PD-1 deficiency is not sufficient to induce myeloid mobilization to the brain or alter the inflammatory profile during chronic neurodegeneration

Innate immune activation is a major driver of neurodegenerative disease and immune regulatory pathways could be potential targets for therapeutic intervention. Recently, Programmed cell death-1 (PD-1) immune checkpoint inhibition has been proposed to mount an IFN-γ-dependent systemic immune response, leading to the recruitment of peripheral myeloid cells to the brain and neuropathological and functional improvements in mice with Alzheimer's disease-like β-amyloid pathology. Here we investigate the impact of PD-1 deficiency on murine prion disease (ME7 strain), a model of chronic neurodegeneration. Although PD-1 was found to be increased in the brain of prion mice, the absence of PD-1 did not cause myeloid cell infiltration into the brain or major changes in the inflammatory profile. However, we observed a slight exacerbation of the behavioural phenotype of ME7 mice upon PD-1 deficiency. These results do not support the possibility of using immune checkpoint blockade as a therapeutic strategy in neurodegenerative disease.

Designing natural and synthetic immune tissues

Vaccines and immunotherapies have provided enormous improvements for public health, but there are fundamental disconnects between where most studies are performed-in cell culture and animal models-and the ultimate application in humans. Engineering immune tissues and organs, such as bone marrow, thymus, lymph nodes and spleen, could be instrumental in overcoming these hurdles. Fundamentally, designed immune tissues could serve as in vitro tools to more accurately study human immune function and disease, while immune tissues engineered for implantation as next-generation vaccines or immunotherapies could enable direct, on-demand control over generation and regulation of immune function. In this Review, we discuss recent interdisciplinary strategies that are merging materials science and immunology to create engineered immune tissues in vitro and in vivo. We also highlight the hurdles facing these approaches and the need for comparison to existing clinical options, relevant animal models, and other emerging technologies.

Cutaneous toxicity as a predictive biomarker for clinical outcome in patients receiving anticancer therapy

The relationship between treatment outcome and cutaneous toxicity induced by anticancer therapy has gained attention in the past decade. In this article, we have provided an overview of the 3 main classes of anticancer agents-specifically, molecularly targeted kinase inhibitors, immune checkpoint inhibitors, and cytotoxic chemotherapeutics-and described the data evaluating the association between cutaneous toxicity induced by these agents and survival benefit. Although preliminary studies are promising with regard to the potential role of cutaneous toxicities as a surrogate biomarker of efficacy of treatment, larger prospective studies are needed to confirm this relationship. Dermatologists have a unique opportunity to collaborate with oncologists in the multidisciplinary treatment paradigm by helping to identify and manage these dermatologic events in patients with cancer. A heightened awareness of these toxicities is critical, as it can potentially allow recognition of the efficacy of anticancer therapy and may influence treatment decisions and patient outcomes.

Small Molecules Drive Big Improvements in Immuno-Oncology Therapies

Immuno-oncology therapies have the potential to revolutionize the armamentarium of available cancer treatments. To further improve clinical response rates, researchers are looking for novel combination regimens, with checkpoint blockade being used as a backbone of the treatment. This Review highlights the significance of small molecules in this approach, which holds promise to provide increased benefit to cancer patients.

Contribution to Tumor Angiogenesis From Innate Immune Cells Within the Tumor Microenvironment: Implications for Immunotherapy

The critical role of angiogenesis in promoting tumor growth and metastasis is strongly established. However, tumors show considerable variation in angiogenic characteristics and in their sensitivity to antiangiogenic therapy. Tumor angiogenesis involves not only cancer cells but also various tumor-associated leukocytes (TALs) and stromal cells. TALs produce chemokines, cytokines, proteases, structural proteins, and microvescicles. Vascular endothelial growth factor (VEGF) and inflammatory chemokines are not only major proangiogenic factors but are also immune modulators, which increase angiogenesis and lead to immune suppression. In our review, we discuss the regulation of angiogenesis by innate immune cells in the tumor microenvironment, specific features, and roles of major players: macrophages, neutrophils, myeloid-derived suppressor and dendritic cells, mast cells, γδT cells, innate lymphoid cells, and natural killer cells. Anti-VEGF or anti-inflammatory drugs could balance an immunosuppressive microenvironment to an immune permissive one. Anti-VEGF as well as anti-inflammatory drugs could therefore represent partners for combinations with immune checkpoint inhibitors, enhancing the effects of immune therapy.

Correlation between sex and efficacy of immune checkpoint inhibitors (PD-1 and CTLA-4 inhibitors)

Immune checkpoint inhibitors (ICIs) exert the antitumor efficacy depending on immune response, which is affected by sex difference, where both biological and sociological factors are involved. The role of sex in ICI trials has been overlooked. How sex correlates with ICI efficacy is incompletely understood. Clinical trials evaluating ICI versus other therapies in male and female patients were included. The hazard ratio (HR) and 95% confidence interval (CI) of overall survival (OS) and progression-free survival (PFS) were used. Six thousand and ninety-six patients from 11 trials were included. More improvement of OS was observed in males (HR, 0.62; 95% CI, 0.53-0.71; p < 0.001) treated with ICI versus controls than females (HR, 0.74; 95% CI, 0.65-0.84; p < 0.001). ICIs improved PFS more in males (HR, 0.57; 95% CI, 0.43-0.71; p < 0.001) than females (HR, 0.71; 95% CI, 0.52-0.91; p < 0.001). The sex difference had more effect on the overall survival in melanoma patients versus NSCLC patients. Overall survival of patients treated with CTLA-4 inhibitor was more influenced by sex variable compared with PD-1 inhibitors. A significant sex-related efficacy difference was observed between female and male melanoma patients. Although male patients had longer OS and PFS than females when treated with ICIs versus controls, the difference was not significant. Sex difference should be more considered in future clinical trials, guidelines and clinical practice.

Tyrosine kinase inhibitors and immune checkpoint blockade in allogeneic hematopoietic cell transplantation

Advances in the prevention of graft-versus-host disease (GVHD) and opportunistic infection have improved survival after allogeneic hematopoietic cell transplantation (allo-HCT) in the past decade. However, few inroads have been made into the treatment or prevention of relapse of the underlying malignancy for which allo-HCT is being performed. The introduction of US Food and Drug Administration-approved agents with significant activity in a variety of hematologic malignancies provides an opportunity to evaluate these interventions in the allo-HCT setting. Some of the most promising new agents include tyrosine kinase inhibitors (TKIs) directed at bcr-abl, kinase inhibitors targeting fms-like tyrosine kinase 3, and immune checkpoint inhibitors blocking both CTLA4 and PD-1. Data have emerged indicating potential efficacy of these agents in preventing or treating relapse, though definitive evidence remains elusive. However, potential toxicity can be considerable, highlighting the need for further clinical trials to define the therapeutic window. This review explores the immunologic and clinical consequence of treatment with both TKIs and checkpoint inhibitors in the peri- and post-allo-HCT setting.

Systemic treatments for hepatocellular carcinoma: challenges and future perspectives

Sorafenib has been the only approved systemic treatment of hepatocellular carcinoma (HCC) for almost a decade. Recently, two new drugs showed positive results in two Phase III studies. The RESORCE trial identified regorafenib as a valid second-line treatment for patients progressing to sorafenib, the REFLECT trial showed that lenvatinib is noninferior to sorafenib as front-line treatment. Following these trials, the therapeutic scenario will be dominated by anti-VEGFR drugs, with three different molecules showing a proven anticancer activity. Some open problems still remain and different immunotherapy trials are underway, following promising preliminary results. In this review we analyze: the most recent advancements about patients treated with sorafenib; the results of RESORCE and REFLECT trials; and the ongoing Phase III clinical trials. Finally, we discuss how they could address the current problems and possibly reshape the future of the systemic treatments for HCC.

Phenotypic and Functional Properties of Tumor-Infiltrating Regulatory T Cells

Regulatory T (Treg) cells maintain immune homeostasis by suppressing excessive immune responses. Treg cells induce tolerance against self- and foreign antigens, thus preventing autoimmunity, allergy, graft rejection, and fetus rejection during pregnancy. However, Treg cells also infiltrate into tumors and inhibit antitumor immune responses, thus inhibiting anticancer therapy. Depleting whole Treg cell populations in the body to enhance anticancer treatments will produce deleterious autoimmune diseases. Therefore, understanding the precise nature of tumor-infiltrating Treg cells is essential for effectively targeting Treg cells in tumors. This review summarizes recent results relating to Treg cells in the tumor microenvironment, with particular emphasis on their accumulation, phenotypic, and functional properties, and targeting to enhance the efficacy of anticancer treatment.

Spatially selective depletion of tumor-associated regulatory T cells with near-infrared photoimmunotherapy

Current immunotherapies for cancer seek to modulate the balance among different immune cell populations, thereby promoting antitumor immune responses. However, because these are systemic therapies, they often cause treatment-limiting autoimmune adverse effects. It would be ideal to manipulate the balance between suppressor and effector cells within the tumor without disturbing homeostasis elsewhere in the body. CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) are well-known immunosuppressor cells that play a key role in tumor immunoevasion and have been the target of systemic immunotherapies. We used CD25-targeted near-infrared photoimmunotherapy (NIR-PIT) to selectively deplete Tregs, thus activating CD8 T and natural killer cells and restoring local antitumor immunity. This not only resulted in regression of the treated tumor but also induced responses in separate untreated tumors of the same cell line derivation. We conclude that CD25-targeted NIR-PIT causes spatially selective depletion of Tregs, thereby providing an alternative approach to cancer immunotherapy.

Chimeric antigen receptor transduced T cells: Tuning up for the next generation

Chimeric antigen receptor (CAR) T cell therapy has recently achieved impressive clinical outcome in patients with CD19-positive hematologic malignancies. Extrapolation of CAR T cell treatment to solid tumors, however, has not yet yielded similar results. This might be due to intrinsic causes, e.g. insufficient CAR T cell activation or CAR toxicity as well as extrinsic factors displaying an unfavorable tumor environment for CAR T cells by raising physical and chemical barriers. In this review, we discuss the advantages as well as major obstacles of CAR T cell therapy, particularly in the context of solid tumors, and focus on efforts and novel strategies in CAR T cell development.

Dendritic cell vaccine induces antigen-specific CD8+ T cells that are metabolically distinct from those of peptide vaccine and is well-combined with PD-1 checkpoint blockade

The success of immune checkpoint blockade has unequivocally demonstrated that anti-tumor immunity plays a pivotal role in cancer therapy. Because endogenous tumor-specific T-cell responsiveness is essential for the success of checkpoint blockade, combination therapy with cancer vaccination may facilitate tumor rejection. To select the best vaccine strategy to combine with checkpoint blockade, we compared dendritic cell-based vaccines (DC-V) with peptide vaccines for induction of anti-tumor immunity that could overcome tumor-induced immunosuppression. Using B16 melanoma and B16-specific TCR-transgenic T-cells (pmel-1), we found that DC-V efficiently primed and expanded pmel-1 cells with an active effector and central memory phenotype that were not exhausted. Vaccine-primed cells were metabolically distinct from naïve cells. DC-V-primed pmel-1 cells contained the population that shifted metabolic pathways away from glycolysis to mitochondrial oxidative phosphorylation. They displayed better effector function and proliferated more than those induced by peptide vaccination. DC-V inhibited tumor growth in prophylactic and therapeutic settings. Only DC-V but not peptide vaccine showed augmented anti-tumor activity when combined with anti-PD-1 therapy. Thus, DC-V combined with PD-1 checkpoint blockade mediates optimal anti-cancer activity in this model.

CAR T cell therapy for multiple myeloma: where are we now and where are we headed?

While recent progress has been made in the management of multiple myeloma, it remains a highly fatal malignancy especially among patients with relapsed-refractory disease. Immunotherapy with adoptive T cells targeting myeloma-associated antigens are at various stages of development and have brought about a new hope for cure. This is a review on the emerging field of adoptively transferred engineered T cell based approaches, with an in-depth focus on chimeric antigen receptors (CAR) targeting multiple myeloma. The recent results from CAR T cells targeting B cell maturation antigen are encouraging but eventual resistance to the CAR T cell therapies remain problematic. With newer approaches in therapies for multiple myeloma, the role of transplantation is evolved to form a platform for T cell therapies.

Clonality analysis of synchronous gastro-oesophageal junction carcinoma and distal gastric cancer by whole-exome sequencing

Gastro-oesophageal junction (GEJ) carcinoma and distal gastric cancer (GC) have distinct epidemiology and clinical features and their relationship is uncertain. Synchronous multiple gastric cancers located mostly at proximal and distal sites provide rare specimens for investigating the comprehensive genomic relationships among these cancers in the context of identical genetic circumstances. Formalin-fixed, paraffin-embedded (FFPE) samples from 12 patients with synchronous GEJ carcinoma and distal GC were collected in this study. Whole-exome sequencing (WES) was performed using normal tissues as a control. Mutational profiling, clonality analysis, a detailed clinico-pathological review, determination of MSI status, EBER in situ hybridization (ISH), and programmed cell death 1 (PD-1)/programmed death-ligand 1 (PD-L1) immunohistochemical staining were performed. Twenty-three of the 24 samples were microsatellite-stable (MSS). Subclonal analysis revealed that nine pairs of GEJ and distal GC tumours in neoadjuvant chemotherapy naïve patients developed independently from different origins. Two patients who received neoadjuvant chemotherapy shared clonal origins with highly similar somatic alterations. The remaining one patient who shared a rare mutation died within 6.2 months at the N3 stage. However, the enriched pathway identified from the overall mutation spectra in distal GC and GEJ carcinoma showed the close relationship of these cancers. Thus, although these cancers may have similar characteristics, histopathological and genetic profiling from single tumour specimens may still underestimate the mutational burden and somatic heterogeneity of multiple GCs. In addition, this series of cases also showed a PD-L1 expression rate of 58.3% and 66.7% in distal GC and GEJ carcinoma, respectively, with all the cases expressing PD-1. This result suggests the potential benefit of immunotherapeutic treatments. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Discovery and application of immune biomarkers for hematological malignancies

INTRODUCTION

Hematological malignancies originate and progress in primary and secondary lymphoid organs, where they establish a uniquely immune-suppressive tumour microenvironment. Although high-throughput transcriptomic and proteomic approaches are being employed to interrogate immune surveillance and escape mechanisms in patients with solid tumours, and to identify actionable targets for immunotherapy, our knowledge of the immunological landscape of hematological malignancies, as well as our understanding of the molecular circuits that underpin the establishment of immune tolerance, is not comprehensive. Areas covered: This article will discuss how multiplexed immunohistochemistry, flow cytometry/mass cytometry, proteomic and genomic techniques can be used to dynamically capture the complexity of tumour-immune interactions. Moreover, the analysis of multi-dimensional, clinically annotated data sets obtained from public repositories such as Array Express, TCGA and GEO is crucial to identify immune biomarkers, to inform the rational design of immune therapies and to predict clinical benefit in individual patients. We will also highlight how artificial neural network models and alternative methodologies integrating other algorithms can support the identification of key molecular drivers of immune dysfunction. Expert commentary: High-dimensional technologies have the potential to enhance our understanding of immune-cancer interactions and will support clinical decision making and the prediction of therapeutic benefit from immune-based interventions.

Immunotherapy of Lymphoma and Myeloma: Facts and Hopes

Immune checkpoint blockade has driven a revolution in modern oncology, and robust drug development of immune checkpoint inhibitors is underway in both solid tumors and hematologic malignancies. High response rates to programmed cell death 1 (PD-1) blockade using nivolumab or pembrolizumab in classical Hodgkin lymphoma (cHL) and several variants of non-Hodgkin lymphoma (NHL) revealed an intrinsic biological sensitivity to this approach, and work is ongoing exploring combinations with immune checkpoint inhibitors in both cHL and NHL. There are also preliminary data suggesting antitumor efficacy of PD-1 inhibitors used in combination with immunomodulatory drugs in multiple myeloma, and effects of novel monoclonal antibody therapies on the tumor microenvironment may lead to synergy with checkpoint blockade. Although immune checkpoint inhibitors are generally well tolerated, clinicians must use caution and remain vigilant when treating patients with these agents in order to identify immune-related toxicities and prevent treatment-related morbidity and mortality. Autologous stem cell transplant is a useful tool for treatment of hematologic malignancies and has potential as a platform for use of immune checkpoint inhibitors. An important safety signal has emerged surrounding the risk of graft-versus-host disease associated with use of PD-1 inhibitors before and after allogeneic stem cell transplant. We aim to discuss the facts known to date in the use of immune checkpoint inhibitors for patients with lymphoid malignancies and our hopes for expanding the benefits of immunotherapy to patients in the future. Clin Cancer Res; 24(5); 1002-10. ©2017 AACR.

Postsorafenib systemic treatments for hepatocellular carcinoma: questions and opportunities after the regorafenib trial

The search for systemic therapies for hepatocellular carcinoma has been characterized by difficulties and failures. Despite recent progresses, many issues are still to be settled. In particular, the development of drugs inhibiting different neoplastic pathways remains a priority for patients intolerant or resistant to antiangiogenic drugs. This task may be daunting, as previous failures extensively demonstrated. We aimed to identify the future perspective of postsorafenib trials analyzing the strengths and the critical points of past and currently undergoing studies, in the light of the most recent evidences in the field. We identified various points (including stratification, biomarkers, end points, radiologic criteria of response, treatment beyond radiologic progression) that should be considered by future trials to reduce the risks of failure.

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.

Cytomegalovirus vector expressing RAE-1γ induces enhanced anti-tumor capacity of murine CD8+ T cells

Designing CD8⁺ T-cell vaccines, which would provide protection against tumors is still considered a great challenge in immunotherapy. Here we show the robust potential of cytomegalovirus (CMV) vector expressing the NKG2D ligand RAE-1γ as CD8⁺ T cell-based vaccine against malignant tumors. Immunization with the CMV vector expressing RAE-1γ, delayed tumor growth or even provided complete protection against tumor challenge in both prophylactic and therapeutic settings. Moreover, a potent tumor control in mice vaccinated with this vector can be further enhanced by blocking the immune checkpoints TIGIT and PD-1. CMV vector expressing RAE-1γ potentiated expansion of KLRG1⁺ CD8⁺ T cells with enhanced effector properties. This vaccination was even more efficient in neonatal mice, resulting in the expansion and long-term maintenance of epitope-specific CD8⁺ T cells conferring robust resistance against tumor challenge. Our data show that immunomodulation of CD8⁺ T-cell responses promoted by herpesvirus expressing a ligand for NKG2D receptor can provide a powerful platform for the prevention and treatment of CD8⁺ T-cell sensitive tumors.

Mechanisms of action and rationale for the use of checkpoint inhibitors in cancer

The large family of costimulatory molecules plays a crucial role in regulation of the immune response. These molecules modulate TCR signalling via phosphorylation cascades. Some of the coinhibitory members of this family, such as PD-1 and CTLA-4, already constitute approved targets in cancer therapy and, since 2011, have opened a new area of antitumour immunotherapy. Many antibodies targeting other inhibitory receptors (Tim-3, VISTA, Lag-3 and so on) or activating costimulatory molecules (OX40, GITR and so on) are under evaluation. These antibodies have multiple mechanisms of action. At the cellular level, these antibodies restore the activation signalling pathway and reprogram T cell metabolism. Tumour cells become resistant to apoptosis when an intracellular PD-L1 signalling is blocked. CD8⁺ T cells are considered to be the main effectors of the blockade of inhibitory receptors. Certain CD8⁺ T cell subsets, such as non-hyperexhausted (CD28⁺, T-bet^high, PD-1^int), follicular-like (CXCR-5⁺) or resident memory CD8⁺ T cells, are more prone to be reactivated by anti-PD-1/PD-L1 monoclonal antibody (mAb). In the future, the challenge will be to rationally combine drugs able to make the tumour microenvironment more permissive to immunotherapy in order to potentiate its clinical activity.

Cancer immunotherapy: Opportunities and challenges in the rapidly evolving clinical landscape

Cancer immunotherapy is now established as a powerful way to treat cancer. The recent clinical success of immune checkpoint blockade (antagonists of CTLA-4, PD-1 and PD-L1) highlights both the universal power of treating the immune system across tumour types and the unique features of cancer immunotherapy. Immune-related adverse events, atypical clinical response patterns, durable responses, and clear overall survival benefit distinguish cancer immunotherapy from cytotoxic cancer therapy. Combination immunotherapies that transform non-responders to responders are under rapid development. Current challenges facing the field include incorporating immunotherapy into adjuvant and neoadjuvant cancer therapy, refining dose, schedule and duration of treatment and developing novel surrogate endpoints that accurately capture overall survival benefit early in treatment. As the field rapidly evolves, we must prioritise the development of biomarkers to guide the use of immunotherapies in the most appropriate patients. Immunotherapy is already transforming cancer from a death sentence to a chronic disease for some patients. By making smart, evidence-based decisions in developing next generation immunotherapies, cancer should become an imminently treatable, curable and even preventable disease.

Targeting natural killer cells in cancer immunotherapy

Alteration in the expression of cell-surface proteins is a common consequence of malignant transformation. Natural killer (NK) cells use an array of germline-encoded activating and inhibitory receptors that scan for altered protein-expression patterns, but tumor evasion of detection by the immune system is now recognized as one of the hallmarks of cancer. NK cells display rapid and potent immunity to metastasis or hematological cancers, and major efforts are now being undertaken to fully exploit NK cell anti-tumor properties in the clinic. Diverse approaches encompass the development of large-scale NK cell-expansion protocols for adoptive transfer, the establishment of a microenvironment favorable to NK cell activity, the redirection of NK cell activity against tumor cells and the release of inhibitory signals that limit NK cell function. In this Review we detail recent advances in NK cell-based immunotherapies and discuss the advantages and limitations of these strategies.

PD-1 and PD-L1 as emerging therapeutic targets in gastric cancer: current evidence

Gastric adenocarcinoma is a leading cause of global cancer-related morbidity and mortality, and new therapeutic approaches are needed. Despite the improved outcomes with monoclonal antibodies targeting human epidermal growth factor receptor 2 and vascular endothelial growth factor receptor 2, durable responses are uncommon. Targeting immune checkpoints including PD-1, PD-L1 and CTLA-4 have led to improved survival across several tumor types, frequently characterized by prolonged benefit in responding patients. Tumoral and lymphocyte-derived immunohistochemical staining for PD-1, PD-L1, and tumor mutational burden have shown potential as predictive response biomarkers in several tumor types. Optimal incorporation of immune-mediated therapies into gastric cancer (GC) is an area of intense ongoing investigation and benefit has been demonstrated in smaller studies of advanced patients. Important questions of biomarker selection, roles for molecular characterization, optimal combinatorial approaches, and therapeutic sequencing remain. In this study, current data are reviewed for immune checkpoint inhibitors in GC, and putative biomarkers, ongoing trials, and future considerations are discussed.

Immune checkpoint blockade for hematologic malignancies: a review

Immune checkpoint blockade has revolutionized the treatment of cancer, with impressive responses seen in a broad variety of tumor types. Blockade of immune checkpoints and immune signaling antibodies has shown promise in multiple types of hematologic malignancies (HMs), with dramatic single agent responses for pembrolizumab and nivolumab in Hodgkin lymphoma (HL). In this review, we outline the current state of immune checkpoint blockade drug development in HMs, and discuss mechanisms of activity and resistance, and highlight potential targets in the immune tumor microenvironment (TME). Blockade of T-cell checkpoint molecules PD-1/PD-L1 and CTLA-4 are the most clinically mature of the immune checkpoint strategies. Novel and upcoming strategies for immune checkpoint blockade drug development in HMs using innovative combinations to modulate immunologic targets shows significant promise as a way to expand the number of patients with blood cancers who could benefit from immunotherapy.

Vaccination with poly(IC:LC) and peptide-pulsed autologous dendritic cells in patients with pancreatic cancer

BACKGROUND

Dendritic cells (DCs) enhance the quality of anti-tumor immune response in patients with cancer. Thus, we posit that DC-based immunotherapy, in conjunction with toll-like receptor (TLR)-3 agonist poly-ICLC, is a promising approach for harnessing immunity against metastatic or locally advanced unresectable pancreatic cancer (PC).

METHODS

We generated autologous DCs from the peripheral blood of HLA-A2⁺ patients with PC. DCs were pulsed with three distinct A2-restricted peptides: 1) human telomerase reverse transcriptase (hTERT, TERT572Y), 2) carcinoembryonic antigen (CEA; Cap1-6D), and 3) survivin (SRV.A2). Patients received four intradermal injections of 1 × 10⁷ peptide-pulsed DC vaccines every 2 weeks (Day 0, 14, 28, and 42). Concurrently, patients received intramuscular administration of Poly-ICLC at 30 μg/Kg on vaccination days (i.e., day 0, 14, 28, and 42), as well as on days 3, 17, 21, 31, 37, and 45. Our key objective was to assess safety and feasibility. The effect of DC vaccination on immune response was measured at each DC injection time point by enumerating the phenotype and function of patient T cells.

RESULTS

Twelve patients underwent apheresis: nine patients with metastatic disease, and three patients with locally advanced unresectable disease. Vaccines were successfully manufactured from all individuals. We found that this treatment was well-tolerated, with the most common symptoms being fatigue and/or self-limiting flu-like symptoms. Among the eight patients who underwent imaging on day 56, four patients experienced stable disease while four patients had disease progression. The median overall survival was 7.7 months. One patient survived for 28 months post leukapheresis. MHC class I -tetramer analysis before and after vaccination revealed effective generation of antigen-specific T cells in three patients with stable disease.

CONCLUSION

Vaccination with peptide-pulsed DCs in combination with poly-ICLC is safe and induces a measurable tumor specific T cell population in patients with advanced PC.

TRIAL REGISTRATION

NCT01410968 ; Name of registry: clinicaltrials.gov; Date of registration: 08/04/2011).

Chemotherapy induces tumor immune evasion by upregulation of programmed cell death ligand 1 expression in bone marrow stromal cells

Programmed cell death ligand 1 (PD-L1) is a negative regulator of the immune response that enables tumor cells to escape T-cell immunity. Although PD-L1 expression in cancer cells has been extensively studied, the expression of PD-L1 in stromal cells and its clinical significance remain largely unknown. Here, we show that bone marrow stromal cells express a low level of PD-L1 and that this molecule is significantly upregulated by key drugs used in the treatment of lymphoma at clinically relevant concentrations. Mechanistically, chemotherapeutic drugs induce PD-L1 expression in stromal cells through upregulation of granulocyte macrophage colony-stimulating factor and activation of the extracellular signal-regulated kinase (ERK) 1/2 signaling pathway. Suppression of ERK by a chemical inhibitor or genetic silencing of ERK2 expression prevents drug-induced PD-L1 expression. PD-L1 expression is upregulated in the bone marrow stromal cells of mice treated with doxorubicin and in drug-treated bone marrow specimens from lymphoma patients. Drug-induced PD-L1 expression in stromal cells can cause significant impairment of T-cell functions. Overall, our study reveals a previously unrecognized mechanism by which chemotherapy induces tumor immune evasion by upregulation of PD-L1 in bone marrow stromal cells, and provides new evidence for the combination of chemotherapy and anti-PD-L1/PD-1 as an effective strategy for treatment of lymphoma and other cancers.

PD-1, PD-L1 (B7-H1) and Tumor-Site Immune Modulation Therapy: The Historical Perspective

The current success of targeted inhibition against cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and Programmed Death 1/Programmed Death Ligand 1 (PD-1/PD-L1, herein collectively referred to as PD) pathways is hailed as a cancer immunotherapy breakthrough. PD-L1, known also as B7 homolog 1 (B7-H1), was initially discovered by Dr. Lieping Chen in 1999. To recognize the seminal contributions by Chen to the development of PD-directed therapy against cancer, the Chinese American Hematologist and Oncologist Network (CAHON) decided to honor him with its inaugural Lifetime Achievement Award in Hematology and Oncology at the CAHON’s 2015 annual meeting. This essay chronicles the important discoveries made by Chen in the exciting field of immuno-oncology, which goes beyond his original fateful finding. It also argues that PD-directed therapy should be appropriately considered as Tumor-Site Immune Modulation Therapy to distinguish it from CTLA-4-based immune checkpoint blocking agents.

Breast Cancer Immunology and Immunotherapy: Current Status and Future Perspectives

Cancer immunology has gained renewed interest in the past few years due to emerging findings on mechanisms involved in tumoral immune evasion. Indisputably, immune edition is currently considered a critical hallmark of cancer. Basic research has revealed new targets which can be modulated in the clinical setting with new compounds and strategies. As recent evidence confirms, breast cancer (BC) is a complex and heterogeneous disease in which host immune responses play a substantial role. T-infiltrating lymphocytes measurement is suggested as a powerful new tool necessary to predict early BC evolution, especially in HER2-positive and triple negative subtypes. However, T-infiltrating lymphocytes, genomic platforms, and many other biomarkers in tissue and peripheral blood (e.g., regulatory T cells and myeloid-derived suppressor cells) are not the only factors being evaluated regarding their potential role as prognostic and/or predictive factors. Many ongoing clinical trials are exploring the activity of immune checkpoint modulators in BC treatment, both in the advanced and neoadjuvant setting. Although this field is expanding with exciting new discoveries and promising clinical results-and creating great expectations-there remain many uncertainties yet to be addressed satisfactorily before this long awaited therapeutic promise can come to fruition.

Checkpoint inhibition and cellular immunotherapy in lymphoma

Hodgkin and non-Hodgkin lymphoma are both good targets for immunotherapy, as they are accessible to antibodies and cell-based immunotherapy, express costimulatory molecules, and express lineage-restricted, viral, and unique tumor antigens. Blockade of the programmed-death 1 (PD-1) immune checkpoint has produced very encouraging response rates in patients with Hodgkin lymphoma, whereas adoptive transfer of Epstein-Barr Virus (EBV)-specific T cells has shown clinical activity in patients with posttransplant lymphoma and other EBV-associated lymphomas. T cells can also be genetically modified with chimeric antigen receptors (CARs) to confer specificity for surface antigens, and studies of CD19 CARs in lymphoma also have had encouraging response rates. Future directions include combination of checkpoint blockade and adoptive T-cell studies.

Emerging roles of p53 and other tumour-suppressor genes in immune regulation

Tumour-suppressor genes are indispensable for the maintenance of genomic integrity. Recently, several of these genes, including those encoding p53, PTEN, RB1 and ARF, have been implicated in immune responses and inflammatory diseases. In particular, the p53 tumour- suppressor pathway is involved in crucial aspects of tumour immunology and in homeostatic regulation of immune responses. Other studies have identified roles for p53 in various cellular processes, including metabolism and stem cell maintenance. Here, we discuss the emerging roles of p53 and other tumour-suppressor genes in tumour immunology, as well as in additional immunological settings, such as virus infection. This relatively unexplored area could yield important insights into the homeostatic control of immune cells in health and disease and facilitate the development of more effective immunotherapies. Consequently, tumour-suppressor genes are emerging as potential guardians of immune integrity.

Precision medicine, genomics and drug discovery

The hope for precision medicine has long been on the drug discovery horizon, well before the Human Genome Project gave it promise at the turn of the 21st century. In oncology, the concept has finally been realized and is now firmly embedded in ongoing drug discovery programs, and with many recent therapies involving some level of patient/disease stratification, including some highly personalized treatments. In addition, several drugs for rare diseases have been recently approved or are in late-stage clinical development, and new delivery modalities in cell and gene therapy and oligonucleotide approaches are yielding exciting new medicines for rare diseases of unmet need. For common complex diseases, however, the GWAS-driven advances in annotation of the genetic architecture over the past decade have not led to a concomitant shift in refined treatments. Similarly, attempts to disentangle treatment responders from non-responders via genetic predictors in pharmacogenetics studies have not met their anticipated success. It is possible that common diseases are simply lagging behind due to the inherent time lag with drug discovery, but it is also possible that their inherent multifactorial nature and their etiological and clinical heterogeneity will prove more resistant to refined treatment paradigms. The emergence of population-based resources in electronic health records, coupled with the rapid expansion of mobile devices and digital health may help to refine the measurement of phenotypic outcomes to match the exquisite detail emerging at the molecular level.

Regulatory circuits of T cell function in cancer

Recent progress in cancer immunotherapy emphasizes the importance of understanding immune-regulatory pathways in tumours. Dysfunction of antitumour T cells may be due to mechanisms that are evolutionarily conserved or acquired by somatic mutations. The dysfunctional state of T cells has been termed 'exhaustion', on the basis of similarities to dysfunctional T cells in chronic infections. However, despite shared properties, recent studies have identified marked differences between T cell dysfunction in cancer and chronic infection. In this Review, we discuss T cell-intrinsic molecular alterations and metabolic communication in the tumour microenvironment. Identification of the underlying molecular drivers of T cell dysfunction is essential for the continued progress of cancer research and therapy.

Assessing Immune-Related Adverse Events of Efficacious Combination Immunotherapies in Preclinical Models of Cancer

New combination immunotherapies are displaying both efficacy and immune-related adverse events (irAE) in humans. However, grade 3/4 irAEs occur in a high proportion, which can lead to discontinuation of treatment and can result in fatalities if not promptly treated. Prolonged T regulatory cell (Treg) depletion in tumor-bearing Foxp3-DTR mice using diphtheria toxin (DT) mirrored the spectrum of antitumor responses and severity of irAEs that can occur in ipilimumab/nivolumab-treated patients. In contrast, transient Treg depletion or anti-CTLA-4/PD-1 therapy had equivalent effects in mice, lowering the immune tolerance threshold and allowing irAEs to be more easily induced following treatment with additional immunomodulatory antibodies. Transient Treg depletion of DT in combination with anti-PD-1 or anti-TIM-3 monoclonal antibodies had a high therapeutic window compared with DT plus anti-CD137. In contrast, DT plus anti-CD137-treated mice developed severe irAEs similar to grade 3/4 clinical symptoms. These irAEs appeared because of an infiltration of activated proliferating effector T cells in the tissues producing IFNγ and TNF; however, TNF blockade decreased irAEs severity without impacting on tumor growth. Cancer Res; 76(18); 5288-301. ©2016 AACR.

Planes, Trains, and Automobiles: Perspectives on CAR T Cells and Other Cellular Therapies for Hematologic Malignancies

Hematologic oncologists now have at their disposal (or a referral away) a myriad of new options to get from point A (a patient with relapsed or poor-risk disease) to point B (potential tumor eradication and long-term disease-free survival). In this perspective piece, we discuss the putative mechanisms of action and the relative strengths and weaknesses of currently available cellular therapy approaches. Notably, while many of these approaches have been published in high impact journals, with the exception of allogeneic stem cell transplantation and of checkpoint inhibitors (PD1/PDL1 or CTLA4 blockade), the published clinical trials have mostly been early phase, uncontrolled studies. Therefore, many of the new cellular therapy approaches have yet to demonstrate incontrovertible evidence of enhanced overall survival compared with controls. Nonetheless, the science behind these is sure to advance our understanding of cancer immunology and ultimately to bring us closer to our goal of curing cancer.

Targeting CD73 in the tumor microenvironment with MEDI9447

MEDI9447 is a human monoclonal antibody that is specific for the ectoenzyme CD73 and currently undergoing Phase I clinical trials. Here we show that MEDI9447 is a potent inhibitor of CD73 ectonucleotidase activity, with wide ranging immune regulatory consequences. MEDI9447 results in relief from adenosine monophosphate (AMP)-mediated lymphocyte suppression in vitro and inhibition of mouse syngeneic tumor growth in vivo. In contrast with other cancer immunotherapy agents such as checkpoint inhibitors or T-cell agonists, MEDI9447 drives changes in both myeloid and lymphoid infiltrating leukocyte populations within the tumor microenvironment of mouse models. Changes include significant alterations in a number of tumor micro-environmental subpopulations including increases in CD8⁺ effector cells and activated macrophages. Furthermore, these changes correlate directly with responder and non-responder subpopulations within animal studies using syngeneic tumors. Combination data showing additive activity between MEDI9447 and anti-PD-1 antibodies using human cells in vitro and mouse tumor models further demonstrate the potential value of relieving adenosine-mediated immunosuppression. Based on these data, a Phase I study to test the safety, tolerability, and clinical activity of MEDI9447 in cancer patients was initiated (NCT02503774).

In-depth tissue profiling using multiplexed immunohistochemical consecutive staining on single slide

Despite remarkable recent achievements of immunotherapy strategies in cancer treatment, clinical responses remain limited to subsets of patients. Predictive markers of disease course and response to immunotherapy are urgently needed. Recent results have revealed the potential predictive value of immune cell phenotype and spatial distribution at the tumor site, prompting the need for multidimensional immunohistochemical analyses of tumor tissues. To address this need, we developed a sample-sparing, highly multiplexed immunohistochemistry technique based on iterative cycles of tagging, image scanning, and destaining of chromogenic substrate on a single slide. This assay, in combination with a newly developed automated digital landscaping solution, democratizes access to high-dimensional immunohistochemical analyses by capturing the complexity of the immunome using routine pathology standards. Applications of the method extend beyond cancer to screen and validate comprehensive panels of tissue-based prognostic and predictive markers, perform in-depth in situ monitoring of therapies, and identify targets of disease.

High-Resolution PET Imaging with Therapeutic Antibody-based PD-1/PD-L1 Checkpoint Tracers

Checkpoint-blocking antibodies like those targeting the PD-1/PD-L1 pathway have revolutionized oncology. We developed radiotracers based on therapeutic checkpoint-blocking antibodies permitting sensitive and high-resolution PET imaging of both PD-1 and PD-L1 in immunocompetent mice. ImmunoPET of naive mice revealed similar overall expression patterns for PD-1 and PD-L1 in secondary lymphoid organs (spleen and lymph nodes). Interestingly, PD-L1 was also detected in brown adipose tissue (BAT), confirming the notion that BAT is immunologically relevant. Under pathophysiological conditions, strong expression of the receptor/ligand pair was also found in non-lymphoid tissues. Both were specifically detected in malignant tumors. PD-1 was readily detected after combined immunoradiotherapy causing massive tumor infiltration by PD-1+ lymphocytes. PD-L1 tracer uptake was reduced in PD-L1 knockout tumors. Moreover, monitoring the expression changes of PD-L1 in response to its main inducer, the effector T cell cytokine IFN-γ, revealed robust upregulation in the lung. This suggests that T cell responses in the lung, a vital organ continuously exposed to a variety of antigens, are strongly restrained by the PD-1 checkpoint. In turn, this could explain the association of PD-1 checkpoint inhibition with potentially fatal immune-mediated pneumonitis and partially also its efficacy in lung cancer.

Checkpoint Antibodies but not T Cell-Recruiting Diabodies Effectively Synergize with TIL-Inducing γ-Irradiation

T cell-recruiting bispecific antibodies (bsAb) show promise in hematologic malignancies and are also being evaluated in solid tumors. In this study, we investigated whether T cell-recruiting bsAbs synergize with hypofractionated tumor radiotherapy (hRT) and/or blockade of the programmed death-1 (PD-1) immune checkpoint, both of which can increase tumor-infiltrating lymphocyte (TIL) numbers. Unexpectedly, large melanomas treated with hRT plus bsAb (AC133×CD3) relapsed faster than those treated with hRT alone, accompanied by massive TIL apoptosis. This fast relapse was delayed by the further addition of anti-PD-1. Mechanistic investigations revealed restimulation-induced cell death mediated by BIM and FAS as an additional cause of bsAb-mediated TIL depletion. In contrast, the double combination of hRT and anti-PD-1 strongly increased TIL numbers, and even very large tumors were completely eradicated. Our study reveals the risk that CD3-engaging bsAbs can induce apoptotic TIL depletion followed by rapid tumor regrowth, reminiscent of tolerance induction by CD3 mAb-mediated T-cell depletion, warranting caution in their use for the treatment of solid tumors. Our findings also argue that combining radiotherapy and anti-PD-1 can be quite potent, including against very large tumors. Cancer Res; 76(16); 4673-83. ©2016 AACR.

Programmed death ligand-1 expression on donor T cells drives graft-versus-host disease lethality

Programmed death ligand-1 (PD-L1) interaction with PD-1 induces T cell exhaustion and is a therapeutic target to enhance immune responses against cancer and chronic infections. In murine bone marrow transplant models, PD-L1 expression on host target tissues reduces the incidence of graft-versus-host disease (GVHD). PD-L1 is also expressed on T cells; however, it is unclear whether PD-L1 on this population influences immune function. Here, we examined the effects of PD-L1 modulation of T cell function in GVHD. In patients with severe GVHD, PD-L1 expression was increased on donor T cells. Compared with mice that received WT T cells, GVHD was reduced in animals that received T cells from Pdl1-/- donors. PD-L1-deficient T cells had reduced expression of gut homing receptors, diminished production of inflammatory cytokines, and enhanced rates of apoptosis. Moreover, multiple bioenergetic pathways, including aerobic glycolysis, oxidative phosphorylation, and fatty acid metabolism, were also reduced in T cells lacking PD-L1. Finally, the reduction of acute GVHD lethality in mice that received Pdl1-/- donor cells did not affect graft-versus-leukemia responses. These data demonstrate that PD-L1 selectively enhances T cell-mediated immune responses, suggesting a context-dependent function of the PD-1/PD-L1 axis, and suggest selective inhibition of PD-L1 on donor T cells as a potential strategy to prevent or ameliorate GVHD.

Clinical impact of tumour biology in the management of gastroesophageal cancer

The characterization of oesophageal and gastric cancer into subtypes based on genotype has evolved in the past decade. Insights into the molecular landscapes of gastroesophageal cancer provide a roadmap to assist the development of new drugs and their use in combinations, for patient stratification, and for trials of targeted therapies. Trastuzumab is the only approved treatment for gastroesophageal cancers that overexpress HER2. Acquired resistance usually limits the duration of response to this treatment, although a number of new agents directed against HER2 have the potential to overcome or prolong the time until resistance occurs. Beyond that, anti-VEGFR2 therapy with ramucirumab was the first biological treatment strategy to produce a survival benefit in an unselected population of patients with chemotherapy-refractory gastroesophageal cancer. Large initiatives are starting to address the role of biomarker-driven targeted therapy in the metastatic and in the perioperative setting for patients with this disease. Immunotherapy also holds promise, and our understanding of subsets of gastroesophageal cancer based on patterns of immune response continues to evolve. Efforts are underway to identify more relevant genomic subsets through genomic screening, functional studies, and molecular characterization. Herein, we provide an overview of the key developments in the treatment of gastroesophageal cancer, and discuss potential strategies to further optimize therapy by targeting disease subtypes.

Genetically Engineered Mouse Models of Pancreatic Cancer: The KPC Model (LSL-Kras(G12D/+) ;LSL-Trp53(R172H/+) ;Pdx-1-Cre), Its Variants, and Their Application in Immuno-oncology Drug Discovery

Pancreatic ductal adenocarcinoma (PDAC) ranks fourth among cancer-related deaths in the United States. For patients with unresectable disease, treatment options are limited and lack curative potential. Preclinical mouse models of PDAC that recapitulate the biology of human pancreatic cancer offer an opportunity for the rational development of novel treatment approaches that may improve patient outcomes. With the recent success of immunotherapy for subsets of patients with solid malignancies, interest is mounting in the possible use of immunotherapy for the treatment of PDAC. Considered in this unit is the value of genetic mouse models for characterizing the immunobiology of PDAC and for investigating novel immunotherapeutics. Several variants of these models are described, all of which may be used in drug development and for providing information on unique aspects of disease biology and therapeutic responsiveness. © 2016 by John Wiley & Sons, Inc.