CD19-targeted chimeric antigen receptor T-cell therapy for acute lymphoblastic leukemia

Use of CAR T-cell for acute lymphoblastic leukemia (ALL) treatment: a review study

Acute lymphoblastic leukemia (ALL) is a cancer-specific lymphoid cell. Induction and consolidation chemotherapy alone or in combination with different therapeutic approaches remain the main treatment. Although complete or partial remission of the disease can be achieved, the risk of relapse or refractory leukemia is still high. More effective and safe therapy options are yet unmet needs. In recent years' new therapeutic approaches have been widely used. Hematopoietic Stem Cell Transplantation (HSCT) presents significant limitations and the outcome of the consolidation treatment is patient dependent. Side effects such as Graft versus Host Disease (GvHD) in allogeneic hematopoietic stem cell transplantation are extremely common, therefore, using alternative methods to address these challenges for treatment seems crucial. In the last decade, T cells genetically engineered with Chimeric Antigen Receptor (CAR) treatment for the ALL are largely studied and represent the new era of strategy. According to the Phase I/II clinical trials, this technology results seem very promising and can be used in the next future as an effective and safe treatment for ALL treatment. In this review different generations, challenges, and clinical studies related to chimeric antigen receptor (CAR) T-cells for ALL treatment are discussed.

The safety of blinatumomab in pediatric patients with acute lymphoblastic leukemia: A systematic review and meta-analysis

BACKGROUND

Blinatumomab is a bispecific CD19-directed CD3 T-cell engager that has proven efficacy in children with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). Despite its efficacy, it has also been associated with the development of potentially serious adverse events such as the cytokine release syndrome (CRS) and neurologic events. The present meta-analysis aimed to assess the safety profile of blinatumomab in terms of serious adverse events, CRS, and neurologic events (such as seizure and encephalopathy) in pediatric patients with B-cell ALL.

METHODS AND FINDINGS

A systematic review was conducted in Pubmed up to December 10, 2021 to retain pediatric clinical trials on blinatumomab. A random effect meta-analysis approach was used. This study followed the PRISMA statement. Four out of the 255 initial references were selected, of which 2 were phase 1/2 clinical trials and 2 phase 3 clinical trials. Blinatumomab was associated with a lower risk of serious adverse events (Risk ratio RR, 0.56; 95% CI, 0.32-0.99), febrile neutropenia (RR, 0.13; 95% CI, 0.06-0.26), infection (RR, 0.40; 95% CI, 0.29-0.56), and grade ≥ 3 adverse events (RR, 0.79; 95% CI, 0.67-0.93) compared to chemotherapy. No difference in the risk of CRS (RR, 8.37; 95% CI, 0.27-260.97) and seizure (RR, 6.43; 95% CI, 0.79-53.08) was observed between groups, while for encephalopathy a higher risk was associated with blinatumomab compared to chemotherapy (RR, 8.90; 95% CI, 1.08-73.29).

CONCLUSION

Our data support the good safety profile of bliantumomab in treating pediatric patients with B-ALL.

The Role of the Tumor Microenvironment and Treatment Strategies in Colorectal Cancer

Colorectal cancer (CRC) has the second highest mortality rate among all cancers worldwide. Surgery, chemotherapy, radiotherapy, molecular targeting and other treatment methods have significantly prolonged the survival of patients with CRC. Recently, the emergence of tumor immunotherapy represented by immune checkpoint inhibitors (ICIs) has brought new immunotherapy options for the treatment of advanced CRC. As the efficacy of ICIs is closely related to the tumor immune microenvironment (TME), it is necessary to clarify the relationship between the immune microenvironment of CRC and the efficacy of immunotherapy to ensure that the appropriate drugs are selected. We herein review the latest research progress in the immune microenvironment and strategies related to immunotherapy for CRC. We hope that this review helps in the selection of appropriate treatment strategies for CRC patients.

Emerging Nanoparticle Strategies for Modulating Tumor-Associated Macrophage Polarization

Immunotherapy has made great progress in recent years, yet the efficacy of solid tumors remains far less than expected. One of the main hurdles is to overcome the immune-suppressive tumor microenvironment (TME). Among all cells in TME, tumor-associated macrophages (TAMs) play pivotal roles because of their abundance, multifaceted interactions to adaptive and host immune systems, as well as their context-dependent plasticity. Underlying the highly plastic characteristic, lots of research interests are focused on repolarizing TAMs from M2-like pro-tumor phenotype towards M1-like antitumoral ones. Nanotechnology offers great opportunities for targeting and modulating TAM polarization to mount the therapeutic efficacy in cancer immunotherapy. Here, this mini-review highlights those emerging nano-approaches for TAM repolarization in the last three years.

Humanization of T cell-mediated immunity in mice

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T cell receptor (TCR) signaling in health and disease

Interaction of the T cell receptor (TCR) with an MHC-antigenic peptide complex results in changes at the molecular and cellular levels in T cells. The outside environmental cues are translated into various signal transduction pathways within the cell, which mediate the activation of various genes with the help of specific transcription factors. These signaling networks propagate with the help of various effector enzymes, such as kinases, phosphatases, and phospholipases. Integration of these disparate signal transduction pathways is done with the help of adaptor proteins that are non-enzymatic in function and that serve as a scaffold for various protein-protein interactions. This process aids in connecting the proximal to distal signaling pathways, thereby contributing to the full activation of T cells. This review provides a comprehensive snapshot of the various molecules involved in regulating T cell receptor signaling, covering both enzymes and adaptors, and will discuss their role in human disease.

Targeting Cross-Presentation as a Route to Improve the Efficiency of Peptide-Based Cancer Vaccines

Cross-presenting dendritic cells (DC) offer an attractive target for vaccination due to their unique ability to process exogenous antigens for presentation on MHC class I molecules. Recent reports have established that these DC express unique surface receptors and play a critical role in the initiation of anti-tumor immunity, opening the way for the development of vaccination strategies specifically targeting these cells. This study investigated whether targeting cross-presenting DC by two complementary mechanisms could improve vaccine effectiveness, in both a viral setting and in a murine melanoma model. Our novel vaccine construct contained the XCL1 ligand, to target uptake to XCR1+ cross-presenting DC, and a cell penetrating peptide (CPP) with endosomal escape properties, to enhance antigen delivery into the cross-presentation pathway. Using a prime-boost regimen, we demonstrated robust expansion of antigen-specific T cells following vaccination with our CPP-linked peptide vaccine and protective immunity against HSV-1 skin infection, where vaccine epitopes were natively expressed by the virus. Additionally, our novel vaccination strategy slowed tumor outgrowth in a B16 murine melanoma model, compared to adjuvant only controls, suggesting antigen-specific anti-tumor immunity was generated following vaccination. These findings suggest that novel strategies to target the antigen cross-presentation pathway in DC may be beneficial for the generation of anti-tumor immunity.

Potential of Stem Cells and CART as a Potential Polytherapy for Small Cell Lung Cancer

Despite the increasing urgency of the problem of treating small cell lung cancer (SCLC), information on the causes of its development is fragmentary. There is no complete understanding of the features of antitumor immunity and the role of the microenvironment in the development of SCLC resistance. This impedes the development of new methods for the diagnosis and treatment of SCLC. Lung cancer and chronic obstructive pulmonary disease (COPD) have common pathogenetic factors. COPD is a risk factor for lung cancer including SCLC. Therefore, the search for effective approaches to prevention, diagnosis, and treatment of SCLC in patients with COPD is an urgent task. This review provides information on the etiology and pathogenesis of SCLC, analyses the effectiveness of current treatment options, and critically evaluates the potential of chimeric antigen receptor T cells therapy (CART therapy) in SCLC. Moreover, we discuss potential links between lung cancer and COPD and the role of endothelium in the development of COPD. Finally, we propose a new approach for increasing the efficacy of CART therapy in SCLC.

Intensive monitoring of minimal residual disease and chimerism after allogeneic hematopoietic stem cell transplantation for acute leukemia in children

Posttransplant leukemia detection before overt relapse is key to the success of immunotherapeutic interventions, as they are more efficient when leukemia burden is low. However, optimal schedule and monitoring methods are not well defined. We report the intensive bone marrow monitoring of minimal residual disease (MRD) using flow cytometry (FC) and nested reverse transcription polymerase chain reaction (RT-PCR) whenever a fusion transcript allowed it and chimerism by PCR at 11 timepoints in the first 2 years after transplant. Seventy-one transplants were performed in 59 consecutive children, for acute myeloid (n = 38), lymphoid (n = 31), or mixed-phenotype (n = 2) leukemia. MRD was monitored in 62 cases using FC (n = 58) and/or RT-PCR (n = 35). Sixty-seven percent of leukemia recurrences were detected before overt relapse, with a detection rate of 89% by RT-PCR and 40% by FC alone. Increased mixed chimerism was never the first evidence of recurrence. Two patients monitored by RT-PCR relapsed without previous MRD detection, one after missed scheduled evaluation and the other 4.7 years post transplant. Among the 22 cases with MRD detection without overt relapse, 19 received therapeutic interventions. Eight (42%) never relapsed. In conclusion, intensive marrow monitoring by RT-PCR effectively allows for early detection of posttransplant leukemia recurrence.

Unifying heterogeneous expression data to predict targets for CAR-T cell therapy

Chimeric antigen receptor (CAR) T-cell therapy combines antigen-specific properties of monoclonal antibodies with the lytic capacity of T cells. An effective and safe CAR-T cell therapy strategy relies on identifying an antigen that has high expression and is tumor specific. This strategy has been successfully used to treat patients with CD19+ B-cell acute lymphoblastic leukemia (B-ALL). Finding a suitable target antigen for other cancers such as acute myeloid leukemia (AML) has proven challenging, as the majority of currently targeted AML antigens are also expressed on hematopoietic progenitor cells (HPCs) or mature myeloid cells. Herein, we developed a computational method to perform a data transformation to enable the comparison of publicly available gene expression data across different datasets or assay platforms. The resulting transformed expression values (TEVs) were used in our antigen prediction algorithm to assess suitable tumor-associated antigens (TAAs) that could be targeted with CAR-T cells. We validated this method by identifying B-ALL antigens with known clinical effectiveness, such as CD19 and CD22. Our algorithm predicted TAAs being currently explored preclinically and in clinical CAR-T AML therapy trials, as well as novel TAAs in pediatric megakaryoblastic AML. Thus, this analytical approach presents a promising new strategy to mine diverse datasets for identifying TAAs suitable for immunotherapy.

Dual Targeting CAR-T Cells with Optimal Costimulation and Metabolic Fitness enhance Antitumor Activity and Prevent Escape in Solid Tumors

Chimeric antigen receptor (CAR) T cells showed great activity in hematologic malignancies. However, heterogeneous antigen expression in tumor cells and suboptimal CAR-T cell persistence remain critical aspects to achieve clinical responses in patients with solid tumors. Here we show that CAR-T cells targeting simultaneously two tumor-associated antigens and providing transacting CD28 and 4-1BB costimulation, while sharing the sane CD3ζ-chain cause rapid antitumor effects in in vivo stress conditions, protection from tumor re-challenge and prevention of tumor escape due to low antigen density. Molecular and signaling studies indicate that T cells engineered with the proposed CAR design demonstrate sustained phosphorylation of T cell receptor-associated (TCR) signaling molecules and a molecular signature supporting CAR-T cell proliferation and long-term survival. Furthermore, metabolic profiling of CAR-T cells displayed induction of glycolysis that sustains rapid effector T cell function, but also preservation of oxidative functions, which are critical for T cell long-term persistence.

Clinical determinants of relapse following CAR-T therapy for hematologic malignancies: Coupling active strategies to overcome therapeutic limitations

The advent of chimeric antigen receptor (CAR)-T cell therapy has been hailed as a major breakthrough in the treatment of B cell acute lymphoblastic leukemia (B-ALL) and diffuse large B-cell lymphoma (DLBCL). While multiple promising CAR-T cell clinical trials continue to receive approval from the FDA and the Chinese Clinical Trial Register (ChiCTR), many hematologic malignancies patients nonetheless experience disease relapse following treatment as a consequence of genetic mutations, antigen escape, lineage switching, poor CAR-T cell persistence, CAR T cell exhaustion, and immunogenicity against CAR T cells. In this article, we summarize the structural characteristics of CAR constructs and discuss clinical factors known to be related to relapse following CAR-T cell treatment. By better understanding the mechanistic basis for such disease recurrence, it will be possible to fully realize the potential of this potent therapeutic modality in the future. This review will focus on current activate strategies aimed at overcoming known limitations to CAR-T cell therapy in an effort to improve hematologic malignancies patient outcomes.

LILRB1: A Novel Diagnostic B-Cell Marker to Distinguish Neoplastic B Lymphoblasts From Hematogones

OBJECTIVES

New B-cell markers are needed for monitoring B lymphoblastic leukemia (B-ALL) in the era of immunotherapies directed against CD19 and CD22. The expression of leukocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1) on hematogones in bone marrow (BM) and neoplastic B lymphoblasts has not yet been systematically investigated.

METHODS

We assessed LILRB1 expression pattern on B cells in 19 control BMs and 22 B-ALL cases by flow cytometry.

RESULTS

In all cases, mature B cells and hematogones exhibited a consistent pattern of LILRB1 expression with variable intensity over different stages of maturation, including a characteristic V-shaped pattern on hematogones. While neoplastic B lymphoblasts in all cases expressed LILRB1, the pattern of expression was distinctly abnormal relative to hematogones (loss of the dynamic pattern in all cases and abnormal expression levels in 83% of cases).

CONCLUSIONS

LILRB1 is a novel diagnostic B-cell marker to aid in distinguishing neoplastic B lymphoblasts from hematogones.

HOIP limits anti-tumor immunity by protecting against combined TNF and IFN-gamma-induced apoptosis

The success of cancer immunotherapy is limited to a subset of patients, highlighting the need to identify the processes by which tumors evade immunity. Using CRISPR/Cas9 screening, we reveal that melanoma cells lacking HOIP, the catalytic subunit of LUBAC, are highly susceptible to both NK and CD8⁺ T-cell-mediated killing. We demonstrate that HOIP-deficient tumor cells exhibit increased sensitivity to the combined effect of the inflammatory cytokines, TNF and IFN-γ, released by NK and CD8⁺ T cells upon target recognition. Both genetic deletion and pharmacological inhibition of HOIP augment tumor cell sensitivity to combined TNF and IFN-γ. Together, we unveil a protective regulatory axis, involving HOIP, which limits a transcription-dependent form of cell death that engages both intrinsic and extrinsic apoptotic machinery upon exposure to TNF and IFN-γ. Our findings highlight HOIP inhibition as a potential strategy to harness and enhance the killing capacity of TNF and IFN-γ during immunotherapy.

Inhibiting Lysine Demethylase 1A Improves L1CAM-Specific CAR T Cell Therapy by Unleashing Antigen-Independent Killing via the FAS-FASL Axis

Simple Summary

Solid tumor cells can lose or heterogeneously express antigens to become resistant to chimeric antigen receptor (CAR) T cell therapy. Here, we explore whether epigenetic manipulation to unleash antigen-independent killing mechanisms can overcome this hurdle. KDM1A is overexpressed in many cancers and removes lysine methylation on histones that keeps the DNA firmly packed to selectively activate or repress gene activity, depending on the specific lysine target. KDM1A also regulates the expression of nonhistone proteins. We inhibited KDM1A in the childhood tumor, neuroblastoma, to increase FAS expression on tumor cells. The FAS receptor can be triggered to induce cell death when bound by the FAS ligand on CAR and other activated T cells present in the tumor environment, even if the tumor cells lack the target antigen. FAS upregulation via KDM1A inhibition sensitized neuroblastoma cells to FAS-FASL-mediated killing and augmented CAR T cell therapy against antigen-poor or even antigen-negative neuroblastoma.

Abstract

Chimeric antigen receptor (CAR) T cell therapy has emerged as a promising treatment strategy, however, therapeutic success against solid tumors such as neuroblastoma remains modest. Recurrence of antigen-poor tumor variants often ultimately results in treatment failure. Using antigen-independent killing mechanisms such as the FAS receptor (FAS)-FAS ligand (FASL) axis through epigenetic manipulation may be a way to counteract the escape achieved by antigen downregulation. Analysis of public RNA-sequencing data from primary neuroblastomas revealed that a particular epigenetic modifier, the histone lysine demethylase 1A (KDM1A), correlated negatively with FAS expression. KDM1A is known to interact with TP53 to repress TP53-mediated transcriptional activation of genes, including FAS. We showed that pharmacologically blocking KDM1A activity in neuroblastoma cells with the small molecule inhibitor, SP-2509, increased FAS cell-surface expression in a strictly TP53-dependent manner. FAS upregulation sensitized neuroblastoma cells to FAS-FASL-dependent killing and augmented L1CAM-directed CAR T cell therapy against antigen-poor or even antigen-negative tumor cells in vitro. The improved therapeutic response was abrogated when the FAS-FASL interaction was abolished with an antagonistic FAS antibody. Our results show that KDM1A inhibition unleashes an antigen-independent killing mechanism via the FAS-FASL axis to make tumor cell variants that partially or totally suppress antigen expression susceptible to CAR T cell therapy.

Cytoplasmic CD79a is a promising biomarker for B lymphoblastic leukemia follow up post CD19 CAR-T therapy

Minimal residual disease (MRD) detection is an important prognostic parameter in patients with refractory or relapsed B-cell acute lymphoblastic leukemia (R/R B-ALL). CD79a has been reported to exhibit a high degree of linage-specificity for B-cell differentiation, with a specificity of 88% and a sensitivity of 100%. In this study, we investigated the efficiency and prognostic role of cytoplasmic CD79a (cCD79a) antibody-gated multicolor flow cytometry (MFC) in MRD detection in patients with B-ALL who received CD19-targeted chimeric antigen receptor (CAR) T-cell therapy bridging to allogeneic hematopoietic stem cell transplantation (allo-HSCT). The retrospective analysis was carried on to 59 patients who accepted allo-HSCT after CD19-CAR-T infusion from June 2016 to May 2017. The MFC MRD statuses before and after allo-HSCT were both strongly correlated with the transplantation prognosis, the MFC panel with cCD79a gating can effectively monitor MRD after CD19 CAR T-cell therapy and predict the prognosis after allo-HSCT. Trial registration: ClinicalTrials#: ChiCTR-IIh-16008711.gov: NCT03173417. Registered 30 May 2017 - retrospectively registered, https://www.clinicaltrials.gov/.

PSMA-Specific CAR-Engineered T Cells for Prostate Cancer: CD28 Outperforms Combined CD28-4-1BB "Super-Stimulation"

Prostate cancer (PCa) is the second leading cause of malignancy-related mortality in males in the Western world. Although treatment like prostatectomy and radiotherapy for localized cancer have good results, similar positive outcomes are not achieved in metastatic PCa. Consequently, these aggressive and metastatic forms of PCa urgently need new methods of treatment. We already described an efficient and specific second-generation (2G) Chimeric Antigen Receptor (CAR) against Prostate Specific Membrane Antigen (PSMA), a glycoprotein overexpressed in prostate cancer and also present on neovasculature of several tumor entities. In an attempt to improve efficacy and in vivo survival of anti-PSMA 2G CAR-T cells, we developed a third generation (3G) CAR containing two costimulatory elements, namely CD28 and 4-1BB co-signaling domains, in addition to CD3ζ. Differently from what described for other 3G receptors, our third generation CAR disclosed an antitumor activity in vitro similar to the related 2G CAR that comprises the CD28 co-signaling domain only. Moreover, the additional costimulatory domain produced detrimental effects, which could be attributed to an increased activation-induced cell death (AICD). Indeed, such "superstimulation" resulted in an exhausted phenotype of CAR-T cells, after prolonged in vitro restimulation, a higher frequency of cell death, and an impairment in yielding sufficient numbers of transgenic T lymphocytes. Thus, the optimal combination of costimulatory domains for CAR development should be assessed cautiously and evaluated case-by-case.

Disease category-specific annotation of variants using an ensemble learning framework

Understanding the impact of non-coding sequence variants on complex diseases is an essential problem. We present a novel ensemble learning framework-CASAVA, to predict genomic loci in terms of disease category-specific risk. Using disease-associated variants identified by GWAS as training data, and diverse sequencing-based genomics and epigenomics profiles as features, CASAVA provides risk prediction of 24 major categories of diseases throughout the human genome. Our studies showed that CASAVA scores at a genomic locus provide a reasonable prediction of the disease-specific and disease category-specific risk prediction for non-coding variants located within the locus. Taking MHC2TA and immune system diseases as an example, we demonstrate the potential of CASAVA in revealing variant-disease associations. A website (http://zhanglabtools.org/CASAVA) has been built to facilitate easily access to CASAVA scores.

Cytokine release syndrome after haploidentical hematopoietic stem cell transplantation with antithymocyte globulin: risk factors analysis and poor impact on outcomes for non-remisssion patients

INTRODUCTION

Cytokine release syndrome (CRS) is a common complication after T-replete HLA haploidentical hematopoietic cell transplantation (haplo-HCT) with PTCy. We aim to assess the incidence, severity, and impact of CRS on clinical outcomes of patients who received haplo-HCT using Beijing Protocol.

METHODS

This was a single-enter retrospective analysis of 286 subjects who received haplo-HCT with Antithymocyte Globulin (ATG).

RESULTS

We identified 147/268 (54.9%) patients who developed CRS, grade 1 CRS (32.5%) and grade ≥2 CRS (22.4%). Eight patients developed severe CRS. The incidence and severity of CRS did not show significant discrimination among patients who received different doses of ATG. By multivariable analysis, age and the disease status at transplantation were significantly associated with the occurrence of CRS (p =.000 and p = .021). In the univariate analysis for the severity of CRS, compared with CRS grade ≥2, patients with CRS grade 0-1 had higher 1-year overall survival (OS) (p = .009). The cumulative incidence of 100-day grades II-IV acute GVHD was 12.4%. The incidence did not show significant differences between patients with CRS or not. The devolvement of CRS is associated with worse OS, inferior disease-free survival, and higher nonrelapse mortality significantly. But the result appeared to be limited to patients in uncomplete remission status before transplantation.

DISCUSSION AND CONCLUSIONS

CRS is less frequent and milder with a protocol based on ATG. CRS can potentially affect the outcomes after haplo-HCT especially for patients in an uncomplete remission. Prospective clinical trials are needed to provide an appropriate scheme for CRS prophylaxis.

Advances in Liver Transplantation: where are we in the pursuit of transplantation tolerance?

Liver transplantation is the ultimate treatment option for end-stage liver disease. Breakthroughs in surgical practice and immunosuppression have seen considerable advancements in survival after transplantation. However, the intricate management of immunosuppressive regimens, balancing desired immunological quiescence while minimizing toxicity has proven challenging. Diminishing improvements in long-term morbidity and mortality have been inextricably linked with the protracted use of these medications. As such, there is now enormous interest to devise protocols that will allow us to minimize or completely withdraw immunosuppressants after transplantation. Immunosuppression withdrawal trials have proved the reality of tolerance following liver transplantation, however, without intervention will only occur after several years at the risk of potential cumulative immunosuppression-related morbidity. Focus has now been directed at accelerating this phenomenon through tolerance-inducing strategies. In this regard, efforts have seen the use of regulatory cell immunotherapy. Here we focus particularly on regulatory T cells, discussing preclinical data that propagated several clinical trials of adoptive cell therapy in liver transplantation. Furthermore, we describe efforts to further optimize the specificity and survival of regulatory cell therapy guided by concurrent immunomonitoring studies and the development of novel technologies including chimeric antigen receptors and co-administration of low-dose IL-2.

Pediatric Mixed-Phenotype Acute Leukemia: What's New?

Simple Summary

Pediatric mixed-phenotype leukemia is a rare form of blood cancer in children. In this review, we cover both the evolution of treatment over the past several years and outline new emerging concepts in this disease.

Abstract

Mixed-phenotype acute leukemias (MPAL) are rare in children and often lack consensus on optimal management. This review examines the current controversies and emerging paradigms in the management of pediatric MPAL. We examine risk stratification, outcomes of recent retrospective and prospective collaborative trials, and the role of transplantation and precision genomics, and outline emerging targets and concepts in this rare entity.

Bispecific Antibodies in Multiple Myeloma: Present and Future

Despite many recent advances in therapy, there is still no plateau in overall survival curves in multiple myeloma. Bispecific antibodies are a novel immunotherapeutic approach designed to bind antigens on malignant plasma cells and cytotoxic immune effector cells. Early-phase clinical trials targeting B-cell maturation antigen (BCMA), GPRC5D, and FcRH5 have demonstrated a favorable safety profile, with mainly low-grade cytokine release syndrome, cytopenias, and infections. Although dose escalation is ongoing in several studies, early efficacy data show response rates in the most active dose cohorts between 61% and 83% with many deep responses; however, durability remains to be established. Further clinical trial data are eagerly anticipated.

SIGNIFICANCE

Overall survival of triple-class refractory multiple myeloma remains poor. Bispecific antibodies are a novel immunotherapeutic modality with a favorable safety profile and impressive preliminary efficacy in heavily treated patients. Although more data are needed, bispecifics will likely become an integral part of the multiple myeloma treatment paradigm in the near future. Studies in earlier lines of therapy and in combination with other active anti-multiple myeloma agents will help further define the role of bispecifics in multiple myeloma.

Current status and perspective of CAR-T and CAR-NK cell therapy trials in Germany

Chimeric antigen receptor (CAR)-T cell therapies are on the verge of becoming powerful immunotherapeutic tools for combating hematological diseases confronted with pressing medical needs. Lately, CAR-NK cell therapies have also come into focus as novel therapeutic options to address hurdles related to CAR-T cell therapies, such as therapy-induced side effects. Currently, more than 500 CAR-T and 17 CAR-NK cell trials are being conducted worldwide including the four CAR-T cell products Kymriah, Yescarta, Tecartus and Breyanzi, which are already available on the market. Most CAR-T cell-based gene therapy products that are under clinical evaluation consist of autologous enriched T cells, whereas CAR-NK cell-based approaches can be generated from allogeneic donors. Besides modification based on a second-generation CAR, more advanced CAR-immune cell therapeutics are being tested, which utilize precise insertion of genes to circumvent graft-versus-host disease (GvHD) or employ a dual targeting approach and adapter CARs in order to avoid therapy resistance caused by antigen loss. In this review, we are going to take a closer look at the commercial CAR-T cell therapies, as well as on CAR-T and CAR-NK cell products, which are currently under evaluation in clinical trials, that are being conducted in Germany.

Gene-circuit therapy on the horizon: synthetic biology tools for engineered therapeutics

Therapeutic genome modification requires precise control over the introduced therapeutic functions. Current approaches of gene and cell therapy fail to deliver such command and rely on semi-quantitative methods with limited influence on timing, contextuality and levels of transgene expression, and hence on therapeutic function. Synthetic biology offers new opportunities for quantitative functionality in designing therapeutic systems and their components. Here, we discuss synthetic biology tools in their therapeutic context, with examples of proof-of-principle and clinical applications of engineered synthetic biomolecules and higher-order functional systems, i.e. gene circuits. We also present the prospects of future development towards advanced gene-circuit therapy.

Chimeric antigen receptor T-cell therapy: An emergency medicine focused review

INTRODUCTION

Several novel cancer therapies have been recently introduced, each with complications that differ from chemotherapy and radiation.

OBJECTIVE

This narrative review discusses complications associated with chimeric antigen receptor (CAR) T-cell therapy for emergency clinicians.

DISCUSSION

Novel immune-based cancer therapies including CAR T-cell therapy have improved the care of patients with malignancy, primarily lymphoma and leukemia. However, severe complications may arise, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). CRS is associated with excessive cytokine release that results in severe end organ injury. Patients present with fever and a range of symptoms based on the affected organs. Grading is determined by the need for cardiopulmonary intervention, while management focuses on resuscitation, evaluation for other concomitant conditions, and treatment with tocilizumab or steroids. ICANS is also associated with cytokine release, causing patients to present with a variety of neurologic features. A grading system is available for ICANS based on feature severity. Management is supportive with steroids. Other complications of CAR T-cell therapy include infusion reactions, hypogammaglobulinemia, tumor lysis syndrome, cytopenias, cardiac toxicity, and graft-versus-host disease.

CONCLUSIONS

Knowledge of this novel cancer therapy class and the potential complications can improve the care of these patients in the emergency department setting.

Highly Efficient Transfection of Human Primary T Lymphocytes Using Droplet-Enabled Mechanoporation

Whole-cell-based therapy has been extensively used as an effective disease treatment approach, and it has rapidly changed the therapeutic paradigm. To fully accommodate this shift, advances in genome modification and cell reprogramming methodologies are critical. Traditionally, molecular tools such as viral and polymer nanocarriers and electroporation have been the norm for internalizing external biomolecules into cells for cellular engineering. However, these approaches are not fully satisfactory considering their cytotoxicity, high cost, low scalability, and/or inconsistent and ineffective delivery and transfection. To address these challenges, we present an approach that leverages droplet microfluidics with cell mechanoporation, bringing intracellular delivery to the next level. In our approach, cells and external cargos such as mRNAs and plasmid DNAs are coencapsulated into droplets, and as they pass through a series of narrow constrictions, the cell membrane is mechanically permeabilized where the cargos in the vicinity are internalized via convective solution exchange enhanced by recirculation flows developed in the droplets. Using this principle, we demonstrated a high level of functional macromolecule delivery into various immune cells, including human primary T cells. By utilizing droplets, the cargo consumption was drastically reduced, and near-zero clogging was realized. Furthermore, high scalability without sacrificing cell viability and superior delivery over state-of-the-art methods and benchtop techniques were demonstrated. Notably, the droplet-based intracellular delivery strategy presented here can be further applied to other mechanoporation microfluidic techniques, highlighting its potential for cellular engineering and cell-based therapies.

Engineered Cytokines for Cancer and Autoimmune Disease Immunotherapy

Cytokine signaling is critical to a range of biological processes including cell development, tissue repair, aging, and immunity. In addition to acting as key signal mediators of the immune system, cytokines can also serve as potent immunotherapies with more than 20 recombinant products currently Food and Drug Administration (FDA)-approved to treat conditions including hepatitis, multiple sclerosis, arthritis, and various cancers. Yet despite their biological importance and clinical utility, cytokine immunotherapies suffer from intrinsic challenges that limit their therapeutic potential including poor circulation, systemic toxicity, and low tissue- or cell-specificity. In the past decade in particular, methods have been devised to engineer cytokines in order to overcome such challenges and here, the myriad strategies are reviewed that may be employed in order to improve the therapeutic potential of cytokine and chemokine immunotherapies with applications in cancer and autoimmune disease therapy, as well as tissue engineering and regenerative medicine. For clarity, these strategies are collected and presented as they vary across size scales, ranging from single amino acid substitutions, to larger protein-polymer conjugates, nano/micrometer-scale particles, and macroscale implants. Together, this work aims to provide readers with a timely view of the field of cytokine engineering with an emphasis on early-stage therapeutic approaches.

Microfluidic and Nanofluidic Intracellular Delivery

Innate cell function can be artificially engineered and reprogrammed by introducing biomolecules, such as DNAs, RNAs, plasmid DNAs, proteins, or nanomaterials, into the cytosol or nucleus. This process of delivering exogenous cargos into living cells is referred to as intracellular delivery. For instance, clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 gene editing begins with internalizing Cas9 protein and guide RNA into cells, and chimeric antigen receptor-T (CAR-T) cells are prepared by delivering CAR genes into T lymphocytes for cancer immunotherapies. To deliver external biomolecules into cells, tools, including viral vectors, and electroporation have been traditionally used; however, they are suboptimal for achieving high levels of intracellular delivery while preserving cell viability, phenotype, and function. Notably, as emerging solutions, microfluidic and nanofluidic approaches have shown remarkable potential for addressing this open challenge. This review provides an overview of recent advances in microfluidic and nanofluidic intracellular delivery strategies and discusses new opportunities and challenges for clinical applications. Furthermore, key considerations for future efforts to develop microfluidics- and nanofluidics-enabled next-generation intracellular delivery platforms are outlined.

IDO Inhibition Facilitates Antitumor Immunity of Vγ9Vδ2 T Cells in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) escape from immune-mediated destruction was associated with immunosuppressive responses that dampened the activation of tumor-infiltrating CD8 and γδ T cells. TNBC had a higher level of programmed cell death 1-ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase (IDO), compared with other breast cancer subtypes. But, clinical studies have revealed that the response rate of PD-1/PD-L1 antibody for TNBC treatment was relatively low. However, the antitumor responses of human Vγ9Vδ2 T cells or IDO inhibitor in TNBC treatment are unknown. In this study, we found that IDO1 and PD-L1 were highly expressed in TNBC patients. Analysis of the clinical samples demonstrated that Vγ9Vδ2 T cells became exhausted in triple-negative breast cancer patients. And Vγ9Vδ2 T cells combined with αPD-L1 could not further enhance their antitumor responses in vitro and in vivo. However, Vγ9Vδ2 T cells combined with IDO1 inhibitor 1-Methyl-L-tryptophan (1-MT) or Lindrostat showed substantial inhibitory effects on MDA-MB-231 tumor cells. Finally, we found that IDO1 inhibitor promoted T cell’s cytotoxicity by enhancing perforin production. These results converged to suggest the potential application of Vγ9Vδ2 T cells treated with IDO1 inhibitor for TNBC therapy.

Innovative therapeutic strategy for B-cell malignancies that combines obinutuzumab and cytokine-induced killer cells

Background

Patients affected by aggressive B-cell malignancies who are resistant to primary or salvage chemoimmunotherapy have an extremely poor prognosis and limited therapeutic options. Promising therapeutic success has been achieved with the infusion of CD19 chimeric antigen receptor-T cells, but several limits still restrain the administration to a limited proportion of patients. This unmet clinical need might be fulfilled by an adoptive immunotherapy approach that combines cytokine-induced killer (CIK) cells and monoclonal antibodies (mAb) to the CD20 antigen. Indeed, CIK cells are an effector population endowed with antitumor activity, which can be further improved and antigen-specifically redirected by clinical-grade mAb triggering antibody-dependent cell-mediated cytotoxicity.

Methods

CIK cells were generated from peripheral blood of patients affected by different B-cell malignancies using a blinatumomab-based cell culture protocol. Effector cells were combined with the anti-CD20 mAb obinutuzumab and their therapeutic activity was assessed both in vitro and in vivo.

Results

CIK cells were successfully expanded in clinically relevant numbers, starting from small volumes of peripheral blood with extremely low CD3⁺ counts and high tumor burden. This relied on the addition of blinatumumab in culture, which leads to the simultaneous expansion of effector cells and the complete elimination of the neoplastic component. Moreover, CIK cells were highly cytotoxic in vitro against both B-cell tumor cell lines and autologous neoplastic targets, and had a significant therapeutic efficacy against a B-cell malignancy patient-derived xenograft on in vivo transfer.

Conclusions

The combination of an easily expandable CIK cell effector population with a mAb already in clinical use establishes a tumor antigen-specific redirection strategy that can be rapidly translated into clinical practice, providing an effective therapeutic alternative for B-cell malignancies without any need for genetic modifications. Additionally, the approach can be potentially applied to an extremely vast array of different tumors by simply substituting the targeting mAb.

Effective combination immunotherapy using oncolytic viruses to deliver CAR targets to solid tumors

Chimeric antigen receptor (CAR)-engineered T cell therapy for solid tumors is limited by the lack of both tumor-restricted and homogeneously expressed tumor antigens. Therefore, we engineered an oncolytic virus to express a nonsignaling, truncated CD19 (CD19t) protein for tumor-selective delivery, enabling targeting by CD19-CAR T cells. Infecting tumor cells with an oncolytic vaccinia virus coding for CD19t (OV19t) produced de novo CD19 at the cell surface before virus-mediated tumor lysis. Cocultured CD19-CAR T cells secreted cytokines and exhibited potent cytolytic activity against infected tumors. Using several mouse tumor models, delivery of OV19t promoted tumor control after CD19-CAR T cell administration. OV19t induced local immunity characterized by tumor infiltration of endogenous and adoptively transferred T cells. CAR T cell-mediated tumor killing also induced release of virus from dying tumor cells, which propagated tumor expression of CD19t. Our study features a combination immunotherapy approach using oncolytic viruses to promote de novo CAR T cell targeting of solid tumors.

Interferon-γ: teammate or opponent in the tumour microenvironment?

Cancer immunotherapy offers substantive benefit to patients with various tumour types, in some cases leading to complete tumour clearance. However, many patients do not respond to immunotherapy, galvanizing the field to define the mechanisms of pre-existing and acquired resistance. Interferon-γ (IFNγ) is a cytokine that has both protumour and antitumour activities, suggesting that it may serve as a nexus for responsiveness to immunotherapy. Many cancer immunotherapies and chemotherapies induce IFNγ production by various cell types, including activated T cells and natural killer cells. Patients resistant to these therapies commonly have molecular aberrations in the IFNγ signalling pathway or express resistance molecules driven by IFNγ. Given that all nucleated cells can respond to IFNγ, the functional consequences of IFNγ production need to be carefully dissected on a cell-by-cell basis. Here, we review the cells that produce IFNγ and the different effects of IFNγ in the tumour microenvironment, highlighting the pleiotropic nature of this multifunctional and abundant cytokine.

CARTmath-A Mathematical Model of CAR-T Immunotherapy in Preclinical Studies of Hematological Cancers

Immunotherapy has gained great momentum with chimeric antigen receptor T cell (CAR-T) therapy, in which patient's T lymphocytes are genetically manipulated to recognize tumor-specific antigens, increasing tumor elimination efficiency. In recent years, CAR-T cell immunotherapy for hematological malignancies achieved a great response rate in patients and is a very promising therapy for several other malignancies. Each new CAR design requires a preclinical proof-of-concept experiment using immunodeficient mouse models. The absence of a functional immune system in these mice makes them simple and suitable for use as mathematical models. In this work, we develop a three-population mathematical model to describe tumor response to CAR-T cell immunotherapy in immunodeficient mouse models, encompassing interactions between a non-solid tumor and CAR-T cells (effector and long-term memory). We account for several phenomena, such as tumor-induced immunosuppression, memory pool formation, and conversion of memory into effector CAR-T cells in the presence of new tumor cells. Individual donor and tumor specificities are considered uncertainties in the model parameters. Our model is able to reproduce several CAR-T cell immunotherapy scenarios, with different CAR receptors and tumor targets reported in the literature. We found that therapy effectiveness mostly depends on specific parameters such as the differentiation of effector to memory CAR-T cells, CAR-T cytotoxic capacity, tumor growth rate, and tumor-induced immunosuppression. In summary, our model can contribute to reducing and optimizing the number of in vivo experiments with in silico tests to select specific scenarios that could be tested in experimental research. Such an in silico laboratory is an easy-to-run open-source simulator, built on a Shiny R-based platform called CARTmath. It contains the results of this manuscript as examples and documentation. The developed model together with the CARTmath platform have potential use in assessing different CAR-T cell immunotherapy protocols and its associated efficacy, becoming an accessory for in silico trials.

Beyond the storm - subacute toxicities and late effects in children receiving CAR T cells

As clinical advances with chimeric antigen receptor (CAR) T cells are increasingly described and the potential for extending their therapeutic benefit grows, optimizing the implementation of this therapeutic modality is imperative. The recognition and management of cytokine release syndrome (CRS) marked a milestone in this field; however, beyond the understanding gained in treating CRS, a host of additional toxicities and/or potential late effects of CAR T cell therapy warrant further investigation. A multicentre initiative involving experts in paediatric cell therapy, supportive care and/or study of late effects from cancer and haematopoietic stem cell transplantation was convened to facilitate the comprehensive study of extended CAR T cell-mediated toxicities and establish a framework for new systematic investigations of CAR T cell-related adverse events. Together, this group identified six key focus areas: extended monitoring of neurotoxicity and neurocognitive function, psychosocial considerations, infection and immune reconstitution, other end organ toxicities, evaluation of subsequent neoplasms, and strategies to optimize remission durability. Herein, we present the current understanding, gaps in knowledge and future directions of research addressing these CAR T cell-related outcomes. This systematic framework to study extended toxicities and optimization strategies will facilitate the translation of acquired experience and knowledge for optimal application of CAR T cell therapies.

Cardiovascular Toxicities of CAR T-cell Therapy

PURPOSE OF REVIEW

This review provides a contemporary overview of current studies outlining the incidence and characteristics of CAR T-cell cardiotoxicity in an effort to identify future directions for research and potential opportunities for prevention and intervention.

RECENT FINDINGS

Cardiovascular events occurred in anywhere between 10 and 36% of patients in CAR T-cell clinical trials, ranging from tachycardia, hypotension, arrhythmia, decreased left ventricular systolic function to cardiogenic shock and death. Cardiac events are more often associated higher grades (> 2) of cytokine release syndrome and frequently proceeded by an elevated troponin. There is a growing recognition of cardiotoxicities of CAR T-cell therapy but has a limited study in this area. The mechanism of left ventricular dysfunction due to CAR T-cell therapy is also unknown. As CAR T-cell use expands, it becomes imperative to truly understand the mechanism behind cardiac injury and to assess long-term follow-up data as this will allow for surveillance, early intervention, and potentially prevention of cardiotoxicity.

Advances in the Diagnosis and Treatment of Pediatric Acute Lymphoblastic Leukemia

The outcomes of pediatric acute lymphoblastic leukemia (ALL) have improved remarkably during the last five decades. Such improvements were made possible by the incorporation of new diagnostic technologies, the effective administration of conventional chemotherapeutic agents, and the provision of better supportive care. With the 5-year survival rates now exceeding 90% in high-income countries, the goal for the next decade is to improve survival further toward 100% and to minimize treatment-related adverse effects. Based on genome-wide analyses, especially RNA-sequencing analyses, ALL can be classified into more than 20 B-lineage subtypes and more than 10 T-lineage subtypes with prognostic and therapeutic implications. Response to treatment is another critical prognostic factor, and detailed analysis of minimal residual disease can detect levels as low as one ALL cell among 1 million total cells. Such detailed analysis can facilitate the rational use of molecular targeted therapy and immunotherapy, which have emerged as new treatment strategies that can replace or reduce the use of conventional chemotherapy.

Bispecific Antibodies: A Review of Development, Clinical Efficacy and Toxicity in B-Cell Lymphomas

The treatment landscape of B-cell lymphomas is evolving with the advent of novel agents including immune and cellular therapies. Bispecific antibodies (bsAbs) are molecules that recognise two different antigens and are used to engage effector cells, such as T-cells, to kill malignant B-cells. Several bispecific antibodies have entered early phase clinical development since the approval of the CD19/CD3 bispecific antibody, blinatumomab, for relapsed/refractory acute lymphoblastic leukaemia. Novel bsAbs include CD20/CD3 antibodies that are being investigated in both aggressive and indolent non-Hodgkin lymphoma with encouraging overall response rates including complete remissions. These results are seen even in heavily pre-treated patient populations such as those who have relapsed after chimeric antigen receptor T-cell therapy. Potential toxicities include cytokine release syndrome, neurotoxicity and tumour flare, with a number of strategies existing to mitigate these risks. Here, we review the development of bsAbs, their mechanism of action and the different types of bsAbs and how they differ in structure. We will present the currently available data from clinical trials regarding response rates, progression free survival and outcomes across a range of non-Hodgkin lymphoma subtypes. Finally, we will discuss the key toxicities of bsAbs, their rates and management of these adverse events.

Emerging immunotherapies for malignant glioma: from immunogenomics to cell therapy

As immunotherapy assumes a central role in the management of many cancers, ongoing work is directed at understanding whether immune-based treatments will be successful in patients with glioblastoma (GBM). Despite several large studies conducted in the last several years, there remain no FDA-approved immunotherapies in this patient population. Nevertheless, there are a range of exciting new approaches being applied to GBM, all of which may not only allow us to develop new treatments but also help us understand fundamental features of the immune response in the central nervous system. In this review, we summarize new developments in the application of immune checkpoint blockade, from biomarker-driven patient selection to the timing of treatment. Moreover, we summarize novel work in personalized immune-oncology by reviewing work in cancer immunogenomics-driven neoantigen vaccine studies. Finally, we discuss cell therapy efforts by reviewing the current state of chimeric antigen receptor T-cell therapy.

CD19 CAR-T cell treatment conferred sustained remission in B-ALL patients with minimal residual disease

The persistence or recurrence of minimal residual disease (MRD) after chemotherapy predicts relapse of B-cell acute lymphoblastic leukemia (B-ALL). CD19-directed chimeric antigen receptor T (CD19 CAR-T) cells have shown promising responses in B-ALL. However, their role in chemotherapy-refractory MRD-positive B-ALL remains unclear. Here we aimed to assess the effectiveness and safety of CD19 CAR-T cells in MRD-positive B-ALL patients. From January 2018, a total of 14 MRD-positive B-ALL patients received one or more infusions of autogenous CD19 CAR-T cells. Among them, 12 patients achieved MRD-negative remission after one cycle of CAR-T infusion. At a median follow-up time of 647 days (range 172–945 days), the 2-year event-free survival rate in MRD-positive patients was 61.2% ± 14.0% and the 2-year overall survival was 78.6 ± 11.0%, which were significantly higher than patients with active disease (blasts ≥ 5% or with extramedullary disease). Moreover, patients with MRD had a lower grade of cytokine release syndrome (CRS) than patients with active disease. However, the peak expansion of CAR-T cells in MRD positive patients showed no statistical difference compared to patients with active disease. Five patients received two or more CAR-T cell infusions and these patients showed a decreased peak expansion of CAR-T cell in subsequent infusions. In conclusion, pre-emptive CD19 CAR-T cell treatment is an effective and safe approach and may confer sustained remission in B-ALL patients with chemotherapy-refractory MRD. The trials were registered at www.chictr.org.cn as ChiCTR-ONN-16009862 (November 14, 2016) and ChiCTR1800015164 (March 11, 2018).

CAR T cells Targeting Human Immunoglobulin Light Chains Eradicate Mature B-cell Malignancies While Sparing a Subset of Normal B Cells

PURPOSE

CD19-redirected chimeric antigen receptor (CAR.CD19) T cells promote clinical responses in patients with relapsed/refractory B-cell non-Hodgkin lymphomas and chronic lymphocytic leukemia (CLL). However, patients showing sustained clinical responses after CAR.CD19-T treatment show increased infection risk due to compromised B-lymphocyte recovery. Mature B cell-derived malignancies express monoclonal immunoglobulins bearing either κ- or λ-light chains. We initially constructed CAR-T targeting the κ-light-chain (CAR.κ) and established a clinical study with it. After optimizing the CAR molecule, cells developed CAR-T targeting the λ-light chain (CAR.λ) and we explored their antitumor activity.

EXPERIMENTAL DESIGN

Using Igλ⁺ lymphoma cell lines and patient-derived Igλ⁺ CLL cells, we evaluated the in vitro tumor cytotoxicity and cytokine profiles of CAR.λ. We also assessed the in vivo efficacy of CAR.λ in xenograft Igλ⁺ lymphoma models including a patient-derived xenograft (PDX) of mantle cell lymphoma, and the effects of λ- or κ-light chain-specific CAR-T on normal B lymphocytes in a humanized murine model.

RESULTS

CAR.λ demonstrated antitumor effects against Igλ⁺ lymphoma cells and patient-derived CLL cells in vitro, and in vivo in xenograft and PDX Igλ⁺ lymphoma murine models. Antitumor activity of CAR.λ was superimposable to CAR.CD19. Furthermore, we demonstrated in the humanized murine model that λ- or κ-light chain-specific CAR-T cells only depleted the corresponding targeted light chain-expressing normal B cells, while sparing the reciprocal light chain carrying B cells.

CONCLUSIONS

Adoptive transfer of CAR.λ and CAR.κ-T cells represents a useful and alternative modality to CAR.CD19-T cells in treating mature B-cell malignancies with minimal impact on humoral immunity.

CAR-T cell therapy: current limitations and potential strategies

Chimeric antigen receptor (CAR)-T cell therapy is a revolutionary new pillar in cancer treatment. Although treatment with CAR-T cells has produced remarkable clinical responses with certain subsets of B cell leukemia or lymphoma, many challenges limit the therapeutic efficacy of CAR-T cells in solid tumors and hematological malignancies. Barriers to effective CAR-T cell therapy include severe life-threatening toxicities, modest anti-tumor activity, antigen escape, restricted trafficking, and limited tumor infiltration. In addition, the host and tumor microenvironment interactions with CAR-T cells critically alter CAR-T cell function. Furthermore, a complex workforce is required to develop and implement these treatments. In order to overcome these significant challenges, innovative strategies and approaches to engineer more powerful CAR-T cells with improved anti-tumor activity and decreased toxicity are necessary. In this review, we discuss recent innovations in CAR-T cell engineering to improve clinical efficacy in both hematological malignancy and solid tumors and strategies to overcome limitations of CAR-T cell therapy in both hematological malignancy and solid tumors.

Beyond conventional immune-checkpoint inhibition - novel immunotherapies for renal cell carcinoma

The management of advanced-stage renal cell carcinoma (RCC) has been transformed by the development of immune-checkpoint inhibitors (ICIs). Nonetheless, most patients do not derive durable clinical benefit from these agents. Importantly, unlike other immunotherapy-responsive solid tumours, most RCCs have only a moderate mutational burden, and paradoxically, high levels of tumour CD8+ T cell infiltration are associated with a worse prognosis in patients with this disease. Building on the successes of antibodies targeting the PD-1 and CTLA4 immune checkpoints, multiple innovative immunotherapies are now in clinical development for the treatment of patients with RCC, including ICIs with novel targets, co-stimulatory pathway agonists, modified cytokines, metabolic pathway modulators, cell therapies and therapeutic vaccines. However, the successful development of such novel immune-based treatments and of immunotherapy-based combinations will require a disease-specific framework that incorporates a deep understanding of RCC immunobiology. In this Review, using the structure provided by the well-described cancer-immunity cycle, we outline the key steps required for a successful antitumour immune response in the context of RCC, and describe the development of promising new immunotherapies within the context of this framework. With this approach, we summarize and analyse the most encouraging targets of novel immune-based therapies within the RCC microenvironment, and review the landscape of emerging antigen-directed therapies for this disease.

Strategies for Dodging the Obstacles in CAR T Cell Therapy

Chimeric antigen receptor (CAR) T cell therapy has offered cancer patients a new alternative therapeutic choice in recent years. This novel type of therapy holds tremendous promise for the treatment of various hematologic malignancies including B-cell acute lymphoblastic leukemia (B-ALL) and lymphoma. However, CAR T cell therapy has experienced its ups and downs in terms of toxicities and efficacy shortcomings. Adverse events such as cytokine release syndrome (CRS), neurotoxicity, graft rejection, on-target off-tumor toxicities, and tumor relapse have tied the rescuing hands of CAR T cell therapies. Moreover, in the case of solid tumor treatment, CAR T cell therapies have not yielded encouraging results mainly due to challenges such as the formidable network of the tumor microenvironments (TME) that operates in a suppressive fashion resulting in CAR T cell dysfunction. In this review, we tend to shine a light on emerging strategies and solutions for addressing the mentioned barriers. These solutions might dramatically help shorten the gap between a successful clinical outcome and the hope for it.

Hematologists' barriers and enablers to screening and recruiting patients to a chimeric antigen receptor (CAR) T cell therapy trial: a theory-informed interview study

BACKGROUND

Novel therapies often fail to reach the bedside due to low trial recruitment rates. Prior to conducting one of the first chimeric antigen receptor (CAR) T cell therapy trials in Canada, we used the Theoretical Domains Framework, a novel tool for identifying barriers and enablers to behavior change, to identify physician-related barriers and enablers to screening and recruiting patients for an early phase immunotherapy trial.

METHODS

We conducted interviews with hematologists across Canada and used a directed content analysis to identify relevant domains reflecting the key factors that may affect screening and recruitment.

RESULTS

In total, we interviewed 15 hematologists. Physicians expressed "cautious hope"; while expressing safety, feasibility, and screening criteria concerns, 14 out of 15 hematologists intended to screen for the trial (domains: knowledge, goals, beliefs about consequences, intentions). Physicians underscored the "challenging contexts," identifying resources, workload, forgetting, and patient wait times to receive CAR T cells as key practical barriers to screening (domains: environmental context and resources, memory, attention and decision-making, behavioral regulation). They also highlighted "variability in roles and procedures" that may lead to missed trial candidates (domain: social and professional role). Left unaddressed, these barriers may undermine trial recruitment.

CONCLUSIONS

This study is among the first to use the Theoretical Domains Framework from the physician perspective to identify recruitment challenges to early phase trials and demonstrates the value of this approach for identifying barriers to screening and recruitment that may not otherwise have been elicited. This approach can optimize trial procedures and may serve to inform future promising early phase cancer therapy trials.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03765177 . Registered on December 5, 2018.

Navigating choice in the face of uncertainty: using a theory informed qualitative approach to identifying potential patient barriers and enablers to participating in an early phase chimeric antigen receptor T (CAR-T) cell therapy trial

OBJECTIVES

Bench to bedside translation of groundbreaking treatments like chimeric antigen receptor T (CAR-T) cell therapy depends on patient participation in early phase trials. Unfortunately, many novel therapies fail to be adequately evaluated due to low recruitment rates, which slows patient access to emerging treatments. Using the Theoretical Domains Framework (TDF), we sought to identify potential patient barriers and enablers to participating in an early phase CAR-T cell therapy trial.

DESIGN

We used qualitative semistructured interviews to identify potential barriers and enablers to patients' hypothetical participation in an early phase CAR-T cell therapy trial. We used the TDF and directed content analysis to identify relevant domains based on frequency, relevance and the presence of conflicting beliefs.

PARTICIPANTS

Canadian adult patients diagnosed with haematological malignancies.

RESULTS

In total, we interviewed 13 participants (8 women, 5 men). Participants ranged in age from 18 to 73 (median=56) and had been living with haematological cancer from a few months to several years. We found participants were unfamiliar with CAR-T cell therapy but wished to know more about treatment safety, efficacy and trial logistics (domains: knowledge, beliefs about consequences). They were motivated by altruistic considerations, though many prioritised personal health benefits despite recognising the goals (ie, establishing safety) of early phase clinical trials (domains: goals, intentions). Every participant valued receiving medical advice from their haematologists and oncologists, though some preferred impartial medical experts to inform their decision making (domain: social influences). Finally, participants indicated that improving access to financial and social supports would improve their trial participation experience (domain: environmental context and resources).

CONCLUSION

Using the TDF allowed us to identify factors that might undermine participation to a CAR-T cell therapy trial and to optimise recruitment processes by considering patient perspectives to taking part in early phase trials.Trial regestration: NCT03765177; Pre-results.

CD19 Chimeric Antigen Receptor-Exosome Targets CD19 Positive B-lineage Acute Lymphocytic Leukemia and Induces Cytotoxicity

CAR-T cell therapy is not without some clinical adverse effects, namely cytokine storms, due to a massive release of cytokines when CAR-T cells multiply in the body. Our goal was to develop exosomes expressing CD19 CAR to treat CD19-positive B-cell malignancies, instead of using whole CD19 CAR-T cells, thereby reducing the clinical risk of uncontrolled cytokine storms. Exosomes are extracellular nanovesicles (30-150 nm), composed of lipids, proteins, and nucleic acids, that carry the fingerprint of their parent cells. Exosomes are a preferred delivery system in nano-immunotherapy. Here, HEK293T parent cells were transduced with CD19 CAR plasmids and cellular CD19 CAR expression was confirmed. Exosomes (Exo-CD19 CAR) were isolated from the conditioned medium of non-transduced (WT) and CD19 CAR plasmid transduced HEK293T cells. Consequently, CD19 B-lineage leukemia cell lines were co-cultured with Exo-CD19 CAR and cell death was measured. Our data show that Exo-CD19 CAR treatment induced cytotoxicity and elevated pro-apoptotic genes in CD19-positive leukemia B-cells without inducing cell death in CD19-negative cells. Overall, the novel CD19 CAR exosomes target the CD19 surface antigens of leukemic B-cells and can induce contact-dependent cytotoxicity.

[Medium-term follow-up of patients treated with chimeric antigen receptor T cells (CAR T cells): Recommendations of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

Chimeric antigen receptor (CAR) T cells are a new class of anti-cancer therapy that involves manipulating autologous or allogeneic T cells to express a CAR directed against a membrane antigen. In Europe, tisagenlecleucel (Kymriah™) has marketing authorization for the treatment of relapsed / refractory acute lymphoblastic leukemia (ALL) in children and young adults, in addition to the treatment of relapsed/refractory diffuse large B-cell lymphoma (DLBCL); the marketing authorization for axicabtagene ciloleucel (Yescarta™) is for the treatment of relapsed / refractory high-grade B-cell lymphoma and for the treatment of primary mediastinal B-cell lymphoma. Both cell products are genetically modified autologous T cells directed against CD19. These recommendations, drawn up by a working group of the Francophone Society of Bone Marrow transplantation and cellular Therapy (SFGM-TC) relate to the management of patients and the supply chain: medium-term complications, in particular cytopenias and B-cell aplasia, nursing and psychological supportive care. In another work, we will address long-term monitoring, post-marketing authorization pharmacovigilance and issues relating to JACIE and regulatory authorities. These recommendations are not prescriptive; their aim is to provide guidelines for the use of this new therapeutic approach. The purpose of this workshop is to outline the organizational aspects of this new therapeutic approach.

Insights on Droplet Digital PCR-Based Cellular Kinetics and Biodistribution Assay Support for CAR-T Cell Therapy

Characterizing in vivo cellular kinetics and biodistribution of chimeric antigen receptor T (CAR-T) cells is critical for toxicity assessment, nonclinical and clinical efficacy studies. To date, the standardized assay to characterize CAR-T cell distribution, expansion, contraction, and persistence profiles is not readily available. To overcome this limitation and increase comparability among studies, we have established a universal protocol for analysis. We established a duplexing ddPCR protocol for the CAR-T transgene and reference gene to normalize the genomic DNA input prepared from mouse blood and tissues. The high-throughput gDNA extraction method enabled highly reproducible gDNA extraction while eliminating labor-intensive steps. The investigational CAR-T cells were intravenously injected into immunodeficient mice bearing human colorectal cancer xenografts. The blood and tissue samples were collected to measure the cellular kinetics by ddPCR and flow cytometry. The standard curves were linear throughout the calibration range with acceptable intra- and inter-day precision and accuracy. The gDNA recovery study performed by spiking in the exo-gene plasmid DNA or CAR-T cells revealed that the recovery ranged from 60 to 100% in blood and tissue homogenates. The use of both units of copy/μg gDNA and copy/μL blood met the current regulatory requirement and allowed for a systematic understanding of CAR-T cell expansion and a direct comparison with the flow cytometry data. A standardized ddPCR assay, including automated gDNA extraction procedures, has been established for evaluating cellular kinetics and biodistribution in CAR-T cell therapies.

Improving and Maintaining Responses in Pediatric B-Cell Acute Lymphoblastic Leukemia Chimeric Antigen Receptor-T Cell Therapy

ABSTRACT

Chimeric antigen receptor T therapy has heralded a new era in the treatment of acute lymphoblastic leukemia (ALL) and other hematologic malignancies. In this autologous immunotherapy, patient-derived T cells are genetically engineered and then infused back to kill the leukemia cells. The observed response rates in ALL are a testament to the success of this therapy. However, there have been instances where the patients either did not respond or relapsed after initial response. Emergence of resistance due to antigen loss and T-cell exhaustion has been observed. This poses a challenge in making this therapy successful for every ALL patient and warrants deeper understanding of emergence of resistance and potential approaches to overcome them. Here we discuss current perspectives and advances in this area.