Recent Advances in Cancer Immunotherapy with a Focus on FDA-Approved Vaccines and Neoantigen-Based Vaccines

Pediatric gliomas immunity challenges and immunotherapy advances

Pediatric gliomas, the most frequent brain tumors in children, are characterized by heterogeneity and a unique tumor immune microenvironment. They are categorized into different subtypes, including low-grade gliomas like pilocytic astrocytomas and high-grade gliomas such as diffuse midline gliomas and diffuse intrinsic pontine gliomas, each exhibiting distinct immunological profiles. The tumor immune microenvironment in pediatric gliomas is shaped by cellular and non-cellular components, including immune cells, cytokines, and the extracellular matrix, involved in tumor progression, immune evasion, and response to therapy. While pediatric low-grade gliomas often display an immunosuppressed microenvironment, high-grade gliomas are characterized by complex immune infiltrates and intricate immunosuppressive mechanisms. The blood-brain barrier further obscures immune cell recruitment and therapeutic delivery. Despite advances in understanding adult gliomas, the immunobiology of pediatric tumors is poorly investigated, with limited data on the interactions between glioma cells and immune populations such as T and natural killer cells, as well as tumor-associated macrophages. Herein, we provide an update of the current knowledge on tumor immune microenvironment interactions in pediatric gliomas, highlighting the immunosuppressive mechanisms and emerging immunotherapeutic strategies aiming at overcoming these barriers to improve clinical outcomes for affected children.

Immunogenicity and Safety Profile of Two Adjuvanted-PD-L1-Based Vaccine Candidates in Mice, Rats, Rabbits, and Cynomolgus Monkeys

BACKGROUND

The therapeutic blockade of the PD1/PD-L1 axis with monoclonal antibodies has led to a breakthrough in cancer treatment, as it plays a key role in the immune evasion of tumors. Nevertheless, treating patients with cancer with vaccines that stimulate a targeted immune response is another attractive approach for which few side effects have been observed in combination immunotherapy clinical trials. In this sense, our group has recently developed a therapeutic cancer vaccine candidate called PKPD-L1Vac which contains as an antigen the extracellular domain of human PD-L1 fused to a 47 amino-terminal, part of the LpdA gene of N. meningitides, which is produced in E. coli. The investigation of potential toxicities associated with PD-L1 blockade by a new therapy in preclinical studies is critical to optimizing the efficacy and safety of that new therapy.

METHODS

Here, we describe immunogenicity and preliminary safety studies in mice, rats, rabbits, and non-human primates that make use of a 200 μg dose of PKPD-L1 in combination with VSSPs or alum phosphate to contribute to the assessment of potential adverse events that are relevant to the future clinical development program of this novel candidate.

RESULTS

The administration of PKPD-L1Vac to the four species at the doses studied was immunogenic and did not result in behavioral, clinical, hematological, or serum biochemical changes.

CONCLUSIONS

Therefore, PKPD-L1Vac could be considered suitable for further complex toxicological studies and the way for its clinical evaluation in humans has been opened.

Humanized Mouse Models for Immuno-Oncology Research: A Review and Implications in Lung Cancer Research

Cancer immunotherapy has brought significant clinical benefits to patients with cancer, including those with lung cancer. Patient-derived tumor xenograft mouse models have become the preferred animal model for translational cancer research and preclinical studies. Given the unmet need for improved predictive models in immuno-oncology, humanized mouse models which are co-engrafted with both human tumors and immune system components have been used to investigate novel immunotherapeutics. These models have similarly been used to predict immune-related adverse events and to develop predictive biomarkers. This review summarizes key concepts related to humanized mouse models. We highlight the various approaches to generate them, factors that are critical to successfully establishing such models, their respective limitations, and considerations in model selection for preclinical lung cancer immuno-oncology research and therapeutic studies.

Vaccine-Based Immunotherapy for Oropharyngeal and Nasopharyngeal Cancers

Viral infections such as human papillomavirus (HPV) and Epstein-Barr virus (EBV) play a critical role in the onset of oropharyngeal (OPC) and nasopharyngeal cancer (NPC), respectively. Despite advancements in targeted therapies and immunotherapies, in the recurrent/metastatic setting, these tumors remain incurable diseases with poor prognosis. The development of therapeutic tumor vaccines, utilizing either neoantigens or oncoviral antigens, represents a promising addition to the cancer immunotherapy arsenal. Research on vaccine-based immunotherapy for OPC and NPC focuses on targeting viral antigens, particularly HPV E6/E7 and EBV EBNA1/LMP2. The potential for vaccine platforms, including peptide-based, DNA, RNA, and viral vector-based vaccines, to induce durable immune responses against viral antigens is reported. The early-phase clinical trials evaluating vaccine-based therapies for HPV-related OPC and EBV-related NPC revealed safety and preliminary signs of efficacy; however, further clinical trials are crucial for validation. This review provides an overview of the current landscape of vaccine-based strategies for HPV-related OPC and EBV-related NPC, discussing their biological mechanisms and immune processes involved in anti-HPV and anti-EBV vaccine treatments, with a particular focus on the immune factors that influence these therapies.

Immunotherapy in Recurrent Ovarian Cancer

BACKGROUND/OBJECTIVES

It remains challenging to treat recurrent ovarian cancer effectively as traditional interventions like chemotherapy and surgery have limited long-term efficacy, highlighting an urgent need for innovative approaches. Immunotherapy offers potential advantages in modulating the immune response against tumor cells and has emerged as a promising strategy in ovarian cancer management. This review discusses various immunotherapy modalities, including active and passive immune strategies, for recurrent ovarian cancer.

METHODS

We systematically reviewed recent immunotherapy advances for recurrent ovarian cancer, including the efficacy and mechanisms of single and dual immune checkpoint inhibitors, checkpoint inhibitor combinations with chemotherapy or radiotherapy, anti-angiogenic agents, PARP inhibitors, antibody-drug conjugates (ADC), tumor vaccines, and adoptive cell therapies (ACT). Additionally, we assessed emerging research on biomarkers predictive of immunotherapy responsiveness in ovarian cancer.

RESULTS

The findings indicate that immunotherapy, particularly combinations involving immune checkpoint inhibitors and other agents, demonstrates promising efficacy in recurrent ovarian cancer, with some therapies showing enhanced benefits in specific subtypes. The immune microenvironment in platinum-sensitive and -resistant cases exhibits distinct immunological profiles, influencing therapy outcomes. Several potential biomarkers have been identified, potentially aiding in patient stratification and treatment optimization.

CONCLUSIONS

Immunotherapy significantly advances recurrent ovarian cancer treatment, with various combinations potentially improving outcomes. Further research on predictive biomarkers and immune microenvironment characteristics is crucial for personalizing immunotherapy approaches and enhancing their efficacy in managing recurrent ovarian cancer.

Therapeutic advantage of combinatorial chimeric antigen receptor T cell and chemotherapies

Chimeric antigen receptor (CAR) T cell therapies have transformed outcomes for many patients with hematological malignancies. However, some patients do not respond to CAR T cell treatment, and adapting CAR T cells for treatment of solid and brain tumors has been met with many challenges, including a hostile tumor microenvironment and poor CAR T cell persistence. Thus, it is unlikely that CAR T cell therapy alone will be sufficient for consistent, complete tumor clearance across patients with cancer. Combinatorial therapies of CAR T cells and chemotherapeutics are a promising approach for overcoming this because chemotherapeutics could augment CAR T cells for improved antitumor activity or work in tandem with CAR T cells to clear tumors. Herein, we review efforts toward achieving successful CAR T cell and chemical drug combination therapies. We focus on combination therapies with approved chemotherapeutics because these will be more easily translated to the clinic but also review nonapproved chemotherapeutics and drug screens designed to reveal promising new CAR T cell and chemical drug combinations. Overall, this review highlights the promise of CAR T cell and chemotherapy combinations with a specific focus on how combinatorial therapy overcomes challenges faced by either monotherapy and supports the potential of this therapeutic strategy to improve outcomes for patients with cancer. SIGNIFICANCE STATEMENT: Improving currently available CAR T cell products via combinatorial therapy with chemotherapeutics has the potential to drastically expand the types of cancers and number of patients that could benefit from these therapies when neither alone has been sufficient to achieve tumor clearance. Herein, we provide a thorough review of the current efforts toward studying CAR T and chemotherapy combinatorial therapies and offer perspectives on optimal ways to identify new and effective combinations moving forward.

Cancer vaccines: an update on recent achievements and prospects for cancer therapy

Decades of basic and translational research have led to a momentum shift in dissecting the relationship between immune cells and cancer. This culminated in the emergence of breakthrough immunotherapies that paved the way for oncologists to manage certain hard-to-treat cancers. The application of high-throughput techniques of genomics, transcriptomics, and proteomics was conclusive in making and expediting the manufacturing process of cancer vaccines. Using the latest research technologies has also enabled scientists to interpret complex and multiomics data of the tumour mutanome, thus identifying new tumour-specific antigens to design new generations of cancer vaccines with high specificity and long-term efficacy. Furthermore, combinatorial regimens of cancer vaccines with immune checkpoint inhibitors have offered new therapeutic approaches and demonstrated impressive efficacy in cancer patients over the last few years. In the present review, we summarize the current state of cancer vaccines, including their potential therapeutic effects and the limitations that hinder their effectiveness. We highlight the current efforts to mitigate these limitations and highlight ongoing clinical trials. Finally, a special focus will be given to the latest milestones expected to transform the landscape of cancer therapy and nurture hope among cancer patients.

Personalized nanovaccines for treating solid cancer metastases

Cancer vaccines have garnered attention as a potential treatment for cancer metastases. Nevertheless, the clinical response rate to vaccines remains < 30%. Nanoparticles stabilize vaccines and improve antigen recognition and presentation, resulting in high tumor penetration or accumulation, effective co-distribution of drugs to the secondary lymphatic system, and adaptable antigen or adjuvant administration. Such vaccine-like nanomedicines have the ability to eradicate the primary tumors as well as to prevent or eliminate metastases. This review examines state-of-the-art nanocarriers developed to deliver tumor vaccines to metastases, including synthetic, semi-biogenic, and biogenic nanosystems. Moreover, it highlights the physical and pharmacological properties that enhance their anti-metastasis efficiency. This review also addresses the combination of nanovaccines with cancer immunotherapy to target various steps in the metastatic cascade, drawing insights from preclinical and clinical studies. The review concludes with a critical analysis of the challenges and frameworks linked to the clinical translation of cancer nanovaccines.

Vaccine-based therapeutic interventions in lung cancer management: A recent perspective

The incidence of lung cancer continues to grow globally, contributing to an ever-increasing load on healthcare systems. Emerging evidence has indicated lowered efficacy of conventional treatment strategies, such as chemotherapy, surgical interventions and radiotherapy, prompting the need for exploring alternative interventions. A growing focus on immunotherapy and the development of personalized medicine has paved the way for vaccine-based delivery in lung cancer. With various prominent targets such as CD8+T cells and PD-L1, immune-targeted, anti-cancer vaccines have been evaluated in both, pre-clinical and clinical settings, to improve therapeutic outcomes. However, there are a number of challenges that must be addressed, including the scalability of such delivery systems, heterogeneity of lung cancers, and long-term safety as well as efficacy. In addition to this, natural compounds, in combination with immunotherapy, have gained considerable research interest in recent times. This makes it necessary to explore their role in synergism with immune-targeted agents. The authors of this review aim to offer an overview of recent advances in our understanding of lung cancer pathogenesis, detection and management strategies, and the emergence of immunotherapy with a special focus on vaccine delivery. This finding is supported with evidence from testing in non-human and human models, showcasing promising results. Prospects for phytotherapy have also been discussed, in order to combat some pitfalls and limitations. Finally, the future perspectives of vaccine usage in lung cancer management have also been discussed, to offer a holistic perspective to readers, and to prompt further research in the domain.

Advancements in Immunotherapy for Breast Cancer: Mechanisms, Efficacy, and Future Directions

Breast cancer is a major global health challenge characterized by its diverse biological behavior and varying treatment responses. Traditional therapies, including surgery, radiation, chemotherapy, hormonal therapy, and targeted therapy, have significantly advanced breast cancer treatment but are often limited by issues such as resistance, side effects, and variable efficacy. Immunotherapy has emerged as a transformative approach, leveraging the body's immune system to target and eliminate cancer cells. This review provides a comprehensive overview of recent advancements in immunotherapy for breast cancer, detailing the mechanisms of various therapeutic strategies, including checkpoint inhibitors, monoclonal antibodies, cancer vaccines, adoptive cell therapy, and oncolytic virus therapy. We evaluate the efficacy of these approaches in different stages of breast cancer, highlighting successes and challenges encountered in clinical settings. The review also addresses the current limitations of immunotherapy, such as treatment-related adverse effects, resistance mechanisms, and issues of cost and accessibility. We discuss promising future directions, including emerging targets, combination therapies, and personalized medicine approaches. By integrating recent research and clinical trial data, this review aims to elucidate the potential of immunotherapy to revolutionize breast cancer treatment, offering insights into its future role in improving patient outcomes and shaping the landscape of oncological care.

Targeting metabolic pathways to counter cancer immunotherapy resistance

Immunotherapies have revolutionized the treatment of certain cancers, but challenges remain in overcoming immunotherapy resistance. Research shows that metabolic modulation of the tumor microenvironment can enhance antitumor immunity. Here, we discuss recent preclinical and clinical evidence for the efficacy of combining metabolic modifiers with immunotherapies. While this combination holds great promise, a few key areas must be addressed, which include identifying the effects of metabolic modifiers on immune cell metabolism, the putative biomarkers of therapeutic efficacy, the efficacy of modifiers on tumors harboring metabolic heterogeneity, and the potential development of resistance due to tumor reliance on alternative metabolic pathways. We propose solutions to these problems and posit that assessing these parameters is crucial for considering the potential of metabolic modifiers in sensitizing tumors to immunotherapies.

Glioblastoma Vaccines as Promising Immune-Therapeutics: Challenges and Current Status

Glioblastoma (GBM) is the most common and aggressive malignant brain tumor. Standard treatments including surgical resection, radiotherapy, and chemotherapy, have failed to significantly improve the prognosis of glioblastoma patients. Currently, immunotherapeutic approaches based on vaccines, chimeric antigen-receptor T-cells, checkpoint inhibitors, and oncolytic virotherapy are showing promising results in clinical trials. The combination of different immunotherapeutic approaches is proving satisfactory and promising. In view of the challenges of immunotherapy and the resistance of glioblastomas, the treatment of these tumors requires further efforts. In this review, we explore the obstacles that potentially influence the efficacy of the response to immunotherapy and that should be taken into account in clinical trials. This article provides a comprehensive review of vaccine therapy for glioblastoma. In addition, we identify the main biomarkers, including isocitrate dehydrogenase, epidermal growth factor receptor, and telomerase reverse transcriptase, known as potential immunotherapeutic targets in glioblastoma, as well as the current status of clinical trials. This paper also lists proposed solutions to overcome the obstacles facing immunotherapy in glioblastomas.

Current Progress in Vaccines against Merkel Cell Carcinoma: A Narrative Review and Update

Merkel cell carcinoma is a rare, aggressive skin cancer that mainly occurs in elderly and immunocompromised patients. Due to the success of immune checkpoint inhibition in MCC, the importance of immunotherapy and vaccines in MCC has increased in recent years. In this article, we aim to present the current progress and perspectives in the development of vaccines for this disease. Here, we summarize and discuss the current literature and ongoing clinical trials investigating vaccines against MCC. We identified 10 articles through a PubMed search investigating a vaccine against MCC. From the international clinical trial database Clinical.Trials.gov, we identified nine studies on vaccines for the management of MCC, of which seven are actively recruiting. Most of the identified studies investigating a vaccine against MCC are preclinical or phase 1/2 trials. The vaccine principles mainly included DNA- and (synthetic) peptide-based vaccines, but RNA-based vaccines, oncolytic viruses, and the combination of vaccines and immunotherapy are also under investigation for the treatment of MCC. Although the management of MCC is changing, when compared to times before the approval of immune checkpoint inhibitors, it will still take some time before the first MCC vaccine is ready for approval.

Emerging potential of immunopeptidomics by mass spectrometry in cancer immunotherapy

With significant advances in analytical technologies, research in the field of cancer immunotherapy, such as adoptive T cell therapy, cancer vaccine, and immune checkpoint blockade (ICB), is currently gaining tremendous momentum. Since the efficacy of cancer immunotherapy is recognized only by a minority of patients, more potent tumor-specific antigens (TSAs, also known as neoantigens) and predictive markers for treatment response are of great interest. In cancer immunity, immunopeptides, presented by human leukocyte antigen (HLA) class I, play a role as initiating mediators of immunogenicity. The latest advancement in the interdisciplinary multiomics approach has rapidly enlightened us about the identity of the "dark matter" of cancer and the associated immunopeptides. In this field, mass spectrometry (MS) is a viable option to select because of the naturally processed and actually presented TSA candidates in order to grasp the whole picture of the immunopeptidome. In the past few years the search space has been enlarged by the multiomics approach, the sensitivity of mass spectrometers has been improved, and deep/machine-learning-supported peptide search algorithms have taken immunopeptidomics to the next level. In this review, along with the introduction of key technical advancements in immunopeptidomics, the potential and further directions of immunopeptidomics will be reviewed from the perspective of cancer immunotherapy.

Are we getting closer to a successful neoantigen cancer vaccine?

Although significant advances in immunotherapy have revolutionized the treatment of many cancer types over the past decade, the field of vaccine therapy, an important component of cancer immunotherapy, despite decades-long intense efforts, is still transmitting signals of promises and awaiting strong data on efficacy to proceed with regulatory approval. The field of cancer vaccines faces standard challenges, such as tumor-induced immunosuppression, immune response in inhibitory tumor microenvironment (TME), intratumor heterogeneity (ITH), permanently evolving cancer mutational landscape leading to neoantigens, and less known obstacles: neoantigen gain/loss upon immunotherapy, the timing and speed of appearance of neoantigens and responding T cell clonotypes and possible involvement of immune interference/heterologous immunity, in the complex interplay between evolving tumor epitopes and the immune system. In this review, we discuss some key issues related to challenges hampering the development of cancer vaccines, along with the current approaches focusing on neoantigens. We summarize currently well-known ideas/rationales, thus revealing the need for alternative vaccine approaches. Such a discussion should stimulate vaccine researchers to apply out-of-box, unconventional thinking in search of new avenues to deal with critical, often yet unaddressed challenges on the road to a new generation of therapeutics and vaccines.

[Cell therapy in all its forms]

Immunotherapy strategies have revolutionized the management of a significant number of patients in recent years, whether they are undergoing treatment for hematologic malignancies or solid tumors. This therapeutic class is extensive, ranging from antibodies targeting immune checkpoint molecules to adoptive cell therapy strategies, including bispecific antibodies and anticancer vaccines. All these strategies are currently in active development. Adoptive cell therapy involves the infusion of normal or genetically modified immune cells into a patient with the aim of restoring strong antitumor immunity, primarily associated with the cytotoxicity of T lymphocytes. Currently, there are three major adoptive cell therapy strategies: allogeneic hematopoietic stem cell transplantation, CAR-T cell therapy, and TCR-T cell therapy. The objective of this article is to describe the mechanisms of action of these three strategies as well as their current advantages, limitations and constraints.