Defining the critical hurdles in cancer immunotherapy

Advancing cancer drug development with mechanistic mathematical modeling: bridging the gap between theory and practice

Quantitative predictive modeling of cancer growth, progression, and individual response to therapy is a rapidly growing field. Researchers from mathematical modeling, systems biology, pharmaceutical industry, and regulatory bodies, are collaboratively working on predictive models that could be applied for drug development and, ultimately, the clinical management of cancer patients. A plethora of modeling paradigms and approaches have emerged, making it challenging to compile a comprehensive review across all subdisciplines. It is therefore critical to gauge fundamental design aspects against requirements, and weigh opportunities and limitations of the different model types. In this review, we discuss three fundamental types of cancer models: space-structured models, ecological models, and immune system focused models. For each type, it is our goal to illustrate which mechanisms contribute to variability and heterogeneity in cancer growth and response, so that the appropriate architecture and complexity of a new model becomes clearer. We present the main features addressed by each of the three exemplary modeling types through a subjective collection of literature and illustrative exercises to facilitate inspiration and exchange, with a focus on providing a didactic rather than exhaustive overview. We close by imagining a future multi-scale model design to impact critical decisions in oncology drug development.

Challenges and opportunities in cancer immunotherapy: a Society for Immunotherapy of Cancer (SITC) strategic vision

Cancer immunotherapy has flourished over the last 10-15 years, transforming the practice of oncology and providing long-term clinical benefit to some patients. During this time, three distinct classes of immune checkpoint inhibitors, chimeric antigen receptor-T cell therapies specific for two targets, and two distinct classes of bispecific T cell engagers, a vaccine, and an oncolytic virus have joined cytokines as a standard of cancer care. At the same time, scientific progress has delivered vast amounts of new knowledge. For example, advances in technologies such as single-cell sequencing and spatial transcriptomics have provided deep insights into the immunobiology of the tumor microenvironment. With this rapid clinical and scientific progress, the field of cancer immunotherapy is currently at a critical inflection point, with potential for exponential growth over the next decade. Recognizing this, the Society for Immunotherapy of Cancer convened a diverse group of experts in cancer immunotherapy representing academia, the pharmaceutical and biotechnology industries, patient advocacy, and the regulatory community to identify current opportunities and challenges with the goal of prioritizing areas with the highest potential for clinical impact. The consensus group identified seven high-priority areas of current opportunity for the field: mechanisms of antitumor activity and toxicity; mechanisms of drug resistance; biomarkers and biospecimens; unique aspects of novel therapeutics; host and environmental interactions; premalignant immunity, immune interception, and immunoprevention; and clinical trial design, endpoints, and conduct. Additionally, potential roadblocks to progress were discussed, and several topics were identified as cross-cutting tools for optimization, each with potential to impact multiple scientific priority areas. These cross-cutting tools include preclinical models, data curation and sharing, biopsies and biospecimens, diversification of funding sources, definitions and standards, and patient engagement. Finally, three key guiding principles were identified that will both optimize and maximize progress in the field. These include engaging the patient community; cultivating diversity, equity, inclusion, and accessibility; and leveraging the power of artificial intelligence to accelerate progress. Here, we present the outcomes of these discussions as a strategic vision to galvanize the field for the next decade of exponential progress in cancer immunotherapy.

Flow Cytometry - Sophisticated Tool for Basic Research or/and Routine Diagnosis; Impact of the Complementarity in Both Pre- as Well as Clinical Studies

Flow cytometry is a sophisticated technology used widely in both basic research and as a routine tool in clinical diagnosis. The technology has progressed from single parameter detection in the 1970s and 1980s to high end multicolor analysis, with currently 30 parameters detected simultaneously, allowing the identification and purification of rare subpopulations of cells of interest. Flow cytometry continues to evolve and expand to facilitate the investigation of new diagnostic and therapeutic avenues. The present review gives an overview of basic theory and instrumentation, presents and compares the advantages and disadvantages of conventional, spectral and imaging flow cytometry as well as mass cytometry. Current methodologies and applications in both research, pre- and clinical settings are discussed, as well as potential limitations and future evolution. This finding encourages the reader to promote such relationship between basic science, diagnosis and multidisciplinary approach since the standard methods have limitations (e.g., in differentiating the cells after staining). Moreover, such path inspires future cytometry specialists develop new/alternative frontiers between pre- and clinical diagnosis and be more flexible in designing the study for both human as well as veterinary medicine.

Expression of programmed cell death-1 on neuroblastoma cells in TH-MYCN transgenic mice

BACKGROUND

Immunotherapy may improve the poor prognosis of high-risk neuroblastoma. Programmed cell death-1 (PD-1) is expressed in several cancers. The tyrosine hydroxylase MYCN (TH-MYCN) transgenic mouse model is widely used in neuroblastoma research, but detailed information on its immunological background is lacking. Therefore, we studied the immunological tumor microenvironment and tumor cell surface antigen expression in homozygote and hemizygote mice and effects of antibody therapy against PD-1.

METHODS

CD4, CD8, CD11b, and CD11c expression in immune cells from retroperitoneal lymph nodes and spleen was analyzed by flow cytometry. Tumor cell surface antigen expression was confirmed, and data from homozygote and hemizygote mice were compared. Effects of anti-PD-1 antibody were evaluated.

RESULTS

CD4-, CD8-, CD11b-, and CD11c-positive cells were not significantly different in homozygote and hemizygote mice, and CD11b- and CD11c-positive cells were identified in the tumor microenvironment in both. Tumor cells expressed PD-1, and anti-PD-1 antibody had anti-tumor effects and significantly reduced the percentage of living tumor cells in cultures after 2 h.

CONCLUSION

The immunological background is similar in homozygote and hemizygote TH-MYCN transgenic mice, and both have PD-1-positive tumor cells. Anti-PD-1 antibody suppresses tumor growth. This mouse model may be a useful for studying immunotherapy of neuroblastoma.

Early cancer cachexia phenotype predicts survival of advanced urothelial cancer patients treated with pembrolizumab

AIM

We aimed to explore the association between cancer cachexia phenotypes in the early phase of treatment induction and the prognosis of advanced urothelial cancer (aUC) patients receiving pembrolizumab.

METHODS

This retrospective study included 31 aUC patients treated with pembrolizumab as a second- or later-line therapy. Patients were categorized into three early cancer cachexia phenotypes by changes in skeletal muscle and total adipose indices calculated using computed tomography images taken immediately before and within 3 months after the initiation of pembrolizumab: No Wasting (NW, 11 patients), Fat-Only Wasting (FW, 13), and Muscle and Fat Wasting (MFW, seven). Its association with objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) were evaluated.

RESULTS

The median follow-up period was 5.7 months. The median number of cycles of pembrolizumab was five. The ORR in NW/FW/MFW was 86%/38%/0%, respectively (p = 0.001). The PFS and OS rates were the best in NW, followed in order by FW and MFW (PFS, 69%/45%/0% at 12 months, p = 0.008; OS, 100%/65%/0% at 12 months, p < 0.001). In multivariate analysis including posttherapeutic cachexia-associated parameters, cancer cachexia phenotype (MFW vs. FW/NW) was an independent predictor of poor OS (hazard ratio 8.59, p < 0.001) along with an increase in neutrophil-lymphocyte ratio (p = 0.028).

CONCLUSION

Early cancer cachexia phenotypes were significantly associated with the survival of aUC patients treated with pembrolizumab. In contrast to the very early progression and poor prognosis in the MFW group, long-term survival can be expected in the NW/FW groups.

Immune checkpoint inhibitors for triple-negative breast cancer: From immunological mechanisms to clinical evidence

Breast cancer is the most common cancer type in women worldwide. Triple-negative breast cancer (TNBC), which is characterized by the absence of estrogen receptor/progesterone receptor (ER/PR) and human epidermal growth factor receptor 2 (Her2) expressions, has a poorer prognosis compared with non-TNBC breast tumors. Until recently systemic treatment for TNBC was confined to chemotherapy owing to the lack of actionable targets. Immune checkpoint molecules are expressed on malignant cells or tumor-infiltrating immune cells and can inhibit anti-cancer immune responses. Immune checkpoint inhibitors (ICI), including anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), anti-programmed cell death protein 1 (PD-1), and anti-programmed cell death 1 ligand 1 (PD-L1), induce immune responses in different types of neoplasms. They have recently gained attention for their possible role in TNBC treatment. Several clinical trials have been conducted on the role of immune checkpoint blockade in different settings for TNBC treatment. Available evidence justifies the application of ICI and chemotherapy combination in the management of metastatic TNBC and early-stage TNBC in neoadjuvant setting. This study aims to provide information on the mechanisms of action of ICIs, review the efficacy results of clinical trials using ICIs for TNBC treatment, and assess the side effects of such drugs.

PDCD1 Polymorphisms May Predict Response to Anti-PD-1 Blockade in Patients With Metastatic Melanoma

A significant number of patients (pts) with metastatic melanoma do not respond to anti-programmed cell death 1 (PD1) therapies. Identifying predictive biomarkers therefore remains an urgent need. We retrospectively analyzed plasma DNA of pts with advanced melanoma treated with PD-1 antibodies, nivolumab or pembrolizumab, for five PD-1 genotype single nucleotide polymorphisms (SNPs): PD1.1 (rs36084323, G>A), PD1.3 (rs11568821, G>A), PD1.5 (rs2227981, C>T) PD1.6 (rs10204225, G>A) and PD1.9 (rs2227982, C>T). Clinico-pathological and treatment parameters were collected, and presence of SNPs correlated with response, progression free survival (PFS) and overall survival (OS). 115 patients were identified with a median follow up of 18.7 months (range 0.26 – 52.0 months). All were Caucasian; 27% BRAF V600 mutation positive. At PD-1 antibody commencement, 36% were treatment-naïve and 52% had prior ipilimumab. The overall response rate was 43%, 19% achieving a complete response. Overall median PFS was 11.0 months (95% CI 5.4 - 17.3) and median OS was 31.1 months (95% CI 23.2 - NA). Patients with the G/G genotype had more complete responses than with A/G genotype (16.5% vs. 2.6% respectively) and the G allele of PD1.3 rs11568821 was significantly associated with a longer median PFS than the AG allele, 14.1 vs. 7.0 months compared to the A allele (p=0.04; 95% CI 0.14 – 0.94). No significant association between the remaining SNPs and responses, PFS or OS were observed. Despite limitations in sample size, this is the first study to demonstrate an association of a germline PD-1 polymorphism and PFS in response to anti-PD-1 therapy in pts with metastatic melanoma. Extrinsic factors like host germline polymorphisms should be considered with tumor intrinsic factors as predictive biomarkers for immune checkpoint regulators.

Nomogram based on immune scores for predicting the survival of patients with esophageal squamous cell carcinoma

Objective

To explore the relationship between immune scores and prognosis of patients with esophageal squamous cell carcinoma (ESCC) and construct a corresponding clinical prediction model.

Methods

The present research was a retrospective cohort study. We obtained the clinical information and immune scores of 137 patients with ESCC from The Cancer Genome Atlas database, and a Cox proportional risk model was used to construct the clinical prediction model. The concordance index, receiver operating characteristic curve, calibration curve, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were used to evaluate model performance and prediction accuracy.

Results

Patients with a high immune score (> −121.4) showed a worse prognosis than those with a low immune score (< −645.8; hazard ratio=3.743, 95% confidence interval [CI]=1.385–10.115, P=0.009). The concordance index of the predictive model was 0.733 (95% CI=0.655–0.812). The calibration curve showed that the 3- and 5-year overall survival rates predicted by the model were highly consistent with the observed values. The NRI and IDI for the 3-year overall survival indicated that the model with the immune scores was superior for classifying the risk probability and distinguishing cases.

Conclusion

Immune scores may be an independent predictor of prognosis in patients with ESCC.

Full Spectrum Flow Cytometry as a Powerful Technology for Cancer Immunotherapy Research

The Nobel Prize-deserving concept of blocking inhibitory pathways in T cells, to unleash their anti-tumoral capacity, became one of the pillars of cancer treatment in the last decade and has resulted in durable clinical responses for multiple cancer types. Currently, two of the most important goals in cancer immunotherapy are to understand the mechanisms resulting in failure to checkpoint blockade and to identify predictive immunological biomarkers that correlate to treatment response, disease progression or adverse effects. The identification and validation of biomarkers for routine clinical use is not only critical to monitor disease or treatment progression, but also to personalize and develop new therapies. To achieve these goals, powerful research tools are needed. Flow cytometry stands as one of the most successful single-cell analytical tools used to characterize immune cell phenotypes to monitor solid tumors, hematological malignancies, minimal residual disease or metastatic progression. This technology has been fundamental in diagnosis, treatment and translational research in cancer clinical trials. Most recently, the need to evaluate simultaneously more features in each cell has pushed the field to implement more powerful adaptations beyond conventional flow cytometry, including Full Spectrum Flow Cytometry (FSFC). FSFC captures the full emission spectrum of fluorescent molecules using arrays of highly sensitive light detectors, and to date has enabled characterization of 40 parameters in a single sample. We will summarize the contributions of this technology to the advancement of research in immunotherapy studies and discuss best practices to obtain reliable, robust and reproducible FSFC results.

Bi- and Tri-Specific T Cell Engager-Armed Oncolytic Viruses: Next-Generation Cancer Immunotherapy

Oncolytic viruses (OVs) are potent anti-cancer biologics with a bright future, having substantial evidence of efficacy in patients with cancer. Bi- and tri-specific antibodies targeting tumor antigens and capable of activating T cell receptor signaling have also shown great promise in cancer immunotherapy. In a cutting-edge strategy, investigators have incorporated the two independent anti-cancer modalities, transforming them into bi- or tri-specific T cell engager (BiTE or TriTE)-armed OVs for targeted immunotherapy. Since 2014, multiple research teams have studied this combinatorial strategy, and it showed substantial efficacy in various tumor models. Here, we first provide a brief overview of the current status of oncolytic virotherapy and the use of multi-specific antibodies for cancer immunotherapy. We then summarize progress on BiTE and TriTE antibodies as a novel class of cancer therapeutics in preclinical and clinical studies, followed by a discussion of BiTE- or TriTE-armed OVs for cancer therapy in translational models. In addition, T cell receptor mimics (TCRm) have been developed into BiTEs and are expected to greatly expand the application of BiTEs and BiTE-armed OVs for the effective targeting of intracellular tumor antigens. Future applications of such innovative combination strategies are emerging as precision cancer immunotherapies.

Repurposing Food and Drug Administration-Approved Drugs to Promote Antitumor Immunity

There has been a major resurgence of interest in immune-based approaches to treat cancer, based largely on the success of checkpoint inhibitors (anti-cytotoxic T-lymphocyte-associated antigen 4, anti-programmed cell death 1, and anti-programmed cell death ligand 1 antibodies) in several malignancies. However, not all tumors respond to checkpoint therapy, and there is clearly a need for additional approaches for enhancing tumor immunity. We summarize the critical elements necessary for mounting an efficacious T-cell response to a tumor. We cite drugs approved by the Food and Drug Administration for no-cancer indications that could be repurposed and used as part of an antitumor immune cocktail. We also list cancer drugs not initially intended to impact tumor immunity (soft repurposing) but that have been found to modulate the immune system. We highlight those drugs that might be used in combination with checkpoint inhibitors to increase response rates and survival of cancer patients. Our focus will be on drugs for which there are limited but existing human data. We cite supporting mechanistic mouse data as well. Repurposing drugs to modulate antitumor immunity is an opportunity to rapidly bring new, effective, and affordable treatments to cancer patients.

Deregulation of Adaptive T Cell Immunity in Multiple Myeloma: Insights Into Mechanisms and Therapeutic Opportunities

Immunotherapy has recently emerged as a promising treatment option for multiple myeloma (MM) patients. Profound immune dysfunction and evasion of immune surveillance are known to characterize MM evolution and disease progression. Along with genomic changes observed in malignant plasma cells, the bone marrow (BM) milieu creates a protective environment sustained by the complex interaction of BM stromal cells (BMSCs) and malignant cells that using bidirectional connections and cytokines released stimulate disease progression, drug resistance and enable immune escape. Local immune suppression and T-cell exhaustion are important mediating factors of clinical outcomes and responses to immune-based approaches. Thus, further characterization of the defects present in the immune system of MM patients is essential to develop novel therapies and to repurpose the existing ones. This review seeks to provide insights into the mechanisms that promote tumor escape, cause inadequate T-cell stimulation and impaired cytotoxicity in MM. Furthermore, it highlights current immunotherapies being used to restore adaptive T-cell immune responses in MM and describes strategies created to escape these multiple immune evasion mechanisms.

RNA-loaded dendritic cells: more than a tour de force in cancer therapeutics

A wide array of therapeutic strategies has been implemented against cancers, yet their clinical benefit is limited. The lack of clinical efficacy of the conventional treatment options might be due to the inept immune competency of the patients. Dendritic cells (DCs) have a vital role in initiating and directing immune responses and have been frequently used as delivery vehicles in clinical research. The recent clinical data suggest the potential use of DCs pulsed with nucleic acid, especially with RNA holds a great potential as an immunotherapeutic measure with compare to other cancer therapeutics. This review mainly deals with the DCs and their role in transfection with RNA in cancer immunotherapy.

Quantitative Systems Pharmacology: An Exemplar Model-Building Workflow With Applications in Cardiovascular, Metabolic, and Oncology Drug Development

Quantitative systems pharmacology (QSP), a mechanistically oriented form of drug and disease modeling, seeks to address a diverse set of problems in the discovery and development of therapies. These problems bring a considerable amount of variability and uncertainty inherent in the nonclinical and clinical data. Likewise, the available modeling techniques and related software tools are manifold. Appropriately, the development, qualification, application, and impact of QSP models have been similarly varied. In this review, we describe the progressive maturation of a QSP modeling workflow: a necessary step for the efficient, reproducible development and qualification of QSP models, which themselves are highly iterative and evolutive. Furthermore, we describe three applications of QSP to impact drug development; one supporting new indications for an approved antidiabetic clinical asset through mechanistic hypothesis generation, one highlighting efficacy and safety differentiation within the sodium‐glucose cotransporter‐2 inhibitor drug class, and one enabling rational selection of immuno‐oncology drug combinations.

Quantitative Mechanistic Modeling in Support of Pharmacological Therapeutics Development in Immuno-Oncology

Following the approval, in recent years, of the first immune checkpoint inhibitor, there has been an explosion in the development of immuno-modulating pharmacological modalities for the treatment of various cancers. From the discovery phase to late-stage clinical testing and regulatory approval, challenges in the development of immuno-oncology (IO) drugs are multi-fold and complex. In the preclinical setting, the multiplicity of potential drug targets around immune checkpoints, the growing list of immuno-modulatory molecular and cellular forces in the tumor microenvironment-with additional opportunities for IO drug targets, the emergence of exploratory biomarkers, and the unleashed potential of modality combinations all have necessitated the development of quantitative, mechanistically-oriented systems models which incorporate key biology and patho-physiology aspects of immuno-oncology and the pharmacokinetics of IO-modulating agents. In the clinical setting, the qualification of surrogate biomarkers predictive of IO treatment efficacy or outcome, and the corresponding optimization of IO trial design have become major challenges. This mini-review focuses on the evolution and state-of-the-art of quantitative systems models describing the tumor vs. immune system interplay, and their merging with quantitative pharmacology models of IO-modulating agents, as companion tools to support the addressing of these challenges.

Tumor-Associated Disialylated Glycosphingolipid Antigen-Revealing Antibodies Found in Melanoma Patients' Immunoglobulin Repertoire Suggest a Two-Direction Regulation Mechanism Between Immune B Cells and the Tumor

There is far less information available about the tumor infiltrating B (TIL-B) cells, than about the tumor infiltrating T cells. We focused on discovering the features and potential role of B lymphocytes in solid tumors. Our project aimed to develop innovative strategies to define cancer membrane structures. We chose two solid tumor types, with variable to considerable B cell infiltration. The strategy we set up with invasive breast carcinoma, showing medullary features, has been introduced and standardized in metastatic melanoma. After detecting B lymphocytes by immunohistochemistry, VH-JH, Vκ-Jκ immunoglobulin rearranged V region genes were amplified by RT-PCR, from TIL-B cDNA. Immunoglobulin variable-region genes of interest were cloned, sequenced, and subjected to a comparative DNA analysis. Single-chain variable (scFv) antibody construction was performed in selected cases to generate a scFv library and to test tumor binding capacity. DNA sequence analysis revealed an overrepresented VH3-1 cluster, represented both in the breast cancer and the melanoma TIL-B immunoglobulin repertoire. We observed that our previously defined anti GD3 ganglioside-binder antibody-variable region genes were present in melanoma as well. Our antibody fragments showed binding potential to disialylated glycosphingolipids (GD3 ganglioside) and their O acetylated forms on melanoma cancer cells. We conclude that our results have a considerable tumor immunological impact, as they reveal the power of TIL-B cells to recognize strong tumor-associated glycosphingolipid structures on melanomas and other solid tumors. As tumor-derived gangliosides affect immune cell functions and reduce the B lymphocytes' antibody production, we suspect an important B lymphocyte and cancer cell crosstalk mechanism. We not only described the isolation and specificity testing of the tumor infiltrating B cells, but also showed the TIL-B cells' highly tumor-associated GD3 ganglioside-revealing potential in melanomas. The present data help to identify new cancer-associated biomarkers that may serve for novel cancer diagnostics. The two-direction regulation mechanism between immune B cells and the tumor could eventually be developed into an innovative cancer treatment strategy.

Precision immunoprofiling by image analysis and artificial intelligence

Clinical success of immunotherapy is driving the need for new prognostic and predictive assays to inform patient selection and stratification. This requirement can be met by a combination of computational pathology and artificial intelligence. Here, we critically assess computational approaches supporting the development of a standardized methodology in the assessment of immune-oncology biomarkers, such as PD-L1 and immune cell infiltrates. We examine immunoprofiling through spatial analysis of tumor-immune cell interactions and multiplexing technologies as a predictor of patient response to cancer treatment. Further, we discuss how integrated bioinformatics can enable the amalgamation of complex morphological phenotypes with the multiomics datasets that drive precision medicine. We provide an outline to machine learning (ML) and artificial intelligence tools and illustrate fields of application in immune-oncology, such as pattern-recognition in large and complex datasets and deep learning approaches for survival analysis. Synergies of surgical pathology and computational analyses are expected to improve patient stratification in immuno-oncology. We propose that future clinical demands will be best met by (1) dedicated research at the interface of pathology and bioinformatics, supported by professional societies, and (2) the integration of data sciences and digital image analysis in the professional education of pathologists.

An approved in vitro approach to preclinical safety and efficacy evaluation of engineered T cell receptor anti-CD3 bispecific (ImmTAC) molecules

Robust preclinical testing is essential to predict clinical safety and efficacy and provide data to determine safe dose for first-in-man studies. There are a growing number of examples where the preclinical development of drugs failed to adequately predict clinical adverse events in part due to their assessment with inappropriate preclinical models. Preclinical investigations of T cell receptor (TCR)-based immunotherapies prove particularly challenging as these biologics are human-specific and thus the conventional testing in animal models is inadequate. As these molecules harness the full force of the immune system, and demonstrate tremendous potency, we set out to design a preclinical package that would ensure adequate evaluation of these therapeutics. Immune Mobilising Monoclonal TCR Against Cancer (ImmTAC) molecules are bi-specific biologics formed of an affinity-enhanced TCR fused to an anti-CD3 effector function. ImmTAC molecules are designed to activate human T lymphocytes and target peptides within the context of a human leukocyte antigen (HLA), thus require an intact human immune system and peptidome for suitable preclinical screening. Here we draw upon the preclinical testing of four ImmTAC molecules, including IMCgp100, the first ImmTAC molecule to reach the clinic, to present our comprehensive, informative and robust approach to in vitro preclinical efficacy and safety screening. This package comprises a broad range of cellular and molecular assays using human tissues and cultured cells to test efficacy, safety and specificity, and hence predict human responses in clinical trials. We propose that this entirely in vitro package offers a potential model to be applied to screening other TCR-based biologics.

Digital image analysis improves precision of PD-L1 scoring in cutaneous melanoma

AIMS

Immune checkpoint inhibitors have become a successful treatment in metastatic melanoma. The high response rates in a subset of patients suggest that a sensitive companion diagnostic test is required. The predictive value of programmed death ligand 1 (PD-L1) staining in melanoma has been questioned due to inconsistent correlation with clinical outcome. Whether this is due to predictive irrelevance of PD-L1 expression or inaccurate assessment techniques remains unclear. The aim of this study was to develop a standardised digital protocol for the assessment of PD-L1 staining in melanoma and to compare the output data and reproducibility to conventional assessment by expert pathologists.

METHODS AND RESULTS

In two cohorts with a total of 69 cutaneous melanomas, a highly significant correlation was found between pathologist-based consensus reading and automated PD-L1 analysis (r = 0.97, P < 0.0001). Digital scoring captured the full diagnostic spectrum of PD-L1 expression at single cell resolution. An average of 150 472 melanoma cells (median 38 668 cells; range = 733-1 078 965) were scored per lesion. Machine learning was used to control for heterogeneity introduced by PD-L1-positive inflammatory cells in the tumour microenvironment. The PD-L1 image analysis protocol showed excellent reproducibility (r = 1.0, P < 0.0001) when carried out on independent workstations and reduced variability in PD-L1 scoring of human observers. When melanomas were grouped by PD-L1 expression status, we found a clear correlation of PD-L1 positivity with CD8-positive T cell infiltration, but not with tumour stage, metastasis or driver mutation status.

CONCLUSION

Digital evaluation of PD-L1 reduces scoring variability and may facilitate patient stratification in clinical practice.

A novel allogeneic off-the-shelf dendritic cell vaccine for post-remission treatment of elderly patients with acute myeloid leukemia

In elderly acute myeloid leukemia (AML) patients post-remission treatment options are associated with high comorbidity rates and poor survival. Dendritic cell (DC)-based immunotherapy is a promising alternative treatment strategy. A novel allogeneic DC vaccine, DCP-001, was developed from an AML-derived cell line that uniquely combines the positive features of allogeneic DC vaccines and expression of multi-leukemia-associated antigens. Here, we present data from a phase I study conducted with DCP-001 in 12 advanced-stage elderly AML patients. Patients enrolled were in complete remission (CR1/CR2) (n = 5) or had smoldering disease (n = 7). All patients were at high risk of relapse and ineligible for post-remission intensification therapies. A standard 3 + 3 dose escalation design with extension to six patients in the highest dose was performed. Patients received four biweekly intradermal DCP-001 injections at different dose levels (10, 25, and 50 million cells DCP-001) and were monitored for clinical and immunological responses. Primary objectives of the study (feasibility and safety) were achieved with 10/12 patients completing the vaccination program. Treatment was well tolerated. A clear-cut distinction between patients with and without detectable circulating leukemic blasts during the vaccination period was noted. Patients with no circulating blasts showed an unusually prolonged survival [median overall survival 36 months (range 7–63) from the start of vaccination] whereas patients with circulating blasts, died within 6 months. Long-term survival was correlated with maintained T cell levels and induction of multi-functional immune responses. It is concluded that DCP-001 in elderly AML patients is safe, feasible and generates both cellular and humoral immune responses.

Bags versus flasks: a comparison of cell culture systems for the production of dendritic cell-based immunotherapies

In recent years, cell-based therapies targeting the immune system have emerged as promising strategies for cancer treatment. This review summarizes manufacturing challenges related to production of antigen presenting cells as a patient-tailored cancer therapy. Understanding cell-material interactions is essential because in vitro cell culture manipulations to obtain mature antigen-producing cells can significantly alter their in vivo performance. Traditional antigen-producing cell culture protocols often rely on cell adhesion to surface-treated hydrophilic polystyrene flasks. More recent commercial and investigational cancer immunotherapy products were manufactured using suspension cell culture in closed hydrophobic fluoropolymer bags. The shift to closed cell culture systems can decrease risks of contamination by individual operators, as well as facilitate scale-up and automation. Selecting closed cell culture bags over traditional open culture systems entails different handling procedures and processing controls, which can affect product quality. Changes in culture vessels also entail changes in vessel materials and geometry, which may alter the cell microenvironment and resulting cell fate decisions. Strategically designed culture systems will pave the way for the generation of more sophisticated and highly potent cell-based cancer vaccines. As an increasing number of cell-based therapies enter the clinic, the selection of appropriate cell culture vessels and materials becomes a critical consideration that can impact the therapeutic efficacy of the product, and hence clinical outcomes and patient quality of life.

Cancer vaccines: translation from mice to human clinical trials

Therapeutic cancer vaccines have been a long-sought approach to harness the exquisite specificity of the immune system to treat cancer, but until recently have not had much success as single agents in clinical trials. However, new understanding of the immunoregulatory mechanisms exploited by cancers has allowed the development of approaches to potentiate the effect of vaccines by removing the brakes while the vaccines step on the accelerator. Thus, vaccines that had induced a strong T cell response but no clinical therapeutic effect may now reach their full potential. Here, we review a number of promising approaches to cancer vaccines developed initially in mouse models and their translation into clinical trials, along with combinations of vaccines with other therapies that might allow cancer vaccines to finally achieve clinical efficacy against many types of cancer.

Harnessing the immune system in the battle against breast cancer

Breast cancer is the most prevalent malignancy in women and the second most common cause of cancer-related death worldwide. Despite major innovations in early detection and advanced therapeutics, up to 30% of women with node-negative breast cancer and 70% of women with node-positive breast cancer will develop recurrence. The recognition that breast tumors are infiltrated by a complex array of immune cells that influence their development, progression, and metastasis, as well as their responsiveness to systemic therapies has sparked major interest in the development of immunotherapies. In fact, not only the native host immune system can be altered to promote potent antitumor response, but also its components can be manipulated to generate effective therapeutic strategies. We present here a review of the major approaches to immunotherapy in breast cancers, both successes and failures, as well as new therapies on the horizon.

Promoting the accumulation of tumor-specific T cells in tumor tissues by dendritic cell vaccines and chemokine-modulating agents

This protocol describes how to induce large numbers of tumor-specific cytotoxic T cells (CTLs) in the spleens and lymph nodes of mice receiving dendritic cell (DC) vaccines and how to modulate tumor microenvironments (TMEs) to ensure effective homing of the vaccination-induced CTLs to tumor tissues. We also describe how to evaluate the numbers of tumor-specific CTLs within tumors. The protocol contains detailed information describing how to generate a specialized DC vaccine with augmented ability to induce tumor-specific CTLs. We also describe methods to modulate the production of chemokines in the TME and show how to quantify tumor-specific CTLs in the lymphoid organs and tumor tissues of mice receiving different treatments. The combined experimental procedure, including tumor implantation, DC vaccine generation, chemokine-modulating (CKM) approaches, and the analyses of tumor-specific systemic and intratumoral immunity is performed over 30-40 d. The presented ELISpot-based ex vivo CTL assay takes 6 h to set up and 5 h to develop. In contrast to other methods of evaluating tumor-specific immunity in tumor tissues, our approach allows detection of intratumoral T-cell responses to nonmanipulated weakly immunogenic cancers. This detection method can be performed using basic laboratory skills, and facilitates the development and preclinical evaluation of new immunotherapies.

Cancer vaccine strategies: translation from mice to human clinical trials

We translated two cancer vaccine strategies from mice into human clinical trials. (1) In preclinical studies on TARP, an antigen expressed in most prostate cancers, we mapped epitopes presented by HLA-A*0201, modified them to increase affinity and immunogenicity in HLA transgenic mice, and induced human T cells that killed human cancer cells ("epitope enhancement"). In a clinical trial, HLA-A2⁺ prostate cancer patients with PSA biochemical recurrence (Stage D0) were vaccinated with two peptides either in Montanide-ISA51 or on autologous dendritic cells (DCs). In stage D0, the Prostate-Specific Antigen (PSA) slope is prognostic of time to radiographic evidence of metastases and death. With no difference between arms, 74% of combined subjects had a decreased PSA slope at 1 year compared to their own baseline slopes (p = 0.0004). For patients vaccinated with DCs, response inversely correlated with a tolerogenic DC signature. A randomized placebo-controlled phase II trial is underway. (2) HER2 is a driver surface oncogene product expressed in multiple tumors. We made an adenoviral vector vaccine expressing the extracellular and transmembrane domains of HER2 and cured mice with large established HER2⁺ tumors, dependent on antibodies to HER2, not T cells. The mechanism differed from that of trastuzumab. We tested a human version in advanced metastatic cancer patients naïve to HER2-directed therapies. At the second and third dose levels, 45% of evaluable patients showed clinical benefit. Circulating tumor cells also declined in some vaccinated patients. Thus, cancer vaccines developed in mice were successfully translated to humans with promising early results.

Immuno-Oncology-The Translational Runway for Gene Therapy: Gene Therapeutics to Address Multiple Immune Targets

Cancer therapy is once again experiencing a paradigm shift. This shift is based on extensive clinical experience demonstrating that cancer cannot be successfully fought by addressing only single targets or pathways. Even the combination of several neo-antigens in cancer vaccines is not sufficient for successful, lasting tumor eradication. The focus has therefore shifted to the immune system's role in cancer and the striking abilities of cancer cells to manipulate and/or deactivate the immune system. Researchers and pharma companies have started to target the processes and cells known to support immune surveillance and the elimination of tumor cells. Immune processes, however, require novel concepts beyond the traditional "single-target-single drug" paradigm and need parallel targeting of diverse cells and mechanisms. This review gives a perspective on the role of gene therapy technologies in the evolving immuno-oncology space and identifies gene therapy as a major driver in the development and regulation of effective cancer immunotherapy. Present challenges and breakthroughs ranging from chimeric antigen receptor T-cell therapy, gene-modified oncolytic viruses, combination cancer vaccines, to RNA therapeutics are spotlighted. Gene therapy is recognized as the most prominent technology enabling effective immuno-oncology strategies.

The Society for Immunotherapy of Cancer Biomarkers Task Force recommendations review

The clinical successes in cancer immunotherapy have led to a critical need for biomarkers in cancer immunotherapy. It is of the utmost importance to know who is most likely to benefit from these therapies (predictive biomarkers) but also who is starting to respond (prognostic biomarkers) and how the therapy functions in order to make rational combination choices (mechanism of action biomarkers). The Society for Immunotherapy of Cancer (SITC) Biomarkers Task Force addressed the state of the art and made a series of recommendations for the field, which is summarized here.

The Oncopig Cancer Model: An Innovative Large Animal Translational Oncology Platform

Despite an improved understanding of cancer molecular biology, immune landscapes, and advancements in cytotoxic, biologic, and immunologic anti-cancer therapeutics, cancer remains a leading cause of death worldwide. More than 8.2 million deaths were attributed to cancer in 2012, and it is anticipated that cancer incidence will continue to rise, with 19.3 million cases expected by 2025. The development and investigation of new diagnostic modalities and innovative therapeutic tools is critical for reducing the global cancer burden. Toward this end, transitional animal models serve a crucial role in bridging the gap between fundamental diagnostic and therapeutic discoveries and human clinical trials. Such animal models offer insights into all aspects of the basic science-clinical translational cancer research continuum (screening, detection, oncogenesis, tumor biology, immunogenicity, therapeutics, and outcomes). To date, however, cancer research progress has been markedly hampered by lack of a genotypically, anatomically, and physiologically relevant large animal model. Without progressive cancer models, discoveries are hindered and cures are improbable. Herein, we describe a transgenic porcine model—the Oncopig Cancer Model (OCM)—as a next-generation large animal platform for the study of hematologic and solid tumor oncology. With mutations in key tumor suppressor and oncogenes, TP53^R167H and KRAS^G12D, the OCM recapitulates transcriptional hallmarks of human disease while also exhibiting clinically relevant histologic and genotypic tumor phenotypes. Moreover, as obesity rates increase across the global population, cancer patients commonly present clinically with multiple comorbid conditions. Due to the effects of these comorbidities on patient management, therapeutic strategies, and clinical outcomes, an ideal animal model should develop cancer on the background of representative comorbid conditions (tumor macro- and microenvironments). As observed in clinical practice, liver cirrhosis frequently precedes development of primary liver cancer or hepatocellular carcinoma. The OCM has the capacity to develop tumors in combination with such relevant comorbidities. Furthermore, studies on the tumor microenvironment demonstrate similarities between OCM and human cancer genomic landscapes. This review highlights the potential of this and other large animal platforms as transitional models to bridge the gap between basic research and clinical practice.

Goals and objectives of the Italian Network for Tumor Biotherapy (NIBIT)

The explosion in the immuno-oncology field, exemplified by the clinical implementation of immune checkpoint inhibitor blockade and other immunotherapeutic strategies was quickly recognized by the Italian biomedical community, thanks to the networking activities of the Italian Network for Tumor Biotherapy (NIBIT), which has been active since 2004 in the diffusion of new scientific and clinical findings in the fields of tumor immunology and immunotherapy. Numerous activities of NIBIT have also helped to overcome the hurdles associated with the clinical implementation of cancer immune-biotherapeutic strategies at the national and international levels. Looking forward, a concerted interaction of NIBIT with existing European networks focused on cancer bio-immunotherapy will further contribute to the development of improved therapies in the immuno-oncology field. This Introduction briefly summarizes the history and objectives of NIBIT, as well as the current activities of the Network.

TRAIL-NP hybrids for cancer therapy: a review

Cancer is a worldwide health problem. It is now considered as a leading cause of morbidity and mortality in developed countries. In the last few decades, considerable progress has been made in anti-cancer therapies, allowing the cure of patients suffering from this disease, or at least helping to prolong their lives. Several cancers, such as those of the lung and pancreas, are still devastating in the absence of therapeutic options. In the early 90s, TRAIL (Tumor Necrosis Factor-related apoptosis-inducing ligand), a cytokine belonging to the TNF superfamily, attracted major interest in oncology owing to its selective anti-tumor properties. Clinical trials using soluble TRAIL or antibodies targeting the two main agonist receptors (TRAIL-R1 and TRAIL-R2) have, however, failed to demonstrate their efficacy in the clinic. TRAIL is expressed on the surface of natural killer or CD8+ T activated cells and contributes to tumor surveillance. Nanoparticles functionalized with TRAIL mimic membrane-TRAIL and exhibit stronger antitumoral properties than soluble TRAIL or TRAIL receptor agonist antibodies. This review provides an update on the association and the use of nanoparticles associated with TRAIL for cancer therapy.

Epinephrine promotes COX-2-dependent immune suppression in myeloid cells and cancer tissues

Activation of the sympathetic nervous system (e.g., due to stress) has been implicated in cancer progression and recurrence, but its cancer-promoting effects have been variable between different studies. Here, we report that although catecholamines, mediators of systemic sympathetic activity, display only weak immunosuppressive impact on their own, their combination with inflammatory signals leads to the induction of COX-2 and multiple COX-2-dependent suppressive factors in human myeloid cells and cancer tissues. Human macrophages exposed to epinephrine and TNFα, or macrophages generated in 6day cultures in the presence of epinephrine, expressed high levels of COX-2, IDO and IL-10, and strongly suppressed both the proliferation and IFNγ production of CD8+ T cells. These suppressive effects of epinephrine were counteracted by celecoxib, a selective inhibitor of COX-2 activity, which inhibited the induction of immunosuppressive factors (including the elevated expression of COX-2 itself) and the ability of epinephrine-exposed macrophages to suppress CD8+ T cell responses. The activation of the COX-2/PGE2 system and COX-2-dependent suppressive events were also observed in ex vivo human breast and colon cancer explant cultures and were similarly counteracted by celecoxib. Our preliminary data also indicate elevated COX-2 expression in mammary tumors of chronic stress-exposed mice. The current demonstration of the interplay between inflammation and the induction of immunosuppressive factors by catecholamines suggest a contextual impact of stress, helping to explain variable results of epidemiologic studies of the link between sympathetic activity and cancer progression, and implicating COX-2 blockade as a potential means to mitigate stress-related immune suppression.

Immunotherapy of head and neck cancer: Emerging clinical trials from a National Cancer Institute Head and Neck Cancer Steering Committee Planning Meeting

Recent advances have permitted successful therapeutic targeting of the immune system in head and neck squamous cell carcinoma (HNSCC). These new immunotherapeutic targets and agents are being rapidly adopted by the oncologic community and hold considerable promise. The National Cancer Institute sponsored a Clinical Trials Planning Meeting to address the issue of how to further investigate the use of immunotherapy in patients with HNSCC. The goals of the meeting were to consider phase 2 or 3 trial designs primarily in 3 different patient populations: those with previously untreated, human papillomavirus-initiated oropharyngeal cancers; those with previously untreated, human papillomavirus-negative HNSCC; and those with recurrent/metastatic HNSCC. In addition, a separate committee was formed to develop integrative biomarkers for the clinical trials. The meeting started with an overview of key immune components and principles related to HNSCC, including immunosurveillance and immune escape. Four clinical trial concepts were developed at the meeting integrating different immunotherapies with existing standards of care. These designs were presented for implementation by the head and neck committees of the National Cancer Institute-funded National Clinical Trials Network. This article summarizes the proceedings of this Clinical Trials Planning Meeting, the purpose of which was to facilitate the rigorous development and design of randomized phase 2 and 3 immunotherapeutic trials in patients with HNSCC. Although reviews usually are published immediately after the meeting is held, this report is unique because there are now tangible clinical trial designs that have been funded and put into practice and the studies are being activated to accrual. Cancer 2017;123:1259-1271. © 2016 American Cancer Society.

Biomarkers for Immunotherapy: Current Developments and Challenges

Immunotherapy has revolutionized cancer therapy and has been named the cancer advance of the year for 2016. Checkpoint inhibitors have demonstrated unprecedented rates of durable responses in some of the most difficult-to-treat cancers; however, many treated patients do not respond, and the potential for serious side effects exists. There is a growing need to identify biomarkers that will improve the selection of patients who will best respond to therapy, further elucidate drug mechanisms of action, and help tailor therapy regimens. Biomarkers are being explored at the soluble, cellular, and genomic levels, and examples in immunotherapy include serum proteins, tumor-specific receptor expression patterns, factors in the tumor microenvironment, circulating immune and tumor cells, and host genomic factors. The search for reliable biomarkers is limited by our incomplete understanding of how immunotherapies modify the already complex immune response to cancer, as well as the contribution of immuno-editing to a dynamic and inducible tumor microenvironment and immune milieu. Furthermore, there has been little extension of any candidate assay into large, prospective studies, and the lack of standardization in measurement and interpretation restricts their validity. Both tumor-infiltrating lymphocytes and PD-L1 expression within the tumor microenvironment have been recognized as having both prognostic and predictive value for patients treated with immunotherapy. Alternately, a larger panel of gene signatures, chemokines, and other factors that correlate with response has been proposed. In this article, we will explore the status of current biomarker candidates.

The importance of correctly timing cancer immunotherapy

INTRODUCTION

The treatment options for cancer-surgery, radiotherapy and chemotherapy-are now supplemented with immunotherapy. Previously underappreciated but now gaining strong interest are the immune modulatory properties of the three conventional modalities. Moreover, there is a better understanding of the needs and potential of the different immune therapeutic platforms. Key to improved treatment will be the combinations of modalities that complete each other's shortcomings. Area covered: Tumor-specific T-cells are required for optimal immunotherapy. In this review, the authors focus on the correct timing of different types of chemotherapeutic agents or immune modulators and immunotherapeutic drugs, not only for the activation and expansion of tumor-specific T-cells but also to support and enhance their anti-tumor efficacy. Expert opinion: At an early phase of disease, clinical success can be obtained using single treatment modalities but at later disease stages, combinations of several modalities are required. The gain in success is determined by a thorough understanding of the direct and indirect immune effects of the modalities used. Profound knowledge of these effects requires optimal tuning of immunomonitoring. This will guide the appropriate combination of treatments and allow for correct sequencing the order and interval of the different therapeutic modalities.

Employing dynamical computational models for personalizing cancer immunotherapy

INTRODUCTION

Recently, cancer immunotherapy has shown considerable success, but due to the complexity of the immune-cancer interactions, clinical outcomes vary largely between patients. A possible approach to overcome this difficulty may be to develop new methodologies for personal predictions of therapy outcomes, by the integration of patient data with dynamical mathematical models of the drug-affected pathophysiological processes.

AREAS COVERED

This review unfolds the story of mathematical modeling in cancer immunotherapy, and examines the feasibility of using these models for immunotherapy personalization. The reviewed studies suggest that response to immunotherapy can be improved by patient-specific regimens, which can be worked out by personalized mathematical models. The studies further indicate that personalized models can be constructed and validated relatively early in treatment.

EXPERT OPINION

The suggested methodology has the potential to raise the overall efficacy of the developed immunotherapy. If implemented already during drug development it may increase the prospects of the technology being approved for clinical use. However, schedule personalization, per se, does not comply with the current, 'one size fits all,' paradigm of clinical trials. It is worthwhile considering adjustment of the current paradigm to involve personally tailored immunotherapy regimens.

COTI-2, a novel small molecule that is active against multiple human cancer cell lines in vitro and in vivo

Identification of novel anti-cancer compounds with high efficacy and low toxicity is critical in drug development. High-throughput screening and other such strategies are generally resource-intensive. Therefore, in silico computer-aided drug design has gained rapid acceptance and popularity. We employed our proprietary computational platform (CHEMSAS®), which uses a unique combination of traditional and modern pharmacology principles, statistical modeling, medicinal chemistry, and machine-learning technologies to discover and optimize novel compounds that could target various cancers. COTI-2 is a small molecule candidate anti-cancer drug identified using CHEMSAS. This study describes the in vitro and in vivo evaluation of COTI-2. Our data demonstrate that COTI-2 is effective against a diverse group of human cancer cell lines regardless of their tissue of origin or genetic makeup. Most treated cancer cell lines were sensitive to COTI-2 at nanomolar concentrations. When compared to traditional chemotherapy or targeted-therapy agents, COTI-2 showed superior activity against tumor cells, in vitro and in vivo. Despite its potent anti-tumor efficacy, COTI-2 was safe and well-tolerated in vivo. Although the mechanism of action of COTI-2 is still under investigation, preliminary results indicate that it is not a traditional kinase or an Hsp90 inhibitor.

TARP vaccination is associated with slowing in PSA velocity and decreasing tumor growth rates in patients with Stage D0 prostate cancer

T-cell receptor alternate reading frame protein (TARP) is a 58-residue protein over-expressed in prostate and breast cancer. We investigated TARP peptide vaccination's impact on the rise in PSA (expressed as Slope Log(PSA) or PSA Doubling Time (PSADT)), validated tumor growth measures, and tumor growth rate in men with Stage D0 prostate cancer. HLA-A*0201 positive men were randomized to receive epitope-enhanced (29-37-9V) and wild-type (27-35) TARP peptides administered as a Montanide/GM-CSF peptide emulsion or as an autologous peptide-pulsed dendritic cell vaccine every 3 weeks for a total of five vaccinations with an optional 6th dose of vaccine at 36 weeks based on immune response or PSADT criteria with a booster dose of vaccine for all patients at 48 and 96 weeks. 41 patients enrolled with median on-study duration of 75 weeks at the time of this analysis. Seventy-two percent of patients reaching 24 weeks and 74% reaching 48 weeks had a decreased Slope Log(PSA) compared to their pre-vaccination baseline (p = 0.0012 and p = 0.0004 for comparison of overall changes in Slope Log(PSA), respectively). TARP vaccination also resulted in a 50% decrease in median tumor growth rate (g): pre-vaccine g = 0.0042/day, post-vaccine g = 0.0021/day (p = 0.003). 80% of subjects exhibited new vaccine-induced TARP-specific IFNγ ELISPOT responses but they did not correlate with decreases in Slope Log(PSA). Thus, vaccination with TARP peptides resulted in significant slowing in PSA velocity and reduction in tumor growth rate in a majority of patients with PSA biochemical recurrence.

Immunotherapy in non-small cell lung cancer: the clinical impact of immune response and targeting

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related death worldwide. In recent years, through a better understanding of the interactions between the immune system and tumor cells (TC), immunotherapy has emerged as a promising therapeutic strategy. Chemotherapy has long been reported to interfere with the immune response to the tumor and conversely, anti-tumor immunity may add to those effects. Anti-tumor vaccines, such as MAGE-A3, Tecetomide, TG4010, CIMAvax, tumor cell vaccines and dendritic cell (DC) vaccines emerged as potent inducers of the immune response against the tumor. More recently the approval of the anti-programmed cell death 1 (anti-PD-1) monoclonal antibodies nivolumab and pembrolizumab for previously treated advanced squamous and non-squamous NSCLC, as well as other immune checkpoint inhibitors delivering promising results, has radically transformed the therapeutic landscape of NSCLC. Combination strategies now appear as the next step. Notwithstanding these successes, immunotherapy still holds significant drawbacks and currently several improvements are needed before routine use in clinical practice, including identification of robust biomarkers for optimal patient selection, as well as defining the best way to evaluate response.

Distinct mechanisms of B and T lymphocyte accumulation generate tumor-draining lymph node hypertrophy

Tumor-draining lymph nodes (TDLNs) often enlarge in human cancer patients and in murine tumor models, due to lymphocyte accumulation and lymphatic sinus growth. B lymphocytes within TDLNs can drive lymph node hypertrophy in response to tumor growth, however little is known about the mechanisms directing the preferential accumulation of B lymphocytes relative to T cells in enlarging TDLNs. To define why B and T lymphocytes accumulate in TDLNs, we quantified lymphocyte proliferation, apoptosis, entry, and exit in TDLNs versus contralateral non-TDLNs (NTDLNs) in a footpad B16-F10 melanoma mouse model. B and T lymphocyte proliferation and apoptosis were increased as the TDLNs enlarged, although relative rates were similar to those of NTDLNs. TDLN entry of B and T lymphocytes via high endothelial venules was also modestly increased in enlarged TDLNs. Strikingly, the egress of B cells was strongly reduced in TDLNs versus NTDLNs, while T cell egress was modestly decreased, indicating that regulation of lymphocyte exit from TDLNs is a major mechanism of preferential B lymphocyte accumulation. Surface sphingosine-1-phosphate receptor 1 (S1PR1) which binds S1P and signals lymphocyte egress, exhibited greater downregulation in B relative to T lymphocytes, consistent with preferential retention of B lymphocytes in TDLNs. TDLN lymphocytes did not activate surface CD69 expression, indicating a CD69-independent mechanism of downregulation of S1PR1. B and T cell trafficking via afferent lymphatics to enter TDLNs also increased, suggesting a pathway for accumulation of tumor-educated lymphocytes in TDLNs. These mechanisms regulating TDLN hypertrophy could provide new targets to manipulate lymphocyte responses to cancer.

Current status and perspectives in translational biomarker research for PD-1/PD-L1 immune checkpoint blockade therapy

Modulating immune inhibitory pathways has been a major recent breakthrough in cancer treatment. Checkpoint blockade antibodies targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programed cell-death protein 1 (PD-1) have demonstrated acceptable toxicity, promising clinical responses, durable disease control, and improved survival in some patients with advanced melanoma, non-small cell lung cancer (NSCLC), and other tumor types. About 20 % of advanced NSCLC patients and 30 % of advanced melanoma patients experience tumor responses from checkpoint blockade monotherapy, with better clinical responses seen with the combination of anti-PD-1 and anti-CTLA-4 antibodies. Given the power of these new therapies, it is important to understand the complex and dynamic nature of host immune responses and the regulation of additional molecules in the tumor microenvironment and normal organs in response to the checkpoint blockade therapies. In this era of precision oncology, there remains a largely unmet need to identify the patients who are most likely to benefit from immunotherapy, to optimize the monitoring assays for tumor-specific immune responses, to develop strategies to improve clinical efficacy, and to identify biomarkers so that immune-related adverse events can be avoided. At this time, PD-L1 immunohistochemistry (IHC) staining using 22C3 antibody is the only FDA-approved companion diagnostic for patients with NSCLC-treated pembrolizumab, but more are expected to come to market. We here summarize the current knowledge, clinical efficacy, potential immune biomarkers, and associated assays for immune checkpoint blockade therapies in advanced solid tumors.

Adjuvant Autologous Melanoma Vaccine for Macroscopic Stage III Disease: Survival, Biomarkers, and Improved Response to CTLA-4 Blockade

Background. There is not yet an agreed adjuvant treatment for melanoma patients with American Joint Committee on Cancer stages III B and C. We report administration of an autologous melanoma vaccine to prevent disease recurrence. Patients and Methods. 126 patients received eight doses of irradiated autologous melanoma cells conjugated to dinitrophenyl and mixed with BCG. Delayed type hypersensitivity (DTH) response to unmodified melanoma cells was determined on the vaccine days 5 and 8. Gene expression analysis was performed on 35 tumors from patients with good or poor survival. Results. Median overall survival was 88 months with a 5-year survival of 54%. Patients attaining a strong DTH response had a significantly better (p = 0.0001) 5-year overall survival of 75% compared with 44% in patients without a strong response. Gene expression array linked a 50-gene signature to prognosis, including a cluster of four cancer testis antigens: CTAG2 (NY-ESO-2), MAGEA1, SSX1, and SSX4. Thirty-five patients, who received an autologous vaccine, followed by ipilimumab for progressive disease, had a significantly improved 3-year survival of 46% compared with 19% in nonvaccinated patients treated with ipilimumab alone (p = 0.007). Conclusion. Improved survival in patients attaining a strong DTH and increased response rate with subsequent ipilimumab suggests that the autologous vaccine confers protective immunity.

Immune Cell-Conditioned Media Suppress Prostate Cancer PC-3 Cell Growth Correlating With Decreased Proinflammatory/Anti-inflammatory Cytokine Ratios in the Media Using 5 Selected Crude Polysaccharides

Five different crude polysaccharides from guava seed (GSPS), bitter buckwheat (BBPS), common buckwheat (CBPS), red Formosa lambsquarters (RFLPS), and yellow Formosa lambsquarters (YFLPS) were isolated to treat human prostate cancer PC-3 cells via direct action or tumor immunotherapy. The splenocyte- and macrophage-conditioned media (SCM and MCM) were prepared using individual selected polysaccharides, and then SCM or MCM was further collected to treat PC-3 cells. The relationship between PC-3 cell growth and Th1/Th2 cytokines in SCM as well as proinflammatory/anti-inflammatory cytokine secretion profiles in MCM were delineated. The results showed that all 5 selected polysaccharides did not significantly inhibit PC-3 cell growth via direct action. However, SCM or MCM cultured in the absence or presence of 5 selected polysaccharides significantly (P < .05) inhibited PC-3 cell growth. MCM cultured with 5 polysaccharides dose dependently enhanced their inhibitory effects on the viabilities of PC-3 cells than those cultured without polysaccharides. There was a significant (P < .05) negative correlation between PC-3 cell viabilities and (interleukin [IL]-6 + tumor necrosis factor [TNF]-α)/IL-10 level ratios in the corresponding MCM, implying that macrophages suppress PC-3 cell growth through decreasing secretion ratios of proinflammatory/anti-inflammatory cytokines in a tumor microenvironment.