CAR T-Cell-Associated Neurotoxicity: Current Management and Emerging Treatment Strategies

Neuropsychological outcomes of patients with haematological malignancies undergoing chimeric antigen receptor T-cell therapy: protocol for a prospective study

Introduction

Immune effector cell-associated neurotoxicity syndrome (ICANS) is a common side-effect of chimeric antigen receptor T-cell (CAR-T) therapy, with symptoms ranging from mild to occasionally life-threatening. The neurological, cognitive, psychiatric and psychosocial sequelae of ICANS are diverse and not well defined, posing a challenge for diagnosis and management. The recovery trajectory of the syndrome is uncertain. Patients are rarely examined in this population pretherapy, adding a layer of complexity to specifying symptoms pertinent solely to CAR-T treatment. We present a protocol of a prospective longitudinal research study of adult patients in a single Australian haematology service undergoing CAR-T therapy. The study will describe neurocognitive features specific to ICANS, characterise the underlying syndrome, capture recovery, identify predictors of differential postinfusion outcomes and determine a set of cognitive instruments necessary to monitor patients acutely.

Methods and analysis

This is a prospective longitudinal study that comprises neuropsychological and neurological examinations occurring prior to CAR-T, during the acute post-treatment period, 28 days, 6 months and 12 months post infusion. Data will be sourced from objective psychometric measures, clinical examinations, self-report questionnaires of psychopathology and accounts of subjective cognitive complaint.

Ethics and dissemination

This study aims to guide diagnosis, management and monitoring of neurocognitive features of CAR-T cell therapy. Results of this study will be disseminated through publication in peer-reviewed journals and presentations at scientific conferences. All procedures involving human subjects/patients were approved by the Peter MacCallum Cancer Centre Human Research Ethics Committee (21/145).

Comparing the Differences in Adverse Events among Chimeric Antigen Receptor T-Cell Therapies: A Real-World Pharmacovigilance Study

In this study, we compared the similarities and differences in adverse events (AEs) among CAR T-cell products through signal mining via the FDA Adverse Event Reporting System (FAERS) and identified unknown AEs to provide a reference for safe clinical medication. Data from the FAERS database spanning from the fourth quarter of 2017 to the first quarter of 2024 were extracted. Signals were identified using the reporting odds ratio (ROR) method and the Medicines and Healthcare Products Regulatory Agency (MHRA) method. A total of 11,386 AE reports related to six CAR T-cell products were selected. The top three categories of AEs reported were nervous system disorders, immune system disorders, and general disorders and administration site conditions. However, there were variations in the AE spectra among the different CAR T-cell products. The BCMA-targeting drugs idecabtagene vicleucel (Ide-cel) and ciltacabtagene autoleucel (Cilta-cel) were found to be associated with parkinsonism, which were not observed in CD19-targeting drugs. Tisagenlecleucel (Tisa-cel) and axicabtagene ciloleucel (Axi-cel) exhibited cerebrovascular accident-related AEs, graft versus host disease, and abnormal coagulation indices. Cilta-cel was associated with cerebral hemorrhage, intracranial hemorrhage, cranial nerve disorder, and facial nerve disorder. Cardiopulmonary toxicity, including hypoxia, tachypnoea, cardiorenal syndrome, and hypotension, exhibited strong signal intensities and considerable overlap with CRS. The number of positive signals for cardiopulmonary toxicity associated with drugs targeting CD-19 is greater. Clinicians should assess patients prior to medication and closely monitor their vital signs, mental status, and laboratory parameters during treatment.

Toxicities of CAR T-cell therapy: a review of current literature

The chimeric antigen receptor (CAR) design, first invented by Zelig Eshhar, paved the way for the use of genetically modified T-cells in targeted therapy against cancer cells. Since then, it has gone through many generations, especially with the integration of co-stimulation in the second and third-generation CARs. However, it also mounts a hyperactive immune response named as cytokine release syndrome with the release of several cytokines eventually resulting in multiple end-organ toxicities. The severity of cytokine release syndrome depends upon certain factors such as the tumor burden, choice of co-stimulation, and degree of lymphodepletion, and can manifest as pulmonary edema, vascular leak, renal dysfunction, cardiac problems, hepatic failure, and coagulopathy. Many grading criteria have been used to define these clinical manifestations but they lack harmonization. Neurotoxicity has also been significantly associated with CAR T-cell therapy but it has not been studied much in previous literature. This review aims to provide a comprehensive account of the clinical manifestations, diagnosis, management, and treatment of CAR T-cell associated neurotoxicity.

Cellular and molecular imaging of CAR-T cell-based immunotherapy

Chimeric Antigen Receptor T cell (CAR-T) therapy has emerged as a transformative therapeutic strategy for hematological malignancies. However, its efficacy in treating solid tumors remains limited. An in-depth and comprehensive understanding of CAR-T cell signaling pathways and the ability to track CAR-T cell biodistribution and activation in real-time within the tumor microenvironment will be instrumental in designing the next generation of CAR-T cells for solid tumor therapy. This review summarizes the signaling network and the cellular and molecular imaging tools and platforms that are utilized in CAR-T cell-based immune therapies, covering both in vitro and in vivo studies. Firstly, we provide an overview of the existing understanding of the activation and cytotoxic mechanisms of CAR-T cells, compared to the mechanism of T cell receptor (TCR) signaling pathways. We further describe the commonly employed tools for live cell imaging, coupled with recent research progress, with a focus on genetically encoded fluorescent proteins (FPs) and biosensors. We then discuss the utility of diverse in vivo imaging modalities, including fluorescence and bioluminescence imaging, Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET), and photoacoustic (PA) imaging, for noninvasive monitoring of CAR-T cell dynamics within tumor tissues, thereby providing critical insights into therapy's strengths and weaknesses. Lastly, we discuss the current challenges and future directions of CAR-T cell therapy from the imaging perspective. We foresee that a comprehensive and integrative approach to CAR-T cell imaging will enable the development of more effective treatments for solid tumors in the future.

An updated overview of the application of CAR-T cell therapy in neurological diseases

Genetically modified immune cells, especially CAR-T cells, have captured the attention of scientists over the past 10 years. In the fight against cancer, these cells have a special place. Treatment for hematological cancers, autoimmune disorders, and cancers must include CAR-T cell therapy. Determining the therapeutic targets, side effects, and use of CAR-T cells in neurological disorders, including cancer and neurodegenerative diseases, is the goal of this study. Due to advancements in genetic engineering, CAR-T cells have become crucial in treating some neurological disorders. CAR-T cells have demonstrated a positive role in treating neurological cancers like Glioblastoma and Neuroblastoma due to their ability to cross the blood-brain barrier and use diverse targets. However, CAR-T cell therapy for MS diseases is being researched and could be a potential treatment option. This study aimed to access the most recent studies and scientific articles in the field of CAR-T cells in neurological diseases and/or disorders.

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

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

Cellular Senescence: From Mechanisms to Current Biomarkers and Senotherapies

An increase in life expectancy in developed countries has led to a surge of chronic aging-related diseases. In the last few decades, several studies have provided evidence of the prominent role of cellular senescence in many of these pathologies. Key traits of senescent cells include cell cycle arrest, apoptosis resistance, and secretome shift to senescence-associated secretory phenotype resulting in increased secretion of various intermediate bioactive factors important for senescence pathophysiology. However, cellular senescence is a highly phenotypically heterogeneous process, hindering the discovery of totally specific and accurate biomarkers. Also, strategies to prevent the pathologic effect of senescent cell accumulation during aging by impairing senescence onset or promoting senescent cell clearance have shown great potential during in vivo studies, and some are already in early stages of clinical translation. The adaptability of these senotherapeutic approaches to human application has been questioned due to the lack of proper senescence targeting and senescence involvement in important physiologic functions. In this review, we explore the heterogeneous phenotype of senescent cells and its influence on the expression of biomarkers currently used for senescence detection. We also discuss the current evidence regarding the efficacy, reliability, development stage, and potential for human applicability of the main existing senotherapeutic strategies. SIGNIFICANCE STATEMENT: This paper is an extensive review of what is currently known about the complex process of cellular senescence and explores its most defining features. The main body of the discussion focuses on how the multifeature fluctuation of the senescence phenotype and the physiological role of cellular senescence have both caused a limitation in the search for truly reliable senescence biomarkers and the progression in the development of senotherapies.

Neurological adverse effects of chimeric antigen receptor T-cell therapy

INTRODUCTION

Chimeric antigen receptor (CAR) T-cell is among the most prevalent approaches that act by directing T-cells toward cancer; however, they need to be optimized to minimize side effects and maximize efficacy before being used as standard treatment for malignancies. Neurotoxicity associated with CAR T-cell therapy has been well-documented in recent works.

AREAS COVERED

In this regard, two established syndromes exist. Immune effector cell-associated neurotoxicity syndrome (ICANS), previously called cytokine release encephalopathy syndrome (CRES), is a neuropsychiatric condition which can occur after therapy by immune effector cells (IEC) and T-lymphocytes utilizing treatments. Another syndrome is cytokine release syndrome (CRS), which may overlap with ICANS.

EXPERT OPINION

ICANS clinical manifestations include cerebral edema, mild lethargy, aphasia, and seizures. Notably, ICANS is associated with changes to EEG and neuroradiological findings. Therefore, it is necessary to make a timely and accurate diagnosis of neurological complications of CAR T-cells by clinical presentations, neuroimaging, and EEG. Since neurological events by different CAR T-cell products are heterogeneous, guides should be developed according to each product. Here, we provide an updated review of general information on CAR T-cell therapies and applications, neurological syndromes associated with their use, and risk factors contributing to ICANS.

Tumor microenvironment: barrier or opportunity towards effective cancer therapy

Tumor microenvironment (TME) is a specialized ecosystem of host components, designed by tumor cells for successful development and metastasis of tumor. With the advent of 3D culture and advanced bioinformatic methodologies, it is now possible to study TME’s individual components and their interplay at higher resolution. Deeper understanding of the immune cell’s diversity, stromal constituents, repertoire profiling, neoantigen prediction of TMEs has provided the opportunity to explore the spatial and temporal regulation of immune therapeutic interventions. The variation of TME composition among patients plays an important role in determining responders and non-responders towards cancer immunotherapy. Therefore, there could be a possibility of reprogramming of TME components to overcome the widely prevailing issue of immunotherapeutic resistance. The focus of the present review is to understand the complexity of TME and comprehending future perspective of its components as potential therapeutic targets. The later part of the review describes the sophisticated 3D models emerging as valuable means to study TME components and an extensive account of advanced bioinformatic tools to profile TME components and predict neoantigens. Overall, this review provides a comprehensive account of the current knowledge available to target TME.

Interleukin Inhibitors in Cytokine Release Syndrome and Neurotoxicity Secondary to CAR-T Therapy

INTRODUCTION

Chimeric antigen receptor T-cell (CAR-T) therapy is an innovative therapeutic option for addressing certain recurrent or refractory hematological malignancies. However, CAR-T cells also cause the release of pro-inflammatory cytokines that lead to life-threatening cytokine release syndrome and neurotoxicity.

OBJECTIVE

To study the efficacy of interleukin inhibitors in addressing cytokine release syndrome (CRS) and neurotoxicity secondary to CAR-T therapy.

METHODOLOGY

The authors conducted a bibliographic review in which 10 articles were analyzed. These included cut-off studies, case reports, and clinical trials involving 11 cancer centers and up to 475 patients over 18 years of age.

RESULTS

Tocilizumab is the only interleukin inhibitor approved to address CRS secondary to CAR-T therapy due to its efficacy and safety. Other inhibitors, such as siltuximab and anakinra, could be useful in combination with tocilizumab for preventing severe cytokine release and neurotoxicity. In addition, the new specific inhibitors could be effective in mitigating CRS without affecting the cytotoxic efficacy of CAR-T therapy.

CONCLUSION

More lines of research should be opened to elucidate the true implications of these drugs in treating the side effects of CAR-T therapy.

Application of blood brain barrier models in pre-clinical assessment of glioblastoma-targeting CAR-T based immunotherapies

Human blood brain barrier (BBB) models derived from induced pluripotent stem cells (iPSCs) have become an important tool for the discovery and preclinical evaluation of central nervous system (CNS) targeting cell and gene-based therapies. Chimeric antigen receptor (CAR)-T cell therapy is a revolutionary form of gene-modified cell-based immunotherapy with potential for targeting solid tumors, such as glioblastomas. Crossing the BBB is an important step in the systemic application of CAR-T therapy for the treatment of glioblastomas and other CNS malignancies. In addition, even CAR-T therapies targeting non-CNS antigens, such as the well-known CD19-CAR-T therapies, are known to trigger CNS side-effects including brain swelling due to BBB disruption. In this study, we used iPSC-derived brain endothelial-like cell (iBEC) transwell co-culture model to assess BBB extravasation of CAR-T based immunotherapies targeting U87MG human glioblastoma (GBM) cells overexpressing the tumor-specific mutated protein EGFRvIII (U87vIII). Two types of anti-EGFRvIII targeting CAR-T cells, with varying tonic signaling profiles (CAR-F263 and CAR-F269), and control Mock T cells were applied on the luminal side of BBB model in vitro. CAR-F263 and CAR-F269 T cells triggered a decrease in transendothelial electrical resistance (TEER) and an increase in BBB permeability. CAR-T cell extravasation and U87vIII cytotoxicity were assessed from the abluminal compartment using flow cytometry and Incucyte real-time viability imaging, respectively. A significant decrease in U87vIII cell viability was observed over 48 h, with the most robust cytotoxicity response observed for the constitutively activated CAR-F263. CAR-F269 T cells showed a similar cytotoxic profile but were approximately four fold less efficient at killing the U87vIII cells compared to CAR-F263, despite similar transmigration rates. Visualization of CAR-T cell extravasation across the BBB was further confirmed using BBTB-on-CHIP models. The described BBB assay was able to discriminate the cytotoxic efficacies of different EGFRvIII-CARs and provide a measure of potential alterations to BBB integrity. Collectively, we illustrate how BBB models in vitro can be a valuable tool in deciphering the mechanisms of CAR-T–induced BBB disruption, accompanying toxicity and effector function on post-barrier target cells.

[Optimization of CD19 chimeric antigen receptor T cell establishment and observation of the killing effect in vitro and in vivo]

Objective: To optimize the stimulation and activation system of mouse CD3(+) T cells in vitro and explore the optimal infection time of CD3(+) T cells to establish mouse CD19 chimeric antigen receptor T cells (mCD19 CAR-T) , and to also verify its killing effect in vivo and in vitro. Method: Splenic CD3(+)T cells were isolated and purified using magnetic beads, and the cells were cultured in Soluble anti-CD3/CD28, PMA+Ionomycin, and Plated anti-CD3/CD28. Cell activation and apoptosis were assessed by flow cytometry after 8, 24, 48, and 72 hours. ScFv plasmid of mouse CD19 antibody was transfected to plat-E cells to package retrovirus. Activated CD3(+) T cells were infected to construct mouse-specific CD19 chimeric antigen receptor T cells (mCD19 CAR-T) , and mCD19 CAR-T cells were co-cultured with B-cell lymphoma cell line A20 in vitro. The specific toxicity of A20 was detected by flow cytometry, and mCD19 CAR-T cells were infused into the lymphoma mouse model to detect its killing effect and distribution. Results: The activation effect of Plated anti-CD3/CD28 on CD3(+) T cells was superior, with the cells exhibiting good viability 24-48 hours after stimulation. Established mCD19 CAR-T cells with stable efficiency[ (32.27±7.56) % ] were specifically able to kill A20 tumor cells (The apoptosis rate was 24.3% at 48 h) . In vivo detection showed a non-significant decrease in the percentage[ (1.83±0.58) % ] of splenic CD19(+) cells 6 days after mCD19 CAR-T cell infusion. A marked clearance in bone marrow and spleen appeared on day 12 compared with the A20 group, and this difference was statistically significant[spleen: (0.36±0.04) % vs (47.00±13.46) % , P<0.001; bone marrow: (1.82±0.29) % vs (37.30±1.44) % , P<0.0001]. Moreover, mCD19 CAR-T cells were distributed in high proportions in the peripheral blood, spleen, and bone marrow[ (2.90±1.12) % , (4.96±0.80) % , (13.55±1.56) % ]. Conclusion: This study demonstrated an optimized activation system and the optimal infection time of CD3(+) T cells. Furthermore, stable constructed mCD19 CAR-T cells showed a remarkable killing ability in vitro and in vivo.

Neurotoxicity Associated with Treatment of Acute Lymphoblastic Leukemia Chemotherapy and Immunotherapy

Immunotherapy is a milestone in the treatment of poor-prognosis pediatric acute lymphoblastic leukemia (ALL) and is expected to improve treatment outcomes and reduce doses of conventional chemotherapy without compromising the effectiveness of the therapy. However, both chemotherapy and immunotherapy cause side effects, including neurological ones. Acute neurological complications occur in 3.6–11% of children treated for ALL. The most neurotoxical chemotherapeutics are L-asparaginase (L-ASP), methotrexate (MTX), vincristine (VCR), and nelarabine (Ara-G). Neurotoxicity associated with methotrexate (MTX-NT) occurs in 3–7% of children treated for ALL and is characterized by seizures, stroke-like symptoms, speech disturbances, and encephalopathy. Recent studies indicate that specific polymorphisms in genes related to neurogenesis may have a predisposition to MTX toxicity. One of the most common complications associated with CAR T-cell therapy is immune effector cell-associated neurotoxicity syndrome (ICANS). Mechanisms of neurotoxicity in CAR T-cell therapy are still unknown and may be due to disruption of the blood–brain barrier and the effects of elevated cytokine levels on the central nervous system (CNS). In this review, we present an analysis of the current knowledge on the mechanisms of neurotoxicity of standard chemotherapy and the targeted therapy in children with ALL.

Targeting CD10 on B-Cell Leukemia Using the Universal CAR T-Cell Platform (UniCAR)

Chimeric antigen receptor (CAR)-expressing T-cells are without a doubt a breakthrough therapy for hematological malignancies. Despite their success, clinical experience has revealed several challenges, which include relapse after targeting single antigens such as CD19 in the case of B-cell acute lymphoblastic leukemia (B-ALL), and the occurrence of side effects that could be severe in some cases. Therefore, it became clear that improved safety approaches, and targeting multiple antigens, should be considered to further improve CAR T-cell therapy for B-ALL. In this paper, we address both issues by investigating the use of CD10 as a therapeutic target for B-ALL with our switchable UniCAR system. The UniCAR platform is a modular platform that depends on the presence of two elements to function. These include UniCAR T-cells and the target modules (TMs), which cross-link the T-cells to their respective targets on tumor cells. The TMs function as keys that control the switchability of UniCAR T-cells. Here, we demonstrate that UniCAR T-cells, armed with anti-CD10 TM, can efficiently kill B-ALL cell lines, as well as patient-derived B-ALL blasts, thereby highlighting the exciting possibility for using CD10 as an emerging therapeutic target for B-cell malignancies.

IL-6/IFN-γ double knockdown CAR-T cells reduce the release of multiple cytokines from PBMCs in vitro

CD19-targeted chimeric antigen receptor T (anti-CD19 CAR-T) cells have shown good therapeutic results in the treatment of CD19 + B cell acute lymphocytic leukemia and lymphoma. However, severe side reactions and cytotoxicity are great challenges in the application of anti-CD19 CAR-T cell therapy. Cytokine release syndrome (CRS) is the main side effect of CAR-T cell treatment, and interleukin-6 (IL-6) and interferon γ (IFN-γ) are cytokines that play major roles in CRS. Therefore, we investigated double knockdown (KD) of IL-6 and IFN-γ as a potential strategy to manage anti-CD19 CAR-T cell-associated CRS. These improved anti-CD19 CAR-T cells therapy retained the advantages of the original anti-CD19 CAR-T cells and additionally reduced the release of cytokines from CAR-T cells and other immune cells. Moreover, this study presented a novel approach to abrogate CRS through IL-6 and IFN-γ KD, which may potentially inhibit the release of multiple cytokines from CAR-T cells and peripheral blood mononuclear cells (PBMCs), a model of CRS correlate with in vivo features of the CAR-T therapy, thereby reducing the impact of CRS, improving the safety of CAR-T cell treatment, reducing toxicities, and maintaining the function of CAR-T cells.

Chimeric Antigen Receptor T-Cell Therapy in Lung Cancer: Potential and Challenges

Chimeric antigen receptor T (CAR-T) cell therapy has exhibited a substantial clinical response in hematological malignancies, including B-cell leukemia, lymphoma, and multiple myeloma. Therefore, the feasibility of using CAR-T cells to treat solid tumors is actively evaluated. Currently, multiple basic research projects and clinical trials are being conducted to treat lung cancer with CAR-T cell therapy. Although numerous advances in CAR-T cell therapy have been made in hematological tumors, the technology still entails considerable challenges in treating lung cancer, such as on−target, of−tumor toxicity, paucity of tumor-specific antigen targets, T cell exhaustion in the tumor microenvironment, and low infiltration level of immune cells into solid tumor niches, which are even more complicated than their application in hematological tumors. Thus, progress in the scientific understanding of tumor immunology and improvements in the manufacture of cell products are advancing the clinical translation of these important cellular immunotherapies. This review focused on the latest research progress of CAR-T cell therapy in lung cancer treatment and for the first time, demonstrated the underlying challenges and future engineering strategies for the clinical application of CAR-T cell therapy against lung cancer.

From antibodies to living drugs: Quo vadis cancer immunotherapy?

In the last few decades, monoclonal antibodies targeting various receptors and ligands have shown significant advance in cancer therapy. However, still a great percentage of patients experiences tumor relapse despite persistent antigen expression. Immune cell therapy with adoptively transferred modified T cells that express chimeric antigen receptors (CAR) is an engaging option to improve disease outcome. Designer T cells have been applied with remarkable success in the treatment for acute B cell leukemias, yielding unprecedented antitumor activity and significantly improved overall survival. Relying on the success of CAR T cells in leukemias, solid tumors are now emerging potential targets; however, their complexity represents a significant challenge. In preclinical models, CAR T cells recognized and efficiently killed the wide spectrum of tumor xenografts; however, in human clinical trials, limited antitumor efficacy and serious side effects, including cytokine release syndrome, have emerged as potential limitations. The next decade will be an exciting time to further optimize this novel cellular therapeutics to improve effector functions and, at the same time, keep adverse events in check. Moreover, we need to establish whether gene-modified T cells which are yet exclusively used for cancer patients could also be successful in the treatment for other diseases. Here, we provide a concise overview about the transition from monoclonal antibodies to the generation of chimeric antigen receptor T cells. We summarize lessons learned from preclinical models, including our own HER2-positive tumor models, as well as from clinical trials worldwide. We also discuss the challenges we are facing today and outline future prospects.

CAR T-Cell Therapy: An Update for Radiologists

Chimeric antigen receptor-engineer (CAR) T-cell therapy is a promising novel immunotherapy that has the potential to revolutionize cancer treatment. With four CAR T-cell therapies receiving FDA approval within the last 5 years, the role of CAR T-cells is anticipated to continue to evolve and expand. However, various aspects of CAR T-cell therapies remain poorly understood, and the therapies are associated with severe side effects [including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity (ICANS)] that require prompt diagnosis and intervention. In this review, we discuss the role of imaging in diagnosing and monitoring toxicities from CAR T-cell therapies and explore the application of various imaging techniques, including use of PET/CT with novel radiotracers, to predict and assess treatment response and adverse effects. It is important for radiologists to recognize the imaging findings associated with each syndrome, as well as the typical and atypical treatment response patterns associated with CAR T-cell therapy. Given the expected increase in use of CAR T-cells in the near future, radiologists should familiarize themselves with the imaging findings encountered in these novel therapies, to provide comprehensive and up-to-date guidance for clinical management.

CAR-T Cell Therapy: Mechanism, Management, and Mitigation of Inflammatory Toxicities

Engineered T cell therapies such as chimeric antigen receptor (CAR) expressing T cells (CAR-T cells) have great potential to treat many human diseases; however, inflammatory toxicities associated with these therapies present safety risks and can greatly limit its widespread use. This article briefly reviews our current understanding of mechanisms for inflammatory toxicities during CAR T-cell therapy, current strategies for management and mitigation of these risks and highlights key areas of knowledge gap for future research.

Immune Effector Cell Associated Neurotoxicity (ICANS) in Pediatric and Young Adult Patients Following Chimeric Antigen Receptor (CAR) T-Cell Therapy: Can We Optimize Early Diagnosis?

The Cornell Assessment for Pediatric Delirium (CAPD) was first proposed by the Pediatric Acute Lung Injury and Sepsis Investigators Network-Stem Cell Transplantation and Cancer Immunotherapy Subgroup and MD Anderson CARTOX joint working committees, for detection of immune effector cell associated neurotoxicity (ICANS) in pediatric patients receiving chimeric antigen receptor (CAR) T-cell therapy. It was subsequently adopted by the American Society for Transplantation and Cellular Therapy. The utility of CAPD as a screening tool for early diagnosis of ICANS has not been fully characterized. We conducted a retrospective study of pediatric and young adult patients (n=15) receiving standard-of-care CAR T-cell products. Cytokine release syndrome (CRS) and ICANS occurred in 87% and 40% of patients, respectively. ICANS was associated with significantly higher peaks of serum ferritin. A change in CAPD from a prior baseline was noted in 60% of patients with ICANS, 24–72 h prior to diagnosis of ICANS. The median change from baseline to maximum CAPD score of patients who developed ICANS versus those who did not was 13 versus 3, respectively (p=0.0004). Changes in CAPD score from baseline may be the earliest indicator of ICANS among pediatric and young adult patients which may warrant closer monitoring, with more frequent CAPD assessments.

Safety and Efficacy of Chimeric Antigen Receptor T-Cell Therapy in Children With Central Nervous System Leukemia

BACKGROUND

chimeric antigen receptor-modified T cell (CAR-T) therapy is an effective and promising treatment for refractory and multiply relapsed B-cell acute lymphoblastic leukemia (B-ALL). Because of its side effects and poor responses such as neurotoxicity and cytokine release syndrome, patients with central nervous system leukemia were excluded in most previous clinical trials of CAR-T treatment.

PATIENTS AND METHODS

We enrolled 3 B-ALL patients with central nervous system leukemia relapse. They were infused with CD19-specific CAR-Ts, and their clinical responses were evaluated by bone marrow smear, flow cytometry, and cytogenetic alterations detected by quantitative PCR, interleukin-6, and the expansion and persistence of circulating CAR-Ts in peripheral blood and cerebrospinal fluid.

RESULTS

After CAR-T infusion, 2 of the 3 patients experienced bone marrow minimal residual disease-negative complete remission, and all patients tested negative for residual leukemia cells in cerebrospinal fluid tested by flow cytometry. These 3 patients experienced grade 2 or 3 cytokine release syndrome, which resolved completely after symptomatic treatment. None experienced neurotoxicity or needed further intensive care.

CONCLUSION

CAR-T infusion is a potentially effective treatment for relapsed/refractory B-ALL patients with central nervous system involvement.

Cytokines in CAR T Cell-Associated Neurotoxicity

Chimeric antigen receptor (CAR) T cells provide new therapeutic options for patients with relapsed/refractory hematologic malignancies. However, neurotoxicity is a frequent, and potentially fatal, complication. The spectrum of manifestations ranges from delirium and language dysfunction to seizures, coma, and fatal cerebral edema. This novel syndrome has been designated immune effector cell-associated neurotoxicity syndrome (ICANS). In this review, we draw an arc from our current understanding of how systemic and potentially local cytokine release act on the CNS, toward possible preventive and therapeutic approaches. We systematically review reported correlations of secreted inflammatory mediators in the serum/plasma and cerebrospinal fluid with the risk of ICANS in patients receiving CAR T cell therapy. Possible pathophysiologic impacts on the CNS are covered in detail for the most promising candidate cytokines, including IL-1, IL-6, IL-15, and GM-CSF. To provide insight into possible final common pathways of CNS inflammation, we place ICANS into the context of other systemic inflammatory conditions that are associated with neurologic dysfunction, including sepsis-associated encephalopathy, cerebral malaria, thrombotic microangiopathy, CNS infections, and hepatic encephalopathy. We then review in detail what is known about systemic cytokine interaction with components of the neurovascular unit, including endothelial cells, pericytes, and astrocytes, and how microglia and neurons respond to systemic inflammatory challenges. Current therapeutic approaches, including corticosteroids and blockade of IL-1 and IL-6 signaling, are reviewed in the context of what is known about the role of cytokines in ICANS. Throughout, we point out gaps in knowledge and possible new approaches for the investigation of the mechanism, prevention, and treatment of ICANS.

C-reactive protein and ferritin levels and length of intensive care unit stay in patients with B-cell lymphomas treated with axicabtagene ciloleucel

OBJECTIVE/BACKGROUND

Chimeric antigen receptor (CAR) T-cell is an effective therapy in relapsed/refractory large B-cell lymphomas that, due to its unique toxicities, often requires escalation of care to the intensive care unit (ICU) setting. C-reactive protein (CRP) and ferritin are serum inflammatory markers associated with onset and persistence of CAR T-cell-related toxicity.

METHODS

We retrospectively analyzed 34 patients treated with axicabtagene ciloleucel (axi-cel) who were divided into two groups: patients requiring admission to the ICU during initial hospitalization (n = 13, 38%) and those who did not (n = 21, 62%). Primary objective was to examine possible relationships between serum ferritin and/or CRP levels with the need for, and length of, ICU stay between these groups.

RESULTS

All 13 patients admitted to the ICU developed cytokine release syndrome (CRS) and 11 of them also developed neurotoxicity (NT). Of the 21 patients in the non-ICU group, 18 developed CRS and 5 patients developed NT. Grade of CRS and NT were higher in ICU versus non-ICU patients (p = .03 and .001, respectively). There was no correlation between CRP levels at time of ICU admission and length of ICU stay (correlation of 0.41, p = .17). Yet, there was an association between serum ferritin levels and length of ICU stay (R² = 0.73) which did not reach statistical significance (correlation of 0.21, p = .49).

CONCLUSION

Notwithstanding the limitations of the small sample size, our study suggests that an elevated ferritin level at the time of escalation of medical care may be possibly indicative of anticipated prolonged ICU hospitalization in patients treated with axi-cel. A large multicenter study is certainly needed to confirm this observation.

[Chimeric antigen receptors in oncology: clinical applications and new developments]

In 2018, two novel cancer therapies based on chimeric antigen receptors (CARs) were granted marketing authorization in the European Union. Authorized for use against advanced lymphoma and/or leukemia, the products were at the center of international attention, not only due to their novel mode of action and their encouraging efficacy but also because of their sometimes severe side effects and the economic and logistic challenges posed by their manufacture. Now, almost two years later, hundreds of active clinical trials emphasize the global drive to harness the full potential of CAR technology.In this article, we describe the mode of action of CAR T and CAR NK cells and review the clinical testing situation as well as early real-world data. In recent years, preclinical studies using advanced animal models have provided first insights into the mechanisms underlying the severe side effects of CAR T therapy. We summarize their results and describe the available models. Additionally, we discuss potential solutions to the hurdles currently limiting CAR technology. So far used as last-line treatment for patients with aggressive disease, CAR technology has the potential to become a new, broadly effective standard for tumor therapy.