Immune Effector Cell-Associated Hemophagocytic Lymphohistiocytosis-Like Syndrome

CD22-directed CAR T-cell therapy for large B-cell lymphomas progressing after CD19-directed CAR T-cell therapy: a dose-finding phase 1 study

BACKGROUND

Outcomes are poor for patients with large B-cell lymphoma who relapse after CD19-directed chimeric antigen receptor (CAR) T-cell therapy (CAR19). CD22 is a nearly universally expressed B-cell surface antigen and the efficacy of a CD22-directed CAR T-cell therapy (CAR22) in large B-cell lymphoma is unknown, which was what we aimed to examine in this study.

METHODS

In this single centre, open-label, dose-escalation phase 1 trial, we intravenously administered CAR22 at two dose levels (1 million and 3 million CAR22-positive T cells per kg of bodyweight) to adult patients (aged ≥18 years) who relapsed after CAR19 or had CD19-negative large B-cell lymphoma. The primary endpoints were manufacturing feasibility, safety measured by the incidence and severity of adverse events and dose-limiting toxicities, and identification of the maximum tolerated dose (ie, the recommended phase 2 dose). This study is registered with ClinicalTrials.gov (NCT04088890) and is active, but closed for enrolment.

FINDINGS

From Oct 17, 2019, to Oct 19, 2022, a total of 41 patients were assessed for eligibility; however, one patient withdrew. 40 patients underwent leukapheresis and 38 (95%) had CAR T-cell products manufactured successfully. The median age was 65 years (range 25-84), 17 (45%) were women, 32 (84%) had elevated pretreatment lactate dehydrogenase, 11 (29%) had refractory disease to all previous therapies, and patients had received a median of four lines of previous therapy (range 3-8). Of the 38 patients treated, 37 (97%) had relapsed after previous CAR19. The identified maximum tolerated dose was 1 million CAR T cells per kg. Of 29 patients who received the maximum tolerated dose, no patients developed a dose-limiting toxicity or grade 3 or higher cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, or immune effector cell-associated haemophagocytic lymphohistiocytosis-like syndrome.

INTERPRETATION

This trial identifies CD22 as an immunotherapeutic target in large B-cell lymphoma and demonstrates the durable clinical activity of CAR22 in patients with disease progression after CAR19 therapy. Although these findings are promising, it is essential to recognise that this is a phase 1 dose-finding study. Further investigations are warranted to establish the long-term efficacy and to delineate the patient subgroups that will derive the most benefit from this therapeutic approach.

FUNDING

National Cancer Institute, National Institutes of Health, Stanford Cancer Institute, Leukemia & Lymphoma Society, Parker Institute for Cancer Immunotherapy, Lymph & Co, and the European Hematology Association.

A research center's experience of T-cell-redirecting therapies in triple-class refractory multiple myeloma

ABSTRACT

The efficacies of chimeric antigen receptor T cells (CAR-Ts) and bispecific monoclonal antibodies (BiAbs) for triple-class refractory (TCR) myeloma have not previously been compared, and clinical data on how to rescue patients after relapse from these immunotherapies are limited. A retrospective study of 73 TCR patients included in trials was conducted: 36 received CAR-Ts and 37 received BiAbs. CAR-Ts produced a higher overall response rate (ORR) than BiAbs (97.1% vs 56.8%, P = .002). After a median of follow-up of 18.7 months, no significant difference in progression-free survival (PFS) was observed between the CAR-T and BiAbs groups (16.6 vs 10.8 months; P = .090), whereas overall survival (OS) was significantly longer in the CAR-T than in the BiAbs group (49.2 vs 22.6 months; P = .021). BiAbs after CAR-Ts yielded a higher ORR and longer PFS2 than did nonredirecting T-cell therapies after CAR-Ts (ORR: 87.5% vs 50.0%; PFS2: 22.9 vs 12.4 months). By contrast, BiAbs after BiAbs resulted in an ORR of 33% and PFS2 of 8.4 months, which was similar to that produced by the nonredirecting T-cell therapies (ORR: 28.6%; PFS2: 8.1 months). Although this is a pooled analysis of different trials with different products and the patient profile is different for CAR-Ts and BiAbs, both were effective therapies for TCR myeloma. However, in our experience, although the PFS was similar with the 2 approaches, CAR-T therapy resulted in better OS, mainly because of the efficacy of BiAbs as rescue therapy. Our results highlight the importance of treatment sequence in real-word experience.

A systematic review and meta-analysis of nonrelapse mortality after CAR T cell therapy

Although chimeric antigen receptor (CAR) T cell therapy represents a transformative immunotherapy, it is also associated with distinct toxicities that contribute to morbidity and mortality. In this systematic review and meta-analysis, we searched MEDLINE, Embase and CINAHL (Cochrane) for reports of nonrelapse mortality (NRM) after CAR T cell therapy in lymphoma and multiple myeloma up to March 2024. After extraction of causes and numbers of death, we analyzed NRM point estimates using random-effect models. We identified 7,604 patients across 18 clinical trials and 28 real-world studies. NRM point estimates varied across disease entities and were highest in patients with mantle-cell lymphoma (10.6%), followed by multiple myeloma (8.0%), large B cell lymphoma (6.1%) and indolent lymphoma (5.7%). Entity-specific meta-regression models for large B cell lymphoma and multiple myeloma revealed that axicabtagene ciloleucel and ciltacabtagene autoleucel were independently associated with increased NRM point estimates, respectively. Of 574 reported nonrelapse deaths, over half were attributed to infections (50.9%), followed by other malignancies (7.8%) and cardiovascular/respiratory events (7.3%). Conversely, the CAR T cell-specific side effects, immune effector cell-associated neurotoxicity syndrome/neurotoxicity, cytokine release syndrome and hemophagocytic lymphohistiocytosis, represented only a minority of nonrelapse deaths (cumulatively 11.5%). Our findings underline the critical importance of infectious complications after CAR T cell therapy and support the comprehensive reporting of NRM, including specific causes and long-term outcomes.

Diagnostic pitfalls in assessment of ferritin following CAR-T-cell therapy: Understanding the hook effect

The hook effect is a well-described but clinically underappreciated immunoassay interference, where a falsely lowered result is caused by analyte excess. We describe a situation in which ferritin immunoassay results from a 27-year-old female with immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome were more than 1000 times lower at a reference laboratory than those determined in-house after dilution. This case underscores the importance for clinical care providers to be aware of the impact of the hook effect on ferritin measurements, and to promptly communicate with the laboratory when there are discrepancies between clinical symptoms and test results.

Current understanding and management of CAR T cell-associated toxicities

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of several haematological malignancies and is being investigated in patients with various solid tumours. Characteristic CAR T cell-associated toxicities such as cytokine-release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are now well-recognized, and improved supportive care and management with immunosuppressive agents has made CAR T cell therapy safer and more feasible than it was when the first regulatory approvals of such treatments were granted in 2017. The increasing clinical experience with these therapies has also improved recognition of previously less well-defined toxicities, including movement disorders, immune effector cell-associated haematotoxicity (ICAHT) and immune effector cell-associated haemophagocytic lymphohistiocytosis-like syndrome (IEC-HS), as well as the substantial risk of infection in patients with persistent CAR T cell-induced B cell aplasia and hypogammaglobulinaemia. A more diverse selection of immunosuppressive and supportive-care pharmacotherapies is now being utilized for toxicity management, yet no universal algorithm for their application exists. As CAR T cell products targeting new antigens are developed, additional toxicities involving damage to non-malignant tissues expressing the target antigen are a potential hurdle. Continued prospective evaluation of toxicity management strategies and the design of less-toxic CAR T cell products are both crucial for ongoing success in this field. In this Review, we discuss the evolving understanding and clinical management of CAR T cell-associated toxicities.

Overcoming the challenges of primary resistance and relapse after CAR-T cell therapy

INTRODUCTION

While CAR T-cell therapy has led to remarkable responses in relapsed B-cell hematologic malignancies, only 50% of patients ultimately have a complete, sustained response. Understanding the mechanisms of resistance and relapse after CAR T-cell therapy is crucial to future development and improving outcomes.

AREAS COVERED

We review reasons for both primary resistance and relapse after CAR T-cell therapies. Reasons for primary failure include CAR T-cell manufacturing problems, suboptimal fitness of autologous T-cells themselves, and intrinsic features of the underlying cancer and tumor microenvironment. Relapse after initial response to CAR T-cell therapy may be antigen-positive, due to CAR T-cell exhaustion or limited persistence, or antigen-negative, due to antigen-modulation on the target cells. Finally, we discuss ongoing efforts to overcome resistance to CAR T-cell therapy with enhanced CAR constructs, manufacturing methods, alternate cell types, combinatorial strategies, and optimization of both pre-infusion conditioning regimens and post-infusion consolidative strategies.

EXPERT OPINION

There is a continued need for novel approaches to CAR T-cell therapy for both hematologic and solid malignancies to obtain sustained remissions. Opportunities for improvement include development of new targets, optimally combining existing CAR T-cell therapies, and defining the role for adjunctive immune modulators and stem cell transplant in enhancing long-term survival.

Marked hyperferritinemia in critically ill cancer patients

OBJECTIVES

To investigate characteristics and outcomes of critically ill cancer patients with marked hyperferritinemia.

METHODS

A single-center retrospective analysis comprising cancer patients with a ferritin level >10.000 μg/L treated in the intensive care unit (ICU) between 2012 and 2022 was conducted.

RESULTS

A total of 117 patients were included in the analysis. The median age was 59 years (range: 15-86 years). Females accounted for 48% of cases. 90% of patients had a hematologic malignancy. The median maximum ferritin level was 27.349 μg/L (range: 10.300-426.073 μg/L). The diagnostic criteria of septic shock were fulfilled in 51% of cases; 31% of patients had hemophagocytic lymphohistiocytosis (HLH) according to the HLH-2004 criteria. Mechanical ventilation, renal replacement therapy and the use of vasopressors were necessary in 59%, 35% and 70% of cases, respectively. The ICU, hospital, 90-day and 1-year survival rates were 33.3%, 23.1%, 23.7% and 11.7%. Patients with septic shock had a worse survival than those without septic shock (p = .001); the survival of patients who fulfilled the HLH-2004 criteria did not differ from those who did not (p = .88).

CONCLUSION

Critically ill cancer patients with marked hyperferritinemia have poor outcomes. The present data may help to make informed decisions for this patient group.

CAR19 monitoring by peripheral blood immunophenotyping reveals histology-specific expansion and toxicity

ABSTRACT

Chimeric antigen receptor (CAR) T cells directed against CD19 (CAR19) are a revolutionary treatment for B-cell lymphomas (BCLs). CAR19 cell expansion is necessary for CAR19 function but is also associated with toxicity. To define the impact of CAR19 expansion on patient outcomes, we prospectively followed a cohort of 236 patients treated with CAR19 (brexucabtagene autoleucel or axicabtagene ciloleucel) for mantle cell lymphoma (MCL), follicular lymphoma, and large BCL (LBCL) over the course of 5 years and obtained CAR19 expansion data using peripheral blood immunophenotyping for 188 of these patients. CAR19 expansion was higher in patients with MCL than other lymphoma histologic subtypes. Notably, patients with MCL had increased toxicity and required fourfold higher cumulative steroid doses than patients with LBCL. CAR19 expansion was associated with the development of cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, and the requirement for granulocyte colony-stimulating factor 14 days after infusion. Younger patients and those with elevated lactate dehydrogenase (LDH) had significantly higher CAR19 expansion. In general, no association between CAR19 expansion and LBCL treatment response was observed. However, when controlling for tumor burden, we found that lower CAR19 expansion in conjunction with low LDH was associated with improved outcomes in LBCL. In sum, this study finds CAR19 expansion principally associates with CAR-related toxicity. Additionally, CAR19 expansion as measured by peripheral blood immunophenotyping may be dispensable to favorable outcomes in LBCL.

The Challenging Approach to Multiple Myeloma: From Disease Diagnosis and Monitoring to Complications Management

The outcome of multiple myeloma (MM) has significantly improved in the last few decades due to several factors such as new biological discoveries allowing to better stratify disease risk, development of more effective therapies and better management of side effects related to them. However, handling all these aspects requires an interdisciplinary approach involving multiple knowledge and collaboration of different specialists. The hematologist, faced with a patient with MM, must not only choose a treatment according to patient and disease characteristics but must also know when therapy needs to be started and how to monitor it during and after treatment. Moreover, he must deal not only with organ issues related to MM such as bone disease, renal failure or neurological disease but also with adverse events, often very serious, related to novel therapies, particularly new generation immunotherapies such as CAR T cell therapy and bispecific antibodies. In this review, we provide an overview on the newer MM diagnostic and monitoring strategies and on the main side effects of MM therapies, focusing on adverse events occurring during treatment with CAR T cells and bispecific antibodies.

Practical Aspects of Immunotherapy: A Report from the 20th International Myeloma Society (IMS) Annual Meeting

Immunotherapeutic strategies, specifically T-cell-redirected therapies, have been transformative in the context of multiple myeloma (MM). With the approval of two chimeric antigen receptor T-cell (CAR-T) drug products and three bispecific antibodies/T-cell engagers (bsAbs/TCEs) in relapsed/refractory MM (RRMM), the 20th annual IMS meeting dedicated a session to the practical aspects of these therapies. Here, we highlight the discussion during this session, including the role of CAR-T and bsAb therapies in frontline MM treatment, management of acute toxicities, prevention and management of infections, and finally treatment sequencing of T-cell redirected therapies.

The Burden of Invasive Fungal Disease Following Chimeric Antigen Receptor T-Cell Therapy and Strategies for Prevention

Chimeric antigen receptor (CAR) T-cell therapy is a novel immunotherapy approved for the treatment of hematologic malignancies. This therapy leads to a variety of immunologic deficits that could place patients at risk for invasive fungal disease (IFD). Studies assessing IFD in this setting are limited by inconsistent definitions and heterogeneity in prophylaxis use, although the incidence of IFD after CAR T-cell therapy, particularly for lymphoma and myeloma, appears to be low. This review evaluates the incidence of IFD after CAR T-cell therapy, and discusses optimal approaches to prevention, highlighting areas that require further study as well as future applications of cellular therapy that may impact IFD risk. As the use of CAR T-cell therapy continues to expand for hematologic malignancies, solid tumors, and most recently to include non-oncologic diseases, understanding the risk for IFD in this uniquely immunosuppressed population is imperative to prevent morbidity and mortality.

Immune effector cell-associated haematotoxicity after CAR T-cell therapy: from mechanism to management

Genetically engineered chimeric antigen receptor (CAR) T cells have become an effective treatment option for several advanced B-cell malignancies. Haematological side-effects, classified in 2023 as immune effector cell-associated haematotoxicity (ICAHT), are very common and can predispose for clinically relevant infections. As haematopoietic reconstitution after CAR T-cell therapy differs from chemotherapy-associated myelosuppression, a novel classification system for early and late ICAHT has been introduced. Furthermore, a risk stratification score named CAR-HEMATOTOX has been developed to identify candidates at high risk of ICAHT, thereby enabling risk-based interventional strategies. Therapeutically, growth factor support with granulocyte colony-stimulating factor (G-CSF) is the mainstay of treatment, with haematopoietic stem cell (HSC) boosts available for patients who are refractory to G-CSF (if available). Although the underlying pathophysiology remains poorly understood, translational studies from the past 3 years suggest that CAR T-cell-induced inflammation and baseline haematopoietic function are key contributors to prolonged cytopenia. In this Review, we provide an overview of the spectrum of haematological toxicities after CAR T-cell therapy and offer perspectives on future translational and clinical developments.

Consensus guidelines and recommendations for the management and response assessment of chimeric antigen receptor T-cell therapy in clinical practice for relapsed and refractory multiple myeloma: a report from the International Myeloma Working Group Immunotherapy Committee

Chimeric antigen receptor (CAR) T-cell therapy has shown promise in patients with late-line refractory multiple myeloma, with response rates ranging from 73 to 98%. To date, three products have been approved: Idecabtagene vicleucel (ide-cel) and ciltacabtagene autoleucel (cilta-cel), which are approved by the US Food and Drug Administration, the European Medicines Agency, Health Canada (ide-cel only), and Brazil ANVISA (cilta-cel only); and equecabtagene autoleucel (eque-cel), which was approved by the Chinese National Medical Products Administration. CAR T-cell therapy is different from previous anti-myeloma therapeutics with unique toxic effects that require distinct mitigation strategies. Thus, a panel of experts from the International Myeloma Working Group was assembled to provide guidance for clinical use of CAR T-cell therapy in myeloma. This consensus opinion is from experts in the field of haematopoietic cell transplantation, cell therapy, and multiple myeloma therapeutics.

Mechanisms and management of CAR T toxicity

Chimeric antigen receptor (CAR) T cell therapies have dramatically improved treatment outcomes for patients with relapsed or refractory B-cell acute lymphoblastic leukemia, large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, and multiple myeloma. Despite unprecedented efficacy, treatment with CAR T cell therapies can cause a multitude of adverse effects which require monitoring and management at specialized centers and contribute to morbidity and non-relapse mortality. Such toxicities include cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, neurotoxicity distinct from ICANS, immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome, and immune effector cell-associated hematotoxicity that can lead to prolonged cytopenias and infectious complications. This review will discuss the current understanding of the underlying pathophysiologic mechanisms and provide guidelines for the grading and management of such toxicities.

International Myeloma Working Group immunotherapy committee consensus guidelines and recommendations for optimal use of T-cell-engaging bispecific antibodies in multiple myeloma

Multiple myeloma remains an incurable disease, despite the development of numerous drug classes and combinations that have contributed to improved overall survival. Immunotherapies directed against cancer cell-surface antigens, such as chimeric antigen receptor (CAR) T-cell therapy and T-cell-redirecting bispecific antibodies, have recently received regulatory approvals and shown unprecedented efficacy. However, these immunotherapies have unique mechanisms of action and toxicities that are different to previous treatments for myeloma, so experiences from clinical trials and early access programmes are essential for providing specific recommendations for management of patients, especially as these agents become available across many parts of the world. Here, we provide expert consensus clinical practice guidelines for the use of bispecific antibodies for the treatment of myeloma. The International Myeloma Working Group is also involved in the collection of prospective real-time data of patients treated with such immunotherapies, with the aim of learning continuously and adapting clinical practices to optimise the management of patients receiving immunotherapies.

Current Challenges in Chimeric Antigen Receptor T-cell Therapy in Patients With B-cell Lymphoid Malignancies

Chimeric antigen receptor (CAR) T-cell therapy is a promising immunotherapy based on genetically engineered T cells derived from patients. The introduction of CAR T-cell therapy has changed the treatment paradigm of patients with B-cell lymphoid malignancies. However, challenging issues including managing life-threatening toxicities related to CAR T-cell infusion and resistance to CAR T-cell therapy, leading to progression or relapse, remain. This review summarizes the issues with currently approved CAR T-cell therapies for patients with relapsed or refractory B-cell lymphoid malignancies, including lymphoma and myeloma. We focus on unique toxicities after CAR T-cell therapy, such as cytokine-related events and hematological toxicities, and the mechanisms underlying post-CAR T-cell failure.

Optimizing the CAR T-Cell Therapy Experience in Multiple Myeloma: Clinical Pearls From an Expert Roundtable

Chimeric antigen receptor T-cell (CAR-T) therapies offer substantial advancement in the treatment of multiple myeloma (MM). However, the CAR-T therapy process involves complex decision-making that is informed by many variables. This review aims to provide an overview of the patient selection and administration process for CAR-T therapy for MM from the perspective of experienced healthcare providers (HCPs), including considerations for each step in the CAR-T therapy process. Referring HCPs should initiate conversations with HCPs at CAR-T capable centers earlier in the treatment journey, even before patients are eligible for CAR-T therapy, particularly for patients from underserved populations and patients with high-risk disease, to ensure adequate time for logistical planning and patient education. Patient selection for CAR-T therapy may be guided by factors such as performance status, rate of disease progression, and logistical considerations. Some anticancer therapies may affect T-cell fitness and therefore impact CAR-T manufacturing and patient outcomes; however, additional research is needed to confirm this in MM. Bridging therapies should be tailored to the needs of the patient and ideally halted 1 week or longer before CAR-T infusion, contingent upon the agent(s) used. Lymphodepletion regimens may need to be modified for patients with renal insufficiency. Collaboration with HCPs at both the treating and referring centers is important to optimize coordinated care of patients. Collaboration with and guidance from experienced HCPs throughout patient selection, referral, and CAR-T administration is instrumental in optimizing patient outcomes as access to CAR-T therapies expands.

CD22 CAR T cells demonstrate high response rates and safety in pediatric and adult B-ALL: Phase 1b results

Chimeric antigen receptor (CAR) T cells targeting CD22 (CD22-CAR) provide a therapeutic option for patients with CD22+ malignancies with progression after CD19-directed therapies. Using on-site, automated, closed-loop manufacturing, we conducted parallel Phase 1b clinical trials investigating a humanized CD22-CAR with 41BB costimulatory domain in children and adults with heavily treated, relapsed/refractory (r/r) B-ALL. Of 19 patients enrolled, 18 had successful CD22-CAR manufacturing, and 16 patients were infused. High grade (3-4) cytokine release syndrome (CRS) and immune effector-cell-associated neurotoxicity syndrome (ICANS) each occurred in only one patient; however, three patients experienced immune-effector-cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS). Twelve of 16 patients (75%) achieved CR with an overall 56% MRD-negative CR rate. Duration of response was overall limited (median 77 days), and CD22 expression was downregulated in 4/12 (33%) available samples at relapse. In summary, we demonstrate that closed-loop manufacturing of CD22-CAR T cells is feasible and is associated with a favorable safety profile and high CR rates in pediatric and adult r/r B-ALL, a cohort with limited CD22-CAR reporting.

Development of a Safety Surveillance Plan for the Academic Medicine Sponsor Performing First-in-Human Cellular Therapy Clinical Trials: A Report from the Consortium for Pediatric Cellular Immunotherapy

Pharmacovigilance (PV), also known as drug safety, is the science of risk management involving the detection, assessment, understanding, and prevention of adverse effects related to a medication. This discipline has traditionally focused on the postmarketing period, with less attention to early-phase clinical trials. However, during the immunotherapy and cellular therapy investigational stage, regulatory agencies are increasingly emphasizing the need to identify and characterize safety signals earlier in clinical development as part of a comprehensive safety surveillance plan. Compliance with PV and safety regulations are further heightened as cell and gene therapy (CGT) trials grow in complexity and scope owing to ever-changing and increasingly rigorous regulatory mandates. Based on this changing landscape, a critical aspect of early-phase trials of cellular products where significant safety events are anticipated is to ensure that every effort is made to protect clinical trial participants by maximizing attention to the risk-versus-benefit profile. This includes the development of robust plans for safety surveillance that provide a continual assessment of safety signals to enable safety reporting to regulatory bodies and the Food and Drug Administration, a regular analysis of aggregate safety data, and a plan to communicate safety findings. This report focuses on PV in early-phase clinical trials of first-in-human investigational products sponsored by academic centers in which the availability of PV resources and subject matter experts is limited. To more fully understand the challenges of CGT PV oversight within pediatric academic medical centers conducting early-phase clinical trials, a working group from institutions participating in the Consortium for Pediatric Cellular Immunotherapy composed of faculty and regulatory professionals was convened to compare experiences, identify best practices, and review published literature to identify commonalities and opportunities for alignment. Here we present guidelines on PV planning in early-phase CGT clinical trials occurring in academic medical centers and offer strategies to mitigate risk to trial participants. Standards to address regulatory requirements and governance for safety signal identification and risk assessment are discussed.

Heterogeneity of macrophage activation syndrome and treatment progression

Macrophage activation syndrome (MAS) is a rare complication of autoimmune inflammatory rheumatic diseases (AIIRD) characterized by a progressive and life-threatening condition with features including cytokine storm and hemophagocytosis. Predisposing factors are typically associated with microbial infections, genetic factors (distinct from typical genetically related hemophagocytic lymphohistiocytosis (HLH)), and inappropriate immune system overactivation. Clinical features include unremitting fever, generalized rash, hepatosplenomegaly, lymphadenopathy, anemia, worsening liver function, and neurological involvement. MAS can occur in various AIIRDs, including but not limited to systemic juvenile idiopathic arthritis (sJIA), adult-onset Still's disease (AOSD), systemic lupus erythematosus (SLE), Kawasaki disease (KD), juvenile dermatomyositis (JDM), rheumatoid arthritis (RA), and Sjögren's syndrome (SS), etc. Although progress has been made in understanding the pathogenesis and treatment of MAS, it is important to recognize the differences between different diseases and the various treatment options available. This article summarizes the cell types and cytokines involved in MAS-related diseases, the heterogeneity, and treatment options, while also comparing it to genetically related HLH.

Chimeric Antigen Receptor (CAR) T-Cell Therapy in Hematologic Malignancies: Clinical Implications and Limitations

Chimeric antigen receptor (CAR) T-cell therapy has become a powerful treatment option in B-cell and plasma cell malignancies, and many patients have benefited from its use. To date, six CAR T-cell products have been approved by the FDA and EMA, and many more are being developed and investigated in clinical trials. The whole field of adoptive cell transfer has experienced an unbelievable development process, and we are now at the edge of a new era of immune therapies that will have its impact beyond hematologic malignancies. Areas of interest are, e.g., solid oncology, autoimmune diseases, infectious diseases, and others. Although much has been achieved so far, there is still a huge effort needed to overcome significant challenges and difficulties. We are witnessing a rapid expansion of knowledge, induced by new biomedical technologies and CAR designs. The era of CAR T-cell therapy has just begun, and new products will widen the therapeutic landscape in the future. This review provides a comprehensive overview of the clinical applications of CAR T-cells, focusing on the approved products and emphasizing their benefits but also indicating limitations and challenges.

Consensus recommendations on the management of toxicity associated with CD3×CD20 bispecific antibody therapy

ABSTRACT

Bispecific antibodies (BsAb) that target CD3 and CD20 represent a new milestone in the treatment of patients with B-cell non-Hodgkin lymphoma. These drugs have demonstrated remarkable single-agent activity in patients with heavily pretreated disease, and 3 drugs have so far received regulatory approvals in various countries. However, BsAbs can potentially lead to severe toxicity associated with T-cell activation, particularly cytokine release syndrome (CRS). The anticipated widespread use of these off-the-shelf products poses challenges for implementation and highlights the need for guidance in anticipating, mitigating, and managing adverse events. In clinical trials, guidance for the evaluation and treatment of CRS and neurotoxicity associated with BsAb therapy has been modeled after algorithms originally created for chimeric antigen receptor (CAR) T-cell therapies and other immune effector therapies, yet notable differences in timing, quality, and severity exist between the toxicities of BsAbs and CAR T-cell therapies. We therefore convened an international panel of academic and community practice physicians, advanced practitioners, registered nurses, and pharmacists with experience using CD3×CD20 BsAbs in clinical trial and off-trial settings to provide comprehensive, consensus-based recommendations specific to the assessment and management of CD3×CD20 BsAb-related toxicities.

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

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

Chimeric Antigen Receptor T Cells in the Treatment of Multiple Myeloma

Chimeric antigen receptor T cells (CARTs) represent another powerful way to leverage the immune system to fight malignancy. Indeed, in multiple myeloma, the high response rate and duration of response to B cell maturation antigen-targeted therapies in later lines of disease has led to 2 Food and Drug Administration (FDA) drug approvals and opened the door to the development of this drug class. This review aims to provide an update on the 2 FDA-approved products, summarize the data for the most promising next-generation multiple myeloma CARTs, and outline current challenges in the field and potential solutions.

The Implementation of Chimeric Antigen Receptor (CAR) T-cell Therapy in Pediatric Patients: Where Did We Come From, Where Are We Now, and Where are We Going?

CD19-directed Chimeric Antigen Receptor (CAR) T-cell therapy has revolutionized the treatment of patients with B-cell acute lymphoblastic leukemia (B-ALL). Somewhat uniquely among oncologic clinical trials, early clinical development occurred simultaneously in both children and adults. In subsequent years however, the larger number of adult patients with relapsed/refractory (r/r) malignancies has led to accelerated development of multiple CAR T-cell products that target a variety of malignancies, resulting in six currently FDA-approved for adult patients. By comparison, only a single CAR-T cell therapy is approved by the FDA for pediatric patients: tisagenlecleucel, which is approved for patients ≤ 25 years with refractory B-cell precursor ALL, or B-cell ALL in second or later relapse. Tisagenlecleucel is also under evaluation in pediatric patients with relapsed/refractory B-cell non-Hodgkin lymphoma, but is not yet been approved for this indication. All the other FDA-approved CD19-directed CAR-T cell therapies available for adult patients (axicabtagene ciloleucel, brexucabtagene autoleucel, and lisocabtagene maraleucel) are currently under investigations among children, with preliminary results available in some cases. As the volume and complexity of data continue to grow, so too does the necessity of rapid assimilation and implementation of those data. This is particularly true when considering "atypical" situations, e.g. those arising when patients do not precisely conform to the profile of those included in pivotal clinical trials, or when alternative treatment options (e.g. hematopoietic stem cell transplantation (HSCT) or bispecific T-cell engagers (BITEs)) are also available. We have therefore developed a relevant summary of the currently available literature pertaining to the use of CD19-directed CAR-T cell therapies in pediatric patients, and sought to provide guidance for clinicians seeking additional data about specific clinical situations.

Hemophagocytic lymphohistiocytosis: A disorder of T cell activation, immune regulation, and distinctive immunopathology

Hemophagocytic lymphohistiocytosis (HLH) is a disorder that has been recognized since the middle of the last century. In recent decades, increasing understanding of the genetic roots and pathophysiology of HLH has led to improved diagnosis and treatment of this once universally fatal disorder. HLH is best conceptualized as a maladaptive state of excessive T cell activation driving life-threatening myeloid cell activation, largely via interferon-gamma (IFN-γ). In familial forms of HLH (F-HLH), inherited defects of lymphocyte cytotoxic biology underlie excessive T cell activation, demonstrating the importance of the perforin/granzyme pathway as a negative feedback loop limiting acute T cell activation in response to environmental factors. HLH occurring in other contexts and without apparent inherited genetic predisposition remains poorly understood, though it may share some downstream aspects of pathophysiology including excessive IFN-γ action and activation of innate immune effectors. Iatrogenic forms of HLH occurring after immune-activating therapies for cancer are providing new insights into the potential toxicities of inadequately controlled T cell activation. Diagnosing HLH increasingly relies on context-specific measures of T cell activation, IFN-γ activity, and inflammation. Treatment of HLH largely relies on cytotoxic chemotherapy, though targeted therapies against T cells, IFN-γ, and other cytokines are increasingly utilized.

INSPIRED Symposium Part 4B: Chimeric Antigen Receptor T Cell Correlative Studies-Established Findings and Future Priorities

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of B cell malignancies, with multiple CAR T cell products approved for numerous indications by regulatory agencies worldwide. However, significant work remains to be done to enhance these treatments. In March 2023, a group of experts in CAR T cell therapy assembled at the National Institutes of Health in Bethesda, Maryland at the Insights in Pediatric CAR T Cell Immunotherapy: Recent Advances and Future Directions (INSPIRED) Symposium to identify key areas for research for the coming years. In session 4B, correlative studies to be incorporated into future clinical trials and real-world settings were discussed. Active areas of research identified included (1) optimizing CAR T cell product manufacturing; (2) ensuring adequate lymphodepletion prior to CAR T cell administration; (3) overcoming immunoregulatory cells and tumor stroma present in the tumor microenvironment, particularly in solid tumors; (4) understanding tumor intrinsic properties that lead to CAR T cell immunotherapy resistance; and (5) uncovering biomarkers predictive of treatment resistance, treatment durability, or immune-related adverse events. Here we review the results of previously published clinical trials and real-world studies to summarize what is currently known about each of these topics. We then outline priorities for future research that we believe will be important for improving our understanding of CAR T cell therapy and ultimately leading to better outcomes for patients.

Filgrastim-induced hemophagocytic lymphohistiocytosis in a patient with mantle cell lymphoma: A case report

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disease potentially induced by various causes. Very few reports have described HLH induced by granulocyte colony-stimulating factor (G-CSF) and those few previous reports have uniformly indicated that continuing G-CSF is unfeasible once HLH has been induced. A 52-year-old Japanese man who had been diagnosed with mantle cell lymphoma with systemic and central nervous system involvements received rituximab, hyper-fractionated cyclophosphamide, vincristine, Adriamycin and dexamethasone (R-HCVAD)/methotrexate and cytarabine. During the second cycle of R-HCVAD, the patient developed severe back pain, thrombocytopenia, elevated serum lactate dehydrogenase and ferritin levels, and hemophagocytosis in the bone marrow. Complete remission (CR) of mantle cell lymphoma was confirmed on whole-body computed tomography, brain magnetic resonance imaging, and bone marrow biopsy. The patient was diagnosed with HLH induced by filgrastim. HLH recovered with intravenous methylprednisolone at 1 g/day for 3 days, followed by oral prednisolone tapered off over 5 days. The patient continued chemotherapy with a change in the G-CSF formulation from filgrastim to lenograstim and prophylactic administration of corticosteroids. He safely completed scheduled chemotherapy without recurrence of HLH and successfully maintained CR of lymphoma. Although rare, G-CSF potentially induces HLH. Changing the G-CSF formulation and steroid prophylaxis may allow safe continuation of G-CSF.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Hematopoiesis and immune reconstitution after CD19 directed chimeric antigen receptor T-cells (CAR-T): A comprehensive review on incidence, risk factors and current management

Impaired function of hematopoiesis after treatment with chimeric antigen T-cells (CAR-T) is a frequent finding and can interest a wide range of patients, regardless of age and underlying disease. Trilinear cytopenias, as well as hypogammaglobulinemia, B-cell aplasia, and T-cell impairment, can severely affect the infectious risk of CAR-T recipients, as well as their quality of life. In this review, we provide an overview of defects in hematopoiesis after CAR-T, starting with a summary of different definitions and thresholds. We then move to summarize the main pathogenetic mechanisms of cytopenias, and we offer insight into cytomorphological aspects, the role of clonal hematopoiesis, and the risk of secondary myeloid malignancies. Subsequently, we expose the major findings and reports on T-cell and B-cell quantitative and functional impairment after CAR-T. Finally, we provide an overview of current recommendations and leading experiences regarding the management of cytopenias and defective B- and T-cell function.

INSPIRED Symposium Part 3: Prevention and Management of Pediatric Chimeric Antigen Receptor T Cell-Associated Emergent Toxicities

Chimeric antigen receptor (CAR) T cell (CAR-T) therapy has emerged as a revolutionary cancer treatment modality, particularly in children and young adults with B cell malignancies. Through clinical trials and real-world experience, much has been learned about the unique toxicity profile of CAR-T therapy. The past decade brought advances in identifying risk factors for severe inflammatory toxicities, investigating preventive measures to mitigate these toxicities, and exploring novel strategies to manage refractory and newly described toxicities, infectious risks, and delayed effects, such as cytopenias. Although much progress has been made, areas needing further improvements remain. Limited guidance exists regarding initial administration of tocilizumab with or without steroids and the management of inflammatory toxicities refractory to these treatments. There has not been widespread adoption of preventive strategies to mitigate inflammation in patients at high risk of severe toxicities, particularly children. Additionally, the majority of research related to CAR-T toxicity prevention and management has focused on adult populations, with only a few pediatric-specific studies published to date. Given that children and young adults undergoing CAR-T therapy represent a unique population with different underlying disease processes, physiology, and tolerance of toxicities than adults, it is important that studies be conducted to evaluate acute, delayed, and long-term toxicities following CAR-T therapy in this younger age group. In this pediatric-focused review, we summarize key findings on CAR-T therapy-related toxicities over the past decade, highlight emergent CAR-T toxicities, and identify areas of greatest need for ongoing research.

Long-term survivorship care after CAR-T cell therapy

While cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome are well-recognized acute toxicities of chimeric antigen receptor (CAR) T cell therapy, these complications have become increasingly manageable by protocolized treatment algorithms incorporating the early administration of tocilizumab and corticosteroids. As CAR-T cell therapy expands to new disease indications and the number of long-term survivors steadily increases, there is growing recognition of the need to appropriately evaluate and manage the late effects of CAR-T cell therapy, including late-onset or persistent neurotoxicity, prolonged cytopenias, delayed immune reconstitution and infections, subsequent malignancies, organ dysfunction, psychological distress, and fertility implications. In this review, we provide a practical approach to the long-term survivorship care of the CAR-T cell recipient, with a focus on the optimal strategies to address the common and challenging late complications affecting this unique population.

Chimeric Antigen Receptor T Cell Therapy for Myeloma: Where Are We Now and What Is Needed to Move Chimeric Antigen Receptor T Cells Forward to Earlier Lines of Therapy? Expert Panel Opinion from the American Society for Transplantation and Cellular Therapy

Since 2021, 2 B cell maturation antigen (BCMA)-directed chimeric antigen receptor T cell (CAR-T) therapies-idecabtagene vicleucel (ide-cel), and ciltacabtagene autoleucel (cilta-cel)-have been approved by the US Food and Drug Administration (FDA) for treating relapsed or refractory multiple myeloma (RRMM) after 4 or more prior lines of therapy, including an immunomodulatory drug, a proteasome inhibitor, and an anti-CD38 antibody. The 2 products have shown unprecedented activity in RRMM, but relapses remain common, and access to and safety of CAR-T therapy in patients with rapidly progressing advanced disease are not ideal. Sequencing CAR-T therapy with other options, including the 2 recently approved BCMA-directed T cell-engaging bispecific antibodies teclistamab and elranatamab, has become increasingly challenging owing to data showing inferior outcomes from CAR-T therapy after prior BCMA-directed therapy. This has led to the consideration of CAR-T therapy earlier in the course of disease for myeloma, when T cells are potentially healthier and the myeloma is less aggressive. To address the question of earlier use of CAR-T therapy, several trials are either ongoing or planned, and results have recently been reported for 2 randomized trials of CAR-T therapy showing improved progression-free survival compared to standard of care therapy in second-line (CARTITUDE-4) or third-line therapy (KarMMA-3). With the anticipation of the FDA possibly expanding approval of CAR-T to earlier lines of myeloma therapy, the American Society for Transplantation and Cellular Therapy convened a group of experts to provide a comprehensive review of the studies that led to the approval of CAR-T therapy in late-line therapy for myeloma, discuss the recently reported and ongoing studies designed to move CAR-T therapy to earlier lines of therapy, and share insights and considerations for sequencing therapy and optimization of patient selection for BCMA-directed therapies in current practice.

Building safety into CAR-T therapy

Chimeric antigen receptor T cell (CAR-T) therapy is an innovative immunotherapeutic approach that utilizes genetically modified T-cells to eliminate cancer cells using the specificity of a monoclonal antibody (mAb) coupled to the potent cytotoxicity of the T-lymphocyte. CAR-T therapy has yielded significant improvements in relapsed/refractory B-cell malignancies. Given these successes, CAR-T has quickly spread to other hematologic malignancies and is being increasingly explored in solid tumors. From early clinical applications to present day, CAR-T cell therapy has been accompanied by significant toxicities, namely cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and on-target off-tumor (OTOT) effects. While medical management has improved for CRS and ICANS, the ongoing threat of refractory symptoms and unanticipated idiosyncratic toxicities highlights the need for more powerful safety measures. This is particularly poignant as CAR T-cell therapy continues to expand into the solid tumor space, where the risk of unpredictable toxicities remains high. We will review CAR-T as an immunotherapeutic approach including emergence of unique toxicities throughout development. We will discuss known and novel strategies to mitigate these toxicities; additional safety challenges in the treatment of solid tumors, and how the inducible Caspase 9 "safety switch" provides an ideal platform for continued exploration.

Long-term follow-up of CD19-CAR T-cell therapy in children and young adults with B-ALL

The tremendous successes of CD19-directed CAR T cells in children and young adults with B-cell acute lymphoblastic leukemia (B-ALL) has led to the more widespread use of this important treatment modality. With an ability to induce remission and potentially lead to long-term survival in patients with multiply relapsed/chemotherapy refractory disease, more children are now receiving this therapy with the hope of inducing a long-term durable remission (with or without consolidative hematopoietic cell transplantation). While overcoming the acute toxicities was critical to its broad implementation, the emerging utilization requires close evaluation of subacute and delayed toxicities alongside a consideration of late effects and issues related to survivorship following CAR T cells. In this underexplored area of toxicity monitoring, this article reviews the current state of the art in relationship to delayed toxicities while highlighting areas of future research in the study of late effects in children and young adults receiving CAR T cells.

Inpatient recognition and management of HLH

Hemophagocytic lymphohistiocytosis (HLH) is one of the life-threatening emergencies that a hematologist may be called upon to diagnose and manage. It is a hyperinflammatory process that develops in patients with genetic abnormalities, hematologic malignancies, chronic inflammatory states, or infections. The main clinical challenges are recognizing HLH, determining whether the immune response is aberrant or appropriate, and deciding upon therapy. Patients may present with fever, central nervous system symptoms, cytopenias, or elevated liver enzymes. Recognizing HLH is challenging because its features overlap with numerous systemic disorders, thus requiring a high level of suspicion and timely investigations to confirm the diagnosis and detect the underlying trigger. Once HLH is diagnosed, careful consideration of immunosuppressive therapy's potential benefit versus harm is necessary. Such therapy can sometimes be tailored to the underlying trigger. In the acute setting, the competing pressures of completing a thorough diagnostic process (including evaluation for the presence of lymphoma and infection) and the need for expedited treatment must be balanced. During the management of an HLH patient, continuous vigilance for the presence of as-yet unrecognized disease triggers, monitoring response, and identifying emerging complications is critical. This review will discuss the recognition and management of HLH in the inpatient setting.

Recognizing, defining, and managing CAR-T hematologic toxicities

Autologous CAR-T cell therapy (CAR-T) has improved outcomes for patients with B-cell malignancies. It is associated with the well-described canonical toxicities cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), which may be abrogated by corticosteroids and the anti-IL6 receptor antagonist tocilizumab. Practitioners and researchers should be aware of additional toxicities. Here we review current understanding and management of hematologic toxicities after CAR-T, including cytopenias, coagulopathies, bleeding and clotting events, hemophagocytic-lymphohistiocytosis, and tumor lysis syndrome. We pay particular attention to cytopenias, recently termed immune effector cell-associated hematological toxicity (ICAHT). While the "H" is silent, hematotoxicity is not: ICAHT has the highest cumulative incidence of all immune adverse events following CAR-T. Early cytopenia (day 0-30) is closely linked to lymphodepleting chemotherapy and CRS-related inflammatory stressors. Late ICAHT (after day 30) can present either with or without antecedent count recovery (e.g., "intermittent" vs "aplastic" phenotype), and requires careful evaluation and management strategies. Growth factor support is the mainstay of treatment, with recent evidence demonstrating safety and feasibility of early granulocyte colony-stimulating factor (G-CSF) (e.g., within week 1). In G-CSF refractory cases, autologous stem cell boosts represent a promising treatment avenue, if available. The CAR-HEMATOTOX scoring system, validated for use across lymphoid malignancies (B-NHL, multiple myeloma), enables pretherapeutic risk assessment and presents the potential for risk-adapted management. Recent expert panels have led to diagnostic scoring criteria, severity grading systems, and management strategies for both ICAHT and the recently termed immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS), now clarified and defined as a distinct entity from CRS.

Managing side effects: guidance for use of immunotherapies in multiple myeloma

Chimeric antigen receptor T-cell therapy and bispecific T-cell recruiting antibodies have transformed the treatment landscape for relapsed/refractory multiple myeloma, with B-cell maturation antigen being the most common target and other targets in clinical development. However, these therapies are associated with unique and severe toxicities, including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), delayed neurotoxicity, cytopenias, and infection. In addition, immune effector cell-associated hemophagocytic lymphohistiocytosis (HLH)-like syndrome (IEC-HS), which exhibits overlap between CRS and HLH, can be challenging to diagnose and treat. In this review, we provide an overview of toxicities associated with novel immunotherapies for treatment of multiple myeloma and describe management recommendations. The pathophysiology and risk factors behind these toxicities are not yet comprehensively understood. Based on consensus recommendations, treatment for CRS consists of tocilizumab and steroids, while treatment for ICANS includes steroids and anakinra in severe cases. Management of cytopenias and infection is similar to post-hematopoietic cell transplantation principles with antimicrobial prophylaxis, growth factor support, immunoglobulin replacement, and vaccinations. In contrast, effective treatments for delayed neurotoxicity and IEC-HS are lacking, although steroids and anakinra are commonly used. Management of all these toxicities should include a broad differential and multidisciplinary collaboration with infectious diseases, neurology, and/or critical care providers.

Immune checkpoint inhibitor-associated hemophagocytic lymphohistiocytosis in a patient with chronic lymphocytic leukemia

Haemophagocytic lymphohistiocytosis (HLH) is a rare complication of immune checkpoint inhibitor therapy. A 55-year-old male with stable chronic lymphocytic leukemia presented with fevers and symptomatic anaemia after nine cycles of nivolumab for metastatic melanoma. Investigations were consistent with autoimmune haemolytic anemia and corticosteroids were initiated. Thrombocytopenia and elevated liver enzymes without evidence of chronic lymphocytic leukaemia transformation was present. Ferritin was elevated, and thus HLH was considered and subsequently confirmed on a bone marrow biopsy. Corticosteroid monotherapy was continued, with resolution of fevers and improvement in cytopenias and liver enzymes. A six month corticosteroid tapering regimen was initiated, and he remains in HLH remission. This case highlights the importance of prompt recognition of immune checkpoint inhibitor-related HLH in patients with concurrent haematological malignancy.

Infections after chimeric antigen receptor (CAR)-T-cell therapy for hematologic malignancies

BACKGROUND

Chimeric antigen receptor (CAR)-T-cell therapies have revolutionized the management of acute lymphoblastic leukemia, non-Hodgkin lymphoma, and multiple myeloma but come at the price of unique toxicities, including cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, and long-term "on-target off-tumor" effects.

METHODS

All of these factors increase infection risk in an already highly immunocompromised patient population. Indeed, infectious complications represent the key determinant of non-relapse mortality after CAR-T cells. The temporal distribution of these risk factors shapes different infection patterns early versus late post-CAR-T-cell infusion. Furthermore, due to the expression of their targets on B lineage cells at different stages of differentiation, CD19, and B-cell maturation antigen (BCMA) CAR-T cells induce distinct immune deficits that could require different prevention strategies. Infection incidence is the highest during the first month post-infusion and subsequently decreases thereafter. However, infections remain relatively common even a year after infusion.

RESULTS

Bacterial infections predominate early after CD19, while a more equal distribution between bacterial and viral causes is seen after BCMA CAR-T-cell therapy, and fungal infections are universally rare. Cytomegalovirus (CMV) and other herpesviruses are increasingly breported, but whether routine monitoring is warranted for all, or a subgroup of patients, remains to be determined. Clinical practices vary substantially between centers, and many areas of uncertainty remain, including CMV monitoring, antibacterial and antifungal prophylaxis and duration, use of immunoglobulin replacement therapy, and timing of vaccination.

CONCLUSION

Risk stratification tools are available and may help distinguish between infectious and non-infectious causes of fever post-infusion and predict severe infections. These tools need prospective validation, and their integration in clinical practice needs to be systematically studied.

[Diagnostics and treatment of hemophagocytic lymphohistiocytosis]

Hemophagocytic lymphohistiocytosis (HLH) is a hyperferritinemic hyperinflammatory syndrome. A primary hereditary form can be distinguished from a secondary acquired form. In adults the secondary form accounts for the vast majority of cases. Infections, malignancies and autoimmune disorders are common triggering factors of secondary HLH. Persistent fever, bicytopenia or pancytopenia and splenomegaly represent major symptoms in HLH and occur in virtually all patients. The diagnosis of HLH is made on the basis of the HLH-2004 criteria. The probability of the presence of HLH can be estimated using the HScore. Patients with HLH require immunosuppressive treatment. Hence, high doses of corticosteroids represent the cornerstone of treatment. Furthermore, immunoglobulins, anakinra, ruxolitinib or etoposide are given depending on the triggering factor. The course and prognosis of HLH are dependent on the early initiation of treatment, the triggering factor and the response to treatment.

"Hurdles race for CAR T-cell therapy in digestive tract cancer"

Digestive tract cancers (DTC) belong to the most investigated family of tumors. The incidence, prevalence, and mortality rate of DTC remain high, especially for patients with pancreatic cancer. Even though immunotherapy such as immune checkpoint inhibitors (ICI) have revolutionized the treatment of solid cancer types, ICI are still restricted to a very small group of patients and seem to be more efficacious in combination with chemotherapy. Cellular immunotherapy such as CAR T-cell therapy has entered clinical routine in hematological malignancies with outstanding results. There is growing interest on translating this kind of immunotherapy and success into patients with solid malignancies, such as DTC. This review attempts to describe the major advances in preclinical and clinical research with CAR T cells in DTC, considering the most relevant hurdles in each subtype of DTC.

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

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

Immune Effector Cell-Associated HLH-like Syndrome: A Review of the Literature of an Increasingly Recognized Entity

Since CAR-T cell therapy was initially approved in 2017, its use has become more prevalent and so have its side effects. CAR-T-related HLH, also named immune effector cell-associated HLH-like syndrome (IEC-HS), is a rare but fatal toxicity if not recognized promptly. We conducted a review of the literature in order to understand the prevalence of IEC-HS as well as clarify the evolution of the diagnostic criteria and treatment recommendations. IEC-HS occurrence varies between CAR-T cell products and the type of malignancy treated. Diagnosis can be challenging as there are no standardized diagnostic criteria, and its clinical features can overlap with cytokine release syndrome and active hematological disease. Suggested treatment strategies have been extrapolated from prior experience in HLH and include anakinra, corticosteroids and ruxolitinib. IEC-HS is a potentially fatal toxicity associated with CAR-T cell therapy. Early recognition with reliable diagnostic criteria and prompt implementation of treatment specific to IEC-HS is imperative for improving patient outcomes.

Bone Marrow Aplasia after CAR-T-Cell Therapy for Relapsed/Refractory Burkitt's Lymphoma

Chimeric antigen receptor T-cells (CAR-T) are now a standard approach for treating relapsed/refractory B-cell lymphomas. Immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS) is a newly described entity that can manifest following CAR-T. Bone marrow (BM) aplasia is an uncommon manifestation of IEC-HS reported after CAR-T-cell therapy and is defined as the reduction or absence of hematopoietic progenitor cells resulting in severe pancytopenia. We describe the case of a 44-year-old female with relapsed/refractory Burkitt lymphoma (BL) who received treatment with lisocabtagene maraleucel with her post-CAR-T course complicated by cytokine release syndrome (CRS) and IEC-HS ultimately leading to persistent BM aplasia. She underwent a rescue allogeneic stem cell transplant but ultimately succumbed to progressive disease. IEC-HS is an increasingly recognized complication that occurs after CAR-T treatments that can result in aplasia, a dangerous complication with serious sequelae including infection, transfusion dependence, and high risk for hemorrhage. The underlying mechanism is poorly understood, and further studies are needed to understand how to treat it better.

[Treatment of hemophagocytic lymphohistiocytosis in patients in the intensive care unit]

Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome characterized by hyperferritinemia. A differentiation is made between hereditary and acquired forms. In contrast to children, almost all cases in adult patients consist of acquired secondary HLH. Infections, malignancies and autoimmune diseases are frequent triggers of secondary HLH. More recently, cases of HLH have also been described in association with immunotherapy, e.g., when using chimeric antigen receptor (CAR) T‑cell treatment. In critically ill patients in the intensive care unit (ICU), sepsis represents the major differential diagnosis of HLH due to the frequently similar clinical presentation. Sometimes both sepsis and HLH are present at the same time. An early diagnosis and timely initiation of immunosuppressive treatment are essential for the further course and prognosis of HLH. Therefore, HLH should be considered as a possible diagnosis in critically ill patients with persistent fever and additional compatible symptoms (e.g., splenomegaly, neurological symptoms) or laboratory parameters (e.g., hyperferritinemia, cytopenia of two or three cell lines, increased transaminases). The diagnosis of HLH is made on the basis of the HLH-2004 criteria. The HScore can be used to estimate the probability of the presence of HLH. Corticosteroids given at high doses are the cornerstone of HLH treatment. Furthermore, immunoglobulins, etoposide, anakinra or ruxolitinib can complement treatment depending on the HLH trigger. The course of HLH depends on the timely initiation of treatment, the underlying trigger and the response to treatment. Despite progress in terms of diagnostics and targeted treatment, the prognosis of critically ill HLH patients is still poor.

A comprehensive analysis of adverse events in the first 30 days of phase 1 pediatric CAR T-cell trials

The tremendous success of chimeric antigen receptor (CAR) T cells in children and young adults (CAYAs) with relapsed/refractory B-cell acute lymphoblastic leukemia is tempered by toxicities such as cytokine release syndrome (CRS). Despite expansive information about CRS, profiling of specific end-organ toxicities secondary to CAR T-cell therapy in CAYAs is limited. This retrospective, single-center study sought to characterize end-organ specific adverse events (AEs) experienced by CAYAs during the first 30 days after CAR T-cell infusion. AEs graded using Common Terminology Criteria for Adverse Events were retrospectively analyzed for 134 patients enrolled in 1 of 3 phase 1 CAR T-cell trials (NCT01593696, NCT02315612, and NCT03448393), targeting CD19 and/or CD22. A total of 133 patients (99.3%) experienced at least 1 grade ≥3 (≥Gr3) AE across 17 organ systems, of which 75 (4.4%) were considered dose- or treatment-limiting toxicities. Excluding cytopenias, 109 patients (81.3%) experienced a median of 3 ≥Gr3 noncytopenia (NC) AEs. The incidence of ≥Gr3 NC AEs was associated with the development and severity of CRS as well as preinfusion disease burden (≥ 25% marrow blasts). Although those with complete remission trended toward experiencing more ≥Gr3 NC AEs than nonresponders (median, 4 vs 3), nonresponders experiencing CRS (n = 17; 37.8%) had the highest degree of NC AEs across all patients (median, 7 vs 4 in responders experiencing CRS). Greater understanding of these toxicities and the ability to predict which patients may experience more toxicities is critical as the array of CAR T-cell therapies expand. This retrospective study was registered at www.clinicaltrials.gov as NCT03827343.

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

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