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.

Rational Design of an Epidermal Growth Factor Receptor Vaccine: Immunogenicity and Antitumor Research

The epidermal growth factor receptor (EGFR) is frequently overexpressed in a variety of human epithelial tumors, and its aberrant activation plays a pivotal role in promoting tumor growth, invasion, and metastasis. The clinically approved passive EGFR-related therapies have numerous limitations. Seven EGFR-ECD epitope peptides (EG1-7) were selected through bioinformatics epitope prediction tools including NetMHCpan-4.1, NetMHCIIpan-3.2, and IEDB Consensus (v2.18 and v2.22) and fused to the translocation domain of diphtheria toxin (DTT). The A549 tumor model was successfully established in a murine mouse model. The vaccine was formulated by combining the adjuvants Alum and CpG and subsequently assessed for its immunogenicity and anti-tumor efficacy. DTT-EG (3;5;6;7) vaccines elicited specific humoral and cellular immune responses and effectively suppressed tumor growth in both prophylactic and therapeutic mouse tumor models. The selected epitopes EG3 (HGAVRFSNNPALCNV145-159), EG5 (KDSLSINATNIKHFK346-360), EG6 (VKEITGFLLIQAWPE398-412), and EG7 (LCYANTINWKKLFGT469-483) were incorporated into vaccines for active immunization, representing a promising strategy for the treatment of tumors with overexpressed epidermal growth factor receptor (EGFR). The vaccine design and fusion method employed in this study demonstrate a viable approach toward the development of cancer vaccines.

The current therapeutic cancer vaccines landscape in non-small cell lung cancer

Currently, conventional immunotherapies for the treatment of non-small cell lung cancer (NSCLC) have low response rates and benefit only a minority of patients, particularly those with advanced disease, so novel therapeutic strategies are urgent deeded. Therapeutic cancer vaccines, a form of active immunotherapy, harness potential to activate the adaptive immune system against tumor cells via antigen cross-presentation. Cancer vaccines can establish enduring immune memory and guard against recurrences. Vaccine-induced tumor cell death prompts antigen epitope spreading, activating functional T cells and thereby sustaining a cancer-immunity cycle. The success of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rendered cancer vaccines a promising avenue, especially when combined with immunotherapy or chemoradiotherapy for NSCLC. This review delves into the intricate antitumor immune mechanisms underlying therapeutic cancer vaccines, enumerates the tumor antigen spectrum of NSCLC, discusses different cancer vaccines progress and summarizes relevant clinical trials. Additionally, we analyze the combination strategies, current limitations, and future prospects of cancer vaccines in NSCLC treatment, aiming to offer fresh insights for their clinical application in managing NSCLC. Overall, cancer vaccines offer promising potential for NSCLC treatment, particularly combining with chemoradiotherapy or immunotherapy could further improve survival in advanced patients. Exploring inhaled vaccines or prophylactic vaccines represents a crucial research avenue.

NitraTh epitope-based neoantigen vaccines for effective tumor immunotherapy

Neoantigen vaccines represent an emerging and promising strategy in the field of tumor immunotherapy. Despite their potential, designing an effective neoantigen vaccine remains a challenge due to the current limitations in predicting CD4+ T cell epitopes with high accuracy. Here, we introduce a novel approach to neoantigen vaccine design that does not rely on computational prediction of CD4+ T cell epitopes. Utilizing nitrated helper T cell epitope containing p-nitrophenylalanine, termed "NitraTh epitope," we have successfully engineered a series of tumor neoantigen vaccines capable of eliciting robust neoantigen-specific immune responses. With the help of NitraTh epitope, even mutations with low predicted affinity for MHC class I molecules were successfully induced to elicit neoantigen-specific responses. In H22 cell allograft and patient-derived xenograft (PDX) liver cancer mouse models, the NitraTh epitope-based neoantigen vaccines significantly suppressed tumor progression. More strikingly, through single-cell sequencing we found that the NitraTh epitope-based neoantigen vaccines regulate macrophage reprogramming and modulate macrophages to decrease the levels of the immunosuppressive molecule prostaglandin E2 (PGE2), which in turn reshapes the tumor immunosuppressive microenvironment. In summary, NitraTh epitope-based neoantigen vaccines possess the dual effects of potently activating neoantigen-specific immunity and alleviating immunosuppression, potentially providing a new paradigm for the design of tumor neoantigen vaccines.

TEDOVA: vaccine OSE2101 +/- pembrolizumab as maintenance in platinum-sensitive recurrent ovarian cancer

Ovarian cancer is a leading cause of death from gynecological cancers worldwide. Platinum-based chemotherapy provides the cornerstone of the medical management. In first line and subsequent relapses, maintenance strategies are offered to prolong intervals between lines of chemotherapy. Current maintenance options involve bevacizumab and poly ADP-ribose polymerase inhibitors, but these lines of therapy can only be used once in the disease course. Patients in first or second platinum sensitive relapse after poly ADP-ribose polymerase inhibitors and bevacizumab represent an area of unmet medical need. This academic sponsored, international Phase II randomized trial is evaluating the combination of a therapeutic cancer vaccine (OSE2101) with anti-PD1 (pembrolizumab) as maintenance therapy, in patients with platinum-sensitive recurrence regardless of number of prior lines and no progression after platinum-based chemotherapy.Clinical Trial Registration: NCT04713514 (ClinicalTrials.gov).

Lung cancer vaccination from concept to reality: A critical review of clinical trials and latest advances

Lung cancer is a highly lethal malignancy that poses a significant burden on public health worldwide. There have been numerous therapeutic approaches, among which cancer vaccines have emerged as a promising approach to harnessing the patient's immune system to induce long-lasting anti-tumor immunity. The current study aims to provide an overview of cancer vaccination in the context of lung cancer to establish a clearer landscape for lung cancer treatment. To provide a comprehensive review, we not only gathered the published studies of lung cancer vaccination and discussed their effectiveness and safety profile but also analyzed all the relevant clinical trials registered on www.clinicaltrials.gov until March 2024. We demonstrated all utilized vaccine platforms along with having a glance at novel technologies such as mRNA vaccines. The present review discussed the challenges and shortcomings of lung cancer vaccination, as well as the way they could be managed to pave the way for reaching the most optimized vaccine formulation.

An Adjuvanted Vaccine-Induced Pathogenesis Following Influenza Virus Infection

An incomplete Freund's adjuvant elicited an overt pathogenesis in vaccinated mice following the intranasal challenge of A/California/07/2009 (H1N1) virus despite the induction of a higher specific antibody titer than other adjuvanted formulations. Aluminum hydroxide adjuvants have not induced any pathogenic signs in a variety of formulations with glycolipids. A glycolipid, α-galactosyl ceramide, improved a stimulatory effect of distinct adjuvanted formulations on an anti-influenza A antibody response. In contrast to α-galactosyl ceramide, its synthetic analogue C34 was antagonistic toward a stimulatory effect of an aluminum hydroxide adjuvant on a specific antibody response. The aluminum hydroxide adjuvant alone could confer complete vaccine-induced protection against mortality as well as morbidity caused by a lethal challenge of the same strain of an influenza A virus. The research results indicated that adjuvants could reshape immune responses either to improve vaccine-induced immunity or to provoke an unexpected pathogenic consequence. On the basis of these observations, this research connotes the prominence to develop a precision adjuvant for innocuous vaccination aimed at generating a protective immunity without aberrant responses.

In silico designing of an epitope-based peptide vaccine cocktail against Nipah virus: an Indian population-based epidemiological study

Nipah virus, a zoonotic virus from the family Paramyxoviridae has led to significant loss of lives till date with the most recent outbreak in India reported in Kerala. The virus has a considerably high mortality rate along with lack of characteristic symptoms which results in the delay of the virus detection. No specific vaccine is available for the virus although monoclonal antibody treatment has been seen to be effective along with favipiravir. The high mortality and complications caused by the virus underscores the necessity to develop alternative modes of vaccination. One such method has been designed in this study using peptide cocktail consisting of the immunologically important epitopes for use as vaccine. The human leucocytic antigens that are used for the study were analyzed for their presence in various ethnic Indian populations. This study may serve as a new avenue for development of more efficient peptide cocktail vaccines in recent future based on the population genetics and ethnicity.

Randomized open-label controlled study of cancer vaccine OSE2101 versus chemotherapy in HLA-A2-positive patients with advanced non-small-cell lung cancer with resistance to immunotherapy: ATALANTE-1

BACKGROUND

Patients with advanced non-small-cell lung cancer (NSCLC) treated with immune checkpoint blockers (ICBs) ultimately progress either rapidly (primary resistance) or after durable benefit (secondary resistance). The cancer vaccine OSE2101 may invigorate antitumor-specific immune responses after ICB failure. The objective of ATALANTE-1 was to evaluate its efficacy and safety in these patients.

PATIENTS AND METHODS

ATALANTE-1 was a two-step open-label study to evaluate the efficacy and safety of OSE2101 compared to standard-of-care (SoC) chemotherapy (CT). Patients with human leukocyte antigen (HLA)-A2-positive advanced NSCLC without actionable alterations, failing sequential or concurrent CT and ICB were randomized (2 : 1) to OSE2101 or SoC (docetaxel or pemetrexed). Primary endpoint was overall survival (OS). Interim OS futility analysis was planned as per Fleming design. In April 2020 at the time of interim analysis, a decision was taken to prematurely stop the accrual due to coronavirus disease 2019 (COVID-19). Final analysis was carried out in all patients and in the subgroup of patients with ICB secondary resistance defined as failure after ICB monotherapy second line ≥12 weeks.

RESULTS

Two hundred and nineteen patients were randomized (139 OSE2101, 80 SoC); 118 had secondary resistance to sequential ICB. Overall, median OS non-significantly favored OSE2101 over SoC {hazard ratio (HR) [95% confidence interval (CI)] 0.86 [0.62-1.19], P = 0.36}. In the secondary resistance subgroup, OSE2101 significantly improved median OS versus SoC [11.1 versus 7.5 months; HR (95% CI) 0.59 (0.38-0.91), P = 0.017], and significantly improved post-progression survival (HR 0.46, P = 0.004), time to Eastern Cooperative Oncology Group (ECOG) performance status deterioration (HR 0.43, P = 0.006) and Quality of Life Questionnaire Core 30 (QLQ-C30) global health status compared to SoC (P = 0.045). Six-month disease control rates and progression-free survival were similar between groups. Grade ≥3 adverse effects occurred in 11.4% of patients with OSE2101 and 35.1% in SoC (P = 0.002).

CONCLUSIONS

In HLA-A2-positive patients with advanced NSCLC and secondary resistance to immunotherapy, OSE2101 increased survival with better safety compared to CT. Further evaluation in this population is warranted.

Current progress in the development of prophylactic and therapeutic vaccines

Vaccines are essential public health tools and play an important role in reducing the burden of infectious diseases in the population. Emerging infectious diseases and outbreaks pose new challenges for vaccine development, requiring the rapid design and production of safe and effective vaccines against diseases with limited resources. Here, we focus on the development of vaccines in broad fields ranging from conventional prophylactic vaccines against infectious diseases to therapeutic vaccines against chronic diseases and cancer providing a comprehensive overview of recent advances in eight different vaccine forms (live attenuated vaccines, inactivated vaccines, polysaccharide and polysaccharide conjugate vaccines, recombinant subunit vaccines, virus-like particle and nanoparticle vaccines, polypeptide vaccines, DNA vaccines, and mRNA vaccines) and the therapeutic vaccines against five solid tumors (lung cancer breast cancer colorectal cancer liver cancer and gastric cancer), three infectious diseases (human immunodeficiency virus, hepatitis B virus and human papillomavirus-induced diseases) and three common chronic diseases (hypertension, diabetes mellitus and dyslipidemia). We aim to provide new insights into vaccine technologies, platforms, applications and understanding of potential next-generation preventive and therapeutic vaccine technologies paving the way for the vaccines design in the future.

Potential association factors for developing effective peptide-based cancer vaccines

Peptide-based cancer vaccines have been shown to boost immune systems to kill tumor cells in cancer patients. However, designing an effective T cell epitope peptide-based cancer vaccine still remains a challenge and is a major hurdle for the application of cancer vaccines. In this study, we constructed for the first time a library of peptide-based cancer vaccines and their clinical attributes, named CancerVaccine (https://peptidecancervaccine.weebly.com/). To investigate the association factors that influence the effectiveness of cancer vaccines, these peptide-based cancer vaccines were classified into high (HCR) and low (LCR) clinical responses based on their clinical efficacy. Our study highlights that modified peptides derived from artificially modified proteins are suitable as cancer vaccines, especially for melanoma. It may be possible to advance cancer vaccines by screening for HLA class II affinity peptides may be an effective therapeutic strategy. In addition, the treatment regimen has the potential to influence the clinical response of a cancer vaccine, and Montanide ISA-51 might be an effective adjuvant. Finally, we constructed a high sensitivity and specificity machine learning model to assist in designing peptide-based cancer vaccines capable of providing high clinical responses. Together, our findings illustrate that a high clinical response following peptide-based cancer vaccination is correlated with the right type of peptide, the appropriate adjuvant, and a matched HLA allele, as well as an appropriate treatment regimen. This study would allow for enhanced development of cancer vaccines.

Beyond Checkpoint Inhibitors: Enhancing Antitumor Immune Response in Lung Cancer

The introduction of immune checkpoint inhibitors has dramatically changed the treatment landscape and improved survival for many patients with thoracic malignancies. Although some patients may experience prolonged survival benefit with immune checkpoint inhibitors, a majority do not experience disease control or benefit, supporting the need for research and development of improved approaches for facilitating immune recognition. Additionally, many patients will experience toxicity with the current approaches to immunotherapy, supporting the need for developing treatment strategies with less risk of adverse events. An extensive array of different strategies are currently under investigation, including novel combinations of checkpoint inhibitors or immunotherapies; novel agents beyond checkpoint inhibitors (e.g., bispecific antibodies, vaccine strategies, cytokine therapies); and different approaches for use of radiation to augment systemic immunotherapy agents. With each strategy, researchers are evaluating the potential for augmenting antitumor responses and ensuring more sustained antitumor effects. This article highlights areas of active research, reviewing the rationale for different investigative strategies, as well as currently available clinical data.

Inmunoterapia personalizada contra el cáncer basada en neoantígenos. Revisión de la literatura

Introducción. Los avances que se han hecho en inmunoterapia contra el cáncer y la respuesta clínica de los pacientes que han recibido este tipo de terapia la han convertido en el cuarto pilar para el tratamiento del cáncer. Objetivo. Describir brevemente el fundamento biológico de la inmunoterapia personalizada contra el cáncer basada en neoantígenos, las perspectivas actuales de su desarrollo y algunos resultados clínicos de esta terapia. Materiales y métodos. Se realizó una búsqueda de la literatura en PubMed, Scopus y EBSCO utilizando la siguiente estrategia de búsqueda: tipo de artículos: estudios experimentales originales, ensayos clínicos y revisiones narrativas y sistemáticas sobre métodos de identificación de mutaciones generadas en los tumores y estrategias de inmunoterapia del cáncer con vacunas basadas en neoantígenos; población de estudio: humanos y modelos animales; periodo de publicación: enero 1989- diciembre 2019; idioma: inglés y español; términos de búsqueda: “Immunotherapy”, “Neoplasms”, “Mutation” y “Cancer Vaccines”. Resultados. La búsqueda inicial arrojó 1344 registros; luego de remover duplicados (n=176), 780 fueron excluidos luego de leer su resumen y título, y se evaluó el texto completo de 338 para verificar cuáles cumplían con los criterios de inclusión, seleccionándose finalmente 73 estudios para análisis completo. Todos los artículos recuperados se publicaron en inglés, y fueron realizados principalmente en EE. UU. (43.83%) y Alemania (23.65%). En el caso de los estudios originales (n=43), 20 se realizaron únicamente en humanos, 9 solo en animales, 2 en ambos modelos, y 12 usaron metodología in silico. Conclusión. La inmunoterapia personalizada contra el cáncer con vacunas basadas en neoantígenos tumorales se está convirtiendo de forma contundente en una nueva alternativa para tratar el cáncer. Sin embargo, para lograr su implementación adecuada, es necesario usarla en combinación con tratamientos convencionales, generar más conocimiento que contribuya a aclarar la inmunobiología del cáncer, y reducir los costos asociados con su producción.

An efficient T-cell epitope discovery strategy using in silico prediction and the iTopia assay platform

Functional T-cell epitope discovery is a key process for the development of novel immunotherapies, particularly for cancer immunology. In silico epitope prediction is a common strategy to try to achieve this objective. However, this approach suffers from a significant rate of false-negative results and epitope ranking lists that often are not validated by practical experience. A high-throughput platform for the identification and prioritization of potential T-cell epitopes is the iTopia(TM) Epitope Discovery System(TM), which allows measuring binding and stability of selected peptides to MHC Class I molecules. So far, the value of iTopia combined with in silico epitope prediction has not been investigated systematically. In this study, we have developed a novel in silico selection strategy based on three criteria: (1) predicted binding to one out of five common MHC Class I alleles; (2) uniqueness to the antigen of interest; and (3) increased likelihood of natural processing. We predicted in silico and characterized by iTopia 225 candidate T-cell epitopes and fixed-anchor analogs from three human tumor-associated antigens: CEA, HER2 and TERT. HLA-A2-restricted fragments were further screened for their ability to induce cell-mediated responses in HLA-A2 transgenic mice. The iTopia binding assay was only marginally informative while the stability assay proved to be a valuable experimental screening method complementary to in silico prediction. Thirteen novel T-cell epitopes and analogs were characterized and additional potential epitopes identified, providing the basis for novel anticancer immunotherapies. In conclusion, we show that combination of in silico prediction and an iTopia-based assay may be an accurate and efficient method for MHC Class I epitope discovery among tumor-associated antigens.

Designing precision medicine panels for drug refractory cancers targeting cancer stemness traits

Cancer is one amongst the major causes of death today and cancer biology is one of the most well researched fields in medicine. The driving force behind cancer is considered to be a minor subpopulation of cells, the cancer stem cells (CSCs). Similar to other stem cells, these cells are self-renewing and proliferating but CSCs are also difficult to target by chemo- or radio-therapies. Cancer stem cells are known to be present in most of the cancer subgroups such as carcinoma, sarcoma, myeloma, leukemia, lymphomas and mixed cancer types. There is a wide gamut of factors attributed to the stemness of cancers, ranging from dysregulated signaling pathways, and activation of enzymes aiding immune evasion, to conducive tumor microenvironment, to name a few. The defining outcome of the increased presence of CSCs is tumor metastasis and relapse. Predictive medicine approach based on the plethora of CSC markers would be a move towards precision medicine to specifically identify CSC-rich tumors. In this review, we discuss the cancer subtypes and the role of different CSC specific markers in these varying subtypes. We also categorize the CSC markers based their defining trait contributing to stemness. This review thus provides a comprehensive approach to catalogue a predictive set of markers to identify the resistant and refractory cancer stem cell population within different tumor subtypes, so as to facilitate better prognosis and targeted therapeutic strategies.

An overview of in silico vaccine design against different pathogens and cancer

INTRODUCTION

Due to overcome the hardness of the vaccine design, computational vaccinology is emerging widely. Prediction of T cell and B cell epitopes, antigen processing analysis, antigenicity analysis, population coverage, conservancy analysis, allergenicity assessment, toxicity prediction, and protein-peptide docking are important steps in the process of designing and developing potent vaccines against various viruses and cancers. In order to perform all of the analyses, several bioinformatics tools and online web servers have been developed. Scientists must take the decision to apply more suitable and precise servers for each part based on their accuracy.

AREAS COVERED

In this review, a wide-range list of different bioinformatics tools and online web servers has been provided. Moreover, some studies were proposed to show the importance of various bioinformatics tools for predicting and developing efficient vaccines against different pathogens including viruses, bacteria, parasites, and fungi as well as cancer.

EXPERT OPINION

Immunoinformatics is the best way to find potential vaccine candidates against different pathogens. Thus, the selection of the most accurate tools is necessary to predict and develop potent preventive and therapeutic vaccines. To further evaluation of the computational and in silico vaccine design, in vitro/in vivo analyses are required to develop vaccine candidates.

Immunology-Guided Biomaterial Design for Mucosal Cancer Vaccines

Cancer of mucosal tissues is a major cause of worldwide mortality for which only palliative treatments are available for patients with late-stage disease. Engineered cancer vaccines offer a promising approach for inducing antitumor immunity. The route of vaccination plays a major role in dictating the migratory pattern of lymphocytes, and thus vaccine efficacy in mucosal tissues. Parenteral immunization, specifically subcutaneous and intramuscular, is the most common vaccination route. However, this induces marginal mucosal protection in the absence of tissue-specific imprinting signals. To circumvent this, the mucosal route can be utilized, however degradative mucosal barriers must be overcome. Hence, vaccine administration route and selection of materials able to surmount transport barriers are important considerations in mucosal cancer vaccine design. Here, an overview of mucosal immunity in the context of cancer and mucosal cancer clinical trials is provided. Key considerations are described regarding the design of biomaterial-based vaccines that will afford antitumor immune protection at mucosal surfaces, despite limited knowledge surrounding mucosal vaccination, particularly aided by biomaterials and mechanistic immune-material interactions. Finally, an outlook is given of how future biomaterial-based mucosal cancer vaccines will be shaped by new discoveries in mucosal vaccinology, tumor immunology, immuno-therapeutic screens, and material-immune system interplay.

Design of multi-epitope peptides containing HLA class-I and class-II-restricted epitopes derived from immunogenic Leishmania proteins, and evaluation of CD4+ and CD8+ T cell responses induced in cured cutaneous leishmaniasis subjects

Human leishmaniasis is a public health problem worldwide for which the development of a vaccine remains a challenge. T cell-mediated immune responses are crucial for protection. Peptide vaccines based on the identification of immunodominant T cell epitopes able to induce T cell specific immune responses constitute a promising strategy. Here, we report the identification of human leukocyte antigen class-I (HLA-I) and -II (HLA-II)-restricted multi-epitope peptides from Leishmania proteins that we have previously described as vaccine candidates. Promastigote Surface Antigen (PSA), LmlRAB (L. major large RAB GTPase) and Histone (H2B) were screened, in silico, for T cell epitopes. 6 HLA-I and 5 HLA-II-restricted multi-epitope peptides, able to bind to the most frequent HLA molecules, were designed and used as pools to stimulate PBMCs from individuals with healed cutaneous leishmaniasis. IFN-γ, IL-10, TNF-α and granzyme B (GrB) production was evaluated by ELISA/CBA. The frequency of IFN-γ-producing T cells was quantified by ELISpot. T cells secreting cytokines and memory T cells were analyzed by flow cytometry. 16 of 25 peptide pools containing HLA-I, HLA-II or HLA-I and -II peptides were able to induce specific and significant IFN-γ levels. No IL-10 was detected. 6 peptide pools were selected among those inducing the highest IFN-γ levels for further characterization. 3/6 pools were able to induce a significant increase of the percentages of CD4+IFN-γ+, CD8+IFN-γ+ and CD4+GrB+ T cells. The same pools also induced a significant increase of the percentages of bifunctional IFN-γ+/TNF-α+CD4+ and/or central memory T cells. We identified highly promiscuous HLA-I and -II restricted epitope combinations from H2B, PSA and LmlRAB proteins that stimulate both CD4+ and CD8+ T cell responses in recovered individuals. These multi-epitope peptides could be used as potential components of a polytope vaccine for human leishmaniasis.

The control of leishmaniasis, a neglected tropical disease of public health importance, caused by protozoan parasites of the genus Leishmania, mainly relies on chemotherapy, which is highly toxic. Currently, there is no vaccine against human leishmaniasis. Peptide-based vaccines consisting of T cell epitopes identified within proteins of interest by epitope predictive algorithms are a promising strategy for vaccine development. Here, we identified multi-epitope peptides composed of HLA-I and -II-restricted epitopes, using immunoinformatic tools, within Leishmania proteins previously described as potential vaccine candidates. We showed that multi-epitope peptides used as pools were able to activate IFN-γ producing CD4+ as well as CD8+ T cells, both required for parasite elimination. In addition, granzyme B-producing CD4+ T cells, bifunctional CD4+ IFN-γ+/TNF-α+ and/or TNF-α+/IL-2+ T cells as well as CD4+ and CD8+ central memory T cells, all involved in Leishmania infection control, were significantly increased in response to multi-epitope peptide stimulation. As far as we know, no study has described the detection of both CD4+ and CD8+ T cell populations in response to stimulation by both HLA-I and II-restricted peptides in humans. The immunogenic HLA-I and -II-restricted multi-epitope peptides identified in this study could constitute potential vaccine candidates against human leishmaniasis.

Oncolytic Viruses Engineered to Enforce Leptin Expression Reprogram Tumor-Infiltrating T Cell Metabolism and Promote Tumor Clearance

Immunotherapy can reinvigorate dormant responses to cancer, but response rates remain low. Oncolytic viruses, which replicate in cancer cells, induce tumor lysis and immune priming, but their immune consequences are unclear. We profiled the infiltrate of aggressive melanomas induced by oncolytic Vaccinia virus using RNA sequencing and found substantial remodeling of the tumor microenvironment, dominated by effector T cell influx. However, responses to oncolytic viruses were incomplete due to metabolic insufficiencies induced by the tumor microenvironment. We identified the adipokine leptin as a potent metabolic reprogramming agent that supported antitumor responses. Leptin metabolically reprogrammed T cells in vitro, and melanoma cells expressing leptin were immunologically controlled in mice. Engineering oncolytic viruses to express leptin in tumor cells induced complete responses in tumor-bearing mice and supported memory development in the tumor infiltrate. Thus, leptin can provide metabolic support to tumor immunity, and oncolytic viruses represent a platform to deliver metabolic therapy.

Oncolytic Viral Therapy and the Immune System: A Double-Edged Sword Against Cancer

Oncolytic viral therapy is a new promising strategy against cancer. Oncolytic viruses (OVs) can replicate in cancer cells but not in normal cells, leading to lysis of the tumor mass. Beside this primary effect, OVs can also stimulate the immune system. Tumors are an immuno-suppressive environment in which the immune system is silenced in order to avoid the immune response against cancer cells. The delivery of OVs into the tumor wakes up the immune system so that it can facilitate a strong and durable response against the tumor itself. Both innate and adaptive immune responses contribute to this process, producing an immune response against tumor antigens and facilitating immunological memory. However, viruses are recognized by the immune system as pathogens and the consequent anti-viral response could represent a big hurdle for OVs. Finding a balance between anti-tumor and anti-viral immunity is, under this new light, a priority for researchers. In this review, we provide an overview of the various ways in which different components of the immune system can be allied with OVs. We have analyzed the different immune responses in order to highlight the new and promising perspectives leading to increased anti-tumor response and decreased immune reaction to the OVs.

Oncolytic Viruses-Interaction of Virus and Tumor Cells in the Battle to Eliminate Cancer

Oncolytic viruses (OVs) are an emerging treatment option for many cancer types and have recently been the focus of extensive research aiming to develop their therapeutic potential. The ultimate aim is to design a virus which can effectively replicate within the host, specifically target and lyse tumor cells and induce robust, long lasting tumor-specific immunity. There are a number of viruses which are either naturally tumor-selective or can be modified to specifically target and eliminate tumor cells. This means they are able to infect only tumor cells and healthy tissue remains unharmed. This specificity is imperative in order to reduce the side effects of oncolytic virotherapy. These viruses can also be modified by various methods including insertion and deletion of specific genes with the aim of improving their efficacy and safety profiles. In this review, we have provided an overview of the various virus species currently being investigated for their oncolytic potential and the positive and negative effects of a multitude of modifications used to increase their infectivity, anti-tumor immunity, and treatment safety, in particular focusing on the interaction of tumor cells and OVs.

Prognostic value of HLA-A2 status in advanced non-small cell lung cancer patients

INTRODUCTION

The class I human leucocyte antigen (HLA) molecules play a critical role as an escape mechanism of antitumoral immunity. HLA-A2 status has been evaluated as a prognostic factor in lung cancer, mostly in localized disease and with inconsistent findings. We evaluated the role of HLA-A2 status as a prognostic factor in a large and homogeneus cohort of advanced NSCLC patients.

METHODS

Advanced NSCLC patients eligible for platinum-based chemotherapy were consecutively included in a single center between October 2009 and July 2015 in the prospective MSN study (NCT02105168). HLA-A2 status was analysed by flow cytometry. Clinical, pathological and molecular data were collected. A Cox model was used for prognostic analyses.

RESULTS

Of 545 stage IIIB/IV NSCLC patients included, 344 (63%) were male, 466 (85%) were smokers, 447 (83%) had PS 0-1, 508 (93%) had stage IV, 407 (75%) had an adenocarcinoma and median age was 61 years (range, 21-84). Incidence of patients with EGFRmut, ALK-positive and KRASmut was 14% (49/361), 9% (29/333) and 31% (107/350), respectively. The overall rate of HLA-A2 positivity was 48%. No association was observed between HLA-A2 status and any patient or tumor characteristics analyzed. With a median follow-up of 27.1 months, median OS was 12.8 months [95%CI 11.0-14.6] in HLA-A2+ vs. 12.5 months [95%CI 10.4-15.3] in HLA-A2- patients (HR 1.05 [95%CI 0.86-1.29], p=0.61). Median progression-free survival was similar in the two cohorts.

CONCLUSION

HLA-A2 status was not identified as prognostic for benefit in a large advanced NSCLC population treated with platinum-based chemotherapy.

CpG oligodeoxynucleotides augment antitumor efficacy of folate receptor α based DNA vaccine

Folate receptor α (FRα) is overexpressed in a variety of solid tumors and has become an attractive target antigen for immunotherapy purposes. A DNA vaccine was generated by ligation of FRα cDNA into the eukaryotic vector pcDNA3.1. Expression of FRα was confirmed in transiently transfected B16 cells. B16 cell lines that stably express FRα were set up by G418 selection. A total of 100 µg purified plasmid DNA alone or in combination with CpG oligodeoxynucleotides (CpG ODN) was injected intramuscularly in C57BL/6 mice four times at one week intervals. ELISA analysis confirmed that high titers of antibodies against FRα existed in the sera of the experimental animals. Specific cytotoxic T lymphocyte activity against FRα-expressing B16 cells was found and FRα specific lymphocyte proliferation was detected. Coinjection of CpG ODN increased both humoral and cellular immune responses. In the protective model, in which C57BL/6 mice were immunized with the FRα DNA vaccine four weeks before tumor cell inoculation, the growth of tumor was significantly inhibited, and the presence of CpG ODN further increased the inhibitory effect. FRα DNA vaccine alone did not show a significant inhibitory effect in the therapeutic model, in which the DNA vaccine was immediately injected after tumor inoculation. However, FRα DNA vaccine plus CpG ODN showed a significant inhibitory effect in tumor growth. Survival curves for both animal experiments confirmed that mice immunized with pcDNA3.1/FRα plus CpG ODN had a significantly prolonged survival period than that of the pcDNA3.1 control group, the CpG ODN group or the pcDNA3.1/FRα group. The above showed that human FRα based DNA vaccination with CpG ODN as an adjuvant was effective in growth inhibition of a FRα expressing tumor in mice and deserves further evaluation as a possible immunotherapy.

Current status and future prospects of peptide-based cancer vaccines

Cancer immunotherapy has attracted attention worldwide owing to the recent development of immune checkpoint inhibitors. However, these therapies have shown limited efficacy, and further advancements are needed before these modalities can progress to widespread use. Immune checkpoint inhibitors are a type of nonspecific cancer immunotherapy, and antitumor effects are only observed when cancer-specific T cells are found within the nonspecifically activated T-cell group. In order to facilitate the development of potent immunotherapies, selective enhancement of cancer-specific T cells is essential. In this report, we discuss current and future perspectives, including the latest clinical trials of cancer-specific immunotherapies, particularly cancer peptide vaccines.

Approaches for targeting cancer stem cells drug resistance

INTRODUCTION

Several reports have suggested that a population of undifferentiated cells known as cancer stem cells (CSCs), is responsible for cancer formation and maintenance. In the last decade, the presence of CSCs in solid cancers have been reported. Areas covered: This review summarizes the main approaches for targeting CSCs drug resistance. It is indeed known that CSCs may contribute to resistance to conventional chemotherapy, radiotherapy and targeted agents. Among the mechanisms by which CSCs escape anticancer therapies, removal of therapeutic agents by drug efflux pumps, enhanced DNA damage repair, activation of mitogenic/anti-apoptotic pathways; the main features of CSCs, stemness and EMT, are involved, as well as the capability to evade immune response. Expert opinion: Different approaches are suitable to target CSCs mediated drug resistance. Some of them are currently under clinical evaluation in different cancer types. A better understanding of CSC biology, as well as more accurate study design, may maximize the therapeutic effects of these agents. In this respect, it is important to establish: (i) which molecules should be targeted; (ii) what drug combinations may be suitable; (iii) which patient settings will CSC targeting offer the highest clinical benefit; and (iv) how to integrate therapeutic approaches targeting CSCs with standard cancer therapy.

Efficacy of Tumor Vaccines and Cellular Immunotherapies in Non-Small-Cell Lung Cancer: A Systematic Review and Meta-Analysis

PURPOSE

Programmed cell death protein-1- checkpoint blockers have recently been approved as second-line treatment for advanced non-small-cell lung cancer (NSCLC). Unfortunately, only a subgroup of patients responds and shows long-term survival to these therapies. Tumor vaccines and cellular immunotherapies could synergize with checkpoint blockade, but which of these treatments is most efficacious is unknown. In this meta-analysis, we assessed the efficacy of tumor vaccination and cellular immunotherapy in NSCLC.

METHODS

We searched for randomized controlled trials (RCTs) investigating cellular immunotherapy or vaccines in NSCLC. We used random effects models to analyze overall survival (OS) and progression-free survival (PFS), expressed as hazard ratios (HRs), and differences in time (months). The effect of immunotherapy type, disease stage, tumor histology, and concurrent chemotherapy was assessed using subgroup analysis and meta-regression. All procedures were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

We identified 18 RCTs that matched our selection criteria; these included a total of 6,756 patients. Immunotherapy extended NSCLC survival and PFS, expressed as HR (OS: HR, 0.81, 95% CI, 0.70 to 0.94, P = .01; PFS: HR, 0.83, 95% CI, 0.72 to 0.95, P = .006) and month difference (OS: difference, 5.43 months, 95% CI, 3.20 to 7.65, P < .005; PFS: difference, 3.24 months, 95% CI, 1.61 to 4.88, P < .005). Cellular therapies outperformed tumor vaccines (OS as HR: P = .005, month difference: P < .001; PFS as HR: P = .001, month difference: P = .004). There was a benefit of immunotherapy in low-stage compared with high-stage NSCLC and with concurrent administration of chemotherapy only in one of four outcome measures evaluated (PFS in months: P = .01 and PFS as HR: P = .031, respectively). There was no significant effect of tumor histology on survival or PFS.

CONCLUSION

Tumor vaccines and cellular immunotherapies enhanced OS and PFS in NSCLC. Cellular immunotherapy was found to be more effective than tumor vaccination. These findings have implications for future studies investigating combination immunotherapy in NSCLC.

Phase I clinical trial of a five-peptide cancer vaccine combined with cyclophosphamide in advanced solid tumors

We designed a phase I trial to investigate the safety, immune responses and clinical benefits of a five-peptide cancer vaccine in combination with chemotherapy. Study subjects were patients positive for HLA-A2402 with locally advanced, metastatic, and/or recurrent gastrointestinal, lung or cervical cancer. Eighteen patients including nine cases of colorectal cancer were treated with escalating doses of cyclophosphamide 4days before vaccination. Five HLA-A2402-restricted, tumor-associated antigen (TAA) epitope peptides from KOC1, TTK, URLC10, DEPDC1 and MPHOSPH1 were injected weekly for 4weeks. Treatment was well tolerated without any adverse events above grade 3. Analysis of peripheral blood lymphocytes showed that the number of regulatory T cells dropped from baseline after administration of cyclophosphamide and confirmed that TAA-specific T cell responses were associated significantly with longer overall survival. This phase I clinical trial demonstrated safety and promising immune responses that correlated with vaccine-induced T-cell responses. Therefore, this approach warrants further clinical studies.

Cancer stem cells and immunoresistance: clinical implications and solutions

Tumor cells can be contained, but not eliminated, by traditional cancer therapies. A cell minor subpopulation is able to evade attack from therapies and may have cancer stem cell (CSC) characteristics, including self-renewal, multiple differentiation and tumor initiation (tumor initiating cells, or TICs). Thus, CSCs/TICs, aided by the microenvironment, produce more differentiated, metastatic cancer cells which the immune system detects and interacts with. There are three phases to this process: elimination, equilibrium and escape. In the elimination phase the immune system recognizes and destroys most of the tumor cells. Then the latency phase begins, consisting of equilibrium between immunological elimination and tumor cell growth. Finally, a minor attack-resistant subpopulation escapes and forms a clinically detectable tumor mass. Herein we review current knowledge of immunological characterization of CSCs/TICs. Due to the correlation between CTCs/TICs and drug resistance and metastasis, we also comment on the crucial role of key molecules involved in controlling CSCs/TICs properties; such molecules are essential to detect and destroy CSCs/TICs. Monoclonal antibodies, antibody constructs and vaccines have been designed to act against CSCs/TICs, with demonstrated efficacy in human cancer xenografts and some antitumor activity in human clinical studies. Therefore, therapeutic strategies that selectively target CSCs/TICs warrant further investigation. Better understanding of the interaction between CSCs and tumor immunology may help to identify strategies to eradicate the minor subpopulation that escapes conventional therapy attack, thus providing a solution to the problem of drug resistance and metastasis.

A phase III study of belagenpumatucel-L, an allogeneic tumour cell vaccine, as maintenance therapy for non-small cell lung cancer

BACKGROUND

Treatment options after first-line chemotherapy are limited in non-small cell lung cancer (NSCLC). Belagenpumatucel-L is a therapeutic vaccine comprised of 4 transforming growth factor (TGF)-β2-antisense gene-modified, irradiated, allogeneic NSCLC cell lines that may be useful for maintenance after initial treatment.

METHODS

Stage III/IV NSCLC patients who did not progress after platinum-based chemotherapy were randomised 1:1 to receive maintenance belagenpumatucel-L or placebo. Patients were eligible for randomisation between one and four months from the end of induction chemotherapy. The primary endpoint was overall survival.

RESULTS

This phase III trial enrolled 270 patients in the belagenpumatucel-L arm and 262 in the control arm. Belagenpumatucel-L was well tolerated with no serious safety concerns. There was no difference in survival between the arms (median survival 20.3 versus 17.8months with belagenpumatucel-L versus placebo, respectively; hazard ratio (HR) 0.94, p=0.594). There were also no differences in progression-free survival (4.3months versus 4.0 for belagenpumatucel-L vs placebo, respectively; HR 0.99, p=0.947). A prespecified Cox regression analysis demonstrated that the time elapsed between randomisation and the end of induction chemotherapy had a significant impact on survival (p=0.002) and that prior radiation was a positive prognostic factor (median survival 28.4months with belagenpumatucel-L versus 16.0months with placebo; HR 0.61, p=0.032).

CONCLUSIONS

Although the overall trial did not meet its survival endpoint, improved survival for belagenpumatucel-L is suggested in patients who were randomised within 12weeks of completion of chemotherapy and in those who had received prior radiation. Further studies of belagenpumatucel-L in NSCLC are warranted.

Vaccine therapy in NSCLC: a review

SUMMARY 

Approximately 200,000 people will develop lung cancer in the USA this year. Roughly 85% of those will die of their disease. Standard chemotherapeutic agents have modestly prolonged survival in this population. The discovery of activating mutations, and their inhibitors has had a more significant impact, but this is limited to the small percentage of the population that harbor the currently known mutations with approved therapeutics. Recent advances in the field of immune checkpoint inhibitors like CTLA4 or PD1 have reinvigorated the interest in immunotherapy. In this review, we will analyze the most significant findings in the field of lung cancer vaccines, and will focus on the different methods of immune activation that attempt to induce a tumor specific response.

Cellular and molecular immunology of lung cancer: therapeutic implications

Although the incidence of lung cancer is declining, the prognosis remains poor. This is likely due to lack of early detection and only recent developments in selective cancer therapies. Key immune cells involved in the pathogenesis of lung cancer include CD4(+) T lymphocytes, macrophages, dendritic cells and NK cells. The growing understanding of these cells indicates a highly complex and intertwined network of their involvement in each stage of lung cancer. Immune cell types and numbers affect prognosis and could offer an opportunity for clinical therapeutic applications. However, an incomplete understanding of immune cell involvement and the underlying processes in lung cancer still remain. Deeper investigation focusing on the role of the immune cells will further the understanding of lung carcinogenesis and develop novel therapeutic approaches for the treatment and management of patients with more specialized and selective lung cancer.

The use of signal peptide domains as vaccine candidates

Signal peptide (SP) domains have a common motif but also sequence specific features. This knowledge was mainly ignored by immunologists who considered SP as generic, short-lived, targeting sequences. Consequently, while SP-derived MHC class I, class II and HLA-E epitopes have been isolated, their use as antigen-specific vaccine candidates (VCs) was mostly neglected. Recently we demonstrated the rational of selecting entire SP domains as multi-epitope long peptide VCs based on their high T and B-cell epitope densities. This review summarizes preclinical and clinical results demonstrating the various advantages of human SP domain VCs derived from both bacterial and tumor antigens. Such vaccine design provides for a straightforward, yet unique immunotherapeutic means of generating robust, non-toxic, diversified, combined antigen-specific CD4+/CD8+ T/B-cell immunity, irrespective of patient HLA repertoire also in disease associated transporter-associated with antigen processing (TAP) deficiencies. Subsequent clinical trials will further assess the full potential of this approach.

Clinical evaluation of CpG oligonucleotides as adjuvants for vaccines targeting infectious diseases and cancer

Synthetic oligonucleotides (ODN) that express unmethylated "CpG motifs" trigger cells that express Toll-like receptor 9. In humans this includes plasmacytoid dendritic cells and B cells. CpG ODN induce an innate immune response characterized by the production of Th1 and pro-inflammatory cytokines. Their utility as vaccine adjuvants was evaluated in a number of clinical trials. Results indicate that CpG ODN improve antigen presentation and the generation of vaccine-specific cellular and humoral responses. This work provides an up-to-date overview of the utility of CpG ODN as adjuvants for vaccines targeting infectious agents and cancer.

Phase II trial of a GM-CSF-producing and CD40L-expressing bystander cell line combined with an allogeneic tumor cell-based vaccine for refractory lung adenocarcinoma

We created a vaccine in which irradiated allogeneic lung adenocarcinoma cells are combined with a bystander K562 cell line transfected with hCD40L and hGM-CSF. By recruiting and activating dendritic cells, we hypothesized that the vaccine would induce tumor regression in metastatic lung adenocarcinoma. Intradermal vaccine was given q14 days×3, followed by monthly ×3. Cyclophosphamide (300 mg/m IV) was administered before the first and fourth vaccines to deplete regulatory T cells. All-trans retinoic acid was given (150/mg/m/d) after the first and fourth vaccines to enhance dendritic cell differentiation. Twenty-four participants were accrued at a single institution from October 2006 to June 2008, with a median age 64 years and median of 4 previous lines of systemic therapy. A total of 101 vaccines were administered. Common toxicities were headache (54%) and site reaction (38%). No radiologic responses were observed. Median overall survival was 7.9 months and median progression-free survival was 1.7 months. Of 14 patients evaluable for immunological study, 5 had peptide-induced CD8 T-cell activation after vaccination. Overall, vaccine administration was feasible in an extensively pretreated population of metastatic lung cancer. Despite a suggestion of clinical activity in the subset with immune response, the trial did not meet the primary endpoint of inducing radiologic tumor regression.

Prothymosin α and a prothymosin α-derived peptide enhance T(H)1-type immune responses against defined HER-2/neu epitopes

Background

Active cancer immunotherapies are beginning to yield clinical benefit, especially those using peptide-pulsed dendritic cells (DCs). Different adjuvants, including Toll-like receptor (TLR) agonists, commonly co-administered to cancer patients as part of a DC-based vaccine, are being widely tested in the clinical setting. However, endogenous DCs in tumor-bearing individuals are often dysfunctional, suggesting that ex vivo educated DCs might be superior inducers of anti-tumor immune responses. We have previously shown that prothymosin alpha (proTα) and its immunoreactive decapeptide proTα(100–109) induce the maturation of human DCs in vitro. The aim of this study was to investigate whether proTα- or proTα(100–109)-matured DCs are functionally competent and to provide preliminary evidence for the mode of action of these agents.

Results

Monocyte-derived DCs matured in vitro with proTα or proTα(100–109) express co-stimulatory molecules and secrete pro-inflammatory cytokines. ProTα- and proTα(100–109)-matured DCs pulsed with HER-2/neu peptides induce T_H1-type immune responses, prime autologous naïve CD8-positive (+) T cells to lyse targets expressing the HER-2/neu epitopes and to express a polyfunctional profile, and stimulate CD4+ T cell proliferation in an HER-2/neu peptide-dependent manner. DC maturation induced by proTα and proTα(100–109) is likely mediated via TLR-4, as shown by assessing TLR-4 surface expression and the levels of the intracellular adaptor molecules TIRAP, MyD88 and TRIF.

Conclusions

Our results suggest that proTα and proTα(100–109) induce both the maturation and the T cell stimulatory capacity of DCs. Although further studies are needed, evidence for a possible proTα and proTα(100–109) interaction with TLR-4 is provided. The initial hypothesis that proTα and the proTα-derived immunoactive decapeptide act as “alarmins”, provides a rationale for their eventual use as adjuvants in DC-based anti-cancer immunotherapy.

Lung cancer: potential targets for immunotherapy

Lung cancer is the most common cause of cancer-related mortality worldwide and a therapeutic challenge. Recent success with antibodies blocking immune checkpoints in non-small-cell lung cancers (NSCLC) highlights the potential of immunotherapy for lung cancer treatment, and the need for trials of combination regimens of immunotherapy plus chemotherapy that lead to immunogenic cell death. Here, we review the development of immunogenic cytotoxic compounds, vaccines, and antibodies in NSCLC, in view of their integration into personalised oncology.

Combinational delivery of lipid-enveloped polymeric nanoparticles carrying different peptides for anti-tumor immunotherapy

AIM

The authors aimed to investigate whether nanotechnology-based delivery of antigenic peptides is feasible for efficiently inducing anti-tumor cytotoxic T lymphocyte responses through vaccination.

MATERIALS & METHODS

Three different murine melanoma antigens were entrapped in lipid-coated poly(D,L-lactide-co-glycolide) nanoparticles (NPs) by the double emulsion method.

RESULTS

The loading efficiency of hydrophilic peptides was greatly improved when lipids were introduced to formulate lipid-coated NPs. The lipid-coated NPs carrying a single peptide and/or combinations of multiple lipid-coated NPs carrying antigenic peptides were characterized in vitro and in vivo in a C57/BL6 (B6) mouse model. Both the single melanoma antigen peptide-loaded NPs and combinational delivery of lipid-coated NPs carrying different peptides could induce antigen-specific T-cell responses. However, single peptide-loaded NPs failed to significantly delay the growth of subcutaneously inoculated B16 melanoma cells in a prophylactic setting. By contrast, the combinational delivery of lipid-coated NPs carrying different peptides significantly suppressed growth of inoculated B16 melanoma cells.

Cancer targeting vaccines: surrogate measures of activity

Recent FDA approval of sipuleucel-T and Ipilimumab as indicated immunologic therapy in patients with advanced prostate cancer and melanoma, respectively, has established a foothold for broader utilization of vaccine based technology in managing cancer.  Despite difficulty of cell harvest and processing with sipuleucel-T and modest toxicity to Ipilimumab, when matched up with the appropriate cancer patient these immunologic approaches have provided significant benefit and have stimulated exciting forward progress in the development of new potent and less toxic (more targeted) vaccines.  However, surrogate measures of activity to optimally define more sensitive subset populations and to determine length of treatment time in order to optimize management with other treatment options remain elusive.  Key clinically tested vaccines under development which demonstrate correlation of patient benefit to induced immune responsiveness will be discussed.  Results suggest with some vaccines correlation of patient benefit and surrogate measures of activity actually do exist.  Examples will be discussed.

Improving lung cancer survival; time to move on

BACKGROUND

During the past decades, numerous efforts have been made to decrease the death rate among lung cancer patients. Nonetheless, the improvement in long-term survival has been limited and lung cancer is still a devastating disease.

DISCUSSION

With this article we would like to point out that survival of lung cancer could be strongly improved by controlling two pivotal prognostic factors: stage and treatment. This is corresponding with recent reports that show a decrease in lung cancer mortality by screening programs. In addition, modulation of the patient's immune system by immunotherapy either as monotherapy or combined with conventional cancer treatments offers the prospect of tailoring treatments much more precisely and has also been shown to lead to a better response to treatment and overall survival of non-small cell lung cancer patients.

SUMMARY

Since only small improvements in survival can be expected in advanced disease with the use of conventional therapies, more research should be focused on lung cancer screening programs and patient tailored immunotherapy with or without conventional therapies. If these approaches are clinically combined in a standard multidisciplinary policy we might be able to advance the survival of patients with lung cancer.

Next-generation peptide vaccines for advanced cancer

Many clinical trials of peptide vaccines have been carried out since the first clinical trial of a melanoma antigen gene-1-derived peptide-based vaccine was reported in 1995. The earlier generations of peptide vaccines were composed of one to several human leukocyte antigen class I-restricted CTL-epitope peptides of a single human leukocyte antigen type. Currently, various types of next-generation peptide vaccines are under development. In this review, we focus on the clinical trials of the following categories of peptide vaccines mainly published from 2008 to 2012: (i) multivalent long peptide vaccines; (ii) multi-peptide vaccines consisting of CTL- and helper-epitopes; (iii) peptide cocktail vaccines; (iv) hybrid peptide vaccines; (v) personalized peptide vaccines; and (vi) peptide-pulsed dendritic cell vaccines.

Active-specific immunotherapy for non-small cell lung cancer

Non-small cell lung cancer constitutes about 85% of all newly diagnosed cases of lung cancer and continues to be the leading cause of cancer-related deaths worldwide. Standard treatment for this devastating disease, such as systemic chemotherapy, has reached a plateau in effectiveness and comes with considerable toxicities. For all stages of disease fewer than 20% of patients are alive 5 years after diagnosis; for metastatic disease the median survival is less than one year. Until now, the success of active-specific immunotherapy for all tumor types has been sporadic and unpredictable. However, the active-specific stimulation of the host's own immune system still holds great promise for achieving non-toxic and durable antitumor responses. Recently, sipuleucel-T (Provenge(®); Dendreon Corp., Seattle, WA) was the first therapeutic cancer vaccine to receive market approval, in this case for advanced prostate cancer. Other phase III clinical trials using time-dependent endpoints, e.g. in melanoma and follicular lymphoma, have recently turned out positive. More sophisticated specific vaccines have now also been developed for lung cancer, which, for long, was not considered an immune-sensitive malignancy. This may explain why advances in active-specific immunotherapy for lung cancer lag behind similar efforts in renal cell cancer, melanoma or prostate cancer. However, various vaccines are now being evaluated in controlled phase III clinical trials, raising hopes that active-specific immunotherapy may become an additional effective therapy for patients with lung cancer. This article reviews the most prominent active-specific immunotherapeutic approaches using protein/peptide, whole tumor cells, and dendritic cells as vaccines for lung cancer.

Lung cancer: a classic example of tumor escape and progression while providing opportunities for immunological intervention

Lung cancers remain one of the most common and deadly cancers in the world today (12.5% of newly diagnosed cancers) despite current advances in chemo- and radiation therapies. Often, by the time these tumors are diagnosed, they have already metastasized. These tumors demonstrate the classic hallmarks of cancer in that they have advanced defensive strategies allowing them to escape various standard oncological treatments. Immunotherapy is making inroads towards effectively treating other fatal cancers, such as melanoma, glioblastoma multiforme, and castrate-resistant prostate cancers. This paper will cover the escape mechanisms of bronchogenic lung cancer that must be overcome before they can be successfully treated. We also review the history of immunotherapy directed towards lung cancers.

Immunoglobulin light chain, Blimp-1 and cytochrome P4501B1 peptides as potential vaccines for AL amyloidosis

Amyloid light chain (AL) amyloidosis is a lethal disorder characterized by the pathologic deposition of clonal plasma cell-derived, fibrillogenic immunoglobulin light chains in vital organs. Current chemotherapeutic regimens are problematic in patients with compromised organ function and are not effective for all patients. Here, a platform of computer-based prediction and preclinical mouse modeling was used to begin development of a complementary, immunotherapeutic approach for AL amyloidosis. Three peptide/MHC I-binding algorithms identified immunogenic peptides from three AL plasma cell-associated proteins: (1) amyloidogenic λ6 light chains, (2) CYP1B1, a universal tumor antigen hyper-expressed in AL plasma cells and (3) B lymphocyte-induced maturation protein 1 (Blimp-1), a transcription factor required for plasma cell differentiation. The algorithms correctly predicted HLA-A(*)0201-binding native and heteroclitic peptides. In HLA-A2 transgenic mice, these peptides, given individually or in combination, induced potent CTL which kill peptide-loaded human lymphoma cells and/or lymphoma cells producing target protein. Blimp-1 peptide-immunized mice exhibited a reduced percentage of splenic, lymph node and bone marrow plasma cells and a decrease in the absolute number of splenic plasma cells demonstrating (1) presentation of target peptide by endogenous plasma cells and (2) appropriate CTL homing to lymphoid organs followed by killing of target plasma cells. These studies suggest that AL amyloidosis, with its relatively low tumor cell burden, may be an attractive target for peptide-based multivalent vaccines.

Lung cancer vaccines

To date, in lung cancer, early attempts to modulate the immune system via vaccine-based therapeutics have been unsuccessful. An improved understanding of tumor immunology has facilitated the production of more sophisticated lung cancer vaccines. It is anticipated that it will likely require multiple epitopes of a diverse set of genes restricted to multiple haplotypes to generate a truly effective vaccine that is able to overcome the various immunologic escape mechanisms that tumors employ. Other issues to overcome include optimal patient selection, which adjuvant agent to use, and how to adequately monitor for an immunologic response. This review discusses the most promising vaccination strategies for non-small cell lung cancer including the allogeneic tumor cell vaccine belagenpumatucel-L, which is a mixture of 4 allogeneic non-small cell lung cancer cell lines genetically modified to secrete an antisense oligonucleotide to transforming growth factor β2 and 3 other target protein-specific vaccines designed to induce responses against melanoma-associated antigen A3, mucin 1, and epidermal growth factor.

Peptide Based Vaccine Approaches for Cancer-A Novel Approach Using a WT-1 Synthetic Long Peptide and the IRX-2 Immunomodulatory Regimen

Therapeutic cancer vaccines have the potential to generate a long lasting immune response that will destroy tumor cells with specificity and safety, in contrast to many other current cancer therapies. Clinical success to date has been limited by a number of factors including choice of immunogenic cancer rejection antigens, optimization of vaccine platforms and immune adjuvants to effectively polarize the immune response, and incorporation of strategies to reverse cancer mediated immune suppression by utilization of effective adjuvant/immune modulators. WT-1 (Wilms' tumor gene 1) is a cancer antigen that is required for tumorigenesis, expressed in a high percentage of tumor cells and rarely expressed in adult normal cells. Moreover spontaneous immunity to WT-1 is seen in cancer patients and can be augmented with various therapeutic vaccine approaches. IRX-2 is an immune modulator with demonstrated preclinical and clinical pleiotropic immune activities including enhancement of the immune response to potential tumor antigens. This paper presents the rationale and preclinical data for utilizing the WT-1 tumor antigen in a novel vaccine platform consisting of a synthetic long peptide containing multiple class I and class II epitopes in combination with the IRX-2 immunomodulatory regimen to overcome immuno-suppressive pathways and enhance the anti-tumor response.