Blinatumomab Nonresponse and High-Disease Burden Are Associated With Inferior Outcomes After CD19-CAR for B-ALL

Comprehensive analysis of the efficacy and safety of CAR T-cell therapy in patients with relapsed or refractory B-cell acute lymphoblastic leukaemia: a systematic review and meta-analysis

BACKGROUND

Relapse/refractory B-cell acute lymphoblastic leukaemia (r/r B-ALL) represents paediatric cancer with a challenging prognosis. CAR T-cell treatment, considered an advanced treatment, remains controversial due to high relapse rates and adverse events. This study assessed the efficacy and safety of CAR T-cell therapy for r/r B-ALL.

METHODS

The literature search was performed on four databases. Efficacy parameters included minimal residual disease negative complete remission (MRD-CR) and relapse rate (RR). Safety parameters constituted cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS).

RESULTS

Anti-CD22 showed superior efficacy with the highest MRD-CR event rate and lowest RR, compared to anti-CD19. Combining CAR T-cell therapy with haploidentical stem cell transplantation improved RR. Safety-wise, bispecific anti-CD19/22 had the lowest CRS rate, and anti-CD22 showed the fewest ICANS. Analysis of the costimulatory receptors showed that adding CD28ζ to anti-CD19 CAR T-cell demonstrated superior efficacy in reducing relapses with favorable safety profiles.

CONCLUSION

Choosing a more efficacious and safer CAR T-cell treatment is crucial for improving overall survival in acute leukaemia. Beyond the promising anti-CD22 CAR T-cell, exploring costimulatory domains and new CD targets could enhance treatment effectiveness for r/r B-ALL.

Management of ALL in adults: 2024 ELN recommendations from a European expert panel

ABSTRACT

Experts from the European Leukemia Net (ELN) working group for adult acute lymphoblastic leukemia have identified an unmet need for guidance regarding management of adult acute lymphoblastic leukemia (ALL) from diagnosis to aftercare. The group has previously summarized their recommendations regarding diagnostic approaches, prognostic factors, and assessment of ALL. The current recommendation summarizes clinical management. It covers treatment approaches, including the use of new immunotherapies, application of minimal residual disease for treatment decisions, management of specific subgroups, and challenging treatment situations as well as late effects and supportive care. The recommendation provides guidance for physicians caring for adult patients with ALL which has to be complemented by regional expertise preferably provided by national academic study groups.

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.

The new era of immunological treatment, last updated and future consideration of CAR T cell-based drugs

Cancer treatment is one of the fundamental challenges in clinical setting, especially in relapsed/refractory malignancies. The novel immunotherapy-based treatments bring new hope in cancer therapy and achieve various treatment successes. One of the distinguished ways of cancer immunotherapy is adoptive cell therapy, which utilizes genetically modified immune cells against cancer cells. Between different methods in ACT, the chimeric antigen receptor T cells have more investigation and introduced a promising way to treat cancer patients. This technology progressed until it introduced six US Food and Drug Administration-approved CAR T cell-based drugs. These drugs act against hematological malignancies appropriately and achieve exciting results, so they have been utilized widely in cell therapy clinics. In this review, we introduce all CAR T cells-approved drugs based on their last data and investigate them from all aspects of pharmacology, side effects, and compressional. Also, the efficacy of drugs, pre- and post-treatment steps, and expected side effects are introduced, and the challenges and new solutions in CAR T cell therapy are in the last speech.

Intention-to-treat outcomes utilising a stringent event definition in children and young people treated with tisagenlecleucel for r/r ALL through a national access scheme

CAR T-cell therapy has transformed relapsed/refractory (r/r) B-cell precursor acute lymphoblastic leukaemia (B-ALL) management and outcomes, but following CAR T infusion, interventions are often needed. In a UK multicentre study, we retrospectively evaluated tisagenlecleucel outcomes in all eligible patients, analysing overall survival (OS) and event-free survival (EFS) with standard and stringent definitions, the latter including measurable residual disease (MRD) emergence and further anti-leukaemic therapy. Both intention-to-treat and infused cohorts were considered. We collected data on feasibility of delivery, manufacture, toxicity, cause of therapy failure and followed patients until death from any cause. Of 142 eligible patients, 125 received tisagenlecleucel, 115/125 (92%) achieved complete remission (CR/CRi). Severe cytokine release syndrome and neurotoxicity occurred in 16/123 (13%) and 10/123 (8.1%), procedural mortality was 3/126 (2.4%). The 2-year intent to treat OS and EFS were 65.2% (95%CI 57.2-74.2%) and 46.5% (95%CI 37.6-57.6%), 2-year intent to treat stringent EFS was 35.6% (95%CI 28.1-44.9%). Median OS was not reached. Sixty-two responding patients experienced CAR T failure by the stringent event definition. Post failure, 1-year OS and standard EFS were 61.2% (95%CI 49.3-75.8) and 55.3% (95%CI 43.6-70.2). Investigation of CAR T-cell therapy for B-ALL delivered on a country-wide basis, including following patients beyond therapy failure, provides clinicians with robust outcome measures. Previously, outcomes post CAR T-cell therapy failure were under-reported. Our data show that patients can be successfully salvaged in this context with good short-term survival.

Leveraging CD19CAR T cells early in the treatment of older patients with B-ALL: are we there yet?

Older adults (≥55 years old) with B-cell acute lymphoblastic leukemia (B-ALL) have dismal outcomes with standard chemotherapy as the result of low treatment efficacy and considerable risks for treatment-related morbidity and mortality. There has been a recent success with the introduction of novel therapies, such as blinatumomab and inotuzumab, in the frontline therapeutic paradigm in older adults with B-ALL. However, these agents have their own challenges including the limited durability of remission, the need for additional concurrent chemotherapy and the prolonged course of treatment, and limited efficacy in the setting of extramedullary disease. Here, we hypothesize that the incorporation of chimeric antigen receptor (CAR) T cell therapy as a consolidation treatment in older adults with B-cell ALL in their first complete remission is the ideal setting to advance treatment outcomes by reducing treatment toxicity, enhancing remission durability, and expanding the use of this effective therapy in this age population.

Efficacy and Safety of Children With Relapsed/Refractory B-Cell Acute Lymphoblastic Leukemia After Anti-CD19 CAR T-Cell Therapy Without Bridging Transplantation

BACKGROUND

Anti-CD19 chimeric antigen receptor (CAR) T-cell therapies have demonstrated significant efficacy in achieving complete remission (CR) in pediatric patients with relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). However, a considerable number of patients experience relapse within 1 year after CAR T-cell therapy, leading to an extremely poor prognosis, particularly in patients without bridging transplantation.

MATERIALS AND METHODS

In our study, we investigated 42 children with R/R B-ALL who underwent anti-CD19 CAR T-cell therapy without bridging transplantation at our center. All patients were included in the response analysis and evaluated for survival and toxicity.

RESULTS

The cohort that received the CAR T-cell infusion exhibited a 100% CR rate by day 28 (d28). The overall survival (OS) at 4 years was 61.3% ± 8.5%, and the event-free survival (EFS) was 55.9% ± 7.9%, with a median follow-up duration of 50.1 months. Minimal residual disease (MRD) ≥1% was associated with inferior outcomes, resulting in lower 4-year OS (P = .033) and EFS (P = .014) compared to MRD<1%. The incidences of grade ≥3 cytokine release syndrome (CRS) and neurotoxicity were 26.8% and 23.8%, respectively. Furthermore, MRD≥1% was identified as an independent factor associated with increased severity of CRS and occurrence of neurotoxicity.

CONCLUSION

These findings suggest that reducing the pre-infusion MRD could serve as an effective treatment strategy to enhance the outcomes of CAR T-cell therapy.

Optimizing CAR-T cell therapy in adults with B-cell acute lymphoblastic leukemia

Chimeric antigen receptor T-cell (CAR-T) therapy has demonstrated unprecedented success in the treatment of various hematologic malignancies including relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). Currently, there are two FDA-approved CD19-directed CAR-T cell products for the treatment of adults with R/R B-ALL. Despite high remission rates following CD19 CAR-T cell therapy in R/R B-ALL, remission durability remains limited in most adult patients, with relapse observed frequently in the absence of additional consolidation therapy. Furthermore, the burden of CAR-T cell toxicity remains significant in adults with R/R B-ALL and further limits the wide utilization of this effective therapy. In this review, we discuss patient and disease factors that are linked to CAR-T cell therapy outcomes in R/R B-ALL and strategies to optimize durability of response to reduce relapse and mitigate toxicity in the adult population. We additionally discuss future approaches being explored to maximize the benefit of CAR-T in adults with B-ALL.

A bibliometric and knowledge-map analysis of bispecific antibodies in cancer immunotherapy from 2000 to 2023

Background

Bispecific antibody (BsAb)-based cancer immunotherapy has provided new avenues for the treatment of various malignancies. The approval of Blinatumomab has encouraged further investigation into these treatments, and a series of preclinical and clinical trials have been conducted, together with the publication of numerous articles. Here, the knowledge structure of BsAb-based cancer immunotherapy is summarized using bibliometric analysis to provide in-depth insight into current research trends and foci.

Methods

The studies included in the bibliometric analysis of BsAbs in cancer immunotherapy were retrieved from the online Web of Science Core Collection (WOSCC) database on April 16th, 2023. Visualization analysis was performed with the help of CtieSpace (version 6.2.2.msi [64-bit]), VOSviewer (version 1.6.19), R (version 4.2.1), and the Bibliometric analysis platform (R-based online data processing tool).

Results

A total of 1750 papers were identified. Analysis of annual publications and total citations indicated that publications have increased steadily over the past few decades. The USA, followed by Germany, had largest number of publications, making significant contributions to the field. The Memorial Sloan Kettering Cancer Center received the highest number of citations (n = 3769). However, its collaboration and cooperation with different institutions require further strengthening. MAbs and Clinical Cancer Research published the most papers, while Blood and Cancer Research were the most commonly co-cited journals. DM Goldenberg from the USA published the most articles with the highest H-index (34), and the most co-cited author (2137 citations) was PA Baeuerle; both these authors have distinguished achievements in this field. Analysis of co-cited references and keywords showed that the hotspots and research focus on the use of BsAbs for solid tumors have increased rapidly while the application of BsAb immunotherapy in hematologic malignancies has expanded significantly. The hot topics in the field included cytokine release syndrome, the efficacy and safety of BsAbs, resistance mechanisms, and the exploration and optimization of combination therapies.

Conclusion

Cancer immunotherapies based on BsAbs are a hot topic in research. Current studies focus on the construction and optimization of BsAb structure, as well as their combination with other treatment modalities to improve their efficacy and overcome resistance. Furthermore, it is expected that the ongoing investigation of BsAb-based immunotherapy for solid tumors will bear fruit with significant clinical application prospects in the near future.

Impact of disease burden and late loss of B cell aplasia on the risk of relapse after CD19 chimeric antigen receptor T Cell (Tisagenlecleucel) infusion in pediatric and young adult patients with relapse/refractory acute lymphoblastic leukemia: role of B-cell monitoring

Introduction

Loss of B-cell aplasia (BCA) is a well-known marker of functional loss of CD19 CAR-T. Most relapses and loss of BCA occur in the first months after CD19 CAR-T infusion. In addition, high tumor burden (HTB) has shown to have a strong impact on relapse, especially in CD19-negative. However, little is known about the impact of late loss of BCA or the relationship between BCA and pre-infusion tumor burden in patients infused with tisagenlecleucel for relapsed/refractory B-cell acute lymphoblastic leukemia. Therefore, the optimal management of patients with loss of BCA is yet to be defined.

Methods

We conducted a Spanish, multicentre, retrospective study in patients infused with tisagenlecleucel after marketing authorization. A total of 73 consecutively treated patients were evaluated.

Results

Prior to infusion, 39 patients had HTB (≥ 5% bone marrow blasts) whereas 34 had a low tumor burden (LTB) (<5% blasts). Complete remission was achieved in 90.4% of patients, of whom 59% relapsed. HTB was associated with inferior outcomes, with a 12-month EFS of 19.3% compared to 67.2% in patients with LTB (p<0.001) with a median follow-up of 13.5 months (95% CI 12.4 - 16.2). In the HTB subgroup relapses were mainly CD19-negative (72%) whereas in the LTB subgroup they were mainly CD19-positive (71%) (p=0.017). In the LTB group, all CD19-positive relapses were preceded by loss of BCA whereas only 57% (4/7) of HTB patients experienced CD19-positive relapse. We found a positive correlation between loss of BCA and CD19-positive relapse (R-squared: 74) which persisted beyond six months post-infusion. We also explored B-cell recovery over time using two different definitions of loss of BCA and found a few discrepancies. Interestingly, transient immature B-cell recovery followed by BCA was observed in two pediatric patients. In conclusion, HTB has an unfavorable impact on EFS and allo-SCT might be considered in all patients with HTB, regardless of BCA. In patients with LTB, loss of BCA preceded all CD19-positive relapses. CD19-positive relapse was also frequent in patients who lost BCA beyond six months post-infusion. Therefore, these patients are still at significant risk for relapse and close MRD monitoring and/or therapeutic interventions should be considered.

Emerging Biomarkers for Monitoring Chimeric Antigen Receptor T-Cell Therapy

BACKGROUND

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized treatment of hematologic malignancies and holds promise for solid tumors. While responses to CAR T-cell therapy have surpassed other available options for patients with refractory malignancies, not all patients respond the same way. The reason for this variability is not currently understood. Therefore, there is a strong need to identify characteristics of patients as well as cellular products that lead to an effective response to CAR T-cell therapy.

CONTENT

In this review, we discuss potential biomarkers that may predict clinical outcomes of CAR T-cell therapy. Based on correlative findings from clinical trials of both commercially available and early-phase products, we classify biomarkers into categories of pre- and post-infusion as well as patient and product-related markers. Among the biomarkers that have been explored, measures of disease burden both pre- and post-infusion, as well as CAR T-cell persistence post-infusion, are repeatedly identified as predictors of disease response. Higher proportions of early memory T cells at infusion appear to be favorable, and tracking T-cell subsets throughout treatment will likely be critical.

SUMMARY

There are a growing number of promising biomarkers of CAR T-cell efficacy described in the research setting, however, none of these have been validated for clinical use. Some potentially important predictors of response may be difficult to obtain routinely under the current CAR T-cell therapy workflow. A collaborative approach is needed to select biomarkers that can be validated in large cohorts and incorporated into clinical practice.

Determinants of outcomes and advances in CD19-directed chimeric antigen receptor therapy for B-cell acute lymphoblastic leukemia

Relapsed and refractory B-cell acute lymphoblastic leukemia (B-ALL) is an aggressive B-cell neoplasm associated with poor outcomes. Conventional multiagent chemotherapy and bispecific antibody therapy may induce remission; however, relapse rates remain high and overall survival is poor. Chimeric antigen receptor T-cell (CAR-T) therapy provides durable, deep complete remission, and long-term cures in relapsed and refractory B-ALL. However, with this new treatment modality, 10%-30% of patients do not achieve remission, and over 50% experience relapse after therapy. Currently, there are two approved CD19-specific CAR-T cell constructs in B-ALL, Tisagenlecleucel and Brexucabtagene Autoleucel by the United States Food and Drug Administration, and the European Medicines Agency (EMA). In this review, we discuss patients, disease, and CAR-T predictors of outcomes in B-ALL. We describe the two approved CD19-directed CAR-T cell products, review the current literature, and discuss factors associated with high risks of therapy failure and future direction in CAR-T cell therapy for B-ALL.

CAR-T Cell Therapy in B-Cell Acute Lymphoblastic Leukemia

Treatment of refractory and relapsed (R/R) B acute lymphoblastic leukemia (B-ALL) is an unmet medical need in both children and adults. Studies carried out in the last two decades have shown that autologous T cells engineered to express a chimeric antigen receptor (CAR-T) represent an effective technique for treating these patients. Antigens expressed on B-cells, such as CD19, CD20, and CD22, represent targets suitable for treating patients with R/R B-ALL. CD19 CAR-T cells induce a high rate (80-90%) of complete remissions in both pediatric and adult R/R B-ALL patients. However, despite this impressive rate of responses, about half of responding patients relapse within 1-2 years after CAR-T cell therapy. Allo-HSCT after CAR-T cell therapy might consolidate the therapeutic efficacy of CAR-T and increase long-term outcomes; however, not all the studies that have adopted allo-HSCT as a consolidative treatment strategy have shown a benefit deriving from transplantation. For B-ALL patients who relapse early after allo-HSCT or those with insufficient T-cell numbers for an autologous approach, using T cells from the original stem cell donor offers the opportunity for the successful generation of CAR-T cells and for an effective therapeutic approach. Finally, recent studies have introduced allogeneic CAR-T cells generated from healthy donors or unmatched, which are opportunely manipulated with gene editing to reduce the risk of immunological incompatibility, with promising therapeutic effects.

INSPIRED Symposium Part 4A: Access to CAR T Cell Therapy in Unique Populations with B Cell Acute Lymphoblastic Leukemia

The approval of tisagenlecleucel (tisa-cel) for use in children with B cell acute lymphoblastic leukemia (B-ALL) was based on the phase 2 ELIANA trial, a global registration study. However, the ELIANA trial excluded specific subsets of patients facing unique challenges and did not include a sufficient number of patients to adequately evaluate outcomes in rare subpopulations. Since the commercialization of tisa-cel, data have become available that support therapeutic indications beyond the specific cohorts previously eligible for chimeric antigen receptor (CAR) T cells targeted to CD19 (CD19 CAR-T) therapy on the registration clinical trial. Substantial real-world data and aggregate clinical trial data have addressed gaps in our understanding of response rates, longer-term efficacy, and toxicities associated with CD19 CAR-T in special populations and rare clinical scenarios. These include patients with central nervous system relapsed disease, who were excluded from ELIANA and other early CAR-T trials owing to concerns about risk of neurotoxicity that have not been born out. There is also interest in the use of CD19 CAR-T for very-high-risk patients earlier in the course of therapy, such as patients with persistent minimal residual disease after 2 cycles of upfront chemotherapy and patients with first relapse of B-ALL. However, these indications are not specified on the label for tisa-cel and historically were not included in eligibility criteria for most clinical trials; data addressing these populations are needed. Populations at high risk of relapse, including patients with high-risk cytogenetic lesions, infants with B-ALL, patients with trisomy 21, and young adults with B-ALL, also may benefit from earlier treatment with CD19 CAR-T. It is important to prospectively study patient-reported outcomes given the differential toxicity expected between CD19 CAR-T and the historic standard of care, hematopoietic cell transplantation. Now that CD19 CAR-T therapy is commercially available, studies evaluating potential access disparities created by this very expensive novel therapy are increasingly pressing.

Comparison of blinatumomab and CAR T-cell therapy in relapsed/refractory acute lymphoblastic leukemia: a systematic review and meta-analysis

OBJECTIVES

This study evaluated the benefits and risks of patients with refractory or relapsed acute lymphocytic leukemia (R/R ALL) treated with anti-CD19 chimeric antigen receptor (CAR) T-cell therapy and blinatumomab.

METHODS

PubMed, Web of Science, Embase, and the Cochrane Library were searched for relevant studies.

RESULTS

The pooled complete remission (CR) rate and minimal residual disease (MRD) negative rate were 48%, 31% for blinatumomab, and 86% and 80% for CAR T-cell therapy.

CONCLUSIONS

The CAR T-cell therapy group exhibited a higher likelihood of CR rate than the blinatumomab group in every analysis regardless of adjustment subgroups. CAR T-cell therapy was associated with a significantly prolonged overall survival (OS) and relapse-free survival (RFS) compared with blinatumomab (2-year OS 55% vs 25%; 2-year RFS 40% vs 22%). CAR T-cell therapy was more effective for achieving CR and bridging to allogeneic hematopoietic stem cell transplantation (allo-SCT) than blinatumomab (2-year OS 75% vs. 57%). An emerging role for blinatumomab is as a bridging agent pre-SCT, and for patients who achieve an MRD-negative state pre-SCT, post-SCT outcomes are expected to be the same as CAR-T. For adverse effects (AEs), blinatumomab was associated with a lower rate of grade ≥3 hematological toxicity, CRS, and neurological events.

Practice Preferences for Consolidative Hematopoietic Stem Cell Transplantation Following Tisagenlecleucel in Children and Young Adults with B Cell Acute Lymphoblastic Leukemia

Treatment with tisagenlecleucel (tisa-cel) achieves excellent complete remission rates in children and young adults with relapsed or refractory B cell acute lymphoblastic leukemia (B-ALL), but approximately 50% maintain long-term remission. Consolidative hematopoietic stem cell transplantation (cHSCT) is a potential strategy to reduce relapse risk, but it carries substantial short- and long-term toxicities. Additionally, several strategies for management of B cell recovery (BCR) and next-generation sequencing (NGS) positivity post-tisa-cel exist, without an accepted standard. We hypothesized that practice preferences surrounding cHSCT, as well as management of BCR and NGS positivity, varies across tisa-cel-prescribing physicians and sought to characterize current practice preferences. A survey focusing on preferences regarding the use of cHSCT, management of BCR, and NGS positivity was distributed to physicians who prescribe tisa-cel for children and young adults with B-ALL. Responses were collected from August 2022 to April 2023. Fifty-nine unique responses were collected across 43 institutions. All respondents prescribed tisa-cel for children and young adults. The clinical focus of respondents was HSCT in 71%, followed by leukemia/lymphoma in 24%. For HSCT-naive patients receiving tisa-cel, 57% of respondents indicated they made individualized decisions for cHSCT based on patient factors, whereas 22% indicated they would avoid cHSCT and 21% indicated they would pursue cHSCT when feasible. Certain factors influenced >50% of respondents towards recommending cHSCT (either an increased likelihood of recommending or always recommending), including preinfusion disease burden >25%, primary refractory B-ALL, M3 bone marrow following reinduction for relapse, KMT2A-rearranged B-ALL, history of blinatumomab nonresponse, and HSCT-naive status. Most respondents indicated they would pursue HSCT for HSCT-naive, total body irradiation (TBI) recipients with BCR before 6 months post-tisa-cel or with NGS positivity at 1 or 3 months post-tisa-cel, although there was variability in responses regarding whether to proceed to HSCT directly or provide intervening therapy prior to HSCT. Fewer respondents recommended HSCT for BCR or NGS positivity in patients with a history of HSCT, in noncandidates for TBI, and in patients with trisomy 21. The results of this survey indicate there exists significant practice variability regarding the use of cHSCT, as well as interventions for post-tisa-cel BCR or NGS positivity. These results highlight areas in which ongoing clinical trials could inform more standardized practice.

Cerebral Spinal Fluid Parameters Following CD19-Targeted Therapies in Children and Young Adults

The presence of leukocytes in the cerebral spinal fluid (CSF) of patients with acute lymphoblastic leukemia may indicate a relapse in the central nervous system. CD19-directed immunotherapy may increase the blood-brain barrier permeability, leading to neurologic toxicity and infiltrate the CNS. We studied the CSF cell and protein content in 71 consecutive patients who received either CD19 chimeric antigen receptor T cells or blinatumomab. Responding patients had an incidence of 66% and 61% of pleocytosis following blinatumomab or chimeric antigen receptor T cells, respectively. CSF parameters did not correlate with toxicity or prior CNS disease. Routine CSF flow cytometry following immunotherapy to distinguish T-cell infiltration from CNS relapse should be considered.

Preventing relapse after CD19 CAR T-cell therapy for pediatric ALL: the role of transplant and enhanced CAR T cells

CD19-specific chimeric antigen receptor (CAR) T-cell therapy has become an integral part of our treatment armamentarium for pediatric patients with relapsed or refractory B-cell acute lymphoblastic leukemia (B-ALL). However, despite initial remission rates of greater than 80%, durable remission occurs in only 40% to 50% of patients. In this review we summarize our current knowledge of the role of consolidative hematopoietic cell transplantation in the management of pediatric patients who achieved a minimal residual disease-negative complete response post CD19 CAR T-cell therapy. In addition, we review approaches to enhance effector function CD19 CAR T cells, focusing on how to improve persistence and prevent the emergence of CD19- B-ALL blasts.

Chimeric Antigen Receptor T-Cell Therapy in Aggressive B-Cell Lymphoma

Chimeric antigen receptor (CAR) T-cell therapy is a revolutionary therapy increasingly used in the treatment of non-Hodgkin B-cell lymphoma. This review focuses on the use of CAR T-cell therapy in aggressive B-cell lymphoma including clinical indications, known short- and long-term toxicity, mechanisms of CAR T-cell efficacy and tumor resistance, and future directions in the treatment of aggressive lymphoma with CAR T-cell therapy.

The Current State of Chimeric Antigen Receptor T Cell Therapy for B Lymphoblastic Leukemia

Over the past decade, CAR T cell therapy has transformed the treatment of relapsed or refractory B-ALL in children and adults. CD19-directed CAR T cells can induce complete remissions in a large majority of patients with B-ALL, and up to half of these patients will go on to maintain durable remissions. However, significant challenges remain for patients who relapse or do not respond. This review will discuss the history of CAR T cell therapy for B-ALL, the treatment considerations for CAR T cell recipients, and current clinical trials and future directions for CAR T cell therapy in B-ALL.

Bone marrow fibrosis is associated with non-response to CD19 CAR T-cell therapy in B-acute lymphoblastic leukemia

CD19 directed CAR T-cell therapy is used to treat relapsed/refractory B-cell acute lymphoblastic leukemia. The role of the pre-CAR bone marrow (BM) stromal microenvironment in determining response to CAR T-cell therapy has been understudied. We performed whole transcriptome analysis, reticulin fibrosis assessment and CD3 T-cell infiltration on BM core biopsies from pre- and post-CAR timepoints for 61 patients, as well as on a cohort of 54 primary B-ALL samples. Pathways of fibrosis, extracellular matrix development, and associated transcription factors AP1 and TGF-β3, were enriched and upregulated in nonresponders (NR) even prior to CAR T cell therapy. NR showed significantly higher levels of BM fibrosis compared to complete responders by both clinical reticulin assessment and AI-assisted digital image scoring. CD3+ T cells showed a trend toward lower infiltration in NR. NR had significantly higher levels of pre-CAR fibrosis compared to primary B-ALL. High levels of fibrosis were associated with lower overall survival after CAR T-cell therapy. In conclusion, BM fibrosis is a novel mechanism mediating nonresponse to CD19-directed CAR T-cell therapy in B-ALL. A widely used clinically assay for quantitating myelofibrosis can be repurposed to determine patients at high risk of non-response. Genes and pathways associated with BM fibrosis are a potential target to improve response.

Early and Late Toxicities of Chimeric Antigen Receptor T-Cells

As chimeric antigen receptor (CAR) T-cell therapy is increasingly integrated into clinical practice across a range of malignancies, identifying and treating inflammatory toxicities will be vital to success. Early experiences with CD19-targeted CAR T-cell therapy identified cytokine release syndrome and neurotoxicity as key acute toxicities and led to unified initiatives to mitigate the influence of these complications. In this section, we provide an update on the current state of CAR T-cell-related toxicities, with an emphasis on emerging acute toxicities affecting additional organ systems and considerations for delayed toxicities and late effects.

Chimeric Antigen Receptor T Cell Therapy for Acute Leukemia

The worldwide use of CD19 chimeric antigen receptor (CAR)-T cells has increased the response rate in patients with refractory or relapsed B-cell acute lymphoblastic leukemia. Clinical practice has become much safer with the help of immunotherapy-related toxicity management guidelines, such as the ASTCT consensus grading system. Tocilizumab and steroids are the major interventions for controlling cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). New drugs and interventions for uncontrolled CRS and ICANS, including JAK1/2 inhibitors, have also been investigated. The combination of ruxolitinib and steroids effectively controlled severe CRS without impeding CAR-T cell expansion. Patients with refractory CNS3 status and CNS masses were excluded from the clinical trials because of the high risk of severe ICANS. Intracranial injections of steroids and Ommaya capsule implantation were effective. For some heavily treated patients, the difficulties in CAR-T cell manufacturing and expansion may be resolved by combination with blinatumumab. Relapse is a major concern after CAR-T therapy, and combination interventions, such as allogeneic stem cell transplantation, dual-target CAR-T cell therapies, and sequential CD19/22 CAR-T infusion, have been investigated in many centers. For T-lineage-targeted CAR-T therapies, the CAR T-cell fratricide can be overcome using many techniques. The efficacy and safety of CD7+ CAR-T cell therapy have been widely reported in recent years. A high response rate can be achieved when the immune reconstitution is prolonged. Infections, particularly viral reactivations, should be carefully monitored, as relapses are another potential issue. Switching targets and eliminating residual CD7+ CAR-T cells in the blood are key points for patients who relapse after CD7+ CAR-T cell therapy. CAR-T cell therapies for AML have not been investigated in a large-scale cohort, except for CD19-positive AML with the AML1-ETO fusion gene.

Sequential CD19 and CD22 chimeric antigen receptor T-cell therapy for childhood refractory or relapsed B-cell acute lymphocytic leukaemia: a single-arm, phase 2 study

BACKGROUND

Relapses frequently occur following CD19-directed chimeric antigen receptor (CAR) T-cell treatment for relapsed or refractory B-cell acute lymphocytic leukaemia in children. We aimed to assess the activity and safety of sequential CD19-directed and CD22-directed CAR T-cell treatments.

METHODS

This single-centre, single-arm, phase 2 trial, done at Beijing GoBroad Boren Hospital, Beijing, China, included patients aged 1-18 years who had relapsed or refractory B-cell acute lymphocytic leukaemia with CD19 and CD22 positivity greater than 95% and an Eastern Cooperative Oncology Group performance status of 0-2. Patients were initially infused with CD19-directed CAR T cells intravenously, followed by CD22-directed CAR T-cell infusion after minimal residual disease-negative complete remission (or complete remission with incomplete haematological recovery) was reached and all adverse events (except haematological adverse events) were grade 2 or better. The target dose for each infusion was 0·5 × 106 to 5·0 × 106 cells per kg. The primary endpoint was objective response rate at 3 months after the first infusion. Secondary endpoints were duration of remission, event-free survival, disease-free survival, overall survival, safety, pharmacokinetics, and B-cell quantification. The prespecified activity analysis included patients who received the target dose and the safety analysis included all treated patients. This study is registered with ClinicalTrials.gov, NCT04340154, and enrolment has ended.

FINDINGS

Between May 28, 2020, and Aug 16, 2022, 81 participants were enrolled, of whom 31 (38%) were female and 50 (62%) were male. Median age was 8 years (IQR 6-10), all patients were Asian. All 81 patients received the first infusion and 79 (98%) patients received sequential infusions, CD19-directed CAR T cells at a median dose of 2·7 × 106 per kg (IQR 1·1 × 106 to 3·7 × 106) and CD22-directed CAR T cells at a median dose of 2·2 × 106 per kg (1·1 × 106 to 3·7 × 106), with a median interval of 39 days (37-41) between the two infusions. 62 (77%) patients received the target dose, including two patients who did not receive CD22 CAR T cells. At 3 months, 60 (97%, 95% CI 89-100) of the 62 patients who received the target dose had an objective response. Median follow-up was 17·7 months (IQR 11·4-20·9). 18-month event-free survival for patients who received the target dose was 79% (95% CI 66-91), duration of remission was 80% (68-92), and disease-free survival was 80% (68-92) with transplantation censoring; overall survival was 96% (91-100). Common adverse events of grade 3 or 4 between CD19-directed CAR T-cell infusion and 30 days after CD22-directed CAR T-cell infusion included cytopenias (64 [79%] of 81 patients), cytokine release syndrome (15 [19%]), neurotoxicity (four [5%]), and infections (five [6%]). Non-haematological adverse events of grade 3 or worse more than 30 days after CD22-directed CAR T-cell infusion occurred in six (8%) of 79 patients. No treatment-related deaths occurred. CAR T-cell expansion was observed in all patients, with a median peak at 9 days (IQR 7-14) after CD19-directed and 12 days (10-15) after CD22-directed CAR T-cell infusion. At data cutoff, 35 (45%) of 77 evaluable patients had CAR transgenes and 59 (77%) had B-cell aplasia.

INTERPRETATION

This sequential strategy induced deep and sustained responses with an acceptable toxicity profile, and thus potentially provides long-term benefits for children with this condition.

FUNDING

The National Key Research & Development Program of China, the CAMS Innovation Fund for Medical Sciences (CIFMS), and the Non-Profit Central Research Institute Fund of Chinese Academy of Medical Sciences.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Tisagenlecleucel utilisation and outcomes across refractory, first relapse and multiply relapsed B-cell acute lymphoblastic leukemia: a retrospective analysis of real-world patterns

Background

Tisagenlecleucel was approved by the Food and Drug Administration (FDA) in 2017 for refractory B-cell acute lymphoblastic leukemia (B-ALL) and B-ALL in ≥2nd relapse. Outcomes of patients receiving commercial tisagenlecleucel upon 1st relapse have yet to be established. We aimed to report real-world tisagenlecleucel utilisation patterns and outcomes across indications, specifically including patients treated in 1st relapse, an indication omitted from formal FDA approval.

Methods

We conducted a retrospective analysis of real-world tisagenlecleucel utilisation patterns across 185 children and young adults treated between August 30, 2017 and March 6, 2020 from centres participating in the Pediatric Real-World CAR Consortium (PRWCC), within the United States. We described definitions of refractory B-ALL used in the real-world setting and categorised patients by reported Chimeric Antigen Receptor (CAR) T-cell indication, including refractory, 1st relapse and ≥2nd relapse B-ALL. We analysed baseline patient characteristics and post-tisagenlecleucel outcomes across defined cohorts.

Findings

Thirty-six percent (n = 67) of our cohort received tisagenlecleucel following 1st relapse. Of 66 evaluable patients, 56 (85%, 95% CI 74-92%) achieved morphologic complete response. Overall-survival (OS) and event-free survival (EFS) at 1-year were 69%, (95% CI 58-82%) and 49%, (95% CI 37-64%), respectively, with survival outcomes statistically comparable to remaining patients (OS; p = 0.14, EFS; p = 0.39). Notably, toxicity was increased in this cohort, warranting further study. Interestingly, of 30 patients treated for upfront refractory disease, 23 (77%, 95% CI 58-90%) had flow cytometry and/or next-generation sequencing (NGS) minimum residual disease (MRD)-only disease at the end of induction, not meeting the historic morphologic definition of refractory.

Interpretation

Our findings suggested that tisagenlecleucel response and survival rates overlap across patients treated with upfront refractory B-ALL, B-ALL ≥2nd relapse and B-ALL in 1st relapse. We additionally highlighted that definitions of refractory B-ALL are evolving beyond morphologic measures of residual disease.

Funding

St. Baldrick's/Stand Up 2 Cancer, Parker Institute for Cancer Immunotherapy, Virginia and D.K. Ludwig Fund for Cancer Research.

Identification of potential therapeutic drugs targeting core genes for systemic lupus erythematosus (SLE) and coexisting COVID-19: Insights from bioinformatic analyses

OBJECTIVE

Systemic lupus erythematosus (SLE) patients are at risk during the COVID-19 pandemic, yet the underlying molecular mechanisms remain incompletely understood. This study sought to analyze the potential molecular connections between COVID-19 and SLE, employing a bioinformatics approach to identify effective drugs for both conditions.

METHODS

The data sets GSE100163 and GSE183071 were utilized to determine share differentially expressed genes (DEGs). These DEGs were later analyzed by various bioinformatic methods, including functional enrichment, protein-protein interaction (PPI) network analysis, regulatory network construction, and gene-drug interaction construction.

RESULTS

A total of 50 common DEGs were found between COVID-19 and SLE. Gene ontology (GO) functional annotation revealed that "immune response," "innate immune response," "plasma membrane," and "protein binding" were most enriched in. Additionally, the pathways that were enriched include "Th1 and Th2 cell differentiation." The study identified 48 genes/nodes enriched with 292 edges in the PPI network, of which the top 10 hub genes were CD4, IL7R, CD3E, CD5, CD247, KLRB1, CD40LG, CD7, CR2, and GZMK. Furthermore, the study found 48 transcription factors and 8 microRNAs regulating these hub genes. Finally, four drugs namely ibalizumab (targeted to CD4), blinatumomab (targeted to CD3E), muromonab-CD3 (targeted to CD3E), and catumaxomab (targeted to CD3E) were found in gene-drug interaction.

CONCLUSION

Four possible drugs that targeted two specific genes, which may be beneficial for COVID-19 patients with SLE.

CAR T-Cells for the Treatment of B-Cell Acute Lymphoblastic Leukemia

B-cell acute lymphoblastic leukemia (B-ALL) is the most common subtype of acute leukemia in the pediatric population. The prognosis and treatment of B-ALL have dramatically improved over the past decade with the adoption of intensive and prolonged combination chemotherapy regimens. The advent of novel immunologic agents such as blinatumomab and inotuzumab has changed the treatment landscape of B-ALL. However, patients have continued to relapse, raising the need for novel therapies. Chimeric antigen receptor (CAR) T-cells have achieved a milestone in the treatment of B-ALL. Two CD19-targeting CAR T-cells were approved by the Food and Drug Administration and the European Medicines Agency for the treatment of relapsed and/or refractory B-ALL. In this review, we review the available data regarding CD19-targeting CAR T-cells with their safety profile as well as the mechanism of resistance to these agents and the way to overcome this resistance.

Survival outcomes in patients with relapsed/refractory or MRD-positive B-cell acute lymphoblastic leukemia treated with blinatumomab

Blinatumomab has demonstrated significant efficacy in adult and pediatric patients with relapsed/refractory B-cell acute lymphoblastic leukemia (R/R B-cell ALL) and patients with measurable residual disease (MRD). This review aimed to compare median relapse-free survival (RFS) and median overall survival (OS) in adult and pediatric patients with R/R or MRD-positive B-cell ALL from pivotal studies [MT-103-211 and TOWER for adults with Philadelphia chromosome (Ph)-negative R/R B-cell ALL, ALCANTARA for adults with Ph-positive R/R B-cell ALL, MT-103-203 for adults with MRD-positive B-cell ALL, and MT-103-205 for pediatric patients with R/R B-cell ALL], with the median RFS and OS from retrospective analyses, country or ethnicity-specific studies, and studies based on real-world evidence (RWE) identified from a literature search. Adults with Ph-negative R/R B-cell ALL who received blinatumomab as first salvage demonstrated a numerically longer median OS compared with that in patients from pivotal studies (MT-103-211 and TOWER) without additional safety concerns. In pediatric patients with R/R B-cell ALL treated with blinatumomab, the median RFS and OS from retrospective analyses and country/ethnicity-specific studies were comparable with the median RFS and OS from the pivotal study MT-103-205. The median RFS and OS from RWE studies in adults with R/R B-cell ALL were numerically longer than the median RFS and OS from pivotal studies (MT-103-211, TOWER, and ALCANTARA); however, this trend was not observed in pediatric patients with R/R B-cell ALL. In conclusion, this analysis identified first salvage adults with Ph-negative R/R B-cell ALL as particularly well-suited for treatment with blinatumomab since survival outcomes from retrospective analyses reported in this patient subgroup were numerically better compared with those from pivotal studies without additional safety signals.

Incidence of CD19-negative relapse after CD19-targeted immunotherapy in R/R BCP acute lymphoblastic leukemia: a review

There are inconsistencies in the reporting of CD19 antigen status following treatment with CD19-targeted therapies. A majority of evidence comes from studies reporting small sample sizes. In this review, we systematically summarize published studies that have reported rates of CD19-negative relapse after treatment with either blinatumomab or CD19-directed CAR T-cell therapy and report the rates of CD19-negative relapse when evaluated in a standardized way across trials. CD19-negative relapse appears to occur more commonly in relapses following CAR T-cell therapy compared with blinatumomab, whether proportions are calculated among all treated patients (8.7% vs 4.5%) or among patients who relapse (30% vs 22.5%). The median (range) duration of follow-up was 29.3 (17.4-50.8) and 20.4 (6.9-49.0) months for publications on blinatumomab (n = 10) and CAR T-cell therapies (n = 23), respectively. There is a need for standardized reporting of CD19 antigen status in the setting of relapse following novel immunotherapies to inform clinical practice.

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.

Chimeric Antigen Receptor T-Cell Therapy for Hematologic Malignancies: A Practical Review

Chimeric antigen receptor T-cell (CAR-T) therapy has become an established therapeutic approach for the treatment of hematologic malignancies. The field continues to evolve rapidly and newer-generation constructs are being designed to enhance proliferative capacity, and achieve long-term persistence and greater efficacy with an overall lower incidence of toxicity. Initial clinical application of CAR-T therapies has focused on relapsed and/or refractory hematologic malignancies, and Food and Drug Administration-approved CAR-T products targeting CD19 are available for B-cell acute lymphoblastic leukemia and low- and high-grade B-cell non-Hodgkin lymphoma, and targeting B-cell maturation antigen are available for multiple myeloma. Cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome have been recognized as class specific toxicities associated with these novel therapies. In this review, we focus on the clinical application of CAR-T therapies in adult patients with hematologic malignancies, including access issues, outpatient administration, and appropriate timing for referring a patient to a CAR-T treatment center.

A Novel bispecific T-cell engager (BiTE) targeting CD22 and CD3 has both in vitro and in vivo activity and synergizes with blinatumomab in an acute lymphoblastic leukemia (ALL) tumor model

Immunotherapy has revolutionized cancer therapy. Two recently FDA-approved immunotherapies for B-cell malignancies target CD19, in the form of a Bispecific T-Cell Engager (BiTE) antibody construct or chimeric antigen receptor T (CAR-T) cells. Blinatumomab, an FDA-approved BiTE, binds to CD19 on B cells and to CD3 on T cells, mediating effector-target cell contact and T-cell activation that results in effective elimination of target B cells. Although CD19 is expressed by essentially all B-cell malignancies at clinical presentation, relapses with loss or reduction in CD19 surface expression are increasingly recognized as a cause of treatment failure. Therefore, there is a clear need to develop therapeutics for alternate targets. We have developed a novel BiTE consisting of humanized anti-CD22 and anti-CD3 single chain variable fragments. Target binding of the anti-CD22 and anti-CD3 moieties was confirmed by flow cytometry. CD22-BiTE promoted in vitro cell-mediated cytotoxicity in a dose and effector: target (E:T)-dependent fashion. Additionally, in an established acute lymphoblastic leukemia (ALL) xenograft mouse model, CD22-BiTE demonstrated tumor growth inhibition, comparable to blinatumomab. Further, the combination of blinatumomab and CD22-BiTE yielded increased efficacy in vivo when compared to the single agents. In conclusion, we report here the development of a new BiTE with cytotoxic activity against CD22+ cells which could represent an alternate or complementary therapeutic option for B-cell malignancies.

Chimeric Antigen Receptor T Cells as Salvage Therapy for Post-Chimeric Antigen Receptor T Cell Failure

Outcomes for post-chimeric antigen receptor (CAR) T cell therapy (CART) relapse are poor. The utilization of a unique CAR T cell construct for post-CART failure is increasing, but this approach is not well described. In this study, with CART-A the first unique CAR T cell construct received and CART-B the second, the primary objective was to characterize outcomes following CART-B. Secondary objectives included evaluating safety and toxicity with sequential CART infusions; investigating the impact of potential factors, such as antigen modulation and interval therapy, on CART-B response; and characterizing long-term outcomes in patients receiving multiple CARTs. This was a retrospective review (NCT03827343) of children and young adults with B cell acute lymphoblastic leukemia (B-ALL) undergoing CART therapy who received at least 2 unique CART constructs, excluding interim CART reinfusions of the same product. Of 135 patients, 61 (45.1%) received 2 unique CART constructs, including 13 who received >2 CARTs over time. Patients included in this analysis received 14 distinct CARTs targeting CD19 and/or CD22. The median age at CART-A was 12.6 years (range, 3.3 to 30.4 years). The median time from CART-A to CART-B was 302 days (range, 53 to 1183 days). CART-B targeted a different antigen than CART-A in 48 patients (78.7%), owing primarily to loss of CART-A antigen target. The rate of complete remission (CR) was lower with CART-B (65.5%; 40 of 61) than with CART-A (88.5%; 54 of 61; P = .0043); 35 of 40 (87.5%) CART-B responders had CART-B targeting a different antigen than CART-A. Among the 21 patients with a partial response or nonresponse to CART-B, 8 (38.1%) received CART-B with the same antigen target as CART-A. Of 40 patients with CART-B complete response (CR), 29 (72.5%) relapsed. For the 21 patients with evaluable data, the relapse immunophenotype was antigennegative in 3 (14.3%), antigendim in 7 (33.3%), antigenpositive in 10 (47.6%), and lineage switch in 1 (4.8%). The median relapse-free survival following CART-B CR was 9.4 months (95% confidence interval [CI], 6.1 to 13.2 months), and overall survival was 15.0 months (95% CI, 13.0 to 22.7 months). Given the limited salvage options for post-CART relapse, identifying optimizing strategies for CART-B is critical. We raise awareness about the emerging use of CART for post-CART failure and highlight clinical implications accompanying this paradigm shift.

Inotuzumab ozogamicin in B-cell precursor acute lymphoblastic leukemia: efficacy, toxicity, and practical considerations

Inotuzumab ozogamicin (InO) is an antibody drug conjugate composed of a humanized monoclonal antibody targeting the cell surface receptor CD22 coupled to a cytotoxic calicheamicin payload via an acid labile linker. InO has shown significant activity in relapsed and refractory B-cell precursor acute lymphoblastic leukemia (BCP-ALL) in both single agent and combination chemotherapy regimens in adult and pediatric trials. Its use in newly diagnosed elderly patients has also been established while clinical trials investigating its use in newly diagnosed pediatric patients and fit adults are ongoing. Notable toxicities include sinusoidal obstruction syndrome (SOS), particularly in patients who undergo hematopoietic stem cell transplantation (HSCT) after InO as well as myelosuppression and B-cell aplasia which confer increased infection risk, particularly in combination with cytotoxic chemotherapy. In the relapsed/refractory (R/R) setting, the planned subsequent curative therapy modality must be considered when using InO to mitigate SOS risk if proceeding to HSCT and account for potential B-cell aplasia if proceeding to chimeric antigen receptor CAR-T therapy. Studies exploring mechanisms of resistance or failure of InO are ongoing but modulation or loss CD22 expression, alternative CD22 splicing, and high Bcl-2 expression have been implicated. In this review, we will summarize the currently available data on InO, with an emphasis on pediatric trials, and explore future directions including combinatorial therapy.

Risk factors and outcome of Chimeric Antigen Receptor T-Cell patients admitted to Pediatric Intensive Care Unit: CART-PICU study

Introduction

Chimeric antigen receptor (CAR)T-cell CD19 therapy is an effective treatment for relapsed/refractory B-cell acute lymphoblastic leukemia. It can be associated with life-threatening toxicities which often require PICU admission. Purpose: to describe clinical characteristics, treatment and outcome of these patients.

Methods

Prospective observational cohort study conducted in a tertiary pediatric hospital from 2016-2021. Children who received CAR-T admitted to PICU were included. We collected epidemiological, clinical characteristics, cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), treatment, length of stay and mortality.

Results

CAR T-cells (4-1BB constructs) were infused in 59 patients. Twenty-four (40.7%) required PICU admission, length of stay was 4 days (IQR 3-6). Median age was 8.3 years (range 4-24). Patients admitted to PICU presented higher disease burden before infusion: 24% blasts in bone marrow (IQR 5-72) vs. 0 (0-6.9), p<0.001. No patients with <5% blasts were admitted to PICU. Main reasons for admissions were CRS (n=20, 83.3%) and ICANS (n=3, 12.5%). Fourteen patients (58.3%) required inotropic support, 14(58.3%) respiratory. Sixteen patients (66.6%) received tocilizumab, 10(41.6%) steroids, 6(25.0%) anakinra, and 5(20.8%) siltuximab. Ten patients (41.6%) presented neurotoxicity, six of them severe (ICANS 3-4). Two patients died at PICU (8.3%) because of refractory CRS-hemophagocytic lymphohistyocitosis (carHLH) syndrome. There were no significant differences in relapse rate after CAR-T in patients requiring PICU, it was more frequently CD19 negative (p=0.344).

Discussion

PICU admission after CAR-T therapy was mainly due to CRS. Supportive treatment allowed effective management and high survival. Some patients presenting with carHLH, can suffer a fulminant course.

Chimeric antigen receptor T-cell therapy for adult B-cell acute lymphoblastic leukemia: state-of-the-(C)ART and the road ahead

Autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy has recently been added to the armamentarium in the battle against B-cell acute lymphoblastic leukemia (B-ALL). In this review, we discuss the trials that led to US Food and Drug Administration approval of CAR T-cell therapies in patients with B-ALL. We evaluate the evolving role of allogeneic hematopoietic stem cell transplant in the CAR T-cell era and discuss lessons learned from the first steps with CAR T-cell therapy in ALL. Upcoming innovations in CAR technology, including combined and alternative targets and off-the-shelf allogeneic CAR T-cell strategies are presented. Finally, we envision the role that CAR T cells could take in the management of adult patients with B-ALL in the near future.

Treatment of adult ALL patients with third-generation CD19-directed CAR T cells: results of a pivotal trial

BACKGROUND

Third-generation chimeric antigen receptor (CAR)-engineered T cells (CARTs) might improve clinical outcome of patients with B cell malignancies. This is the first report on a third-generation CART dose-escalating, phase-1/2 investigator-initiated trial treating adult patients with refractory and/or relapsed (r/r) acute lymphoblastic leukemia (ALL).

METHODS

Thirteen patients were treated with escalating doses of CD19-directed CARTs between 1 × 10⁶ and 50 × 10⁶ CARTs/m². Leukapheresis, manufacturing and administration of CARTs were performed in-house.

RESULTS

For all patients, CART manufacturing was feasible. None of the patients developed any grade of Immune effector cell-associated neurotoxicity syndrome (ICANS) or a higher-grade (≥ grade III) catokine release syndrome (CRS). CART expansion and long-term CART persistence were evident in the peripheral blood (PB) of evaluable patients. At end of study on day 90 after CARTs, ten patients were evaluable for response: Eight patients (80%) achieved a complete remission (CR), including five patients (50%) with minimal residual disease (MRD)-negative CR. Response and outcome were associated with the administered CART dose. At 1-year follow-up, median overall survival was not reached and progression-free survival (PFS) was 38%. Median PFS was reached on day 120. Lack of CD39-expression on memory-like T cells was more frequent in CART products of responders when compared to CART products of non-responders. After CART administration, higher CD8 + and γδ-T cell frequencies, a physiological pattern of immune cells and lower monocyte counts in the PB were associated with response.

CONCLUSION

In conclusion, third-generation CARTs were associated with promising clinical efficacy and remarkably low procedure-specific toxicity, thereby opening new therapeutic perspectives for patients with r/r ALL. Trial registration This trial was registered at www.

CLINICALTRIALS

gov as NCT03676504.

HLH-like toxicities predict poor survival after the use of tisagenlecleucel in children and young adults with B-ALL

Chimeric antigen receptor-associated hemophagocytic lymphohistiocytosis (HLH)-like toxicities (LTs) involving hyperferritinemia, multiorgan dysfunction, coagulopathy, and/or hemophagocytosis are described as occurring in a subset of patients with cytokine release syndrome (CRS). Case series report poor outcomes for those with B-cell acute lymphoblastic leukemia (B-ALL) who develop HLH-LTs, although larger outcomes analyses of children and young adults (CAYAs) with B-ALL who develop these toxicities after the administration of commercially available tisagenlecleucel are not described. Using a multi-institutional database of 185 CAYAs with B-ALL, we conducted a retrospective cohort study including groups that developed HLH-LTs, high-grade (HG) CRS without HLH-LTs, or no to low-grade (NLG) CRS without HLH-LTs. Primary objectives included characterizing the incidence, outcomes, and preinfusion factors associated with HLH-LTs. Among 185 CAYAs infused with tisagenlecleucel, 26 (14.1%) met the criteria for HLH-LTs. One-year overall survival and relapse-free survival were 25.7% and 4.7%, respectively, in those with HLH-LTs compared with 80.1% and 57.6%, respectively, in those without. In multivariable analysis for death, meeting criteria for HLH-LTs carried a hazard ratio of 4.61 (95% confidence interval, 2.41-8.83), controlling for disease burden, age, and sex. Patients who developed HLH-LTs had higher pretisagenlecleucel disease burden, ferritin, and C-reactive protein levels and lower platelet and absolute neutrophil counts than patients with HG- or NLG-CRS without HLH-LTs. Overall, CAYAs with B-ALL who developed HLH-LTs after tisagenlecleucel experienced high rates of relapse and nonrelapse mortality, indicating the urgent need for further investigations into prevention and optimal management of patients who develop HLH-LTs after tisagenlecleucel.

The future of CAR T-cell therapy for B-cell acute lymphoblastic leukemia in pediatrics and adolescents

INTRODUCTION

Antigen down-regulation and early chimeric antigen receptor (CAR) T cell loss have emerged as 2 major challenges threatening outcomes following CD19-specific CAR T cell therapy for children and young adults with B-cell acute lymphoblastic leukemia (B-ALL). In addressing the future of CAR T cell therapy for B-ALL, innovative strategies to avert antigen downregulation and enhance CAR persistence warrant prioritized focus.

AREAS COVERED

We describe promising engineering strategies to refine CAR constructs to reverse exhaustion, develop regulatable CARs, optimize manufacturing, enrich for immune memory and disrupt immune inhibition. We additionally focus on alternative targeting to CD19-monospecific targeting and contextualize possibilities for expanded CAR utilization.

EXPERT OPINION

We describe research advances as they are independently reported, however anticipate an integrative strategy incorporating complementary modifications will be required to effectively address CAR loss, overcome antigen downregulation and enhance reliability and durability of CAR T cell responses for B-ALL.

What is Next in Pediatric B-cell Precursor Acute Lymphoblastic Leukemia

Cure rates now exceed 90% in many contemporary trials for children with B-cell acute lymphoblastic leukemia (ALL). However, treatment remains suboptimal and therapy is toxic for all patients. New treatment options potentially offer the chance to reduce both treatment resistance and toxicity. Here, we review recent advances in ALL diagnostics, chemotherapy, and immunotherapy. In addition to describing recently published results, we also attempt to project the impact of these new developments into the future to imagine what B-ALL therapy may look like in the next few years.

Dual targeting of CD19 and CD22 with bicistronic CAR-T cells in patients with relapsed/refractory large B-cell lymphoma

Relapse after CD19-directed chimeric antigen receptor T-cell (CAR-T) therapy for large B-cell lymphoma (LBCL) is commonly ascribed to antigen loss or CAR-T exhaustion. Multiantigen targeting and programmed cell death protein-1 blockade are rational approaches to prevent relapse. Here, we test CD19/22 dual-targeting CAR-T (AUTO3) plus pembrolizumab in relapsed/refractory LBCL (NCT03289455). End points include toxicity (primary) and response rates (secondary). Fifty-two patients received AUTO3 and 48/52 received pembrolizumab. Median age was 59 years (range, 27-83), 46/52 had stage III/ IV disease and median follow-up was 21.6 months. AUTO3 was safe; grade 1-2 and grade 3 cytokine release syndrome affected 18/52 (34.6%) and 1/52 (1.9%) patients, neurotoxicity arose in 4 patients (2/4, grade 3-4), and hemophagocytic lymphohistiocytosis affected 2 patients. Outpatient administration was tested in 20 patients, saving a median of 14 hospital days per patient. Overall response rates were 66% (48.9%, complete response [CR]; 17%, partial response). Median duration of remission (DOR) for CR patients was not reached and for all responding patients was 8.3 months (95% confidence interval [CI]: 3.0-not evaluable). 54.4% (CI: 32.8-71.7) of CR patients and 42.6% of all responding patients were projected to remain progression-free at ≥12 months. AUTO3 ± pembrolizumab for relapsed/refractory LBCL was safe and delivered durable remissions in 54.4% of complete responders, associated with robust CAR-T expansion. Neither dual-targeting CAR-T nor pembrolizumab prevented relapse in a significant proportion of patients, and future developments include next-generation-AUTO3, engineered for superior expansion in vivo, and selection of CAR binders active at low antigen densities.

How I treat refractory CRS and ICANS after CAR T-cell therapy

The clinical use of chimeric antigen receptor (CAR) T-cell therapy is growing rapidly because of the expanding indications for standard-of-care treatment and the development of new investigational products. The establishment of consensus diagnostic criteria for cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), alongside the steady use of both tocilizumab and corticosteroids for treatment, have been essential in facilitating the widespread use. Preemptive interventions to prevent more severe toxicities have improved safety, facilitating CAR T-cell therapy in medically frail populations and in those at high risk of severe CRS/ICANS. Nonetheless, the development of persistent or progressive CRS and ICANS remains problematic because it impairs patient outcomes and is challenging to treat. In this case-based discussion, we highlight a series of cases of CRS and/or ICANS refractory to front-line interventions. We discuss our approach to managing refractory toxicities that persist or progress beyond initial tocilizumab or corticosteroid administration, delineate risk factors for severe toxicities, highlight the emerging use of anakinra, and review mitigation strategies and supportive care measures to improve outcomes in patients who develop these refractory toxicities.

Difference in Efficacy and Safety of Anti-CD19 Chimeric Antigen Receptor T-Cell Therapy Containing 4-1BB and CD28 Co-Stimulatory Domains for B-Cell Acute Lymphoblastic Leukemia

This study quantified the differences in the efficacy and safety of different stimulation domains of anti-CD19 chimeric antigen receptor (CAR) T therapy for B-cell acute lymphoblastic leukemia (B-ALL). Clinical trials related to anti-CD19 CAR T-cell therapy for B-ALL were searched in public databases from database inception to 13 November 2021. The differences in overall survival (OS) and progression-free survival (PFS) of B-ALL patients treated with anti-CAR T-cell therapy containing 4-1BB and CD28 co-stimulatory domains were compared by establishing a parametric survival function. The overall remission rate (ORR), the proportion of people with minimal residual disease (MRD)-negative complete remission (CR), the incidence of cytokine release syndrome (CRS), and the neurotoxicity across different co-stimulatory domains was assessed using a random-effects model. The correlation between the ORR, MRD-negative CR, PFS, and OS was tested. The results showed that the median OS of anti-CAR T-cell treatment containing 4-1BB and CD28 co-stimulatory domains was 15.0 months (95% CI: 11.0-20.0) and 8.5 months (95% CI: 5.0-14.0), and the median PFS was 7.0 months (95% CI: 4.0-11.5) and 3.0 months (95% CI: 1.5-7.0), respectively. Anti-CD19 CAR T-cells in the 4-1BB co-stimulatory domain showed superior benefits in patients who achieved ORR. The incidence of neurotoxicity was significantly higher in the CD28 co-stimulatory domain of anti-CD19 CAR T-cells than in the 4-1BB co-stimulatory domain. In addition, the ORR and MRD-negative CR were strongly correlated with OS and PFS, and PFS and OS were strongly correlated. The 4-1BB co-stimulatory domain suggested a better benefit-risk ratio than the CD28 co-stimulatory domain in B-ALL.

Current status of CAR-T cell therapy for pediatric hematologic malignancies

Acute lymphoblastic leukemia (ALL) is the most common cancer in the pediatric population, and the long-term survival can reach 90%. However, approximately, 20% of pediatric ALL patients experience relapse and require second-line chemotherapy. This is frequently followed by hematopoietic stem cell transplantation, which can cause long-term sequelae. Recent advances in immunotherapy, such as monoclonal antibody therapy and chimeric antigen receptor (CAR)-T cell therapy, have revolutionized the treatment of relapsed and refractory ALL. Anti-CD19 CAR-T cells successfully eliminate B cell malignancies such as ALL. Tisagenlecleucel (Kymriah^®) is the first CAR-T cell immunotherapy approved by the FDA. CAR-T cell therapy can cause specific adverse events (AEs) such as cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome, which are defined and graded according to the consensus grading system and treated with supportive therapies along with tocilizumab and corticosteroids. Other AEs include prolonged bone marrow suppression and hypogammaglobulinemia. Severe AEs are less common in the real-world experience than in clinical trials, probably due to better management of the patient before and during CAR-T cell therapy. The biggest challenge in CAR-T cell therapy against ALL is relapse. A high tumor burden on infusion, early loss of B cell aplasia, and minimal residual disease positivity after CAR-T cell infusion are predictive of relapse. Consolidative stem cell transplantation may improve the long-term outcome. The success of CD19 CAR-T cell therapy against B cell malignancy prompted extensive research into the use of CAR-T cells against other hematologic malignancies such as T cell leukemia or myeloid leukemia.

Long-term outcomes following CAR T cell therapy: what we know so far

Chimeric antigen receptors (CAR) are engineered fusion proteins designed to target T cells to antigens expressed on cancer cells. CAR T cells are now an established treatment for patients with relapsed and/or refractory B cell lymphomas, B cell acute lymphoblastic leukaemia and multiple myeloma. At the time of this writing, over a decade of follow-up data are available from the initial patients who received CD19-targeted CAR T cells for B cell malignancies. Data on the outcomes of patients who received B cell maturation antigen (BCMA)-targeted CAR T cells for multiple myeloma are more limited owing to the more recent development of these constructs. In this Review, we summarize long-term follow-up data on efficacy and toxicities from patients treated with CAR T cells targeting CD19 or BCMA. Overall, the data demonstrate that CD19-targeted CAR T cells can induce prolonged remissions in patients with B cell malignancies, often with minimal long-term toxicities, and are probably curative for a subset of patients. By contrast, remissions induced by BCMA-targeted CAR T cells are typically more short-lived but also generally have only limited long-term toxicities. We discuss factors associated with long-term remissions, including the depth of initial response, malignancy characteristics predictive of response, peak circulating CAR levels and the role of lymphodepleting chemotherapy. We also discuss ongoing investigational strategies designed to improve the length of remission following CAR T cell therapy.