Immunotherapy of human cervical high-grade cervical intraepithelial neoplasia with microparticle-delivered human papillomavirus 16 E7 plasmid DNA

Safety, Efficacy, and Immunogenicity of Therapeutic Vaccines for Patients with High-Grade Cervical Intraepithelial Neoplasia (CIN 2/3) Associated with Human Papillomavirus: A Systematic Review

Despite the knowledge that HPV is responsible for high-grade CIN and cervical cancer, little is known about the use of therapeutic vaccines as a treatment. We aimed to synthesize and critically evaluate the evidence from clinical trials on the safety, efficacy, and immunogenicity of therapeutic vaccines in the treatment of patients with high-grade CIN associated with HPV. A systematic review of clinical trials adhering to the PRISMA 2020 statement in MEDLINE/PubMed, Embase, CENTRAL Cochrane, Web of Science, Scopus, and LILACS was undertaken, with no data or language restrictions. Primary endpoints related to the safety, efficacy, and immunogenicity of these vaccines were assessed by reviewing the adverse/toxic effects associated with the therapeutic vaccine administration via histopathological regression of the lesion and/or regression of the lesion size and via viral clearance and through the immunological response of individuals who received treatment compared to those who did not or before and after receiving the vaccine, respectively. A total of 1184 studies were identified, and 16 met all the criteria. Overall, the therapeutic vaccines were heterogeneous regarding their formulation, dose, intervention protocol, and routes of administration, making a meta-analysis unfeasible. In most studies (n = 15), the vaccines were safe and well tolerated, with clinical efficacy regarding the lesions and histopathological regression or viral clearance. In addition, eleven studies showed favorable immunological responses against HPV, and seven studies showed a positive correlation between immunogenicity and the clinical response, indicating promising results that should be further investigated. In summary, therapeutic vaccines, although urgently needed to avoid progression of CIN 2/3 patients, still present sparse data, requiring greater investments in a well-designed phase III RCT.

Polymeric nanoparticles for DNA vaccine-based cancer immunotherapy: a review

Cancer is one of the leading causes of death and mortality in the world. There is an essential need to develop new drugs or therapeutic approaches to manage treatment-resistant cancers. Cancer immunotherapy is a type of cancer treatment that uses the power of the body's immune system to prevent, control, and eliminate cancer. One of the materials used as a vaccine in immunotherapy is DNA. The application of polymeric nanoparticles as carriers for DNA vaccines could be an effective therapeutic approach to activate immune responses and increase antigen presentation efficiency. Various materials have been used as polymeric nanoparticles, including: chitosan, poly (lactic-co-glycolic acid), Polyethylenimine, dendrimers, polypeptides, and polyesters. Application of these polymer nanoparticles has several advantages, including increased vaccine delivery, enhanced antigen presentation, adjuvant effects, and more sustainable induction of the immune system. Besides many clinical trials and commercial products that were developed based on polymer nanoparticles, there is still a need for more comprehensive studies to increase the DNA vaccine efficiency in cancer immunotherapy using this type of carrier.

Governing HPV-related carcinoma using vaccines: Bottlenecks and breakthroughs

Human papillomavirus (HPV) contributes to sexually transmitted infection, which is primarily associated with pre-cancerous and cancerous lesions in both men and women and is among the neglected cancerous infections in the world. At global level, two-, four-, and nine-valent pure L1 protein encompassed vaccines in targeting high-risk HPV strains using recombinant DNA technology are available. Therapeutic vaccines are produced by early and late oncoproteins that impart superior cell immunity to preventive vaccines that are under investigation. In the current review, we have not only discussed the clinical significance and importance of both preventive and therapeutic vaccines but also highlighted their dosage and mode of administration. This review is novel in its way and will pave the way for researchers to address the challenges posed by HPV-based vaccines at the present time.

COVID-19 vaccine platforms: Delivering on a promise?

The emergence of the novel SARS-CoV-2 and COVID-19 has brought into sharp focus the need for a vaccine to prevent this disease. Vaccines have saved millions of lives since their introduction to the public over 200 years ago. The potential for vaccination reached new heights in the mid-20th century with the development of technologies that expanded the ability to create novel vaccines. Since then, there has been continued technological advancement in vaccine development. The resulting platforms provide the promise for solutions for many infectious diseases, including those that have been with us for decades as well as those just now emerging. Each vaccine platform represents a different technology with a unique set of advantages and challenges, especially when considering manufacturing. Therefore, it is essential to understand each platform as a separate product and process with its specific quality considerations. This review outlines the relevant platforms for developing a vaccine for SARS-CoV-2 and discusses the advantages and disadvantages of each.

Aliphatic Polyester-Based Materials for Enhanced Cancer Immunotherapy

Poly(lactic acid) (PLA) and its copolymer, poly(lactic-co-glycolic acid) (PLGA), based aliphatic polyesters have been extensively used for biomedical applications, such as drug delivery system and tissue engineering, thanks to their biodegradability, benign toxicity, renewability, and adjustable mechanical properties. A rapidly growing field of cancer research, the development of therapeutic cancer vaccines or treatment modalities is aimed to deliver immunomodulatory signals that control the quality of immune responses against tumors. Herein, the progress and applications of PLA and PLGA are reviewed in delivering immunotherapeutics to treat cancers.

Twenty years of research on HPV vaccines based on genetically modified lactic acid bacteria: an overview on the gut-vagina axis

Most cervical cancer (CxCa) are related to persistent infection with high-risk human papillomavirus (HR-HPV) in the cervical mucosa, suggesting that an induction of mucosal cell-mediated immunity against HR-HPV oncoproteins can be a promising strategy to fight HPV-associated CxCa. From this perspective, many pre-clinical and clinical trials have proved the potential of lactic acid bacteria (LAB) genetically modified to deliver recombinant antigens to induce mucosal, humoral and cellular immunity in the host. Altogether, the outcomes of these studies suggest that there are several key factors to consider that may offer guidance on improvement protein yield and improving immune response. Overall, these findings showed that oral LAB-based mucosal HPV vaccines expressing inducible surface-anchored antigens display a higher potential to induce particularly specific systemic and mucosal cytotoxic cellular immune responses. In this review, we describe all LAB-based HPV vaccine investigations by reviewing databases from international studies between 2000 and 2020. Our aim is to promote the therapeutic HPV vaccines knowledge and to complete the gaps in this field to empower scientists worldwide to make proper decisions regarding the best strategies for the development of therapeutic HPV vaccines.

Development of multiepitope therapeutic vaccines against the most prevalent high-risk human papillomaviruses

Aim: Our goal was the development of DNA- or peptide-based multiepitope vaccines targeting HPV E7, E6 and E5 oncoproteins in tumor mouse model. Materials & methods: After designing the multiepitope E7, E6 and E5 constructs from four types of high risk HPVs (16, 18, 31 & 45) using bioinformatics tools, mice vaccination was performed by different homologous and heterologous modalities in a prophylactic setting. Then, anti-tumor effects of the best prophylactic strategies were studied in a therapeutic setting. Results: In both prophylactic and therapeutic experiments, groups receiving homologous E7+E6+E5 polypeptide, and heterologous E7+E6+E5 DNA prime/polypeptide boost were successful in complete rejection of tumors. Conclusion: The designed multiepitope constructs can be considered as promising candidates to develop effective therapeutic HPV vaccines.

Materials for Immunotherapy

Breakthroughs in materials engineering have accelerated the progress of immunotherapy in preclinical studies. The interplay of chemistry and materials has resulted in improved loading, targeting, and release of immunomodulatory agents. An overview of the materials that are used to enable or improve the success of immunotherapies in preclinical studies is presented, from immunosuppressive to proinflammatory strategies, with particular emphasis on technologies poised for clinical translation. The materials are organized based on their characteristic length scale, whereby the enabling feature of each technology is organized by the structure of that material. For example, the mechanisms by which i) nanoscale materials can improve targeting and infiltration of immunomodulatory payloads into tissues and cells, ii) microscale materials can facilitate cell-mediated transport and serve as artificial antigen-presenting cells, and iii) macroscale materials can form the basis of artificial microenvironments to promote cell infiltration and reprogramming are discussed. As a step toward establishing a set of design rules for future immunotherapies, materials that intrinsically activate or suppress the immune system are reviewed. Finally, a brief outlook on the trajectory of these systems and how they may be improved to address unsolved challenges in cancer, infectious diseases, and autoimmunity is presented.

The First Clinical Use of a Recombinant Lactococcus lactis Expressing Human Papillomavirus Type 16 E7 Oncogene Oral Vaccine: A Phase I Safety and Immunogenicity Trial in Healthy Women Volunteers

A dose-escalation, randomized, double-blind, placebo-controlled phase I clinical trial was performed in healthy Iranian volunteer women to assess the safety, tolerability, and immunogenicity of NZ8123-HPV16-optiE7 vaccine involving recombinant Lactococcus lactis expressing the codon-optimized human papillomavirus (HPV)-16 E7 oncogene. Fifty-five eligible subjects were divided into 6 cohorts based on the dosages (1 × 10⁹, 5 × 10⁹, and 1 × 10¹⁰ CFU/mL) of either vaccine or placebo, which were administrated orally a total of 4 times at weeks 1, 2, 4, and 8. Then, adverse events, specific serum IgG and vaginal IgA, and E7-specific IFNγ-secreting CD8⁺ CTL responses were evaluated. The vaccination was well tolerated by 40 subjects who completed the immunization schedule, and no serious adverse effects were reported. The IgG and IgA levels peaked at day 60, and the levels for the 5 × 10⁹ CFU/mL and 1 × 10¹⁰ CFU/mL dose groups were higher than those for the 1 × 10⁹ CFU/mL dose group. Time-to-peak stimulation in E7-specific IFNγ-secreting CD8⁺ CTL responses was seen in cervical lymphocytes 1 month after the last vaccination. Again, no significant increase was seen in the peripheral blood mononuclear cells (PBMC) of the same volunteers. CTL responses in cervical lymphocytes and PBMCs at day 90 were markedly higher in the 5 × 10⁹ and 1 × 10¹⁰ CFU/mL groups than in the 1 × 10⁹ CFU/mL group, demonstrating the dose dependency of NZ8123-HPV16-optiE7 vaccine following oral administration. The 6-month follow-up revealed that antibody levels decreased up to day 240; nevertheless, long-term E7-specific IFNγ-secreting CD8⁺ CTL responses were recorded during follow-up. Overall, the safety and immunogenicity profile achieved in this study encourages further phase II trials with the 5 × 10⁹ CFU/mL dose vaccine.

Novel Approaches for Vaccination Against HPV-Induced Cancers

To date, more than 5 % of all cancers are as a result of human papillomavirus (HPV) infection, and this incidence is increasing. Early recognition of disease is associated with good survival, but late presentation results in devastating consequences. Prevention is better than cure, and there are now successful prophylactic vaccination programmes in place. We discuss these and the prospect of therapeutic vaccinations in the near future to address a growing need for improved therapeutic options.

Combined immunization against TGF-β1 enhances HPV16 E7-specific vaccine-elicited antitumour immunity in mice with grafted TC-1 tumours

Therapeutic vaccine appears to be a potential approach for the treatment of human papillomavirus (HPV)-associated tumours, but its efficacy can be dampened by immunosuppressive factors such as transforming growth factor (TGF)-β1. We sought to investigate whether active immunity against TGF-β1 enhances the anti-tumour immunity elicited by an HPV16 E7-specific vaccine that we developed previously. In this study, virus-like particles of hepatitis B virus core antigen were used as vaccine carriers to deliver either TGF-β1 B cell epitopes or E7 cytotoxic T-lymphocyte epitope. The combination of preventive immunization against TGF-β1 and therapeutic immunization with the E7 vaccine significantly reduced the growth of grafted TC-1 tumours in C57 mice, showing better efficacy than immunization with only one of the vaccines. The improved efficacy of combined immunization is evidenced by elevated IFN-γ and decreased IL-4 and TGF-β1 levels in cultured splenocytes, increased E7-specific IFN-γ-expressing splenocytes, and increased numbers of CD4⁺IFN-γ⁺ and CD8⁺IFN-γ⁺ cells and decreased numbers of Treg (CD4⁺Foxp3⁺) cells in the spleen and tumours. The results strongly indicate that targeting TGF-β1 through active immunization might be a potent approach to enhancing antigen-specific therapeutic vaccine-induced anti-tumour immune efficacy and providing a combined strategy for effective cancer immunotherapy.

Therapeutic vaccines and immune checkpoints inhibition options for gynecological cancers

Treatments for gynecological cancer include surgery, chemotherapy, and radiation. However, overall survival is not improved, and novel approaches are needed. Immunotherapy has been proven efficacious in various types of cancers and multiple approaches have been recently developed. Since numerous gynecological cancers are associated to human papilloma virus (HPV) infections, therapeutic vaccines, targeting HPV epitopes, have been developed. The advancing understanding of the immune system, regulatory pathways and tumor microenvironment have produced a major interest in immune checkpoint blockade, Indeed, immune checkpoint molecules are important clinical targets in a wide variety of tumors, including gynecological. In this review, we will describe the immunotherapeutic targets and modalities available and review the most recent immunotherapeutic clinical trials in the context of gynecological cancers. The synergic results obtained from the combination of HPV therapeutic vaccines with radiotherapy, chemotherapy, or immune checkpoint inhibitors, may underlie the potential for a novel therapeutic scenario for these tumors.

Immunotherapy for cervical cancer: Can it do another lung cancer?

Cervical cancer, although preventable, is still the second most common cancer among women worldwide. In developing countries like India, where screening for cervical cancer is virtually absent, most women seek treatment only at advanced stages of the disease. Although standard treatment is curative in more than 90% of women during the early stages, for stage IIIb and above this rate drops to 50% or less. Hence, novel therapeutic adjuvants are required to improve survival at advanced stages. Lung cancer has shown the way forward with the use of Immunotherapeutic interventions as standard line of treatment in advanced stages. In this review, we provide an overview of mechanisms of immune evasion, strategies that can be employed to boost the immune system in order to improve the overall survival of the patients and summarize briefly the clinical trials that have been completed or that are underway to bring therapeutic vaccines for cervical cancer to the clinics.

Targeted immunotherapy of high-grade cervical intra-epithelial neoplasia: Expectations from clinical trials

Targeted immunotherapy of high-grade cervical intra-epithelial neoplasia (CIN) has been developed as an alternative to conization, to preserve future reproductive outcomes and avoid human papillomavirus (HPV) persistence. The objectives of the review are to present drugs according to their process of development and to examine their potential future use. A search for key words associated with CIN and targeted immunotherapy was carried out in the Cochrane library, Pubmed, Embase, and ClinicalTrials.gov from 1990 to 2016. Publications (randomized, prospective and retrospective studies) in any language were eligible for inclusion, as well as ongoing trials registered on the ClinicalTrials.gov website. Targeted immunotherapy includes peptide/protein-based vaccines, nucleic acid-based vaccines (DNA), and live vector-based vaccines (bacterial or viral). A total of 18 vaccines were identified for treatment of CIN at various stages of development, and the majority were well-tolerated. Adverse effects were primarily injection site reactions and flu-like symptoms under grade 2. The efficacy of vaccines defined by regression of CIN2/3 to no CIN or CIN1 ranged from 17 to 59% following a minimum of a 12-week follow-up. In the majority of studies, there was no association demonstrated between histological response and HPV clearance, or between histological or virological response and immune T cell response. Given that the spontaneous regression of CIN2/3 is 20-25% at 6 months, targeted immunotherapy occurs an additional value, which never reaches 50%, with one trial an exception to this. However, research and development on HPV eradication drugs needs to be encouraged, due to HPV-associated disease burden.

Targeting immune response with therapeutic vaccines in premalignant lesions and cervical cancer: hope or reality from clinical studies

Human papillomavirus (HPV) is widely known as a cause of cervical cancer (CC) and cervical intraepithelial neoplasia (CIN). HPVs related to cancer express two main oncogenes, i.e. E6 and E7, considered as tumorigenic genes; their integration into the host genome results in the abnormal regulation of cell cycle control. Due to their peculiarities, these oncogenes represent an excellent target for cancer immunotherapy. In this work the authors highlight the potential use of therapeutic vaccines as safe and effective pharmacological tools in cervical disease, focusing on vaccines that have reached the clinical trial phase. Many therapeutic HPV vaccines have been tested in clinical trials with promising results. Adoptive T-cell therapy showed clinical activity in a phase II trial involving advanced CC patients. A phase II randomized trial showed clinical activity of a nucleic acid-based vaccine in HPV16 or HPV18 positive CIN. Several trials involving peptide-protein-based vaccines and live-vector based vaccines demonstrated that these approaches are effective in CIN as well as in advanced CC patients. HPV therapeutic vaccines must be regarded as a therapeutic option in cervical disease. The synergic combination of HPV therapeutic vaccines with radiotherapy, chemotherapy, immunomodulators or immune checkpoint inhibitors opens a new and interesting scenario in this disease.

A pilot study of pNGVL4a-CRT/E7(detox) for the treatment of patients with HPV16+ cervical intraepithelial neoplasia 2/3 (CIN2/3)

OBJECTIVE

The purpose of this study was to evaluate the safety, efficacy, and immunogenicity of a plasmid vaccine, pNGVL4a-CRT-E7(detox), administered either intradermally, intramuscularly, or directly into the cervical lesion, in patients with HPV16-associated CIN2/3.

METHODS

Eligible patients with HPV16(+) CIN2/3 were enrolled in treatment cohorts evaluating pNGVL4a-CRT-E7(detox), administered by either particle-mediated epidermal delivery (PMED), intramuscular injection (IM), or cervical intralesional injection, at study weeks 0, 4, and 8. Patients were monitored for local injection site and systemic toxicity. A standard therapeutic resection was performed at week 15. The primary endpoints were safety and tolerability. Secondary endpoints included histologic regression and change in cervical HPV viral load. Exploratory endpoints included immune responses in the blood and in the target tissue.

RESULTS

Thirty-two patients with HPV16(+) CIN2/3 were enrolled onto the treatment phase of the study, and were vaccinated. Twenty-two of 32 patients (69%) experienced vaccine-specific related adverse events. The most frequent vaccine-related events were constitutional and local injection site in nature, and were grade 1 or less in severity. Histologic regression to CIN 1 or less occurred in 8 of 27 (30%) patients who received all vaccinations and underwent LEEP. In subject-matched comparisons, intraepithelial CD8+ T cell infiltrates increased after vaccination in subjects in the intralesional administration cohort.

CONCLUSION

pNGVL4a-CRT-E7(detox) was well-tolerated, elicited the most robust immune response when administered intralesionally, and demonstrated preliminary evidence of potential clinical efficacy.

Cross-Reactivity, Epitope Spreading, and De Novo Immune Stimulation Are Possible Mechanisms of Cross-Protection of Nonvaccine Human Papillomavirus (HPV) Types in Recipients of HPV Therapeutic Vaccines

Numerous versions of human papillomavirus (HPV) therapeutic vaccines designed to treat individuals with established HPV infection, including those with cervical intraepithelial neoplasia (CIN), are in development because approved prophylactic vaccines are not effective once HPV infection is established. As human papillomavirus 16 (HPV-16) is the most commonly detected type worldwide, all versions of HPV therapeutic vaccines contain HPV-16, and some also contain HPV-18. While these two HPV types are responsible for approximately 70% of cervical cancer cases, there are other high-risk HPV types known to cause malignancy. Therefore, it would be of interest to assess whether these HPV therapeutic vaccines may confer cross-protection against other high-risk HPV types. Data available from a few clinical trials that enrolled subjects with CINs regardless of the HPV type(s) present demonstrated clinical responses, as measured by CIN regression, in subjects with both vaccine-matched and nonvaccine HPV types. The currently available evidence demonstrating cross-reactivity, epitope spreading, and de novo immune stimulation as possible mechanisms of cross-protection conferred by investigational HPV therapeutic vaccines is discussed.

Therapeutic Vaccine Strategies against Human Papillomavirus

High-risk types of human papillomavirus (HPV) cause over 500,000 cervical, anogenital and oropharyngeal cancer cases per year. The transforming potential of HPVs is mediated by viral oncoproteins. These are essential for the induction and maintenance of the malignant phenotype. Thus, HPV-mediated malignancies pose the unique opportunity in cancer vaccination to target immunologically foreign epitopes. Therapeutic HPV vaccination is therefore an ideal scenario for proof-of-concept studies of cancer immunotherapy. This is reflected by the fact that a multitude of approaches has been utilized in therapeutic HPV vaccination design: protein and peptide vaccination, DNA vaccination, nanoparticle- and cell-based vaccines, and live viral and bacterial vectors. This review provides a comprehensive overview of completed and ongoing clinical trials in therapeutic HPV vaccination (summarized in tables), and also highlights selected promising preclinical studies. Special emphasis is given to adjuvant science and the potential impact of novel developments in vaccinology research, such as combination therapies to overcome tumor immune suppression, the use of novel materials and mouse models, as well as systems vaccinology and immunogenetics approaches.

Enhanced therapeutic effects conferred by an experimental DNA vaccine targeting human papillomavirus-induced tumors

Human papillomavirus (HPV) infection is responsible for all cervical cancer cases, other anogenital cancers, and head and neck tumors. The epidemiological relevance of HPV-induced tumors reinforces the need for the development of therapeutic antitumor vaccines. Clinical trials with different vaccine formulations, particularly DNA vaccines, have provided promising results but have still been unable to achieve the immunogenicity required for use in infected patients. In experimental conditions, anticancer HPV-specific vaccines induced E7-specific CD8(+) T-cell responses but did not confer full therapeutic antitumor protection in mice with transplanted HPV-expressing TC-1 cells, which are the most frequently used nonclinical protection correlate for antitumor effects. Our group has developed a DNA vaccine strategy based on the fusion of HPV oncoproteins to the herpes virus gD protein. This vaccine promoted the induction of antigen-specific cytotoxic CD8(+) T-cell responses and partial antitumor therapeutic effects based on the blockade of coinhibitory signals and the enhancement of coactivation mechanisms. In the present study, we report conditions leading to full therapeutic antitumor effects using the TC-1 cell murine model after a single vaccine dose. The combination of a coadministered plasmid encoding IL-2, optimization of the coding sequence for mammalian cells, and the use of different delivery routes resulted in enhancements of the E7-specific cytotoxic CD8(+) T-cell responses and full therapeutic protection under experimental conditions. The combination of these strategies augmented the potency of the DNA vaccine formulation to levels not previously achieved by other therapeutic antitumor vaccines under similar experimental conditions, including some that have been taken to clinical trials.

Potential anti-HPV and related cancer agents from marine resources: an overview

Recently, the studies on the prevention and treatment of human papillomavirus (HPV) which is closely related to the cervical cancer and other genital diseases are attracting more and more attention all over the world. Marine-derived polysaccharides and other bioactive compounds have been shown to possess a variety of anti-HPV and related cancer activities. This paper will review the recent progress in research on the potential anti-HPV and related cancer agents from marine resources. In particular, it will provide an update on the anti-HPV actions of heparinoid polysaccharides and bioactive compounds present in marine organisms, as well as the therapeutic vaccines relating to marine organisms. In addition, the possible mechanisms of anti-HPV actions of marine bioactive compounds and their potential for therapeutic application will also be summarized in detail.

Immunologic treatments for precancerous lesions and uterine cervical cancer

Development of HPV-associated cancers not only depends on efficient negative regulation of cell cycle control that supports the accumulation of genetic damage, but also relies on immune evasion that enable the virus to go undetected for long periods of time. In this way, HPV-related tumors usually present MHC class I down-regulation, impaired antigen-processing ability, avoidance of T-cell mediated killing, increased immunosuppression due to Treg infiltration and secrete immunosuppressive cytokines. Thus, these are the main obstacles that immunotherapy has to face in the treatment of HPV-related pathologies where a number of different strategies have been developed to overcome them including new adjuvants. Although antigen-specific immunotherapy induced by therapeutic HPV vaccines was proved extremely efficacious in pre-clinical models, its progression through clinical trials suffered poor responses in the initial trials. Later attempts seem to have been more promising, particularly against the well-defined precursors of cervical, anal or vulvar cancer, where the local immunosuppressive milieu is less active. This review focuses on the advances made in these fields, highlighting several new technologies (such as mRNA vaccine, plant-derived vaccine). The most promising immunotherapies used in clinical trials are also summarized, along with integrated strategies, particularly promising in controlling tumor metastasis and in eliminating cancer cells altogether.

After the early promising clinical results, the development of therapeutic HPV vaccines need to be implemented and applied to the users in order to eradicate HPV-associated malignancies, eradicating existing perception (after the effectiveness of commercial preventive vaccines) that we have already solved the problem.

Cervical Cancer: Development of Targeted Therapies Beyond Molecular Pathogenesis

It is well known that human papillomavirus (HPV) is the causative agent of cervical cancer. The integration of HPV genes into the host genome causes the upregulation of E6 and E7 oncogenes. E6 and E7 proteins inactivate and degrade tumor suppressors p53 and retinoblastoma, respectively, leading to malignant progression. HPV E6 and E7 antigens are ideal targets for the development of therapies for cervical cancer and precursor lesions because they are constitutively expressed in infected cells and malignant tumors but not in normal cells and they are essential for cell immortalization and transformation. Immunotherapies are being developed to target E6/E7 by eliciting antigen-specific immune responses. siRNA technologies target E6/E7 by modulating the expression of the oncoproteins. Proteasome inhibitors and histone deacetylase inhibitors are being developed to indirectly target E6/E7 by interfering with their oncogenic activities. The ultimate goal for HPV-targeted therapies is the progression through clinical trials to commercialization.

Control of HPV infection and related cancer through vaccination

Human papillomavirus (HPV), the most common sexually transmitted virus, and its associated diseases continue to cause significant morbidity and mortality in over 600 million infected individuals. Major progress has been made with preventative vaccines, and clinical data have emerged regarding the efficacy and cross-reactivity of the two FDA approved L1 virus like particle (VLP)-based vaccines. However, the cost of the approved vaccines currently limits their widespread use in developing countries which carry the greatest burden of HPV-associated diseases. Furthermore, the licensed preventive HPV vaccines only contain two high-risk types of HPV (HPV-16 and HPV-18) which can protect only up to 75 % of all cervical cancers. Thus, second generation preventative vaccine candidates hope to address the issues of cost and broaden protection through the use of more multivalent L1-VLPs, vaccine formulations, or alternative antigens such as L1 capsomers, L2 capsid proteins, and chimeric VLPs. Preventative vaccines are crucial to controlling the transmission of HPV, but there are already hundreds of millions of infected individuals who have HPV-associated lesions that are silently progressing toward malignancy. This raises the need for therapeutic HPV vaccines that can trigger T cell killing of established HPV lesions, including HPV-transformed tumor cells. In order to stimulate such antitumor immune responses, therapeutic vaccine candidates deliver HPV antigens in vivo by employing various bacterial, viral, protein, peptide, dendritic cell, and DNA-based vectors. This book chapter will review the commercially available preventive vaccines, present second generation candidates, and discuss the progress of developing therapeutic HPV vaccines.

Polymeric nanoparticles: potent vectors for vaccine delivery targeting cancer and infectious diseases

Nanocarriers with various compositions and biological properties have been extensively applied for in vitro/in vivo drug and gene delivery. The family of nanocarriers includes polymeric nanoparticles, lipid-based carriers (liposomes/micelles), dendrimers, carbon nanotubes, and gold nanoparticles (nanoshells/nanocages). Among different delivery systems, polymeric carriers have several properties such as: easy to synthesize, inexpensive, biocompatible, biodegradable, non-immunogenic, non-toxic, and water soluble. In addition, cationic polymers seem to produce more stable complexes led to a more protection during cellular trafficking than cationic lipids. Nanoparticles often show significant adjuvant effects in vaccine delivery since they may be easily taken up by antigen presenting cells (APCs). Natural polymers such as polysaccharides and synthetic polymers have demonstrated great potential to form vaccine nanoparticles. The development of new adjuvants or delivery systems for DNA and protein immunization is an expanding research field. This review describes polymeric carriers especially PLGA, chitosan, and PEI as vaccine delivery systems.

Tailored immunotherapy for HPV positive head and neck squamous cell cancer

Human papilloma virus (HPV) associated oropharynx carcinoma (OPC) is increasingly common, with a distinct biology from HPV negative OPC. In spite of this better prognosis, morbidity is significant and treatment related after effects can be debilitating. Because the foreign viral proteins that drive HPV+ cancers are known, there are multiple options for tailored immune therapies. Herein we review the immunologic basis for disease and emerging immune therapies. The oncogenesis of HPV+ SCCHN goes beyond cell cycle deregulation, and relies on the immune escape through (E5, E6, and E7) downregulating antigen processing, interferon response, as well as STAT-1 signaling. Individual susceptibilities to HPV infection may vary. The treatment of HPV+ cancers has had a wide range of successes and failures. Perhaps the shining example of immunoprevention has been the L1 protein vaccines developed for cervical cancer prevention, however this vaccine has not been beneficial for people already infected. Therefore multiple strategies have been employed in the cancer therapeutic realm for people with existing disease. These agents range from peptides, to viral vectors, to adoptive cell therapy. In this review we consider the work done in both SCCHN and cervical cancer, as these therapeutic targets are the similar. The listed studies are not exhaustive, but rather illustrate experimental design and approach.

Human papillomavirus therapeutic vaccines: targeting viral antigens as immunotherapy for precancerous disease and cancer

Infections with oncogenic HPV types have the potential to lead to the induction of several types of cancer, notably cervical, vulvar, anal, and head and neck cancer. While prophylactic vaccines are currently available and show high efficacy against the establishment of HPV infection, low rates of initiation and lower rates of completion of the vaccination regimen, as well as the lack of an opportunity to be vaccinated prior to infection, has lead to the development of a patient population for whom no immune-based therapy for infection is available. In the current review the authors examine clinical approaches to HPV-targeted immune therapies, the bulk of which target the regulatory proteins E6 and E7 that are constitutively expressed in HPV-associated cancer cells. Early studies demonstrate a correlation between induction of T-cell responses and clearance of HPV-associated precancerous lesions. The clinical data corroborates these findings and highlight the importance of Th1 skewing. Improvements in our understanding of tumor immunology and development of more potent Th1-directed vaccine platforms make it feasible to foresee a HPV therapeutic vaccine in the coming years.

Micro and nanoparticle-based delivery systems for vaccine immunotherapy: an immunological and materials perspective

The development and widespread application of vaccines has been one of the most significant achievements of modern medicine. Vaccines have not only been instrumental in controlling and even eliminating life-threatening diseases like polio, measles, diphtheria, etc., but have also been immensely powerful in enhancing the worldwide outlook of public health over the past century. Despite these successes, there are still many complex disorders (e.g., cancer, HIV, and other emerging infectious diseases) for which effective preventative or therapeutic vaccines have been difficult to develop. This failure can be attributed primarily to our inability to precisely control and modulate the highly complex immune memory response, specifically the cellular response. Dominated by B and T cell maturation and function, the cellular response is primarily initiated by potent immunostimulators and antigens. Efficient and targeted delivery of these immunomodulatory and immunostimulatory molecules to appropriate cells is key to successful development of next generation vaccine formulations. Over the past decade, particulate carriers have emerged as an attractive means for enhancing the delivery efficacy and potency of vaccines and associated immunomodulatory molecules. Specifically, polymer-based micro and nanoparticles are being extensively studied for a wide variety of applications. In this review, we discuss the immunological fundamentals for developing effective vaccines and how materials and material properties can be exploited to improve these therapies. Particular emphasis is given to polymer-based particles and how the route of administration of particulate systems affects the phenotype and robustness of an immune response. Comparison of various strategies and recent advancements in the field are discussed along with insights into current limitations and future directions.

Emerging human papillomavirus vaccines

INTRODUCTION

Identification of human papillomavirus (HPV) as the etiologic factor of cervical, anogenital, and a subset of head and neck cancers has stimulated the development of preventive and therapeutic HPV vaccines to control HPV-associated malignancies. Excitement has been generated by the commercialization of two preventive L1-based vaccines, which use HPV virus-like particles (VLPs) to generate capsid-specific neutralizing antibodies. However, factors such as high cost and requirement for cold chain have prevented widespread implementation where they are needed most.

AREAS COVERED

Next generation preventive HPV vaccine candidates have focused on cost-effective stable alternatives and generating broader protection via targeting multivalent L1 VLPs, L2 capsid protein, and chimeric L1/L2 VLPs. Therapeutic HPV vaccine candidates have focused on enhancing T cell-mediated killing of HPV-transformed tumor cells, which constitutively express HPV-encoded proteins, E6 and E7. Several therapeutic HPV vaccines are in clinical trials.

EXPERT OPINION

Although progress is being made, cost remains an issue inhibiting the use of preventive HPV vaccines in countries that carry the majority of the cervical cancer burden. In addition, progression of therapeutic HPV vaccines through clinical trials may require combination strategies employing different therapeutic modalities. As research in the development of HPV vaccines continues, we may generate effective strategies to control HPV-associated malignancies.

Perspective for prophylaxis and treatment of cervical cancer: an immunological approach

As the second most common cause of cancer-related death in women, human papilloma virus (HPV) vaccines have been a major step in decreasing the morbidity and mortality associated with cervical cancer. An estimated 490,000 women are diagnosed with cervical cancer each year. Increasing knowledge of the HPV role in the etiology of cervical cancer has led to the development and introduction of HPV-based vaccines for active immunotherapy of cervical cancer. Immunotherapies directed at preventing HPV-persistent infections. These vaccines are already accessible for prophylaxis and in the near future, they will be available for the treatment of preexisting HPV-related neoplastic lesions.

Clinical applications of DNA vaccines: current progress

It was discovered almost 20 years ago that plasmid DNA, when injected into the skin or muscle of mice, could induce immune responses to encoded antigens. Since that time, there has since been much progress in understanding the basic biology behind this deceptively simple vaccine platform and much technological advancement to enhance immune potency. Among these advancements are improved formulations and improved physical methods of delivery, which increase the uptake of vaccine plasmids by cells; optimization of vaccine vectors and encoded antigens; and the development of novel formulations and adjuvants to augment and direct the host immune response. The ability of the current, or second-generation, DNA vaccines to induce more-potent cellular and humoral responses opens up this platform to be examined in both preventative and therapeutic arenas. This review focuses on these advances and discusses both preventive and immunotherapeutic clinical applications.

Prevention and treatment of papillomavirus-related cancers through immunization

Cervical and other anogenital cancers are initiated by infection with one of a small group of human papillomaviruses (HPV). Virus-like particle-based vaccines have recently been developed to prevent infection with two cancer-associated HPV genotypes (HPV16, HPV18) and have been ∼95% effective at preventing HPV-associated disease caused by these genotypes in virus-naive subjects. Although immunization induces virus-neutralizing antibody sufficient to prevent infection, persistence of antibody as measured by current assays does not appear necessary to maintain protection over time. Investigators have not identified a reliable surrogate immunological marker of protection against disease following immunization. The prophylactic vaccines are not therapeutic for existing infection. Trials of HPV-specific immunotherapy have shown some efficacy for existing disease, although animal modeling suggests that a combination of immunization and local enhancement of innate immunity may be necessary for optimal therapeutic outcome. HPV prophylactic vaccines are the first vaccines designed to prevent a human cancer and are the practical outcome of a global collaborative effort between basic and applied scientists, clinicians, and industry.

Safety and Immunogenicity of a Human Papillomavirus Peptide Vaccine (CIGB-228) in Women with High-Grade Cervical Intraepithelial Neoplasia: First-in-Human, Proof-of-Concept Trial

Objective. CIGB-228 is a novel therapeutic vaccine consisting of HLA-restricted HPV16 E7 epitope adjuvated with VSSP. This trial was designed to evaluate the toxicity, safety, immunogenicity, HPV clearance, and lesion regression. Methods. Seven women were entered. All were HLA-A2 positive, had biopsy-proven high-grade CIN, histologically positive for HPV16, and beared persistent postbiopsy lesions visible by digital colposcopy. HLA-A2 women with biopsy-proven high-grade CIN, HPV16-positive, and beared persistent postbiopsy lesions visible by digital colposcopy were vaccinated. One weekly injections of CIGB-228 vaccine was given for four weeks. Then, loop electrosurgical excision procedure (LEEP) of the transformation zone was performed. Study subjects were followed for 1 year after LEEP. Results. No toxicity beyond grade 1 was observed during and after the four vaccinations. Five of seven women had complete and partial regression. Cellular immune response was seen in all patients. HPV was cleared in three of the patients with complete response. Conclusion. CIGB-228 vaccination was well tolerated and capable to induce IFNγ-associated T-cell response in women with high-grade CIN. In several patients, lesion regression and HPV clearance were observed.

[Prophylactic and therapeutic vaccines against human papilloma virus]

Infection with human papilloma virus (HPV) has been identified as the cause of recurrent papillomatosis and of a subgroup of squamous cell carcinomas of the head and neck. A change in prevalence of these lesions, especially for oropharyngeal carcinoma, can be expected as a consequence of the introduction of prophylactic HPV vaccines for young women, targeting the most frequent high- and low-risk HPV subtypes. Vaccination for the major low-risk HPV types has proven to be highly effective against genital warts and activity against papillomatosis can be expected. The possibilities of prophylactic HPV vaccination as well as new developments and the rationale for therapeutic vaccines are discussed on the basis of the current literature.

Synthetic vehicles for DNA vaccination

DNA vaccination is an attractive immunization method able to induce robust cellular immune responses in pre-clinical models. However, clinical DNA vaccination trials performed thus far have resulted in marginal responses. Consequently, strategies are currently under development to improve the efficacy of DNA vaccines. A promising strategy is the use of synthetic particle formulations as carrier systems for DNA vaccines. This review discusses commonly used synthetic carriers for DNA vaccination and provides an overview of in vivo studies that use this strategy. Future recommendations on particle characteristics, target cell types and evaluation models are suggested for the potential improvement of current and novel particle delivery systems. Finally, hurdles which need to be tackled for clinical evaluation of these systems are discussed.

Therapeutic HPV DNA vaccines

It is now well established that most cervical cancers are causally associated with HPV infection. This realization has led to efforts to control HPV-associated malignancy through prevention or treatment of HPV infection. Currently, commercially available HPV vaccines are not designed to control established HPV infection and associated premalignant and malignant lesions. To treat and eradicate pre-existing HPV infections and associated lesions which remain prevalent in the U.S. and worldwide, effective therapeutic HPV vaccines are needed. DNA vaccination has emerged as a particularly promising form of therapeutic HPV vaccines due to its safety, stability and ability to induce antigen-specific immunity. This review focuses on improving the potency of therapeutic HPV vaccines through modification of dendritic cells (DCs) by [1] increasing the number of antigen-expressing/antigen-loaded DCs, [2] improving HPV antigen expression, processing and presentation in DCs, and [3] enhancing DC and T cell interaction. Continued improvement in therapeutic HPV DNA vaccines may ultimately lead to an effective DNA vaccine for the treatment of HPV-associated malignancies.

Combining T-cell vaccination and application of agonistic anti-GITR mAb (DTA-1) induces complete eradication of HPV oncogene expressing tumors in mice

We generated an adenovirus-based T-cell vaccine (Ad-p14) that reliably elicits T-cell responses to human papillomavirus (HPV) oncogenes of the 2 most common high-risk HPV serotypes. The artificial gene used to create the vaccine comprising 415 aa (1248 bp) was cloned by fusing 14 polymerase chain reaction fragments of HPV16 and HPV18 E6 and E7 oncogenes devoid of sequences with transforming potential. Although ensuring maximal biologic safety, the construct includes approximately 70% of the relevant T-cell epitopes. In a tumor model for cervical cancer (C3), therapeutic vaccination led to complete eradication in 100% of the mice. In a second model (TC1), it induced initial tumor mass reduction, but 90% of the animals showed delayed tumor progression. To further improve the therapeutic effect, vaccination was combined with systemic application of imiquimod, anti-CD4, alpha-interferon, or anti-GITR. Although adding alpha-interferon improved the therapeutic potential of Ad-p14 by 40%, the combination with anti-GITR resulted in complete and permanent eradication of all TC1 tumors. Ad-p14 has clinical potential for treating HPV-induced lesions, and the added effect of immune response modifiers stresses the importance of combined protocols for immunotherapy of malignant tumors.

Immunotherapy for cervical cancer: Research status and clinical potential

The high-risk types of human papillomavirus (HPV) have been found to be associated with most cervical cancers and play an essential role in the pathogenesis of the disease. Despite recent advances in preventive HPV vaccine development, such preventive vaccines are unlikely to reduce the prevalence of HPV infections within the next few years, due to their cost and limited availability in developing countries. Furthermore, preventive HPV vaccines may not be capable of treating established HPV infections and HPV-associated lesions, which account for high morbidity and mortality worldwide. Thus, it is important to develop therapeutic HPV vaccines for the control of existing HPV infection and associated malignancies. Therapeutic vaccines are quite different from preventive vaccines in that they require the generation of cell-mediated immunity, particularly T cell-mediated immunity, instead of the generation of neutralizing antibodies. The HPV-encoded early proteins, the E6 and E7 oncoproteins, form ideal targets for therapeutic HPV vaccines, since they are consistently expressed in HPV-associated cervical cancer and its precursor lesions and thus play crucial roles in the generation and maintenance of HPV-associated disease. Our review covers the various therapeutic HPV vaccines for cervical cancer, including live vector-based, peptide or protein-based, nucleic acid-based, and cell-based vaccines targeting the HPV E6 and/or E7 antigens. Furthermore, we review the studies using therapeutic HPV vaccines in combination with other therapeutic modalities and review the latest clinical trials on therapeutic HPV vaccines.

Perspectives for preventive and therapeutic HPV vaccines

Human Papillomavirus (HPV) has been associated with several human cancers, including cervical cancer, vulvar cancer, vaginal and anal cancer, and a subset of head and neck cancers. Thus effective vaccination against HPV provides an opportunity to reduce the morbidity and mortality associated with HPV. The Food and Drug Administration of the United States has approved two preventive vaccines to limit the spread of HPV. However, these are unlikely to impact upon HPV prevalence and cervical cancer rates for many years. Furthermore, preventive vaccines do not exert therapeutic effects on pre-existing HPV infections and HPV-associated lesions. In order to further impact upon the burden of HPV infections worldwide, therapeutic vaccines are being developed. These vaccines aim to generate a cell-mediated immune response to infected cells. This review discusses current preventive and therapeutic HPV vaccines and their future directions.

Human Immunodeficiency Virus and Human Papilloma Virus - why HPV-induced lesions do not spontaneously resolve and why therapeutic vaccination can be successful

HIV and HPV can both cause chronic infections and are acquired during sexual contact. HIV infection results in a progressive loss of CD4+ T cells that is associated with an increased prevalence of HPV infections, type-specific persistence and an increase in HPV-associated malignancies. On the one hand this illustrates the important role of HPV-specific CD4+ helper T-cell immunity, on the other it shows the Achilles heel of the HPV-specific immune response. The use of highly active antiretroviral therapy (HAART) results in a rapid reduction of HIV and a reconstitution of systemic CD4+ T-cell levels. The use of HAART thus has the potential to raise immunity to HPV but to the surprise of many, the incidence of HPV-induced diseases has increased rather than declined since the introduction of HAART. Here, the knowledge on how HPV-induced diseases develop in the face of a non-compromised immune system will be used to explain why the effect of HAART on HPV-induced diseases is modest at best. Furthermore, exciting new data in the field of therapeutic vaccines against HPV will be discussed as this may form a more durable and clinically successful therapeutic approach for the treatment of HPV-induced high-grade lesions in HIV-positive subjects on HAART.

Therapeutic vaccines against human papillomavirus and cervical cancer

Cervical cancer and its precursor intra-epithelial lesions are linked to infection by a subset of so-called "highrisk" human papillomavirus types, which are estimated to infect nearly four hundred million women worldwide. Two prophylactic vaccines have been commercialized recently targeting HPV16 and 18, the most prevalent viral types found in cervical cancer, which operate through induction of capsid-specific neutralizing antibodies. However, in patients with persistent infection these vaccines have not been found to protect against progression to neoplasia. Attempts are being made to develop therapeutic vaccines targeting nonstructural early viral proteins. Among these, E6 and E7 are the preferred targets, since they are essential for induction and maintenance of the malignant phenotype and are constitutively expressed by the transformed epithelial cells. Here are reviewed the most relevant potential vaccines based on HPV early antigens that have shown efficacy in preclinical models and that are being tested in clinical studies, which should determine their therapeutic capacity for eradicating HPV-induced premalignant and malignant lesions and cure cervical cancer.

Therapeutic HPV DNA vaccines

Human papillomavirus (HPV) has been associated with several human cancers, including cervical cancer, vulvar cancer, vaginal and anal cancer, and a subset of head and neck cancers. The identification of HPV as an etiological factor for HPV-associated malignancies creates the opportunity for the control of these cancers through vaccination. Currently, the preventive HPV vaccine using HPV virus-like particles has been proven to be safe and highly effective. However, this preventive vaccine does not have therapeutic effects, and a significant number of people have established HPV infection and HPV-associated lesions. Therefore, it is necessary to develop therapeutic HPV vaccines to facilitate the control of HPV-associated malignancies and their precursor lesions. Among the various forms of therapeutic HPV vaccines, DNA vaccines have emerged as a potentially promising approach for vaccine development due to their safety profile, ease of preparation and stability. However, since DNA does not have the intrinsic ability to amplify or spread in transfected cells like viral vectors, DNA vaccines can have limited immunogenicity. Therefore, it is important to develop innovative strategies to improve DNA vaccine potency. Since dendritic cells (DCs) are key players in the generation of antigen-specific immune responses, it is important to develop innovative strategies to modify the properties of the DNA-transfected DCs. These strategies include increasing the number of antigen-expressing/antigen-loaded DCs, improving antigen processing and presentation in DCs, and enhancing the interaction between DCs and T cells. Many of the studies on DNA vaccines have been performed on preclinical models. Encouraging results from impressive preclinical studies have led to several clinical trials.

Development of therapeutic HPV vaccines

At least 15% of human malignant diseases are attributable to the consequences of persistent viral or bacterial infection. Chronic infection with oncogenic human papillomavirus (HPV) types is a necessary, but insufficient, cause in the development of more cancers than any other virus. Currently available prophylactic vaccines have no therapeutic effect for established infection or for disease. Early disease is characterised by tissue sequestration. However, because a proportion of intraepithelial HPV-associated disease undergoes immune-mediated regression, the development of immunotherapeutic strategies is an opportunity to determine proof-of-principle for therapeutic vaccines. In this Review, we discuss recent progress in this field and priorities for future clinical investigations.

[Protection against uterine cervical cancer by HPV vaccines]

Research literature has definitively shown HPV to be a necessary cause of cervical cancer. HPV is highly prevalent in sexually active populations and its natural history is now traceable thanks to recent advances in technology. HPV-like particle can now be synthesized and assembled in vitro to constitute the major virion protein L1, and this technology has been exploited to produce HPV-L1-VLP vaccines. Now, HPV-related diseases can thus be prevented by commercially available HPV prophylactic vaccines such as Gardasil (recombinant HPV genotype 6/11/16/18) and Cervarix (recombinant HPV genotype 16/18). These advances have dramatically changed the administration of cervical cancer screening programs.

Polymeric Materials for Gene Delivery and DNA Vaccination

Gene delivery holds great potential for the treatment of many different diseases. Vaccination with DNA holds particular promise, and may provide a solution to many technical challenges that hinder traditional vaccine systems including rapid development and production and induction of robust cell-mediated immune responses. However, few candidate DNA vaccines have progressed past preclinical development and none have been approved for human use. This Review focuses on the recent progress and challenges facing materials design for nonviral DNA vaccine drug delivery systems. In particular, we highlight work on new polymeric materials and their effects on protective immune activation, gene delivery, and current efforts to optimize polymeric delivery systems for DNA vaccination.

Medical treatment of cervical intraepithelial neoplasia II, III: an update review

Cervical intraepithelial neoplasia (CIN) II, III is a preinvasive stage of squamous cell carcinoma of the uterine cervix. The standard treatment for CIN II, III consists of ablation and excision. However, nonsurgical treatment may be necessary for some women to preserve future reproductive potential. This review was conducted to summarize available published data on the efficacy and safety of medical treatment for CIN II, III. Based on existing studies, cyclooxygenase (COX)-2 inhibitors; indole-3-carbinol; and novel immunotherapy agents, including ZYC101a, MVA E2, and HspE7, have been observed as possessing therapeutic activity without any major treatment-related complications. These promising results provide important data for the future direction of clinical research.