Toxicity and management in CAR T-cell therapy. Mol Ther Oncolytics. 2016;3:16011. [PMID: 27626062 PMCID: PMC5008265 DOI: 10.1038/mto.2016.11]

Development of Anti-Human Mesothelin-Targeted Chimeric Antigen Receptor Messenger RNA-Transfected Peripheral Blood Lymphocytes for Ovarian Cancer Therapy

CD19-targeted chimeric antigen receptor (CAR) engineered T/natural killer (NK)-cell therapies can result in durable clinical responses in B-cell malignancies. However, CAR-based immunotherapies have been much less successful in solid cancers, in part due to "on-target off-tumor" toxicity related to expression of target tumor antigens on normal tissue. Based on preliminary observations of safety and clinical activity in proof-of-concept clinical trials, tumor antigen-specific messenger RNA (mRNA) CAR transfection into selected, activated, and expanded T/NK cells may permit prospective control of "on-target off-tumor" toxicity. To develop a commercial product for solid tumors, mesothelin was selected as an antigen target based on its association with poor prognosis and overexpression in multiple solid cancers. It was hypothesized that selecting, activating, and expanding cells ex vivo prior to mRNA CAR transfection would not be necessary, thus simplifying the complexity and cost of manufacturing. Now, the development of anti-human mesothelin mRNA CAR transfected peripheral blood lymphocytes (CARMA-hMeso) is reported, demonstrating the manufacture and cryopreservation of multiple cell aliquots for repeat administrations from a single human leukapheresis. A rapid, automated, closed system for cGMP-compliant transfection of mRNA CAR in up to 20 × 10⁹ peripheral blood lymphocytes was developed. Here we show that CARMA-hMeso cells recognize and lyse tumor cells in a mesothelin-specific manner. Expression of CAR was detectable over approximately 7 days in vitro, with a progressive decline of CAR expression that appears to correlate with in vitro cell expansion. In a murine ovarian cancer model, a single intraperitoneal injection of CARMA-hMeso resulted in the dose-dependent inhibition of tumor growth and improved survival of mice. Furthermore, repeat weekly intraperitoneal administrations of the optimal CARMA-hMeso dose further prolonged disease control and survival. No significant off-target toxicities were observed. These data support further investigation of CARMA-hMeso as a potential treatment for ovarian cancer and other mesothelin-expressing cancers.

Clinical translation and regulatory aspects of CAR/TCR-based adoptive cell therapies-the German Cancer Consortium approach

Adoptive transfer of T cells genetically modified by TCRs or CARs represents a highly attractive novel therapeutic strategy to treat malignant diseases. Various approaches for the development of such gene therapy medicinal products (GTMPs) have been initiated by scientists in recent years. To date, however, the number of clinical trials commenced in Germany and Europe is still low. Several hurdles may contribute to the delay in clinical translation of these therapeutic innovations including the significant complexity of manufacture and non-clinical testing of these novel medicinal products, the limited knowledge about the intricate regulatory requirements of the academic developers as well as limitations of funds for clinical testing. A suitable good manufacturing practice (GMP) environment is a key prerequisite and platform for the development, validation, and manufacture of such cell-based therapies, but may also represent a bottleneck for clinical translation. The German Cancer Consortium (DKTK) and the Paul-Ehrlich-Institut (PEI) have initiated joint efforts of researchers and regulators to facilitate and advance early phase, academia-driven clinical trials. Starting with a workshop held in 2016, stakeholders from academia and regulatory authorities in Germany have entered into continuing discussions on a diversity of scientific, manufacturing, and regulatory aspects, as well as the benefits and risks of clinical application of CAR/TCR-based cell therapies. This review summarizes the current state of discussions of this cooperative approach providing a basis for further policy-making and suitable modification of processes.

Genetically enhanced T lymphocytes and the intensive care unit

Chimeric antigen receptor-modified T cells (CAR-T cells) and donor lymphocyte infusion (DLI) are important protocols in lymphocyte engineering. CAR-T cells have emerged as a new modality for cancer immunotherapy due to their potential efficacy against hematological malignancies. These genetically modified receptors contain an antigen-binding moiety, a hinge region, a transmembrane domain, and an intracellular costimulatory domain resulting in lymphocyte T cell activation subsequent to antigen binding. In present-day medicine, four generations of CAR-T cells are described depending on the intracellular signaling domain number of T cell receptors. DLI represents a form of adoptive therapy used after hematopoietic stem cell transplant for its anti-tumor and anti-infectious properties. This article covers the current status of CAR-T cells and DLI research in the intensive care unit (ICU) patient, including the efficacy, toxicity, side effects and treatment.

Advances in the use of natural receptor- or ligand-based chimeric antigen receptors (CARs) in haematologic malignancies

Chimeric antigen receptors (CAR)-T cell therapy has recently made promising advances towards treatment of B-cell malignancies. This approach makes use of an antibody-derived single chain variable fragment (scFv)-based CAR to target the CD19 antigen. Currently scFvs are the most common strategy for creation of CARs, but tumor cells can also be targeted using non-antibody based approaches with designs focused on the interaction between natural receptors and their ligands. This emerging strategy has been used in unique ways to target multiple tumor types, including solid and haematological malignancies. In this review, we will highlight the performance of receptor-ligand combinations as designs for CARs to treat cancer, with a particular focus on haematologic malignancies.

A Rapamycin-Activated Caspase 9-Based Suicide Gene

Engineered T cell therapies show considerable promise in the treatment of refractory malignancies. Given the ability of engineered T cells to engraft and persist for prolonged periods along with unpredicted toxicities, incorporation of a suicide gene to allow selective depletion after administration is desirable. Rapamycin is a safe and widely available immunosuppressive pharmaceutical that acts by heterodimerization of FKBP12 with the FRB fragment of mTOR. The apical caspase caspase 9 is activated by homodimerization through its CARD domain. We developed a rapamycin-induced caspase 9 suicide gene. First, we showed that caspase 9 could be activated by a two-protein format with replacement of the CARD domain with both FRB and FKBP12. We next identified an optimal compact single-protein rapamycin caspase 9 (rapaCasp9) by fusing both FRB and FKBP12 with the catalytic domain of caspase 9. Functionality of rapaCasp9 when co-expressed with a CD19 CAR was demonstrated in vitro and in vivo.

CD8+ T Cells and NK Cells: Parallel and Complementary Soldiers of Immunotherapy

CD8+ T cells and NK cells are both cytotoxic effector cells of the immune system, but the recognition, specificity, sensitivity, and memory mechanisms are drastically different. While many of these topics have been extensively studied in CD8+ T cells, very little is known about NK cells. Current cancer immunotherapies mainly focus on CD8+ T cells, but have many issues of toxicity and efficacy. Given the heterogeneous nature of cancer, personalized cancer immunotherapy that integrates the power of both CD8+ T cells in adaptive immunity and NK cells in innate immunity might be the future direction, along with precision targeting and effective delivery of tumor-specific, memory CD8+ T cells and NK cells.

Autoimmune Neurologic Disorders

The practice of autoimmune neurology focuses on the diagnosis and treatment of a wide spectrum of neurological conditions driven by abnormal immune responses directed against neural tissues. These include autoimmune, paraneoplastic, postinfectious, and iatrogenic conditions. Symptoms of autoimmune neurologic disorders can be diverse and often difficult to recognize in their early stages, complicating the diagnosis. This review discusses the classification and management of common autoimmune neurological conditions, placing an emphasis on the rapid identification of autoimmune etiology and mechanism of immune dysfunction to allow for the timely institution of appropriate treatment.

Chimeric Antigen Receptor T-Cells for the Treatment of B-Cell Acute Lymphoblastic Leukemia

Chimeric antigen receptor (CAR) T-cell technology has seen a rapid development over the last decade mostly due to the potential that these cells may have in treating malignant diseases. It is a generally accepted principle that very few therapeutic compounds deliver a clinical response without treatment-related toxicity, and studies have shown that CAR T-cells are not an exception to this rule. While large multinational drug companies are currently investigating the potential role of CAR T-cells in hematological oncology, the potential of such cellular therapies are being recognized worldwide as they are expected to expand in the patient to support the establishment of the immune memory, provide a continuous surveillance to prevent and/or treat a relapse, and keep the targeted malignant cell subpopulation in check. In this article, we present the possible advantages of using CAR T-cells in treating acute lymphoblastic leukemia, presenting the technology and the current knowledge in their preclinical and early clinical trial use. Thus, this article first presents the main present-day knowledge on the standard of care for acute lymphoblastic leukemia. Afterward, current knowledge is presented about the use of CAR T-cells in cancer immunotherapy, describing their design, the molecular constructs, and the preclinical data on murine models to properly explain the background for their clinical use. Last, but certainly not least, this article presents the use of CAR T-cells for the immunotherapy of B-cell acute lymphoblastic leukemia, describing both their potential clinical advantages and the possible side effects.

A guide to manufacturing CAR T cell therapies

In recent years, chimeric antigen receptor (CAR) modified T cells have been used as a treatment for haematological malignancies in several phase I and II trials and with Kymriah of Novartis and Yescarta of KITE Pharma, the first CAR T cell therapy products have been approved. Promising clinical outcomes have yet been tempered by the fact that many therapies may be prohibitively expensive to manufacture. The process is not yet defined, far from being standardised and often requires extensive manual handling steps. For academia, big pharma and contract manufacturers it is difficult to obtain an overview over the process strategies and their respective advantages and disadvantages. This review details current production processes being used for CAR T cells with a particular focus on efficacy, reproducibility, manufacturing costs and release testing. By undertaking a systematic analysis of the manufacture of CAR T cells from reported clinical trial data to date, we have been able to quantify recent trends and track the uptake of new process technology. Delivering new processing options will be key to the success of the CAR-T cells ensuring that excessive manufacturing costs do not disrupt the delivery of exciting new therapies to the wide possible patient cohort.

CAR T-cells for cancer therapy

Chimeric antigen receptor (CAR) T-cells are redirected T-cells that can recognize cancer antigens in a major histocompatibility complex (MHC)-independent fashion. A typical CAR is comprised of two main functional domains: an extracellular antigen recognition domain, called a single-chain variable fragment (scFv), and an intracellular signaling domain. Based on the number of intracellular signaling molecules, CARs are categorized into four generations. CAR T-cell therapy has become a promising treatment for hematologic malignancies. However, results of its clinical trials on solid tumors have not been encouraging. Here, we described the structure of CARs and summarized the clinical trials of CD19-targeted CAR T-cells. The side effects, safety management, challenges, and future prospects of CAR T-cells for the treatment of cancer, particularly for solid tumors, were also discussed.

Adverse Effects Associated with Clinical Applications of CAR Engineered T Cells

Cancer has been ranked as the second leading cause of death in the United States. To reduce cancer mortality, immunotherapy is gaining momentum among other therapeutic modalities, due to its impressive results in clinical trials. The genetically engineered T cells expressing chimeric antigen receptors (CARs) are emerging as a new approach in cancer immunotherapy, with the most successful outcomes in the refractory/relapse hematologic malignancies. However, the widespread clinical applications are limited by adverse effects some of which are life-threatening. Strategies to reduce the chance of side effects as well as close monitoring, rapid diagnosis and proper treatment of side effects are necessary to take the most advantages of this valuable therapy. Here we review the reported toxicities associated with CAR engineered T cells, the strategies to ameliorate the toxicity, and further techniques and designs leading to a safer CAR T-cell therapy.

Bioengineering Solutions for Manufacturing Challenges in CAR T Cells

The next generation of therapeutic products to be approved for the clinic is anticipated to be cell therapies, termed "living drugs" for their capacity to dynamically and temporally respond to changes during their production ex vivo and after their administration in vivo. Genetically engineered chimeric antigen receptor (CAR) T cells have rapidly developed into powerful tools to harness the power of immune system manipulation against cancer. Regulatory agencies are beginning to approve CAR T cell therapies due to their striking efficacy in treating some hematological malignancies. However, the engineering and manufacturing of such cells remains a challenge for widespread adoption of this technology. Bioengineering approaches including biomaterials, synthetic biology, metabolic engineering, process control and automation, and in vitro disease modeling could offer promising methods to overcome some of these challenges. Here, we describe the manufacturing process of CAR T cells, highlighting potential roles for bioengineers to partner with biologists and clinicians to advance the manufacture of these complex cellular products under rigorous regulatory and quality control.

Cord blood NK cells engineered to express IL-15 and a CD19-targeted CAR show long-term persistence and potent antitumor activity

Chimeric antigen receptors (CARs) have been used to redirect the specificity of autologous T cells against leukemia and lymphoma with promising clinical results. Extending this approach to allogeneic T cells is problematic as they carry a significant risk of graft-versus-host disease (GVHD). Natural killer (NK) cells are highly cytotoxic effectors, killing their targets in a non-antigen-specific manner without causing GVHD. Cord blood (CB) offers an attractive, allogeneic, off-the-self source of NK cells for immunotherapy. We transduced CB-derived NK cells with a retroviral vector incorporating the genes for CAR-CD19, IL-15 and inducible caspase-9-based suicide gene (iC9), and demonstrated efficient killing of CD19-expressing cell lines and primary leukemia cells in vitro, with marked prolongation of survival in a xenograft Raji lymphoma murine model. Interleukin-15 (IL-15) production by the transduced CB-NK cells critically improved their function. Moreover, iC9/CAR.19/IL-15 CB-NK cells were readily eliminated upon pharmacologic activation of the iC9 suicide gene. In conclusion, we have developed a novel approach to immunotherapy using engineered CB-derived NK cells, which are easy to produce, exhibit striking efficacy and incorporate safety measures to limit toxicity. This approach should greatly improve the logistics of delivering this therapy to large numbers of patients, a major limitation to current CAR-T-cell therapies.

Use of cord blood derived T-cells in cancer immunotherapy: milestones achieved and future perspectives

INTRODUCTION

Hematopoietic cell transplantation is a potentially lifesaving procedure for patients with hematological malignancies who are refractory to conventional chemotherapy and/or irradiation treatment. Umbilical cord blood (CB) transplantation, as a hematopoietic stem and progenitor cell (HSPC) source, has several advantages over bone marrow transplantation with respect to matching and prompt availability for transplantation. Additionally, CB has some inherent features, such as rapid expansion of T cells, lower prevalence of graft-versus-host disease and higher graft versus tumor efficacy that make this HSPC cell source more favorable over other HSPC sources. Areas covered: This review summarizes the current CB and CB derived T cell applications aiming to better disease control for hematological malignancies and discusses future directions to more effective therapies. Expert commentary: CB transplantation could be used as a platform to extract cord blood derived T cells for ex vivo expansion and/or gene modification to improve cellular immunotherapies. In addition, combining cord blood gene-engineered T cell products with vaccination strategies, such as cord blood derived dendritic cell based vaccines, may provide synergistic immunotherapies with enhanced anti-tumor effects.

Current state and future prospects of immunotherapy for glioma

There is a large unmet need for effective therapeutic approaches for glioma, the most malignant brain tumor. Clinical and preclinical studies have enormously expanded our knowledge about the molecular aspects of this deadly disease and its interaction with the host immune system. In this review we highlight the wide array of immunotherapeutic interventions that are currently being tested in glioma patients. Given the molecular heterogeneity, tumor immunoediting and the profound immunosuppression that characterize glioma, it has become clear that combinatorial approaches targeting multiple pathways tailored to the genetic signature of the tumor will be required in order to achieve optimal therapeutic efficacy.

Biotherapeutics in non-clinical development: Strengthening the interface between safety, pharmacokinetics-pharmacodynamics and manufacturing

Biological drugs comprise a wide field of different modalities with respect to structure, pharmacokinetics and pharmacological function. Considerable non-clinical experience in the development of proteins (e.g. insulin) and antibodies has been accumulated over the past thirty years. In order to improve the efficacy and the safety of these biotherapeutics, Fc modifications (e.g. Fc silent antibody versions), combinations (antibody-drug conjugates, protein-nanoparticle combinations), and new constructs (darpins, fynomers) have been introduced. In the last decade, advanced therapy medicinal products (ATMPs) in research and development have become a considerable and strongly growing part of the biotherapeutic portfolio. ATMPs consisting of gene and cell therapy modalities or even combinations of them, further expand the level of complexity, which already exists in non-clinical development strategies for biological drugs and has thereby led to a further diversification of expertise in safety and PKPD assessment of biological drugs. It is the fundamental rationale of the BioSafe meetings, held yearly in the EU and in the US, to convene experts on a regular basis and foster knowledge exchange and mutual understanding in this fast growing area. In order to reflect at least partially the variety of the biotherapeutics field, the 2016 EU BioSafe meeting addressed the following topics in six sessions: (i) In vitro Meets in vivo to Leverage Biologics Development (ii) New developments and regulatory considerations in the cell and gene therapy field (iii) CMC Challenges with Biologics development (iv) Minipigs in non-clinical safety assessment (v) Opportunities of PKPD Assessment in Less Common Administration Routes In the breakout sessions the following questions were discussed: (i) Cynomolgus monkey as a reprotoxicology Species: Impact of Immunomodulators on Early Pregnancy Maintenance (ii) Safety Risk of Inflammation and Autoimmunity Induced by Immunomodulators (iii) Experience with non-GMP Material in Pivotal Non-clinical Safety Studies to Support First in Man (FiM) Trials (iv) Safety Assessment of Combination Products for Non-oncology.

Reprogramming T-cells for adoptive immunotherapy of ovarian cancer

INTRODUCTION

Epithelial ovarian cancer (EOC) is the most common cause of death among gynecological malignancies. Despite surgical and pharmacological efforts to improve patients' outcome, persistent and recurrent EOC remains an un-eradicable disease. Chimeric associated antigens (CAR) T cells are T lymphocytes expressing an engineered T cell receptor that activate the immune response after an MHC unrestricted recognition of specific antigens, including tumor associated antigens (TAAs). CART cells have been shown to be effective in the treatment of hematologic tumors even if frequently associated with potentially severe toxicity and high production costs.

AREAS COVERED

In this review, we will focus on preclinical and clinical studies evaluating CART activity in EOC in order to identify possible difficulties and advantages of their use in this particular setting.

EXPERT OPINION

The pattern of diffusion within the peritoneal cavity, the tumor microenvironment and the high rate of TAAs make EOC a particularly interesting model for CART cells use. Data from preclinical studies indicate a potential activity of CARTs in EOC, but robust clinical data are still awaited. Further studies are needed to determine the best methods of administration and the most effective CAR type to treat EOC patients.

Methods of Controlling Invasive Fungal Infections Using CD8+ T Cells

Invasive fungal infections (IFIs) cause high rates of morbidity and mortality in immunocompromised patients. Pattern-recognition receptors present on the surfaces of innate immune cells recognize fungal pathogens and activate the first line of defense against fungal infection. The second line of defense is the adaptive immune system which involves mainly CD4+ T cells, while CD8+ T cells also play a role. CD8+ T cell-based vaccines designed to prevent IFIs are currently being investigated in clinical trials, their use could play an especially important role in acquired immune deficiency syndrome patients. So far, none of the vaccines used to treat IFI have been approved by the FDA. Here, we review current and future antifungal immunotherapy strategies involving CD8+ T cells. We highlight recent advances in the use of T cells engineered using a Sleeping Beauty vector to treat IFIs. Recent clinical trials using chimeric antigen receptor (CAR) T-cell therapy to treat patients with leukemia have shown very promising results. We hypothesized that CAR T cells could also be used to control IFI. Therefore, we designed a CAR that targets β-glucan, a sugar molecule found in most of the fungal cell walls, using the extracellular domain of Dectin-1, which binds to β-glucan. Mice treated with D-CAR+ T cells displayed reductions in hyphal growth of Aspergillus compared to the untreated group. Patients suffering from IFIs due to primary immunodeficiency, secondary immunodeficiency (e.g., HIV), or hematopoietic transplant patients may benefit from bioengineered CAR T cell therapy.

Breakthroughs in modern cancer therapy and elusive cardiotoxicity: Critical research-practice gaps, challenges, and insights

To date, five cancer treatment modalities have been defined. The three traditional modalities of cancer treatment are surgery, radiotherapy, and conventional chemotherapy, and the two modern modalities include molecularly targeted therapy (the fourth modality) and immunotherapy (the fifth modality). The cardiotoxicity associated with conventional chemotherapy and radiotherapy is well known. Similar adverse cardiac events are resurging with the fourth modality. Aside from the conventional and newer targeted agents, even the most newly developed, immune-based therapeutic modalities of anticancer treatment (the fifth modality), e.g., immune checkpoint inhibitors and chimeric antigen receptor (CAR) T-cell therapy, have unfortunately led to potentially lethal cardiotoxicity in patients. Cardiac complications represent unresolved and potentially life-threatening conditions in cancer survivors, while effective clinical management remains quite challenging. As a consequence, morbidity and mortality related to cardiac complications now threaten to offset some favorable benefits of modern cancer treatments in cancer-related survival, regardless of the oncologic prognosis. This review focuses on identifying critical research-practice gaps, addressing real-world challenges and pinpointing real-time insights in general terms under the context of clinical cardiotoxicity induced by the fourth and fifth modalities of cancer treatment. The information ranges from basic science to clinical management in the field of cardio-oncology and crosses the interface between oncology and onco-pharmacology. The complexity of the ongoing clinical problem is addressed at different levels. A better understanding of these research-practice gaps may advance research initiatives on the development of mechanism-based diagnoses and treatments for the effective clinical management of cardiotoxicity.

Chimeric antigen receptor T-cell therapy - assessment and management of toxicities

Immunotherapy using T cells genetically engineered to express a chimeric antigen receptor (CAR) is rapidly emerging as a promising new treatment for haematological and non-haematological malignancies. CAR-T-cell therapy can induce rapid and durable clinical responses, but is associated with unique acute toxicities, which can be severe or even fatal. Cytokine-release syndrome (CRS), the most commonly observed toxicity, can range in severity from low-grade constitutional symptoms to a high-grade syndrome associated with life-threatening multiorgan dysfunction; rarely, severe CRS can evolve into fulminant haemophagocytic lymphohistiocytosis (HLH). Neurotoxicity, termed CAR-T-cell-related encephalopathy syndrome (CRES), is the second most-common adverse event, and can occur concurrently with or after CRS. Intensive monitoring and prompt management of toxicities is essential to minimize the morbidity and mortality associated with this potentially curative therapeutic approach; however, algorithms for accurate and consistent grading and management of the toxicities are lacking. To address this unmet need, we formed a CAR-T-cell-therapy-associated TOXicity (CARTOX) Working Group, comprising investigators from multiple institutions and medical disciplines who have experience in treating patients with various CAR-T-cell therapy products. Herein, we describe the multidisciplinary approach adopted at our institutions, and provide recommendations for monitoring, grading, and managing the acute toxicities that can occur in patients treated with CAR-T-cell therapy.

Chimeric antigen receptor T-cell therapies for multiple myeloma

Multiple myeloma (MM) is a nearly always incurable malignancy of plasma cells, so new approaches to treatment are needed. T-cell therapies are a promising approach for treating MM, with a mechanism of action different than those of standard MM treatments. Chimeric antigen receptors (CARs) are fusion proteins incorporating antigen-recognition domains and T-cell signaling domains. T cells genetically engineered to express CARs can specifically recognize antigens. Success of CAR-T cells (CAR-Ts) against leukemia and lymphoma has encouraged development of CAR-T therapies for MM. Target antigens for CARs must be expressed on malignant cells, but expression on normal cells must be absent or limited. B-cell maturation antigen is expressed by normal and malignant plasma cells. CAR-Ts targeting B-cell maturation antigen have demonstrated significant antimyeloma activity in early clinical trials. Toxicities in these trials, including cytokine release syndrome, have been similar to toxicities observed in CAR-T trials for leukemia. Targeting postulated CD19+ myeloma stem cells with anti-CD19 CAR-Ts is a novel approach to MM therapy. MM antigens including CD138, CD38, signaling lymphocyte-activating molecule 7, and κ light chain are under investigation as CAR targets. MM is genetically and phenotypically heterogeneous, so targeting of >1 antigen might often be required for effective treatment of MM with CAR-Ts. Integration of CAR-Ts with other myeloma therapies is an important area of future research. CAR-T therapies for MM are at an early stage of development but have great promise to improve MM treatment.

A safe and highly efficient tumor-targeted type I interferon immunotherapy depends on the tumor microenvironment

Despite approval for the treatment of various malignancies, clinical application of cytokines such as type I interferon (IFN) is severely impeded by their systemic toxicity. AcTakines (Activity-on-Target cytokines) are optimized immunocytokines that, when injected in mice, only reveal their activity upon cell-specific impact. We here show that type I IFN-derived AcTaferon targeted to the tumor displays strong antitumor activity without any associated toxicity, in contrast with wild type IFN. Treatment with CD20-targeted AcTaferon of CD20⁺ lymphoma tumors or melanoma tumors engineered to be CD20⁺, drastically reduced tumor growth. This antitumor effect was completely lost in IFNAR- or Batf3-deficient mice, and depended on IFN signaling in conventional dendritic cells. Also the presence of, but not the IFN signaling in, CD8⁺ T lymphocytes was critical for proficient antitumor effects. When combined with immunogenic chemotherapy, low-dose TNF, or immune checkpoint blockade strategies such as anti-PDL1, anti-CTLA4 or anti-LAG3, complete tumor regressions and subsequent immunity (memory) were observed, still without any concomitant morbidity, again in sharp contrast with wild type IFN. Interestingly, the combination therapy of tumor-targeted AcTaferon with checkpoint inhibiting antibodies indicated its ability to convert nonresponding tumors into responders. Collectively, our findings demonstrate that AcTaferon targeted to tumor-specific surface markers may provide a safe and generic addition to cancer (immuno)therapies.

Precision medicine for urothelial bladder cancer: update on tumour genomics and immunotherapy

Effective management of advanced urothelial bladder cancer is challenging. New discoveries that improve our understanding of molecular bladder cancer subtypes have revealed numerous potentially targetable genomic alterations and demonstrated the efficacy of treatments that harness the immune system. These findings have begun to change paradigms of bladder cancer therapy. For example, DNA repair pathway mutations in genes such as ERCC2, FANCC, ATM, RB1, and others can predict responses to neoadjuvant platinum-based chemotherapies and to targeted therapies on the basis of mutation status. Furthermore, an increasing number of pan-cancer clinical trials (commonly referred to as basket or umbrella trials) are enrolling patients on the basis of molecular and genetic predictors of response. These studies promise to provide improved insight into the true utility of personalized medicine in the treatment of bladder cancer and many other cancer types. Finally, therapies that modulate immune responses have shown great benefit in many cancer types. Several immune checkpoint inhibitors that target programmed cell death protein 1 (PD1), its ligand PDL1, and cytotoxic T lymphocyte-associated protein 4 (CTLA4) have already been approved for use in bladder cancer, representing the most important change to the urological oncologist's tool-kit in over a decade. These advances also provide opportunities for personalization of bladder cancer therapy.

Nonimmune cells equipped with T-cell-receptor-like signaling for cancer cell ablation

The ability to engineer custom cell-contact-sensing output devices into human non-immune cells would be useful for extending the applicability of cell-based cancer therapies and avoiding risks associated with engineered immune cells. Here, we have developed a new class of synthetic T-cell receptor-like signal-transduction device that functions efficiently in human non-immune cells and triggers release of output molecules specifically upon sensing contact with a target cell. This device employs an interleukin signaling cascade, whose OFF/ON switching is controlled by biophysical segregation of a transmembrane signal-inhibitory protein from the sensor cell/target cell interface. We further showed that designer non-immune cells equipped with this device driving expression of a membrane-penetrator/prodrug-activating enzyme construct could specifically kill target cells in the presence of the prodrug, indicating its potential usefulness for target-cell-specific, cell-based enzyme-prodrug cancer therapy. Our study also contributes to advancement of synthetic biology by extending available design principles to transmit extracellular information to cells.

Study protocol for THINK: a multinational open-label phase I study to assess the safety and clinical activity of multiple administrations of NKR-2 in patients with different metastatic tumour types

INTRODUCTION

NKR-2 are autologous T cells genetically modified to express a chimeric antigen receptor (CAR) comprising a fusion of the natural killer group 2D (NKG2D) receptor with the CD3ζ signalling domain, which associates with the adaptor molecule DNAX-activating protein of 10 kDa (DAP10) to provide co-stimulatory signal upon ligand binding. NKG2D binds eight different ligands expressed on the cell surface of many tumour cells and which are normally absent on non-neoplastic cells. In preclinical studies, NKR-2 demonstrated long-term antitumour activity towards a breadth of tumour indications, with maximum efficacy observed after multiple NKR-2 administrations. Importantly, NKR-2 targeted tumour cells and tumour neovasculature and the local tumour immunosuppressive microenvironment and this mechanism of action of NKR-2 was established in the absence of preconditioning.

METHODS AND ANALYSIS

This open-label phase I study will assess the safety and clinical activity of NKR-2 treatment administered three times, with a 2-week interval between each administration in different tumour types. The study will contain two consecutive segments: a dose escalation phase followed by an expansion phase. The dose escalation study involves two arms, one in solid tumours (five specific indications) and one in haematological tumours (two specific indications) and will include three dose levels in each arm: 3×10⁸, 1×10⁹ and 3×10⁹ NKR-2 per injection. On the identification of the recommended dose in the first segment, based on dose-limiting toxicity occurrences, the study will expand to seven different cohorts examining the seven different tumour types separately. Clinical responses will be determined according to standard Response Evaluation Criteria In Solid Tumors (RECIST) criteria for solid tumours or international working group response criteria in haematological tumours.

ETHICS APPROVAL AND DISSEMINATION

Ethical approval has been obtained at all sites. Written informed consent will be taken from all participants. The results of this study will be disseminated through presentation at international scientific conferences and reported in peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

NCT03018405, EudraCT 2016-003312-12; Pre-result.

A review of immune therapy in cancer and a question: can thermal therapy increase tumor response?

Immune therapy is a successful cancer treatment coming into its own. This is because checkpoint molecules, adoptive specific lymphocyte transfer and chimeric antigen T-cell (CAR-T) therapy are able to induce more durable responses in an increasing number of malignancies compared to chemotherapy. In addition, immune therapies are able to treat bulky disease, whereas standard cytotoxic therapies cannot treat large tumour burdens. Checkpoint inhibitor monoclonal antibodies are becoming widely used in the clinic and although more complex, adoptive lymphocyte transfer and CAR-T therapies show promise. We are learning that there are nuances to predicting the successful use of the checkpoint inhibitors as well as to specific-antigen adoptive and CAR-T therapies. We are also newly aware of a here-to-fore unrealised natural force, the status of the microbiome. However, despite better understanding of mechanisms of action of the new immune therapies, the best responses to the new immune therapies remain 20-30%. Likely the best way to improve this somewhat low response rate for patients is to increase the patient's own immune response. Thermal therapy is a way to do this. All forms of thermal therapy, from fever-range systemic thermal therapy, to high-temperature HIFU and even cryotherapy improve the immune response pre-clinically. It is time to test the immune therapies with thermal therapy in vivo to test for optimal timing of the combinations that will best enhance tumour response and then to begin to test the immune therapies with thermal therapy in the clinic as soon as possible.

Engineered Tolerance: Tailoring Development, Function, and Antigen-Specificity of Regulatory T Cells

Regulatory T cells (Tregs) are potent suppressors of immune responses and are currently being clinically tested for their potential to stop or control undesired immune responses in autoimmunity, hematopoietic stem cell transplantation, and solid organ transplantation. Current clinical approaches aim to boost Tregs in vivo either by using Treg-promoting small molecules/proteins and/or by adoptive transfer of expanded Tregs. However, the applicability of Treg-based immunotherapies continues to be hindered by technical limitations related to cell isolation and expansion of a pure, well-characterized, and targeted Treg product. Efforts to overcome these limitations and improve Treg-directed therapies are now under intense investigation in animal models and pre-clinical studies. Here, we review cell and protein engineering-based approaches that aim to target different aspects of Treg biology including modulation of IL-2 signaling or FOXP3 expression, and targeted antigen-specificity using transgenic T cell receptors or chimeric antigen receptors. With the world-wide interest in engineered T cell therapy, these exciting new approaches have the potential to be rapidly implemented and developed into therapies that can effectively fine-tune immune tolerance.

PD-1/PD-L1 inhibitors in haematological malignancies: update 2017

The introduction of PD-1/PD-L1 pathway inhibitors is an important landmark in solid oncology with unprecedented practice-changing activity in various types of solid tumours. Among haematological malignancies, PD-1/PD-L1 inhibitors have been successful, so far, only in the treatment of classical Hodgkin lymphoma, which typically exhibits an over-expression of PD-1 ligands (PD-L1, PD-L2) due to alterations in chromosome 9p24.1. Such positive outcomes led to the US Food and Drug Administration approval of nivolumab use in relapsed Hodgkin lymphoma in 2016 as the first haematological indication. Although the results in other lymphoid malignancies have not been so striking, blockade of the PD-1/PD-L1 axis has led to meaningful responses in other lymphoma types such as diffuse large B-cell lymphoma, follicular lymphoma or several T-cell lymphomas. Monotherapy with PD-1/PD-L1 inhibitors in chronic lymphocytic leukaemia and multiple myeloma has been unsatisfactory, suggesting that a combinational approach with other synergistic drugs is needed. In the case of multiple myeloma, immunomodulatory agents together with corticosteroids represent the most promising combinations. Among myeloid malignancies, the anti-PD-1 monoclonal antibodies are examined dominantly in acute myeloid leukaemia and myelodysplastic syndromes in combination with potentially synergistic hypomethylating drugs such as 5-azacitidine, resulting in promising outcomes that warrant further investigation. We have described all available clinical results of PD-1/PD-L1 inhibitors in haematological malignancies and discussed related toxicities, as well as highlighted crucial preclinical studies in this review.

Chimeric Antigen Receptor (CAR) T-Cell Therapy for Thoracic Malignancies

Chimeric antigen receptor (CAR) T cells are patient T cells that are transduced with genetically engineered synthetic receptors to target a cancer cell surface antigen. The remarkable clinical response rates achieved by adoptive transfer of T cells that target CD19 in patients with leukemia and lymphoma have led to a growing number of clinical trials exploring CAR T-cell therapy for solid tumors. Herein, we review the evolution of adoptive T-cell therapy; highlight advances in CAR T-cell therapy for thoracic malignancies; and summarize the targets being investigated in clinical trials for patients with lung cancer, malignant pleural mesothelioma, and esophageal cancer. We further discuss the barriers to successfully translating CAR T-cell therapy for solid tumors and present strategies that have been investigated to overcome these hurdles.

Clinical trials of CAR-T cells in China

Novel immunotherapeutic agents targeting tumor-site microenvironment are revolutionizing cancer therapy. Chimeric antigen receptor (CAR)-engineered T cells are widely studied for cancer immunotherapy. CD19-specific CAR-T cells, tisagenlecleucel, have been recently approved for clinical application. Ongoing clinical trials are testing CAR designs directed at novel targets involved in hematological and solid malignancies. In addition to trials of single-target CAR-T cells, simultaneous and sequential CAR-T cells are being studied for clinical applications. Multi-target CAR-engineered T cells are also entering clinical trials. T cell receptor-engineered CAR-T and universal CAR-T cells represent new frontiers in CAR-T cell development. In this study, we analyzed the characteristics of CAR constructs and registered clinical trials of CAR-T cells in China and provided a quick glimpse of the landscape of CAR-T studies in China.

Axicabtagene ciloleucel, a first-in-class CAR T cell therapy for aggressive NHL

The development of clinically functional chimeric antigen receptor (CAR) T cell therapy is the culmination of multiple advances over the last three decades. Axicabtagene ciloleucel (formerly KTE-C19) is an anti-CD19 CAR T cell therapy in development for patients with refractory diffuse large B cell lymphoma (DLBCL), including transformed follicular lymphoma (TFL) and primary mediastinal B cell lymphoma (PMBCL). Axicabtagene ciloleucel is manufactured from patients' own peripheral blood mononuclear cells (PBMC) during which T cells are engineered to express a CAR that redirects them to recognize CD19-expressing cells. Clinical trials have demonstrated the feasibility of manufacturing axicabtagene ciloleucel in a centralized facility for use in multicenter clinical trials and have demonstrated potent antitumor activity in patients with refractory DLBCL. Main acute toxicities are cytokine release syndrome and neurologic events. Axicabtagene ciloleucel holds promise for the treatment of patients with CD19-positive malignancies, including refractory DLBCL.

A versatile pretargeting approach for tumour-selective delivery and activation of TNF superfamily members

TNFR superfamily (TNFRSF) members have important immunoregulatory functions and are of clear interest for cancer immunotherapy. Various TNFRSF agonists have been clinically evaluated, but have met with limited efficacy and/or toxicity. Recent insights indicate that 'first-generation' TNFRSF agonists lack efficacy as they do not effectively cross-link their corresponding receptor. Reversely, ubiquitous TNFRSF receptor(s) cross-linking by CD40 and Fas agonistic antibodies resulted in dose-limiting liver toxicity. To overcome these issues, we developed a novel pretargeting strategy exploiting recombinant fusion proteins in which a soluble form of TRAIL, FasL or CD40L is genetically fused to a high-affinity anti-fluorescein scFv antibody fragment (scFvFITC). Fusion proteins scFvFITC:sTRAIL and scFvFITC:sFasL induced potent target antigen-restricted apoptosis in a panel of cancer lines and in primary patient-derived cancer cells, but only when pretargeted with a relevant FITC-labelled antitumour antibody. In a similar pretargeting setting, fusion protein scFvFITC:sCD40L promoted tumour-directed maturation of immature monocyte-derived dendritic cells (iDCs). This novel tumour-selective pretargeting approach may be used to improve efficacy and/or reduce possible off-target toxicity of TNFSF ligands for cancer immunotherapy.

The ABCs of Immunotherapy for Adult Patients With B-Cell Acute Lymphoblastic Leukemia

OBJECTIVE

To review the pharmacology, efficacy, and safety of Food and Drug Administration approved and promising immunotherapy agents used in the treatment of acute lymphoblastic leukemia (ALL).

DATA SOURCES

A literature search was performed of PubMed and MEDLINE databases (1950 to July 2017) and of abstracts from the American Society of Hematology and the American Society of Clinical Oncology. Searches were performed utilizing the following key terms: rituximab, blinatumomab, inotuzumab, ofatumumab, obinutuzumab, Blincyto, Rituxan, Gazyva, Arzerra, CAR T-cell, and chimeric antigen receptor (CAR).

STUDY SELECTION/DATA EXTRACTION

Studies of pharmacology, clinical efficacy, and safety of rituximab, ofatumumab, obinutuzumab, inotuzumab, blinatumomab, and CAR T-cells in the treatment of adult patients with ALL were identified.

DATA SYNTHESIS

Conventional chemotherapy has been the mainstay in the treatment of ALL, producing cure rates of approximately 90% in pediatrics, but it remains suboptimal in adult patients. As such, more effective consolidative modalities and novel therapies for relapsed/refractory disease are needed for adult patients with ALL. In recent years, anti-CD20 antibodies, blinatumomab, inotuzumab, and CD19-targeted CAR T-cells have drastically changed the treatment landscape of B-cell ALL.

CONCLUSION

Outcomes of patients with relapsed disease are improving thanks to new therapies such as blinatumomab, inotuzumab, and CAR T-cells. Although the efficacy of these therapies is impressive, they are not without toxicity, both physical and financial. The optimal sequencing of these therapies still remains a question.

Advances in immunotherapy for pediatric acute myeloid leukemia

INTRODUCTION

Achieving better disease control in patients diagnosed with acute myeloid leukemia (AML) has proven challenging. Overall survival has been impacted by addressing treatment related mortality with focused supportive care measures. Despite this improvement, it remains difficult to induce durable leukemia remissions despite aggressive chemotherapeutic regimens. The addition of hematopoietic stem cell transplants (HSCT) has allowed further treatment intensification and provided the benefit of graft-versus-leukemia (GVL) effect. However, HSCT carries the risk of transplant related morbidities, particularly GVHD, and anti-tumor responsiveness is still suboptimal. Thus, there is a need for alternate therapies. Immunotherapy has the potential to address this need. Areas covered: Expert opinion: The elusiveness of an ideal surface antigen target together with an immunosuppressive leukemic microenvironment add to the already difficult challenge in developing AML-targeted immunotherapies. Though many hurdles remain, recent translational discovery and progressive clinical advances anticipate exciting future developments.

AREAS COVERED

This review highlights promises and challenges to immune-based therapies for AML. It aims to summarize immunotherapeutic strategies trialed in AML patients to date, inclusive of: antibodies, vaccines, and cellular therapy. It emphasizes those being used in the pediatric population, but also includes adult clinical trials and translational science that may ultimately extend to pediatric patients.

Enhanced Cancer Immunotherapy by Chimeric Antigen Receptor-Modified T Cells Engineered to Secrete Checkpoint Inhibitors

Purpose: Despite favorable responses of chimeric antigen receptor (CAR)-engineered T-cell therapy in patients with hematologic malignancies, the outcome has been far from satisfactory in the treatment of solid tumors, partially owing to the development of an immunosuppressive tumor microenvironment. To overcome this limitation, we engineered CAR T cells secreting checkpoint inhibitors (CPI) targeting PD-1 (CAR.αPD1-T) and evaluated their efficacy in a human lung carcinoma xenograft mouse model.Experimental Design: To evaluate the effector function and expansion capacity of CAR.αPD1-T cells in vitro, we measured the production of IFNγ and T-cell proliferation following antigen-specific stimulation. Furthermore, the antitumor efficacy of CAR.αPD1-T cells, CAR T cells, and CAR T cells combined with anti-PD-1 antibody was determined using a xenograft mouse model. Finally, the underlying mechanism was investigated by analyzing the expansion and functional capacity of TILs.Results: Human anti-PD-1 CPIs secreted by CAR.αPD1-T cells efficiently bound to PD-1 and reversed the inhibitory effect of PD-1/PD-L1 interaction on T-cell function. PD-1 blockade by continuously secreted anti-PD-1 attenuated the inhibitory T-cell signaling and enhanced T-cell expansion and effector function both in vitro and in vivo In the xenograft mouse model, we demonstrated that the secretion of anti-PD-1 enhanced the antitumor activity of CAR T cells and prolonged overall survival.Conclusions: With constitutive anti-PD-1 secretion, CAR.αPD1-T cells are more functional and expandable, and more efficient at tumor eradication than parental CAR T cells. Collectively, our study presents an important and novel strategy that enables CAR T cells to achieve better antitumor immunity, especially in the treatment of solid tumors. Clin Cancer Res; 23(22); 6982-92. ©2017 AACR.

Adoptive cell therapy in multiple Myeloma

INTRODUCTION

Recent breakthrough advances in Multiple Myeloma (MM) immunotherapy have been achieved with the approval of the first two monoclonal antibodies, elotuzumab and daratumumab. Adoptive cell therapy (ACT) represents yet another, maybe the most powerful modality of immunotherapy, in which allogeneic or autologous effector cells are expanded and activated ex vivo followed by their re-infusion back into patients. Infused effector cells belong to two categories: naturally occurring, non-engineered cells (donor lymphocyte infusion, myeloma infiltrating lymphocytes, deltagamma T cells) or genetically- engineered antigen-specific cells (chimeric antigen receptor T or NK cells, TCR-engineered cells). Areas covered: This review article summarizes our up-to-date knowledge on ACT in MM, its promises, and upcoming strategies to both overcome its toxicity and to integrate it into future treatment paradigms. Expert opinion: Early results of clinical studies using CAR T cells or TCR- engineered T cells in relapsed and refractory MM are particularly exciting, indicating the potential of long-term disease control or even cure. Despite several caveats including toxicity, costs and restricted availability in particular, these forms of immunotherapy are likely to once more revolutionize MM therapy.

Two is better than one: advances in pathogen-boosted immunotherapy and adoptive T-cell therapy

The recent tremendous successes in clinical trials take cancer immunotherapy into a new era and have attracted major attention from both academia and industry. Among the variety of immunotherapy strategies developed to boost patients' own immune systems to fight against malignant cells, the pathogen-based and adoptive cell transfer therapies have shown the most promise for treating multiple types of cancer. Pathogen-based therapies could either break the immune tolerance to enhance the effectiveness of cancer vaccines or directly infect and kill cancer cells. Adoptive cell transfer can induce a strong durable antitumor response, with recent advances including engineering dual specificity into T cells to recognize multiple antigens and improving the metabolic fitness of transferred cells. In this review, we focus on the recent prospects in these two areas and summarize some ongoing studies that represent potential advancements for anticancer immunotherapy, including testing combinations of these two strategies.

Chimeric antigen receptor T-cell therapy for glioblastoma

Chimeric antigen receptor (CAR) T-cell therapy has shown great promise in the treatment of hematological disease, and its utility for treatment of solid tumors is beginning to unfold. Glioblastoma continues to portend a grim prognosis and immunotherapeutic approaches are being explored as a potential treatment strategy. Identification of appropriate glioma-associated antigens, barriers to cell delivery, and presence of an immunosuppressive microenvironment are factors that make CAR T-cell therapy for glioblastoma particularly challenging. However, insights gained from preclinical studies and ongoing clinical trials indicate that CAR T-cell therapy will continue to evolve and likely become integrated with current therapeutic strategies for malignant glioma.

Chimeric antigen receptor-engineered natural killer and natural killer T cells for cancer immunotherapy

Natural killer (NK) cells of the innate immune system and natural killer T (NKT) cells, which have roles in both the innate and adaptive responses, are unique lymphocyte subsets that have similarities in their functions and phenotypes. Both cell types can rapidly respond to the presence of tumor cells and participate in immune surveillance and antitumor immune responses. This has incited interest in the development of novel cancer therapeutics based on NK and NKT cell manipulation. Chimeric antigen receptors (CARs), generated through the fusion of an antigen-binding region of a monoclonal antibody or other ligand to intracellular signaling domains, can enhance lymphocyte targeting and activation toward diverse malignancies. Most of the CAR studies have focused on their expression in T cells; however, the functional heterogeneity of CAR T cells limits their therapeutic potential and is associated with toxicity. CAR-modified NK and NKT cells are becoming more prevalent because they provide a method to direct these cells more specifically to target cancer cells, with less risk of adverse effects. This review will outline current NK and NKT cell CAR constructs and how they compare to conventional CAR T cells, and discuss future modifications that can be explored to advance adoptive cell transfer of NK and NKT cells.

Current status of chimeric antigen receptor engineered T cell-based and immune checkpoint blockade-based cancer immunotherapies

Adoptive cell therapies with chimeric antigen receptor (CAR) engineered T cells (CAR-T) and immune checkpoint inhibition (ICI)-based cancer immunotherapies have lately shown remarkable success in certain tumor types. CAR-T cell-based therapies targeting CD19 can now induce durable remissions as well as prolong disease-free survival of patients with CD19 positive treatment refractory B cell malignancies and ICI-based therapies with humanized monoclonal antibodies against the T cell inhibitory receptors CTLA-4 and PD-1 as well as against the PD-1 ligand, PD-L1, can now achieve durable remissions as well as prolongation of life of a sizeable fraction of patients with melanoma and Hodgkin's lymphoma and non-small cell cancers. Most importantly, these immuno-therapeutic treatment modalities have raised the possibility of achieving long-term "containment" as well as "cures" for certain types of cancer. While this represents major advances in cancer immunotherapy, both modalities come with considerable toxicities, including fatalities. Although more work will be needed to bring CAR-T cell-based therapies to the bedside for most major cancers and a good deal more will be needed to make ICI-alone or in combination with other treatment modalities-work more consistently and across most major cancers, these two treatment modalities stand out as superb examples of successful translation of bench research to the bedside as well as represent real progress in the field of cancer immunotherapy.

Maternal Immunization: New Perspectives on Its Application Against Non-Infectious Related Diseases in Newborns

The continuous evolution in preventive medicine has anointed vaccination a versatile, human-health improving tool, which has led to a steady decline in deaths in the developing world. Maternal immunization represents an incisive step forward for the field of vaccination as it provides protection against various life-threatening diseases in pregnant women and their children. A number of studies to improve prevention rates and expand protection against the largest possible number of infections are still in progress. The complex unicity of the mother-infant interaction, both during and after pregnancy and which involves immune system cells and molecules, is an able partner in the success of maternal immunization, as intended thus far. Interestingly, new studies have shed light on the versatility of maternal immunization in protecting infants from non-infectious related diseases, such as allergy, asthma and congenital metabolic disorders. However, barely any attempt at applying maternal immunization to the prevention of childhood cancer has been made. The most promising study reported in this new field is a recent proof of concept on the efficacy of maternal immunization in protecting cancer-prone offspring against mammary tumor progression. New investigations into the possibility of exploiting maternal immunization to prevent the onset and/or progression of neuroblastoma, one of the most common childhood malignancies, are therefore justified. Maternal immunization is presented in a new guise in this review. Attention will be focused on its versatility and potential applications in preventing tumor progression in neuroblastoma-prone offspring.

Adoptive transfer of murine T cells expressing a chimeric-PD1-Dap10 receptor as an immunotherapy for lymphoma

Adoptive transfer of T cells is a promising cancer therapy and expression of chimeric antigen receptors can enhance tumour recognition and T-cell effector functions. The programmed death protein 1 (PD1) receptor is a prospective target for a chimeric antigen receptor because PD1 ligands are expressed on many cancer types, including lymphoma. Therefore, we developed a murine chimeric PD1 receptor (chPD1) consisting of the PD1 extracellular domain fused to the cytoplasmic domain of CD3ζ. Additionally, chimeric antigen receptor therapies use various co-stimulatory domains to enhance efficacy. Hence, the inclusion of a Dap10 or CD28 co-stimulatory domain in the chPD1 receptor was compared to determine which domain induced optimal anti-tumour immunity in a mouse model of lymphoma. The chPD1 T cells secreted pro-inflammatory cytokines and lysed RMA lymphoma cells. Adoptive transfer of chPD1 T cells significantly reduced established tumours and led to tumour-free survival in lymphoma-bearing mice. When comparing chPD1 receptors containing a Dap10 or CD28 domain, both receptors induced secretion of pro-inflammatory cytokines; however, chPD1-CD28 T cells also secreted anti-inflammatory cytokines whereas chPD1-Dap10 T cells did not. Additionally, chPD1-Dap10 induced a central memory T-cell phenotype compared with chPD1-CD28, which induced an effector memory phenotype. The chPD1-Dap10 T cells also had enhanced in vivo persistence and anti-tumour efficacy compared with chPD1-CD28 T cells. Therefore, adoptive transfer of chPD1 T cells could be a novel therapy for lymphoma and inclusion of the Dap10 co-stimulatory domain in chimeric antigen receptors may induce a preferential cytokine profile and T-cell differentiation phenotype for anti-tumour therapies.

Adnectin-Based Design of Chimeric Antigen Receptor for T Cell Engineering

Although chimeric antigen receptor (CAR)-engineered T cell therapy has achieved encouraging clinical trial results for treating hematological cancers, further optimization can likely expand this therapeutic success to more patients and other cancer types. Most CAR constructs used in clinical trials incorporate single chain variable fragment (scFv) as the extracellular antigen recognition domain. The immunogenicity of nonhuman scFv could cause host rejection against CAR T cells and compromise their persistence and efficacy. The limited availability of scFvs and slow discovery of new monoclonal antibodies also limit the development of novel CAR constructs. Adnectin, a class of affinity molecules derived from the tenth type III domain of human fibronectin, can be an alternative to scFv as an antigen-binding moiety in the design of CAR molecules. We constructed adnectin-based CARs targeting epithelial growth factor receptor (EGFR) and found that compared to scFv-based CAR, T cells engineered with adnectin-based CARs exhibited equivalent cell-killing activity against target H292 lung cancer cells in vitro and had comparable antitumor efficacy in xenograft tumor-bearing mice in vivo. In addition, with optimal affinity tuning, adnectin-based CAR showed higher selectivity on target cells with high EGFR expression than on those with low expression. This new design of adnectin CARs can potentially facilitate the development of T cell immunotherapy for cancer and other diseases.

Regulation of CD4 T cells and their effects on immunopathological inflammation following viral infection

CD4 T cells help immune responses, but knowledge of how memory CD4 T cells are regulated and how they regulate adaptive immune responses and induce immunopathology is limited. Using adoptive transfer of virus-specific CD4 T cells, we show that naive CD4 T cells undergo substantial expansion following infection, but can induce lethal T helper type 1-driven inflammation. In contrast, memory CD4 T cells exhibit a biased proliferation of T follicular helper cell subsets and were able to improve adaptive immune responses in the context of minimal tissue damage. Our analyses revealed that type I interferon regulates the expansion of primary CD4 T cells, but does not seem to play a critical role in regulating the expansion of secondary CD4 T cells. Strikingly, blockade of type I interferon abrogated lethal inflammation by primary CD4 T cells following viral infection, despite that this treatment increased the numbers of primary CD4 T-cell responses. Altogether, these data demonstrate important aspects of how primary and secondary CD4 T cells are regulated in vivo, and how they contribute to immune protection and immunopathology. These findings are important for rational vaccine design and for improving adoptive T-cell therapies against persistent antigens.

Cancer immunotherapy: Breakthrough or "deja vu, all over again"?

From the application of Coley's toxin in the early 1900s to the present clinical trials using immune checkpoint regulatory inhibitors, the history of cancer immunotherapy has consisted of extremely high levels of enthusiasm after anecdotal case reports of enormous success, followed by decreasing levels of enthusiasm as the results of controlled clinical trials are available. In this review, this pattern will be documented for the various immunotherapeutic approaches over the years. The sole exception being vaccination against cancer causing viruses, which have already prevented thousands of cancers. We can only hope that the present high level of enthusiasm for the use of immune stimulation by removal of blocks to cancer immunity will be more productive than the incremental improvements using previous immunotherapies.