery and persistence within the tumor microenvironment. We also discuss the development of allogeneic CAR T cells as off-the-shelf therapies, strategies to mitigate adverse effects, and the integration of CAR T cells with other therapeutic modalities. This comprehensive analysis underscores the synergistic potential of these strategies to enhance the safety, efficacy, and accessibility of CAR T-cell therapies, providing a forward-looking perspective on their evolutionary trajectory in cancer treatment.

Neuroprotection of the P2X7 receptor antagonist A740003 on retinal ganglion cells in experimental glaucoma

The aim of this study was to explore the neuroprotective effects of the P2X7 receptor antagonist A740003 on retinal ganglion cells (RGCs) in chronic intraocular hypertension (COH) experimental glaucoma mouse model. Bioinformatics was used to analyze the glaucoma-related genes. Western blot, real-time fluorescence quantitative PCR, and immunofluorescence staining techniques were employed to explore the mechanisms underlying the neuroprotective effects of A740003 on RGCs in COH retinas. Bioinformatic analysis revealed that oxidative stress, neuroinflammation, and cell apoptosis were highly related to the pathogenesis of glaucoma. In COH retinas, intraocular pressure elevation significantly increased the levels of translocator protein, a marker of microglial activation, which could be reversed by intravitreal preinjection of A740003. A740003 also suppressed the increased mRNA levels of proinflammatory cytokines interleukin (IL) 1β and tumor necrosis factor α in COH retinas. In addition, although the mRNA levels of anti-inflammatory cytokine IL-4 and IL-10 were kept unchanged in COH retinas, administration of A740003 could increase their levels. The mRNA and protein levels of Bax and cleaved caspase-3 were increased in COH retinas, which could be partially reversed by A740003, while the levels of Bcl-2 kept unchanged in COH retinas with or without the injections of A740003. Furthermore, A740003 partially attenuated the reduction in the numbers of Brn-3a-positive RGCs in COH mice. A740003 could provide neuroprotective roles on RGCs by inhibiting the microglia activation, attenuating the retinal inflammatory response, reducing the apoptosis of RGCs, and enhancing the survival of RGCs in COH experimental glaucoma.

Harnessing cytokines to optimize chimeric antigen receptor-T cell therapy for gastric cancer: Current advances and innovative strategies

Enormous patients with gastric cancer (GC) are insensitive to chemotherapy and targeted therapy without the chance of radical surgery, so immunotherapy may supply a novel choice for them. Chimeric antigen receptor (CAR)-T cell therapy has the advantages of higher specificity, stronger lethality, and longer-lasting efficacy, and it has the potential for GC in the future. However, its application still faces numerous obstacles in terms of accuracy, efficacy, and safety. Cytokines can mediate the migration, proliferation, and survival of immune cells, regulate the duration and strength of immune responses, and are involved in the occurrence of severe side effects in CAR-T cell therapy. The expression levels of specific cytokines are associated with the genesis, invasion, metastasis, and prognosis of GC. Applications of cytokines and their receptors in CAR-T cell therapy have emerged, and various cytokines and their receptors have contributed to improving CAR-T cell anti-tumor capabilities. Large amounts of central cytokines in this therapy include chemokines, interleukins (ILs), transforming growth factor-β (TGF-β), and colony-stimulating factors (CSFs). Meanwhile, researchers have explored the combination therapy in treating GC, and several approaches applied to other malignancies can also be considered as references. Therefore, our review comprehensively outlines the biological functions and clinical significance of cytokines and summarizes current advances and innovative strategies for harnessing cytokines to optimize CAR-T cell therapy for GC.

Systemic toxicity of CAR-T therapy and potential monitoring indicators for toxicity prevention

Malignant tumors of the hematologic system have a high degree of malignancy and high mortality rates. Chimeric antigen receptor T cell (CAR-T) therapy has become an important option for patients with relapsed/refractory tumors, showing astonishing therapeutic effects and thus, it has brought new hope to the treatment of malignant tumors of the hematologic system. Despite the significant therapeutic effects of CAR-T, its toxic reactions, such as Cytokine Release Syndrome (CRS) and Immune Effector Cell-Associated Neurotoxicity Syndrome (ICANS), cannot be ignored since they can cause damage to multiple systems, including the cardiovascular system. We summarize biomarkers related to prediction, diagnosis, therapeutic efficacy, and prognosis, further exploring potential monitoring indicators for toxicity prevention. This review aims to summarize the effects of CAR-T therapy on the cardiovascular, hematologic, and nervous systems, as well as potential biomarkers, and to explore potential monitoring indicators for preventing toxicity, thereby providing references for clinical regulation and assessment of therapeutic effects.

Management of Toxicities Associated with BCMA, GPRC5D, and FcRH5-Targeting Bispecific Antibodies in Multiple Myeloma

PURPOSE OF REVIEW

The introduction of bispecific antibodies is one of the most significant recent advances in the treatment of relapsed/refractory multiple myeloma. This review will summarize the management of the toxicities associated with newly approved T cell-engaging bispecific antibodies and those which may be approved in the near future.

RECENT FINDINGS

Numerous trials have shown that bispecific antibodies can be both effective and tolerable when adverse events are properly managed. Cytokine release syndrome and increased infections are observed across all bispecific antibodies. Additional adverse events are target-specific, such as the more severe hypogammaglobulinemia and infections of BCMA bispecific antibodies and the dysgeusia, nail dystrophy, and skin changes of GPRC5D bispecific antibodies. Bispecific antibodies will surely become a mainstay of multiple myeloma therapy given their efficacy and accessibility. Their unique toxicities must be carefully considered and managed to ensure they are utilized safely.

Augmenting the landscape of chimeric antigen receptor T-cell therapy

INTRODUCTION

The inception of recombinant DNA technology and live cell genomic alteration have paved the path for the excellence of cell and gene therapies and often provided the first curative treatment for many indications. The approval of the first Chimeric Antigen Receptor (CAR) T-cell therapy was one of the breakthrough innovations that became the headline in 2017. Currently, the therapy is primarily restricted to a few nations, and the market is growing at a CAGR (current annual growth rate) of 11.6% (2022-2032), as opposed to the established bio-therapeutic market at a CAGR of 15.9% (2023-2030). The limited technology democratization is attributed to its autologous nature, lack of awareness, therapy inclusion criteria, high infrastructure cost, trained personnel, complex manufacturing processes, regulatory challenges, recurrence of the disease, and long-term follow-ups.

AREAS COVERED

This review discusses the vision and strategies focusing on the CAR T-cell therapy democratization with mitigation plans. Further, it also covers the strategies to leverage the mRNA-based CAR T platform for building an ecosystem to ensure availability, accessibility, and affordability to the community.

EXPERT OPINION

mRNA-guided CAR T cell therapy is a rapidly growing area wherein a collaborative approach among the stakeholders is needed for its success.

Chimeric Antigen Receptor T Cell with an Inducible Caspase-9 Suicide Gene Eradicates Uveal Melanoma Liver Metastases via B7-H3 Targeting

PURPOSE

Uveal melanoma (UM) is the most common intraocular malignant tumor. Despite successful treatment of the primary tumor, about 50% of patients will recur with systemic diseases for which there are no effective treatment strategies. Here we investigated the preclinical efficacy of a chimeric antigen receptor (CAR) T-cell-based immunotherapy targeting B7-H3.

EXPERIMENTAL DESIGN

B7-H3 expression on primary and metastatic human UM samples and cell lines was assessed by RNA sequencing, flow cytometry, and immunohistochemistry. Antitumor activity of CAR T cells targeting B7-H3 was tested in vitro with UM cell lines, patient-derived organotypic tumor spheroids from patients with metastatic UM, and in immunodeficient and humanized murine models.

RESULTS

B7-H3 is expressed at high levels in >95% UM tumor cells in vitro and in vivo. We generated a B7-H3 CAR with an inducible caspase-9 (iCas9) suicide gene controlled by the chemical inducer of dimerization AP1903, which effectively kills UM cells in vitro and eradicates UM liver metastases in murine models. Delivery of iCas9.B7-H3 CAR T cells in experimental models of UM liver metastases demonstrates a durable antitumor response, even upon tumor rechallenge or in the presence of a significant metastatic disease burden. We demonstrate effective iCas9.B7-H3 CAR T-cell elimination in vitro and in vivo in response to AP1903. Our studies demonstrate more effective tumor suppression with iCas9.B7-H3 CAR T cells as compared to a B7-H3-targeted humanized monoclonal antibody.

CONCLUSIONS

These studies support a phase I clinical trial with iCas9.B7-H3 CAR T cells to treat patients with metastatic UM.

Coagulation abnormalities associated with CAR-T-cell therapy in haematological malignancies: A review

Chimeric antigen receptor (CAR)-T-cell therapy has demonstrated considerable efficacy and safety in the treatment of patients with relapsed/refractory haematological malignancies. Owing to significant advances, CAR-T-cell therapeutic modality has undergone substantial shifts in its clinical application. Coagulation abnormalities, which are prevalent complications in CAR-T-cell therapy, can range in severity from simple abnormalities in coagulation parameters to serious haemorrhage or disseminated intravascular coagulation associated with life-threatening multiorgan dysfunction. Nonetheless, there is a lack of a comprehensive overview concerning the coagulation abnormalities associated with CAR-T-cell therapy. With an aim to attract heightened clinical focus and to enhance the safety of CAR-T-cell therapy, this review presents the characteristics of the coagulation abnormalities associated with CAR-T-cell therapy, including clinical manifestations, coagulation parameters, pathogenesis, risk factors and their influence on treatment efficacy in patients receiving CAR-T-cell infusion. Due to limited data, these conclusions may undergo changes as more experience accumulates.

Targeting TGFβ-activated kinase-1 activation in microglia reduces CAR T immune effector cell-associated neurotoxicity syndrome

Cancer immunotherapy with chimeric antigen receptor (CAR) T cells can cause immune effector cell-associated neurotoxicity syndrome (ICANS). However, the molecular mechanisms leading to ICANS are not well understood. Here we examined the role of microglia using mouse models and cohorts of individuals with ICANS. CD19-directed CAR (CAR19) T cell transfer in B cell lymphoma-bearing mice caused microglia activation and neurocognitive deficits. The TGFβ-activated kinase-1 (TAK1)-NF-κB-p38 MAPK pathway was activated in microglia after CAR19 T cell transfer. Pharmacological TAK1 inhibition or genetic Tak1 deletion in microglia using Cx3cr1CreER:Tak1fl/fl mice resulted in reduced microglia activation and improved neurocognitive activity. TAK1 inhibition allowed for potent CAR19-induced antilymphoma effects. Individuals with ICANS exhibited microglia activation in vivo when studied by translocator protein positron emission tomography, and imaging mass cytometry revealed a shift from resting to activated microglia. In summary, we prove a role for microglia in ICANS pathophysiology, identify the TAK1-NF-κB-p38 MAPK axis as a pathogenic signaling pathway and provide a rationale to test TAK1 inhibition in a clinical trial for ICANS prevention after CAR19 T cell-based cancer immunotherapy.

Cytokine release syndrome after CAR T-cell therapy for B-cell acute lymphoblastic leukemia in children and young adolescents: storms make trees take deeper roots

INTRODUCTION

Chimeric antigen receptor (CAR) T-cells have revolutionized cancer treatment, showing significant success, including treatment of pediatric B-cell acute lymphoblastic leukemia (B-ALL). Despite their efficacy, cytokine release syndrome (CRS) emerges as a common early adverse effect that can be life threatening in severe cases, resulting from the immune system's targeted activation against tumors.

AREAS COVERED

This review concentrates on CRS in children and young adults undergoing CAR T-cell therapy for B-ALL. It explores CRS pathophysiology, clinical presentation, and incidence, emphasizing the importance of a consensus definition and grading to homogenize the treatment according to the severity of symptoms. We will discuss the standard of care treatment of CRS but also novel approaches. We will highlight the importance of managing CRS without compromising the efficacy of immune cell activation against tumors.

EXPERT OPINION

As CAR T-cell therapy in pediatric B-ALL become increasingly available and used, optimal management of CRS becomes increasingly important. Early recognition and timely management has improved. Further information will aid us to identify optimal timing of tocilizumab and corticosteroids. Continued bench research coupled with clinical studies and biomarker discovery will allow for valuable insights into CRS pathophysiology and patient and/or cell-targeted treatments.

C-JUN overexpressing CAR-T cells in acute myeloid leukemia: preclinical characterization and phase I trial

Chimeric antigen receptor (CAR) T cells show suboptimal efficacy in acute myeloid leukemia (AML). We find that CAR T cells exposed to myeloid leukemia show impaired activation and cytolytic function, accompanied by impaired antigen receptor downstream calcium, ZAP70, ERK, and C-JUN signaling, compared to those exposed to B-cell leukemia. These defects are caused in part by the high expression of CD155 by AML. Overexpressing C-JUN, but not other antigen receptor downstream components, maximally restores anti-tumor function. C-JUN overexpression increases costimulatory molecules and cytokines through reinvigoration of ERK or transcriptional activation, independent of anti-exhaustion. We conduct an open-label, non-randomized, single-arm, phase I trial of C-JUN-overexpressing CAR-T in AML (NCT04835519) with safety and efficacy as primary and secondary endpoints, respectively. Of the four patients treated, one has grade 4 (dose-limiting toxicity) and three have grade 1-2 cytokine release syndrome. Two patients have no detectable bone marrow blasts and one patient has blast reduction after treatment. Thus, overexpressing C-JUN endows CAR-T efficacy in AML.

The Kinetics of Inflammation-Related Proteins and Cytokines in Children Undergoing CAR-T Cell Therapy-Are They Biomarkers of Therapy-Related Toxicities?

CD19-targeted CAR-T cell therapy has revolutionized the treatment of relapsed/refractory (r/r) pre-B acute lymphoblastic leukemia (ALL). However, it can be associated with acute toxicities related to immune activation, particularly cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Cytokines released from activated immune cells play a key role in their pathophysiology. This study was a prospective analysis of proinflammatory proteins and cytokines in children treated with tisagenlecleucel. Serial measurements of C-reactive protein, fibrinogen, ferritin, IL-6, IL-8, IL-10, IFNγ, and TNFα were taken before treatment and on consecutive days after infusion. The incidence of CRS was 77.8%, and the incidence of ICANS was 11.1%. No CRS of grade ≥ 3 was observed. All complications occurred within 14 days following infusion. Higher biomarker concentrations were found in children with CRS grade ≥ 2. Their levels were correlated with disease burden and CAR-T cell dose. While cytokine release syndrome was common, most cases were mild, primarily due to low disease burden before lymphodepleting chemotherapy (LDC). ICANS occurred less frequently but exhibited various clinical courses. None of the toxicities were fatal. All of the analyzed biomarkers rose within 14 days after CAR-T infusion, with most reaching their maximum around the third day following the procedure.

Riding the storm: managing cytokine-related toxicities in CAR-T cell therapy

The advent of chimeric antigen receptor T cells (CAR-T) has been a paradigm shift in cancer immunotherapeutics, with remarkable outcomes reported for a growing catalog of malignancies. While CAR-T are highly effective in multiple diseases, salvaging patients who were considered incurable, they have unique toxicities which can be life-threatening. Understanding the biology and risk factors for these toxicities has led to targeted treatment approaches which can mitigate them successfully. The three toxicities of particular interest are cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and immune effector cell-associated hemophagocytic lymphohistiocytosis (HLH)-like syndrome (IEC-HS). Each of these is characterized by cytokine storm and hyperinflammation; however, they differ mechanistically with regard to the cytokines and immune cells that drive the pathophysiology. We summarize the current state of the field of CAR-T-associated toxicities, focusing on underlying biology and how this informs toxicity management and prevention. We also highlight several emerging agents showing promise in preclinical models and the clinic. Many of these established and emerging agents do not appear to impact the anti-tumor function of CAR-T, opening the door to additional and wider CAR-T applications.

The crosstalk between immune cells and tumor pyroptosis: advancing cancer immunotherapy strategies

Pyroptosis is a cell death process characterized by cell swelling until membrane rupture and release of intracellular contents. As an effective tumor treatment strategy, inducing tumor cell pyroptosis has received widespread attention. In this process, the immune components within the tumor microenvironment play a key regulatory role. By regulating and altering the functions of immune cells such as cytotoxic T lymphocytes, natural killer cells, tumor-associated macrophages, and neutrophils, tumor cell pyroptosis can be induced. This article provides a comprehensive review of the molecular mechanisms of cell pyroptosis, the impact of the tumor immune microenvironment on tumor cell pyroptosis, and its mechanisms. It aims to gain an in-depth understanding of the communication between the tumor immune microenvironment and tumor cells, and to provide theoretical support for the development of new tumor immunotherapies.

Rescue of cardiac dysfunction during chemotherapy in acute myeloid leukaemia by blocking IL-1α

BACKGROUND AND AIMS

Patients with acute myeloid leukaemia (AML) suffer from severe myocardial injury during daunorubicin (DNR)-based chemotherapy and are at high risk of cardiac mortality. The crosstalk between tumour cells and cardiomyocytes might play an important role in chemotherapy-related cardiotoxicity, but this has yet to be demonstrated. This study aimed to identify its underlying mechanism and explore potential therapeutic targets.

METHODS

Cardiac tissues were harvested from an AML patient after DNR-based chemotherapy and were subjected to single-nucleus RNA sequencing. Cardiac metabolism and function were evaluated in AML mice after DNR treatment by using positron emission tomography, magnetic resonance imaging, and stable-isotope tracing metabolomics. Plasma cytokines were screened in AML mice after DNR treatment. Genetically modified mice and cell lines were used to validate the central role of the identified cytokine and explore its downstream effectors.

RESULTS

In the AML patient, disruption of cardiac metabolic homeostasis was associated with heart dysfunction after DNR-based chemotherapy. In AML mice, cardiac fatty acid utilization was attenuated, resulting in cardiac dysfunction after DNR treatment, but these phenotypes were not observed in similarly treated tumour-free mice. Furthermore, tumour cell-derived interleukin (IL)-1α was identified as a primary factor leading to DNR-induced cardiac dysfunction and administration of an anti-IL-1α neutralizing antibody could improve cardiac functions in AML mice after DNR treatment.

CONCLUSIONS

This study revealed that crosstalk between tumour cells and cardiomyocytes during chemotherapy could disturb cardiac energy metabolism and impair heart function. IL-1α neutralizing antibody treatment is a promising strategy for alleviating chemotherapy-induced cardiotoxicity in AML patients.

HLA reduction of human T cells facilitates generation of immunologically multicompatible cellular products

ABSTRACT

Adoptive cellular therapies have shown enormous potential but are complicated by personalization. Because of HLA mismatch, rejection of transferred T cells frequently occurs, compromising the T-cell graft's functionality. This obstacle has led to the development of HLA knock-out (KO) T cells as universal donor cells. Whether such editing directly affects T-cell functionality remains poorly understood. In addition, HLA KO T cells are susceptible to missing self-recognition through natural killer (NK) cells and lack of canonical HLA class I expression may represent a safety hazard. Engineering of noncanonical HLA molecules could counteract NK-cell recognition, but further complicates the generation of cell products. Here, we show that HLA KO does not alter T-cell functionality in vitro and in vivo. Although HLA KO abrogates allogeneic T-cell responses, it elicits NK-cell recognition. To circumvent this problem, we demonstrate that selective editing of individual HLA class I molecules in primary human T cells is possible. Such HLA reduction not only inhibits T-cell alloreactivity and NK-cell recognition simultaneously, but also preserves the T-cell graft's canonical HLA class I expression. In the presence of allogeneic T cells and NK cells, T cells with remaining expression of a single, matched HLA class I allele show improved functionality in vivo in comparison with conventional allogeneic T cells. Since reduction to only a few, most frequent HLA haplotypes would already be compatible with large shares of patient populations, this approach significantly extends the toolbox to generate broadly applicable cellular products.

An early regulatory mechanism of hyperinflammation by restricting monocyte contribution

Innate immune cells play a key role in inflammation as a source of pro-inflammatory cytokines. However, it remains unclear how innate immunity-mediated inflammation is fine-tuned to minimize tissue damage and assure the host's survival at the early phase of systemic inflammation. The results of this study with mouse models demonstrate that the supply of monocytes is restricted depending on the magnitude of inflammation. During the acute phase of severe inflammation, monocytes, but not neutrophils, were substantially reduced by apoptosis and the remaining monocytes were dysfunctional in the bone marrow. Monocyte-specific ablation of Casp3/7 prevented monocyte apoptosis but promoted monocyte necrosis in the bone marrow, leading to elevated levels of pro-inflammatory cytokines and the increased mortality of mice during systemic inflammation. Importantly, the limitation of monocyte supply was dependent on pro-inflammatory cytokines in vivo. Consistently, a reduction of monocytes was observed in the peripheral blood during cytokine-release syndrome (CRS) patients, a pathogen-unrelated systemic inflammation induced by chimeric antigen receptor-T cell (CAR-T cell) therapy. Thus, monocytes act as a safety valve to alleviate tissue damage caused by inflammation and ensure host survival, which may be responsible for a primitive immune-control mechanism that does not require intervention by acquired immunity.