Overall survival analysis of a phase II randomized controlled trial of a Poxviral-based PSA-targeted immunotherapy in metastatic castration-resistant prostate cancer

mRNA vaccines for prostate cancer: A novel promising immunotherapy

The treatment of advanced prostate cancer (PCa) primarily based on androgen deprivation therapy (ADT); however, patients inevitably progress to the castration-resistant prostate cancer (CRPC) stage. Despite the recent advancements in CRPC treatment with novel endocrine drugs that further inhibit androgen receptor signaling, resistance ultimately develops, underscoring the urgent need for new effective therapeutic strategies. Therapeutic cancer vaccines, a form of immunotherapy, exert anti-cancer effects by activating the host's immune system. Over the past few decades, various conventional therapeutic PCa vaccines based on cells, microbes, proteins, peptides, or DNA have been developed and tested in patients with advanced PCa. These attempts have largely failed to improve survival, with the sole exception of sipuleucel-T, which extended the median overall survival of asymptomatic or minimally symptomatic metastatic CRPC (mCRPC) patients by four months. The rapid development and high efficacy of mRNA vaccines during the COVID-19 pandemic have garnered worldwide attention. Compared to conventional vaccines, mRNA vaccines offer several unique advantages, including high production efficiency, low cost, high safety, strong immune response induction, and high adaptability and precision. These attributes make mRNA vaccines a promising frontier in the treatment of advanced PCa.

A Reverse Vaccinology and Immunoinformatic Approach for the Designing of a Novel mRNA Vaccine Against Stomach Cancer Targeting the Potent Pathogenic Proteins of Helicobacter pylori

Helicobacter pylori infection of the stomach's epithelial cells is a significant risk factor for stomach cancer. Various H pylori proteins (CagA, GGT, NapA, PatA, urease, and VacA) were targeted to design 2 messenger RNA (mRNA) vaccines, V1 and V2, using bioinformatics tools. Physicochemical parameters, secondary and tertiary structure, molecular docking and dynamic simulation, codon optimization, and RNA structure prediction have also been estimated for these developed vaccines. Physicochemical analyses revealed that these developed vaccines are soluble (GRAVY < 0), basic (pI < 7), and stable (aliphatic index < 80). The secondary and tertiary structure of the vaccines demonstrated robustness. The docking with toll-like receptors (TLRs) revealed that the vaccines have a potential affinity for TLR-2 (V1: -1132.3 kJ/mol, V2: -1093.6 kJ/mol) and TLR-4 (V1: -1042.7 kJ/mol, V2: -1201.2 kJ/mol), and molecular dynamics simulations confirmed their dynamic stability. Structural analyses of V1 (-505.96 kcal/mol) and V2 (-634.92 kcal/mol) mRNA vaccines underscored their stability. In addition, the vaccine showed a considerable rise in the counts of B cells and extended activation of both T cells was also observed for the vaccines, suggesting the potential for long-lasting immunity, and offering enhanced protection against H pylori. These findings not only suggest potential long-lasting immunity against H pylori but also offer hope for the future of stomach cancer prevention. Notably, the study emphasizes the need for subsequent animal and human-based studies to confirm these promising results.

Targeting prostate cancer by new bispecific monocyte engager directed to prostate-specific membrane antigen

Prostate cancer (PCa) ranks as the second leading cause of cancer-related deaths among men in the United States. Prostate-specific membrane antigen (PSMA) represents a well-established biomarker of PCa, and its levels correlate positively with the disease progression, culminating at the stage of metastatic castration-resistant prostate cancer. Due to its tissue-specific expression and cell surface localization, PSMA shows superior potential for precise imaging and therapy of PCa. Antibody-based immunotherapy targeting PSMA offers the promise of selectively engaging the host immune system with minimal off-target effects. Here we report on the design, expression, purification, and characterization of a bispecific engager, termed 5D3-CP33, that efficiently recruits macrophages to the vicinity of PSMA-positive cancer cells mediating PCa death. The engager was engineered by fusing the anti-PSMA 5D3 antibody fragment to a cyclic peptide 33 (CP33), selectively binding the Fc gamma receptor I (FcγRI/CD64) on the surface of phagocytes. Functional parts of the 5D3-CP33 engager revealed a nanomolar affinity for PSMA and FcγRI/CD64 with dissociation constants of KD =  3 nM and KD =  140 nM, respectively. At a concentration as low as 0.3 nM, the engager was found to trigger the production of reactive oxygen species by U937 monocytic cells in the presence of PSMA-positive cells. Moreover, flow cytometry analysis demonstrated antibody-dependent cell-mediated phagocytosis of PSMA-positive cancer cells by U937 monocytes when exposed to 0.15 nM 5D3-CP33. Our findings illustrate that 5D3-CP33 effectively and specifically activates monocytes upon PSMA-positive target engagement, resulting in the elimination of tumor cells. The 5D3-CP33 engager can thus serve as a promising lead for developing new immunotherapy tools for the efficient treatment of PCa.

Comparative therapeutic efficacy and safety of first-line and second-line therapies for metastatic castration-resistant prostate cancer: a systematic review and network meta-analysis

Background

There is no cross-sectional comparison on therapeutic and adverse effects for treatments of metastatic castration-resistant prostate cancer (mCRPCa). We aimed to horizontally compare them for all common first-line and second-line therapies.

Methods

We conducted a network meta-analysis with a systematic review in four databases (Pubmed, Web of Science, Embase, and Cochrane Library) up to January 5th, 2025. All randomized controlled trials (RCT) related to mCRPCa treatments with a clear description in study design were included. Endpoints included the radiographic progression-free survival (rPFS), overall survival (OS), time to PSA progression (TTPP), PSA progression rate (PSARR), and adverse events. All data was extracted by two researchers and analyzed with Gemtc package in R and Stata15. This NMA protocol was registered online (ID: CRD42025633178).

Findings

After screening among 33,694 articles, 24 RCTs involving 13,059 cases were included. For first-line treatments, combination therapies with second-generation androgen receptor inhibitors (ARIs) showed superior efficacies in OS [HR of poly(ADP-ribose) polymerase inhibitors (PARPi) + ARI: 0.63 (0.32,1.25)], TTPP [HR of Lu177 + ARI: 0.07 (0.01,0.87)] and PSARR [RR of Lu177 + ARI: 33.02 (15.56,71.62)] with the highest SUCRA (Surface under the Cumulative Ranking Curve) (72%, 91% and 97% respectively). PARPi + ARI also performed best for rPFS (SUCRA: 85%, with an insignificant HR [0.12 (0.02,2.35)]. For post-docetaxel second-line treatments, ARI also emerged as the preferred option. Efficacies of post-ARI second-line treatments were not evaluated due to the lack of related RCTs. No obvious heterogeneity and publication bias was detected during the therapeutic comparison.

Interpretation

This study provided comparative evidence for first-line and post-chemotherapy second-line mCRPCa treatment options. Second-generation ARIs exhibited good efficacy, particularly when combined with other treatments. However, the safety analysis necessitated balance between benefits and adverse events, especially for combination therapies. Stronger evidence is needed through direct comparisons in future clinical trials.

Funding

The study was supported by The National Natural Science Foundation of China (No. 82172568).

Metal nanoparticles as a promising therapeutic approach for prostate cancer diagnosis and therapy: a comprehensive review

Prostate cancer is a leading cause of mortality among men worldwide, particularly in the USA and European nations, with an estimated 1.9 million new cases and over 580,000 deaths annually, according to recent global statistics. The treatment of prostate tumors presents significant clinical challenges, due to the disease's high metastatic potential, specifically to vital organs, such as the liver, lungs, bones, and brain. The intrinsic heterogeneity of prostate cancer cells, characterized by diverse genetic, molecular, and phenotypic profiles, complicates conventional therapeutic strategies, highlighting the need for advanced diagnostic and treatment modalities. Nanoparticles play a critical role in oncology field due to their unique physicochemical properties, including high surface area-to-volume ratio and the ability to be functionalized with targeting ligands. Metallic-based nanoparticles exhibits significant potential for applications in field of nanomedicine, drug delivery systems, gene silencing methods, radiotherapy enhancement, cancer diagnostics, and targeted therapeutic interventions. Metal nanoparticles have substantially improved the sensitivity and specificity of major imaging modalities and have demonstrated remarkable efficacy as biosensors for the detection of prostate cancer-specific biomarkers. This review article provides an in-depth analysis of the utilization of metal nanomaterials in prostate cancer, focusing on their roles in enhancing therapeutic efficacy, advancing diagnostic precision, and supporting the development of novel treatment strategies.

Cancer vaccines: current status and future directions

Cancer continues to be a major global health burden, with high morbidity and mortality. Building on the success of immune checkpoint inhibitors and adoptive cellular therapy, cancer vaccines have garnered significant interest, but their clinical success remains modest. Benefiting from advancements in technology, many meticulously designed cancer vaccines have shown promise, warranting further investigations to reach their full potential. Cancer vaccines hold unique benefits, particularly for patients resistant to other therapies, and they offer the ability to initiate broad and durable T cell responses. In this review, we highlight the antigen selection for cancer vaccines, introduce the immune responses induced by vaccines, and propose strategies to enhance vaccine immunogenicity. Furthermore, we summarize key features and notable clinical advances of various vaccine platforms. Lastly, we delve into the mechanisms of tumor resistance and explore the potential benefits of combining cancer vaccines with standard treatments and other immunomodulatory approaches to improve vaccine efficacy.

Biomaterial-Based Therapeutic Delivery of Immune Cells

Immune cell therapy (ICT) is a transformative approach used to treat a wide range of diseases including type 1 diabetes, sickle cell disease, disorders of the hematopoietic system, and certain forms of cancers. Despite excellent clinical successes, the scope of adoptively transferred immune cells is limited because of toxicities like cytokine release syndrome and immune effector cell-associated neurotoxicity in patients. Furthermore, reports suggest that such treatment can impact major organ systems including cardiac, renal, pulmonary, and hepatic systems in the long term. Additionally, adoptively transferred immune cells cannot achieve significant penetration into solid tissues, thus limiting their therapeutic potential. Recent studies suggest that biomaterial-assisted delivery of immune cells can address these challenges by reducing toxicity, improving localization, and maintaining desired phenotypes to eventually regain tissue function. In this review, recent efforts in the field of biomaterial-based immune cell delivery for the treatment of diseases, their pros and cons, and where these approaches stand in terms of clinical treatment are highlighted.

Advancing Cancer Vaccines with Radionuclide Imaging

Cancer vaccines are emerged as a beacon of hope in the fight against cancer. However, the lack of effective methods to directly observe their in vivo behavior and monitor therapeutic responses hinders their translation into clinical settings. Radionuclide imaging allows for non-invasive and real-time visualization of vaccine biodistribution and immunological response, offering valuable insights into the effectiveness of cancer vaccines and aiding in patient stratification. In this review, the latest advances and potential applications of radionuclide imaging in cancer vaccines are discussed, with a specific focus on strategies for visualizing the spatiotemporal distribution of vaccines in vivo and monitoring treatment efficacy. The challenges and considerations for implementing these techniques in clinical practice are also highlighted, aiming to inform and guide future research in this field.

Long-term follow up of patients treated with a DNA vaccine (pTVG-hp) for PSA-recurrent prostate cancer

We have previously reported two single-agent phase I trials, evaluating the dose or schedule, of a DNA vaccine (pTVG-HP) encoding prostatic acid phosphatase (PAP) administered with GM-CSF as the adjuvant. These were in patients with PSA-recurrent, radiographically non-metastatic, prostate cancer (PCa). We report here the long-term safety and overall survival of these patients. Specifically, 22 patients with non-metastatic, castration-sensitive PCa (nmCSPC) were treated with pTVG-HP, 100-1500 µg, administered over 12 weeks and followed for 15 y. 17 patients with non-metastatic castration-resistant PCa (nmCRPC) were treated with 100 µg pTVG-HP with different schedules of administration over 1 y and followed for 5 y. No adverse events were detected in long-term follow-up from either trial that were deemed possibly related to vaccination. Patients with nmCSPC had a median overall survival of 12.3 y, with 5/22 (23%) alive at 15 y. 8/22 (36%) died due to prostate cancer with a median survival of 11.0 y, and 9/22 (41%) died of other causes. Patients with nmCRPC had a median overall survival of 4.5 y, with 8/17 (47%) alive at 5 y. The presence of T-cells specific for the PAP target antigen was detectable in 6/10 (60%) individuals with nmCSPC, and 3/5 (60%) individuals with nmCRPC, many years after immunization. The detection of immune responses to the vaccine target years after immunization suggests durable immunity can be elicited in patients using a DNA vaccine encoding a tumor-associated antigen.Trial Registration: NCT00582140 and NCT00849121.

Immunological facets of prostate cancer and the potential of immune checkpoint inhibition in disease management

Prostate cancer (PCa) is the most common non-cutaneous cancer in men and a major cause of cancer-related deaths. Whereas localized PCa can be cured by surgery and radiotherapy, metastatic disease can be treated, but is not curable. Inhibition of androgen signaling remains the main therapeutic intervention for treatment of metastatic PCa, in addition to chemotherapy, radionuclide therapy and emerging targeted therapies. Although initial responses are favorable, resistance to these therapies invariably arise with development of castration resistant PCa (CRPC) and lethal phenotypes. Recent findings have implicated the crosstalk between PCa cells and the tumor microenvironment (TME) as a key factor for disease progression and metastasis, and the immune system is becoming an increasingly attractive target for therapy. Given the striking success of immune checkpoint inhibitors (ICIs) in various cancer types, preclinical and clinical studies have begun to explore their potential in PCa. It has become clear that the PCa TME is largely immunosuppressive, and ICI therapy does not have efficacy for PCa. Intense effort is therefore being made in the field to understand the mechanisms of suppression and to turn the immunosuppressive TME into an immune active one that would enable ICI efficacy. Herein we examine this recent body of knowledge and how the mutational landscape of PCa integrates with an immunosuppressive TME to circumvent ICI-mediated T-cell activity and tumor killing. We then review the emerging potential success of combinatorial ICI approaches, utility of careful patient selection, and potential novel strategies to improve the efficacy of ICI for PCa therapy.

Kallikrein-related peptidases: mechanistic understanding for potential therapeutic targeting in cancer

INTRODUCTION

Human kallikrein-related peptidases (KLKs) represent a subgroup of 15 serine endopeptidases involved in various physiological processes and pathologies, including cancer.

AREAS COVERED

This review aims to provide a comprehensive overview of the KLK family, highlighting their genomic structure, expression profiles and substrate specificity. We explore the role of KLKs in tumorigenesis, emphasizing their potential as biomarkers and therapeutic targets in cancer treatment. The dysregulated activity of KLKs has been linked to various malignancies, making them promising candidates for cancer diagnostics and therapy.

EXPERT OPINION

: Recent advancements in understanding the mechanistic pathways of KLK-related tumorigenesis offer new prospects for developing targeted cancer treatments. Expert opinion suggests that while significant progress has been made, further research is necessary to fully exploit KLKs' potential in clinical applications.

Prostate cancer stem cells and their targeted therapies

Prostate cancer (PCa) is the most common malignancy among men worldwide. Through androgen receptor signaling inhibitor (ARSI) treatment, patients eventually succumb to castration-resistant prostate cancer (CRPC). For this, the prostate cancer stem cells (PCSCs), as a minor population of tumor cells that can promote tumor relapse, ARSI resistance, and disease progression, are gaining attention. Therefore, specific therapy targeting PCSCs has momentum. This study reviewed the identification and characterization of PCSCs and PCSC-based putative biomarkers and summarized their mechanisms of action. We further discussed clinical trials of novel therapeutic interventions focused on PCSC-related pathways, the PCSC microenvironment, cutting-edge miRNA therapy, and immunotherapy approaches from a mechanistic standpoint. This review provides updated insights into PCSC plasticity, identifying new PCSC biomarkers and optimized treatments for patients with advanced PCa.

Public neoantigens in breast cancer immunotherapy (Review)

Among women globally, breast cancer is the most prevalent cancer and the leading cause of cancer‑related death. Interestingly, though genetic mutations contribute to the disease, <15% of women diagnosed with breast cancer have a family history of the disease, suggesting a prevalence of sporadic genetic mutations in breast cancer development. In the rapidly rising field of cancer genomics, neoantigen‑based immunotherapy has come to the fore. The investigation of novel proteins arising from unique somatic mutations or neoantigens have opened a new pathway for both individualized and public cancer treatments. Because they are shared among individuals with similar genetic changes, public neoantigens provide an opportunity for 'off‑the‑shelf' anticancer therapies, potentially extending the benefits to a wider patient group. The present review aimed to highlight the role of shared or public neoantigens as therapeutic targets for patients with breast cancer, emphasizing common hotspot mutations of certain genes identified in breast cancer. The clinical utilization of public neoantigen‑based therapies for breast cancer treatment were also discussed.

Generation of the therapeutic monoclonal antibody NEO-201, derived from a cancer vaccine, which targets human malignancies and immune suppressor cells

INTRODUCTION

Cancer vaccines stimulate the activation of specific humoral and cellular adaptive responses against cancer cells.Antibodies generated post vaccination can be isolated and further selected to develop highly specific and potent monoclonal antibodies (mAbs) against tumor-associated antigens.

AREAS COVERED

This review describes different types of cancer vaccines, the process of the generation of the mAb NEO-201 from the Hollinshead cancer vaccine platform, the characterization of the antigen recognized by NEO-201, the ability of NEO-201 to bind and mediate the killing of cancer cells and immunosuppressive cells (gMDSCs and Tregs) through ADCC and CDC, NEO-201 preclinical and clinical toxicity and efficacy.

EXPERT OPINION

To overcome the problem of poor clinical efficacy of cancer vaccines, due to the activity of immunosuppressive cells, cancer vaccines could be combined with other immunotherapeutics able to deplete immunosuppressive cells. Results from clinical trials, employing NEO-201 alone or in combination with pembrolizumab, showed that durable stabilization of disease after treatment was due to the ability of NEO-201 to target and reduce the percentage of circulating Tregs and gMDSCs.These findings provide compelling support to combine NEO-201 with cancer vaccines to reintegrate their ability to elicit a robust and durable immune adaptive response against cancer.

Targeting tumor and bone microenvironment: Novel therapeutic opportunities for castration-resistant prostate cancer patients with bone metastasis

Despite standard hormonal therapy that targets the androgen receptor (AR) attenuates prostate cancer (PCa) effectively in the initial stage, the tumor ultimately converts to castration-resistant prostate cancer (CRPC), and the acquired resistance is still a great challenge for the management of advanced prostate cancer patients. The tumor microenvironment (TME) consists of multiple cellular and noncellular agents is well known as a vital role during the development and progression of CRPC by establishing communication between TME and tumor cells. Additionally, as primary prostate cancer progresses towards metastasis, and CRPC always experiences bone metastasis, the TME is conducive to the spread of tumors to the distant sits, particularly in bone. In addition, the bone microenvironment (BME) is also closely related to the survival, growth and colonization of metastatic tumor cells. The present review summarized the recent studies which mainly focused on the role of TME or BME in the CRPC patients with bone metastasis, and discussed the underlying mechanisms, as well as the potential therapeutic values of targeting TME and BME in the management of metastatic CRPC patients.

Association of WHSC1/NSD2 and T-cell infiltration with prostate cancer metastasis and prognosis

Progress in immunotherapy for prostate cancer (PCa) lags that for other cancers, mainly because of limited immune infiltration in PCa. This study aimed to assess the feasibility of NSD2 as an immunotherapeutic target in PCa. Immunohistochemistry was performed to evaluate the expression pattern of NSD2 in 34 cases of benign prostatic hyperplasia (BPH), 36 cases of prostatic intraepithelial neoplasia (PIN), and 57 cases of PCa, including 19 cases of metastatic castration-resistant prostatic cancer (mCRPC). Single-cell RNA sequencing and gene set enrichment analysis (GSEA) were used to correlate NSD2 with certain downstream pathways. Furthermore, the Immuno-Oncology-Biological-Research (IOBR) software package was used to analyze the potential roles of NSD2 in the tumor microenvironment. We found that the positive expression rate of NSD2 increased progressively in BPH, PIN and PCa. mCRPC had the highest staining intensity for NSD2. High NSD2 expression was positively correlated with the infiltration level of CD4+ tumor-infiltrating lymphocytes (TILs) and negatively correlated with that of CD8+ TILs. Importantly, a new immune classification based on NSD2 expression and CD4+ TILs and CD8+ TILs was successfully used to stratify PCa patients based on OS.PSA and CD4+ TILs are independent risk factors for PCa bone metastasis. This study demonstrates a novel role for NSD2 in defining immune infiltrate on in PCa and highlights the great potential for its application in immunotherapy response evaluation for prostate malignancies.

Tumour adaptation to immune factors: old and new ideas for cancer immunotherapy

The tumour is fully functional in the zone of action of immune mediators. Moreover, the tumour needs immune system mediators to survive. "Adaptation" refers to a tumour's ability to withstand the effect of harmful elements. This gives birth to a new form of antitumour therapy: blocking tumour adaptability pathways. In this review, we will look at (i) tumour adaptation mechanisms as a result of pro-tumour immunoediting, (ii) how understanding tumour-adaptive mechanisms has led to ideas for developing cancer immunotherapies, and (iii) prospects for using the adaptation theory to substantiate new approaches to tumour growth inhibition. By considering the cancer problem through the lens of adaptability, a unique strategy for enhancing the efficacy of immunotherapy was proposed. The new approach is to utilise antisense treatment to erase the structural trace of adaptation in tumour cells or to disadapt tumour cells by "turning off" the immune system before initiating immunotherapy.

Prostate Cancer in Transplant Receivers-A Narrative Review on Oncological Outcomes

Prostate cancer (PCa) is a low tumor mutational burden (TMB) cancer with a poor response to immunotherapy. Nonetheless, immunotherapy can be useful, especially in metastatic castration-resistant PCa (mCRPC). Increased cytotoxic T lymphocytes (CTLs) density is correlated with a shorter overall survival (OS), an early biochemical relapse, and a generally poor PCa prognosis. An increased number of CCR4+ regulatory T cells (CCR4 + Tregs) relates to a higher Gleason score or earlier progression. The same therapeutic options are available for renal transplant recipients (RTRs) as for the population, with a comparable functional and oncological outcome. Radical retropubic prostatectomy (RRP) is the most common method of radical treatment in RTRs. Brachytherapy and robot-assisted radical prostatectomy (RARP) seem to be promising therapies. Further studies are needed to assess the need for prostatectomy in low-risk patients before transplantation. The rate of adverse pathological features in RTRs does not seem to differ from those observed in the non-transplant population and the achieved cancer control seems comparable. The association between PCa and transplantation is not entirely clear. Some researchers indicate a possible association between a more frequent occurrence of PCa and a worse prognosis in advanced or metastatic PCa. However, others claim that the risk and survival prognosis is comparable to the non-transplant population.

Immunogenomic profiles associated with response to life-prolonging agents in prostate cancer

Prostate cancer is the most commonly diagnosed cancer but the management of advanced prostate cancer remains a therapeutic challenge, despite the survival benefits imparted by several therapeutic discoveries targeting different molecular pathways. The mechanisms of resistance to androgen deprivation and tumour progression to lethal metastatic variants are often regulated by androgen receptor (AR) bypass mechanisms and/or neuroendocrine differentiation. Moreover, recent data also suggested the involvement of adaptive and innate infiltrated immune cells in prostate tumour progression. Improvements in cancer genome analyses contributed to a better understanding of antitumour immunity and provided solutions for targeting highly cancer-specific neoantigens generated from somatic mutations in individual patients. In this review, we investigated the current knowledge on the interplay between cancer development and the complex mechanisms of immune regulation. Particularly, we focused on the role of tumour immune microenvironment, generally characterised by strong barriers for immunotherapy, and we discuss the rationale for the potential application of single agent and combination immune-targeting strategies that could lead to improved outcomes. Careful selection based on clinical and genomic factors may allow identification of patients who could benefit from this treatment approach in multiple settings (from localised to advanced prostate tumour) and in different histological subtypes (from adenocarcinoma to neuroendocrine prostate cancer).

[Research Progress of Lung Cancer Vaccines]

With the development of medical technology, tumor vaccines as a novel precise immunotherapy approach have gradually received attention in clinical applications. Against the backdrop of the global corona virus disease 2019 (COVID-19) outbreak, vaccine technology has further advanced. Depending on the types of antigens, tumor vaccines can be divided into whole-cell vaccines, peptide vaccines, messenger ribonucleic acid (mRNA) vaccines, recombinant virus vaccines, etc. Although some tumor vaccines have been marketed and achieved certain therapeutic effects, the results of tumor vaccines in clinical trials have been unsatisfactory in the past period. With the maturation of next-generation sequencing (NGS) technology and the continuous development of bioinformatics, dynamic monitoring of the entire process of tumor subpopulation development has become a reality, which has laid a solid foundation for personalized, neoantigen-centered therapeutic tumor vaccines. This article reviews the recent developments of tumor vaccines of different types, starts with lung cancer and summarizes the achievements of tumor vaccines in clinical applications, and provides an outlook for the future development of antigen-centered tumor vaccines.
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Vaccines as treatments for prostate cancer

Prostate cancer is a leading cause of death in men worldwide. For over 30 years, growing interest has focused on the development of vaccines as treatments for prostate cancer, with the goal of using vaccines to activate immune cells capable of targeting prostate cancer to either eradicate recurrent disease or at least delay disease progression. This interest has been prompted by the prevalence and long natural history of the disease and by the fact that the prostate is an expendable organ. Thus, an immune response elicited by vaccination might not need to target the tumour uniquely but could theoretically target any prostate tissue. To date, different vaccine approaches and targets for prostate cancer have been evaluated in clinical trials. Overall, five approaches have been assessed in randomized phase III trials and sipuleucel-T was approved as a treatment for metastatic castration-resistant prostate cancer, being the only vaccine approved to date by the FDA as a treatment for cancer. Most vaccine approaches showed safety and some evidence of immunological activity but had poor clinical activity when used as monotherapies. However, increased activity has been observed when these vaccines were used in combination with other immune-modulating therapies. This evidence suggests that, in the future, prostate cancer vaccines might be used to activate and expand tumour-specific T cells as part of combination approaches with agents that target tumour-associated immune mechanisms of resistance.

Preclinical and clinical trials of oncolytic vaccinia virus in cancer immunotherapy: a comprehensive review

Oncolytic virotherapy has emerged as a promising treatment for human cancers owing to an ability to elicit curative effects via systemic administration. Tumor cells often create an unfavorable immunosuppressive microenvironment that degrade viral structures and impede viral replication; however, recent studies have established that viruses altered via genetic modifications can serve as effective oncolytic agents to combat hostile tumor environments. Specifically, oncolytic vaccinia virus (OVV) has gained popularity owing to its safety, potential for systemic delivery, and large gene insertion capacity. This review highlights current research on the use of engineered mutated viruses and gene-armed OVVs to reverse the tumor microenvironment and enhance antitumor activity in vitro and in vivo, and provides an overview of ongoing clinical trials and combination therapies. In addition, we discuss the potential benefits and drawbacks of OVV as a cancer therapy, and explore different perspectives in this field.

Knowledge mapping of therapeutic cancer vaccine from 2013 to 2022: A bibliometric and visual analysis

The investigation of therapeutic cancer vaccines has been ongoing for the past century. Herein, we used VOSviewer and CiteSpace to perform the first global bibliometric analysis of the literature on therapeutic cancer vaccines from 2013 to 2022 aiming to explore the current status and potential research trends. The findings revealed a consistent upward trend in both publication counts and citations. The United States emerged as the leading contributor with the highest number of published papers. Additionally, the analysis of references and keywords indicated that therapeutic cancer vaccines have long been popular topics, whereas neoantigen vaccines, mRNA vaccines, combination strategies, and vaccine delivery systems are emerging research hotspots. This bibliometric study provides a comprehensive and important overview of the current knowledge and potential developments in therapeutic cancer vaccines from 2013 to 2022, which may serve as a valuable reference for scholars interested in further exploring this promising field.

The use of RNA-based treatments in the field of cancer immunotherapy

Over the past several decades, mRNA vaccines have evolved from a theoretical concept to a clinical reality. These vaccines offer several advantages over traditional vaccine techniques, including their high potency, rapid development, low-cost manufacturing, and safe administration. However, until recently, concerns over the instability and inefficient distribution of mRNA in vivo have limited their utility. Fortunately, recent technological advancements have mostly resolved these concerns, resulting in the development of numerous mRNA vaccination platforms for infectious diseases and various types of cancer. These platforms have shown promising outcomes in both animal models and humans. This study highlights the potential of mRNA vaccines as a promising alternative approach to conventional vaccine techniques and cancer treatment. This review article aims to provide a thorough and detailed examination of mRNA vaccines, including their mechanisms of action and potential applications in cancer immunotherapy. Additionally, the article will analyze the current state of mRNA vaccine technology and highlight future directions for the development and implementation of this promising vaccine platform as a mainstream therapeutic option. The review will also discuss potential challenges and limitations of mRNA vaccines, such as their stability and in vivo distribution, and suggest ways to overcome these issues. By providing a comprehensive overview and critical analysis of mRNA vaccines, this review aims to contribute to the advancement of this innovative approach to cancer treatment.

Potential of Personalized Dendritic Cell-Based Immunohybridoma Vaccines to Treat Prostate Cancer

Prostate cancer (PCa) is the most commonly diagnosed cancer and the second most common cause of death due to cancer. About 30% of patients with PCa who have been castrated develop a castration-resistant form of the disease (CRPC), which is incurable. In the last decade, new treatments that control the disease have emerged, slowing progression and spread and prolonging survival while maintaining the quality of life. These include immunotherapies; however, we do not yet know the optimal combination and sequence of these therapies with the standard ones. All therapies are not always suitable for every patient due to co-morbidities or adverse effects of therapies or both, so there is an urgent need for further work on new therapeutic options. Advances in cancer immunotherapy with an immune checkpoint inhibition mechanism (e.g., ipilimumab, an anti-CTLA-4 inhibitor) have not shown a survival benefit in patients with CRPC. Other immunological approaches have also not given clear results, which has indirectly prevented breakthrough for this type of therapeutic strategy into clinical use. Currently, the only approved form of immunotherapy for patients with CRPC is a cell-based medicine, but it is only available to patients in some parts of the world. Based on what was gained from recently completed clinical research on immunotherapy with dendritic cell-based immunohybridomas, the aHyC dendritic cell vaccine for patients with CRPC, we highlight the current status and possible alternatives that should be considered in the future.

The Clinical Advances of Oncolytic Viruses in Cancer Immunotherapy

A promising future for oncology treatment has been brought about by the emergence of a novel approach utilizing oncolytic viruses in cancer immunotherapy. Oncolytic viruses are viruses that have been exploited genetically to assault malignant cells and activate a robust immune response. Several techniques have been developed to endow viruses with an oncolytic activity through genetic engineering. For instance, redirection capsid modification, stimulation of anti-neoplastic immune response, and genetically arming viruses with cytokines such as IL-12. Oncolytic viral clinical outcomes are sought after, particularly in more advanced cancers. The effectiveness and safety profile of the oncolytic virus in clinical studies with or without the combination of standard treatment (chemotherapy, radiotherapy, or primary excision) has been assessed using response evaluation criteria in solid tumors (RECIST). This review will comprehensively outline the most recent clinical applications and provide the results from various phases of clinical trials in a variety of cancers in the latest published literature.

γδ-Enriched CAR-T cell therapy for bone metastatic castrate-resistant prostate cancer

Immune checkpoint blockade has been largely unsuccessful for the treatment of bone metastatic castrate-resistant prostate cancer (mCRPC). Here, we report a combinatorial strategy to treat mCRPC using γδ-enriched chimeric antigen receptor (CAR) T cells and zoledronate (ZOL). In a preclinical murine model of bone mCRPC, γδ CAR-T cells targeting prostate stem cell antigen (PSCA) induced a rapid and significant regression of established tumors, combined with increased survival and reduced cancer-associated bone disease. Pretreatment with ZOL, a U.S. Food and Drug Administration-approved bisphosphonate prescribed to mitigate pathological fracture in mCRPC patients, resulted in CAR-independent activation of γδ CAR-T cells, increased cytokine secretion, and enhanced antitumor efficacy. These data show that the activity of the endogenous Vγ9Vδ2 T cell receptor is preserved in CAR-T cells, allowing for dual-receptor recognition of tumor cells. Collectively, our findings support the use of γδ CAR-T cell therapy for mCRPC treatment.

Current status and progress of the development of prostate cancer vaccines

At present, common treatments of prostate cancer mainly include surgery, radiotherapy, chemotherapy and hormone therapy. However, patients have high recurrence rate after treatment, and are prone to castration-resistant prostate cancer. Tumor vaccine is based on tumor specific antigen (TSA) and tumor associated antigen (TAA) to activate specific immune response of the body to cancer cells. With continuous maturity of tumor vaccine technology, different forms of prostate cancer vaccines have been developed, such as cellular vaccines, extracellular-based anti-tumor vaccines, polypeptide vaccines, and nucleic acid vaccines. In this review, we summarize current status and progress in the development of prostate cancer vaccines.

Advances in cancer vaccines for immunotherapy of prostate cancer

Prostate cancer is currently one of the most common malignancies that endanger the lives and health of elderly men. In recent years, immunotherapy, which exploits the activation of anti-cancer host immune cells to accomplish tumor-killing effects, has emerged as a new study avenue in the treatment of prostate cancer. As an important component of immunotherapy, cancer vaccines have a unique position in the precision treatment of malignant tumors. Monocyte cell vaccines, dendritic cell vaccines, viral vaccines, peptide vaccines, and DNA/mRNA vaccines are the most often used prostate cancer vaccines. Among them, Sipuleucel-T, as a monocyte cell-based cancer vaccine, is the only FDA-approved therapeutic vaccine for prostate cancer, and has a unique position and role in advancing the development of immunotherapy for prostate cancer. However, due to its own limitations, Sipuleucel-T has not been widely adopted. Meanwhile, owing to the complexity of immunotherapy and the specificity of prostate cancer, the remaining prostate cancer vaccines have not shown good clinical benefit in large randomized phase II and phase III trials, and further in-depth studies are still needed.

Metastatic Prostate Cancer-A Review of Current Treatment Options and Promising New Approaches

Androgen deprivation therapy (ADT) alone has been the standard of care for many years in men with metastatic prostate cancer. Due to the limited survival under this monotherapy, many new treatment options have been developed in the last few years. Regarding hormone-sensitive prostate cancer, combination therapies of two or three agents of ADT, androgen receptor signaling inhibitors (ARSI) and chemotherapy have been established and led to a significant benefit in overall survival. Additionally, in patients with metastatic castration-resistant prostate cancer, there are many new therapeutic approaches. Chemotherapy alone has been the standard of care in this situation. In the last years, some new therapeutic options have been developed, which led to an improved survival after progression under chemotherapy. These therapies include ARSI, PARP inhibitors and Lu-PSMA radioligand therapy. The use of a bispecific T-cell engager (BiTE) in this setting is a new promising therapeutic approach, which has not been established as standard of care yet. The role of immunotherapy in prostate cancer is still under investigation. Overall, many new treatment options make prostate cancer therapy a challenging and promising field.

LG. Phase II Trial of Pembrolizumab and Anti-CD3 x Anti-HER2 Bispecific Antibody-Armed Activated T Cells in Metastatic Castration-Resistant Prostate Cancer

PURPOSE

A phase II study was conducted to evaluate the safety and efficacy of the combination of HER2 bispecific antibody (HER2Bi)-armed activated T cells (HER2 BAT) and programmed death 1 inhibitor, pembrolizumab.

PATIENTS AND METHODS

Patients with metastatic castration-resistant prostate cancer (mCRPC) with 0 to 1 performance status and normal liver, kidney, and marrow function, pre- or post-docetaxel chemotherapy were eligible. Primary endpoint was 6-month progression-free survival (PFS). Peripheral blood mononuclear cells were obtained by a single apheresis, shipped to University of Virginia, activated with OKT3 and expanded for 14 days in IL2, harvested, and armed with HER2Bi and cryopreserved. HER2 BATs were infused twice weekly for 4 weeks and pembrolizumab was administered every 21 days for a maximum duration of 6 months starting 1 to 3 weeks prior to HER2 BATs infusion.

RESULTS

Fourteen patients were enrolled with a median age of 69 (range 57-82 years) and median PSA of 143.4 (range 8.2-4210 ng/dL). Two patients had peritoneal metastases, 1 had lymph node (LN) only metastases and 11 had bone metastases of which 7 had bone and LN metastases. All were pretreated with androgen receptor axis targeted agents and 7 (50%) had prior docetaxel chemotherapy. The toxicities were grade1-2 infusion reactions with fever, chills, headaches, nausea and/or myalgias. Primary endpoint of 6 month PFS was achieved in 5 of 14 patients (38.5%; 95% confidence interval, 19.5%-76.5%). Median PFS was 5 months and median survival was 31.6 months.

CONCLUSIONS

The safety and promising efficacy makes this combination worthy of future investigation in mCRPC.

Progression in immunotherapy for advanced prostate cancer

Prostate cancer is one of the most common malignant cancers of the male genitourinary system and has high morbidity and mortality. Currently, treatment modalities for localized prostate cancer focus mainly on radical prostatectomy or radical radiation therapy. Some patients still experience disease recurrence or progression after these treatments, while others are already at an advanced stage or have metastases at the time of diagnosis. With the continuous development and progress of medicine in recent years, immunotherapy has become a revolutionary cancer treatment, and has achieved remarkable accomplishments in the treatment of hematologic malignancies. A variety of immunotherapies have also appeared in the field of advanced prostate cancer treatment, including therapeutic vaccines and immune checkpoint therapies. Despite the discrepancy between the results of some immunotherapy studies, immunotherapy for prostate cancer has shown some initial success, especially in combination immunotherapies. Currently, immunotherapy is mainly used in advanced prostate cancer, especially in patients with metastatic castration-resistant prostate cancer. However, with the development of more clinical trials of immunotherapy, more evidence will be provided supporting the rational application of immunotherapy in the future.

A Brief Overview of Cancer Vaccines

ABSTRACT

Vaccine strategies for cancer differ from infectious disease in focusing mainly on clearing rather than preventing disease. Here we survey general vaccine strategies and combination therapy concepts being investigated for cancer treatment, with a focus on tumor antigens rather than cancer-inducing viruses or microorganisms. Many tumor antigens are "altered-self" and tend to arouse weaker immune responses than "foreign" antigens expressed by infectious agents. Further, unlike an infectious disease patient, a cancer patient's immune system is damaged, suppressed, or senescent and mainly tolerant of their disease. Thus, vaccine efficacy in a cancer patient will rely upon adjuvant or combination treatments that correct the inflammatory tumor microenvironment and degrade tumoral immunosuppression that dominates patient immunity. This brief overview is aimed at new researchers in cancer immunology seeking an overview of vaccine concepts to eradicate malignancy by provoking a selective immune attack.

Knowledge mapping and current trends of immunotherapy for prostate cancer: A bibliometric study

BACKGROUND

Prostate cancer (PCa) is the second most common malignancy in men worldwide. Growing evidence substantiates the important role of immunotherapy in human tumors. Given that immunotherapy is often unsatisfactory on PCa, many studies have been conducted on PCa immunotherapy to improve treatment efficacy. However, no relevant bibliometric study of PCa immunotherapy has hitherto been reported. A bibliometric analysis was performed to evaluate the global scientific production of PCa immunotherapy research and characterize the development trends for future studies in this article.

METHODS

The publications related to PCa immunotherapy were extracted from the Web of Science Core Collection. The contribution and co-occurrence relationships of countries/regions, institutions, journals, references, authors, and keywords were assessed and visualized by VOSviewer and CiteSpace to identify research hotspots and potential future trends.

RESULTS

A total of 3,583 publications related to PCa immunotherapy from 1999 to 2021 were collected. The results of annual publications and citations exhibited a steady increase over the past 22 years. The National Cancer Institute in the USA published far more papers during the study than any institute. Accordingly, the USA had the most publications (n = 1,954, 54.54%). Gulley, James L. had the most number of published papers, and Small, Eric J. was the most co-cited authors in this field. Cancer Immunology Immunotherapy was the most productive journal, with 145 publications on PCa immunotherapy. Keyword cluster and keyword burst analyses showed that research in PCa immunotherapy shifted from "t cell infiltration" and "sipuleucel t" to "immune checkpoint inhibitor", "CTLA-4", and "PD-L1 expression".

CONCLUSION

PCa immunotherapy has attracted much attention, reflected by the increasing number of annual publications and citations. Much emphasis has been placed on exploring the complex immunogenicity and tumor microenvironment for PCa and identifying the patient population who can benefit from immunotherapy. Combining immune checkpoint inhibitors with other therapeutic options and cancer vaccines represents the future development trends in PCa immunotherapy.

Oncolyic Virotherapy for Prostate Cancer: Lighting a Fire in Winter

As the most common cancer of the genitourinary system, prostate cancer (PCa) is a global men's health problem whose treatments are an urgent research issue. Treatment options for PCa include active surveillance (AS), surgery, endocrine therapy, chemotherapy, radiation therapy, immunotherapy, etc. However, as the cancer progresses, the effectiveness of treatment options gradually decreases, especially in metastatic castration-resistant prostate cancer (mCRPC), for which there are fewer therapeutic options and which have a shorter survival period and worse prognosis. For this reason, oncolytic viral therapy (PV), with its exceptional properties of selective tumor killing, relatively good safety in humans, and potential for transgenic delivery, has attracted increasing attention as a new form of anti-tumor strategy for PCa. There is growing evidence that OV not only kills tumor cells directly by lysis but can also activate anticancer immunity by acting on the tumor microenvironment (TME), thereby preventing tumor growth. In fact, evidence of the efficacy of this strategy has been observed since the late 19th century. However, subsequently, interest waned. The renewed interest in this therapy was due to advances in biotechnological methods and innovations at the end of the 20th century, which was also the beginning of PCa therapy with OV. Moreover, in combination with chemotherapy, radiotherapy, gene therapy or immunotherapy, OV viruses can have a wide range of applications and can provide an effective therapeutic result in the treatment of PCa.

mRNA vaccine with unmodified uridine induces robust type I interferon-dependent anti-tumor immunity in a melanoma model

An mRNA with unmodified nucleosides induces type I interferons (IFN-I) through the stimulation of innate immune sensors. Whether IFN-I induced by mRNA vaccine is crucial for anti-tumor immune response remains to be elucidated. In this study, we investigated the immunogenicity and anti-tumor responses of mRNA encoding tumor antigens with different degrees of N1-methylpseudouridine (m1Ψ) modification in B16 melanoma model. Our results demonstrated that ovalbumin (OVA) encoding mRNA formulated in a lipid nanoparticle (OVA-LNP) induced substantial IFN-I production and the maturation of dendritic cells (DCs) with negative correlation with increasing percentages of m1Ψ modification. In B16-OVA murine melanoma model, unmodified OVA-LNP significantly reduced tumor growth and prolonged survival, compared to OVA-LNP with m1Ψ modification. This robust anti-tumor effect correlated with the increase in intratumoral CD40⁺ DCs and the frequency of granzyme B⁺/IFN-γ⁺/TNF-α⁺ polyfunctional OVA peptide-specific CD8⁺ T cells. Blocking type I IFN receptor completely reversed the anti-tumor immunity of unmodified mRNA-OVA reflected in a significant decrease in OVA-specific IFN-γ secreting T cells and enrichment of PD-1⁺ tumor-infiltrating T cells. The robust anti-tumor effect of unmodified OVA-LNP was also observed in the lung metastatic tumor model. Finally, this mRNA vaccine was tested using B16 melanoma neoantigens (Pbk-Actn4) which resulted in delayed tumor growth. Taken together, our findings demonstrated that an unmodified mRNA vaccine induces IFN-I production or the downstream signaling cascades which plays a crucial role in inducing robust anti-tumor T cell response for controlling tumor growth and metastasis.

Prostate Cancer Tumor Stroma: Responsibility in Tumor Biology, Diagnosis and Treatment

Simple Summary

The crosstalk between prostate stroma and its epithelium is essential to tissue homeostasis. Likewise, reciprocal signaling between tumor cells and the stromal compartment is required in tumor progression to facilitate or stimulate key processes such as cell proliferation and invasion. The aim of the present work was to review the current state of knowledge on the significance of tumor stroma in the genesis, progression and therapeutic response of prostate carcinoma. Additionally, we addressed the future therapeutic opportunities.

Abstract

Prostate cancer (PCa) is a common cancer among males globally, and its occurrence is growing worldwide. Clinical decisions about the combination of therapies are becoming highly relevant. However, this is a heterogeneous disease, ranging widely in prognosis. Therefore, new approaches are needed based on tumor biology, from which further prognostic assessments can be established and complementary strategies can be identified. The knowledge of both the morphological structure and functional biology of the PCa stroma compartment can provide new diagnostic, prognostic or therapeutic possibilities. In the present review, we analyzed the aspects related to the tumor stromal component (both acellular and cellular) in PCa, their influence on tumor behavior and the therapeutic response and their consideration as a new therapeutic target.

Developing New Treatment Options for Castration-Resistant Prostate Cancer and Recurrent Disease

Prostate cancer (PCa) is a major diagnosed cancer among men globally, and about 20% of patients develop metastatic prostate cancer (mPCa) in the initial diagnosis. PCa is a typical androgen-dependent disease; thus, hormonal therapy is commonly used as a standard care for mPCa by inhibiting androgen receptor (AR) activities, or androgen metabolism. Inevitably, almost all PCa will acquire resistance and become castration-resistant PCa (CRPC) that is associated with AR gene mutations or amplification, the presence of AR variants, loss of AR expression toward neuroendocrine phenotype, or other hormonal receptors. Treating CRPC poses a great challenge to clinicians. Research efforts in the last decade have come up with several new anti-androgen agents to prolong overall survival of CRPC patients. In addition, many potential targeting agents have been at the stage of being able to translate many preclinical discoveries into clinical practices. At this juncture, it is important to highlight the emerging strategies including small-molecule inhibitors to AR variants, DNA repair enzymes, cell survival pathway, neuroendocrine differentiation pathway, radiotherapy, CRPC-specific theranostics and immune therapy that are underway or have recently been completed.

Outcome of 177 Lu-PSMA Radionuclide Treatment in Advanced Prostate Cancer and Its Association With Clinical Parameters : A Single-Center Experience

PURPOSE

This study was set out to analyze the efficacy and safety of 177 Lu-PSMA-617 (LuPSMA) treatment in metastatic castration-resistant prostate cancer (mCRPC) patients.

PATIENTS AND METHODS

Progressive mCRPC patients who received at least 1 cycle of LuPSMA therapy were evaluated retrospectively. Demographic, clinic, and histopathological data were documented. Treatment efficacy was determined based on biochemical response criteria (Prostate Cancer Clinical Trial Working Group 3), and toxicity rates were defined based on CTCAE v4.03. The prognostic significance of laboratory/clinical data and 68 Ga-PSMA PET/CT quantitative results were analyzed using SPSS Version 24.0.

RESULTS

One hundred patients (median prostate-specific antigen [PSA] level, 75.7 ng/mL) who met the eligibility criteria were identified. The median number of cycles received per patient was 3 (range, 1-9). After the first cycles of LuPSMA, biochemical partial response, biochemical stable disease, and biochemical progressive disease were observed in 31%, 36%, and 33% of patients, respectively. Any PSA decline was determined in 60% of patients. After the fourth cycle of treatment, biochemical partial response, biochemical stable disease, and biochemical progressive disease were defined in 48%, 26%, and 26% of patients, respectively. The median overall survival (OS) from the first cycle of LuPSMA was 14 months. Patients who had any PSA response after the first cycle had significantly longer OS than nonresponders (median OS: 17 vs 9 months; P ≤ 0.001). Total PSMA-derived tumor volume ( P = 0.004), total PSMA activity per lesion ( P = 0.01), PSA ( P = 0.007), alkaline phosphatase ( P = 0.002), lactate dehydrogenase ( P < 0.001), and hemoglobin ( P < 0.001) were significant prognostic factors for OS in univariate Cox regression analysis.

CONCLUSIONS

LuPSMA therapy is a favorable treatment for mCRPC with remarkable therapeutic efficacy and low toxicity rates, even in progressive disease under standard therapies. Baseline PSMA-based tumor burden, PSA, alkaline phosphatase, lactate dehydrogenase, and hemoglobin were significant predictors of OS and can be useful for selection of the best candidate for LuPSMA therapy.

Emerging Biomarker-Guided Therapies in Prostate Cancer

Prostate cancer remains one of the leading causes of cancer death in men worldwide. In the past decade, several new treatments for advanced prostate cancer have been approved. With a wide variety of available drugs, including cytotoxic agents, androgen receptor axis-targeted therapies, and alpha-emitting radiation therapy, identifying their optimal sequencing remains a challenge. Progress in the understanding of the biology of prostate cancer has provided an opportunity for a more refined and personalized treatment selection process. With the advancement of molecular sequencing techniques, genomic precision through the identification of potential treatment targets and predictive biomarkers has been rapidly evolving. In this review, we discussed biomarker-driven treatments for advanced prostate cancer. First, we presented predictive biomarkers for established, global standard treatments for advanced diseases, such as chemotherapy and androgen receptor axis-targeted agents. We also discussed targeted agents with recent approval for special populations, such as poly ADP ribose polymerase (PARP) inhibitors in patients with metastatic castrate-resistant prostate cancer with homologous recombination repair-deficient tumors, pembrolizumab in patients with high levels of microsatellite instability or high tumor mutational burden, and prostate-specific membrane antigen (PSMA) directed radioligand theragnostic treatment for PSMA expressing tumors. Additionally, we discussed evolving treatments, such as cancer vaccines, chimeric antigen receptor T-cells (CAR-T), Bispecific T-cell engagers (BiTEs), other targeted agents such as AKT inhibitors, and various combination treatments. In summary, advances in molecular genetics have begun to propel personalized medicine forward in the management of advanced prostate cancer, allowing for a more precise, biomarker-driven treatment selection with the goal of improving overall efficacy.

Harnessing the Immune System with Cancer Vaccines: From Prevention to Therapeutics

Prophylactic vaccination against infectious diseases is one of the most successful public health measures of our lifetime. More recently, therapeutic vaccination against established diseases such as cancer has proven to be more challenging. In the host, cancer cells evade immunologic regulation by multiple means, including altering the antigens expressed on their cell surface or recruiting inflammatory cells that repress immune surveillance. Nevertheless, recent clinical data suggest that two classes of antigens show efficacy for the development of anticancer vaccines: tumor-associated antigens and neoantigens. In addition, many different vaccines derived from antigens based on cellular, peptide/protein, and genomic components are in development to establish their efficacy in cancer therapy. Some vaccines have shown promising results, which may lead to favorable outcomes when combined with standard therapeutic approaches. This review provides an overview of the innate and adaptive immune systems, their interactions with cancer cells, and the development of various different vaccines for use in anticancer therapeutics.

Development of Cancer Immunotherapies

Cancer immunotherapy, or the utilization of components of the immune system to target and eliminate cancer, has become a highly active area of research in the past several decades and a common treatment strategy for several cancer types. The concept of harnessing the immune system for this purpose originated over 100 years ago when a physician by the name of William Coley successfully treated several of his cancer patients with a combination of live and attenuated bacteria, later known as "Coley's Toxins", after observing a subset of prior patients enter remission following their diagnosis with the common bacterial infection, erysipelas. However, it was not until late in the twentieth century that cancer immunotherapies were developed for widespread use, thereby transforming the treatment landscape of numerous cancer types. Pivotal studies elucidating molecular and cellular functions of immune cells, such as the discovery of IL-2 and production of monoclonal antibodies, fostered the development of novel techniques for studying the immune system and ultimately the development and approval of several cancer immunotherapies by the United States Food and Drug Association in the 1980s and 1990s, including the tuberculosis vaccine-Bacillus Calmette-Guérin, IL-2, and the CD20-targeting monoclonal antibody. Approval of the first therapeutic cancer vaccine, Sipuleucel-T, for the treatment of metastatic castration-resistant prostate cancer and the groundbreaking success and approval of immune checkpoint inhibitors and chimeric antigen receptor T cell therapy in the last decade, have driven an explosion of interest in and pursuit of novel cancer immunotherapy strategies. A broad range of modalities ranging from antibodies to adoptive T cell therapies is under investigation for the generalized treatment of a broad spectrum of cancers as well as personalized medicine. This chapter will focus on the recent advances, current strategies, and future outlook of immunotherapy development for the treatment of cancer.

Emerging Strategies in TCR-Engineered T Cells

Immunotherapy of cancer has made tremendous progress in recent years, as demonstrated by the remarkable clinical responses obtained from adoptive cell transfer (ACT) of patient-derived tumor infiltrating lymphocytes, chimeric antigen receptor (CAR)-modified T cells (CAR-T) and T cell receptor (TCR)-engineered T cells (TCR-T). TCR-T uses specific TCRS optimized for tumor engagement and can recognize epitopes derived from both cell-surface and intracellular targets, including tumor-associated antigens, cancer germline antigens, viral oncoproteins, and tumor-specific neoantigens (neoAgs) that are largely sequestered in the cytoplasm and nucleus of tumor cells. Moreover, as TCRS are naturally developed for sensitive antigen detection, they are able to recognize epitopes at far lower concentrations than required for CAR-T activation. Therefore, TCR-T holds great promise for the treatment of human cancers. In this focused review, we summarize basic, translational, and clinical insights into the challenges and opportunities of TCR-T. We review emerging strategies used in current ACT, point out limitations, and propose possible solutions. We highlight the importance of targeting tumor-specific neoAgs and outline a strategy of combining neoAg vaccines, checkpoint blockade therapy, and adoptive transfer of neoAg-specific TCR-T to produce a truly tumor-specific therapy, which is able to penetrate into solid tumors and resist the immunosuppressive tumor microenvironment. We believe such a combination approach should lead to a significant improvement in cancer immunotherapies, especially for solid tumors, and may provide a general strategy for the eradication of multiple cancers.

Efficacy and Safety of Autologous Dendritic Cell-Based Immunotherapy, Docetaxel, and Prednisone vs Placebo in Patients With Metastatic Castration-Resistant Prostate Cancer: The VIABLE Phase 3 Randomized Clinical Trial

IMPORTANCE

DCVAC/PCa is an active cellular immunotherapy designed to initiate an immune response against prostate cancer.

OBJECTIVE

To evaluate the efficacy and safety of DCVAC/PCa plus chemotherapy followed by DCVAC/PCa maintenance treatment in patients with metastatic castration-resistant prostate cancer (mCRPC).

DESIGN, SETTING, AND PARTICIPANTS

The VIABLE double-blind, parallel-group, placebo-controlled, phase 3 randomized clinical trial enrolled patients with mCRPC among 177 hospital clinics in the US and Europe between June 2014 and November 2017. Data analyses were performed from December 2019 to July 2020.

INTERVENTIONS

Eligible patients were randomized (2:1) to receive DCVAC/PCa (add-on and maintenance) or placebo, both in combination with chemotherapy (docetaxel plus prednisone). The stratification was applied according to geographical region (US or non-US), prior therapy (abiraterone, enzalutamide, or neither), and Eastern Cooperative Oncology Group performance status (0-1 or 2). DCVAC/PCa or placebo was administered subcutaneously every 3 to 4 weeks (up to 15 doses).

MAIN OUTCOMES AND MEASURES

The primary outcome was overall survival (OS), defined as the time from randomization until death due to any cause, in all randomized patients. Survival was compared using 2-sided log-rank test stratified by geographical region, prior therapy with abiraterone and/or enzalutamide, and Eastern Cooperative Oncology Group performance status.

RESULTS

A total of 1182 men with mCRPC (median [range] age, 68 [46-89] years) were randomized to receive DCVAC/PCa (n = 787) or placebo (n = 395). Of these, 610 (81.8%) started DCVAC/PCa, and 376 (98.4%) started placebo. There was no difference in OS between the DCVAC/PCa and placebo groups in all randomized patients (median OS, 23.9 months [95% CI, 21.6-25.3] vs 24.3 months [95% CI, 22.6-26.0]; hazard ratio, 1.04; 95% CI, 0.90-1.21; P = .60). No differences in the secondary efficacy end points (radiological progression-free survival, time to prostate-specific antigen progression, or skeletal-related events) were observed. Treatment-emergent adverse events related to DCVAC/PCa or placebo occurred in 69 of 749 (9.2%) and 48 of 379 (12.7%) patients, respectively. The most common treatment-emergent adverse events (DCVAC/PCa [n = 749] vs placebo [n = 379]) were fatigue (271 [36.2%] vs 152 [40.1%]), alopecia (222 [29.6%] vs 130 [34.3%]), and diarrhea (206 [27.5%] vs 117 [30.9%]).

CONCLUSIONS AND RELEVANCE

In this phase 3 randomized clinical trial, DCVAC/PCa combined with docetaxel plus prednisone and continued as maintenance treatment did not extend OS in patients with mCRPC and was well tolerated.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02111577.

Phase 2 trial of T-cell activation using MVI-816 and pembrolizumab in patients with metastatic, castration-resistant prostate cancer (mCRPC)

Background

We previously reported a trial using a DNA vaccine encoding prostatic acid phosphatase (MVI-816, pTVG-HP), given over 12 weeks concurrently or sequentially with pembrolizumab, in patients with mCRPC. We report the final analysis of this trial following two additional treatment arms in which patients with mCRPC continued concurrent treatment until progression.

Materials and methods

Patients with mCRPC were treated with MVI-816 and pembrolizumab every 3 weeks (arm 3, n=20) or MVI-816 every 2 weeks and pembrolizumab every 4 weeks (arm 4, n=20). The primary objectives were safety, 6-month progression-free survival (PFS), median time to radiographic progression, and objective response rates. Secondary objectives included immunological evaluations.

Results

In 25 patients with measurable disease, there were no complete response and one confirmed partial response in a patient who subsequently found to have an MSI^hi tumor. 4/40 patients (10%) had a prostate-specific antigen decline >50%. The estimated overall radiographic PFS rate at 6 months was 47.2% (44.4% arm 3, 61.5% arm 4). Accounting for all off-study events, overall median time on treatment was 5.6 months (95% CI: 5.4 to 10.8 months), 5.6 months for arm 3 and 8.1 months for arm 4 (p=0.64). Thirty-two per cent of patients remained on trial beyond 6 months without progression. Median overall survival was 22.9 (95% CI: 16.2 to 25.6) months. One grade 4 event (hyperglycemia) was observed. Immune-related adverse events (irAEs) >grade 1 were observed in 42% of patients overall. Interferon-γ and/or granzyme B immune response to prostatic acid phosphatase was detected in 2/20 patients in arm 3 and 6/20 patients in arm 4. Plasma cytokines associated with immune activation and CD8+ T-cell recruitment were augmented at weeks 6 and 12. The development of irAE was significantly associated with a prolonged time on treatment (HR=0.42, p=0.003). Baseline DNA homologous recombination repair mutations were not associated with longer time to progression.

Conclusions

Findings here demonstrate that combining programmed cell death 1 blockade with MVI-816 is safe, can augment tumor-specific T cells, and can result in a favorable 6-month disease control rate. Correlative studies suggest T-cell activation by vaccination is critical to the mechanism of action of this combination. Future randomized clinical trials are needed to validate these findings.

Trial registration number

NCT02499835.

Genetically modified cancer vaccines: Current status and future prospects

Vaccines can stimulate the immune system to protect individuals from infectious diseases. Moreover, vaccines have also been applied to the prevention and treatment of cancers. Due to advances in genetic engineering technology, cancer vaccines could be genetically modified to increase antitumor efficacy. Various genes could be inserted into cells to boost the immune response, such as cytokines, T cell costimulatory molecules, tumor-associated antigens, and tumor-specific antigens. Genetically modified cancer vaccines utilize innate and adaptive immune responses to induce durable antineoplastic capacity and prevent the recurrence. This review will discuss the major approaches used to develop genetically modified cancer vaccines and explore recent advances to increase the understanding of engineered cancer vaccines.

Immunotherapy in Advanced Prostate Cancer-Light at the End of the Tunnel?

Immunotherapeutic treatment approaches are now an integral part of the treatment of many solid tumors. However, attempts to integrate immunotherapy into the treatment of prostate cancer have been disappointing so far. This is due to a highly immunosuppressive, "cold" tumor microenvironment, which is characterized, for example, by the absence of cytotoxic T cells, an increased number of myeloid-derived suppressor cells or regulatory T cells, a decreased number of tumor antigens, or a defect in antigen presentation. The consequence is a reduced efficacy of many established immunotherapeutic treatments such as checkpoint inhibitors. However, a growing understanding of the underlying mechanisms of tumor-immune system interactions raises hopes that immunotherapeutic strategies can be optimized in the future. The aim of this review is to provide an overview of the current status and future directions of immunotherapy development in prostate cancer. Background information on immune response and tumor microenvironment will help to better understand current therapeutic strategies under preclinical and clinical development.