G-CSF does not worsen toxicities and efficacy of CAR-T cells in refractory/relapsed B-cell lymphoma

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.

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.

Infectious complications in pediatric patients undergoing CD19+CD22+ chimeric antigen receptor T-cell therapy for relapsed/refractory B-lymphoblastic leukemia

Chimeric antigen receptor T-cell (CAR-T) therapy is effective in the treatment of relapsed/refractory acute B-lymphoblastic leukemia (R/R B-ALL); however, patients who receive CAR-T therapy are predisposed to infections, with considerable detrimental effects on long-term survival rates and the quality of life of patients. This study retrospectively analyzed infectious complications in 79 pediatric patients with R/R B-ALL treated with CAR-T cells at our institution. Overall, 53 patients developed 88 infections. Nine patients experienced nine infections during lymphodepletion chemotherapy, 35 experienced 41 infections during the early phase (days 0-+ 30 after infusion), and 29 experienced 38 infections during the late phase (day + 31-+ 90 after infusion). Pathogens were identified in 31 infections, including 23 bacteria, seven viruses, and one fungus. Four patients were admitted to the intensive care unit for infection and one died. In a univariate analysis, there were ten factors associated with infection, including tumor load, lymphodepleting chemotherapy, neutrophil deficiency and lymphocyte reduction, cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), etc. In a multivariate analysis, CRS ≥ grade 3 was identified as a risk factor for infection (hazard ratio = 2.41, 95% confidence interval: 1.08-5.36, P = 0.031). Therefore, actively reducing the CRS grade may decrease the risk of infection and improve the long-term quality of life of these patients.

Improving the safety of CAR-T-cell therapy: The risk and prevention of viral infection for patients with relapsed or refractory B-cell lymphoma undergoing CAR-T-cell therapy

Chimeric antigen receptor (CAR) T-cell therapy, an innovative immunotherapeutic against relapsed/refractory B-cell lymphoma, faces challenges due to frequent viral infections. Despite this, a comprehensive review addressing risk assessment, surveillance, and treatment management is notably absent. This review elucidates immune response compromises during viral infections in CAR-T recipients, collates susceptibility risk factors, and deliberates on preventive strategies. In the post-pandemic era, marked by the Omicron variant, new and severe threats to CAR-T therapy emerge, necessitating exploration of preventive and treatment measures for COVID-19. Overall, the review provides recommendations for viral infection prophylaxis and management, enhancing CAR-T product safety and recipient survival.

Mucormycosis after CD19 chimeric antigen receptor T-cell therapy: results of a US Food and Drug Administration adverse events reporting system analysis and a review of the literature

Chimeric antigen receptor (CAR) T-cell therapy leads to durable remissions in relapsed B-cell cancers, but treatment-associated immunocompromise leads to a substantial morbidity and mortality risk from atypical infection. Mucormycosis is an aggressive and invasive fungal infection with a mortality risk of 40-80% in patients with haematological malignancies. In this Grand Round, we report a case of mucormycosis in a 54-year-old patient undergoing CAR T-cell therapy who reached complete clinical control of Mucorales with combined aggressive surgical debridement, antifungal pharmacotherapy, and reversal of underlying risk factors, but with substantial morbidity from extensive oro-facial surgery affecting the patient's speech and swallowing. For broader context, we present our case alongside an US Food and Drugs Administration adverse events reporting database analysis and a review of the literature to fully evaluate the clinical burden of mucormycosis in patients treated with CAR T-cell therapy. We discuss epidemiology, clinical features, diagnostic tools, and current frameworks for treatment and prophylaxis. We did this analysis to promote increased vigilance for mucormycosis among physicians specialising in CAR T-cell therapy and microbiologists and to illustrate the importance of early initiation of therapy to effectively manage this condition. Mucormycosis prevention and early diagnosis, through targeted surveillance and mould prevention in patients at highest risk and Mucorales-specific screening assays, is likely to be key to improving outcomes in patients treated with CAR T-cell therapy.

Transfusion needs after CAR T-cell therapy for large B-cell lymphoma: predictive factors and outcome (a DESCAR-T study)

ABSTRACT

Chimeric antigen receptor (CAR) T-cells targeting CD19 have been approved for the treatment of relapse/refractory large B-cell lymphoma. Hematotoxicity is the most frequent CAR T-cell-related adverse event. Transfusion support is a surrogate marker of severe cytopenias. Transfusion affects patients' quality of life, presents specific toxicities, and is known to affect immunity through the so-called transfusion-related immunomodulation that may affect CAR T-cell efficacy. We analyzed data from 671 patients from the French DESCAR-T registry for whom exhaustive transfusion data were available. Overall, 401 (59.8%) and 378 (56.3%) patients received transfusion in the 6-month period before and after CAR T-cell infusion, respectively. The number of patients receiving transfusion and the mean number of transfused products increased during the 6-month period before CAR T-cell infusion, peaked during the first month after infusion (early phase), and decreased over time. Predictive factors for transfusion at the early phase were age >60 years, ECOG PS ≥2, treatment with axicabtagene ciloleucel, pre-CAR T-cell transfusions, and CAR-HEMATOTOX score ≥2. Predictive factors for late transfusion (between 1 and 6 months after infusion) were pre-CAR T-cell transfusions, CAR-HEMATOTOX score ≥2, ICANS ≥3 (for red blood cells [RBC] transfusion), and tocilizumab use (for platelets transfusion). Early transfusions and late platelets (but not RBC) transfusions were associated with a shorter progression-free survival and overall survival. Lymphoma-related mortality and nonrelapse mortality were both increased in the transfused population. Our data shed light on the mechanisms of early and late cytopenia and on the potential impact of transfusions on CAR T-cell efficacy and toxicity.

Toxicities, intensive care management, and outcome of chimeric antigen receptor T cells in adults: an update

BACKGROUND

Chimeric antigen receptor T cells are a promising new immunotherapy for haematological malignancies. Six CAR-T cells products are currently available for adult patients with refractory or relapsed high-grade B cell malignancies, but they are associated with severe life-threatening toxicities and side effects that may require admission to ICU.

OBJECTIVE

The aim of this short pragmatic review is to synthesize for intensivists the knowledge on CAR-T cell therapy with emphasis on CAR-T cell-induced toxicities and ICU management of complications according to international recommendations, outcomes and future issues.

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.

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.

Recommendations on prevention of infections during chimeric antigen receptor T-cell and bispecific antibody therapy in multiple myeloma

Chimeric antigen receptor T (CAR T) cell and bispecific antibody therapies have shown unprecedented efficacy in heavily pretreated patients with multiple myeloma (MM). However, their use is associated with a significant risk of severe infections, which can be attributed to various factors such as hypogammaglobulinemia, neutropenia, lymphopenia, T-cell exhaustion, cytokine-release syndrome and immune-effector cell-associated neurotoxicity syndrome. As these therapies have been recently approved by regulatory agencies, it is crucial to establish practical guidelines for infection monitoring and prevention until robust data from prospective clinical trials become available. To address this issue, a panel of experienced investigators from the Academic Consortium to Overcome Multiple Myeloma through Innovative Trials (COMMIT) developed consensus recommendations for mitigating infections associated with CAR T-cell and bispecific antibody therapies in MM patients.

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 hematotoxicity: EHA/EBMT consensus grading and best practice recommendations

Hematological toxicity is the most common adverse event after chimeric antigen receptor (CAR) T-cell therapy. Cytopenias can be profound and long-lasting and can predispose for severe infectious complications. In a recent worldwide survey, we demonstrated that there remains considerable heterogeneity in regard to current practice patterns. Here, we sought to build consensus on the grading and management of immune effector cell-associated hematotoxicity (ICAHT) after CAR T-cell therapy. For this purpose, a joint effort between the European Society for Blood and Marrow Transplantation (EBMT) and the European Hematology Association (EHA) involved an international panel of 36 CAR T-cell experts who met in a series of virtual conferences, culminating in a 2-day meeting in Lille, France. On the basis of these deliberations, best practice recommendations were developed. For the grading of ICAHT, a classification system based on depth and duration of neutropenia was developed for early (day 0-30) and late (after day +30) cytopenia. Detailed recommendations on risk factors, available preinfusion scoring systems (eg, CAR-HEMATOTOX score), and diagnostic workup are provided. A further section focuses on identifying hemophagocytosis in the context of severe hematotoxicity. Finally, we review current evidence and provide consensus recommendations for the management of ICAHT, including growth factor support, anti-infectious prophylaxis, transfusions, autologous hematopoietic stem cell boost, and allogeneic hematopoietic cell transplantation. In conclusion, we propose ICAHT as a novel toxicity category after immune effector cell therapy, provide a framework for its grading, review literature on risk factors, and outline expert recommendations for the diagnostic workup and short- and long-term management.

Immune Effector Cell-Associated Hemophagocytic Lymphohistiocytosis-Like Syndrome

T cell-mediated hyperinflammatory responses, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), are now well-established toxicities of chimeric antigen receptor (CAR) T cell therapy. As the field of CAR T cells advances, however, there is increasing recognition that hemophagocytic lymphohistiocytosis (HLH)-like toxicities following CAR T cell infusion are occurring broadly across patient populations and CAR T cell constructs. Importantly, these HLH-like toxicities are often not as directly associated with CRS and/or its severity as initially described. This emergent toxicity, however ill-defined, is associated with life-threatening complications, creating an urgent need for improved identification and optimal management. With the goal of improving patient outcomes and formulating a framework to characterize and study this HLH-like syndrome, we established an American Society for Transplantation and Cellular Therapy panel composed of experts in primary and secondary HLH, pediatric and adult HLH, infectious disease, rheumatology and hematology, oncology, and cellular therapy. Through this effort, we provide an overview of the underlying biology of classical primary and secondary HLH, explore its relationship with similar manifestations following CAR T cell infusions, and propose the term "immune effector cell-associated HLH-like syndrome (IEC-HS)" to describe this emergent toxicity. We also delineate a framework for identifying IEC-HS and put forward a grading schema that can be used to assess severity and facilitate cross-trial comparisons. Additionally, given the critical need to optimize outcomes for patients experiencing IEC-HS, we provide insight into potential treatment approaches and strategies to optimize supportive care and delineate alternate etiologies that should be considered in a patient presenting with IEC-HS. By collectively defining IEC-HS as a hyperinflammatory toxicity, we can now embark on further study of the pathophysiology underlying this toxicity profile and make strides toward a more comprehensive assessment and treatment approach.

Tumor-intrinsic sensitivity to the pro-apoptotic effects of IFN-γ is a major determinant of CD4+ CAR T-cell antitumor activity

CD4⁺ T cells and CD4⁺ chimeric antigen receptor (CAR) T cells display highly variable antitumor activity in preclinical models and in patients; however, the mechanisms dictating how and when CD4⁺ T cells promote tumor regression are incompletely understood. With the help of functional intravital imaging, we report that interferon (IFN)-γ production but not perforin-mediated cytotoxicity was the dominant mechanism for tumor elimination by anti-CD19 CD4⁺ CAR T cells. Mechanistically, mouse or human CD4⁺ CAR T-cell-derived IFN-γ diffused extensively to act on tumor cells at distance selectively killing tumors sensitive to cytokine-induced apoptosis, including antigen-negative variants. In anti-CD19 CAR T-cell-treated patients exhibiting elevated CAR CD4:CD8 ratios, strong induction of serum IFN-γ was associated with increased survival. We propose that the sensitivity of tumor cells to the pro-apoptotic activity of IFN-γ is a major determinant of CD4⁺ CAR T-cell efficacy and may be considered to guide the use of CD4⁺ T cells during immunotherapy.

Infectious Complications of Targeted Therapies for Solid Cancers or Leukemias/Lymphomas

Background: Infections are well known complications of some targeted drugs used to treat solid organ cancer and hematological malignancies. Furthermore, Individual patient risk factors are associated with underlying pathologies, concomitant immunosuppressive treatment, prior treatment and use of anti-infective prophylaxis. Immune-related adverse events (irAEs) are frequent among patients treated with new targeted drugs. Objectives: In this narrative review, we present the current state of knowledge concerning the infectious complications occurring in patients treated with immune checkpoint inhibitors (ICIs), Bruton’s tyrosine kinase (BTK) inhibitors, phosphatidylinositol 3-kinase (PI3K) inhibitors, antiapoptotic protein BCL-2 inhibitors, Janus kinase inhibitors or CAR-T cell infusion. Sources: We searched for studies treating infectious complications of ICIs, BTK inhibitors, PI3K inhibitors, antiapoptotic protein BCL-2 inhibitors and CAR-T cell therapy. We included randomized, observational studies and case reports. Content: Immune-related adverse events (irAEs) are frequent among patients treated with new targeted drugs. Treatment of irAEs with corticosteroids and other immunosuppressive agents can lead to opportunistic infections. Bruton’s tyrosine kinase (BTK) inhibitors are associated with higher rate of infections, including invasive fungal infections. Implications: Infections, particularly fungal ones, are common in patients treated with BTK inhibitors even though most of the complications occurring among patients treated by ICIs or CART-cells infusion are associated with the treatment of side effects related to the use of these new treatments. The diagnosis of these infectious complications can be difficult and may require extensive investigations.

How I treat refractory/relapsed diffuse large B-cell lymphomas with CD19-directed chimeric antigen receptor T cells

Chimeric antigen receptor (CAR) T cells targeting CD19 represent a promising salvage immunotherapy for relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL), offering ~40% of long-term responses. In everyday clinical practice, haematologists involved in CAR T cell treatment of patients with R/R DLBCL have to deal with diagnostically complex cases and difficult therapeutic choices. The availability of novel immunotherapeutic agents for R/R DLBCL and recent advances in understanding CAR T-cell failure mechanisms demand a rational approach to identify the best choice for bridging therapy and managing post-CAR T-cell therapy relapses. Moreover, positron emission tomography/computerised tomography may result in false-positive interpretation, highlighting the importance of post-treatment biopsy. In this review, we discuss all above issues, presenting four instructive cases, with the aim to provide criteria and new perspectives for CAR T-cell treatment of DLBCL.

Associations of granulocyte colony-stimulating factor with toxicities and efficacy of chimeric antigen receptor T-cell therapy in relapsed or refractory multiple myeloma

BACKGROUND AIMS

Few studies have reported the associations of granulocyte colony-stimulating factor (G-CSF) with cytokine release syndrome (CRS), neurotoxic events (NEs) and efficacy after chimeric antigen receptor (CAR) T-cell therapy for relapsed or refractory (R/R) multiple myeloma (MM). We present a retrospective study performed on 113 patients with R/R MM who received single anti-BCMA CAR T-cell, combined with anti-CD19 CAR T-cell or anti-CD138 CAR T-cell therapy.

METHODS

Eight patients were given G-CSF after successful management of CRS, and no CRS re-occurred thereafter. Of the remaining 105 patients that were finally analyzed, 72 (68.6%) received G-CSF (G-CSF group), and 33 (31.4%) did not (non G-CSF group). We mainly analyzed the incidence and severity of CRS or NEs in two groups of patients, as well as the associations of G-CSF timing, cumulative dose and cumulative time with CRS, NEs and efficacy of CAR T-cell therapy.

RESULTS

Both groups of patients had similar duration of grade 3-4 neutropenia, and the incidence and severity of CRS or NEs.There were also no differences in the incidence and severity of CRS or NEs between patients with the timing of G-CSF administration ≤3 days and those >3 days after CAR T-cell infusion. The incidence of CRS was greater in patients receiving cumulative doses of G-CSF >1500 μg or cumulative time of G-CSF administration >5 days. Among patients with CRS, there was no difference in the severity of CRS between patients who used G-CSF and those who did not. The duration of CRS in anti-BCMA and anti-CD19 CAR T-cell-treated patients was prolonged after G-CSF administration. There were no significant differences in the overall response rate at 1 and 3 months between the G-CSF group and the non-G-CSF group.

CONCLUSIONS

Our results showed that low-dose or short-time use of G-CSF was not associated with the incidence or severity of CRS or NEs, and G-CSF administration did not influence the antitumor activity of CAR T-cell therapy.

Chimeric Antigen Receptor T-Cell Therapy and Hematopoiesis

Chimeric Antigen Receptor (CAR) T-cell therapy is a promising treatment option for patients suffering from B-cell- and plasma cell-derived hematologic malignancies and is being adapted for the treatment of solid cancers. However, CAR T is associated with frequently severe toxicities such as cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), macrophage activation syndrome (MAS), and prolonged cytopenias-a reduction in the number of mature blood cells of one or more lineage. Although we understand some drivers of these toxicities, their mechanisms remain under investigation. Since the CAR T regimen is a complex, multi-step process with frequent adverse events, ways to improve the benefit-to-risk ratio are needed. In this review, we discuss a variety of potential solutions being investigated to address the limitations of CAR T. First, we discuss the incidence and characteristics of CAR T-related cytopenias and their association with reduced CAR T-cell efficacy. We review approaches to managing or mitigating cytopenias during the CAR T regimen-including the use of growth factors, allogeneic rescue, autologous hematopoietic stem cell infusion, and alternative conditioning regimens. Finally, we introduce novel methods to improve CAR T-cell-infusion products and the implications of CAR T and clonal hematopoiesis.

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.

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.

Hematologic cytopenia post CAR T cell therapy: Etiology, potential mechanisms and perspective

Chimeric Antigen-Receptor (CAR) T-cell therapies have shown dramatic efficacy in treating relapsed and refractory cancers, especially B cell malignancies. However, these innovative therapies cause adverse toxicities that limit the broad application in clinical settings. Hematologic cytopenias, one frequently reported adverse event following CAR T cell treatment, are manifested as a disorder of hematopoiesis with decreased number of mature blood cells and subdivided into anemia, thrombocytopenia, leukopenia, and neutropenia, which increase the risk of infections, fatigue, bleeding, fever, and even fatality. Herein, we initially summarized the symptoms, etiology, risk factors and management of cytopenias. Further, we elaborated the cellular and molecular mechanisms underlying the initiation and progression of cytopenias following CAR T cell therapy based on previous studies about acquired cytopenias. Overall, this review will facilitate our understanding of the etiology of cytopenias and shed lights into developing new therapies against CAR T cell-induced cytopenias.

Infectious complications, immune reconstitution, and infection prophylaxis after CD19 chimeric antigen receptor T-cell therapy

CD19-targeted chimeric antigen receptor (CAR) T-cell becomes a breakthrough therapy providing excellent remission rates and durable disease control for patients with relapsed/refractory (R/R) hematologic malignancies. However, CAR T-cells have several potential side effects including cytokine release syndrome, neurotoxicities, cytopenia, and hypogammaglobulinemia. Infection has been increasingly recognized as a complication of CAR T-cell therapy. Several factors predispose CAR T-cell recipients to infection. Fortunately, although studies show a high incidence of infection post-CAR T-cells, most infections are manageable. In contrast to patients who undergo hematopoietic stem cell transplant, less is known about post-CAR T-cell immune reconstitution. Therefore, evidence regarding antimicrobial prophylaxis and vaccination strategies in these patients is more limited. As CAR T-cell therapy becomes the standard treatment for R/R B lymphoid malignancies, we should expect a larger impact of infections in these patients and the need for increased clinical attention. Studies exploring infection and immune reconstitution after CAR T-cell therapy are clinically relevant and will provide us with a better understanding of the dynamics of immune function after CAR T-cell therapy including insights into appropriate strategies for prophylaxis and treatment of infections in these patients. In this review, we describe infections in recipients of CAR T-cells, and discuss risk factors and potential mitigation strategies.

G-CSF induces CD15+ CD14+ cells from granulocytes early in the physiological environment of pregnancy and the cancer immunosuppressive microenvironment

Objectives

Recombinant granulocyte colony-stimulating factor (G-CSF) is frequently administered to patients with cancer to enhance granulocyte recovery post-chemotherapy. Clinical trials have also used G-CSF to modulate myeloid cell function in pregnancy and inflammatory diseases. Although the contribution of G-CSF to expanding normal granulocytes is well known, the effect of this cytokine on the phenotype and function of immunosuppressive granulocytic cells remains unclear. Here, we investigate the impact of physiological and iatrogenic G-CSF on an as yet undescribed granulocyte phenotype and ensuing outcome on T cells in the settings of cancer and pregnancy.

Methods

Granulocytes from patients treated with recombinant G-CSF, patients with late-stage cancer and women enrolled on a trial of recombinant G-CSF were phenotyped by flow cytometry. The ability and mechanism of polarised granulocytes to suppress T-cell proliferation were assessed by cell proliferation assays, flow cytometry and ELISA.

Results

We observed that G-CSF leads to a significant upregulation of CD14 expression on CD15⁺ granulocytes. These CD15⁺CD14⁺ cells are identified in the blood of patients with patients undergoing neutrophil mobilisation with recombinant G-CSF, and physiologically in women early in pregnancy or in those treated as a part of a clinical trial. Immunohistochemistry of tumor tissue or placental tissue identified the expression of G-CSF. The G-CSF upregulates the release of reactive oxygen species (ROS) in CD15⁺CD14⁺ cells leading to the suppression of T-cell proliferation.

Conclusions

G-CSF induces a population of ROS⁺ immunosuppressive CD15⁺CD14⁺ granulocytes. Strategies for how recombinant G-CSF can be scheduled to reduce effects on T-cell therapies should be developed in future clinical studies.

Cytopenia after CAR-T Cell Therapy-A Brief Review of a Complex Problem

Chimeric Antigen Receptor T-cell (CAR-T) immunotherapy has emerged as an efficacious and life extending treatment modality with high response rates and durable remissions in patients with relapsed and refractory non-Hodgkin lymphoma (NHL), follicular lymphoma, and B-cell acute lymphoblastic leukemia (B-ALL) as well as in other diseases. Prolonged or recurrent cytopenias after CAR-T therapy have increasingly been reported at varying rates, and the pathogenesis of this complication is not yet well-understood but is likely contributed to by multiple factors. Current studies reported are primarily retrospective, heterogeneous in terms of CAR-Ts used and diseases treated, non-uniform in definitions of cytopenias and durations for end points, and vary in terms of recommended management. Prospective studies and correlative laboratory studies investigating the pathophysiology of prolonged cytopenias will enhance our understanding of this phenomenon. This review summarizes knowledge of these cytopenias to date.

Management of adults and children receiving CAR T-cell therapy: 2021 best practice recommendations of the European Society for Blood and Marrow Transplantation (EBMT) and the Joint Accreditation Committee of ISCT and EBMT (JACIE) and the European Haematology Association (EHA)

BACKGROUND

Several commercial and academic autologous chimeric antigen receptor T-cell (CAR-T) products targeting CD19 have been approved in Europe for relapsed/refractory B-cell acute lymphoblastic leukemia, high-grade B-cell lymphoma and mantle cell lymphoma. Products for other diseases such as multiple myeloma and follicular lymphoma are likely to be approved by the European Medicines Agency in the near future.

DESIGN

The European Society for Blood and Marrow Transplantation (EBMT)-Joint Accreditation Committee of ISCT and EBMT (JACIE) and the European Haematology Association collaborated to draft best practice recommendations based on the current literature to support health care professionals in delivering consistent, high-quality care in this rapidly moving field.

RESULTS

Thirty-six CAR-T experts (medical, nursing, pharmacy/laboratory) assembled to draft recommendations to cover all aspects of CAR-T patient care and supply chain management, from patient selection to long-term follow-up, post-authorisation safety surveillance and regulatory issues.

CONCLUSIONS

We provide practical, clinically relevant recommendations on the use of these high-cost, logistically complex therapies for haematologists/oncologists, nurses and other stakeholders including pharmacists and health sector administrators involved in the delivery of CAR-T in the clinic.

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

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

Case Report: Sirolimus Alleviates Persistent Cytopenia After CD19 CAR-T-Cell Therapy

Chimeric antigen receptor T (CAR-T) cells show good efficacy in the treatment of relapsed and refractory B-cell tumors, such as acute B-cell leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL). The main toxicities of CAR-T include cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, cytopenia, and severe infection. It is still very difficult for CAR-T to kill tumor cells to the maximum extent and avoid damaging normal organs. Here, we report a case of DLBCL with persistent grade 4 thrombocytopenia and severe platelet transfusion dependence treated with CD19 CAR-T cells. We used sirolimus to inhibit the sustained activation of CAR-T cells and restore normal bone marrow hematopoiesis and peripheral blood cells. Moreover, sirolimus treatment did not affect the short-term efficacy of CAR-T cells, and DLBCL was in complete remission at the end of follow-up. In conclusion, sirolimus can represent a new strategy for the management of CAR-T cell therapy-related toxicity, including but not limited to hematotoxicity. However, further controlled clinical studies are required to confirm these findings.

CAR-T-OPENIA: Chimeric antigen receptor T-cell therapy-associated cytopenias

Chimeric antigen receptor (CAR) T-cell is the most recent version in the evolution of cellular therapy with promising responses, which has revolutionized the management of some hematological malignancies in the current times. As the clinical use has progressed rather rapidly since the first approval in 2017, toxicities beyond cytokine release syndrome and immune effector cell-associated neurological syndrome have surfaced. Cytopenias are common in <30 days ("early"), 30-90 days ("short-term") as well as >90 days ("prolonged"); and have clinical implications to patient care as well as resource utilization. We review the details of etiology, factors associated with cytopenias, and management considerations for patients with cytopenias for each of these time-frames. This would potentially serve as a clinical guide for hematological toxicity or CAR-T-OPENIA, which is commonly encountered with the use of CAR T-cell therapy.

CAR-T cell: Toxicities issues: Mechanisms and clinical management

CAR-T cells are modified T cells expressing a chimeric antigen receptor targeting a specific antigen. They have revolutionized the treatment of B cell malignancies (aggressive lymphomas, B-ALL), and this has raised hopes for application in many other pathologies (myeloma, AML, solid tumors, etc.). However, these therapies are associated with novel and specific toxicities (cytokine release syndrome and neurotoxicity). These complications, although mostly managed in a conventional hospitalization unit, can sometimes be life threatening, leading to admission of patients to the intensive care unit. Management relies mainly on anti-IL6R (tocilizumab) and corticosteroids. However, the optimal treatment regimen is still a matter of debate, and the management of the most severe forms is even less well codified. In addition to CRS and ICANS, infections, cytopenia and hypogammaglobulinemia are other frequent complications. This article reviews the mechanisms, risk factors, clinical presentation, and management of these toxicities.

[Prevention and management of infections in patients undergoing CAR T-cell therapy: Recommendations of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

Infections occurring after CAR T-cells are a common complication. At the acute phase of treatment following CAR T-cell infusion, the exact incidence of infections is unknown given the overlapping symptoms with cytokine release syndrome. The risk factors for infection include the malignant underlying disease and its multiple treatments, and an immunosuppressive state induced by CAR-T cells themselves and the treatment of their complications. During the twelfth edition of practice harmonization workshops of the Francophone society of bone marrow transplantation and cellular therapy (SFGM-TC), a working group focused its work on the management of post-CAR infectious complications. In this review we discuss anti-infection prophylaxis and vaccination of patients undergoing CAR T-cell therapy as well as a special chapter for the specific case of COVID-19. These recommendations apply to commercial CAR-T cells, in order to guide strategies for the management and prevention of infectious complications associated with this new therapeutic approach.

State of the CAR-T: Risk of Infections with Chimeric Antigen Receptor T-Cell Therapy and Determinants of SARS-CoV-2 Vaccine Responses

Chimeric antigen receptor T cell (CAR-T) therapy has shown unprecedented response rates in patients with relapsed/refractory (R/R) hematologic malignancies. Although CAR-T therapy gives hope to heavily pretreated patients, the rapid commercialization and cumulative immunosuppression of this therapy predispose patients to infections for a prolonged period. CAR-T therapy poses distinctive short- and long-term toxicities and infection risks among patients who receive CAR T-cells after multiple prior treatments, often including hematopoietic cell transplantation. The acute toxicities include cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome. The long-term B cell depletion, hypogammaglobulinemia, and cytopenia further predispose patients to severe infections and abrogate the remission success achieved by the living drug. These on-target-off-tumor toxicities deplete B-cells across the entire lineage and further diminish immune responses to vaccines. Early observational data suggest that patients with hematologic malignancies may not mount adequate humoral and cellular responses to SARS-CoV-2 vaccines. In this review, we summarize the immune compromising factors indigenous to CAR-T recipients. We discuss the immunogenic potential of different SARS-CoV-2 vaccines for CAR-T recipients based on the differences in vaccine manufacturing platforms. Given the lack of data related to the safety and efficacy of SARS-CoV-2 vaccines in this distinctively immunosuppressed cohort, we summarize the infection risks associated with Food and Drug Administration-approved CAR-T constructs and the potential determinants of vaccine responses. The review further highlights the potential need for booster vaccine dosing and the promise for heterologous prime-boosting and other novel vaccine strategies in CAR-T recipients. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

[Complications other than infections, CRS and ICANS following CAR T-cells therapy: Recommendations of the Francophone Society of bone marrow transplantation and cell therapy (SFGM-TC)]

CAR-T cells are an innovative treatment for an increasing number of patients, particularly since the extension of their indication to mantle lymphoma and multiple myeloma. Several complications of CAR T-cell therapy, that were first described as exceptional, have now been reported in series of patients, since its first clinical use in 2011. Among them, cardiac complications, delayed cytopenias, acute and chronic Graft versus Host Disease, and tumoral lysis syndrome are recognized as specific potent complications following CAR T-cells infusion. During the twelfth edition of practice harmonization workshops of the Francophone society of bone marrow transplantation and cellular therapy (SFGM-TC), a working group focused its work on the management of these complications with focuses the epidemiology, the physiopathology and the risk factors of these 4 side effects. Our recommendations apply to commercial CAR-T cells, in order to guide strategies for the management of complications associated with this new therapeutic approach.

Identifying and managing CAR T-cell-mediated toxicities: on behalf of an Italian CAR-T multidisciplinary team

INTRODUCTION

Chimeric antigen receptor (CAR)-T-cell therapy is a new treatment for patients with hematologic malignancies in which other therapies have failed.

AREAS COVERED

The review provides an overview for recognizing and managing the most acute toxicities related to CAR-T cells.

EXPERT OPINION

The development of immune-mediated toxicities is a common challenge of CAR-T therapy. The mechanism that determines this toxicity is still unclear, although an unfavorable tumor microenvironment and a pro-inflammatory state put patients at risk. The monitoring, diagnosis, and treatment of post-CAR-T toxicities must be determined and based on international guidelines and internal clinical practice. It is urgent to identify biomarkers that can identify patients at greater risk of developing complications. The adoption of consistent grading criteria is necessary to improve toxicity management strategies continually. The first-line therapy consists of supportive care and treatment with tocilizumab or corticosteroids. An early start of cytokine blockade therapies could mitigate toxicity. The plan will include cytokine release prophylaxis, a risk-adapted treatment, prevention of on-target/off-tumor effect, and a switch on/off CAR-T approach.

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

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

CAR-HEMATOTOX: A model for CAR T-cell related hematological toxicity in relapsed/refractory large B-cell lymphoma

Hematotoxicity represents a frequent chimeric antigen receptor (CAR) T-cell related adverse event and remains poorly understood. In this multicenter analysis, we studied patterns of hematopoietic reconstitution and evaluated potential predictive markers in 258 patients receiving Axicabtagene ciloleucel (Axi-cel) or Tisagenlecleucel (Tisa-cel) for relapsed/refractory large B-cell lymphoma. We observed profound (ANC<100/µl) and prolonged (≥day 21) neutropenia in 72 and 64% of patients respectively. The median duration of severe neutropenia (ANC<500/µl) was 9 days. We aimed to identify predictive biomarkers of hematotoxicity using the duration of severe neutropenia until day +60 as the primary endpoint. In the training cohort (n=58), we observed a significant correlation with baseline thrombocytopenia (r= -0.43, P=0.001) and hyperferritinemia (r=0.54, P<0.0001) on uni- and multivariate analysis. Incidence and severity of CRS, ICANS and peak cytokine levels were not associated with the primary endpoint. We calculated the CAR-HEMATOTOX model, which included markers associated with hematopoietic reserve (e.g. platelet count, hemoglobin and ANC) and baseline inflammation (e.g. C-reactive-protein, ferritin). This model was validated in two independent cohorts from Europe (n=91) and the USA (n=109), and discriminated patients with severe neutropenia ≥/<14 days (pooled validation: AUC=0.89, Sensitivity 89%, Specificity 68%). A high CAR-HEMATOTOX score resulted in a longer duration of neutropenia (12 vs. 5.5 days, P<0.001), and a higher incidence of severe thrombocytopenia (87% vs. 34%, P<0.001) and anemia (96% vs. 40%, P<0.001). The score implicates pre-CART bone marrow reserve and inflammatory state as key features associated with delayed cytopenia and will be useful for risk-adapted management of hematotoxicity.