INSPIRED Symposium Part 2: Prevention and Management of Relapse Following Chimeric Antigen Receptor T Cell Therapy for B Cell Acute Lymphoblastic Leukemia

CAR T-cells for acute leukemias in children: current status, challenges, and future directions

CAR T-cells therapy is seen as one of the most promising immunotherapies for leukemias, since targeting CD19 has revolutionized the treatment of relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL) in children, adolescents, and young adults. Early phase clinical trials have shown a very high initial response rate confirmed by follow up and real-world studies. However, almost half of patients relapse with the available commercial product currently suggesting the need of a consolidative treatment after CAR T-cell infusion in well-defined cases, according to several pre- and post-CAR clinical and biological factors. This finding highlights that numerous challenges exist before the extension of CAR T-cell indications (first relapse and high-risk first line) in the field of B-ALL: to enhance persistence of CAR T-cells to avoid CD19-positive relapse and to avoid CD19-negative relapse by reducing tumor burden pre-CAR-T infusion and/or by multitargeting. Promising approaches with exciting early clinical data are emerging in the field of T-cell ALL. The use of CAR T-cells for acute myeloid leukemias remains challenging due to the lack of leukemia-specific antigens and to the immunosuppressive microenvironment.

The present and future of CAR T-cell therapy for adult B-cell ALL

ABSTRACT

Chimeric antigen receptor T-cell therapy (CAR-T) targeting CD19 has transformed the management of relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL), with the US Food and Drug Administration approval of tisagenlecleucel for pediatric/young adult patients and brexucabtagene autoleucel for adults. Efficacy is contingent upon several factors including disease burden. Emerging data suggest that bridging therapy, lymphodepletion, and, for some patients, consolidation therapy have an important role in the success of treatment. Furthermore, strategies to define and manage immunotoxic side effects including hematotoxicity is critical to safe delivery. Advancements in CAR-T design beyond CD19 represent an ongoing therapeutic evolution. Overall, CAR-T signifies a paradigm shift in B-ALL management, with the potential for improved remission and survival in a historically challenging patient population.

How I treat postimmunotherapy relapsed B-ALL

ABSTRACT

Despite significant advancements in single-antigen targeted therapies for B-cell acute lymphoblastic leukemia (B-ALL), nonresponse and relapse persist as major challenges. Antigen escape after blinatumomab or CD19-directed chimeric antigen receptor (CAR) T cells (CD19-CAR), as CD19-negative B-ALL or lineage switch (LS) to acute myeloid leukemia, present diagnostic and treatment complexities. Given the poor outcomes for patients experiencing a postinfusion relapse, particularly those with loss of the target antigen, a strategic approach to diagnosis and treatment is imperative. In this discussion, we outline a systematic approach to managing postimmunotherapy events, categorized by CD19-positive relapse, CD19-negative relapse, and LS. We explore treatment modalities including CD19-CAR reinfusions, humanized CAR constructs, combinatorial strategies, and alternative antigen-targeted therapies, such as blinatumomab and inotuzumab. Challenges in diagnosis, particularly with antigen-escape, are addressed, highlighting the role of next-generation sequencing and multiparameter flow cytometry for myeloid marker monitoring.

Rare Hematologic Malignancies and Pre-Leukemic Entities in Children and Adolescents Young Adults

There are a variety of rare hematologic malignancies and germline predispositions syndromes that occur in children and adolescent young adults (AYAs). These entities are important to recognize, as an accurate diagnosis is essential for risk assessment, prognostication, and treatment. This descriptive review summarizes rare hematologic malignancies, myelodysplastic neoplasms, and germline predispositions syndromes that occur in children and AYAs. We discuss the unique biology, characteristic genomic aberrations, rare presentations, diagnostic challenges, novel treatments, and outcomes associated with these rare entities.

Harnessing the Transcriptional Signatures of CAR-T-Cells and Leukemia/Lymphoma Using Single-Cell Sequencing Technologies

Chimeric antigen receptor (CAR)-T-cell therapy has greatly improved outcomes for patients with relapsed or refractory hematological malignancies. However, challenges such as treatment resistance, relapse, and severe toxicity still hinder its widespread clinical application. Traditional transcriptome analysis has provided limited insights into the complex transcriptional landscape of both leukemia cells and engineered CAR-T-cells, as well as their interactions within the tumor microenvironment. However, with the advent of single-cell sequencing techniques, a paradigm shift has occurred, providing robust tools to unravel the complexities of these factors. These techniques enable an unbiased analysis of cellular heterogeneity and molecular patterns. These insights are invaluable for precise receptor design, guiding gene-based T-cell modification, and optimizing manufacturing conditions. Consequently, this review utilizes modern single-cell sequencing techniques to clarify the transcriptional intricacies of leukemia cells and CAR-Ts. The aim of this manuscript is to discuss the potential mechanisms that contribute to the clinical failures of CAR-T immunotherapy. We examine the biological characteristics of CAR-Ts, the mechanisms that govern clinical responses, and the intricacies of adverse events. By exploring these aspects, we hope to gain a deeper understanding of CAR-T therapy, which will ultimately lead to improved clinical outcomes and broader therapeutic applications.