Incidence and Risk Factors Associated with Infection after Chimeric Antigen Receptor T Cell Therapy for Relapsed/Refractory B-cell Malignancies

Invasive Fungal Disease After Chimeric Antigen Receptor-T Immunotherapy in Adult and Pediatric Patients

Invasive fungal diseases (IFDs) have been documented among the causes of post-chimeric antigen receptor-T (CAR-T) cell immunotherapy complications, with the incidence of IFDs in CAR-T cell therapy recipients being measured between 0% and 10%, globally. IFDs are notorious for their potentially life-threatening nature and challenging diagnosis and treatment. In this review, we searched the recent literature aiming to examine the risk factors and epidemiology of IFDs post-CAR-T infusion. Moreover, the role of antifungal prophylaxis is investigated. CAR-T cell therapy recipients are especially vulnerable to IFDs due to several risk factors that contribute to the patient's immunosuppression. Those include the underlying hematological malignancies, the lymphodepleting chemotherapy administered before the treatment, existing leukopenia and hypogammaglobinemia, and the use of high-dose corticosteroids and interleukin-6 blockers as countermeasures for immune effector cell-associated neurotoxicity syndrome and cytokine release syndrome, respectively. IFDs mostly occur within the first 60 days following the infusion of the T cells, but cases even a year after the infusion have been described. Aspergillus spp., Candida spp., and Pneumocystis jirovecii are the main cause of these infections following CAR-T cell therapy. More real-world data regarding the epidemiology of IFDs and the role of antifungal prophylaxis in this population are essential.

Shift from Widespread to Tailored Antifungal Prophylaxis in Lymphoma Patients Treated with CD19 CAR T Cell Therapy: Results from a Large Retrospective Cohort

Patients undergoing CD19 chimeric antigen receptor (CAR)-T cell therapy exhibit multiple immune deficits that may increase their susceptibility to infections. Invasive fungal infections (IFIs) are life-threatening events in the setting of hematologic diseases. However, there is ongoing debate regarding the optimal role and duration of antifungal prophylaxis in this specific patient population. The objective of this study was to provide a comprehensive overview of the evolution of IFI prophylactic strategies over time and to assess IFI incidence rates in a cohort of patients with relapsed or refractory (R/R) lymphoma treated with CAR-T cell therapy. A single-center retrospective study was conducted on a cohort of patients with R/R B cell lymphoma treated with CD19 CAR-T cell therapy between April 2016 and March 2023. Group A (April 2016-August 2020) consisted of patients primarily treated with fluconazole, irrespective of their individual IFI risk profile. In Group B (September 2020-March 2023) antifungal prophylaxis was recommended only for high-risk patients. Overall, 330 patients were included. Antifungal prophylaxis was prescribed to 119/142 (84%) patients in Group A and 58/188 (31%) in Group B (P < .001). Anti-mold azoles were prescribed to 8 (5.6%) patients in Group A and 21 (11.2%) patients in Group B. In Group A, 42 (29%) patients were switched to another antifungal, 9 (21%) because of toxicity, with 6 cases of transaminitis and 3 cases of prolonged QTc. In Group B, 21 (11.2%) patients were switched to the antifungal drug, mainly from fluconazole or micafungin to a mold-active agent following revised guidelines. No difference was found in liver toxicity between the two groups at infusion, day 10, and day 30. No significant differences were observed between the groups. IFIs following CAR-T cell therapy were rare, with 1 case of cryptococcal meningoencephalitis in group A (.7%) and 1 case of invasive aspergillosis in Group B (.5%), both occurring in patients on micafungin prophylaxis. In this large single-center cohort of patients with R/R lymphoma treated with CAR-T cells, we show that individualized prophylaxis, alongside careful management of CAR-T cell-related toxicities such as CRS, was associated with a very low IFI rate, avoiding the risk of unnecessary toxicities, drug-drug interactions, and high costs.

Mitigating and managing infection risk in adults treated with CAR T-cell therapy

Chimeric antigen receptor T-cell therapy (CAR-T) has transformed the treatment paradigm of relapsed/refractory B-cell malignancies. Yet, this therapy is not without toxicities. While the early inflammation-mediated toxicities are now better understood, delayed hematopoietic recovery and infections result in morbidity and mortality risks that persist for months following CAR-T. The predisposition to infections is a consequence of immunosuppression from the underlying disease, prior therapies, lymphodepletion chemotherapy, delayed hematopoietic recovery, B-cell aplasia, and delayed T-cell immune reconstitution. These risks and epidemiology can vary over a post-CAR-T timeline of early (<30 days), prolonged (30-90 days), or late (>90 days) follow-up. Antibacterial, antiviral, and antifungal prophylaxis; growth factors and stem cell boost to expedite count recovery; immunoglobulin replacement therapy; and possibly revaccination programs are important prevention strategies to consider for infection mitigation. Assessment of risk factors, evaluation, and treatment for pathogen(s) prevalent in a particular time frame post-CAR-T are important clinical considerations in patients presenting with clinical features suggestive of infectious pathology. As more data emerge on the topic, personalized risk assessments to inform the type and duration of prophylaxis use and planning interventions will continue to emerge. Herein, we review our current approach toward infection mitigation while recognizing that this continues to evolve and that there are differences among practices stemming from data availability limitations.

Survivorship in Chimeric Antigen Receptor T-Cell Therapy Recipients: Infections, Secondary Malignancies, and Non-Relapse Mortality

BACKGROUND

Chimeric antigen receptor (CAR) T-cell therapy has significantly advanced the treatment of hematologic malignancies, offering curative potential for patients with relapsed or refractory disease. However, the long-term survivorship of these patients is marked by unique challenges, particularly immune deficits and infectious complications, second primary malignancies (SPMs), and non-relapse mortality (NRM). Understanding and addressing these risks is paramount to improving patient outcomes and quality of life.

SUMMARY

This review explores the incidence and risk factors for NRM and long-term complications following CAR T-cell therapy. Infections are the leading cause of NRM, accounting for over 50% of cases, driven by neutropenia, hypogammaglobulinemia, and impaired cellular immunity. SPMs, including secondary myeloid and T-cell malignancies, are increasingly recognized, prompting the FDA to issue a black box warning, although their direct link to CAR T cells remains disputed. While CAR T-cell-specific toxicities like cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome contribute to morbidity, they represent only a minority of NRM cases. The management of these complications is critical as CAR T-cell therapy is being evaluated for broader use, including in earlier treatment lines and for non-malignant conditions like autoimmune diseases.

KEY MESSAGES

CAR T-cell therapy has revolutionized cancer treatment, but survivorship is complicated by infections, SPMs, and ultimately endangered by NRM. Prophylactic strategies, close monitoring, and toxicity management strategies are key to improving long-term outcomes.

Best Practice Considerations by The American Society of Transplant and Cellular Therapy: Infection Prevention and Management After Chimeric Antigen Receptor T Cell Therapy for Hematological Malignancies

Chimeric antigen receptor (CAR) T-cell therapy is rapidly advancing, offering promising treatments for patients with hematological malignancy. However, associated infectious complications remain a significant concern because of their contribution to patient morbidity and non-relapse mortality. Recent epidemiological insights shed light on risk factors for infections after CAR T-cell therapy. However, the available evidence is predominantly retrospective, highlighting a need for further prospective studies. Institutions are challenged with managing infections after CAR T-cell therapy but variations in the approaches taken underscore the importance of standardizing infection prevention and management protocols across different healthcare settings. Therefore, the Infectious Diseases Special Interest Group of the American Society of Transplantation and Cellular Therapy assembled an expert panel to develop best practice considerations. The aim was to guide healthcare professionals in optimizing infection prevention and management for CAR T-cell therapy recipients and advocates for early consultation of Infectious Diseases during treatment planning phases given the complexities involved. By synthesizing current evidence and expert opinion these best practice considerations provide the basis for understanding infection risk after CAR T-cell therapies and propose risk-mitigating strategies in children, adolescents, and adults. Continued research and collaboration will be essential to refining and effectively implementing these recommendations.

Infectious Complications Following CD30 Chimeric Antigen Receptor T-Cell Therapy in Adults

Infections are increasingly recognized as a common complication of chimeric antigen receptor (CAR) T-cell therapy. The incidence of clinically-defined infection after CD19.CAR T-cell therapy for relapsed/refractory lymphoma ranges from 60-90% in the first year after CAR T-cell therapy and is the most common cause for non-relapse mortality. However, infectious risk after CAR T-cell therapy targeting other malignancies is not well understood. Herein, we report for the first time, infectious complications after CD30.CAR T-cell treatment for patients with Hodgkin's lymphoma and peripheral T-cell lymphoma. Since CD30 is only expressed on a subset of activated T and B-cells, we hypothesized that CD30.CAR T-cell patients would have reduced incidence and severity of infections after infusion compared to CD19.CAR T-cell patients. We retrospectively evaluated all 64 patients who received CD30.CAR T-cells at a single institution between 2016-2021, and assessed infections within one year after cell infusion, comparing these data to a contemporary cohort of 50 patients who received CD19.CAR T-cells at the same institution between 2018-2021. 23 CD30.CAR T-cell patients (36%) and 18 CD19.CAR T-cell patients (36%) developed a microbiologically confirmed infection. Infection severity and bacterial infections were higher in the CD19.CAR T-cell group compared to CD30.CAR T-cell recipients who more commonly had grade 1 respiratory viral infections. Our data reflect expected outcomes for severity and infection type in CD19.CAR T-cell patients and provide a benchmark for comparison with the novel CD30.CAR T-cell product. Although our findings require replication in a larger cohort, they have implications for antimicrobial prophylaxis guidelines after CD30.CAR T-cell therapy.

KEY POINTS

1) The incidence of infections within the first year after CD30.CAR T-cell therapy was equivalent to that following CD19.CAR T-cell therapy2) Viral infections were more common after CD30.CAR T-cell therapy but bacterial infections predominated after CD19.CAR T-cell therapy.

Overview of infectious complications among CAR T- cell therapy recipients

Chimeric antigen receptor-modified T cell (CAR T-cell) therapy has revolutionized the management of hematological malignancies. In addition to impressive malignancy-related outcomes, CAR T-cell therapy has significant toxicity-related adverse events, including cytokine release syndrome (CRS), immune effector cell associated neurotoxicity syndrome (ICANS), immune effector cell-associated hematotoxicity (ICAHT), and opportunistic infections. Different CAR T-cell targets have different epidemiology and risk factors for infection, and these targets result in different long-term immunodeficiency states due to their distinct on-target and off- tumor effects. These effects are exacerbated by the use of multimodal immunosuppression in the management of CRS and ICANS. The most effective course of action for managing infectious complications involves determining screening, prophylactic, and monitoring strategies and understanding the role of immunoglobulin replacement and re-vaccination strategies. This involves considering the nature of prior immunomodulating therapies, underlying malignancy, the CAR T-cell target, and the development and management of related adverse events. In conclusion, we now have an increasing understanding of infection management for CAR T-cell recipients. As additional effector cells and CAR T-cell targets become available, infection management strategies will continue to evolve.

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.

Cytomegalovirus (CMV) Reactivation and CMV-Specific Cell-Mediated Immunity After Chimeric Antigen Receptor T-Cell Therapy

BACKGROUND

The epidemiology of cytomegalovirus (CMV) after chimeric antigen receptor-modified T-cell immunotherapy (CARTx) is poorly understood owing to a lack of routine surveillance.

METHODS

We prospectively enrolled 72 adult CMV-seropositive CD19-, CD20-, or BCMA-targeted CARTx recipients and tested plasma samples for CMV before and weekly up to 12 weeks after CARTx. We assessed CMV-specific cell-mediated immunity (CMV-CMI) before and 2 and 4 weeks after CARTx, using an interferon γ release assay to quantify T-cell responses to IE-1 and pp65. We tested pre-CARTx samples to calculate a risk score for cytopenias and infection (CAR-HEMATOTOX). We used Cox regression to evaluate CMV risk factors and evaluated the predictive performance of CMV-CMI for CMV reactivation in receiver operator characteristic curves.

RESULTS

CMV was detected in 1 patient (1.4%) before and in 18 (25%) after CARTx, for a cumulative incidence of 27% (95% confidence interval, 16.8-38.2). The median CMV viral load (interquartile range) was 127 (interquartile range, 61-276) IU/mL, with no end-organ disease observed; 5 patients received preemptive therapy based on clinical results. CMV-CMI values reached a nadir 2 weeks after infusion and recovered to baseline levels by week 4. In adjusted models, BCMA-CARTx (vs CD19/CD20) and corticosteroid use for >3 days were significantly associated with CMV reactivation, and possible associations were detected for lower week 2 CMV-CMI and more prior antitumor regimens. The cumulative incidence of CMV reactivation almost doubled when stratified by BCMA-CARTx target and use of corticosteroids for >3 days (46% and 49%, respectively).

CONCLUSIONS

CMV testing could be considered between 2 and 6 weeks in high-risk CARTx recipients.

Infections in haematology patients treated with CAR-T therapies: A systematic review and meta-analysis

A registered (PROSPERO - CRD42022346462) systematic review and meta-analysis was conducted of all-grade infections amongst adult patients receiving CAR-T therapy for haematological malignancy. Meta-analysis of pooled incidence, using random effects model, was conducted. Cochran's Q test examined heterogeneity. 2678 patients across 33 studies were included in the primary outcome. Forty-percent of patients (95% CI: 0.33 - 0.48) experienced an infection of any grade. Twenty-five percent of infection events (95% CI: 0.16 - 0.34) were severe. Late infections were as common as early infections (IRR = 0.86, 95% CI: 0.38 - 1.98). All-grade infections, bacterial and viral infections were highest in myeloma patients at 57%, 37% and 28% respectively. Patients with NHL more commonly experienced late infections. Pooled rate of invasive candidiasis/yeast infections was 2% in studies utilizing anti-yeast prophylaxis. This review identified a high rate of all-grade infections, moderate rate of severe infections, and myeloma as a high-risk haematological group.

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.

Predicting infections in patients with haematological malignancies treated with chimeric antigen receptor T-cell therapies: A systematic scoping review and narrative synthesis

BACKGROUND

Chimeric antigen receptor T cells (CAR-T cells) are increasingly used to treat haematological malignancies. Strategies for preventing infections in CAR-T-treated patients rely on expert opinions and consensus guidelines.

OBJECTIVES

This scoping review aimed to identify risk factors for infections in CAR-T-treated patients with haematological malignancies.

DATA SOURCES

A literature search utilized MEDLINE, EMBASE and Cochrane to identify relevant studies from conception until 30 September 2022.

STUDY ELIGIBILITY CRITERIA

Trials and observational studies were eligible.

PARTICIPANTS

Studies required ≥10 patients treated for haematological malignancy to report infection events (as defined by the study), and either (a) a descriptive, univariate or multivariate analysis of the relationship between infections event and a risk factors for infections, or (b) diagnostic performance of a biochemical/immunological marker in CAR-T-treated patients with infection.

METHODS

A scoping review was conducted in accordance with PRISMA guidelines.

DATA SOURCES

A literature search utilised MEDLINE, EMBASE and Cochrane to identify relevant studies from conception until September 30, 2022. Eligibility/Participants/Intervention: Trials and observational studies were eligible. Studies required ≥ 10 patients treated for haematological malignancy, to report infection events (as defined by the study), and either A) a descriptive, univariate or multivariate analysis of the relationship between infections event and a risk-factors for infections, or B) diagnostic performance of a biochemical/immunological marker in CAR-T treated patients with infection.

ASSESSMENT OF RISK OF BIAS

Bias assessment was undertaken according to Joanna Brigg's Institute criteria for observational studies.

METHODS OF DATA SYNTHESIS

Data were synthesized descriptively because of the heterogeneity of reporting.

RESULTS

A total of 1522 patients across 15 studies were identified. All-cause infections across haematological malignancies were associated with lines of prior therapy, steroid administration, immune-effector cell-associated neurotoxicity and treatment-emergent neutropenia. Procalcitonin, C-reactive protein and cytokine profiles did not reliably predict infections. Predictors of viral, bacterial and fungal infections were poorly canvassed.

DISCUSSION

Meta-analysis of the current literature is not possible because of significant heterogeneity in definitions of infections and risk factors, and small, underpowered cohort studies. Radical revision of how we approach reporting infections for novel therapies is required to promptly identify infection signals and associated risks in patients receiving novel therapies. Prior therapies, neutropenia, steroid administration and immune-effector cell-associated neurotoxicity remain the most associated with infections in CAR-T-treated patients.

Evaluation of the Diagnostic Performance of Plasma Metagenomic Next-Generation Sequencing in Febrile Events in the First 30 Days after Chimeric Antigen Receptor T Cell Infusion

Chimeric antigen receptor-modified T cell (CAR-T) therapy is a promising novel immunotherapy for hematologic malignancies, and the diagnosis of infection after CAR-T infusion (CTI) presents challenges for clinicians. Plasma metagenomic next-generation sequencing (mNGS) has been shown to be a reliable diagnostic approach for infection, especially in immunocompromised patients. We aimed to investigate the diagnostic performance of plasma mNGS for infection in the first 30 days after CTI. A cohort of 153 patients who experienced a total of 170 febrile events during the first 30 days post-CTI were enrolled. Of these events, 51 were evaluated with both mNGS and CDM and 119 were assessed by conventional detection methods (CDM) only. We also explored the epidemiology of infections and differences in infection complications in cases with severe (>2) and moderate (≤2) cytokine release syndrome (CRS). Cases with febrile events were clinically divided into an infection group (IG) (95 of 170; 55.9%) and a noninfection group (NIG) (75 of 170; 44.1%). The sensitivity and specificity of mNGS for the diagnosis of infectious complications in the first 30 days after CTI were 69.2% and 89.2%, respectively, with the sensitivity superior to that of culture (P < .001). More infection cases assessed with both mNGS and CDM than those assessed with CDM only were laboratory-confirmed (63.9% versus 11.9%; P < .001). The serum C-reactive protein level was higher and the IFN-γ level was lower in the IG group, particularly in cases with CRS grade ≤2. Infection is a common complication in the first 30 days after CTI. The addition of mNGS to CDM improved the diagnostic yield, and mNGS showed relatively high sensitivity and specificity in post-CAR-T therapy febrile events.

The burden of SARS-CoV-2 in patients receiving chimeric antigen receptor T cell immunotherapy: everything to lose

INTRODUCTION

Chimeric antigen receptor T (CAR-T) cell immunotherapy has revolutionized the prognosis of refractory or relapsed B-cell malignancies. CAR-T cell recipients have immunosuppression generated by B-cell aplasia leading to a higher susceptibility to respiratory virus infections and poor response to vaccination.

AREAS COVERED

This review focuses on the challenge posed by B-cell targeted immunotherapies: managing long-lasting B-cell impairment during the successive surges of a deadly viral pandemic. We restricted this report to data regarding vaccine efficacy in CAR-T cell recipients, outcomes after developing COVID-19 and specificities of treatment management. We searched in MEDLINE database to identify relevant studies until March 31^st 2022.

EXPERT OPINION

Among available observational studies, the pooled mortality rate reached 40% in CAR-T cell recipients infected by SARS-CoV-2. Additionally, vaccines responses seem to be widely impaired in recipients (seroconversion 20%, T-cell response 50%). In this setting of B-cell depletion, passive immunotherapy is the backbone of treatment. Convalescent plasma therapy has proven to be a highly effective curative treatment with rare adverse events. Neutralizing monoclonal antibodies could be used as pre-exposure prophylaxis or early treatment but their neutralizing activity is constantly challenged by new variants. In order to reduce viral replication, direct-acting antiviral drugs should be considered.

Managing Hypogammaglobulinemia in Patients Treated with CAR-T-cell Therapy: Key Points for Clinicians

INTRODUCTION

The unprecedented success of chimeric antigen receptor (CAR)-T-cell therapy in the management of B-cell malignancies comes with a price of specific side effects. Healthy B-cell depletion is an anticipated 'on-target' 'off-tumor' side effect and can contribute to severe and prolonged hypogammaglobulinemia. Evidence-based guidelines for the use of immunoglobulin replacement therapy (IGRT) for infection prevention are lacking in this population.

AREAS COVERED

This article reviews the mechanisms and epidemiology of hypogammaglobulinemia and antibody deficiency, association with infections, and strategies to address these issues in CD19- and BCMA-CAR-T-cell recipients.

EXPERT OPINION

CD19 and BCMA CAR-T-cell therapy result in unique immune deficits due to depletion of specific B-lineage cells and may require different infection prevention strategies. Hypogammaglobulinemia before and after CAR-T-cell therapy is frequent, but data on the efficacy and cost-effectiveness of IGRT are lacking. Monthly IGRT should be prioritized for patients with severe or recurrent bacterial infections. IGRT may be more broadly necessary to prevent infections in BCMA-CAR-T-cell recipients and children with severe hypogammaglobulinemia irrespective of infection history. Vaccinations are indicated to augment humoral immunity and can be immunogenic despite cytopenias; re-vaccination(s) may be required. Controlled trials are needed to better understand the role of IGRT and vaccines in this population.

Mechanisms of immune effector cell-associated neurotoxicity syndrome after CAR-T treatment

Chimeric antigen receptor T-cell (CAR-T) treatment has revolutionized the landscape of cancer therapy with significant efficacy on hematologic malignancy, especially in relapsed and refractory B cell malignancies. However, unexpected serious toxicities such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) still hamper its broad application. Clinical trials using CAR-T cells targeting specific antigens on tumor cell surface have provided valuable information about the characteristics of ICANS. With unclear mechanism of ICANS after CAR-T treatment, unremitting efforts have been devoted to further exploration. Clinical findings from patients with ICANS strongly indicated existence of overactivated peripheral immune response followed by endothelial activation-induced blood-brain barrier (BBB) dysfunction, which triggers subsequent central nervous system (CNS) inflammation and neurotoxicity. Several animal models have been built but failed to fully replicate the whole spectrum of ICANS in human. Hopefully, novel and powerful technologies like single-cell analysis may help decipher the precise cellular response within CNS from a different perspective when ICANS happens. Moreover, multidisciplinary cooperation among the subjects of immunology, hematology, and neurology will facilitate better understanding about the complex immune interaction between the peripheral, protective barriers, and CNS in ICANS. This review elaborates recent findings about ICANS after CAR-T treatment from bed to bench, and discusses the potential cellular and molecular mechanisms that may promote effective management in the future. This article is categorized under: Cancer > Biomedical Engineering Immune System Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology.

Infectious Complications of CAR T-Cell Therapy Across Novel Antigen Targets in the first 30 days

Infections are a known complication of chimeric antigen receptor (CAR) T-cell therapy with data largely emerging from CD19 CAR T-cell targeting. As CAR T-cell therapy continues to evolve, infection risks and management thereof will become increasingly important to optimize outcomes across the spectrum of antigens and disease targeted. We retrospectively characterized infectious complications occurring in 162 children and adults treated amongst five phase 1 CAR T-cell clinical trials. Trials included targeting of CD19, CD22, disialoganglioside (GD2) or B-cell maturation antigen (BCMA). Fifty-three patients (32.7%) had 76 infections between lymphocyte depleting (LD) chemotherapy and day 30; with the majority (80.5%) occurring between day 0 (D0) and day 30 (D30). By trial, the highest proportion of infections was seen with CD22 CAR T-cells (n=23/53; 43.4%), followed by BCMA CAR T-cells(n=9/24; 37.5%). By disease, patients with multiple myeloma, had the highest proportion of infections (9 of 24, 37.5%) followed by acute lymphoblastic leukemia (36 of 102, 35.3%). Grade 4 infections were rare (n=4, 2.5%). Between D0 and D30, bacteremia and bacterial site infections were the most common infection type. In univariate analysis, increasing prior lines of therapy, recent infection within 100 days of LD chemotherapy, corticosteroid or tocilizumab use and fever and neutropenia (F&N) were associated with a higher risk of infection. In a multivariable analysis, only prior lines of therapy and recent infection were associated with higher risk of infection. In conclusion, we provide a broad overview of infection risk within the first 30 days post infusion across a host of multiple targets and diseases, elucidating both unique characteristics and commonalities highlighting aspects important to improving patient outcomes.

Characteristics and recognition of early infections in patients treated with commercial anti-CD19 CAR-T cells

The characteristics of infections following chimeric antigen receptor T (CAR-T) cells targeting CD19 in real-word population are obscure. We analyzed infections' characteristics in the first month among consecutive patients with diffuse large B-cell lymphoma (DLBCL) (n = 60, median age, 69.3 years), treated with commercial CAR-T cells. ECOG performance status (PS) was 2-3 in most patients (58%). Infections were observed in 45% of patients (16, 27%, bacterial infections, and 14, 23%, viral infections). Bacterial infection included clinically documented infection in 7 (Pneumonia, n = 5; periodontal infection, n = 1; and cellulitis, n = 1) and microbiology documented infection (MDI) in 9 patients (Gram-negative rod, n = 5; Gram-positive cocci, n = 3, bacteremia; polymicrobial, n = 1). The most common viral infection was cytomegalovirus (CMV) reactivation (n = 10, 17%) leading to initiation of anti-CMV treatment in 6 (60%) among these patients. None had CMV disease. In univariate analysis, immune effector cell-associated neurotoxicity syndrome (ICANS) was associated with higher incidence of bacterial infection (OR=4.5, P = .018), while there was a trend for lower incidence of bacterial infections in patients with chemosensitive disease to bridging therapy (OR=0.375, P = .074). Age or PS was not associated with increased risk of bacterial infection. Increase in C-reactive protein (CRP) prior to fever onset was associated with microbiologically documented infections. We conclude that infections are common in the first month following CAR-T-cell administration, however, were not increased in elderly patients or those presenting with poorer PS. Increase in CRP prior to fever onset could support infection over cytokine release syndrome.

[Infectious complications following chimeric antigen receptor T-cell therapy for a hematologic malignancy within 28 days]

Objective: To explore the incidence, clinical and microbiological characteristics and risk factors of infection in patients with acute lymphoblastic (ALL) , non-Hodgkin lymphoma (NHL) , and multiple myeloma (MM) within 28 days after CAR-T cell infusion. It provides data support for early identification of infection and the rational use of antibacterial drugs in these patients. Methods: We retrospectively analyzed the baseline data of 170 patients with ALL, NHL and MM who received chimeric antigen receptor-modified T (CAR-T) -cell treatment in the Department of Hematology of Wuhan Union Hospital from January 2016 to December 2020, and the clinical characteristics of infection within 28 days after infusion, including 72 patients with ALL, 56 patients with NHL, and 42 patients with MM; we used Poisson regression and Cox proportional hazard regression models to assess high-risk factors for infection before and after infusion, respectively. Results: Among 170 patients, 119 infections occurred in 99 patients within 28 days, with a cumulative infection rate of 58.2%. Seventy-eight patients had 98 bacterial infections and the cumulative incidence of bacterial infection was 45.9%. The infection density was 2.01, and the median time for the first infection was about 12 days after infusion. The adjusted baseline characteristic model showed that ALL patients, previous 30 days of infection history, refractory disease, absolute neutrophil count (ANC) <0.5×10(9)/L before infusion and ≥4 prior antitumor treatment regimens had a higher infection density within 28 days; grade 3 or 4 CRS was the only high-risk factor related to infection after infusion in the multivariate analysis. Conclusion: Infection is a common complication of CAR-T cell therapy in patients with hematologic malignancy. Bacterial infections occur in most patients regardless of the type of disease. ALL patients, previous 30 days of infection history, refractory disease, ANC<0.5×10(9)/L before infusion and grade 3 or 4 CRS are risk factors for infection. Chinese Clinical Trial Register:: ChiCTR-OIC-17011180, ChiCTR1800018143.