Neurotoxicity Associated with CD19-Targeted CAR-T Cell Therapies

The use of ICU resources in CAR-T cell recipients: a hospital-wide study

Background

CAR-T cell (chimeric antigen receptor T) therapy has emerged as an effective treatment of refractory hematological malignancies. Intensive care management is intrinsic to CAR-T cell therapy. We aim to describe and to assess outcomes in critically ill CAR-T cell recipients.

Study design and methods

Hospital-wide retrospective study. Consecutive CAR-T cell recipients requiring ICU admission from July 2017 and December 2020 were included.

Results

71 patients (median age 60 years [37–68]) were admitted to the ICU 6 days [4–7] after CAR-T cell infusion. Underlying malignancies included diffuse large B cell lymphoma (n = 53, 75%), acute lymphoblastic leukemia (17 patients, 24%) and multiple myeloma (n = 1, 1.45%). Performance status (PS) was 1 [1–2]. Shock was the main reason for ICU admission (n = 40, 48%). Isolated cytokine release syndrome (CRS) was the most common complication (n = 33, 46%), while 21 patients (30%) had microbiologically documented bacterial infection (chiefly catheter-related infection). Immune effector cell-associated neurotoxicity syndrome was reported in 26 (37%) patients. At ICU admission, vasopressors were required in 18 patients (25%) and invasive mechanical ventilation in two. Overall, 49 (69%) and 40 patients (56%) received tocilizumab or steroids, respectively.

Determinant of mortality were the reason for ICU admission (disease progression vs. sepsis or CRS (HR 4.02 [95%CI 1.10–14.65]), Performance status (HR 1.97/point [95%CI 1.14–3.41]) and SOFA score (HR 1.16/point [95%CI 1.01–1.33]).

Conclusions

Meaningful survival could be achieved in up to half the CAR-T cell recipients. The severity of organ dysfunction is a major determinant of death, especially in patients with altered performance status or disease progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01036-2.

B cell-targeted therapies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that primarily affects women of childbearing age. There is no disease more heterogeneous than SLE as patients experience a myriad of manifestations and unpredictable periods of heightened disease activity. This heterogeneity not only makes it difficult for treatment decisions and prognostication, but has made drug development quite challenging. Despite these challenges, belimumab, voclosporin, and anifromulab, approved by the United States Food and Drug Administration (FDA) to treat SLE or lupus nephritis (LN), enhanced our armamentarium of traditional therapies, such as hydroxychloroquine, corticosteroids, and immunosuppressives. However, there remains a dire need to develop therapies that offer greater efficacy and safety. Patients with SLE produce excessive amounts of autoantibodies and cytokines that result in inflammation and organ damage. While a considerable number of potential drug development targets exist, there has been much attention focused on B cells. Strategies have included direct B cell killing, modulation of B cell function, inhibition of molecules essential to B cell growth and survival, and acceleration of autoantibody clearance, to name just a few. In this article, we review SLE clinical trials evaluating experimental agents that target B cells or plasma cells.

The landscape of chimeric antigen receptor T cell therapy in breast cancer: Perspectives and outlook

Chimeric antigen receptor-T (CAR-T) cell therapy is a revolutionary adoptive cell therapy, which could modify and redirect T cells to specific tumor cells. Since CAR-T cell therapy was first approved for B cell-derived malignancies in 2017, it has yielded unprecedented progress in hematological tumors and has dramatically reshaped the landscape of cancer therapy in recent years. Currently, cumulative evidence has demonstrated that CAR-T cell therapy could be a viable therapeutic strategy for solid cancers. However, owing to the immunosuppressive tumor microenvironment (TME) and heterogenous tumor antigens, the application of CAR-T cell therapy against solid cancers requires circumventing more challenging obstacles. Breast cancer is characterized by a high degree of invasiveness, malignancy, and poor prognosis. The review highlights the underlying targets of CAR-T cell therapy in breast cancer, summarizes the challenges associated with CAR-T cell therapy, and proposes the strategies to overcome these challenges, which provides a novel approach to breast cancer treatment.

Chimeric Antigen Receptor (CAR)-T Cell Immunotherapy Against Thoracic Malignancies: Challenges and Opportunities

Different from surgery, chemical therapy, radio-therapy and target therapy, Chimeric antigen receptor-modified T (CAR-T) cells, a novel adoptive immunotherapy strategy, have been used successfully against both hematological tumors and solid tumors. Although several problems have reduced engineered CAR-T cell therapeutic outcomes in clinical trials for the treatment of thoracic malignancies, including the lack of specific antigens, an immunosuppressive tumor microenvironment, a low level of CAR-T cell infiltration into tumor tissues, off-target toxicity, and other safety issues, CAR-T cell treatment is still full of bright future. In this review, we outline the basic structure and characteristics of CAR-T cells among different period, summarize the common tumor-associated antigens in clinical trials of CAR-T cell therapy for thoracic malignancies, and point out the current challenges and new strategies, aiming to provide new ideas and approaches for preclinical experiments and clinical trials of CAR-T cell therapy for thoracic malignancies.

CAR-T Cell Therapy in Hematological Malignancies: Current Opportunities and Challenges

Chimeric antigen receptor T (CAR-T) cell therapy represents a major breakthrough in cancer treatment, and it has achieved unprecedented success in hematological malignancies, especially in relapsed/refractory (R/R) B cell malignancies. At present, CD19 and BCMA are the most common targets in CAR-T cell therapy, and numerous novel therapeutic targets are being explored. However, the adverse events related to CAR-T cell therapy might be serious or even life-threatening, such as cytokine release syndrome (CRS), CAR-T-cell-related encephalopathy syndrome (CRES), infections, cytopenia, and CRS-related coagulopathy. In addition, due to antigen escape, the limited CAR-T cell persistence, and immunosuppressive tumor microenvironment, a considerable proportion of patients relapse after CAR-T cell therapy. Thus, in this review, we focus on the progress and challenges of CAR-T cell therapy in hematological malignancies, such as attractive therapeutic targets, CAR-T related toxicities, and resistance to CAR-T cell therapy, and provide some practical recommendations.

Emerging Management Approach for the Adverse Events of Immunotherapy of Cancer

Immunotherapy, which stimulates the body’s immune system, has received a considerable amount of press in recent years because of its powerful benefits. Cancer immunotherapy has shown long-term results in patients with advanced disease that are not seen with traditional chemotherapy. Immune checkpoint inhibitors, cytokines like interleukin 2 (IL-2) and interferon-alpha (IFN), and the cancer vaccine sipuleucel-T have all been licensed and approved by the FDA for the treatment of various cancers. These immunotherapy treatments boost anticancer responses by stimulating the immune system. As a result, they have the potential to cause serious, even fatal, inflammatory and immune-related side effects in one or more organs. Immune checkpoint inhibitors (ICPIs) and chimeric antigen receptor (CAR) T-cell therapy are two immunotherapy treatments that are increasingly being used to treat cancer. Following their widespread usage in the clinic, a wave of immune-related adverse events (irAEs) impacting virtually every system has raised concerns about their unpredictability and randomness. Despite the fact that the majority of adverse effects are minimal and should be addressed with prudence, the risk of life-threatening complications exists. Although most adverse events are small and should be treated with caution, the risk of life-threatening toxicities should not be underestimated, especially given the subtle and unusual indications that make early detection even more difficult. Treatment for these issues is difficult and necessitates a multidisciplinary approach involving not only oncologists but also other internal medicine doctors to guarantee quick diagnosis and treatment. This study’s purpose is to give a fundamental overview of immunotherapy and cancer-related side effect management strategies.

Efficacy and safety of CD19-specific CAR T cell-based therapy in B-cell acute lymphoblastic leukemia patients with CNSL

Few studies have described chimeric antigen receptor (CAR) T-cell therapy for patients with B-cell acute lymphoblastic leukemia (B-ALL) with central nervous system leukemia (CNSL) because of concerns regarding poor response and treatment-related neurotoxicity. Our study included 48 patients with relapsed/refractory B-ALL with CNSL to evaluate the efficacy and safety of CD19-specific CAR T cell-based therapy. The infusion resulted in an overall response rate of 87.5% (95% confidence interval [CI], 75.3-94.1) in bone marrow (BM) disease and remission rate of 85.4% (95% CI, 72.8-92.8) in CNSL. With a median follow-up of 11.5 months (range, 1.3-33.3), the median event-free survival was 8.7 months (95% CI, 3.7-18.8), and the median overall survival was 16.0 months (95% CI, 13.5-20.1). The cumulative incidences of relapse in BM and CNS diseases were 31.1% and 11.3%, respectively, at 12 months (P = .040). The treatment was generally well tolerated, with 9 patients (18.8%) experiencing grade ≥3 cytokine release syndrome. Grade 3 to 4 neurotoxic events, which developed in 11 patients (22.9%), were associated with a higher preinfusion disease burden in CNS and were effectively controlled under intensive management. Our results suggest that CD19-specific CAR T cell-based therapy can induce similar high response rates in both BM and CNS diseases. The duration of remission in CNSL was longer than that in BM disease. CD19 CAR T-cell therapy may provide a potential treatment option for previously excluded patients with CNSL, with manageable neurotoxicity. The clinical trials were registered at www.clinicaltrials.gov as #NCT02782351 and www.chictr.org.cn as #ChiCTR-OPN-16008526.

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.

Axicabtagene Ciloleucel in Patients Ineligible for ZUMA-1 Because of CNS Involvement and/or HIV: A Multicenter Experience

Secondary central nervous system lymphoma (SCNSL) is associated with poor prognosis and new therapeutic approaches are needed. The pivotal trial that led to US Food and Drug Administration (FDA) approval of axicabtagene ciloleucel excluded patients with SCNSL and human immunodeficiency virus. In this multi-institutional retrospective study, 14 SCNSL patients treated with axicabtagene ciloleucel, 3 of whom had human immunodeficiency virus, experienced rates of severe neurotoxicity and complete response of 32% and 58%, respectively. This is similar to rates observed in the pivotal ZUMA-1 trial that led to the approval of axi-cel at median follow-up of 5.9 months. Chimeric antigen receptor T-cell therapy is potentially a life-saving therapy for SCNSL patients and should not be withheld.

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.

Time to evolve: predicting engineered T cell-associated toxicity with next-generation models

Despite promising clinical results in a small subset of malignancies, therapies based on engineered chimeric antigen receptor and T-cell receptor T cells are associated with serious adverse events, including cytokine release syndrome and neurotoxicity. These toxicities are sometimes so severe that they significantly hinder the implementation of this therapeutic strategy. For a long time, existing preclinical models failed to predict severe toxicities seen in human clinical trials after engineered T-cell infusion. However, in recent years, there has been a concerted effort to develop models, including humanized mouse models, which can better recapitulate toxicities observed in patients. The Accelerating Development and Improving Access to CAR and TCR-engineered T cell therapy (T2EVOLVE) consortium is a public–private partnership directed at accelerating the preclinical development and increasing access to engineered T-cell therapy for patients with cancer. A key ambition in T2EVOLVE is to design new models and tools with higher predictive value for clinical safety and efficacy, in order to improve and accelerate the selection of lead T-cell products for clinical translation. Herein, we review existing preclinical models that are used to test the safety of engineered T cells. We will also highlight limitations of these models and propose potential measures to improve them.

Immune-Related Adverse Events (irAEs) in Cancer, with Inputs from a Nursing Expert: A Review

Immune checkpoint inhibitors (ICPis) belong to a group of immunotherapeutic agents that act on different immune cells and tumor cells and reactivate the suppressed immune system of the host. The emergence of immunotherapy has resulted in the successful management of many malignancies. High success rates with certain advanced cancers have attributed wide importance and relevance to the use of immunotherapy. Although ICPis have gained huge popularity, their use often leads to side effects that can affect almost any system; immune-related adverse events (irAEs). These adverse events occur due to unrestrained T cell activity that unsettles the immune homeostasis of the host. Although close monitoring for toxicities controls the events on most of the occasions, the inability to diagnose them early may prove fatal on some occasions due to their subtle and nonspecific symptoms. This review summarizes in brief the usual irAEs and their management, besides a very important nursing perspective, from a nursing expert about an overall insight into the routine irAEs.

Updates in the Management of Relapsed and Refractory Acute Lymphoblastic Leukemia: An Urgent Plea for New Treatments Is Being Answered!

The treatment of acute lymphoblastic leukemia (ALL) has dramatically changed over the past three decades. However, relapsed and/or refractory ALL still remains with a very low survival and high morbidity associated with its treatment. Here, we will review the outstanding progress that has been made in the treatment of relapsed and/or refractory ALL and discuss future directions and challenges that require further investigation.

Immune effector cell-associated neurotoxicity syndrome: A therapeutic approach in the critically ill

Immunotherapy with chimeric antigen-specific receptor modified T cells, known as CAR-T, is emerging as a promising approach to hematological malignancies. In this regard, CAR-T against human cluster of differentiation (CD) 19 has demonstrated antitumor efficacy in application to B cell neoplasms resistant to conventional therapy. However, activation of the immune system induces severe and specific complications which can prove life-threatening. These include cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome (known as ICANS) - the latter being the subject of the present review. Although the physiopathological mechanisms underlying ICANS are not well known, a number of clinical and biological factors increase the risk of developing neurotoxicity associated to CAR-T therapy. Treatment is based on close monitoring, measures of support, anticonvulsivants, corticosteroids, and early admission to intensive care. The present study offers a comprehensive review of the available literature from a multidisciplinary perspective, including recommendations from intensivists, neurologists and hematologists dedicated to the care of critically ill adults.

Antigen-Specific TCR-T Cells for Acute Myeloid Leukemia: State of the Art and Challenges

The cytogenetic abnormalities and molecular mutations involved in acute myeloid leukemia (AML) lead to unique treatment challenges. Although adoptive T-cell therapies (ACT) such as chimeric antigen receptor (CAR) T-cell therapy have shown promising results in the treatment of leukemias, especially B-cell malignancies, the optimal target surface antigen has yet to be discovered for AML. Alternatively, T-cell receptor (TCR)-redirected T cells can target intracellular antigens presented by HLA molecules, allowing the exploration of a broader territory of new therapeutic targets. Immunotherapy using adoptive transfer of WT1 antigen-specific TCR-T cells, for example, has had positive clinical successes in patients with AML. Nevertheless, AML can escape from immune system elimination by producing immunosuppressive factors or releasing several cytokines. This review presents recent advances of antigen-specific TCR-T cells in treating AML and discusses their challenges and future directions in clinical applications.

Validation of CD98hc as a Therapeutic Target for a Combination of Radiation and Immunotherapies in Head and Neck Squamous Cell Carcinoma

Most patients with head and neck squamous cell carcinomas (HNSCC) are diagnosed at a locally advanced stage and show heterogeneous treatment responses. Low SLC3A2 (solute carrier family 3 member 2) mRNA and protein (CD98hc) expression levels are associated with higher locoregional control in HNSCC patients treated with primary radiochemotherapy or postoperative radiochemotherapy, suggesting that CD98hc could be a target for HNSCC radiosensitization. One of the targeted strategies for tumor radiosensitization is precision immunotherapy, e.g., the use of chimeric antigen receptor (CAR) T cells. This study aimed to define the potential clinical value of new treatment approaches combining conventional radiotherapy with CD98hc-targeted immunotherapy. To address this question, we analyzed the antitumor activity of the combination of fractionated irradiation and switchable universal CAR (UniCAR) system against radioresistant HNSCC cells in 3D culture. CD98hc-redirected UniCAR T cells showed the ability to destroy radioresistant HNSCC spheroids. Also, the infiltration rate of the UniCAR T cells was enhanced in the presence of the CD98hc target module. Furthermore, sequential treatment with fractionated irradiation followed by CD98hc-redirected UniCAR T treatment showed a synergistic effect. Taken together, our obtained data underline the improved antitumor effect of the combination of radiotherapy with CD98hc-targeted immunotherapy. Such a combination presents an attractive approach for the treatment of high-risk HNSCC patients.

CAR-T cell therapy for lung cancer: Potential and perspective

Lung cancer is the highest incidence and mortality of all cancers around the world. In the present immunotherapy era, an increasing number of immunotherapeutic agents including monoclonal antibody‐targeted drugs have been used in the clinical treatment of malignancy, but it still has many limitations. Chimeric antigen receptor‐modified T (CAR‐T) cells, a novel adoptive immunotherapy strategy, have not only been used successfully against hematological tumors, but have also opened up new avenues for immunotherapy of solid tumors, including lung cancer. However, targeting lung cancer‐specific antigens using engineered CAR‐T cells is complicated by the lack of proper tumor‐specific antigens, an immunosuppressive tumor microenvironment, a low level of CAR‐T cell infiltration into tumor tissues, along with off‐target effect, etc. Simultaneously, the clinical application of CAR‐T cells remains limited because of many challenges such as tumor lysis syndrome, neurotoxicity syndrome, and cytokine release syndrome. In this review, we outline the basic structure and generation characteristic of CAR‐T cells and summarize the common tumor‐associated antigens in clinical trials of CAR‐T cell therapy for lung cancer, and point out the current challenges and new strategies, aiming to provide new ideas and approaches for the pre‐clinical experiments and clinical trials of CAR‐T cell therapy in lung cancer.

Immunotherapy Associated Neurotoxicity in Pediatric Oncology

Novel immunotherapies are increasingly being employed in pediatric oncology, both in the upfront and relapsed/refractory settings. Through various mechanisms of action, engagement and activation of the immune system can cause both generalized and disease site-specific inflammation, leading to immune-related adverse events (irAEs). One of the most worrisome irAEs is that of neurotoxicity. This can present as a large spectrum of neurological toxicities, including confusion, aphasia, neuropathies, seizures, and/or death, with variable onset and severity. Earlier identification and treatment, generally with corticosteroids, remains the mainstay of neurotoxicity management to optimize patient outcomes. The pathophysiology of neurotoxicity varies across the different therapeutic strategies and remains to be elucidated in most cases. Furthermore, little is known about long-term neurologic sequelae. This review will focus on neurotoxicity seen with the most common immunotherapies used in pediatric oncology, including CAR T cell therapy, alternative forms of adoptive cell therapy, antibody therapies, immune checkpoint inhibitors, and tumor vaccines. Herein we will discuss the incidence, pathophysiology, symptomatology, diagnosis, and management strategies currently being utilized for immunotherapy-associated neurotoxicity with a focus on pediatric specific considerations.

Natural Killer Cell-Mediated Immunotherapy for Leukemia

Simple Summary

Conventional therapies such as chemotherapy and radiation in leukemia increase infection susceptibility, adverse side effects and immune cell inactivation. Natural killer (NK) cells are the first line of defense against cancer and are critical in the recognition and cytolysis of rapidly dividing and abnormal cell populations. In this review, we describe NK cells and NK cell receptors, functional impairment of NK cells in leukemia, NK cell immunotherapies currently under investigation including monoclonal antibodies (mAbs), adoptive transfer, chimeric antigen receptor-NKs (CAR-NKs), bi-specific/tri-specific killer engagers (BiKEs/TriKEs) and potential targets of NK cell-mediated immunotherapy for leukemia in the future.

Abstract

Leukemia is a malignancy of the bone marrow and blood resulting from the abnormal differentiation of hematopoietic stem cells (HSCs). There are four main types of leukemia including acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myeloid leukemia (CML), and chronic lymphocytic leukemia (CLL). While chemotherapy and radiation have been conventional forms of treatment for leukemia, these therapies increase infection susceptibility, adverse side effects and immune cell inactivation. Immunotherapies are becoming promising treatment options for leukemia, with natural killer (NK) cell-mediated therapy providing a specific direction of interest. The role of NK cells is critical for cancer cell elimination as these immune cells are the first line of defense against cancer proliferation and are involved in both recognition and cytolysis of rapidly dividing and abnormal cell populations. NK cells possess various activating and inhibitory receptors, which regulate NK cell function, signaling either inhibition and continued surveillance, or activation and subsequent cytotoxic activity. In this review, we describe NK cells and NK cell receptors, functional impairment of NK cells in leukemia, NK cell immunotherapies currently under investigation, including monoclonal antibodies (mAbs), adoptive transfer, chimeric antigen receptor-NKs (CAR-NKs), bi-specific/tri-specific killer engagers (BiKEs/TriKEs) and future potential targets of NK cell-based immunotherapy for leukemia.

Use of Transcranial Doppler as a Biomarker of CAR T Cell-Related Neurotoxicity

Background and Objectives

To examine the relationship between transcranial Doppler (TCD) mean flow velocity (MFV) and the severity and temporal onset of neurotoxicity after chimeric antigen receptor (CAR) T-cell therapy in patients with relapsed lymphoma.

Methods

We identified a cohort of 165 patients with relapsed or refractory B-cell lymphoma who received CAR T-cell therapy. TCDs were performed at baseline, treatment day 5, and throughout hospitalization based on development of neurologic symptoms. We assessed the percent change in velocity from baseline in each of the 6 major supratentorial arteries and the relationship of these values to development and timing of neurotoxicity.

Results

Our cohort was 30% female with an average age of 60 years. Of patients with TCDs performed, 63% developed neurotoxicity, and 32% had severe neurotoxicity. The median time of neurotoxicity onset was day 7. Higher maximum percent change in MFV across all vessels was significantly associated with likelihood of developing neurotoxicity (p = 0.0002) and associated with severe neurotoxicity (p = 0.0421). We found that with increased percent change in MFV, the strength of correlation between day of TCD velocity change and day of neurotoxicity onset increased. There was no single vessel in which increase in MFV was associated with neurotoxicity.

Discussion

Our study demonstrates an association between increase in TCD MFV and the development of neurotoxicity, as well as timing of neurotoxicity onset. We believe that TCD ultrasound may be used as a bedside functional biomarker in CAR T-cell patients and may guide immunologic interventions to manage toxicity in this complex patient group.

Effect of early granulocyte-colony-stimulating factor administration in the prevention of febrile neutropenia and impact on toxicity and efficacy of anti-CD19 CAR-T in patients with relapsed/refractory B-cell lymphoma

Chimeric Antigen Receptor T cells (CAR-T) are an outbreaking treatment option for relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are the most common specific toxicities, while severe neutropenia and infections are often observed as well. From March 2020, early G-CSF prophylaxis at day (D) two post-infusion was systematically proposed. We then compared patients treated before that date who did not receive G-CSF or who received late (after D5) G-CSF as control group. Patients administered with early G-CSF had similar duration of grade 4 neutropenia but significantly decreased incidence of febrile neutropenia (58% versus 81%, p = 0.018). Similar rate of toxicities was observed, including overall and grade 3-4 CRS (p = 0.93 and p = 0.28, respectively), and overall and grade 3-4 ICANS (p = 0.62 and p = 0.88, respectively). We observed no difference in the quality of CAR T-cells expansion (p = 0.79, %Cmax), nor in response rate (best ORR, 57.6% vs 61.8%, p = 0.93), nor survival even in a group of patients adjusted by a propensity score. In conclusion, early G-CSF administration was safe and effective in reducing febrile neutropenia without impact on toxicities nor on anti-lymphoma activity of CAR-T.

Endothelial Dysfunction after Hematopoietic Stem Cell Transplantation: A Review Based on Physiopathology

Endothelial dysfunction (ED) is frequently encountered in transplant medicine. ED is an argument of high complexity, and its understanding requires a wide spectrum of knowledge based on many fields of basic sciences such as molecular biology, immunology, and pathology. After hematopoietic stem cell transplantation (HSCT), ED participates in the pathogenesis of various complications such as sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD), graft-versus-host disease (GVHD), transplant-associated thrombotic microangiopathy (TA-TMA), idiopathic pneumonia syndrome (IPS), capillary leak syndrome (CLS), and engraftment syndrome (ES). In the first part of the present manuscript, we briefly review some biological aspects of factors involved in ED: adhesion molecules, cytokines, Toll-like receptors, complement, angiopoietin-1, angiopoietin-2, thrombomodulin, high-mobility group B-1 protein, nitric oxide, glycocalyx, coagulation cascade. In the second part, we review the abnormalities of these factors found in the ED complications associated with HSCT. In the third part, a review of agents used in the treatment of ED after HSCT is presented.

BCMA CAR-T Therapy Is Safe and Effective for Refractory/Relapsed Multiple Myeloma With Central Nervous System Involvement

Central nervous system (CNS) involvement is a rare complication of multiple myeloma (MM) that portends an extremely poor prognosis. Although chimeric antigen receptor (CAR)-T cell therapy is considered a promising strategy for patients with MM, the role of CAR-T cell therapy in MM involving the CNS has not been fully elucidated. In this study, we retrospectively analyzed 4 cases of B-cell maturation antigen CAR-T cell therapy for patients with relapsed/refractory MM involving the CNS. Patients received a range of 2-7 lines of prior therapy, including 1 autologous hematopoietic stem cell transplant. The most common adverse event was cytokine release syndrome, which was observed in all 4 patients, including 2 with grade 1 and 2 with grade 2. No patient was complicated with immune effector cell-associated neurotoxicity syndrome. Within the follow-up (median: 257 d, range: 116-392 d), 3 of 4 patients reached complete remission (CR), and 1 patient reached partial response. At the data cutoff, 1 patient continued to remain in CR at day 220, and the patient with partial response died at day 116. The other 2 patients relapsed at 317 and 111 days with CR durations of 287 and 81 days, respectively. Our results show promising effectiveness and acceptable safety of CAR-T cell therapy for heavily pretreated patients with CNS MM.

Early vascular endothelial complications after hematopoietic cell transplantation: Role of the endotheliopathy in biomarkers and target therapies development

This work aims to review the role of endothelial dysfunction underlying the main complications appearing early after autologous and allogeneic hematopoietic cell transplantation (HCT). The endothelial damage as the pathophysiological substrate of sinusoidal obstruction syndrome (SOS) is well established. However, there is growing evidence of the involvement of endothelial dysfunction in other complications, such as acute graft-versus-host disease (aGVHD) and transplant-associated thrombotic microangiopathy (TA-TMAs). Moreover, HCT-related endotheliopathy is not only limited to the HCT setting, as there is increasing evidence of its implication in complications derived from other cellular therapies. We also review the incidence and the risk factors of the main HCT complications and the biological evidence of the endothelial involvement and other linked pathways in their development. In addition, we cover the state of the art regarding the potential use of the biomarkers of endotheliopathy in the prediction, the early diagnosis, and the follow-up of the HCT complications and summarize current knowledge points to the endothelium and the other linked pathways described as potential targets for the prevention and treatment of HCT-complications. Lastly, the endothelium-focused therapeutic strategies that are emerging and might have a potential impact on the survival and quality of life of post-HCT-patients are additionally reviewed.

Brain capillary obstruction during neurotoxicity in a mouse model of anti-CD19 chimeric antigen receptor T-cell therapy

Immunotherapy for haematologic malignancies with CD19-directed chimeric antigen receptor T cells has been highly successful at eradicating cancer but is associated with acute neurotoxicity in ∼40% of patients. This neurotoxicity correlates with systemic cytokine release syndrome, endothelial activation and disruption of endothelial integrity, but it remains unclear how these mechanisms interact and how they lead to neurologic dysfunction. We hypothesized that dysfunction of the neurovascular unit is a key step in the development of neurotoxicity. To recapitulate the interaction of the intact immune system with the blood-brain barrier, we first developed an immunocompetent mouse model of chimeric antigen receptor T-cell treatment-associated neurotoxicity. We treated wild-type mice with cyclophosphamide lymphodepletion followed by escalating doses of murine CD19-directed chimeric antigen receptor T cells. Within 3-5 days after chimeric antigen receptor T-cell infusion, these mice developed systemic cytokine release and abnormal behaviour as measured by daily neurologic screening exams and open-field testing. Histologic examination revealed widespread brain haemorrhages, diffuse extravascular immunoglobulin deposition, loss of capillary pericyte coverage and increased prevalence of string capillaries. To measure any associated changes in cerebral microvascular blood flow, we performed in vivo two-photon imaging through thinned-skull cranial windows. Unexpectedly, we found that 11.9% of cortical capillaries were plugged by Day 6 after chimeric antigen receptor T-cell treatment, compared to 1.1% in controls treated with mock transduced T cells. The capillary plugs comprised CD45+ leucocytes, a subset of which were CD3+ T cells. Plugging of this severity is expected to compromise cerebral perfusion. Indeed, we found widely distributed patchy hypoxia by hypoxyprobe immunolabelling. Increased serum levels of soluble ICAM-1 and VCAM-1 support a putative mechanism of increased leucocyte-endothelial adhesion. These data reveal that brain capillary obstruction may cause sufficient microvascular compromise to explain the clinical phenotype of chimeric antigen receptor T-cell neurotoxicity. The translational impact of this finding is strengthened by the fact that our mouse model closely approximates the kinetics and histologic findings of the chimeric antigen receptor T-cell neurotoxicity syndrome seen in human patients. This new link between systemic immune activation and neurovascular unit injury may be amenable to therapeutic intervention.

Cancer immunotherapy: Challenges and limitations

Although cancer immunotherapy has taken center stage in mainstream oncology inducing complete and long-lasting tumor regression, only a subset of patients receiving treatment respond and others relapse after an initial response. Different tumor types respond differently, and even in cancer types that respond (hot tumors), we still observe tumors that are unresponsive (cold tumors), suggesting the presence of resistance. Hence, the development of intrinsic or acquired resistance is a big challenge for the cancer immunotherapy field. Resistance to immunotherapy, including checkpoint inhibitors, CAR-T cell therapy, oncolytic viruses, and recombinant cytokines arises due to cancer cells employing several mechanisms to evade immunosurveillance.

Mechanisms of cytokine release syndrome and neurotoxicity of CAR T-cell therapy and associated prevention and management strategies

Chimeric antigen receptor (CAR) T-cell therapy has yielded impressive outcomes and transformed treatment algorithms for hematological malignancies. To date, five CAR T-cell products have been approved by the US Food and Drug Administration (FDA). Nevertheless, some significant toxicities pose great challenges to the development of CAR T-cell therapy, most notably cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Understanding the mechanisms underlying these toxicities and establishing prevention and treatment strategies are important. In this review, we summarize the mechanisms underlying CRS and ICANS and provide potential treatment and prevention strategies.

Optimizing the Clinical Impact of CAR-T Cell Therapy in B-Cell Acute Lymphoblastic Leukemia: Looking Back While Moving Forward

Chimeric antigen receptor T-cell (CAR-T) therapy has been successful in creating extraordinary clinical outcomes in the treatment of hematologic malignancies including relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). With several FDA approvals, CAR-T therapy is recognized as an alternative treatment option for particular patients with certain conditions of B-ALL, diffuse large B-cell lymphoma, mantle cell lymphoma, follicular lymphoma, or multiple myeloma. However, CAR-T therapy for B-ALL can be surrounded by challenges such as various adverse events including the life-threatening cytokine release syndrome (CRS) and neurotoxicity, B-cell aplasia-associated hypogammaglobulinemia and agammaglobulinemia, and the alloreactivity of allogeneic CAR-Ts. Furthermore, recent advances such as improvements in media design, the reduction of ex vivo culturing duration, and other phenotype-determining factors can still create room for a more effective CAR-T therapy in R/R B-ALL. Herein, we review preclinical and clinical strategies with a focus on novel studies aiming to address the mentioned hurdles and stepping further towards a milestone in CAR-T therapy of B-ALL.

Phase I study of CBM.CD19 chimeric antigen receptor T cell in the treatment of refractory diffuse large B-cell lymphoma in Chinese patients

Anti-CD19 chimeric antigen receptor (CAR) T cell therapy has shown impressive efficacy in treating B-cell malignancies. A single-center phase I dose-escalation study was conducted to evaluate the safety and efficacy of T cells transduced with CBM.CD19 CAR, a second-generation anti-CD19 CAR bearing 4-1BB costimulatory molecule, for the treatment of patients with refractory diffuse large B-cell lymphoma (DLBCL). Ten heavily treated patients with refractory DLBCL were given CBM.CD19 CAR-T cell (C-CAR011) treatment. The overall response rate was 20% and 50% at 4 and 12 weeks after the infusion of C-CAR011, respectively, and the disease control rate was 60% at 12 weeks after infusion. Treatment-emergent adverse events occurred in all patients. The incidence of cytokine release syndrome in all grades and grade ⩾ 3 was 90% and 0, respectively, which is consistent with the safety profile of axicabtagene ciloleucel and tisagenlecleucel. Neurotoxicity or other dose-limiting toxicities was not observed in any dose cohort of C-CAR011 therapy. Antitumor efficacy was apparent across dose cohorts. Therefore, C-CAR011 is a safe and effective therapeutic option for Chinese patients with refractory DLBCL, and further large-scale clinical trials are warranted.

Pembrolizumab for the treatment of progressive multifocal leukoencephalopathy following anti‐CD19 CAR‐T therapy: a case report

Progressive multifocal leukoencephalopathy (PML) is an opportunistic brain infection with few treatment options and poor survival when reversal of the underlying immune dysfunction is not achievable. JC polyomavirus reactivation resulting in PML can rarely complicate chimeric antigen receptor T‐cell (CAR‐T) therapy. We describe successful treatment of PML with Programmed death‐1 (PD‐1) blockade using pembrolizumab, 4 months following axicabtagene ciloleucel. Radiological features of immune reconstitution inflammatory syndrome without clinical deterioration were seen. Evidence of anti‐viral immune reconstitution by in vitro detection of JC‐specific T‐cells and sustained neurological recovery in this patient suggest PD‐1 blockade may be an effective treatment approach for PML post‐CAR‐T.

Non-invasive cell-tracking methods for adoptive T cell therapies

Adoptive T cell therapies (ACT) have demonstrated groundbreaking results in blood cancers and melanoma. Nevertheless, their significant cost, the occurrence of severe adverse events, and their poor performance in solid tumors are important hurdles hampering more widespread applicability. In vivo cell tracking allows instantaneous and non-invasive monitoring of the distribution, tumor homing, persistence, and redistribution to other organs of infused T cells in patients. Furthermore, cell tracking could aid in the clinical management of patients, allowing the detection of non-responders or severe adverse events at an early stage. This review provides a concise overview of the main principles and potential of cell tracking, followed by a discussion of the clinically relevant labeling strategies and their application in ACT.

Nonclinical safety assessment of engineered T cell therapies

Over the last decade, immunotherapy has established itself as an important novel approach in the treatment of cancer, resulting in a growing importance in oncology. Engineered T cell therapies, namely chimeric antigen receptor (CAR) T cells and T cell receptor (TCR) T cell therapies, are platform technologies that have enabled the development of products with remarkable efficacy in several hematological malignancies and are thus the focus of intense research and development activity. While engineered T cell therapies offer promise in addressing currently intractable cancers, they also present unique challenges, including their nonclinical safety assessment. A workshop organized by HESI and the US Food and Drug Administration (FDA) was held to provide an interdisciplinary forum for representatives of industry, academia and regulatory authorities to share information and debate on current practices for the nonclinical safety evaluation of engineered T cell therapies. This manuscript leverages what was discussed at this workshop to provide an overview of the current important nonclinical safety assessment considerations for the development of these therapeutic modalities (cytokine release syndrome, neurotoxicity, on-target/off-tumor toxicities, off-target effects, gene editing or vector integration-associated genomic injury). The manuscript also discusses approaches used for hazard identification or risk assessment and provides a regulatory perspective on such aspects.

Neurologic Complications in Patients with Cancer

Neurologic symptoms are commonly seen in patients with cancer and can be among the most challenging to diagnose and manage. It is often difficult to determine if new neurologic symptoms are secondary to direct effects of a malignant lesion, systemic complications of disease, paraneoplastic disorders, or side effects of cancer treatment itself. However, early diagnosis and treatment of each of these conditions can improve patients' quality of life and long-term functional outcomes. In this review, we describe a systematic approach to the diagnosis of new neurologic symptoms in patients with known malignancy. We have categorized the neurologic complications of cancer through a mechanistic approach, with an emphasis on ascertaining underlying pathophysiology to guide treatment choice. This review focuses on the acute neurologic complications of cancer that require hospital admission.

Quantitative radio-thin-layer chromatography and positron emission tomography studies for measuring streptavidin transduced chimeric antigen receptor T cells

The proliferation of chimeric antigen receptor (CAR) T cells is closely related to their efficacy, but it is still a great challenge to monitor and quantify CAR T cells in vivo. Based on the high affinity (Kd ≈ 10^-15 M) of streptavidin (SA) and biotin, radiolabeled biotin may be used to quantify SA-transduced CAR T cells (SA-CAR T cells). Radio-thin-layer chromatography (radio-TLC) and positron emission tomography (PET) are highly sensitive for trace analysis. Our aim was to develop radio-TLC and PET methods to quantify SA-CAR T cells in vitro and in vivo. First, we developed [⁶⁸Ga]-DOTA-biotin. Commercially available SA was used as a standard, and quantitative standard curves were established in vitro and in vivo by radio-TLC and PET. Furthermore, the feasibility of the method was verified in Raji model mice. The linear range of radio-TLC was 0.02 ∼ 0.15 pmol/μL with R² = 0.9993 in vitro. The linear range of PET was 0.02 ∼ 0.76 pmol/μL with R² = 0.9986 in vivo. SA in CAR T cells can also be accurately quantified in a Raji leukemia model according to PET imaging. The radio-TLC/PET method established in this study is promising for using in the dynamic monitoring and analysis of SA-CAR T cells during therapy.

CD19-targeted chimeric antigen receptor T-cell therapy for CNS relapsed or refractory acute lymphocytic leukaemia: a post-hoc analysis of pooled data from five clinical trials

BACKGROUND

CNS relapse of acute lymphocytic leukaemia is difficult to treat. Durable remissions of relapsed or refractory B-cell acute lymphocytic leukaemia have been observed following treatment with CD19-directed chimeric antigen receptor (CAR) T cells; however, most trials have excluded patients with active CNS disease. We aimed to assess the safety and activity of CAR T-cell therapy in patients with a history of CNS relapsed or refractory B-cell acute lymphocytic leukaemia.

METHODS

In this post-hoc analysis, we included 195 patients (aged 1-29 years; 110 [56%] male and 85 [44%] female) with relapsed or refractory CD19-positive acute lymphocytic leukaemia or lymphocytic lymphoma from five clinical trials (Pedi CART19, 13BT022, ENSIGN, ELIANA, and 16CT022) done at the Children's Hospital of Philadelphia (Philadelphia, PA, USA), in which participants received CD19-directed CAR T-cell therapy between April 17, 2012, and April 16, 2019. The trials required control of CNS disease at enrolment and infusion and excluded treatment in the setting of acute neurological toxic effects (>grade 1 in severity) or parenchymal lesions deemed to increase the risk of neurotoxicity. 154 patients from Pedi CART19, ELIANA, ENSIGN, and 16CT022 received tisagenlecleucel and 41 patients from the 13BT022 trial received the humanised CD19-directed CAR, huCART19. We categorised patients into two strata on the basis of CNS status at relapse or within the 12 months preceding CAR T-cell infusion-either CNS-positive or CNS-negative disease. Patients with CNS-positive disease were further divided on the basis of morphological bone marrow involvement-either combined bone marrow and CNS involvement, or isolated CNS involvement. Endpoints were the proportion of patients with complete response at 28 days after infusion, Kaplan-Meier analysis of relapse-free survival and overall survival, and the incidence of cytokine release syndrome and neurotoxicity.

FINDINGS

Of all 195 patients, 66 (34%) were categorised as having CNS-positive disease and 129 (66%) as having CNS-negative disease, and 43 (22%) were categorised as having isolated CNS involvement. The median length of follow-up was 39 months (IQR 25-49) in the CNS-positive stratum and 36 months (18-49) in the CNS-negative stratum. The proportion of patients in the CNS-positive stratum with a complete response at 28 days after infusion was similar to that in the CNS-negative stratum (64 [97%] of 66 vs 121 [94%] of 129; p=0·74), with no significant difference in relapse-free survival (60% [95% CI 49-74] vs 60% [51-71]; p=0·50) or overall survival (83% [75-93] vs 71% [64-79]; p=0·39) at 2 years between the two groups. Overall survival at 2 years was significantly higher in patients with isolated CNS involvement compared with those with bone marrow involvement (91% [82-100] vs 71% [64-78]; p=0·046). The incidence and severity of neurotoxicity (any grade, 53 [41%] vs 38 [58%]; grade 1, 24 [19%] vs 20 [30%]; grade 2, 14 [11%] vs 10 [15%]; grade 3, 12 [9%] vs 6 [9%], and grade 4, 3 [2%] vs 2 [3%]; p=0·20) and cytokine release syndrome (any grade, 110 [85%] vs 53 [80%]; grade 1, 12 [9%] vs 2 [3%]; grade 2, 61 [47%] vs 38 [58%]; grade 3, 18 [14%] vs 7 [11%] and grade 4, 19 [15%] vs 6 [9%]; p=0·26) did not differ between the CNS-negative and the CNS-positive disease strata.

INTERPRETATION

Tisagenlecleucel and huCART19 are active at clearing CNS disease and maintaining durable remissions in children and young adults with CNS relapsed or refractory B-cell acute lymphocytic leukaemia or lymphocytic lymphoma, without increasing the risk of severe neurotoxicity; although care should be taken in the timing of therapy and disease control to mitigate this risk. These preliminary findings support the use of these CAR T-cell therapies for patients with CNS relapsed or refractory B-cell acute lymphocytic leukaemia.

FUNDING

Children's Hospital of Philadelphia Frontier Program.

Neurologic complications in patients with lymphoid cancer

Neurologic complications of lymphoid cancer can be challenging to recognize and treat. The nervous system can be affected directly by hematogenous or local spread of lymphoma. Indirect neurologic effects of lymphoma include paraneoplastic syndromes and vascular complications. Lymphoma treatments can also cause neurologic complications. Early identification and treatment are crucial to stabilize or reverse neurologic deficits, prevent further nervous system injury, and to optimize overall oncologic therapy. This article provides an overview of different neurologic complications of lymphoma and its treatments, in addition to presentation of case studies that emphasize commonly encountered clinical scenarios.

Frontal predominant encephalopathy with early paligraphia as a distinctive signature of CAR T-cell therapy-related neurotoxicity

Chimeric antigen receptor (CAR) T-cell therapy is an emerging highly effective treatment for refractory haematological malignancies. Unfortunately, its therapeutic benefit may be hampered by treatment-related toxicities, including neurotoxicity. Early aggressive treatment is paramount to prevent neurological sequelae, yet it potentially interferes with the anti-cancer action of CAR T-cells. We describe four CAR T-cells infused patients who presented with reiterative writing behaviours, namely paligraphia, as an early manifestation of neurotoxicity, and eventually developed frontal predominant encephalopathy (one mild, three severe). Paligraphia may represent an early, specific, and easily detectable clinical finding of CAR T-cell therapy-related neurotoxicity, potentially informing its management.

Chimeric Antigen Receptor-T Cells: A Pharmaceutical Scope

Cancer is among the leading causes of death worldwide. Therefore, improving cancer therapeutic strategies using novel alternatives is a top priority on the contemporary scientific agenda. An example of such strategies is immunotherapy, which is based on teaching the immune system to recognize, attack, and kill malignant cancer cells. Several types of immunotherapies are currently used to treat cancer, including adoptive cell therapy (ACT). Chimeric Antigen Receptors therapy (CAR therapy) is a kind of ATC where autologous T cells are genetically engineered to express CARs (CAR-T cells) to specifically kill the tumor cells. CAR-T cell therapy is an opportunity to treat patients that have not responded to other first-line cancer treatments. Nowadays, this type of therapy still has many challenges to overcome to be considered as a first-line clinical treatment. This emerging technology is still classified as an advanced therapy from the pharmaceutical point of view, hence, for it to be applied it must firstly meet certain requirements demanded by the authority. For this reason, the aim of this review is to present a global vision of different immunotherapies and focus on CAR-T cell technology analyzing its elements, its history, and its challenges. Furthermore, analyzing the opportunity areas for CAR-T technology to become an affordable treatment modality taking the basic, clinical, and practical aspects into consideration.

Putting function back in dysfunction: Endothelial diseases and current therapies in hematopoietic stem cell transplantation and cellular therapies

Endothelial dysfunction is characterized by altered vascular permeability and prothrombotic, pro-inflammatory phenotypes. Endothelial dysfunction results in end-organ damage and has been associated with diverse disease pathologies. Complications observed after hematopoietic stem cell transplantation (HCT) and chimeric antigen receptor-T cell (CAR-T) therapy for hematologic and neoplastic disorders share overlapping clinical manifestations and there is increasing evidence linking these complications to endothelial dysfunction. Despite advances in supportive care and treatments, end-organ toxicity remains the leading cause of mortality. A new strategy to mitigate endothelial dysfunction could lead to improvement of clinical outcomes for patients. Statins have demonstrated pleiotropic effects of immunomodulatory and endothelial protection by various molecular mechanisms. Recent applications in immune-mediated diseases such as autoimmune disorders, chronic inflammatory conditions, and graft-versus-host disease (GVHD) have shown promising results. In this review, we cover the mechanisms underlying endothelial dysfunction in GVHD and CAR-T cell-related toxicities. We summarize the current knowledge about statins and other agents used as endothelial protectants. We propose further studies using statins for prophylaxis and prevention of end-organ damage related to extensive endothelial dysfunction in HCT and CAR-T.

Real-World Experiences of CAR T-Cell Therapy for Large B-Cell Lymphoma: How Similar Are They to the Prospective Studies?

Chimeric antigen receptor (CAR) T cell therapy has emerged as a revolutionary treatment option for highly aggressive B cell malignancies. Clinical trials of CD19 CAR T cells for the management of relapsed and/or refractory non-Hodgkin lymphoma (NHL) have shown markedly improved survival and response rates. The goal of this review is to evaluate whether the results from these clinical trials are reflective of real-world practices through the analysis of published literature of the commercially available CAR T cell products. We have found that despite the significantly different patient characteristics, the adverse events and response rates of real-world patients were similar to those of the clinical trials. Of interest, several groups excluded from the clinical trials, such as patients with HIV infection, chronic viral hepatitis, and secondary CNS (central nervous system) lymphoma, had case reports of promising outcomes.

Prophylactic corticosteroid use in patients receiving axicabtagene ciloleucel for large B-cell lymphoma

ZUMA‐1 (NCT02348216) examined the safety and efficacy of axicabtagene ciloleucel (axi‐cel), an autologous CD19‐directed chimaeric antigen receptor (CAR)‐T cell therapy, in refractory large B‐cell lymphoma. To reduce treatment‐related toxicity, several exploratory safety management cohorts were added to ZUMA‐1. Specifically, cohort 6 investigated management of cytokine release syndrome (CRS) and neurologic events (NEs) with prophylactic corticosteroids and earlier corticosteroid and tocilizumab intervention. CRS and NE incidence and severity were primary end‐points. Following leukapheresis, patients could receive optional bridging therapy per investigator discretion. All patients received conditioning chemotherapy (days −5 through −3), 2 × 10⁶ CAR‐T cells/kg (day 0) and once‐daily oral dexamethasone [10 mg, day 0 (before axi‐cel) through day 2]. Forty patients received axi‐cel. CRS occurred in 80% of patients (all grade ≤2). Any grade and grade 3 or higher NEs occurred in 58% and 13% of patients respectively. Sixty‐eight per cent of patients did not experience CRS or NEs within 72 h of axi‐cel. With a median follow‐up of 8·9 months, objective and complete response rates were 95% and 80% respectively. Overall, prophylactic corticosteroids and earlier corticosteroid and/or tocilizumab intervention resulted in no grade 3 or higher CRS, a low rate of grade 3 or higher NEs and high response rates in this study population.

EEG findings in CART T associated neurotoxicity: clinical and radiological correlations

BACKGROUND

While EEG is frequently reported as abnormal after CAR T cell therapy, its clinical significance remains unclear. We aim to systematically describe EEG features in a large single-center cohort and correlate them with clinical and radiological findings.

METHODS

We retrospectively identified patients undergoing CAR T cell therapy who had continuous EEG. Neurotoxicity grades, detailed neurological symptoms, and brain MRI or FDG-PET were obtained. Correlation between clinical and radiological findings and EEG features was assessed.

RESULTS

In 81 patients with median neurotoxicity grade 3 (IQR 2-3), diffuse EEG background slowing was the most common finding and correlated with neurotoxicity severity (p <0.001). A total of 42 patients had rhythmic or periodic patterns, 16 of them within the ictal-interictal-continuum (IIC), 5 with clinical seizures, and 3 with only electrographic seizures. Focal EEG abnormalities, consisting of lateralized periodic discharges (LPD, n=1), lateralized rhythmic delta activity (LRDA, n=6), or focal slowing (n=19), were found in 22 patients. All patients with LRDA, LPD, and 10/19 patients with focal slowing had focal clinical symptoms concordant with these EEG abnormalities. In addition, these focal EEG changes often correlated with PET hypometabolism or MRI hypoperfusion, in absence of a structural lesion.

CONCLUSION

In adult patients experiencing neurotoxicity after CAR T cell infusion, EEG degree of background disorganization correlated with neurotoxicity severity. IIC patterns and focal EEG abnormalities are frequent and often correlate with focal clinical symptoms and with PET-hypometabolism/MRI-hypoperfusion, without structural lesion. The etiology of these findings remains to be elucidated.

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.

Optimization of CAR-T Cell-Based Therapies Using Small-Molecule-Based Safety Switches

Chimeric antigen receptor T cell therapy has demonstrated antileukemia efficacy. However, this therapeutic approach is hampered by severe cytokine release syndrome, which is a major impediment to its widespread application in the clinic. The safety of this approach can be improved by engineering a rapid and reversible "off" or "on" safety switch for CAR-T cells. Cutting-edge investigations combining the advantages of genetic engineering and chemical technology have led to the invention of small-molecule-based safety switches for CAR-T cells. Small molecules such as FITC, folate, rimiducid, rapamycin, proteolysis-targeting chimera (PROTAC) compounds, and dasatinib are being investigated to design such safety switches. Optimized CAR-T cells may have enhanced therapeutic efficiency with fewer adverse effects. Herein we summarize and classify current novel small-molecule-based safety switches for CAR-T cells that aim to provide pharmacological control over the activities and toxicities associated with CAR-T cell-based cancer immunotherapies.

Neurological Immunotoxicity from Cancer Treatment

The emergence of immune-based treatments for cancer has led to a growing field dedicated to understanding and managing iatrogenic immunotoxicities that arise from these agents. Immune-related adverse events (irAEs) can develop as isolated events or as toxicities affecting multiple body systems. In particular, this review details the neurological irAEs from immune checkpoint inhibitors (ICI) and chimeric antigen receptor (CAR) T cell immunotherapies. The recognition and treatment of neurological irAEs has variable success, depending on the severity and nature of the neurological involvement. Understanding the involved mechanisms, predicting those at higher risk for irAEs, and establishing safety parameters for resuming cancer immunotherapies after irAEs are all important fields of ongoing research.