CAR T-cell-associated neurotoxicity in central nervous system hematologic disease: Is it still a concern?

Efficient combination of radiotherapy and CAR-T - A systematic review

Chimeric antigen receptor T (CAR-T) cell therapy, a groundbreaking immunotherapy. However, it faces formidable challenges in treating solid tumors, grappling with issues like poor trafficking, limited penetration, and insufficient persistence within the tumor microenvironment (TME). CAR-T cells are engineered to express receptors that target specific cancer antigens, enhancing their ability to recognize and eliminate cancer cells. This review paper explores the intricate interplay between CAR-T therapy and radiotherapy (RT), investigating their synergistic potential. Radiotherapy, a standard cancer treatment, involves using high doses of radiation to target and damage cancer cells, disrupting their ability to grow and divide. We highlight that RT modulates the TME, augments antigen presentation, and promotes immune cell infiltration, bolstering CAR-T cell-mediated tumor eradication. Molecular insights shed light on RT-induced alterations in tumor stroma, T cell recruitment promotion, and induction of immunogenic cell death. Noteworthy, strategies, such as combining hypofractionated radiotherapy with myeloid-derived suppressor cell blockade, underscore innovative approaches to enhance CAR-T cell therapy in solid tumors. Bridging indications for RT and CAR-T cells in hematological malignancies are discussed, emphasizing scenarios where RT strategically enhances CAR-T cell efficacy. The paper critically evaluates the RT as a bridge compared to traditional chemotherapy, highlighting timing and dosage considerations crucial for optimizing CAR-T therapy outcomes. In summary, the paper provides valuable insights into the intricate molecular mechanisms activated by RT and innovative strategies to improve CAR-T cell therapy, fostering a deeper understanding of their combined potential in cancer treatment.

Expanding the role of CAR T-cell therapy: From B-cell hematological malignancies to autoimmune rheumatic diseases

Chimeric antigen receptor (CAR) T-cell therapy is a form of immunotherapy where the lymphocytes, mostly T-cells, are redirected to specifically recognize and eliminate a target antigen by coupling them with CARs. The binding of CAR and target cell surface antigens leads to vigorous T cell activation and robust anti-tumor immune responses. Areas of implication of CAR T-cell therapies include mainly hematological malignancies (i.e., advanced B-cell cancers); however, recent studies have proven the unprecedented success of the new immunotherapy also in autoimmune rheumatic diseases. We aim to review the recent advances in CAR T-cell therapies in rheumatology but also to address the limitations of their use in the real clinical practice based on the data on their efficacy and safety.

Tumor microenvironment and CAR-T cell immunotherapy in B-cell lymphoma

Chimeric receptor antigen T cell (CAR-T cell) therapy has demonstrated effectiveness and therapeutic potential in the immunotherapy of hematological malignancies, representing a promising breakthrough in cancer treatment. Despite the efficacy of CAR-T cell therapy in B-cell lymphoma, response variability, resistance, and side effects remain persistent challenges. The tumor microenvironment (TME) plays an intricate role in CAR-T cell therapy of B-cell lymphoma. The TME is a complex and dynamic environment that includes various cell types, cytokines, and extracellular matrix components, all of which can influence CAR-T cell function and behavior. This review discusses the design principles of CAR-T cells, TME in B-cell lymphoma, and the mechanisms by which TME influences CAR-T cell function. We discuss emerging strategies aimed at modulating the TME, targeting immunosuppressive cells, overcoming inhibitory signaling, and improving CAR-T cell infiltration and persistence. Therefore, these processes enhance the efficacy of CAR-T cell therapy and improve patient outcomes in B-cell lymphoma. Further research will be needed to investigate the molecular and cellular events that occur post-infusion, including changes in TME composition, immune cell interactions, cytokine signaling, and potential resistance mechanisms. Understanding these processes will contribute to the development of more effective CAR-T cell therapies and strategies to mitigate treatment-related toxicities.

Bispecific BCMA/CD24 CAR-T cells control multiple myeloma growth

Anti-multiple myeloma B cell maturation antigen (BCMA)-specific chimeric antigen receptor (CAR) T-cell therapies represent a promising treatment strategy with high response rates in myeloma. However, durable cures following anti-BCMA CAR-T cell treatment of myeloma are rare. One potential reason is that a small subset of minimal residual myeloma cells seeds relapse. Residual myeloma cells following BCMA-CAR-T-mediated treatment show less-differentiated features and express stem-like genes, including CD24. CD24-positive myeloma cells represent a large fraction of residual myeloma cells after BCMA-CAR-T therapy. In this work, we develop CD24-CAR-T cells and test their ability to eliminate myeloma cells. We find that CD24-CAR-T cells block the CD24-Siglec-10 pathway, thereby enhancing macrophage phagocytic clearance of myeloma cells. Additionally, CD24-CAR-T cells polarize macrophages to a M1-like phenotype. A dual-targeted BCMA-CD24-CAR-T exhibits improved efficacy compared to monospecific BCMA-CAR-T-cell therapy. This work presents an immunotherapeutic approach that targets myeloma cells and promotes tumor cell clearance by macrophages.

Epileptic seizures in patients with primary central nervous system lymphoma: A systematic review

BACKGROUND

Primary central nervous system lymphoma (PCNSL) accounts for less than 5% of primary brain tumors. Epileptic seizures are a common manifestation of brain tumors; however, literature on the prevalence, characteristics, and oncological implications of seizures in patients with PCNSL is limited, and the management of antiepileptic drugs (AEDs) is unclear. This review aimed to summarize the existing knowledge on seizures in PCNSL, their potential association with surgery, oncological treatment, survival rates, and management of AEDs.

METHODS

A systematic review was performed according to the PRISMA recommendations and included articles published between 1953 and 2023 describing seizures in patients with PCNSL.

RESULTS

The search identified 282 studies, of which 21 were included. Up to 33% of patients with PCNSL developed seizures, mostly at the initial presentation. Little information was found on changes in seizure incidence through the course of the disease, and no details were found on seizure frequency, the percentage of treatment-resistant patients, or the evolution of seizures at remission. Younger age, cortical location, and immunodeficiency have been identified as potential risk factors for seizures, but evidence is very limited. The growing use of vigorous treatments including intensive chemotherapy with autologous stem cell transplantation and immunotherapy with CAR-T cells is associated with a higher incidence of seizures. The association between seizure development and patient mortality in PCNSL remains unknown. There are no data on AED prophylaxis or the use of specific AEDs in PCNSL.

CONCLUSIONS

Further studies are needed to investigate seizures in larger cohorts of PCNSL, to clarify their prevalence, better characterize them, identify risk factors, analyze survival rates, and make recommendations on AED management. We recommend following general practice guidelines for seizures symptomatic of brain tumors and not to prescribe AED prophylaxis in PCNSL.

The shifting roles and toxicities of cellular therapies in B-cell malignancies

Cellular therapies provide a curative-intent option for patients with relapsedand refractory lymphomas. Current options including high dose chemotherapyfollowed by autologous or allogeneic hematopoietic stem cell transplantation or CD19 chimericantigen receptor T-cell (CART) therapy. The indication varies according to lymphoma sub-type and line oftherapy. The sequencing of these therapies and their use in second-line orlater settings to manage these diseases is undergoing significant changes, withCD19 CAR T becoming a preferred option for relapsed aggressive B-cell lymphoma.The mechanism of both therapies causes significant yet distinctlymphodepletion, infectious, and inflammatory toxicities. The resulting patternand timing of immune reconstitution helps guide risk-mitigating strategies,revaccination, and infectious prophylaxis. In this review, we discuss theindication, efficacy, toxicity and immune reconstitution of autologoushematopoietic stem cell transplantation and CAR T therapy for use in thetreatment of lymphoma.

Chimeric Antigen Receptor T Cells: Immunotherapy for the Treatment of Leukemia, Lymphoma, and Myeloma

In immunotherapy with T cells genetically modified to express chimeric antigen receptors (CAR), autologous lymphocytes are extracted from the patient, genetically modified to obtain CAR-T cells, and reintroduced into the patient to attack cancer cells. The success of this therapy has been achieved in the area of CD19-positive leukemias and lymphomas, being approved for the treatment of non-Hodgkin's lymphomas, acute lymphoblastic leukemia, and multiple myeloma. CARs are proteins that combine antibody specificity with T-cell cytotoxicity. The most common toxicities associated with therapy were not predicted by preclinical testing and include cytokine release syndrome, neurotoxicity, and cytopenias. These toxicities are usually reversible. One of the main challenges facing the field is the high economic cost that therapy entails, so the search for ways to reduce this cost must be a priority. In addition, other challenges to overcome include the situation that not all patients are supplied with the product and the existence of long waiting times for the start of therapy. The aim of this review is to present the development of the structure of CAR-T cells, the therapies approved to date, the toxicity associated with them, and the advantages and limitations that they present as immunotherapy.

Bi- and trispecific immune cell engagers for immunotherapy of hematological malignancies

Immune cell engagers are engineered antibodies with at least one arm binding a tumor-associated antigen and at least another one directed against an activating receptor in immune effector cells: CD3 for recruitment of T cells and CD16a for NK cells. The first T cell engager (the anti-CD19 blinatumomab) was approved by the FDA in 2014, but no other one hit the market until 2022. Now the field is gaining momentum, with three approvals in 2022 and 2023 (as of May): the anti-CD20 × anti-CD3 mosunetuzumab and epcoritamab and the anti-B cell maturation antigen (BCMA) × anti-CD3 teclistamab, and another three molecules in regulatory review. T cell engagers will likely revolutionize the treatment of hematological malignancies in the short term, as they are considerably more potent than conventional monoclonal antibodies recognizing the same tumor antigens. The field is thriving, with a plethora of different formats and targets, and around 100 bispecific T cell engagers more are already in clinical trials. Bispecific NK cell engagers are also in early-stage clinical studies and may offer similar efficacy with milder side effects. Trispecific antibodies (engaging either T cell or NK cell receptors) raise the game even further with a third binding moiety, which allows either the targeting of an additional tumor-associated antigen to increase specificity and avoid immune escape or the targeting of additional costimulatory receptors on the immune cell to improve its effector functions. Altogether, these engineered molecules may change the paradigm of treatment for relapsed or refractory hematological malignancies.