Taking a BiTE out of the CAR T space race

How to Test Human CAR T Cells in Solid Tumors, the Next Frontier of CAR T Cell Therapy

Chimeric antigen receptor (CAR) T cell therapy has proven to be a successful treatment option for leukemias and lymphomas. These encouraging outcomes underscore the potential of adoptive cell therapy for other oncology applications, namely, solid tumors. However, CAR T cells are yet to succeed in treating solid tumors. Unlike liquid tumors, solid tumors create a hostile tumor microenvironment (TME). CAR T cells must traffic to the TME, survive, and retain their function to eradicate the tumor. Nevertheless, there is no universal preclinical model to systematically test candidate CARs and CAR targets for their capacity to infiltrate and eliminate human solid tumors in vivo. Here, we provide a detailed protocol to evaluate human CAR CD4+ helper T cells and CD8+ cytotoxic T cells in immunodeficient (NSG) mice bearing antigen-expressing human solid tumors.

Exploring the High-Grade and Refractory Neurotoxicity of Teclistamab: An Underreported Entity

T-cell re-directing bispecific antibodies targeting B-cell maturation antigens have recently entered real-world use in relapsed/refractory multiple myeloma. While no head-to-head comparison has been done, they have generally been observed to have lower-grade toxicities compared with their chimeric antigen receptor T-cell (CAR-T) counterparts. However, in our real-world, single-institution experience, we have encountered two patients receiving teclistamab who experienced high-grade and refractory immune effector cell-associated neurotoxicity syndrome (ICANS) that did not respond to traditional toxicity mitigation strategies of high-dose corticosteroids or other immunosuppressive therapies. As we increase our use of these novel and vital agents, caution must be warranted.

BiTE-Secreting CAR-γδT as a Dual Targeting Strategy for the Treatment of Solid Tumors

HLA-G is considered as an immune checkpoint protein and a tumor-associated antigen. In the previous work, it is reported that CAR-NK targeting of HLA-G can be used to treat certain solid tumors. However, the frequent co-expression of PD-L1 and HLA-G) and up-regulation of PD-L1 after adoptive immunotherapy may decrease the effectiveness of HLA-G-CAR. Therefore, simultaneous targeting of HLA-G and PD-L1 by multi-specific CAR could represent an appropriate solution. Furthermore, gamma-delta T (γδT) cells exhibit MHC-independent cytotoxicity against tumor cells and possess allogeneic potential. The utilization of nanobodies offers flexibility for CAR engineering and the ability to recognize novel epitopes. In this study, Vδ2 γδT cells are used as effector cells and electroporated with an mRNA-driven, nanobody-based HLA-G-CAR with a secreted PD-L1/CD3ε Bispecific T-cell engager (BiTE) construct (Nb-CAR.BiTE). Both in vivo and in vitro experiments reveal that the Nb-CAR.BiTE-γδT cells could effectively eliminate PD-L1 and/or HLA-G-positive solid tumors. The secreted PD-L1/CD3ε Nb-BiTE can not only redirect Nb-CAR-γδT but also recruit un-transduced bystander T cells against tumor cells expressing PD-L1, thereby enhancing the activity of Nb-CAR-γδT therapy. Furthermore, evidence is provided that Nb-CAR.BiTE redirectes γδT into tumor-implanted tissues and that the secreted Nb-BiTE is restricted to the tumor site without apparent toxicity.

Genetics of Transformed Follicular Lymphoma

Histological transformation (HT) to a more aggressive disease–mostly diffuse large B-cell lymphoma–is considered one of the most dismal events in the clinical course of follicular lymphoma (FL). Current knowledge has not found a single biological event specific for HT, although different studies have highlighted common genetic alterations, such as TP53 and CDKN2A/B loss, and MYC translocations, among others. Together, they increase genomic complexity and mutational burden at HT. A better knowledge of HT pathogenesis would presumably help to find diagnostic biomarkers allowing the identification of patients at high-risk of transformation, as well as the discrimination from patients with FL recurrence, and those who remain in remission. This would also help to identify new drug targets and the design of clinical trials for the treatment of transformation. In the present review we provide a comprehensive overview of the genetic events frequently identified in transformed FL contributing to the switch towards aggressive behaviour, and we will discuss current open questions in the field of HT.

Relapse Mechanism and Treatment Strategy After Chimeric Antigen Receptor T-Cell Therapy in Treating B-Cell Hematological Malignancies

Over the past few decades, immunotherapy has revolutionized the modern medical oncology field. Chimeric antigen receptor (CAR)-T cell therapy has a promising curative effect in the treatment of hematological malignancies. Anti-CD19 CAR-T cells are the most mature CAR-T cells recently studied and in recent years it has achieved a complete remission rate of approximately 90% in the treatment of B-cell acute lymphoblastic leukemia (B-ALL). Although CAR-T cell therapy has greatly alleviated the disease in patients with leukemia or lymphoma, some of them still relapse after treatment. Therefore, in this article, we discuss the factors that may contribute to disease relapse following CAR-T cell therapy and summarize potential strategies to overcome these obstacles, thus providing the possibility of improving standard treatment regimens.