Clinical and Biological Correlates of Neurotoxicity Associated with CAR T-cell Therapy in Patients with B-cell Acute Lymphoblastic Leukemia

Current and future concepts for the generation and application of genetically engineered CAR-T and TCR-T cells

Adoptive cell therapy (ACT) has seen a steep rise of new therapeutic approaches in its immune-oncology pipeline over the last years. This is in great part due to the recent approvals of chimeric antigen receptor (CAR)-T cell therapies and their remarkable efficacy in certain soluble tumors. A big focus of ACT lies on T cells and how to genetically modify them to target and kill tumor cells. Genetically modified T cells that are currently utilized are either equipped with an engineered CAR or a T cell receptor (TCR) for this purpose. Both strategies have their advantages and limitations. While CAR-T cell therapies are already used in the clinic, these therapies face challenges when it comes to the treatment of solid tumors. New designs of next-generation CAR-T cells might be able to overcome these hurdles. Moreover, CARs are restricted to surface antigens. Genetically engineered TCR-T cells targeting intracellular antigens might provide necessary qualities for the treatment of solid tumors. In this review, we will summarize the major advancements of the CAR-T and TCR-T cell technology. Moreover, we will cover ongoing clinical trials, discuss current challenges, and provide an assessment of future directions within the field.

Combining chemotherapy with CAR-T cell therapy in treating solid tumors

Chemotherapy has long been a standard treatment for a wide range of malignancies, where patients typically undergo multiple rounds of chemotherapy regimens to control tumor growth. In the clinic, the chemotherapy drugs cyclophosphamide and fludarabine are commonly used prior to Chimeric Antigen Receptor T (CAR-T) cell therapy to lymphodeplete and improve CAR-T cell engraftment. In this review, we discuss the use of chemotherapy in combination with CAR-T cell therapy. We also show that chemotherapy can deplete immunosuppressive cells, promote a pro-inflammatory tumor microenvironment, disrupt tumor stroma, and improve CAR-T cell recruitment to the tumor. Although the combination of chemotherapy plus CAR-T cell therapy is promising, certain aspects of chemotherapy also pose a challenge. In addition, the combined therapeutic effect may be heavily dependent on the dose and the treatment schedule. Thus, we also discussed the obstacles to effective clinical outcomes of the combination therapy.

Safety evaluation of axicabtagene ciloleucel for relapsed or refractory large B-cell lymphoma

INTRODUCTION

CD19-directed chimeric antigen receptor (CAR) T-cell therapy is a highly effective therapy for patients with relapsed/refractory large B-cell lymphoma (LBCL) and three CD19 CAR T-cell products (axicabtagene ciloleucel, tisagenlecleucel and lisocabtagene maraleucel) are currently approved for this indication. Despite the clinical benefit of CD19 directed CAR T-cell therapy, this treatment is associated with significant morbidity from treatment-emergent toxicities.

AREAS COVERED

This Review discusses the safety considerations of axicabtagene ciloleucel in patients with LBCL. This includes discussion of the frequently observed immune-mediated toxicities of cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome. Additionally, we review CAR T-cell therapy related cytopenias, infection, organ dysfunction and the more recently described hemophagocytic lymphohistiocytosis.

EXPERT OPINION

A thorough understanding of the toxicities associated with CD19-directed CAR T-cell therapy will facilitate the optimal selection of patients for this therapy. Furthermore, knowledge of preventative measures of CAR T-cell related complications, and early recognition and appropriate intervention will lead to the safe administration of these therapies, and ultimately improved outcomes for our patients.

Diabetes insipidus and Guillain-Barré-like syndrome following CAR-T cell therapy: a case report

BACKGROUND

Immune effector cell-associated neurotoxicity syndrome (ICANS) is a common adverse event of CD19-directed chimeric antigen receptor (CAR) T cell therapy. Other neurological adverse events, however, have not methodically been described and studied. Furthermore, safety data on CAR-T cell therapy in patients with central nervous system (CNS) lymphoma remain limited.

MAIN BODY

We here report occurrence of a Guillain-Barré-like syndrome (GBS) and central diabetes insipidus (cDI) following tisagenlecleucel therapy for relapsed high-grade lymphoma with CNS involvement. Both complications were refractory to standard treatment of ICANS. Weakness of respiratory muscles required mechanical ventilation and tracheostomy while cDI was treated with desmopressin substitution for several weeks. Muscle-nerve biopsy and nerve conduction studies confirmed an axonal pattern of nerve damage. T cell-rich infiltrates and detection of the CAR transgene in muscle-nerve sections imply a direct or indirect role of CAR-T cell-mediated inflammation. In line with current treatment guidelines for GBS, intravenous immunoglobulin was administered and gradual but incomplete recovery was observed over the course of several months.

CONCLUSIONS

This case report highlights the risk of rare but severe neurological adverse events, such as acute GBS or cDI, in patients treated with CAR-T cells. It further underlines the importance of appropriate patient surveillance and systematic reporting of rare complications to eventually improve treatment.

The current landscape of CAR T-cell therapy for solid tumors: Mechanisms, research progress, challenges, and counterstrategies

The successful outcomes of chimeric antigen receptor (CAR) T-cell therapy in treating hematologic cancers have increased the previously unprecedented excitement to use this innovative approach in treating various forms of human cancers. Although researchers have put a lot of work into maximizing the effectiveness of these cells in the context of solid tumors, few studies have discussed challenges and potential strategies to overcome them. Restricted trafficking and infiltration into the tumor site, hypoxic and immunosuppressive tumor microenvironment (TME), antigen escape and heterogeneity, CAR T-cell exhaustion, and severe life-threatening toxicities are a few of the major obstacles facing CAR T-cells. CAR designs will need to go beyond the traditional architectures in order to get over these limitations and broaden their applicability to a larger range of malignancies. To enhance the safety, effectiveness, and applicability of this treatment modality, researchers are addressing the present challenges with a wide variety of engineering strategies as well as integrating several therapeutic tactics. In this study, we reviewed the antigens that CAR T-cells have been clinically trained to recognize, as well as counterstrategies to overcome the limitations of CAR T-cell therapy, such as recent advances in CAR T-cell engineering and the use of several therapies in combination to optimize their clinical efficacy in solid tumors.

Novel pathophysiological insights into CAR-T cell associated neurotoxicity

Chimeric antigen receptor (CAR) T cell therapy represents a scientific breakthrough in the treatment of advanced hematological malignancies. It relies on cell engineering to direct the powerful cytotoxic T-cell activity toward tumor cells. Nevertheless, these highly powerful cell therapies can trigger substantial toxicities such as cytokine release syndrome (CRS) and immune cell-associated neurological syndrome (ICANS). These potentially fatal side effects are now better understood and managed in the clinic but still require intensive patient follow-up and management. Some specific mechanisms seem associated with the development of ICANS, such as cytokine surge caused by activated CAR-T cells, off-tumor targeting of CD19, and vascular leak. Therapeutic tools are being developed aiming at obtaining better control of toxicity. In this review, we focus on the current understanding of ICANS, novel findings, and current gaps.

It Is in the Eye of the Beholder: Ocular Ultrasound Enhanced Monitoring of Neurotoxicity after CAR-T Cell Therapy

Usually used in emergency settings, bedside sonographic measurement of optic nerve sheath diameter can aid in diagnosing elevated intracranial pressure. We report a case of a 26-year-old male hospitalized for CAR T-cell therapy with Axicabtagene Ciloleucel for treatment of relapsed diffuse large B-cell lymphoma, who developed progressive symptoms of immune effector cell-associated neurotoxicity syndrome. Fundoscopic examination suggested the presence of blurred optic disc margins. Bedside ocular ultrasound revealed wide optic nerve sheath diameters and bulging optic discs bilaterally. The patient had a ventriculostomy placed for monitoring and received treatment with steroids and mannitol, as well as tocilizumab. After 7 days in the ICU, the patient recovered with no evidence of long-term neurological deficits.

Chimeric antigen receptor T-cell therapy for multiple myeloma

Multiple myeloma (MM) is a malignant plasma cell disorder that remains incurable for most patients, as persistent clonal evolution drives new mutations which confer MM high-risk signatures and resistance to standard care. The past two decades have significantly refashioned the therapeutic options for MM, especially adoptive T cell therapy contributing to impressive response rate and clinical efficacy. Despite great promises achieved from chimeric antigen receptor T-cell (CAR-T) therapy, the poor durability and severe toxicity (cytokine release syndrome and neurotoxicity) are still huge challenges. Therefore, relapsed/refractory multiple myeloma (RRMM), characterized by the nature of clinicopathologic and molecular heterogeneity, is frequently associated with poor prognosis. B Cell Maturation Antigen (BCMA) is the most successful target for CAR-T therapy, and other potential targets either for single-target or dual-target CAR-T are actively being studied in numerous clinical trials. Moreover, mechanisms driving resistance or relapse after CAR-T therapy remain uncharacterized, which might refer to T-cell clearance, antigen escape, and immunosuppressive tumor microenvironment. Engineering CAR T-cell to improve both efficacy and safety continues to be a promising area for investigation. In this review, we aim to describe novel tumor-associated neoantigens for MM, summarize the data from current MM CAR-T clinical trials, introduce the mechanism of disease resistance/relapse after CAR-T infusion, highlight innovations capable of enhanced efficacy and reduced toxicity, and provide potential directions to optimize manufacturing processes.

Cross-study safety analysis of risk factors in CAR T cell clinical trials: An FDA database pilot project

The Chimeric Antigen Receptor (CAR) T Cell Safety Database Project explored the use of cross-study safety data to identify risk factors associated with severe cytokine release syndrome (sCRS) and severe neurological toxicities (sNTX) after CAR T cell administration. Sponsors voluntarily submitted data for 1,926 subjects from 17 phases 1 and 2 studies (six acute lymphocytic leukemia [ALL], five non-Hodgkin's lymphoma [NHL], and six multiple myeloma [MM] studies). Subjects with ALL had a higher risk for developing sCRS and sNTX compared with subjects with NHL or MM. Subjects who received CAR T cells produced with gammaretrovirus vectors including CD28 sequences had higher rates of sNTX compared with subjects who received products produced with other vector designs included in the database. Use of cytokine-directed therapies and corticosteroids at lower toxicity grades were associated with lower rates of sCRS. Although this exploratory study was limited by unadjusted cross-study comparisons, it independently reproduced known risk factors for CAR T cell toxicity. Findings provide stakeholders in the CAR T cell clinical development community information on safety trends for consideration in early phase clinical trial design, as well as avenues for additional research.

Endothelial activation predicts disseminated intravascular coagulopathy, cytokine release syndrome and prognosis in patients treated with anti‐CD19 CAR‐T cells

Cytokine release syndrome (CRS) and consumptive coagulopathy can complicate the treatment with chimeric antigen receptor T (CAR-T) cells. The modified version of the Endothelial Activation and Stress Index (mEASIX), a score derived from haematopoietic stem cell transplantation, combines platelets, C-reactive protein (CRP), and lactate dehydrogenase (LDH) and has been correlated with CRS and endothelial biomarkers. In 38 consecutive patients with aggressive lymphoproliferative disease we measured a coagulative laboratory panel at baseline and early after infusion of anti-CD19 CAR-T. The panel was investigated also in the presence of CRS graded 2 or higher, or immune effector cell-associated neurotoxicity syndrome (ICANS). Moreover, we examined the relationship between mEASIX, coagulation biomarkers, and toxicities of CAR-T cells. During CRS grade 2 or higher, we found increased prothrombin time (PT) and activated partial thromboplastin time (aPTT), fibrinogen, D-dimer, factor VIII (FVIII), and von Willebrand factor (vWF) antigen levels, and decreased platelet count and antithrombin levels. The occurrence of immune effector cell-associated neurotoxicity syndrome was associated with higher PT values, D-dimer, FVIII, and vWF levels, and decreased fibrinogen levels and platelet count. A higher mEASIX score correlated with increased aPTT values, fibrinogen, D-dimer, FVIII and vWF levels, and decreased antithrombin levels. Baseline mEASIX was predictive for consumptive coagulopathy and CRS graded 2 or higher, and for progression-free survival and overall survival.

Neurological Complications of Conventional and Novel Anticancer Treatments

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

Serious adverse events and coping strategies of CAR-T cells in the treatment of malignant tumors

Chimeric antigen receptor T (CAR-T) cells technology has been successfully used in the treatment of B cell-derived hematological tumors and multiple myeloma. CAR-T cells are also being studied in a variety of solid tumors. Current clinical reports on CAR-T cells in the treatment of malignant tumors are abundant. The tumor-killing activity of CAR-T cells and the unique adverse effects of CAR-T cells have been confirmed by many studies. There is evidence that serious adverse events can be life-threatening. CAR-T cells therapy is increasingly used in clinical settings, so it is important to pay attention to its serious adverse events. In this review, we summarized the serious adverse events of CAR-T cells in the treatment of malignant tumors by reading literature and searching relevant clinical studies, and discussed the management and treatment of serious adverse events in an effort to provide theoretical support for clinicians who deal with such patients.

Efficacy, Safety, and Challenges of CAR T-Cells in the Treatment of Solid Tumors

Immunotherapy has been the fifth pillar of cancer treatment in the past decade. Chimeric antigen receptor (CAR) T-cell therapy is a newly designed adoptive immunotherapy that is able to target and further eliminate cancer cells by engaging with MHC-independent tumor-antigens. CAR T-cell therapy has exhibited conspicuous clinical efficacy in hematological malignancies, but more than half of patients will relapse. Of note, the efficacy of CAR T-cell therapy has been even more disappointing in solid tumors. These challenges mainly include (1) the failures of CAR T-cells to treat highly heterogeneous solid tumors due to the difficulty in identifying unique tumor antigen targets, (2) the expression of target antigens in non-cancer cells, (3) the inability of CAR T-cells to effectively infiltrate solid tumors, (4) the short lifespan and lack of persistence of CAR T-cells, and (5) cytokine release syndrome and neurotoxicity. In combination with these characteristics, the ideal CAR T-cell therapy for solid tumors should maintain adequate T-cell response over a long term while sparing healthy tissues. This article reviewed the status, clinical application, efficacy, safety, and challenges of CAR T-cell therapies, as well as the latest progress of CAR T-cell therapies for solid tumors. In addition, the potential strategies to improve the efficacy of CAR T-cells and prevent side effects in solid tumors were also explored.

Hypophosphatemia Due to Increased Effector Cell Metabolic Activity Is Associated with Neurotoxicity Symptoms in CD19-Targeted CAR T-cell Therapy

A major complication of chimeric antigen receptor (CAR) T-cell therapy is immune effector cell-associated neurotoxicity syndrome (ICANS), which presents as aphasia, confusion, weakness, somnolence, seizures, and coma. This is similar to the neurologic manifestations of hypophosphatemia, which can result from sudden increases in metabolic demand for phosphorylated intermediates (e.g., refeeding syndrome and sepsis). Given these similarities, we investigated whether CAR T-cell effector metabolic activity is associated with increased extracellular phosphate consumption and a possible association between hypophosphatemia and ICANS. In vitro 4-1BB and CD28 CD19-targeted CAR T-cell effector activity was found to be associated with increased consumption of media phosphorus, which was temporally associated with increased single-cell effector secretomic activity and increased phosphorus-dependent metabolic demand of the CAR T cells. A clinical cohort of 77 patients treated with CD19-targeted CAR T-cell therapy demonstrated a significant anticorrelation between serum phosphorus and ICANS incidence and severity, with earlier onset of hypophosphatemia after CAR T-cell infusion more likely to result in neurotoxicity. These results imply phosphorous level monitoring could alert to the development of ICANS in clinical scenarios. See related Spotlight by Tobin et al., p. 1422.

Evaluating the Patient with Neurotoxicity after Chimeric Antigen Receptor T-cell Therapy

OPINION STATEMENT

Chimeric antigen receptor (CAR) T-cells are now a well-established treatment for hematologic malignancies. Their use in clinical practice has expanded quite rapidly and hospitals have developed CAR T-cell protocols to evaluate patients for associated toxicities, and particularly for neurotoxicity. There are many variables that influence the risk for developing this complication, many of which are not fully understood. The severity can be related to a particular product. Clinical vigilance is critical to facilitate early recognition of neurotoxicity, hence the importance of pre-CAR T-cell neurological evaluation of each patient. While details of such an evaluation may slightly differ between institutions, generally a comprehensive neurological evaluation including assessment of cognitive abilities along with magnetic resonance imaging (MRI) of the brain is a gold standard. Management of neurotoxicity requires a well-orchestrated team approach with specialists from oncology, neurology, oftentimes neurosurgery and neuro-intensive care. Diagnostic work-up frequently includes detailed neurologic evaluation with comparison to the baseline assessment, imaging of the brain, electroencephalogram, and lumbar puncture. While steroids are uniformly used for treatment, many patients also receive tocilizumab for an underlying and frequently concomitant cytokine release syndrome (CRS) in addition to symptom-driven supportive care. Novel CAR T-cell constructs and other agents allowing for potentially lower risk of toxicity are being explored. While neurotoxicity is predominantly an early, and reversible, event, a growing body of literature suggests that late neurotoxicity with variable clinical presentation can also occur.

Phase I CAR-T Clinical Trials Review

BACKGROUND/AIM

Chimeric antigen receptor (CAR) T cells with tumor specificity are being increasingly investigated. Phase I trials are the first step of testing for safety of novel CAR-T therapy to determine the maximum tolerated dose (MTD). Several dose escalation methods have been developed over time including rule-based, model-based, and model-assisted designs. The goal of this project is to overview the phase I designs used in current CAR-T trials.

MATERIALS AND METHODS

We searched PubMed for peer-reviewed literature published between January 1, 2015 and December 31, 2021. The search was limited to human studies in the English language using the keywords "CAR-T phase I", "clinical trials", and "full text".

RESULTS

One hundred nine papers with at least partial phase I components were included for analysis. 31.2% of the trials used the traditional 3+3 or a variation of said design, and 60.6% did not mention the dose escalation design. The majority of the manuscripts (59.6%) did not report cohort size while 19.3% did not specify the timing of evaluation. Although most of the studies were registered with CT.gov, only 33.9% had any results submitted or posted to CT.gov These trends persisted even in manuscripts published in journals with high impact factors.

CONCLUSION

Standardizing the publication criteria and providing basic elements of phase I clinical trials are critical to ensure high quality of manuscripts. With the quick development and high costs of CAR-T cell therapy, adoption of advanced designs such as model-based and model-assisted should increase to improve efficiency of clinical trials.

Chimeric Antigen Receptor T-cell Therapy in Hematologic Malignancies and Patient-reported Outcomes: A Scoping Review

The inclusion of patient-reported outcome (PRO) measures in chimeric antigen receptor (CAR) T-cell therapy research is critical for understanding the impact of this novel approach from a unique patient standpoint. We performed a scoping review to map the available literature on the use of PRO measures in CAR T-cell therapy studies of patients with hematologic malignancies published between January 2015 and July 2022. Fourteen studies were identified, of which 7 (50%) were investigational early-phase trials, 6 (42.9%) were observational studies, and 1 (7.1%) was a pilot study. The EQ-5D and the PROMIS-29 were the 2 most frequently used PRO measures, being included in 6 (42.9%) and 5 (35.7%) studies, respectively. Despite differences in study designs, there seems to be evidence of improvements over time since CAR T-cell infusion in important domains such as physical functioning and fatigue, at least in patients who respond to therapy. Overall, the studies identified in our review have shown the added value of PRO assessment in CAR T-cell therapy research by providing novel information that complements the knowledge on safety and efficacy. However, there are several questions which remain to be answered in future research. For example, limited evidence exists regarding patient experience during important phases of the disease trajectory as only 4 (28.6%) and 5 (35.7%) studies provided information on PROs during the first 2 weeks from CAR T-cell infusion and after the first year, respectively. Time is ripe for a more systematic implementation of high-quality PRO assessment in future clinical trials and in real-life settings of patients treated with CAR T-cell therapy.

Forecasting immune effector cell-associated neurotoxicity syndrome after chimeric antigen receptor t-cell therapy

BACKGROUND

Immune effector cell-associated neurotoxicity syndrome (ICANS) is a clinical and neuropsychiatric syndrome that can occur days to weeks following administration chimeric antigen receptor (CAR) T-cell therapy. Manifestations of ICANS range from encephalopathy and aphasia to cerebral edema and death. Because the onset and time course of ICANS is currently unpredictable, prolonged hospitalization for close monitoring following CAR T-cell infusion is a frequent standard of care.

METHODS

This study was conducted at Brigham and Women's Hospital from April 2015 to February 2020. A cohort of 199 hospitalized patients treated with CAR T-cell therapy was used to develop a combined hidden Markov model and lasso-penalized logistic regression model to forecast the course of ICANS. Model development was done using leave-one-patient-out cross validation.

RESULTS

Among the 199 patients included in the analysis 133 were male (66.8%), and the mean (SD) age was 59.5 (11.8) years. 97 patients (48.7%) developed ICANS, of which 59 (29.6%) experienced severe grades 3-4 ICANS. Median time of ICANS onset was day 9. Selected clinical predictors included maximum daily temperature, C reactive protein, IL-6, and procalcitonin. The model correctly predicted which patients developed ICANS and severe ICANS, respectively, with area under the curve of 96.7% and 93.2% when predicting 5 days ahead, and area under the curve of 93.2% and 80.6% when predicting the entire future risk trajectory looking forward from day 5. Forecasting performance was also evaluated over time horizons ranging from 1 to 7 days, using metrics of forecast bias, mean absolute deviation, and weighted average percentage error.

CONCLUSION

The forecasting model accurately predicts risk of ICANS following CAR T-cell infusion and the time course ICANS follows once it has begun.Cite Now.

Pediatric versus adult high grade glioma: Immunotherapeutic and genomic considerations

High grade gliomas are identified as malignant central nervous tumors that spread rapidly and have a universally poor prognosis. Historically high grade gliomas in the pediatric population have been treated similarly to adult high grade gliomas. For the first time, the most recent classification of central nervous system tumors by World Health Organization has divided adult from pediatric type diffuse high grade gliomas, underscoring the biologic differences between these tumors in different age groups. The objective of our review is to compare high grade gliomas in the adult versus pediatric patient populations, highlighting similarities and differences in epidemiology, etiology, pathogenesis and therapeutic approaches. High grade gliomas in adults versus children have varying clinical presentations, molecular biology background, and response to chemotherapy, as well as unique molecular targets. However, increasing evidence show that they both respond to recently developed immunotherapies. This review summarizes the distinctions and commonalities between the two in disease pathogenesis and response to therapeutic interventions with a focus on immunotherapy.

EEG-based grading of immune effector cell-associated neurotoxicity syndrome

CAR-T cell therapy is an effective cancer therapy for multiple refractory/relapsed hematologic malignancies but is associated with substantial toxicity, including Immune Effector Cell Associated Neurotoxicity Syndrome (ICANS). Improved detection and assessment of ICANS could improve management and allow greater utilization of CAR-T cell therapy, however, an objective, specific biomarker has not been identified. We hypothesized that the severity of ICANS can be quantified based on patterns of abnormal brain activity seen in electroencephalography (EEG) signals. We conducted a retrospective observational study of 120 CAR-T cell therapy patients who had received EEG monitoring. We determined a daily ICANS grade for each patient through chart review. We used visually assessed EEG features and machine learning techniques to develop the Visual EEG-Immune Effector Cell Associated Neurotoxicity Syndrome (VE-ICANS) score and assessed the association between VE-ICANS and ICANS. We also used it to determine the significance and relative importance of the EEG features. We developed the Visual EEG-ICANS (VE-ICANS) grading scale, a grading scale with a physiological basis that has a strong correlation to ICANS severity (R = 0.58 [0.47-0.66]) and excellent discrimination measured via area under the receiver operator curve (AUC = 0.91 for ICANS ≥ 2). This scale shows promise as a biomarker for ICANS which could help to improve clinical care through greater accuracy in assessing ICANS severity.

Radiotherapy plus CAR-T cell therapy to date: A note for cautions optimism?

Radiotherapy (RT) is a traditional therapeutic regime that focuses on ionizing radiation, however, RT maintains largely palliative due to radioresistance. Factors such as hypoxia, the radiosensitivity of immune cells, and cancer stem cells (CSCs) all come into play in influencing the significant impact of radioresistance in the irradiated tumor microenvironment (TME). Due to the substantial advances in the treatment of malignant tumors, a promising approach is the genetically modified T cells with chimeric antigen receptors (CARs) to eliminate solid tumors. Moreover, CAR-T cells targeting CSC-related markers would eliminate radioresistant solid tumors. But solid tumors that support an immune deserted TME, are described as immunosuppressive and typically fail to respond to CAR-T cell therapy. And RT could overcome these immunosuppressive features; thus, growing evidence supports the combination of RT with CAR-T cell therapy. In this review, we provide a deep insight into the radioresistance mechanisms, advances, and barriers of CAR-T cells in response to solid tumors within TME. Therefore, we focus on how the combination strategy can be used to eliminate these barriers. Finally, we show the challenges of this therapeutic partnership.

Switchable targeting of solid tumors by BsCAR T cells

The development of chimeric antigen receptor (CAR) T cell therapy has become a critical milestone in modern oncotherapy. Despite the remarkable in vitro effectiveness, the problem of safety and efficacy of CAR T cell therapy against solid tumors is challenged by the lack of tumor-specific antigens required to avoid on-target off-tumor effects. Spatially separating the cytotoxic function of CAR T cells from tumor antigen recognition provided by protein mediators allows for the precise control of CAR T cell cytotoxicity. Here, the high affinity and capability of the bacterial toxin-antitoxin barnase-barstar system were adopted to guide CAR T cells to solid tumors. The complementary modules based on (1) ankyrin repeat (DARPin)-barnase proteins and (2) barstar-based CAR (BsCAR) were designed to provide switchable targeting to tumor cells. The alteration of the DARPin-barnase switches enabled the targeting of different tumor antigens with a single BsCAR. A gradual increase in cytokine release and tunable BsCAR T cell cytotoxicity was achieved by varying DARPin-barnase loads. Switchable BsCAR T cell therapy was able to eradicate the HER2+ ductal carcinoma in vivo. Guiding BsCAR T cells by DARPin-barnase switches provides a universal approach for a controlled multitargeted adoptive immunotherapy.

Adénocarcinome œsogastrique – nouvelles cibles thérapeutiques

The median overall survival of metastatic esophagogastric adenocarcinoma is approximately twelve months. In fifteen years, major breakthrough have been the targeting of HER2 overexpression and more recently immunotherapy in patients with CPS≥5. Recent advances in molecular biology have identified some molecular alterations in esophageal adenocarcinoma, interesting to target. FGFR2 is overexpressed in one third of patients, and its targeting with a specific monoclonal antibody bemarituzumab showed a significant improvement in survival. Claudin 18.2 (CLDN 18.2) is overexpressed in at least a third of esophagogastric adenocarcinomas. The combination of zolbetuximab and chemotherapy provides a survival benefit, correlated with the intensity of CLDN 18.2 expression. The potential interest of targeting other pathways is under investigation in several trials with some encouraging preliminary data, and early trials in these indications, justifying considering large molecular screening in patients who might be candidate for early phase trial. Finally, with the recent advent of immunotherapy, one of the future challenges will be to optimize it through combination strategies with targeted therapies. The combination of anti-angiogenic and immunotherapy seems promising in gastric cancer.

Humanized CD19-directed CAR-T Cell Therapy in Pediatric Relapsed/Refractory Acute Lymphoblastic Leukemia With CNSL or Neurological Comorbidity

Chimeric antigen receptor T cell (CAR-T) therapy has breakthrough potential for relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL). However, because of the risk for neurotoxicity, trials usually exclude patients with central nervous system leukemia (CNSL) or active neurological comorbidities (NC). Here, we evaluated the efficacy and neurotoxicity of humanized CD19-directed CAR-T therapy for R/R ALL with CNSL or NC. Of 12 enrolled patients, 4 had CNSL with bone marrow (BM) or testicular recurrence, 3 had BM relapses with NC, and 5 had BM relapse without NC. Bridging chemotherapy was performed for high tumor burden before CAR-T therapy. Patients with CNSL or BM relapse with NC or without NC experienced 100% complete remission. Tumor burden reduction did not occur in 1 patient with NC, who developed grade 5 neurotoxicity before BM assessment, and one patient with CNSL developed leukoencephalopathy. Severe cytokine release syndrome and neurotoxicity developed in 0% with CNSL, 33.3% with BM relapse and NC, and 0% without NC. CAR-T cells expanded in the cerebrospinal fluid (CSF) of all patients with no difference among CNSL, BM with NC, or no NC (respective median percentages among lymphocyte: 33.7%, 48.2% and 34.5%, P =0.899; respective median concentrations: 0.82, 2.21, and 0.46/μL, P =0.719). Median CSF CAR-T cell duration was 5.5 (3-9) months with CNSL and 3 (2-3) months without CNSL ( P =0.031). CAR-T can be given safely and effectively to pediatric patients with R/R ALL with CNSL or NC who have near-normal neurological status. High tumor burden may confer increased risk for severe neurotoxicity.

Cytokine Release Syndrome after Chimeric Antigen Receptor Transduced T-Cell Therapy in Cancers: A Systematic Review

Patients with refractory or relapsed malignant disorders are in desperate condition, with few therapeutic options left, if any. Chimeric antigen receptor (CAR) transduced T-cell transplantation is a novel approach that has shown promising results as well as serious adverse events. This study aimed to systematically review the current data on the cytokine release syndrome (CRS) as a major side effect of CAR therapy. A systematic literature review was conducted to find reports of CAR T-cell therapy in the context of cancer patients and to extract reports of severe CRS. The factors that could significantly affect the incidence of CRS were investigated. Mortality rates were also compared regarding the occurrence of CRS. The incidence of severe CRS was 9.4% (95% confidence interval: 8.3-10.5) in the reviewed studies. Younger and older patients (vs. adults), higher doses of CAR T-cell infusions, lymphodepletion (LD) before CAR T-cell infusions, specific LD regimens, the source of allogeneic cells for the construction of CAR, chronic lymphocytic leukemia as the tumor type (vs. lymphoma), and CD28 as costimulatory domain in the structure of CAR were significantly associated with CRS events. Patients experiencing severe CRS had a significantly higher mortality rate within 2 and 3 months after transplantation. In conclusion, this study found many factors that could predict severe CRS and future clinical trials could reveal the relevance of appropriate interventions to the incidence and outcomes of CRS in cancer patients undergoing CAR T-cell transduced infusions.

Effect of granulocyte colony-stimulating factor on toxicities after CAR T cell therapy for lymphoma and myeloma

Chimeric antigen receptor T cells (CAR T) are groundbreaking therapies but may cause significant toxicities including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and cytopenias. Granulocyte colony-stimulating factor (G-CSF) is often used to mitigate neutropenia after CAR T, but there is no consensus recommended strategy due to hypothesized, but largely unknown risks of exacerbating toxicities. To investigate the impact of G-CSF, we retrospectively analyzed 197 patients treated with anti-CD19 CAR T for lymphoma and 47 patients treated with anti-BCMA CAR T for multiple myeloma. In lymphoma, 140 patients (71%) received prophylactic G-CSF before CAR T (mostly pegylated G-CSF) and were compared with 57 patients (29%) treated with G-CSF after CAR T or not exposed. Prophylactic G-CSF was associated with faster neutrophil recovery (3 vs. 4 days, P < 0.01) but did not reduce recurrent neutropenia later. Prophylactic G-CSF was associated with increased grade ≥2 CRS (HR 2.15, 95% CI 1.11-4.18, P = 0.02), but not ICANS. In multiple myeloma, prophylactic G-CSF was not used; patients were stratified by early G-CSF exposure (≤2 days vs. ≥3 days after CAR T or no exposure), with no significant difference in toxicities. Future trials should clarify the optimal G-CSF strategy to improve outcomes after CAR T.

The pathogenesis, diagnosis, prevention, and treatment of CAR-T cell therapy-related adverse reactions

Chimeric antigen receptor (CAR)-T cell therapy is effective in the treatment of refractory/relapsed (r/r) hematological malignancies (r/r B-cell lymphoblastic leukemia, B-cell lymphoma, and multiple myeloma). In addition, it is being explored as a treatment option for solid tumors. As of 31 March 2022, seven CAR-T therapies for hematological malignancies have been approved worldwide. Although CAR-T therapy is an effective treatment for many malignancies, it also causes adverse effects. The incidence of cytokine release syndrome (CRS), the most common adverse reaction after infusion of CAR-T cells, is as high as 93%.CRS, is the leading risk factor of immune effector cell-associated neurotoxicity syndrome (ICANS), as well as cardiovascular, hematological, hepatorenal, skin, pulmonary, and gastrointestinal toxicity. Severe adverse reactions complicated by CRS severely impede the widespread application of CAR-T therapy. The CAR-T product was initially approved in 2017; however, only limited studies have investigated the adverse reactions owing to CAR-T therapy compared to that of clinically approved drugs. Thus, we aimed to elucidate the mechanisms, risk factors, diagnostic criteria, and treatment of toxicities concurrent with CRS, thereby providing a valuable reference for the safe, effective, and widespread application of CAR-T therapy.

Chimeric Antigen Receptor (CAR) T-cell Treatment in Renal Cell Carcinoma: Current clinical trials and future directions

Renal cell carcinoma (RCC) has long been found to be responsive to immunotherapy. While high dose interleukin-2 resulted in some durable remissions, this treatment has largely been replaced by immune checkpoint inhibitor therapy, due to the safer toxicity profile and emerging evidence for long term remissions. However, the majority of patients continue to face disease progression and death from metastatic RCC. Chimeric antigen receptor T-cells (CAR T) represent the next step in immunotherapy for this malignancy and hold promise for a higher rate of durable remissions. The realization of this therapeutic strategy for RCC will require identification of the best tumor antigen and T cell modifications and will depend on achieving remissions with an acceptable toxicity profile. This review summarizes current CAR T-cell treatment targets and clinical trials for metastatic RCC, highlighting the potential therapeutic impact as well as obstacles to successful development.

Ciltacabtagene autoleucel: The second anti-BCMA CAR T-cell therapeutic armamentarium of relapsed or refractory multiple myeloma

Ciltacabtagene autoleucel (also known as cilta-cel) is a chimeric antigen receptor (CAR) T-cell therapy that targets B-cell maturation antigen (BCMA) on the surface of cancer cells in B cell malignancies, such as multiple myeloma (MM). It is a second-generation CAR that is outfitted with an ectodomain comprising two BCMA-binding single chain variable fragment (ScFv) domains, a transmembrane domain, and an endodomain possessing CD3ζ and 4-1BB. Cilta-cel is an autologous, gene-edited CAR T-cell that is prepared by collecting and modifying the recipient’s T-cells to create a patient personalized treatment in the laboratory to be infused back. This CAR T-cell product exceptionally entails CARs with two BCMA-targeting single-domain antibodies that detect two epitopes of BCMA expressed on the malignant cells of MM. Cilta-cel is the current addition to the treatment armamentarium of relapsed or refractory (r/r) MM after its approval by the FDA on February 28, 2022, based on the results of the Phase 1b/2 CARTITUDE-1 study. It was the second approved anti-BCMA CAR T-cell product after idecabtagene vicleucel (ide-cel) to treat myeloma patients. It induces early, deep, and long-lasting responses with a tolerable safety profile in r/r MM. Cilta-cel-treated myeloma patients may potentially experience adverse effects ranging from mild to life-threatening, but they are mostly manageable toxicities. Besides, it has a consistent safety profile upon a longer follow-up of patients. Cilta-cel generally outperforms ide cel in terms of efficacy in MM, but shows comparable adverse events. This review highlights the current updates on cilta-cel efficacy, adverse events, comparison with ide-cel, and its future direction in the treatment of MM.

Post-infusion CAR TReg cells identify patients resistant to CD19-CAR therapy

Approximately 60% of patients with large B cell lymphoma treated with chimeric antigen receptor (CAR) T cell therapies targeting CD19 experience disease progression, and neurotoxicity remains a challenge. Biomarkers associated with resistance and toxicity are limited. In this study, single-cell proteomic profiling of circulating CAR T cells in 32 patients treated with CD19-CAR identified that CD4+Helios+ CAR T cells on day 7 after infusion are associated with progressive disease and less severe neurotoxicity. Deep profiling demonstrated that this population is non-clonal and manifests hallmark features of T regulatory (TReg) cells. Validation cohort analysis upheld the link between higher CAR TReg cells with clinical progression and less severe neurotoxicity. A model combining expansion of this subset with lactate dehydrogenase levels, as a surrogate for tumor burden, was superior for predicting durable clinical response compared to models relying on each feature alone. These data credential CAR TReg cell expansion as a novel biomarker of response and toxicity after CAR T cell therapy and raise the prospect that this subset may regulate CAR T cell responses in humans.

Role of CD19 Chimeric Antigen Receptor T Cells in Second-Line Large B Cell Lymphoma: Lessons from Phase 3 Trials. An Expert Panel Opinion from the American Society for Transplantation and Cellular Therapy

Since 2017, 3 CD19-directed chimeric antigen receptor (CAR) T cell therapies-axicabtagene ciloleucel, tisagenlecleucel, and lisocabtagene maraleucel-have been approved for relapsed/refractory aggressive diffuse large B cell lymphoma after 2 lines of therapy. Recently, 3 prospective phase 3 randomized clinical trials were conducted to define the optimal second-line treatment by comparing each of the CAR T cell products to the current standard of care: ZUMA-7 for axicabtagene ciloleucel, BELINDA for tisagenlecleucel, and TRANSFORM for lisocabtagene maraleucel. These 3 studies, although largely addressing the same question, had different outcomes, with ZUMA-7 and TRANSFORM demonstrating significant improvement with CD19 CAR T cells in second-line therapy compared with standard of care but BELINDA not showing any benefit. The US Food and Drug Administration has now approved axicabtagene ciloleucel and lisocabtagene maraleucel for LBCL that is refractory to first-line chemoimmunotherapy or relapse occurring within 12 months of first-line chemoimmunotherapy. Following the reporting of these practice changing studies, here a group of experts convened by the American Society for Transplantation and Cellular Therapy provides a comprehensive review of the 3 studies, emphasizing potential differences, and shares perspectives on what these results mean to clinical practice in this new era of treatment of B cell lymphomas.

Comprehensive Serum Proteome Profiling of Cytokine Release Syndrome and Immune Effector Cell-Associated Neurotoxicity Syndrome Patients with B-Cell ALL Receiving CAR T19

PURPOSE

To study the biology and identify markers of severe cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) in children after chimeric antigen receptor T-cell (CAR T) treatment.

EXPERIMENTAL DESIGN

We used comprehensive proteomic profiling to measure over 1,400 serum proteins at multiple serial timepoints in a cohort of patients with B-cell acute lymphoblastic leukemia treated with the CD19-targeted CAR T CTL019 on two clinical trials.

RESULTS

We identified fms-like tyrosine kinase 3 (FLT3) and mast cell immunoglobulin-like receptor 1 (MILR1) as preinfusion predictive biomarkers of severe CRS. We demonstrated that CRS is an IFNγ-driven process with a protein signature overlapping with hemophagocytic lymphohistiocytosis (HLH). We identified IL18 as a potentially targetable cytokine associated with the development of ICANS.

CONCLUSIONS

We identified preinfusion biomarkers that can be used to predict severe CRS with a sensitivity, specificity, and accuracy superior to the current gold standard of disease burden. We demonstrated the fundamental role of the IFNγ pathway in driving CRS, suggesting CRS and carHLH are overlapping rather than distinct phenomena, an observation with important treatment implications. We identified IL18 as a possible targetable cytokine in ICANS, providing rationale for IL18 blocking therapies to be translated into clinical trials in ICANS.

Investigation of the risk factors to predict cytokine release syndrome in relapsed or refractory B-cell acute lymphoblastic leukemia patients receiving IL-6 knocking down anti-CD19 chimeric antigen receptor T-cell therapy

CD19 chimeric antigen receptor-T (CAR-T) cell therapy has achieved remarkable results in patients with relapsed or refractory B-cell acute lymphoblastic leukemia (r/r B-ALL). However, the cytokine release syndrome (CRS) was presented in most patients as common toxicity and severe CRS (sCRS) characterized by the sharp increase in interleukin-6 (IL-6) could be life-threatening. We conducted a phase II clinical trial of ssCAR-T-19 cells, anti-CD19 CAR-T cells with shRNA targeting IL-6, in 61 patients with r/r B-ALL. This trial was registered at www.clinicaltrials.gov as #NCT03275493. Fifty-two patients achieved CR while nine patients were considered NR. The median duration of response (DOR) and overall survival (OS) were not reached (>50 months). CRS developed in 81.97% of patients, including 54.10% with grades 1 to 2 (grade 1, 31.15%; grade 2, 22.95%) and 27.87% with grades 3 to 4 (grade 3, 26.23%; grade 4, 1.64%). sCRS occurs earlier than mild CRS (mCRS). A multivariable analysis of baseline characteristics identified high bone marrow disease burden and poor genetic risk before infusion as independent risk factors for sCRS. After infusion, patients with sCRS exhibited larger expansion of ssCAR-T-19 cells, higher peak levels of IL-6, IL-10, and IFN-γ, and suffered more severe hematological and non-hematological toxicities compared with those with mCRS.

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

Chimeric antigen receptor (CAR)-T cell therapy is an emerging staple in the treatment of certain hematological malignancies. While CAR-T cells have produced robust responses in certain hematological malignancies, toxicities associated with the therapy have limited their use. Immune Effector Cell Associated Neurotoxicity Syndrome (ICANS) is a potentially life-threatening neurotoxicity that commonly occurs with CAR-T cell therapy. Here we will discuss ICANS, its treatment, possible mechanisms, and potential solutions to this critical limitation of CAR-T cell therapy. As the field of CAR-T cell therapy evolves, improved treatments and methods to circumvent or overcome ICANS are necessary to improve morbidity, mortality, and decrease the cost of CAR-T cell therapy. This serious, life-threatening side effect needs to be studied to better understand its mechanisms and develop treatments and alternative strategies.

Secretory co-factors in next-generation cellular therapies for cancer

Since chimeric antigen receptor (CAR) T-cell therapies for hematologic malignancies were approved by the U.S. Food and Drug Administration, numerous "next-generation" CAR T cells have been developed to improve their safety, efficacy, and applicability. Although some of these novel therapeutic strategies are promising, it remains difficult to apply these therapies to solid tumors and to control adverse effects, such as cytokine release syndrome and neurotoxicity. CAR T cells are generated using highly scalable genetic engineering techniques. One of the major strategies for producing next-generation CAR T cells involves the integration of useful co-factor(s) into the artificial genetic design of the CAR gene, resulting in next-generation CAR T cells that express both CAR and the co-factor(s). Many soluble co-factors have been reported for CAR T cells and their therapeutic effects and toxicity have been tested by systemic injection; therefore, CAR T cells harnessing secretory co-factors could be close to clinical application. Here, we review the various secretory co-factors that have been reported to improve the therapeutic efficacy of CAR T cells and ameliorate adverse events. In addition, we discuss the different co-factor expression systems that have been used to optimize their beneficial effects. Altogether, we demonstrate that combining CAR T cells with secretory co-factors will lead to next-generation CAR T-cell therapies that can be used against broader types of cancers and might provide advanced tools for more complicated synthetic immunotherapies.

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.

Understanding CAR T cell-tumor interactions: Paving the way for successful clinical outcomes

Since their approval 5 years ago, chimeric antigen receptor (CAR) T cells have gained great importance in the daily clinical practice and treatment of hematological malignancies, although many challenges to their use remain, such as limited long-term CAR T cell efficacy due to disease resistance or recurrence. After a brief overview of CAR T cells, their approval, therapeutic successes, and ongoing limitations, this review discusses what is known about CAR T cell activation, their expansion and persistence, their mechanisms of cytotoxicity, and how the CAR design and/or tumor-intrinsic factors influence these functions. This review also examines the role of cytokines in CAR T cell-associated toxicity and their effects on CAR T cell function. Furthermore, we discuss several resistance mechanisms, including obstacles associated with CAR treatment of solid tumors. Finally, we provide a future outlook on next-generation strategies to further optimize CARs and improve clinical outcomes.

CAR T-Based Therapies in Lymphoma: A Review of Current Practice and Perspectives

While more than half of non-Hodgkin lymphomas (NHL) can be cured with modern frontline chemoimmunotherapy regimens, outcomes of relapsed and/or refractory (r/r) disease in subsequent lines remain poor, particularly if considered ineligible for hematopoietic stem cell transplantation. Hence, r/r NHLs represent a population with a high unmet medical need. This therapeutic gap has been partially filled by adoptive immunotherapy. CD19-directed autologous chimeric antigen receptor (auto-CAR) T cells have been transformative in the treatment of patients with r/r B cell malignancies. Remarkable response rates and prolonged remissions have been achieved in this setting, leading to regulatory approval from the U.S. Food and Drug Administration (FDA) of four CAR T cell products between 2017 and 2021. This unprecedented success has created considerable enthusiasm worldwide, and autologous CAR T cells are now being moved into earlier lines of therapy in large B cell lymphoma. Herein, we summarize the current practice and the latest progress of CD19 auto-CAR T cell therapy and the management of specific toxicities and discuss the place of allogeneic CAR T development in this setting.

Molecular monitoring of T-cell kinetics and migration in severe neurotoxicity after real-world CD19-specific chimeric antigen receptor T cell therapy

CD19-specific chimeric antigen receptor (CD19-CAR) T-cell therapies mediate durable responses in late-stage B-cell malignancies, but can be complicated by a potentially severe immune effector cell-associated neurotoxicity syndrome (ICANS). Despite broad efforts, the precise mechanisms of ICANS are not entirely known, and resistance to current ICANSdirected therapies (especially corticosteroids) has been observed. Recent data suggest that inflammatory cytokines and/or targeting of cerebral CD19-expressing pericytes can disrupt the blood-brain barrier and facilitate influx of immune cells, including CAR T cells. However, specific tools for CD19-CAR T-cell analysis within often minute samples of cerebrospinal fluid (CSF) are not broadly available. Here, we applied our recently developed digital polymerase chain reaction assays to monitor CD19-CAR T-cell kinetics in CSF and blood in real-world patients with neurotoxicity. Consistently, we observed a CAR T-cell enrichment within CSF in ICANS patients with further progressive accumulation despite intense corticosteroid- containing immuno-chemotherapies in a subset of patients with prolonged and therapy-resistant grade 3-4 neurotoxicity. We used next-generation T-cell receptor-b sequencing to assess the repertoire of treatment-refractory cells. Longitudinal analysis revealed a profound skewing of the T-cell receptor repertoire, which at least partly reflected selective expansion of infused T-cell clones. Interestingly, a major fraction of eventually dominating hyperexpanded T-cell clones were of non-CAR T-cell derivation. These findings hint to a role of therapy-refractory T-cell clones in severe ICANS development and prompt future systematic research to determine if CAR T cells may serve as 'door openers' and to further characterize both CAR-positive and non-CAR T cells to interrogate the transcriptional signature of these possibly pathologic T cells.

The role of neurologists in the era of cancer immunotherapy: Focus on CAR T-cell therapy and immune checkpoint inhibitors

Cancer immunotherapy represents a novel anticancer strategy that acts directly on the immune system, promoting its activation toward cancer cells to enhance its natural ability to fight cancer. Among various treatments currently used or investigated, chimeric antigen receptors (CAR) T-cell therapy and immune checkpoint inhibitors (ICIs) have consistently proven their efficacy. These innovations are progressively improving the standard of care in cancer treatment, yet they are hampered by novel neurological adverse events, attributing to neurologists a key role in the multidisciplinary oncological team. Indeed, neurotoxicity may develop in up to 77% of patients who received CAR T-cell therapy and usually presents with encephalopathy characterized by a predominant frontal lobe dysfunction. This neurotoxicity is related to cytokine release syndrome, a systemic hyperinflammatory condition triggered by CAR T-cells. On the other hand, following treatment with ICIs, unrestrained T-cells may lead to central and peripheral neurological disorders by antigen-directed autoimmunity. Notably, biological and clinical similarities have been underlined between neurotoxicity related to CAR T-cell therapy and neurological manifestations of cytokine storms (e.g. COVID-19-related encephalopathy), as well as between a subgroup of ICI-related neurological adverse events and paraneoplastic neurological syndromes. Therefore, these cancer immunotherapy-related neurological syndromes may provide an unprecedented, perhaps transitory, opportunity to shed light on the underlying pathogenic mechanisms of a wide spectrum of neurological syndromes and to push forward our knowledge in neuroimmunology.

Toxicity management strategies for next-generation novel therapeutics in multiple myeloma

The therapeutic options available for patients with multiple myeloma have greatly expanded over the past decade and incorporating these novel agents into routine clinical practice has significantly improved outcomes. The next generation of therapeutics is available for relapsed and refractory patients either as standard of care or in clinical trial, and these drugs represent a generational paradigm shift. Patients now have access to a multitude of novel immunotherapeutics, including monoclonal antibodies, an antibody-drug conjugate, chimeric antigen receptor T-cells (CAR-T), and bispecific T-cell redirecting antibodies, and novel oral therapies including selinexor (selective inhibitor of nuclear export) and venetoclax (bcl-2 inhibitor). While these drugs have the potential to be highly efficacious in certain subsets of patients when used as single agents or in combination regimens, they are each associated with unique toxicity profiles. It is imperative to understand these potential adverse events to ensure patient safety. Appropriate supportive care management is paramount to maximize drug exposure and therapeutic efficacy. The following review focuses its discussion on drugs and combination regimens that are currently FDA-approved and those that continue to be investigated in clinical trials, highlights the clinically relevant toxicity profiles for each of the different agents, and provides practical considerations for the treatment team.

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.

Clinical trials for chimeric antigen receptor T-cell therapy: lessons learned and future directions

PURPOSE OF REVIEW

The purpose of this review is to summarize the status and utilization of chimeric antigen receptor T-cell (CAR-T) therapy based on the most recent clinical trials in patients with leukemia and lymphoma. Additionally, this review will highlight limitations in current strategies, discuss efforts in toxicity mitigation, and outline future directions for investigation.

RECENT FINDINGS

CD19 targeted CAR-T-cell therapy (CD19-CAR) is highly effective in patients with relapsed/refractory (r/r) B-cell hematologic malignancies. However, multiple challenges have arisen, particularly life-threatening adverse events, such as cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome. Despite these challenges, recent CD19-CAR trials, including two randomized studies, have demonstrated both impressive initial results along with durable responses. Combined with results emerging from 'real-world' experience, the efficacy of CAR-T-cells is high, propelling CAR-T-cells studies targeting alternate B-cell antigens [e.g. CD20, CD22 and CD269 (BCMA)] and other targets for hematologic malignancies, along with solid and CNS tumors.

SUMMARY

Given the benefit for CD19-CAR, determining the appropriate place in utilization for both an individual patient's treatment course and more broadly in the generalized treatment paradigm is critically needed. We discuss the most recent trials exploring this topic and future directions in the field.