CD19 chimeric antigen receptor-T cells in B-cell leukemia and lymphoma: current status and perspectives

CD19 CAR T cells for B cell malignancies: a systematic review and meta-analysis focused on clinical impacts of CAR structural domains, manufacturing conditions, cellular product, doses, patient's age, and tumor types

CD19-targeted chimeric antigen receptors (CAR) T cells are one of the most remarkable cellular therapies for managing B cell malignancies. However, long-term disease-free survival is still a challenge to overcome. Here, we evaluated the influence of different hinge, transmembrane (TM), and costimulatory CAR domains, as well as manufacturing conditions, cellular product type, doses, patient's age, and tumor types on the clinical outcomes of patients with B cell cancers treated with CD19 CAR T cells. The primary outcome was defined as the best complete response (BCR), and the secondary outcomes were the best objective response (BOR) and 12-month overall survival (OS). The covariates considered were the type of hinge, TM, and costimulatory domains in the CAR, CAR T cell manufacturing conditions, cell population transduced with the CAR, the number of CAR T cell infusions, amount of CAR T cells injected/Kg, CD19 CAR type (name), tumor type, and age. Fifty-six studies (3493 patients) were included in the systematic review and 46 (3421 patients) in the meta-analysis. The overall BCR rate was 56%, with 60% OS and 75% BOR. Younger patients displayed remarkably higher BCR prevalence without differences in OS. The presence of CD28 in the CAR's hinge, TM, and costimulatory domains improved all outcomes evaluated. Doses from one to 4.9 million cells/kg resulted in better clinical outcomes. Our data also suggest that regardless of whether patients have had high objective responses, they might have survival benefits from CD19 CAR T therapy. This meta-analysis is a critical hypothesis-generating instrument, capturing effects in the CD19 CAR T cells literature lacking randomized clinical trials and large observational studies.

Acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) is a haematological malignancy characterized by the uncontrolled proliferation of immature lymphoid cells. Over past decades, significant progress has been made in understanding the biology of ALL, resulting in remarkable improvements in its diagnosis, treatment and monitoring. Since the advent of chemotherapy, ALL has been the platform to test for innovative approaches applicable to cancer in general. For example, the advent of omics medicine has led to a deeper understanding of the molecular and genetic features that underpin ALL. Innovations in genomic profiling techniques have identified specific genetic alterations and mutations that drive ALL, inspiring new therapies. Targeted agents, such as tyrosine kinase inhibitors and immunotherapies, have shown promising results in subgroups of patients while minimizing adverse effects. Furthermore, the development of chimeric antigen receptor T cell therapy represents a breakthrough in ALL treatment, resulting in remarkable responses and potential long-term remissions. Advances are not limited to treatment modalities alone. Measurable residual disease monitoring and ex vivo drug response profiling screening have provided earlier detection of disease relapse and identification of exceptional responders, enabling clinicians to adjust treatment strategies for individual patients. Decades of supportive and prophylactic care have improved the management of treatment-related complications, enhancing the quality of life for patients with ALL.

Valrubicin-loaded immunoliposomes for specific vesicle-mediated cell death in the treatment of hematological cancers

We created valrubicin-loaded immunoliposomes (Val-ILs) using the antitumor prodrug valrubicin, a hydrophobic analog of daunorubicin. Being lipophilic, valrubicin readily incorporated Val-lLs that were loaded with specific antibodies. Val-ILs injected intravenously rapidly reached the bone marrow and spleen, indicating their potential to effectively target cancer cells in these areas. Following the transplantation of human pediatric B-cell acute lymphoblastic leukemia (B-ALL), T-cell acute lymphoblastic leukemia (T-ALL), or acute myeloid leukemia (AML) in immunodeficient NSG mice, we generated patient-derived xenograft (PDX) models, which were treated with Val-ILs loaded with antibodies to target CD19, CD7 or CD33. Only a small amount of valrubicin incorporated into Val-ILs was needed to induce leukemia cell death in vivo, suggesting that this approach could be used to efficiently treat acute leukemia cells. We also demonstrated that Val-ILs could reduce the risk of contamination of CD34+ hematopoietic stem cells by acute leukemia cells during autologous peripheral blood stem cell transplantation, which is a significant advantage for clinical applications. Using EL4 lymphoma cells on immunocompetent C57BL/6 mice, we also highlighted the potential of Val-ILs to target immunosuppressive cell populations in the spleen, which could be valuable in impairing cancer cell expansion, particularly in lymphoma cases. The most efficient Val-ILs were found to be those loaded with CD11b or CD223 antibodies, which, respectively, target the myeloid-derived suppressor cells (MDSC) or the lymphocyte-activation gene 3 (LAG-3 or CD223) on T4 lymphocytes. This study provides a promising preclinical demonstration of the effectiveness and ease of preparation of Val-ILs as a novel nanoparticle technology. In the context of hematological cancers, Val-ILs have the potential to be used as a precise and effective therapy based on targeted vesicle-mediated cell death.

[Safety and efficacy of donor-derived chimeric antigen receptor T-cell therapy in patients with relapsed B-cell acute lymphoblastic leukemia after allogeneic hematopoietic stem cell transplantation]

Objective: To investigated the safety and efficacy of donor-derived CD19+ or sequential CD19+ CD22+ chimeric antigen receptor T-cell (CAR-T) therapy in patients with B-cell acute lymphoblastic leukemia (B-ALL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: The data of 22 patients with B-ALL who relapsed after allo-HSCT and who underwent donor-derived CAR-T therapy at the Zhujiang Hospital of Southern Medical University and the 920th Hospital of Joint Logistics Support Force of the People's Liberation Army of China from September 2015 to December 2022 were retrospectively analyzed. The primary endpoint was overall survival (OS), and the secondary endpoints were event-free survival (EFS), complete remission (CR) rate, and Grade 3-4 adverse events. Results: A total of 81.82% (n=18) of the 22 patients achieved minimal residual disease-negative CR after CAR-T infusion. The median follow-up time was 1037 (95% CI 546-1509) days, and the median OS and EFS were 287 (95% CI 132-441) days and 212 (95% CI 120-303) days, respectively. The 6-month OS and EFS rates were 67.90% (95% CI 48.30%-84.50%) and 58.70% (95% CI 37.92%-79.48%), respectively, and the 1-year OS and EFS rates were 41.10% (95% CI 19.15%-63.05%) and 34.30% (95% CI 13.92%-54.68%), respectively. Grade 1-2 cytokine release syndrome occurred in 36.36% (n=8) of the patients, and grade 3-4 occurred in 13.64% of the patients (n=3). Grade 2 and 4 graft-versus-host disease occurred in two patients. Conclusion: Donor-derived CAR-T therapy is safe and effective in patients with relapsed B-ALL after allo-HSCT.

Targeting colorectal cancer cells using AND-gated adaptor RevCAR T-cells

Despite the success of chimeric antigen receptor (CAR) T-cells especially for treating hematological malignancies, critical drawbacks, such as "on-target, off-tumor" toxicities, need to be addressed to improve safety in translating to clinical application. This is especially true, when targeting tumor-associated antigens (TAAs) that are not exclusively expressed by solid tumors but also on hea9lthy tissues. To improve the safety profile, we developed switchable adaptor CAR systems including the RevCAR system. RevCAR T-cells are activated by cross-linking of bifunctional adaptor molecules termed target modules (RevTM). In a further development, we established a Dual-RevCAR system for an AND-gated combinatorial targeting by splitting the stimulatory and co-stimulatory signals of the RevCAR T-cells on two individual CARs. Examples of common markers for colorectal cancer (CRC) are the carcinoembryonic antigen (CEA) and the epithelial cell adhesion molecule (EpCAM), while these antigens are also expressed by healthy cells. Here we describe four novel structurally different RevTMs for targeting of CEA and EpCAM. All anti-CEA and anti-EpCAM RevTMs were validated and the simultaneous targeting of CEA+ and EpCAM+ cancer cells redirected specific in vitro and in vivo killing by Dual-RevCAR T-cells. In summary, we describe the development of CEA and EpCAM specific adaptor RevTMs for monospecific and AND-gated targeting of CRC cells via the RevCAR platform as an improved approach to increase tumor specificity and safety of CAR T-cell therapies.

Patient-reported outcome (PRO) instruments used in patients undergoing adoptive cell therapy (ACT) for the treatment of cancer: a systematic review

INTRODUCTION

Adoptive cell therapy (ACT) is a rapidly evolving field. Patient-reported outcomes (PROs) allow patients to report the impact of treatment on their quality of life during and after treatment. The systematic review aims to characterise the breadth of PROs utilised in ACT cancer care and provide guidance for the use of PROs in this patient population in the future.

METHODS

A systematic search was conducted (MEDLINE, PsycINFO, Embase and CINAHL) in August 2021 by two reviewers. Search terms covered the following: "adoptive cell therapy", "patient-reported outcomes" and "cancer". Studies were included if they used a PRO measure to report the impact of ACT. The methodological quality of PROs was assessed. Forward and backward reference searching was conducted of any relevant papers. A quality grading scale was applied based on Cochrane and Revenson criteria for classification of high-quality studies. Key data from the studies and the included PROs was extracted by two researchers and tabulated.

RESULTS

One-hundred nine papers were identified; 11 papers were included. The majority of studies were single-arm trials or observational studies. Twenty-two different PROs were identified; none was ACT specific. The PROMIS-29 and EQ-5D were most commonly used. Few studies collected PRO data in the first 1-2 weeks. Four studies followed patients up for over a year, and a further four studies followed patients for approximately 3 months.

DISCUSSION

None of the PROs identified have been designed specifically for ACT. Appropriateness of existing instruments should be considered. It should be considered whether it is appropriate to collect data more frequently in the acute stage and then less frequently during follow-up. It should be considered if one tool is suitable at all time points or if the tool should be adapted depending on time since treatment. More research is needed to identify the exact timings of PRO assessments, and qualitative work with patients is needed to determine the most important issues for them throughout the treatment and follow-up.

Advances in Immunotherapy for the Treatment of Cutaneous T-Cell Lymphoma

Cutaneous T-Cell Lymphoma (CTCL) is a heterogenous disease that consists of distinct clinicopathologic entities and presentations requiring a unique and expert approach to management. The most common subtype is mycosis fungoides, in which local disease has an excellent prognosis and is often managed with topical therapy alone. More extensive cutaneous involvement as well as involvement of lymph nodes and the peripheral blood (Sezary syndrome) require systemic therapies. Recent years have brought an expansion of therapeutic options, specifically with immune-based approaches that were developed using the knowledge gained regarding the biology and molecular pathology of CTCL. Previous systemic therapies such as retinoids, histone deacetylase inhibitors, and chemotherapeutic agents come with significant toxicity and only short-term response. Newer agents such as mogamulizumab and brentuximab vedotin use a targeted immune-based approach leading to longer periods of response with less systemic toxicity. While still in its infancy, the use of immune checkpoint inhibitors such as nivolumab and pembrolizumab appears promising, and while their current clinical application is limited, early data suggest possible future areas for research of immune manipulation to treat CTCL. Herein, we review these novel immune-based treatment strategies, their superiority over prior systemic options, and the ongoing need for further research and clinical trial enrollment.

Do CAR-T and Allogeneic Stem Cell Transplant Both Have a Place in Lymphoid Neoplasms?

Allogeneic stem cell transplantation (allo-SCT) represented the first immunotherapy to treat hematologic malignancies: it has been considered as a cure for the disease and never as an approach to extend the life of patients. The success of allo-SCT derives both from the ability to treat patients with intensive chemoradiotherapy and from the potent graft-versus-leukemia effects mediated by donor immunity. Although considerable progress has been made in the last years, significant barriers still remain in the form of disease relapse, graft-versus-host disease, infectious complications, and regimen-related toxicities. Moreover, the treatment of hematologic malignancies, particularly acute lymphoblastic leukemia and certain forms of lymphomas, has been revolutionized by the commercial introduction of genetically modified autologous T-lymphocyte therapy (CAR-T). Our review discusses current standards and the shifting paradigms in the indications for allo-SCT and the role of CAR-T cell therapy for lymphoid neoplasms.

DAP10 integration in CAR-T cells enhances the killing of heterogeneous tumors by harnessing endogenous NKG2D

Although chimeric antigen receptor T (CAR-T) cells have achieved remarkable successes in hematological malignancies, the efficacies of CAR-T cells against solid tumors remains unsatisfactory. Heterogeneous antigen expression is one of the obstacles on its effective elimination of solid cancer cells. DNAX-activating protein 10 (DAP10) interacts with natural killer group 2D (NKG2D), acting as an adaptor that targets various malignant cells for surveillance. Here, we designed a DAP10 chimeric receptor that utilized native NKG2D on T cells to target NKG2D ligand-expressing cancer cells. We then tandemly incorporated it with anti-glypican 3 (GPC3) single-chain variable fragment (scFv) to construct a dual-antigen-targeting system. T cells expressing DAP10 chimeric receptor (DAP10-T cells) displayed with an enhancement on both cytotoxicity and cytokine secretion against solid cancer cell lines, and its tandem connection with anti-GPC3 scFv (CAR GPC3-DAP10-T cells) exhibited a dual-antigen-targeting capacity on eliminating heterogeneous cancer cells in vitro and suppressing the growth of heterogeneous cancer in vivo. Thus, this novel dual-targeting system enabled a high efficacy on killing cancer cells and extended the recognition profile of CAR-T cells toward tumors, which providing a potential strategy on treatment of solid cancer clinically.

Role of CD19 Chimeric Antigen Receptor T Cells in Second-Line Large B Cell Lymphoma: Lessons from Phase 3 Trials. An Expert Panel Opinion from the American Society for Transplantation and Cellular Therapy

Since 2017, 3 CD19-directed chimeric antigen receptor (CAR) T cell therapies-axicabtagene ciloleucel, tisagenlecleucel, and lisocabtagene maraleucel-have been approved for relapsed/refractory aggressive diffuse large B cell lymphoma after 2 lines of therapy. Recently, 3 prospective phase 3 randomized clinical trials were conducted to define the optimal second-line treatment by comparing each of the CAR T cell products to the current standard of care: ZUMA-7 for axicabtagene ciloleucel, BELINDA for tisagenlecleucel, and TRANSFORM for lisocabtagene maraleucel. These 3 studies, although largely addressing the same question, had different outcomes, with ZUMA-7 and TRANSFORM demonstrating significant improvement with CD19 CAR T cells in second-line therapy compared with standard of care but BELINDA not showing any benefit. The US Food and Drug Administration has now approved axicabtagene ciloleucel and lisocabtagene maraleucel for LBCL that is refractory to first-line chemoimmunotherapy or relapse occurring within 12 months of first-line chemoimmunotherapy. Following the reporting of these practice changing studies, here a group of experts convened by the American Society for Transplantation and Cellular Therapy provides a comprehensive review of the 3 studies, emphasizing potential differences, and shares perspectives on what these results mean to clinical practice in this new era of treatment of B cell lymphomas.

A novel anti-B7-H3 chimeric antigen receptor from a single-chain antibody library for immunotherapy of solid cancers

B7-H3 (CD276) has emerged as a target for cancer immunotherapy by virtue of consistent expression in many malignancies, relative absence from healthy tissues, and an emerging role as a driver of tumor immune inhibition. Recent studies have reported B7-H3 to be a suitable target for chimeric antigen receptor-modified T cell (CAR-T) therapy using CARs constructed from established anti-B7-H3 antibodies converted into single-chain Fv format (scFv). We constructed and screened binders in an scFv library to generate a new anti-B7-H3 CAR-T with favorable properties. This allowed access to numerous specificities ready formatted for CAR evaluation. Selected anti-human B7-H3 scFvs were readily cloned into CAR-T and evaluated for anti-tumor reactivity in cytotoxicity, cytokine, and proliferation assays. Two binders with divergent complementarity determining regions were found to show optimal antigen-specific cytotoxicity and cytokine secretion. One binder in second-generation CD28-CD3ζ CAR format induced sustained in vitro proliferation on repeat antigen challenge. The lead candidate CAR-T also demonstrated in vivo activity in a resistant neuroblastoma model. An empirical approach to B7-H3 CAR-T discovery through screening of novel scFv sequences in CAR-T format has led to the identification of a new construct with sustained proliferative capacity warranting further evaluation.

Digital PCR for Minimal Residual Disease Quantitation Using Immunoglobulin/T-Cell Receptor Gene Rearrangements in Acute Lymphoblastic Leukemia: A Proposed Analytic Algorithm

In minimal residual disease (MRD), where there are exceedingly low target copy numbers, digital PCR (dPCR) can improve MRD quantitation. However, standards for dPCR MRD interpretation in acute lymphoblastic leukemia are lacking. Here, for immunoglobulin/T-cell receptor-based MRD, we propose an objective, statistics-based analytic algorithm. In 161 postinduction samples from 79 children with acute lymphoblastic leukemia, MRD was performed by dPCR and real-time quantitative PCR (qPCR) using the same markers and primer-probe sets. The dPCR raw data were analyzed by using an automated algorithm. dPCR and qPCR results were highly concordant (P < 0.0001): 98% (50 of 51) of qPCR positive were positive by dPCR, whereas 95% (61 of 64) of qPCR negative results were also negative by dPCR. For MRD quantitation, both qPCR and dPCR were tightly correlated (R² = 0.94). Using more DNA (1 μg × 7 versus 630 ng × 3), dPCR improved sensitivity of MRD quantitation by one log₁₀ (median MRD positive cutoff 1.6 × 10^-5). With dPCR, 83% (29 of 35) of positive-not-quantifiable results by qPCR could be assigned positive/negative MRD status. Seven replicates of tested samples and negative controls were optimal. Compared with qPCR, dPCR could improve MRD sensitivity by one log₁₀. We proposed an automatable, statistics-based algorithm that minimized interoperator variance for dPCR MRD.

[Preparation of CD52-targeted chimeric antigen receptor-modified T cells and their anti-leukemia effects]

Objective: To construct chimeric antigen receptor (CAR) T cells targeting CD52 (CD52 CAR-T) and validate the effect of CD52 CAR-T cells on CD52-positive leukemia. Methods: A second-generation CD52-targeting CAR bearing 4-1BB costimulatory domain was ligated into a lentiviral vector through molecular cloning. Lentivirus was prepared and packaged by 293 T cells with a four-plasmid system. Fluorescein was used to label cell surface antigens to evaluate the phenotype of CD52 CAR-T cells after infection. Flow cytometry and ELISA were used to evaluate the specific cytotoxicity of CD52 CAR-T cells to CD52-positive cell lines in vitro. Results: ①A pCDH-CD52scFv-CD8α-4-1BB-CD3ζ-GFP expressing plasmid was successfully constructed and used to transduce T cells expressing a novel CD52-targeting CAR. ②On day 6, CD52-positive T cells were almost killed by CD52-targeted CAR-T post lentivirus transduction [CD52 CAR-T (4.48 ± 4.99) %, vs Vector-T (56.58±19.8) %, P=0.011]. ③T cells transduced with the CAR targeting CD52 showed low levels of apoptosis and could be expanded long-term ex vivo. ④The CD52 CAR could promote T cell differentiation into central and effector memory T cells, whereas the proportion of T cells with a CD45RA(+) effector memory phenotype were reduced. ⑤CD52 CAR-T cells could specifically kill CD52-positive HuT78-19t cells but had no killing effect on CD52-negative MOLT4-19t cells. For CD52 CAR-T cells, the percentage of residual of HuT78-19t cells was (2.66±1.60) % at an the E:T ratio of 1∶1 for 24 h, while (56.66±5.74) % of MOLT4-19t cells survived (P<0.001) . ⑥The results of a degranulation experiment confirmed that HuT78-19t cells significantly activated CD52 CAR-T cells but not MOLT4-19t cells[ (57.34±11.25) % vs (13.06± 4.23) %, P<0.001]. ⑦CD52 CAR-T cells released more cytokines when co-cultured with HuT78-19t cells than that of vector-T cells [IFN-γ: (3706±226) pg/ml, P<0.001; TNF-α: (1732±560) pg/ml, P<0.01]. Conclusions: We successfully prepared CD52 CAR-T cells with anti-leukemia effects, which might provide the foundation for further immunotherapy.

Chimeric antigen receptor T cells targeting CD147 for non-small cell lung cancer therapy

Non-small cell lung cancer (NSCLC) is a highly malignant tumor, with a significant mortality and morbidity. With the development of tumor immunotherapy, chimeric antigen receptor T cells (CART) gets increasingly attention and achieves prominent contributions in the treatment of hematologic malignancies. However, CART therapy for NSCLC proceeds slowly and further researches need to be investigated. In our study, we performed bioinformatics analysis to evaluate the significant role of CD147 in NSCLC. The expression level of CD147 was detected in human NSCLC cell lines and NSCLC tissues. Meanwhile, CD147-CART was constructed and identified. Cell cytotoxicity and cytokine secretion were performed to evaluate the efficacy of CD147-CART. We also constructed cell-derived xenograft (CDX) model and patient-derived xenograft (PDX) model, which was used to further investigate the safety and efficacy of CD147-CART in vivo. Our observations show that CD147 is a specific tumor antigen of NSCLC and plays an essential role in NSCLC progression, which can be used as a target for CART therapy in NSCLC. CD147-CART cells exhibit robust cytotoxicity and cytokine production in vitro, suggesting a strong anti-tumor activity against NSCLC tumor cells. Importantly, CD147-CART cells have strong anti-tumor activity against NSCLC cells in vivo in both CDX and PDX models and no adverse side effects. Our findings show that CD147-CART immunotherapy for NSCLC is safe and effective, which is an ideal and promising medical patch for treating NSCLC.

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

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

Successful Treatment of Refractory and Relapsed CNS Acute Lymphoblastic Leukemia With CD-19 CAR-T Immunotherapy: A Case Report

In recent decades, survival was significantly improved in B cell acute lymphoblastic leukemia (B-ALL) patients. But refractory and relapsed B-ALL still has aggressive clinical behavior and poor prognosis. Especially, the patients with central nervous system infiltration is very difficult to achieve complete remissions with routine treatment. Chimeric antigen receptor-modified T-cell therapy targeting CD-19 has shown to be a beneficial treatment approach in refractory and relapsed B cell acute lymphoblastic leukemia (r/r ALL). However, there are very few studies reporting to treatment of refractory and relapsed B cell ALL with central nervous system infiltration. Here, we reported one single case of a patient diagnosed with relapsed B cell ALL with CNS infiltration who was successfully treated by second generation CAR containing a co-stimulator CD28 or 4-1BB therapy. Long-term proliferation of CAR-T cells in peripheral blood and bone marrow was observed more than 18 months. After CAR-T treatment, the patient got toxicity of grade 1 cytokine release syndrome and achieved significantly 36 months event free survival of follow-up. It is suggested that CD-19 CAR containing CD28 or 4-1BB costimulatory may be an effective therapy in refractory and relapsed B cell ALL with central nervous system infiltration. Its toxicity is mild, and its safety is high.

Clinical Trial Registration:ClinicalTrials.gov Identifier: NCT02349698.

Advances in Immunotherapy for Diffuse Large B Cell Lymphoma

Diffuse large B cell lymphoma (DLBCL) is a heterogeneous disease that is normally treated with combination chemotherapy combined with the anti-CD20 monoclonal antibody rituximab. Although about two-thirds of patients are cured with initial chemo-immunotherapy, a sizable minority of patients will have relapsed or refractory (r/r) DLBCL. Standard therapy for r/r DLBCL is salvage chemotherapy followed by autologous stem cell transplantation (ASCT); however, a minority of patients have long-term remission with this approach. In recent years, there has been a proliferation of immunotherapies for the treatment of DLBCL that have expanded our treatment options for these patients, providing the opportunity for durable remissions that were not previously possible. In this review, we discuss these novel immunotherapies, including monoclonal antibodies, antibody-drug conjugates, bispecific antibodies and chimeric antigen receptor (CAR) T cells. The plethora of novel agents leaves patients with more therapeutic options, but leaves the practitioner faced with challenging decisions regarding the timing and indications for use of these immunotherapies. Although studies are ongoing, no agents have been verified as alternatives to standard salvage therapy followed by ASCT at first relapse. The opportunity for durable response and broad age range eligibility makes a strong case for CAR T cells to be used as third-line therapy. The remainder of the agents discussed can be useful in specific clinical scenarios including in patients who are not candidates for ASCT or CAR T cells, as bridging therapy to CAR T cells, or in the r/r setting after CAR T cell therapy failure.

Investigational immunotherapy targeting CD19 for the treatment of acute lymphoblastic leukemia

INTRODUCTION

The anti-CD19 immunotherapy for the treatment of B-precursor acute lymphoblastic leukemia (B-ALL) underwent an expansion in the last decade. CD19 is widely expressed on B-ALL and nearly ideal for immunotherapy because of strong 'on target' ─ but manageable 'off target' effects.

AREAS COVERED

We review the major advances in the field, including data on CD19 monoclonal antibodies, antibody-drug conjugates, bispecific T-cell engaging antibodies and adoptive cellular therapies such as chimeric antigen receptor T cells (CAR-Ts). We discuss novel strategies on approved anti-CD19 immunotherapies. The focus is on experimental anti-CD19 antibodies or CAR-Ts, which might overcome the limitations of toxicity, rapid clearance or resistance.

EXPERT OPINION

The potential of new anti-CD19 antibodies in ALL is limited. The most promising results were achieved with novel cellular constructs. Bi- or multi-specific CAR-Ts might overcome the immune escape by antigen loss. Modified constructs with lower peak expansion or longer persistence provide better control of the toxicity and might improve the efficacy. Finally, the allogeneic 'off the shelf' constructs from healthy donors avoid the time-consuming preparation and the exhaustion of immune cells.

Advances in chimeric antigen receptor T-cell therapy for B-cell non-Hodgkin lymphoma

B-cell non-Hodgkin lymphoma (B-NHL) is a group of heterogeneous disease which remains incurable despite developments of standard chemotherapy regimens and new therapeutic agents in decades. Some individuals could have promising response to standard therapy while others are unresponsive to standard chemotherapy or relapse after autologous hematopoietic stem-cell transplantation (ASCT), which indicates the necessity to develop novel therapies for refractory or relapsed B-NHLs. In recent years, a novel cell therapy, chimeric antigen receptor T-cell therapy (CAR-T), was invented to overcome the limitation of traditional treatments. Patients with aggressive B-NHL are considered for CAR-T cell therapy when they have progressive lymphoma after second-line chemotherapy, relapse after ASCT, or require a third-line therapy. Clinical trials of anti-CD19 CAR-T cell therapy have manifested encouraging efficacy in refractory or relapsed B-NHL. However, adverse effects of this cellular therapy including cytokine release syndrome, neurotoxicity, tumor lysis syndrome and on-target, off-tumor toxicities should attract our enough attention despite the great anti-tumor effects of CAR-T cell therapy. Although CAR-T cell therapy has shown remarkable results in patients with B-NHL, the outcomes of patients with B-NHL were inferior to patients with acute lymphoblastic leukemia. The inferior response rate may be associated with physical barrier of lymphoma, tumor microenvironment and low quality of CAR-T cells manufactured from B-NHL patients. Besides, some patients relapsed after anti-CD19 CAR-T cell therapy, which possibly were due to limited CAR-T cells persistence, CD19 antigen escape or antigen down-regulation. Quite a few new antigen-targeted CAR-T products and new-generation CAR-T, for example, CD20-targeted CAR-T, CD79b-targeted CAR-T, CD37-targeted CAR-T, multi-antigen-targeted CAR-T, armored CAR-T and four-generation CAR-T are developing rapidly to figure out these deficiencies.

Spacer Length Modification Facilitates Discrimination between Normal and Neoplastic Cells and Provides Clinically Relevant CD37 CAR T Cells

Despite the remarkable initial efficacy of CD19 chimeric Ag receptor T (CAR-T) cell therapy, a high incidence of relapse has been observed. To further increase treatment efficacy and reduce the rate of escape of Ag-negative cells, we need to develop CAR-T cells that target other Ags. Given its restricted expression pattern, CD37 was considered a preferred novel target for immunotherapy in hematopoietic malignancies. Therefore, we designed a CD37-targeting CAR-T (CD37CAR-T) using the single-chain variable fragment of a humanized anti-CD37 Ab, transmembrane and intracellular domains of CD28, and CD3ζ signaling domains. High levels of CD37 expression were confirmed in B cells from human peripheral blood and bone marrow B cell precursors at late developmental stages; by contrast, more limited expression of CD37 was observed in early precursor B cells. Furthermore, we found that human CD37CAR-T cells with longer spacer lengths exhibited high gene transduction efficacy but reduced capacity to proliferate; this may be due to overactivation and fratricide. Spacer length optimization resulted in a modest transduction efficiency together with robust capacity to proliferate. CD37CAR-T cells with optimized spacer length efficiently targeted various CD37⁺ human tumor cell lines but had no impact on normal leukocytes both in vitro and in vivo. CD37CAR-T cells effectively eradicated Raji cells in xenograft model. Collectively, these results suggested that spacer-optimized CD37CAR-T cells could target CD37-high neoplastic B cells both in vitro and in vivo, with only limited interactions with their normal leukocyte lineages, thereby providing an additional promising therapeutic intervention for patients with B cell malignancies.

Vγ9Vδ2 T Cells Concurrently Kill Cancer Cells and Cross-Present Tumor Antigens

The human Vγ9Vδ2 T cell is a unique cell type that holds great potential in immunotherapy of cancer. In particular, the therapeutic potential of this cell type in adoptive cell therapy (ACT) has gained interest. In this regard optimization of in vitro expansion methods and functional characterization is desirable. We show that Vγ9Vδ2 T cells, expanded in vitro with zoledronic acid (Zometa or ZOL) and Interleukin-2 (IL-2), are efficient cancer cell killers with a trend towards increased killing efficacy after prolonged expansion time. Thus, Vγ9Vδ2 T cells expanded for 25 days in vitro killed prostate cancer cells more efficiently than Vγ9Vδ2 T cells expanded for 9 days. These data are supported by phenotype characteristics, showing increased expression of CD56 and NKG2D over time, reaching above 90% positive cells after 25 days of expansion. At the early stage of expansion, we demonstrate that Vγ9Vδ2 T cells are capable of cross-presenting tumor antigens. In this regard, our data show that Vγ9Vδ2 T cells can take up tumor-associated antigens (TAA) gp100, MART-1 and MAGE-A3 - either as long peptide or recombinant protein - and then present TAA-derived peptides on the cell surface in the context of HLA class I molecules, demonstrated by their recognition as targets by peptide-specific CD8 T cells. Importantly, we show that cross-presentation is impaired by the proteasome inhibitor lactacystin. In conclusion, our data indicate that Vγ9Vδ2 T cells are broadly tumor-specific killers with the additional ability to cross-present MHC class I-restricted peptides, thereby inducing or supporting tumor-specific αβTCR CD8 T cell responses. The dual functionality is dynamic during in vitro expansion, yet, both functions are of interest to explore in ACT for cancer therapy.

A BCMAxCD3 bispecific T cell-engaging antibody demonstrates robust antitumor efficacy similar to that of anti-BCMA CAR T cells

CD3-engaging bispecific antibodies (bsAbs) and chimeric antigen receptor (CAR) T cells are potent therapeutic approaches for redirecting patient T cells to recognize and kill tumors. Here we describe a fully human bsAb (REGN5458) that binds to B-cell maturation antigen (BCMA) and CD3, and compare its antitumor activities vs those of anti-BCMA CAR T cells to identify differences in efficacy and mechanism of action. In vitro, BCMAxCD3 bsAb efficiently induced polyclonal T-cell killing of primary human plasma cells and multiple myeloma (MM) cell lines expressing a range of BCMA cell surface densities. In vivo, BCMAxCD3 bsAb suppressed the growth of human MM tumors in murine xenogeneic models and showed potent combinatorial efficacy with programmed cell death protein 1 blockade. BCMAxCD3 bsAb administration to cynomolgus monkeys was well tolerated, resulting in the depletion of BCMA+ cells and mild inflammatory responses characterized by transient increases in C-reactive protein and serum cytokines. The antitumor efficacy of BCMAxCD3 bsAb was compared with BCMA-specific CAR T cells containing a BCMA-binding single-chain variable fragment derived from REGN5458. Both BCMAxCD3 bsAb and anti-BCMA CAR T cells showed similar targeted cytotoxicity of MM cell lines and primary MM cells in vitro. In head-to-head in vivo studies, BCMAxCD3 bsAb rapidly cleared established systemic MM tumors, whereas CAR T cells cleared tumors with slower kinetics. Thus, using the same BCMA-binding domain, these results suggest that BCMAxCD3 bsAb rapidly exerts its therapeutic effects by engaging T cells already in place at the tumor site, whereas anti-BCMA CAR T cells require time to traffic to the tumor site, activate, and numerically expand before exerting antitumor effects.

Composite CD79A/CD40 co-stimulatory endodomain enhances CD19CAR-T cell proliferation and survival

Adoptively transferred CD19 chimeric antigen receptor (CAR) T cells have led to impressive clinical outcomes in B cell malignancies. Beyond induction of remission, the persistence of CAR-T cells is required to prevent relapse and provide long-term disease control. To improve CAR-T cell function and persistence, we developed a composite co-stimulatory domain of a B cell signaling moiety, CD79A/CD40, to induce a nuclear translocating signal, NF-κB, to synergize with other T cell signals and improve CAR-T cell function. CD79A/CD40 incorporating CD19CAR-T cells (CD19.79a.40z) exhibited higher NF-κB and p38 activity upon CD19 antigen exposure compared with the CD28 or 4-1BB incorporating CD19CAR-T cells (CD19.28z and CD19.BBz). Notably, we found that CD19.79a.40z CAR-T cells continued to suppress CD19⁺ target cells throughout the co-culture assay, whereas a tendency for tumor growth was observed with CD19.28z CAR-T cells. Moreover, CD19.79a.40z CAR-T cells exhibited robust T cell proliferation after culturing with CD19⁺ target cells, regardless of exogenous interleukin-2. In terms of in vivo efficiency, CD19.79a.40z demonstrated superior anti-tumor activity and in vivo CAR-T cell proliferation compared with CD19.28z and CD19.BBz CD19CAR-T cells in Raji-inoculated mice. Our data demonstrate that the CD79A/CD40 co-stimulatory domain endows CAR-T cells with enhanced proliferative capacity and improved anti-tumor efficacy in a murine model.

The Transferrin Receptor-Directed CAR for the Therapy of Hematologic Malignancies

As many patients ultimately relapse after chimeric antigen receptor (CAR) T-cell therapy, identification of alternative targets is currently being evaluated. Substantial research efforts are underway to develop new targets. The transferrin receptor (TfR) is prevalently expressed on rapidly proliferating tumor cells and holds the potential to be the alternative target. In order to investigate the efficacy and challenges of TfR-targeting on the CAR-based therapy strategy, we generated a TfR-specific CAR and established the TfR-CAR–modified T cells. To take the advantage of TfR being widely shared by multiple tumors, TfR-CAR T cells were assessed against several TfR⁺ hematological malignant cell lines. Data showed that TfR-CAR T cells were powerfully potent in killing all these types of cells in vitro and in killing T-ALL cells in vivo. These findings suggest that TfR could be a universal target to broaden and improve the therapeutic efficacy of CAR T cells and warrant further efforts to use these cells as an alternative CAR T cell product for the therapy of hematological malignancies.

Anti-CD19 mAb modified mesoporous titanium dioxide as exclusively targeting vector for efficient B-lymphoblastic leukemia therapy

B lymphoblastic leukemia (B-LL) is a clonal hematopoietic stem cell neoplasm derived from B-cell progenitors, which mainly occurs in children and adolescents and is one of the main causes of death from malignant tumors in this population. The surface marker CD19 is specifically expressed on the membrane of most malignant B-cells, which is widely used as a marker of B-LL antigen-specific immunotherapy. In this study, mesoporous titanium dioxide nanoparticles (MTNs)-based antibody drug delivery system was designed for B-LL treatment. Anti-CD19 monoclonal antibody was conjugated to PEGylated MTNs, and doxorubicin (DOX) was loaded in the nanoparticle. The CD19-PEG-MTN/DOX nanoparticle could recognize CD19⁺B-LL cell lines and induced them apoptosis, but nontoxic for the normal cells. Further, after treated with CD19-PEG-MTN/DOX nanoparticle, pro-apoptotic proteins Bax and Caspase-3 in KOPN 8 and NALM-6 cells were significantly upregulated, but anti-apoptotic proteins Bcl2, MCL-1, HSP 70, and BAG 3 were downregulated, which indicated the activation of the apoptosis pathway by the nanodrug. By contrast, CD19-PEG-MTN/DOX didn't play a part on CD19^-cell line U937. Besides, the cytotoxicity of CD19-PEG-MTN/DOX was low with good biocompatibility. Collectively, CD19-PEG-MTN/DOX is a promising antitumor nanodrug for the treatment of B-LL.

Emerging molecular subtypes and therapeutic targets in B-cell precursor acute lymphoblastic leukemia

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is characterized by genetic alterations with high heterogeneity. Precise subtypes with distinct genomic and/or gene expression patterns have been recently revealed using high-throughput sequencing technology. Most of these profiles are associated with recurrent non-overlapping rearrangements or hotspot point mutations that are analogous to the established subtypes, such as DUX4 rearrangements, MEF2D rearrangements, ZNF384/ZNF362 rearrangements, NUTM1 rearrangements, BCL2/MYC and/or BCL6 rearrangements, ETV6-RUNX1-like gene expression, PAX5alt (diverse PAX5 alterations, including rearrangements, intragenic amplifications, or mutations), and hotspot mutations PAX5 (p.Pro80Arg) with biallelic PAX5 alterations, IKZF1 (p.Asn159Tyr), and ZEB2 (p.His1038Arg). These molecular subtypes could be classified by gene expression patterns with RNA-seq technology. Refined molecular classification greatly improved the treatment strategy. Multiagent therapy regimens, including target inhibitors (e.g., imatinib), immunomodulators, monoclonal antibodies, and chimeric antigen receptor T-cell (CAR-T) therapy, are transforming the clinical practice from chemotherapy drugs to personalized medicine in the field of risk-directed disease management. We provide an update on our knowledge of emerging molecular subtypes and therapeutic targets in BCP-ALL.

Promising genes and variants to reduce chemotherapy adverse effects in acute lymphoblastic leukemia

Almost two decades ago, the sequencing of the human genome and high throughput technologies came to revolutionize the clinical and therapeutic approaches of patients with complex human diseases. In acute lymphoblastic leukemia (ALL), the most frequent childhood malignancy, these technologies have enabled to characterize the genomic landscape of the disease and have significantly improved the survival rates of ALL patients. Despite this, adverse reactions from treatment such as toxicity, drug resistance and secondary tumors formation are still serious consequences of chemotherapy, and the main obstacles to reduce ALL-related mortality. It is well known that germline variants and somatic mutations in genes involved in drug metabolism impact the efficacy of drugs used in oncohematological diseases therapy. So far, a broader spectrum of clinically actionable alterations that seems to be crucial for the progression and treatment response have been identified. Although these results are promising, it is necessary to put this knowledge into the clinics to help physician make medical decisions and generate an impact in patients' health. This review summarizes the gene variants and clinically actionable mutations that modify the efficacy of antileukemic drugs. Therefore, knowing their genetic status before treatment is critical to reduce severe adverse effects, toxicities and life-threatening consequences in ALL patients.

Outcomes and factors impacting use of axicabtagene ciloleucel in patients with relapsed or refractory large B-cell lymphoma: results from an intention-to-treat analysis

Data on real-world outcomes of axicabtagene ciloleucel (axi-cel) therapy for relapsed/refractory large B-cell lymphoma (R/R LBCL) are limited. In this intent to treat (ITT) analysis, we reviewed records of 38 consecutive patients with R/R LBCL for whom axi-cel was intended. Twenty-seven (71%) patients received axi-cel and 11 (29%) did not. Patients in the non-axi-cel group had a higher hematopoietic cell transplantation comorbidity index (HCT-CI) (median 4 vs. 2, p = .04). Median overall survival for the ITT, axi-cel and non-axi-cel group was 10 (95% CI, 3.7 to 13), 13 (95% CI, 7.7 to N.R.) and 1 (95% CI, 0.4 to 3.7) month(s) respectively. Factors limiting axi-cel use were disease progression, sepsis, manufacturing failure and socioeconomic barrier in 6 (55%), 3 (27%), 1 (9%) and 1 (9%) patient(s) respectively. Additional strategies are needed to ensure all LBCL patients for whom chimeric antigen receptor (CAR) T-cell therapy is prescribed can receive this treatment.

[Quality assessment of CAR T-cell activity: Recommendations of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

CAR T-cells are anti-cancer immunocellular therapy drugs that involve reprogramming the patient's T-cells using a transgene encoding a chimeric antigen receptor (CAR). Although CAR T-cells are cellular therapies, the organization for manufacturing and delivering these medicinal products is in many ways different from the one for hematopoietic cell grafts or donor lymphocyte infusions. The implementation of this innovative therapy is recent and requires close coordination between clinical teams, the therapeutic apheresis unit, the cell therapy unit, the pharmaceutical laboratory, and pharmacy. Apart from the regulatory texts, which are regularly modified, and the specific requirements of each pharmaceutical laboratory, there is currently no guide to help the centers initiating their activity and there is no specific indicator to assess the quality of the CAR T-cell activity in each center. The purpose of the current harmonization workshop is to clarify the regulatory prerequisites warranted for a center to have a CAR T-cell activity and to propose recommendations for implementing quality tools, in particular indicators, and allowing their sharing.

Facts and Challenges in Immunotherapy for T-Cell Acute Lymphoblastic Leukemia

T-cell acute lymphoblastic leukemia (T-ALL), a T-cell malignant disease that mainly affects children, is still a medical challenge, especially for refractory patients for whom therapeutic options are scarce. Recent advances in immunotherapy for B-cell malignancies based on increasingly efficacious monoclonal antibodies (mAbs) and chimeric antigen receptors (CARs) have been encouraging for non-responding or relapsing patients suffering from other aggressive cancers like T-ALL. However, secondary life-threatening T-cell immunodeficiency due to shared expression of targeted antigens by healthy and malignant T cells is a main drawback of mAb—or CAR-based immunotherapies for T-ALL and other T-cell malignancies. This review provides a comprehensive update on the different immunotherapeutic strategies that are being currently applied to T-ALL. We highlight recent progress on the identification of new potential targets showing promising preclinical results and discuss current challenges and opportunities for developing novel safe and efficacious immunotherapies for T-ALL.

Endothelial, pericyte and tumor cell expression in glioblastoma identifies fibroblast activation protein (FAP) as an excellent target for immunotherapy

Objectives

Targeted immunotherapies such as chimeric antigen receptor (CAR)-T cells are emerging as attractive treatment options for glioblastoma, but rely on identification of a suitable tumor antigen. We validated a new target antigen for glioblastoma, fibroblast activation protein (FAP), by undertaking a detailed expression study of human samples.

Methods

Glioblastoma and normal tissues were assessed using immunostaining, supported by analyses of published transcriptomic datasets. Short-term cultures of glioma neural stem (GNS) cells were compared to cultures of healthy astrocytes and neurons using flow cytometry. Glioblastoma tissues were dissociated and analysed by high-parameter flow cytometry and single-cell transcriptomics (scRNAseq).

Results

Compared to normal brain, FAP was overexpressed at the gene and protein level in a large percentage of glioblastoma tissues, with highest levels of expression associated with poorer prognosis. FAP was also overexpressed in several paediatric brain cancers. FAP was commonly expressed by cultured GNS cells but absent from normal neurons and astrocytes. Within glioblastoma tissues, the strongest expression of FAP was around blood vessels. In fact, almost every tumor vessel was highlighted by FAP expression, whereas normal tissue vessels and cultured endothelial cells (ECs) lacked expression. Single-cell analyses of dissociated tumors facilitated a detailed characterisation of the main cellular components of the glioblastoma microenvironment and revealed that vessel-localised FAP is because of expression on both ECs and pericytes.

Conclusion

Fibroblast activation protein is expressed by multiple cell types within glioblastoma, highlighting it as an ideal immunotherapy antigen to target destruction of both tumor cells and their supporting vascular network.

Treatment of Multiple Myeloma Using Chimeric Antigen Receptor T Cells with Dual Specificity

Chimeric antigen receptor (CAR) T-cell therapy has shown remarkable successes in fighting B-cell leukemias/lymphomas. Promising response rates are reported in patients treated with B-cell maturation antigen (BCMA) CAR T cells for multiple myeloma. However, responses appear to be nondurable, highlighting the need to expand the repertoire of multiple myeloma-specific targets for immunotherapy and to generate new CAR T cells. Here, we developed a "dual-CAR" targeting two multiple myeloma-associated antigens and explored its safety and efficacy. To reduce the "off-target" toxicity, we used the recognition of paired antigens that were coexpressed by the tumor to induce efficient CAR T-cell activation. The dual-CAR construct presented here was carefully designed to target the multiple myeloma-associated antigens, taking into consideration the distribution of both antigens on normal human tissues. Our results showed that the CD138/CD38-targeted dual CAR (dCAR138-38) elicited a potent anti-multiple myeloma response both in vitro and in vivo NSG mice transplanted with a multiple myeloma cell line and treated with dCAR138-38 showed median survival of 97 days compared with 31 days in the control group treated with mock-lymphocytes. The dCAR138-38 showed increased specificity toward cells expressing both targeted antigens compared with single-antigen-expressing cells and low activity toward primary cells from healthy tissues. Our findings indicated that the dCAR138-38 may provide a potent and safe alternative therapy for patients with multiple myeloma.

Immunotherapy in Pediatric B-Cell Acute Lymphoblastic Leukemia: Advances and Ongoing Challenges

Leukemia, most commonly B-cell acute lymphoblastic leukemia (B-ALL), accounts for about 30% of childhood cancer diagnoses. While there have been dramatic improvements in childhood ALL outcomes, certain subgroups-particularly those who relapse-fare poorly. In addition, cure is associated with significant short- and long-term side effects. Given these challenges, there is great interest in novel, targeted approaches to therapy. A number of new immunotherapeutic agents have proven to be efficacious in relapsed or refractory disease and are now being investigated in frontline treatment regimens. Blinatumomab (a bispecific T-cell engager that targets cluster of differentiation [CD]-19) and inotuzumab ozogamicin (a humanized antibody-drug conjugate to CD22) have shown the most promise. Chimeric antigen receptor T (CAR-T) cells, a form of adoptive immunotherapy, rely on the transfer of genetically modified effector T cells that have the potential to persist in vivo for years, providing ongoing long-term disease control. In this article, we discuss the clinical biology and treatment of B-ALL with an emphasis on the role of immunotherapy in overcoming the challenges of conventional cytotoxic therapy. As immunotherapy continues to move into the frontline of pediatric B-ALL therapy, we also discuss strategies to address unique side effects associated with these agents and efforts to overcome mechanisms of resistance to immunotherapy.

Adapter chimeric antigen receptor (AdCAR)-engineered NK-92 cells: an off-the-shelf cellular therapeutic for universal tumor targeting

Despite the recent success of CAR T cells targeting CD19 and CD22 in hematological malignancies, the production of CAR T cells still requires an extensive manufacturing process. The well-established NK-92 cell line provides a promising alternative to produce CAR-modified effector cells in a GMP-compliant, cost-effective way. NK-92 can be redirected against a variety of surface antigens by our adapter CAR (AdCAR) system utilizing biotinylated antibodies (bAb) as adapter molecules. Selected bAb were capable of inducing significant AdCAR NK-92-mediated lysis of non-Hodgkin lymphoma (NHL) and mantle-cell lymphoma (MCL) cell lines as well as primary MCL and chronic lymphocytic leukemia (CLL) cells. AdCAR specificity was proven using a JeKo-1 CD19/CD20 knockout antigen-loss model. Moreover, through combinations of bAb, AdCAR NK-92 cells are capable of combatting tumor antigen evasion mechanisms. In conclusion, we successfully generated the AdCAR NK-92 cell line which can be manufactured as an “off-the-shelf, on-demand” product allowing universal and tunable tumor targeting.

Mantle cell lymphoma: insights into therapeutic targets at the preclinical level

INTRODUCTION

Mantle cell lymphoma (MCL) is a chronically relapsing B-cell non-Hodgkin lymphoma characterized by recurrent molecular-cytogenetic aberrations that lead to deregulation of DNA damage response, cell cycle progression, epigenetics, apoptosis, proliferation, and motility. In the last 10 years, clinical approval of several innovative drugs dramatically changed the landscape of treatment options in the relapsed/refractory (R/R) MCL, which translated into significantly improved survival parameters.

AREAS COVERED

Here, up-to-date knowledge on the biology of MCL together with currently approved and clinically tested frontline and salvage therapies are reviewed. In addition, novel therapeutic targets in MCL based on the scientific reports published in Pubmed are discussed.

EXPERT OPINION

Bruton tyrosine-kinase inhibitors, NFkappaB inhibitors, BCL2 inhibitors, and immunomodulary agents in combination with monoclonal antibodies and genotoxic drugs have the potential to induce long-term remissions in majority of newly diagnosed MCL patients. Several other classes of anti-tumor drugs including phosphoinositole-3-kinase, cyclin-dependent kinase or DNA damage response kinase inhibitors have demonstrated promising anti-lymphoma efficacy in R/R MCL. Most importantly, adoptive immunotherapy with genetically modified T-cells carrying chimeric antigen receptor represents a potentially curative treatment approach even in the patients with chemotherapy and ibrutinib-refractory disease.

Automated Manufacture of Autologous CD19 CAR-T Cells for Treatment of Non-hodgkin Lymphoma

Chimeric antigen receptor T cells (CAR-T cell) targeting CD19 are effective against several subtypes of CD19-expressing hematologic malignancies. Centralized manufacturing has allowed rapid expansion of this cellular therapy, but it may be associated with treatment delays due to the required logistics. We hypothesized that point of care manufacturing of CAR-T cells on the automated CliniMACS Prodigy® device allows reproducible and fast delivery of cells for the treatment of patients with non-Hodgkin lymphoma. Here we describe cell manufacturing results and characterize the phenotype and effector function of CAR-T cells used in a phase I/II study. We utilized a lentiviral vector delivering a second-generation CD19 CAR construct with 4-1BB costimulatory domain and TNFRSF19 transmembrane domain. Our data highlight the successful generation of CAR-T cells at numbers sufficient for all patients treated, a shortened duration of production from 12 to 8 days followed by fresh infusion into patients, and the detection of CAR-T cells in patient circulation up to 1-year post-infusion.

CAR T-cell treatment during the COVID-19 pandemic: Management strategies and challenges

The pandemic of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is spreading rapidly across the world. Currently, the COVID-19 pandemic is affecting the continuity of essential routine healthcare services and procedures, including chimeric antigen receptor T-cell (CAR-T) therapy, a life-saving option for patients with relapsed/refractory (R/R) hematologic malignancies. Due to the rapid disease progression of hematological malignancies, there is an urgent need to manufacture and utilize CAR T-cells. However, CAR-T treatment has become extraordinarily challenging during this COVID-19 pandemic. Thus, many medical and technical factors must now be taken into consideration before, during, and after CAR-T therapy. The purpose of this review is to provide brief suggestions for rational decision-making strategies in evaluating and selecting CAR T-cell treatment and appropriate CAR T-cell products, and protective strategies for medical staff and patients to prevent infection in the midst of the current COVID-19 pandemic.

Applying Antibodies Inside Cells: Principles and Recent Advances in Neurobiology, Virology and Oncology

To interfere with cell function, many scientists rely on methods that target DNA or RNA due to the ease with which they can be applied. Proteins are usually the final executors of function but are targeted only indirectly by these methods. Recent advances in targeted degradation of proteins based on proteolysis-targeting chimaeras (PROTACs), ubiquibodies, deGradFP (degrade Green Fluorescent Protein) and other approaches have demonstrated the potential of interfering directly at the protein level for research and therapy. Proteins can be targeted directly and very specifically by antibodies, but using antibodies inside cells has so far been considered to be challenging. However, it is possible to deliver antibodies or other proteins into the cytosol using standard laboratory equipment. Physical methods such as electroporation have been demonstrated to be efficient and validated thoroughly over time. The expression of intracellular antibodies (intrabodies) inside cells is another way to interfere with intracellular targets at the protein level. Methodological strategies to target the inside of cells with antibodies, including delivered antibodies and expressed antibodies, as well as applications in the research areas of neurobiology, viral infections and oncology, are reviewed here. Antibodies have already been used to interfere with a wide range of intracellular targets. Disease-related targets included proteins associated with neurodegenerative diseases such as Parkinson's disease (α-synuclein), Alzheimer's disease (amyloid-β) or Huntington's disease (mutant huntingtin [mHtt]). The applications of intrabodies in the context of viral infections include targeting proteins associated with HIV (e.g. HIV1-TAT, Rev, Vif, gp41, gp120, gp160) and different oncoviruses such as human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV) and Epstein-Barr virus, and they have been used to interfere with various targets related to different processes in cancer, including oncogenic pathways, proliferation, cell cycle, apoptosis, metastasis, angiogenesis or neo-antigens (e.g. p53, human epidermal growth factor receptor-2 [HER2], signal transducer and activator of transcription 3 [STAT3], RAS-related RHO-GTPase B (RHOB), cortactin, vascular endothelial growth factor receptor 2 [VEGFR2], Ras, Bcr-Abl). Interfering at the protein level allows questions to be addressed that may remain unanswered using alternative methods. This review addresses why direct targeting of proteins allows unique insights, what is currently feasible in vitro, and how this relates to potential therapeutic applications.

Allogeneic haematopoietic stem cell transplantation improves outcome of adults with relapsed/refractory Philadelphia chromosome-positive acute lymphoblastic leukemia entering remission following CD19 chimeric antigen receptor T cells

Relapsed/refractory Philadelphia chromosome-positive acute lymphoblastic leukemia (r/r Ph+ ALL) has an extremely poor prognosis. Chimeric antigen receptor T-cell (CART) therapy has acquired unprecedented efficacy in B-cell malignancies, but its role in the long-term survival of r/r Ph+ ALL patients is unclear. We analyzed the effect of CART on 56 adults with r/r Ph+ ALL who accepted split doses of humanized CD19-targeted CART after lymphodepleting chemotherapy. 51/56 (91.1%) achieved complete remission (CR) or CR with inadequate count recovery (CRi), including 38 patients with negative minimal residual disease (MRD) tested by bone marrow BCR-ABL1 copies. Subsequently, 30/51 CR/CRi patients accepted consolidative allogeneic haematopoietic stem cell transplantation (alloHSCT). Their outcomes were compared with those of 21/51 contemporaneous patients without alloHSCT. The 2-year overall survival (OS) and leukemia-free survival (LFS) of CR/CRi patients with alloHSCT were significantly superior to those without alloHSCT (58.9%, CI 49.8-68.0% vs. 22.7%, CI 12.7-32.7%, p = 0.005; 53.2%, CI 43.6-62.8% vs. 18.8%, CI 9.2-28.4%, p = 0.000, respectively). Multivariate analysis revealed that alloHSCT and MRD-negative post-CART were the independent prognostic factors for OS and LFS. CART therapy is highly effective for r/r Ph+ ALL patients, and consolidative alloHSCT could prolong their OS and LFS.

Successful treatment of acute B lymphoblastic leukemia relapse in the skin and testicle by anti-CD19 CAR-T with IL-6 knocking down: a case report

Background

Extramedullary relapse is an important cause of treatment failure among patients with acute lymphoblastic leukemia (ALL). This type of relapse is commonly observed in the central nervous system, while it is rare in the testicles and skin. Chimeric antigen receptor-modified T cell (CAR-T) therapy targeting CD19 has shown to be a beneficial treatment approach for relapsed/refractory B cell acute lymphoblasticleukemia (r/r B-ALL). Yet, few studies have reported data regarding the treatment of extramedullary B-ALL relapse, especially both in skin and testicle, with CAR-T therapy.

Case presentation

Here we reported a single case of a patient with relapsed B-ALL in skin and testicle who was successfully treated by the shRNA-IL6-modified anti-CD19 CAR-T(ssCAR-T-19) therapy. A 29-year-old man with relapsed B-ALL in skin and testicle was enrolled in clinal trial involving the shRNA-IL6-modified anti-CD19 CAR-T(ssCAR-T-19) therapy (ClinicalTrials.gov number, NCT03919240). The patient had toxicity consistent with the grade 1 cytokine release syndrome.

Conclusions

ssCART-19 therapy may be used to effectively eliminate infiltrating leukemia cells in the skin and testicle with mild toxicity, which could be a much safer approach to bridge allo-HSCT, thus further improving the patient’s outcome.

Trial registration

ClinicalTrials.gov number, NCT03919240, Registered 18 April 2019, retrospectively registered.

Acute Kidney Injury after CAR-T Cell Therapy: Low Incidence and Rapid Recovery

Chimeric antigen receptor (CAR) T cell therapy using engineered cytotoxic T cells has shown promising responses in various hematologic malignancies. Cytokine release syndrome (CRS) and immune effector cell-associated neurologic syndrome (ICANS) are recognized toxicities of CAR-T, whereas kidney injury remains less well recognized. The objective of the present study was to identify the incidence of acute kidney injury (AKI) after CAR-T cell therapy, potential risk factors, and recovery of kidney function. We performed a retrospective review of 46 adult patients with non-Hodgkin lymphoma treated with CAR-T therapy between February 2018 and February 2019 at our institution. Serum creatinine values before CAR-T therapy through day 100 were used to assess AKI, as defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria: grade 1, 1.5- to <2-fold of baseline; grade 2, 2- to <3-fold of baseline; grade 3, ≥3-fold of baseline. CRS and ICANS were graded using the consensus criteria of the American Society of Transplantation and Cellular Therapy. The overall incidence of CRS was 78.3% (95% confidence interval [CI], 66% to 90.5%), of whom 13% (95% CI, 3.3% to 22.8%) developed grade 3-4 CRS, whereas the overall incidence of ICANS was lower at 45.7% (95% CI, 3.1% to 60.3%). The cumulative incidence of any grade AKI by day 100 was 30% (95% CI, 16.9% to 43.9%), with a grade 1 AKI incidence of 21.7% (95% CI, 9.7% to 33.8%) and a grade 2-3 AKI incidence of 8.7% (95% CI, .4% to 17%). No patients developed severe AKI necessitating renal replacement therapy. Patients with previous autologous or allogeneic stem cell transplantation, those requiring intensive care unit level care and with grade 3-4 CRS had a higher incidence of AKI. Most patients recovered, with kidney function returning to baseline within 30 days. We conclude that with early recognition and management of CAR-T complications, the incidence of AKI is low, the severity of injury is mild, and most patients recover kidney function within 30 days.

Impact and Intricacies of Bone Marrow Microenvironment in B-cell Lymphomas: From Biology to Therapy

Lymphoma, a group of widely prevalent hematological malignancies of lymphocyte origin, has become the focus of significant clinical research due to their high propensity for refractory/relapsed (R/R) disease, leading to poor prognostic outcomes. The complex molecular circuitry in lymphomas, especially in the aggressive phenotypes, has made it difficult to find a therapeutic option that can salvage R/R disease. Furthermore, the association of lymphomas with the Bone Marrow (BM) microenvironment has been found to portend worse outcomes in terms of heightened chances of relapse and acquired resistance to chemotherapy. This review assesses the current therapy options in three distinct types of lymphomas: diffuse large B-cell lymphoma, follicular lymphoma and mantle cell lymphoma. It also explores the role of the BM tumor microenvironment as a secure 'niche' for lymphoma cells to grow, proliferate and survive. It further evaluates potential mechanisms through which the tumor cells can establish molecular connections with the BM cells to provide pro-tumor benefits, and discusses putative therapeutic strategies for disrupting the BM-lymphoma cell communication.