Immune effector cell associated neurotoxicity syndrome in chimeric antigen receptor-T cell therapy

Exosomes in review: A new frontier in CAR-T cell therapies

Exosomes are extracellular vehicles that facilitate intra-cellular communication via transport of critical proteins and genetic material. Every exosome is intrinsically reflective of the cell from which it was derived and can even mimic effector functions of their parent cells. In recent years, with the success of CAR-T therapies, there has been growing interest in characterizing exosomes derived from CAR-T cells. CAR exosomes contain the same cytotoxic granules as their parent cells and have demonstrated significant anti-tumor activity in vitro and in animal models. Moreover, infusion of CAR exosomes in animal models did not generate cytokine release syndrome. Conversely, there are also novel bispecific antibodies which target tumor-derived exosomes in hopes of derailing immunosuppressive pathways mediated by exosomes produced from malignant cells. The two most promising examples include (a) BsE CD73 x EpCAM which binds and inhibits exosomal CD73 to suppress production of immunosuppressant adenosine and (b) BsE CD3 x PD-L1 which targets exosomal PD-L1 within the tumor microenvironment to guide cytotoxic T-cells towards tumor cells. As our understanding of exosome biology continues to evolve, opportunities for advances in cellular therapies will grow in tandem.

Human herpesvirus 6 (HHV-6) encephalitis secondary to chimeric antigen receptor (CAR)-T cell therapy

BACKGROUND

Human herpesvirus (HHV)-6 encephalitis secondary to chimeric antigen receptor (CAR)-T cell therapyis relatively rare in clinical practice and needs to be differentiated from immune effector cell-associatedneurotoxicity syndrome (ICANS).

METHODS

We retrospectively reported a case of HHV-6 encephalitis secondary to CAR-T cell therapy.

RESULTS

A male patient from China with diffuse large B-cell lymphoma underwent chimeric CAR-T cell therapy anddeveloped a generalized rash on the 8th day, followed by cognitive changes, memory loss, and disorientation onthe 14th day after CAR-T cell therapy. Initially, ICANS was suspected. A lumbar puncture was performed on the 18th day. The cerebrospinal fluid (CSF) analysis revealed slightly elevated protein levels and a high presence of HHV-6B sequences by mNGS. Brain MRI showed bilateral hippocampal abnormalities. The patient was ultimatelydiagnosed with HHV-6 encephalitis and treated with ganciclovir and dexamethasone. After one week of treatment,follow-up CSF analysis showed a reduction in HHV-6B sequences. The patient was discharged with improvedmemory and orientation.

CONCLUSION

HHV-6 encephalitis secondary to CAR-T cell therapy may be easily confused with ICANS. Timely andaggressive diagnostic procedures, such as mNGS of CSF and cranial imaging, along with prompt antiviral therapy,are crucial for improving patient outcomes.

New approach methodologies to assess wanted and unwanted drugs-induced immunostimulation

This review examines various classes of drugs, focusing on their therapeutic and adverse effects, particularly in relation to immunostimulation. We emphasize the potential of new approach methodologies (NAMs) to study both expected and unexpected immunostimulatory effects. By evaluating the modes of action of different immunostimulatory drugs, we aim to provide insights into effectively assessing unwanted immunostimulatory responses. The review begins by exploring drugs that stimulate the immune system-including immunostimulants, monoclonal antibodies, chemotherapeutics, and nucleic acid-based drugs-to outline NAMs that could be employed to evaluate immunostimulation.

The Development and Application of Bispecific Antibodies in B-Cell Non-Hodgkin Lymphoma

T-cell-engaging bispecific antibodies (BsAbs) are monoclonal antibodies that redirect the cytotoxic activity of T-cells to target malignant neoplasms. B-cell non-Hodgkin lymphoma (B-NHL) is a heterogenous group of aggressive and indolent malignancies with significant therapeutic challenges due to high relapse rates and limited options for relapsed/refractory disease. BsAbs function by simultaneously binding to CD3 on endogenous T-cells and a tumor-associated antigen, creating an immunologic synapse which results in the death of the target cell. The widespread T-cell activation that occurs with BsAb administration can result in cytokine release syndrome and neurological adverse events. Mosunetuzumab, epcoritamab, and glofitamab are CD20-targeting BsAbs that have demonstrated promising single-agent activity in both indolent and aggressive B-NHL. BsAbs are now being evaluated in combination with other anti-lymphoma agents and in earlier lines of treatment, and the results of ongoing clinical trials involving these agents have the potential to reshape the treatment landscape for B-NHL. In this review, we describe the structural features, clinical data, and toxicity profile associated with the BsAbs currently used to treat B-NHL and then discuss ongoing studies and future directions for this exciting new class of therapeutic agents.

Continuous Biosensing to Monitor Acute Systemic Inflammation, a Diagnostic Need for Therapeutic Guidance

Continuous monitoring of acute inflammation can become a very important next step for guiding therapeutic interventions in severely ill patients. This Perspective discusses the current medical need for patients with acute inflammatory diseases and the potential of continuous biosensing technologies. First, we discuss biomarkers that could help to monitor the state of a patient with acute systemic inflammation based on theoretical studies and empirical data. Then, based on the state of the art, we describe sensing strategies that could be applied for the continuous monitoring of acute inflammatory biomarkers, followed by challenges that must be overcome. Nanoswitch-based continuous biosensors enable suitable measurement frequencies but still lack sensitivity, while regeneration risks lower sensor reliability. Developments are still needed in bioreceptors and molecular architectures, regeneration techniques, combined with suitable sampling and sample pretreatment methods, for bringing continuous biosensing of inflammation closer to reality. Furthermore, collaborations between healthcare professionals and scientists, regulatory bodies, and biosensor engineers are needed for a successful translation of sensing technologies from the laboratory to clinical practice.

Siltuximab for chimeric antigen receptor T-cell therapy-related CRS and ICANS: a multicenter retrospective analysis

ABSTRACT

Chimeric antigen receptor T-cell (CAR-T) therapies are effective in many hematologic malignancies; however, adverse events including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) can affect a significant number of patients. Those who develop refractory CRS or ICANS have few treatment options. Siltuximab, a monoclonal antibody binding circulating interleukin-6, has been proposed to have clinical activity in both CRS and ICANS. We conducted a multicenter retrospective analysis of siltuximab treatment for CRS and ICANS after CAR-T therapy in a real-world cohort from 6 academic centers. Fifty-four patients were evaluated. Sixteen patients had CRS previously treated with tocilizumab and 17 patients had ICANS previously treated with steroids. Of the patients with CRS at the time of siltuximab, 75% had improvement in CRS grade. Of the patients with ICANS at the time of siltuximab, 60% had improvement in ICANS grade. To our knowledge, this is the largest cohort of patients treated with siltuximab for CRS and/or ICANS after CAR-T therapies. Siltuximab appeared to be effective for both CRS and ICANS, including previously treated toxicities. These data support the use of siltuximab in CRS and ICANS as well as provide rationale for future prospective studies.

The Role of Electroencephalography Following CAR-T Cell Therapy in Clinical Practice

Objectives:Neurotoxicity, encephalopathy, and seizures can occur following chimeric antigen receptor (CAR)-T cell therapy. Our aim was to assess what value electroencephalography (EEG) offers for people undergoing CAR-T treatment in clinical practice, including possible diagnostic, management, and prognostic roles. Methods: All patients developing CAR-T related neurotoxicity referred for EEG were eligible for inclusion. Reasons for EEG referral and qualitative EEG findings were analysed and reported. The relationship between objective quantitative EEG (QEEG) encephalopathy grade and clinical neurotoxicity (immune effector cell-associated neurotoxicity syndrome; ICANS) grade was determined. The prognostic ability of QEEG grade was assessed for survival and functional status. Results: Twenty-eight patients with 53 EEG recordings were included. Common reasons given on EEG referrals were possible seizure diagnosis (n = 38), reduced consciousness (n = 8), and superimposed cerebral infection (n = 4). Four focal seizures were detected on three (3/53; 5.7%) EEGs. There was a moderately positive correlation between QEEG grade and ICANS grade (r = + 0.41, p = .030). QEEG grade could not predict survival at 3 months (Area Under Curve; AUC = 0.673) or 6 months (AUC = 0.578), nor could it predict functional status at 1 month (r = + 0.40; p = .080), 3 months (r = + 0.19; p = .439), or time to return to baseline (r = + 0.32; p = .156). Conclusions: EEG was useful in seizure diagnosis. QEEG has a possible role as a specific biomarker of encephalopathy/neurotoxicity. EEG generated no tangible changes in patient management. QEEG was unable to prognosticate survival or functional status.

New developments in immunotherapy for SCLC

Small cell lung cancer (SCLC) is an aggressive form of neuroendocrine neoplasm known for its striking initial response to treatment, followed by fast relapse and refractoriness in response to additional lines of therapy. New advances in immunotherapy are paving the way for more effective treatment strategies and have promising results with early clinical trial data. While SCLC rarely harbors actionable mutations, the receptor DLL3 is extensively present in SCLC, making it a potential target for immunotherapy. Three emerging therapeutic options include bispecific T cell engagers targeting DLL3, chimeric antigen receptor T cells (CAR-T cells), and antibody-drug conjugates. Several phase II and phase III clinical trials for bispecific T cell engagers show promise. Additionally, the first CAR-T cell trials in humans for SCLC are currently underway.

Genetically stable multi-gene edited iPSCs-derived NK cells for enhanced cancer immunotherapy

Chimeric antigen receptor (CAR)-T cell treatment is an innovative drug with excellent therapeutic effects against B cell blood cancer. However, multiple side effects and ultra-high treatment costs must be overcome. Off-the-shelf CAR natural killer (NK) cells can be a good alternative to patient-specific CAR-T cells. The purpose of this study was to combine cellular reprogramming, gene editing, and differentiation technologies to produce full-off-the-shelf NK cells and to verify their efficacy and safety. Genetically stable universal and potent CAR (upCAR)-induced pluripotent stem cells (iPSCs) showed biallelic insertions and deletions in the coding sequence and no off-target effects. upCAR-NK cells showed a very high differentiation yield and in vitro proliferation, and freezing/thawing was possible. In addition, upCAR-NK cells secrete interferon-γ when they meet cancer cells, showing cytotoxic effects in vitro and in vivo. upCAR-NK cells show no obvious toxicity in vivo. In conclusion, this study developed genetically stable upCAR-iPSCs and upCAR-NK cell platform technologies that are less likely to have side effects and can be more economically developed for B cell blood cancer than CAR-T cells. In the future, this technology could be useful in developing a full-off-the-shelf CAR-NK cells anti-cancer immune cell therapy with low side effects, high efficacy, and a low price.

Earlier intrathecal dexamethasone effectively alleviate immune effector cell-associated neurotoxicity syndrome

Chimeric antigen receptor T cell (CAR-T) therapy is effective in treating relapsed/refractory B-cell acute lymphoblastic leukemia (R/R B-ALL). However, the side effects of immune effector cell-associated neurotoxicity syndrome (ICANS) remain a problem. The current frontline therapies for ICANS include steroids and supportive care. For the steroid-refractory and severe ICANS, several studies have reported excellent efficacy of intrathecal (IT) corticosteroids alone or in combination with chemotherapy. However, whether patients can benefit from IT dexamethasone (dex) before grade 3 or refractory ICANS remains unclear. In this study, the patients with ICANS (≥1) after CAR-T cell therapy were assigned to the IT group and non-IT group. Clinical information, laboratory parameters, and serum cytokine levels were analyzed. A significant and rapid reduction in inflammatory cytokines and biomarkers was observed after 24 h of IT dex treatment. With IT dex, 83.3 % (15/18) of patients recovered from neurotoxicity. Moreover, this option significantly shortens the recovery time of ICANS without affecting the efficacy of CAR-T cell therapy. Earlier initiation of IT dex is the optimal management of ICANS resulting from CAR-T cell therapy, but larger sample studies are needed to determine its efficacy in these settings.

EGFRVIII and EGFR targeted chimeric antigen receptor T cell therapy in glioblastoma

Glioblastoma is the most common primary brain tumor. Although there have been significant advances in surgical techniques, chemo and immunotherapies, and radiation therapy, outcomes continue to be devastating for these patients with minimal improvements in survival. Chimeric antigen receptor T cell therapy is a revolutionary approach that is a new pillar in the treatment of cancer. CAR T cell therapy has produced remarkable results in hematological malignancies; however, multiple limitations currently prevent it from being a first-line therapy, especially for solid tumors. Epidermal growth factor receptor is classically amplified in glioblastoma, and a variant, EGFR variant III, is expressed on glioblastoma, making it an exciting potential target for CAR T cell therapy. Although preclinical has exciting potential, clinical data has been heterogeneous. In this review, we assess the state of field of EGFR-targeted CAR T cells.

Targeting B-cell maturation antigen for treatment and monitoring of relapsed/refractory multiple myeloma patients: a comprehensive review

Despite major therapeutic advancements in recent years, multiple myeloma (MM) remains an incurable disease with nearly all patients experiencing relapsed and refractory disease over the course of treatment. Extending the duration and durability of clinical responses will necessitate the development of therapeutics with novel targets that are capable of robustly and specifically eliminating myeloma cells. B-cell maturation antigen (BCMA) is a membrane-bound protein expressed predominantly on malignant plasma cells and has recently been the target of several novel therapeutics to treat MM patients. This review will focus on recently approved and currently in development agents that target this protein, including bispecific antibodies, antibody-drug conjugates, and chimeric antigen receptor T-cell therapies. In addition, this protein also serves as a novel serum biomarker to predict outcomes and monitor disease status for MM patients; the studies demonstrating this use of BCMA will be discussed in detail.

The method for assessing the specificity of developing CAR therapies

The effectiveness of antitumor chimeric antigen receptor (CAR) therapy mainly dealt with an elevated sensitivity of CAR cells to target cells. However, CAR therapies are associated with nonspecific side effects: on-target off-tumor toxicity. Sensitivity and specificity of CAR cells are the most important properties of the recognition process of target cells among other cells. Current developments are mainly concentrated on exploring molecular biology methods for designing CAR cells with the highest sensitivity, while the problem of the CAR cell specificity is rarely considered. For the assessment of CAR cell specificity, we suggest that, in addition to an elevated level of CAR-antigen affinity, the ability of CARs for clustering should be taken into account. We assume that the CAR cell cytotoxicity is determined by CAR clustering. The latter is treated within the framework of nucleation theory. The master equation for the probability of CAR cell cytotoxicity is derived. The size of a critical CAR cluster is found to be one of two most essential parameters. The conditions for necessary sensitivity and sufficient specificity are explored. Relevant parametric diagrams are derived. Possible applications of the method for assessing the specificity of developing CAR therapies are discussed.

Management of bone disease with concurrent chimeric antigen receptor T-cell therapy for multiple myeloma

In the intricate landscape of multiple myeloma, a hematologic malignancy of plasma cells, bone disease presents a pivotal and often debilitating complication. The emergence of Chimeric Antigen Receptor T-cell (CAR-T) therapy has marked a pivotal shift in the therapeutic landscape, offering novel avenues for the management of MM, particularly for those with relapsed or refractory disease. This innovative treatment modality not only targets malignant cells with precision but also influences the bone microenvironment, presenting both challenges and opportunities in patient care. In this comprehensive review, we aim to examine the multifaceted aspects of bone disease in patients with multiple myeloma and concurrent CAR-T therapy, highlighting its clinical ramifications and the latest advancements in diagnostic modalities and therapeutic interventions. The article aims to synthesize current understanding of the interplay between myeloma cells, CAR-T cells, and the bone microenvironment in the context of current treatment strategies in this challenging and unique patient population.

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.

Safety outcomes of teclistamab accelerated dose escalation

INTRODUCTION

Teclistamab, a bispecific T-cell engaging antibody targeting B-cell maturation antigen (BCMA), is indicated for the treatment of relapsed or refractory multiple myeloma after at least four lines of therapy. It has boxed warnings for life threatening cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). To mitigate these risks, teclistamab is initiated using step-up doses. This article examines safety event rates following the implementation of a 2-day separation between step-up doses at one institution to streamline patient care.

METHODS

This was a retrospective, single-center study encompassing all patients who received teclistamab within a 1-year period. The primary endpoint was the overall incidence of CRS and ICANS. Secondary endpoints included hospital length of stay, hematological toxicities, infection rates, among other adverse events.

RESULTS

A total of 27 patients were included in the analysis and stratified into accelerated (days 1,3,5) or standard (days 1,4,7) dosing groups. CRS occurred in 48% (11) of patients for the accelerated dosing and 50% (2) for the standard dosing group. ICANS was seen in 17% (4) of patients in the accelerated dosing group and none in the standard dosing group. Average length of stay in the accelerated dose was 7.6 days versus 9.2 days in the standard dose group.

CONCLUSION

Accelerated dose escalation of teclistamab yielded safety event rates comparable to those in the literature. These findings may support outpatient administration for teclistamab. Accelerated dose escalation strategy allowed for the optimization of hospitalization and resources.

Universal CAR 2.0 to overcome current limitations in CAR therapy

Chimeric antigen receptor (CAR) T cell therapy has effectively complemented the treatment of advanced relapsed and refractory hematological cancers. The remarkable achievements of CD19- and BCMA-CAR T therapies have raised high expectations within the fields of hematology and oncology. These groundbreaking successes are propelling a collective aspiration to extend the reach of CAR therapies beyond B-lineage malignancies. Advanced CAR technologies have created a momentum to surmount the limitations of conventional CAR concepts. Most importantly, innovations that enable combinatorial targeting to address target antigen heterogeneity, using versatile adapter CAR concepts in conjunction with recent transformative next-generation CAR design, offer the promise to overcome both the bottleneck associated with CAR manufacturing and patient-individualized treatment regimens. In this comprehensive review, we delineate the fundamental prerequisites, navigate through pivotal challenges, and elucidate strategic approaches, all aimed at paving the way for the future establishment of multitargeted immunotherapies using universal CAR technologies.

Deleting the mitochondrial respiration negative regulator MCJ enhances the efficacy of CD8+ T cell adoptive therapies in pre-clinical studies

Mitochondrial respiration is essential for the survival and function of T cells used in adoptive cellular therapies. However, strategies that specifically enhance mitochondrial respiration to promote T cell function remain limited. Here, we investigate methylation-controlled J protein (MCJ), an endogenous negative regulator of mitochondrial complex I expressed in CD8 cells, as a target for improving the efficacy of adoptive T cell therapies. We demonstrate that MCJ inhibits mitochondrial respiration in murine CD8+ CAR-T cells and that deletion of MCJ increases their in vitro and in vivo efficacy against murine B cell leukaemia. Similarly, MCJ deletion in ovalbumin (OVA)-specific CD8+ T cells also increases their efficacy against established OVA-expressing melanoma tumors in vivo. Furthermore, we show for the first time that MCJ is expressed in human CD8 cells and that the level of MCJ expression correlates with the functional activity of CD8+ CAR-T cells. Silencing MCJ expression in human CD8 CAR-T cells increases their mitochondrial metabolism and enhances their anti-tumor activity. Thus, targeting MCJ may represent a potential therapeutic strategy to increase mitochondrial metabolism and improve the efficacy of adoptive T cell therapies.

Genetic Susceptibility in Endothelial Injury Syndromes after Hematopoietic Cell Transplantation and Other Cellular Therapies: Climbing a Steep Hill

Hematopoietic stem cell transplantation (HSCT) remains a cornerstone in the management of patients with hematological malignancies. Endothelial injury syndromes, such as HSCT-associated thrombotic microangiopathy (HSCT-TMA), veno-occlusive disease/sinusoidal obstruction syndrome (SOS/VOD), and capillary leak syndrome (CLS), constitute complications after HSCT. Moreover, endothelial damage is prevalent after immunotherapy with chimeric antigen receptor-T (CAR-T) and can be manifested with cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS). Our literature review aims to investigate the genetic susceptibility in endothelial injury syndromes after HSCT and CAR-T cell therapy. Variations in complement pathway- and endothelial function-related genes have been associated with the development of HSCT-TMA. In these genes, CFHR5, CFHR1, CFHR3, CFI, ADAMTS13, CFB, C3, C4, C5, and MASP1 are included. Thus, patients with these variations might have a predisposition to complement activation, which is also exaggerated by other factors (such as acute graft-versus-host disease, infections, and calcineurin inhibitors). Few studies have examined the genetic susceptibility to SOS/VOD syndrome, and the implicated genes include CFH, methylenetetrahydrofolate reductase, and heparinase. Finally, specific mutations have been associated with the onset of CRS (PFKFB4, CX3CR1) and ICANS (PPM1D, DNMT3A, TE2, ASXL1). More research is essential in this field to achieve better outcomes for our patients.

Charting new paradigms for CAR-T cell therapy beyond current Achilles heels

Chimeric antigen receptor-T (CAR-T) cell therapy has made remarkable strides in treating hematological malignancies. However, the widespread adoption of CAR-T cell therapy is hindered by several challenges. These include concerns about the long-term and complex manufacturing process, as well as efficacy factors such as tumor antigen escape, CAR-T cell exhaustion, and the immunosuppressive tumor microenvironment. Additionally, safety issues like the risk of secondary cancers post-treatment, on-target off-tumor toxicity, and immune effector responses triggered by CAR-T cells are significant considerations. To address these obstacles, researchers have explored various strategies, including allogeneic universal CAR-T cell development, infusion of non-activated quiescent T cells within a 24-hour period, and in vivo induction of CAR-T cells. This review comprehensively examines the clinical challenges of CAR-T cell therapy and outlines strategies to overcome them, aiming to chart pathways beyond its current Achilles heels.

CAR-T Cell Therapy in Ovarian Cancer: Where Are We Now?

The success of chimeric antigen receptor T-cell (CAR-T) therapies in the treatment of hematologic malignancies has led to the investigation of their potential in the treatment of solid tumors, including ovarian cancer. While the immunosuppressive microenvironment of ovarian cancer has been a barrier in their implementation, several early phase clinical trials are currently evaluating CAR-T cell therapies targeting mesothelin, folate receptor a, HER2, MUC16, and B7H3. Ongoing challenges include cytokine-associated and "on-target, off-tumor" toxicities, while most common adverse events include cytokine release syndrome, hemophagocytic lymphohistiocytosis/macrophage activation-like syndrome (HLH/MAS), and neurotoxicity. In the present review, we summarize the current status of CAR-T therapy in ovarian cancer and discuss future directions.

Enhancing the safety of CAR-T cell therapy: Synthetic genetic switch for spatiotemporal control

Chimeric antigen receptor T (CAR-T) cell therapy is a promising and precise targeted therapy for cancer that has demonstrated notable potential in clinical applications. However, severe adverse effects limit the clinical application of this therapy and are mainly caused by uncontrollable activation of CAR-T cells, including excessive immune response activation due to unregulated CAR-T cell action time, as well as toxicity resulting from improper spatial localization. Therefore, to enhance controllability and safety, a control module for CAR-T cells is proposed. Synthetic biology based on genetic engineering techniques is being used to construct artificial cells or organisms for specific purposes. This approach has been explored in recent years as a means of achieving controllability in CAR-T cell therapy. In this review, we summarize the recent advances in synthetic biology methods used to address the major adverse effects of CAR-T cell therapy in both the temporal and spatial dimensions.

Current and emerging pharmacotherapies for cytokine release syndrome, neurotoxicity, and hemophagocytic lymphohistiocytosis-like syndrome due to CAR T cell therapy

INTRODUCTION

Chimeric antigen receptor (CAR) T cells have revolutionized the treatment of multiple hematologic malignancies. Engineered cellular therapies now offer similar hope to transform the management of solid tumors and autoimmune diseases. However, toxicities can be serious and often require hospitalization.

AREAS COVERED

We review the two chief toxicities of CAR T therapy, cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), and the rarer immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome. We discuss treatment paradigms and promising future pharmacologic strategies. Literature and therapies reviewed were identified by PubMed search, cited references therein, and review of registered trials.

EXPERT OPINION

Management of CRS and ICANS has improved, aided by consensus definitions and guidelines that facilitate recognition and timely intervention. Further data will define optimal timing of tocilizumab and corticosteroids, current foundations of management. Pathophysiologic understanding has inspired off-label use of IL-1 receptor antagonism, IFNγ and IL-6 neutralizing antibodies, and janus kinase inhibitors, with data emerging from ongoing clinical trials. Further strategies to reduce toxicities include novel pharmacologic targets and safety features engineered into CAR T cells themselves. As these potentially curative therapies are used earlier in oncologic therapy and even in non-oncologic indications, effective accessible strategies to manage toxicities are critical.

Brief research report: in-depth immunophenotyping reveals stability of CD19 CAR T-cells over time

Variability or stability might have an impact on treatment success and toxicity of CD19 CAR T-cells. We conducted a prospective observational study of 12 patients treated with Tisagenlecleucel for CD19+ B-cell malignancies. Using a 31-color spectral flow cytometry panel, we analyzed differentiation stages and exhaustion markers of CAR T-cell subsets prior to CAR T-cell infusion and longitudinally during 6 months of follow-up. The majority of activation markers on CAR T-cells showed stable expression patterns over time and were not associated with response to therapy or toxicity. Unsupervised cluster analysis revealed an immune signature of CAR T-cell products associated with the development of immune cell-associated neurotoxicity syndrome. Warranting validation in an independent patient cohort, in-depth phenotyping of CAR T-cell products as well as longitudinal monitoring post cell transfer might become a valuable tool to increase efficacy and safety of CAR T-cell therapy.

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

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

Prophylactic use of interleukin 6 monoclonal antibody can reduce CRS response of CAR-T cell therapy

Background

Chimeric antigen receptor T (CAR-T) cell immunotherapy is becoming one of the most promising treatments for hematological malignancies, however, complications such as cytokine release syndrome (CRS) seriously threaten the lives of patients. Interleukin 6(IL-6) monoclonal antibody is the common and useful treatment of CRS, however, it is not clear whether prophylactic use IL-6 monoclonal antibody before CAR-T therapy can reduce the incidence of CRS.

Purpose

This study aims to systematically evaluate whether the prophylactic use of IL-6 monoclonal antibody can reduce the incidence of CRS.

Data sources and methods

We searched the PubMed, Embase, web of Science, and Cochrane Library databases for studies that reported the prophylactic use of IL-6 monoclonal antibody in the treatment of CRS-related complications of CAR-T cell immunotherapy before December 2022. The literature is screened according to the established inclusion and exclusion criteria, relevant data are extracted, and the quality of the literature is evaluated using the scale Cochrane bias risk assessment tool, and the Review Manager 5.3 is used to draw for related charts. Since the two experimental data only provide the median, the maximum and minimum values of the data, the mean and standard (Standard Deviation, SD) are calculated by this document Delai, and finally use Review Manager for data processing, and STATA software for supplementation.

Results

A total of 2 trials with a total of 37 participants were included in this study. Meta-analysis showed that compared with no use of IL-6 monoclonal antibody to prevent CRS, IL-6 monoclonal antibody was given to patients at 8 mg/kg one hour before CAR-T cell infusion, which reduced the incidence of CRS [RR: 0.41 95% confidence interval (0.20, 0.86) I[2] = 0.0% P = 0.338 z = -2.369 (p = 0.018)]. In subgroup analysis, compared with those who did not use IL-6 monoclonal antibody to prevent CRS, IL-6 monoclonal antibody was given to patients at 8 mg/kg one hour before CAR-T cell infusion, which reduced lactate dehydrogenase (LDH)[MD: -617.21, 95% confidence interval (-1104.41, -130.01) I[2] = 0% P = 0.88 Z = 2.48 (P = 0.01)], prophylactic use of IL-6 monoclonal antibody has a significant effect on reducing peak C-reactive protein (CRP) after CAR-T therapy [MD: -11.58, 95% confidence interval (-15.28, -7.88) I[2] = 0.0% P = 0.73 z = 6.14 (p < 0.00001)].

Conclusion

The prophylactic use of IL-6 monoclonal antibody can significantly reduce the incidence of CRS complications after CAR-T therapy, can also reduce LDH vaule and peak CRP vaule after CAR-T therapy.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023487662, identifier CRD42023487662.

Chimeric antigen receptor T cells for acute myeloid leukemia

The use of T cells expressing chimeric antigen receptors (CARs) that can target and eliminate cancer cells has revolutionized the treatment of B-cell malignancies. In contrast, CAR T cells have not yet become a routine treatment for myeloid malignancies such as acute myeloid leukemia (AML) or myeloproliferative neoplasms (MPNs). For these disease entities, allogeneic hematopoietic cell transplantation (allo-HCT) relying on polyclonal allo-reactive T cells is still the major cellular immunotherapy used in clinical routine. Here, we discuss major hurdles of CAR T-cell therapy for myeloid malignancies and novel approaches to enhance their efficacy and reduce toxicity. Heterogeneity of the malignant myeloid clone, CAR T-cell induced toxicity against normal hematopoietic cells, lack of long-term CAR T-cell persistence, and loss or downregulation of targetable antigens on myeloid cells are obstacles for successful CAR T cells therapy against AML and MPNs. Strategies to overcome these hurdles include pharmacological interventions, for example, demethylating therapy to increase target antigen expression, multi-targeted CAR T cells, and gene-therapy based approaches that delete the CAR target antigen in the hematopoietic cells of the recipient to protect them from CAR-induced myelotoxicity. Most of these approaches are still in preclinical testing but may reach the clinic in the coming years. In summary, we report on barriers to CAR T-cell use against AML and novel therapeutic strategies to overcome these challenges, with the goal of clinical treatment of myeloid malignancies with CAR T cells.

Early and Late Toxicities of Chimeric Antigen Receptor T-Cells

As chimeric antigen receptor (CAR) T-cell therapy is increasingly integrated into clinical practice across a range of malignancies, identifying and treating inflammatory toxicities will be vital to success. Early experiences with CD19-targeted CAR T-cell therapy identified cytokine release syndrome and neurotoxicity as key acute toxicities and led to unified initiatives to mitigate the influence of these complications. In this section, we provide an update on the current state of CAR T-cell-related toxicities, with an emphasis on emerging acute toxicities affecting additional organ systems and considerations for delayed toxicities and late effects.

Advancing the frontiers of adaptive cell therapy: A transformative mechanistic journey from preclinical to clinical settings

Although the concept of using the patient's immune system to combat cancer has been around for a while, it is only in recent times that substantial progress has been achieved in this field. Over the last ten years, there has been a significant advancement in the treatment of cancer through immune checkpoint blockade. This treatment has been approved for multiple types of tumors. Another approach to modifying the immune system to detect tumor cells and fight them off is adaptive cell therapy (ACT). This therapy involves using T cells that have been modified with either T cell receptors (TCR) or chimeric antigen receptors (CAR) to target the tumor cells. ACT has demonstrated encouraging outcomes in different types of tumors, and clinical trials are currently underway worldwide to enhance this form of treatment. This review focuses on the advancements that have been made in ACT from preclinical to clinical settings till now.

Fine-tuning the antigen sensitivity of CAR T cells: emerging strategies and current challenges

Chimeric antigen receptor (CAR) T cells are "living drugs" that specifically recognize their target antigen through an antibody-derived binding domain resulting in T cell activation, expansion, and destruction of cognate target cells. The FDA/EMA approval of CAR T cells for the treatment of B cell malignancies established CAR T cell therapy as an emerging pillar of modern immunotherapy. However, nearly every second patient undergoing CAR T cell therapy is suffering from disease relapse within the first two years which is thought to be due to downregulation or loss of the CAR target antigen on cancer cells, along with decreased functional capacities known as T cell exhaustion. Antigen downregulation below CAR activation threshold leaves the T cell silent, rendering CAR T cell therapy ineffective. With the application of CAR T cells for the treatment of a growing number of malignant diseases, particularly solid tumors, there is a need for augmenting CAR sensitivity to target antigen present at low densities on cancer cells. Here, we discuss upcoming strategies and current challenges in designing CARs for recognition of antigen low cancer cells, aiming at augmenting sensitivity and finally therapeutic efficacy while reducing the risk of tumor relapse.

CD44v6 specific CAR-NK cells for targeted immunotherapy of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a major challenge for current therapies. CAR-T cells have shown promising results in blood cancers, however, their effectiveness against solid tumors remains a hurdle. Recently, CD44v6-directed CAR-T cells demonstrated efficacy in controlling tumor growth in multiple myeloma and solid tumors such as HNSCC, lung and ovarian adenocarcinomas. Apart from CAR-T cells, CAR-NK cells offer a safe and allogenic alternative to autologous CAR-T cell therapy. In this paper, we investigated the capacity of CAR-NK cells redirected against CD44v6 to execute cytotoxicity against HNSCC. Anti-CD44v6 CAR-NK cells were generated from healthy donor peripheral blood-derived NK cells using gamma retroviral vectors (gRVs). The NK cell transduction was optimized by exploring virus envelope proteins derived from the baboon endogenous virus envelope (BaEV), feline leukemia virus (FeLV, termed RD114-TR) and gibbon ape leukemia virus (GaLV), respectively. BaEV pseudotyped gRVs induced the highest transduction rate compared to RD114-TR and GaLV envelopes as measured by EGFP and surface CAR expression of transduced NK cells. CAR-NK cells showed a two- to threefold increase in killing efficacy against various HNSCC cell lines compared to unmodified, cytokine-expanded primary NK cells. Anti-CD44v6 CAR-NK cells were effective in eliminating tumor cell lines with high and low CD44v6 expression levels. Overall, the improved cytotoxicity of CAR-NK cells holds promise for a therapeutic option for the treatment of HNSCC. However, further preclinical trials are necessary to test in vivo efficacy and safety, as well to optimize the treatment regimen of anti-CD44v6 CAR-NK cells against solid tumors.

The shifting roles and toxicities of cellular therapies in B-cell malignancies

Cellular therapies provide a curative-intent option for patients with relapsedand refractory lymphomas. Current options including high dose chemotherapyfollowed by autologous or allogeneic hematopoietic stem cell transplantation or CD19 chimericantigen receptor T-cell (CART) therapy. The indication varies according to lymphoma sub-type and line oftherapy. The sequencing of these therapies and their use in second-line orlater settings to manage these diseases is undergoing significant changes, withCD19 CAR T becoming a preferred option for relapsed aggressive B-cell lymphoma.The mechanism of both therapies causes significant yet distinctlymphodepletion, infectious, and inflammatory toxicities. The resulting patternand timing of immune reconstitution helps guide risk-mitigating strategies,revaccination, and infectious prophylaxis. In this review, we discuss theindication, efficacy, toxicity and immune reconstitution of autologoushematopoietic stem cell transplantation and CAR T therapy for use in thetreatment of lymphoma.

Outcomes of Chimeric Antigen Receptor (CAR) T-Cell Therapy in Patients with Large B-Cell Lymphoma (LBCL): A Single-Institution Experience

Chimeric antigen receptor T-cell (CAR T-cell) therapy has revolutionized the treatment of relapsed/refractory (R/R) large B-cell lymphoma (LBCL). We describe the real-world baseline characteristics, efficacy, safety, and post-relapse outcomes of adult patients with R/R LBCL who received CAR T-cell therapy at the University of California San Diego. A total of 66 patients with LBCL were treated with tisagenlecleucel or axicabtagene ciloleucel. The median age was 59.5, and 21% were over 70 years old. Additionally, 20% of the patients had an Eastern Cooperative Oncology Group (ECOG) performance score of ≥2. Cytokine release syndrome incidence was 88%; immune effector cell-associated neurotoxicity syndrome incidence was 56%. All-grade infection occurred in 48% of patients and in 79% of patients > 70 years old. Complete response (CR) was achieved in 53% and partial response in 14%. Median progression-free survival (PFS) was 10.3 months; median overall survival (OS) was 28.4 months. Patients who relapsed post-CAR T-cell therapy had poor outcomes, with a median OS2 of 4.8 months. Upon multivariate analysis, both ECOG (HR 2.65, 95% CI: 1.30-5.41; p = 0.007) and ≥2 sites of extranodal involvement (HR 2.22, 95% CI: 1.15-4.31; p = 0.018) were significant predictors of PFS. Twenty-six patients were R/R to CAR T-cell therapy; six patients were in remission at the time of data cut off, one of whom received allogeneic transplant. Overall, older patients can safely undergo CAR T-cell therapy, despite the increased risk of all-grade infection. In our cohort, ECOG performance score and ≥2 sites of extranodal disease are significant predictors of PFS.

A Pharmacovigilance Study on the Safety of Axicabtagene Ciloleucel Based on Spontaneous Reports from the EudraVigilance Database

During pre-approval clinical trials, the safety of axi-cel, a second-generation CAR-T-cell therapy directed against CD19, which dramatically improved the prognosis of intractable B-cell lymphomas, has been investigated only in about 400 patients. Therefore, additional information on this issue is urgently needed. In the present paper, we evaluated the 2905 ICSRs with axi-cel as the suspected drug that had been uploaded in the EudraVigilance database from 1 January 2018 to 31 December 2022. About 80% of the reported adverse events were serious, and about 20% of them did not fully resolve or caused death. The adverse events most-frequently reported were Nervous system disorders (25.6%) and, among them, immune-effector-cell-associated neurotoxicity syndrome, followed by Immune system disorders (23.1%), General disorders and administration site conditions (12.0%), Blood and lymphatic system disorders (7.2%), and Infections and infestations (5.8%). Disproportionality analysis showed that the frequency of reported adverse events related to the nervous system was higher with axi-cel than with the other approved CAR-T-cells, except brexu-cel. In conclusion, real-world pharmacovigilance data showed that nervous system and immune system disorders are the adverse events most reported in axi-cel-related ICSRs and suggest that axi-cel could be more neurotoxic than other CAR-T-cells.

CAR-T State of the Art and Future Challenges, A Regulatory Perspective

This review is an outlook on CAR-T development up to the beginning of 2023, with a special focus on the European landscape and its regulatory field, highlighting the main features and limitations affecting this innovative therapy in cancer treatment. We analysed the current state of the art in the EU and set out a showcase of the field's potential advancements in the coming years. For this analysis, the data used came from the available scientific literature as well as from the European Medicines Agency and from clinical trial databases. The latter were investigated to query the studies on CAR-Ts that are active and/or relevant to the review process. As of this writing, CAR-Ts have started to move past the "ceiling" of third-line treatment with positive results in comparison trials with the Standard of Care (SoC). One such example is the trial Zuma-7 (NCT03391466), which resulted in approval of CAR-T products (Yescarta™) for second-line treatment, a crucial achievement for the field which can increase the use of this type of therapy. Despite exciting results in clinical trials, limitations are still many: they regard access, production, duration of response, resistance, safety, overall efficacy, and cost mitigation strategies. Nonetheless, CAR-T constructs are becoming more diverse, and the technology is starting to produce some remarkable results in treating diseases other than cancer.

Toxicity Profile of Chimeric Antigen Receptor T-Cell and Bispecific Antibody Therapies in Multiple Myeloma: Pathogenesis, Prevention and Management

Multiple myeloma is the second-most common hematologic malignancy in adults worldwide. Despite ongoing advancement in therapeutic modalities, it remains an incurable disease with a 5-year survival rate of approximately 50%. The recent development and introduction of anti-BCMA immunotherapies into clinical practice, including chimeric antigen receptor T-cell (CAR-T) therapies and bispecific antibodies, has radically shifted the treatment paradigm. However, despite the promising potential of these therapies for broader application, frequent and significant adverse effects have been reported, both in short- and in long-term settings, requiring increasing awareness and vigilance in the treating team, close monitoring, and prompt interventions with a multidisciplinary approach. In this review, we will discuss the toxicities associated with CAR-T cell and bispecific antibody therapies, focusing on results from major clinical studies and real-world observations. In addition, we will emphasize on effective strategies for prevention, monitoring and management, and provide expert recommendations.

Prevention and management of adverse events during treatment with bispecific antibodies and CAR T cells in multiple myeloma: a consensus report of the European Myeloma Network

T-cell redirecting bispecific antibodies (BsAbs) and chimeric antigen receptor T cells (CAR T cells) have revolutionised multiple myeloma therapy, but adverse events such as cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome (ICANS), cytopenias, hypogammaglobulinaemia, and infections are common. This Policy Review presents a consensus from the European Myeloma Network on the prevention and management of these adverse events. Recommended measures include premedication, frequent assessing for symptoms and severity of cytokine release syndrome, step-up dosing for several BsAbs and some CAR T-cell therapies; corticosteroids; and tocilizumab in the case of cytokine release syndrome. Other anti-IL-6 drugs, high-dose corticosteroids, and anakinra might be considered in refractory cases. ICANS often arises concomitantly with cytokine release syndrome. Glucocorticosteroids in increasing doses are recommended if needed, as well as anakinra if the response is inadequate, and anticonvulsants if convulsions occur. Preventive measures against infections include antiviral and antibacterial drugs and administration of immunoglobulins. Treatment of infections and other complications is also addressed.

Neoantigen-directed therapeutics in the clinic: where are we?

In the past decade, immune checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR) T cell therapy have brought immunotherapy to the forefront of cancer treatment; however, only subsets of patients benefit from current approaches. Neoantigen-driven therapeutics specifically redirect the immune system of the patient to enable or reinduce its ability to recognize and eliminate cancer cells. The tumor specificity of this strategy spares healthy and normal cells from being attacked. Consistent with this concept, initial clinical trials have demonstrated the feasibility, safety, and immunogenicity of neoantigen-directed personalized vaccines. We review neoantigen-driven therapy strategies as well as their promise and clinical successes to date.

IRF4 downregulation improves sensitivity and endurance of CAR T cell functional capacities

Chimeric antigen receptor (CAR) modified T cells can induce complete remissions in patients with advanced hematological malignancies. Nevertheless, the efficacy is mostly transient and remains so far poor in the treatment of solid tumors. Crucial barriers to long-term CAR T cell success encompass loss of functional capacities known as "exhaustion", among others. To extend CAR T cell functionality, we reduced interferon regulatory factor 4 (IRF4) levels in CAR T cells using a one-vector system encoding a specific short-hairpin (sh) RNA along with constitutive CAR expression. At baseline, CAR T cells with downregulated IRF4 showed equal cytotoxicity and cytokine release compared to conventional CAR T cells. However, under conditions of repetitive antigen encounter, IRF4^low CAR T cells displayed enhanced functionality with superior cancer cell control in the long-term compared with conventional CAR T cells. Mechanistically, the downregulation of IRF4 in CAR T cells resulted in prolonged functional capacities and upregulation of CD27. Moreover, IRF4^low CAR T cells were more sensitive to cancer cells with low levels of target antigen. Overall, IRF4 downregulation capacitates CAR T cells to recognize and respond to target cells with improved sensitivity and endurance.

CAR T-cell-associated neurotoxicity in central nervous system hematologic disease: Is it still a concern?

Chimeric antigen receptor (CAR) T-cell systemic immunotherapy has revolutionized how clinicians treat several refractory and relapsed hematologic malignancies. Due to its peculiar mechanism of action, CAR T-cell-based therapy has enlarged the spectrum of neurological toxicities. CAR T-cell-associated neurotoxicity-initially defined as CAR T-cell-related encephalopathy syndrome (CRES) and currently coined within the acronym ICANS (immune effector cell-associated neurotoxicity syndrome)-is perhaps the most concerning toxicity of CAR T-cell therapy. Importantly, hematologic malignancies (especially lymphoid malignancies) may originate in or spread to the central nervous system (CNS) in the form of parenchymal and/or meningeal disease. Due to the emergence of deadly and neurological adverse events, such as fatal brain edema in some patients included in early CAR T-cell trials, safety concerns for those with CNS primary or secondary infiltration arose and contributed to the routine exclusion of individuals with pre-existing or active CNS involvement from pivotal trials. However, based primarily on the lack of evidence, it remains unknown whether CNS involvement increases the risk and/or severity of CAR T-cell-related neurotoxicity. Given the limited treatment options available for patients once they relapse with CNS involvement, it is of high interest to explore the role of novel clinical strategies including CAR T cells to treat leukemias/lymphomas and myeloma with CNS involvement. The purpose of this review was to summarize currently available neurological safety data of CAR T-cell-based immunotherapy from the clinical trials and real-world experiences in adult patients with CNS disease due to lymphoma, leukemia, or myeloma. Increasing evidence supports that CNS involvement in hematologic disease should no longer be considered per se as an absolute contraindication to CAR T-cell-based therapy. While the incidence may be high, severity does not appear to be impacted significantly by pre-existing CNS status. Close monitoring by trained neurologists is recommended.

Neurological Complications of Conventional and Novel Anticancer Treatments

Various neurological complications, affecting both the central and peripheral nervous system, can frequently be experienced by cancer survivors after exposure to conventional chemotherapy, but also to modern immunotherapy. In this review, we provide an overview of the most well-known adverse events related to chemotherapy, with a focus on chemotherapy induced peripheral neurotoxicity, but we also address some emerging novel clinical entities related to cancer treatment, including chemotherapy-related cognitive impairment and immune-mediated adverse events. Unfortunately, efficacious curative or preventive treatment for all these neurological complications is still lacking. We provide a description of the possible mechanisms involved to drive future drug discovery in this field, both for symptomatic treatment and neuroprotection.