Human Papillomavirus Vaccines and Prevention of Cervical Cancer

Framing technology challenges associated with improving cancer immunotherapies

Thought leader Jim Heath introduces the Lab on a Chip Immunotherapy thematic collection.

HPV-related head and neck squamous cell carcinoma: An update and review

This is a review of human papilloma virus (HPV)-related head and neck squamous cell carcinoma (HNSCC). The epidemiology, pathology, clinical features, and risk factors of HPV-related HNSCC are discussed. HPV vaccines are also discussed.

Delivery strategies to enhance oral vaccination against enteric infections

While the majority of human pathogens infect the body through mucosal sites, most licensed vaccines are injectable. In fact the only mucosal vaccine that has been widely used globally for infant and childhood vaccination programs is the oral polio vaccine (OPV) developed by Albert Sabin in the 1950s. While oral vaccines against Cholera, rotavirus and Salmonella typhi have also been licensed, the development of additional non-living oral vaccines against these and other enteric pathogens has been slow and challenging. Mucosal vaccines can elicit protective immunity at the gut mucosa, in part via antigen-specific secretory immunoglobulin A (SIgA). However, despite their advantages over the injectable route, oral vaccines face many hurdles. A key challenge lies in design of delivery strategies that can protect antigens from degradation in the stomach and intestine, incorporate appropriate immune-stimulatory adjuvants and control release at the appropriate gastrointestinal site. A number of systems including micro and nanoparticles, lipid-based strategies and enteric capsules have significant potential either alone or in advanced combined formulations to enhance intestinal immune responses. In this review we will outline the opportunities, challenges and potential delivery solutions to facilitate the development of improved oral vaccines for infectious enteric diseases.

Mucosal vaccine design and delivery

Mucosal surfaces are a major portal of entry for many human pathogens that are the cause of infectious diseases worldwide. Vaccines capable of eliciting mucosal immune responses can fortify defenses at mucosal front lines and protect against infection. However, most licensed vaccines are administered parenterally and fail to elicit protective mucosal immunity. Immunization by mucosal routes may be more effective at inducing protective immunity against mucosal pathogens at their sites of entry. Recent advances in our understanding of mucosal immunity and identification of correlates of protective immunity against specific mucosal pathogens have renewed interest in the development of mucosal vaccines. Efforts have focused on efficient delivery of vaccine antigens to mucosal sites that facilitate uptake by local antigen-presenting cells to generate protective mucosal immune responses. Discovery of safe and effective mucosal adjuvants are also being sought to enhance the magnitude and quality of the protective immune response.

Pathogenesis

Virus pathogenesis is a complex, variable, and relatively rare state. Like the course of a virus infection, pathogenesis is determined by the balance between host and virus factors. Not all the pathogenic symptoms seen in virus infections are caused directly by the virus but are side effects of the immune response. In the past few decades, molecular genetic analysis has contributed enormously in understanding the virus pathogenesis. In the chapter, three major aspects of virus pathogenesis are considered: direct cell damage resulting from virus replication, damage resulting from immune activation or suppression, and cell transformation caused by viruses. The chapter also discusses the mechanisms of cellular injury, virus-induced immunodeficiency, virus-related diseases, bacteriophages, and cell transformation by viruses, retroviruses, and DNA viruses. The chapter ends with a discussion of new pathogenic viruses that are being discovered all the time, and changes in human activities that have resulted in the emergence of new or previously unrecognized diseases.

The efficacy and safety of the quadrivalent human papillomavirus 6/11/16/18 vaccine gardasil

Human papillomavirus (HPV) infection causes cervical cancer, a significant portion of anal, genital, and oropharyngeal cancers, genital warts, and recurrent respiratory papillomatosis. In June 2006, a quadrivalent HPV-6/11/16/18 vaccine (Gardasil/Silgard) was licensed in the United States, and subsequently in the European Union (September 2006). It has since been approved in 121 countries, with >74 million doses distributed globally as of March 2011. As the incidence of HPV infection peaks 5-10 years after the onset of sexual activity, preadolescents and adolescents represent an appropriate target group to implement HPV vaccination programs so as to achieve the maximal public health benefit. In this article, we provide an overview of the prophylactic efficacy of the vaccine in young women who were found to be negative to at least one of the four vaccine HPV types, thus approximating sexually naive adolescents. Because adolescents are also at high risk for other infections which are preventable by currently available vaccines, the development of concurrent immunization strategies may lead to better compliance, thereby contributing to the overall goal of protection against preventable diseases. We also summarize concomitant administration studies with meningococcal, diphtheria, tetanus, and pertussis vaccines, which were conducted in adolescents aged 9-15 years. Prophylactic efficacy in other populations (males aged 16-26 years) is also summarized along with long-term safety and efficacy studies.

Emergency department management of sexually transmitted infections

Patients seeking treatment for sexually transmitted infections (STIs) account for a large number of emergency department (ED) visits per year. Despite the large volume of patients, STIs are often missed or treated inappropriately. Due to the high prevalence and incidence of STIs in the United States, it is important that emergency practitioners recognize symptoms consistent with STIs, and treat presumptively. This practice leads to overtreatment of STIs; however, when weighed against the public health risk and complications of untreated disease, empiric treatment is recommended. This article provides an overview of STIs encountered in the ED and recommendations for their treatment.

Predicting pediatricians' communication with parents about the human papillomavirus (hpv) vaccine: an application of the theory of reasoned action

This study examines the ability of the theory of reasoned action (TRA) and the theory of planned behavior (TPB) to predict whether or not pediatricians encourage parents to get their adolescent daughters vaccinated against the human papillomavirus (HPV). Four-hundred and six pediatricians completed a mail survey measuring attitudes, subjective norms, perceived behavioral control, intentions, and behavior. Results indicate that pediatricians have positive attitudes, subjective norms, and perceived behavioral control toward encouraging parents to get their daughters vaccinated, that they intend to regularly encourage parents to get their daughters vaccinated against HPV in the next 30 days, and that they had regularly encouraged parents to get their daughters vaccinated against HPV in the past 30 days (behavior). Though the data were consistent with both the TRA and TPB models, results indicate that perceived behavioral control adds only slightly to the overall predictive power of the TRA, suggesting that attitudes and norms may be more important targets for interventions dealing with this topic and audience. No gender differences were observed for any of the individual variables or the overall fit of either model. These findings have important theoretical and practical implications for the development of health communication messages targeting health care providers in general, and for those designed to influence pediatricians' communication with parents regarding the HPV vaccine in particular.

Four year efficacy of prophylactic human papillomavirus quadrivalent vaccine against low grade cervical, vulvar, and vaginal intraepithelial neoplasia and anogenital warts: randomised controlled trial

OBJECTIVES

To evaluate the prophylactic efficacy of the human papillomavirus (HPV) quadrivalent vaccine in preventing low grade cervical, vulvar, and vaginal intraepithelial neoplasias and anogenital warts (condyloma acuminata).

DESIGN

Data from two international, double blind, placebo controlled, randomised efficacy trials of quadrivalent HPV vaccine (protocol 013 (FUTURE I) and protocol 015 (FUTURE II)). The trials were to be 4 years in length, and the results reported are from final study data of 42 months' follow-up.

SETTING

Primary care centres and university or hospital associated health centres in 24 countries and territories around the world.

PARTICIPANTS

17 622 women aged 16-26 years enrolled between December 2001 and May 2003. Major exclusion criteria were lifetime number of sexual partners (>4), history of abnormal cervical smear test results, and pregnancy.

INTERVENTION

Three doses of quadrivalent HPV vaccine (for serotypes 6, 11, 16, and 18) or placebo at day 1, month 2, and month 6.

MAIN OUTCOME MEASURES

Vaccine efficacy against cervical, vulvar, and vaginal intraepithelial neoplasia grade I and condyloma in a per protocol susceptible population that included subjects who received all three vaccine doses, tested negative for the relevant vaccine HPV types at day 1 and remained negative through month 7, and had no major protocol violations. Intention to treat, generally HPV naive, and unrestricted susceptible populations were also studied.

RESULTS

In the per protocol susceptible population, vaccine efficacy against lesions related to the HPV types in the vaccine was 96% for cervical intraepithelial neoplasia grade I (95% confidence interval 91% to 98%), 100% for both vulvar and vaginal intraepithelial neoplasia grade I (95% CIs 74% to 100%, 64% to 100% respectively), and 99% for condyloma (96% to 100%). Vaccine efficacy against any lesion (regardless of HPV type) in the generally naive population was 30% (17% to 41%), 75% (22% to 94%), and 48% (10% to 71%) for cervical, vulvar, and vaginal intraepithelial neoplasia grade I, respectively, and 83% (74% to 89%) for condyloma.

CONCLUSIONS

Quadrivalent HPV vaccine provided sustained protection against low grade lesions attributable to vaccine HPV types (6, 11, 16, and 18) and a substantial reduction in the burden of these diseases through 42 months of follow-up.

TRIAL REGISTRATIONS

NCT00092521 and NCT00092534.

Vaccines and biosimilarity: a solution or a problem?

Biosimilarity is a significant issue for vaccines and a reasonable approach to this could facilitate licensing of follow-on products of similar design. However, the definitions and guideline criteria developed for similar versions of biotherapeutics may be too restrictive for vaccines, as the molecular composition of their active substances can rarely be defined precisely, and immunogenicity is an essential rather than an undesirable characteristic. Similarity in antigenic composition may be more relevant. The criteria that determine biosimilarity need more careful definition; superficial similarity may conceal significant differences in performance that can only be disclosed by careful clinical evaluation. These issues have been reviewed in detail for current types of bacterial and viral vaccines. For truly biosimilar products, limited clinical studies could be acceptable provided that they permit side-by-side comparison with the original product or another suitable reference. The prospect of the development of biosimilar products also emphasizes the need for improved regulatory tests capable of detecting subtle but biologically significant differences in vaccines. The need for an acceptable definition of biosimilarity and guidelines relevant to vaccines is emphasized.

Adolescent girls' attitudes on human papillomavirus vaccination

STUDY OBJECTIVE

The objective of the study was to assess the attitudes of adolescent girls on Human papillomavirus (HPV) vaccination and the impact of an information pamphlet on their attitude. Other factors that may affect their attitude were also studied.

DESIGN

Questionnaire survey.

SETTING

Pediatric and adolescent gynecology clinic.

PARTICIPANTS

250 adolescents aged 12 to 19 years.

INTERVENTIONS

Participants completed a questionnaire regarding their knowledge and attitudes towards HPV vaccination. Immediately following this, they read an information pamphlet on HPV vaccination. They then completed the same questionnaire again.

MAIN OUTCOME MEASURES

The attitude of the adolescents towards HPV vaccination.

RESULTS

Initially, 35% intended to receive the vaccination but after reading the information pamphlet, it rose to 69%. Their intention was positively correlated with their knowledge (P = 0.003), health belief (P < 0.001) and belief in who should receive the vaccine (P < 0.001) but negatively correlated with their belief that other people would approve of their vaccination (normative belief) (P < 0.001). There was a significant increase in their knowledge score (P < 0.001) after reading the pamphlet. Their health belief and belief in who should receive vaccine became more positive (P < 0.001), but the normative belief was more negative (P = 0.002) after reading.

CONCLUSION

69% of adolescent girls intended to receive HPV vaccination and their intention was improved by reading an information pamphlet. It was positively correlated with their knowledge, health belief, and belief in who should receive the vaccine, but negatively correlated with their normative belief.

Prophylactic HPV vaccines

Human papillomavirus (HPV) is one of the most common sexually transmitted diseases worldwide. Cervical and other anogenital cancers, cervical and anal intraepithelial neoplasia, genital warts, and recurrent respiratory papillomatosis are HPV associated diseases. Prophylactic HPV vaccines are composed of HPV L1 capsid protein that self-assemble into virus-like particles (VLPs) when expressed in recombinant systems. Two types of prophylactic vaccines are designed as a bivalent vaccine to protect against high-risk HPV types 16 and 18 and a quadrivalent vaccine designed to protect against HPV 16 and 18, and low-risk, genital wart-causing HPV 6 and 11. Proof-of-principle trials have suggested that intramuscular injections of VLPs result in strong adaptive immune responses that are capable of neutralizing subsequent natural infections. Recent research on the safety and efficacy of candidate prophylactic vaccines against HPV have shown very promising results with nearly 100% efficacy in preventing the development of persistent infections and cervical precancerous lesions in vaccinated individuals.

Prophylactic HPV vaccines: new interventions for cancer control

Human Papillomavirus (HPV) infection causes cervical cancer, a significant portion of anal, vulvar, vaginal, and oropharyngeal cancers, genital warts, and recurrent respiratory papillomatosis (RRP). HPV 16 and 18 cause 70-90% of HPV-related cancers whereas HPV 6 and 11 cause 90% of RRP and genital wart cases. Together these four types cause 30-50% of all cervical intraepithelial neoplasia such as those detected by Papinicalou screening. In June 2006, a quadrivalent HPV (6, 11, 16, 18) vaccine was licensed in the United States, and subsequently in the European Union (September 2006), both following expedited review. We describe the primary objectives of the quadrivalent HPV vaccine clinical trial program including studies in females aged 9-45 and males aged 9-26. Planned long-term efficacy and safety evaluations, as well as programs to evaluate vaccine impact on oropharyngeal cancer are also described.

A practical approach to warts in the emergency department

Although cutaneous warts are one of the most common skin conditions affecting children, their management can be challenging, especially in complex cases and even more so during a single emergency department encounter. Anogenital warts require particular attention because of their possible but nonspecific association with sexual abuse. This review will focus on cutaneous warts and anogenital warts, with a discussion of their recognition and treatment, especially in the emergency department. The medicolegal implications of anogenital warts in children are also reviewed.

Quadrivalent human papillomavirus vaccine

The lifetime risk of human papillomavirus (HPV) infection exceeds 50%. HPV infection causes >550,000 cases of cervical and anogenital cancer worldwide annually. Infection also causes precancerous lesions and genital warts. HPV types 16 and 18 cause approximately 70% of HPV-related cancers, and HPV types 6 and 11 cause approximately 90% of cases of genital warts. A quadrivalent vaccine for HPV types 6, 11, 16, and 18 (HPV 6/11/16/18) has been developed for prevention of cervical cancer, genital warts, and vulvar and vaginal precancerous lesions. Prophylactic vaccination of young women was 96%-100% effective in preventing HPV 6/11/16/18-related cervical and anogenital precancers and genital warts. Efficacy remained high for at least 5 years following vaccination. Postvaccination anti-HPV levels in adolescents were superior to those observed in women (the population in which efficacy was shown). Vaccination was generally well tolerated. The vaccine is licensed in >80 countries. It has been added to national vaccination programs, including that of the United States. Widespread use of HPV 6/11/16/18 vaccine is expected to greatly reduce the incidence of HPV-related cancers, precancers, and genital warts.

Vaccination with an adenoviral vector expressing calreticulin-human papillomavirus 16 E7 fusion protein eradicates E7 expressing established tumors in mice

BACKGROUND

Cervical cancer remains a leading cause of cancer-related mortality in women, particularly in developing countries. The causal association between genital human papilloma virus (HPV) infection and cervical cancer has been firmly established, and the oncogenic potential of certain HPV types has been clearly demonstrated. Vaccines targeting the oncogenic proteins, E6 and E7 of HPV-16 and -18 are the focus of current vaccine development. Previous studies have shown that calreticulin (CRT) enhances the MHC class I presentation of linked peptide/protein and may serve as an effective vaccination strategy for antigen-specific cancer treatment.

METHODS

Two replication-deficient adenoviruses, one expressing HPV-16 E7 (Ad-E7) and the other expressing CRT linked to E7 (Ad-CRT/E7), were assessed for their ability to induce cellular immune response and tested for prophylactic and therapeutic effects in an E7-expressing mouse tumor model.

RESULTS

Vaccination with Ad-CRT/E7 led to a dramatic increase in E7-specific T cell proliferation, interferon (IFN)-gamma-secretion, and cytotoxic activity. Immunization of mice with Ad-CRT/E7 was effective in preventing E7-expressing tumor growth, as well as eradicating established tumors with long-term immunological memory.

CONCLUSION

Vaccination with an adenoviral vector expressing CRT-E7 fusion protein represents an effective strategy for immunotherapy of cervical cancer in rodents, with possible therapeutic potential in clinical settings.

Assessing the introduction of universal human papillomavirus vaccination for preadolescent girls in The Netherlands

A persistent infection with human papillomavirus (HPV) is a prerequisite for the development of cervical cancer. Clinical trials with HPV-vaccines have been very successful in preventing persistent HPV16/18 infections, the two most oncogenic HPV-genotypes. We assessed the introduction of universal HPV-vaccination for preadolescent girls in the Dutch National Immunization Programme. Long-term vaccine efficacy, the need and extent of a catch-up programme for young women, and the impact of vaccination on the cervical cancer screening programme are major unresolved issues. Preliminary conservative estimates (80% vaccine efficacy and no effects on the screening programme, transmission rate, non-cervical cancer incidence, and cross protection) predict an acceptable cost-effectiveness ratio for universal vaccination of preadolescent girls.

Human papillomavirus vaccine: a new chance to prevent cervical cancer

Human papillomavirus (HPV) is a significant source of morbidity and mortality throughout the world and is the most common sexually transmitted infection in the United States. HPV is the primary etiologic agent of cervical cancer and dysplasia. Thus, cervical cancer and other HPV-associated malignancies might be prevented or treated by HPV vaccines. Recent research on the safety and efficacy of candidate prophylactic vaccines against HPV have shown very promising results, with nearly 100% efficacy in preventing the development of persistent infections and cervical dysplasia. Questions remain, however, concerning the duration of protection, vaccine acceptability, and feasibility of vaccine delivery in the developing world. Screening recommendations might also be modified based on the longer-term follow-up data and cost-effectiveness considerations, but some level of screening is likely to be required for decades following the implementation of vaccine programs.

A DNA vaccine constructed with human papillomavirus type 16 (HPV16) E7 and E6 genes induced specific immune responses

OBJECTIVE

Cervical cancer is found highly associated with human papillomaviruses type 16 (HPV16). HPV16 E6 and E7 oncogenes are important transforming genes which have become the main focus of anti-cervical cancer therapy. In this study, a recombinant DNA vaccine candidate, termed HPV16-DNA-E6E7, constructed with HPV16 E7 and E6 genes was generated and used to against HPV16-induced tumors.

METHODS

We inserted an E7 DNA fragment into E6 gene to produce a recombinant gene (E6E7-DNA). The E6E7-DNA gene was inserted into a mammalian expression vector, pcDNA 3.1+, to construct the DNA vaccine candidate. Animals (C57BL/6 mice) were immunized with the vaccine candidate with various concentrations (50 microg, 100 microg or 200 microg, respectively), and cytotoxicity measurement and tumor protection assay were carried out to examine the immunological effects of the vaccine candidate.

RESULTS

Immunization of with HPV16-E6E7-DNA induced HPV16-specific immune response and also conveyed protection against TC-1 induced tumor in vivo. A survival rate (90%) after 45 days of tumor challenge was observed. The animals injected with a higher dosage of the vaccine (200 microg) exhibited prolonged survival duration of more than 55 days. No transforming activity of the vaccine candidate was detected, as determined by focus formation and degradation of endogenous p53.

CONCLUSION

Our results demonstrated that the HPV16-E6E7-DNA compound might become a candidate for HPV16 precautionary and immunotherapy.

Recent advances in human papillomavirus vaccines

The human papillomavirus (HPV) is one of the most common sexually transmitted infections and the etiologic agent of cervical dysplasia and cancer. Recent research on the safety and efficacy of prophylactic vaccines against HPV has shown promising results with nearly 100% efficacy in preventing persistent infections and cervical dysplasia. Several approaches are being tested in therapeutic vaccine clinical trials whereby E6, E7, or both agents are administered in live viral vectors, as proteins, or in nucleic acid form. Cell-based therapeutic vaccines are also being tested. HPV vaccines have the potential to eradicate a major cancer and source of morbidity around the world.

A Virosomal Immunization Strategy against Cervical Cancer and Pre-Malignant Cervical Disease

In this study, we demonstrate that fusion-active virosomes, containing recombinant human papillomavirus type 16 (HPV16) E7 protein antigen, are capable of inducing a robust class I MHC-restricted cytotoxic T-lymphocyte (CTL) response against HPV-transformed tumour cells in a murine model system. Virosomes are reconstituted viral envelopes, which do not contain the genetic material of the native virus. During the reconstitution process, protein antigens can be encapsulated within the virosomes. In the present study, we used virosomes derived from influenza virus. These virosomes retain the cell binding and membrane fusion characteristics of native influenza virus, and have the capacity to deliver encapsulated antigens to the cytosol of antigen-presenting cells through fusion from within acidic endosomes. After immunization of mice with virosomes containing encapsulated HPV16 E7 protein, the animals developed a strong E7–specific CTL response as assessed by 51Cr release measurements and MHC tetramer staining of spleen cells. Immunization with E7–containing virosomes also resulted in E7-specific antibody responses.

In tumour challenge experiments, immunization of mice with E7-containing virosomes prevented tumour outgrowth in >70% of the animals. Thus, influenza-derived virosomes with encapsulated HPV E7 protein antigen act as an excellent vaccine delivery system for induction of cellular immunity against HPV-transformed cells and represent a promising immunotherapeutic vaccine for the treatment of (precursor lesions of) cervical cancer.

Prophylactic HPV vaccines: Reducing the burden of HPV-related diseases

HPV-associated diseases, such as cervical and other anogenital cancers, cervical and anal intraepithelial neoplasia, genital warts, and recurrent respiratory papillomatosis confer considerable morbidity and mortality, and are significant health care concerns. Successful vaccination strategies that protect against HPV infection are expected to substantially reduce HPV-related disease burden. Prophylactic HPV vaccines in late stages of clinical testing are composed of HPV L1 capsid protein that self-assemble into virus-like particles (VLPs) when expressed in recombinant systems. Proof-of-principle trials have suggested that intramuscular injections of VLPs results in strong adaptive immune responses, both B- and T-cell mediated, that are capable of neutralizing subsequent natural infections. Furthermore, phase 2 trials of a bivalent vaccine designed to protect against high-risk HPV types 16 and 18 and a quadrivalent vaccine designed to protect against HPV 16 and 18, and low-risk, genital wart-causing HPV 6 and 11 have demonstrated that VLP vaccines reduce the incidence of HPV-associated disease in vaccinated individuals. To derive the greatest public health benefit, HPV vaccines offering protection from cervical cancer and genital warts will, ideally, be administered prior to the initiation of sexual activity; therefore, educational initiatives will be essential to communicate the risks and adverse consequences of HPV infection and to foster widespread vaccine acceptance.

HPV vaccine development: A case study of prevention and politics

An analysis of the development of human papillomavirus (HPV) vaccines requires a fundamental comprehension of the underlying science of the technology, as well as an appreciation for the business issues essential to successful commercialization. Students analyzing this topic must consider scientific challenges related to the development of these vaccines, as well as the implications for their commercialization. This case study describes the evolution of our understanding of HPV infection and its causative link to cervical cancer, the establishment of viable HPV vaccine candidates, and various issues related to HPV vaccine implementation. Study questions for use in generating class discussion are provided.

Human papillomavirus type 16 E5 protein as a therapeutic target

Cervical cancer is a progressive disease with an onset of one to two decades on average. During the productive replication stage, the Human papillomavirus (HPV) genome is maintained episomally in the infected cervical epithelium and early gene products, including E5, are expressed. Therefore, E5 has a potential to contribute to the HPV-associated carcinogenic process. In invasive malignancies, the HPV genomes are commonly integrated into the host genome, and E6 and E7 genes remain intact. However, the E5 is lost or, if present, under-expressed as compared with the E6 and E7 proteins. This suggests that E5 may play a critical role in the genesis of cervical cancer but less of a role in its persistence or progression. In the initiation of neoplasia and the premalignant stage, there are fewer malignant cells than in the invasive malignancies. Moreover, cells in the invasive malignant stage are found to have a very low level of MHC class I and II, which could hamper the presentation of the antigen and lead to a decreased immune response. Since the E5 protein is likely to play a role during the early tumorigenesis stage, a therapeutic vaccine to target and eliminate the E5-expressing cells may be a good strategy to prevent premalignant lesions from progressing toward invasive cervical cancers. This paper provides an overview of HPV-induced cervical carcinogenesis and strategies for designing prophylactic and therapeutic vaccines to prevent and cure the cervical cancer. In particular, focus will be on the rationale of targeting the E5 protein to develop therapeutic vaccines.

Regression of papilloma high-grade lesions (CIN 2 and CIN 3) is stimulated by therapeutic vaccination with MVA E2 recombinant vaccine

Human papillomavirus (HPV) is the etiologic agent for cervical cancer. In Mexico, a women dies every 2 h, and since 1990 the statistics have shown that the numbers of deaths are increasing. We conducted a phase II clinical trial to evaluate the potential use of the MVA E2 recombinant vaccinia virus in treating high-grade lesions (CIN 2 and CIN 3) associated with oncogenic papillomavirus. Fifty-four female patients with high degree lesions were treated either with an MVA E2 therapeutic vaccine or with conization. Thirty-four women received the therapeutic vaccine, at a total of 10(7) virus particles per dose injected directly into the uterus once every week over a 6-week period. Twenty control patients were treated with conization. By colposcopy, 19 patients out of 34 showed no lesion, in three patients the lesions were reduced by 85-90%, in eight other lesions had reduced by 60%, and in four more patients, they were reduced by 25%. Histological analysis showed total elimination of high-grade lesions in 20 out of 34 patients after treatment with MVA E2. Eleven patients had a 50% reduction in lesion size. In two other patients, the lesion was reduced to CIN 2 and in one more patient the lesion was reduced to low grade (CIN 1). All patients developed antibodies against the MVA E2 vaccine, and generated a specific cytotoxic response against papilloma-transformed cells. DNA viral load was significantly reduced in MVA E2-treated patients. Conization eliminated the lesions in 80% of the patients, but patients did not develop cytotoxic activity specific against cancer cells and did not eliminate the papillomavirus. In addition, three patients treated with conization had recurrence of lesions 1 year later. These results show that therapeutic vaccination with MVA E2 proved to be very effective in stimulating the immune system against papillomavirus, and in generating regression of high-grade lesion.

Harnessing the power of prevention: human papillomavirus vaccines

Human papillomavirus (HPV) infection and HPV-associated diseases pose a considerable health care burden in the United States. The morbidity and mortality associated with HPV infection and HPV-associated diseases, ranging from genital warts to cervical cancer, have prompted both the use of screening measures to monitor HPV infection and the development of numerous treatment modalities to address its clinical sequelae. Although screening programs have dramatically reduced the incidence of cervical cancer through early detection and treatment, this devastating illness, which frequently affects women of reproductive age, remains a major public health concern. Prophylactic vaccines that prevent HPV infection have proved to be safe, well tolerated, highly efficacious, and induce long-lasting immunity to HPV. Multivalent vaccines that protect against the most common disease-causing HPV types should significantly reduce the morbidity and mortality associated with HPV.

Human Papillomavirus Quadrivalent (types 6, 11, 16, 18) Recombinant Vaccine (Gardasil??)

Human papillomavirus (HPV) quadrivalent recombinant vaccine is a mixture of virus-like particles derived from the L1 capsid proteins of HPV types 6, 11, 16 and 18. It is administered intramuscularly in a three-dose regimen, with the initial injection followed by subsequent doses at months 2 and 6. The vaccine is indicated for use in the prevention of cervical cancer, vulvar and vaginal precancer and cancers, precancerous lesions and genital warts associated with HPV types 6, 11, 16 or 18 infection in adolescents and young women. The quadrivalent vaccine has demonstrated good immunogenicity in young women (16-26 years) and male and female adolescents (aged 9-15 years), inducing high and persistent anti-HPV antibody titres. In a randomised phase III trial designed to bridge efficacy in young women to adolescents (using immunogenicity as a surrogate), the quadrivalent HPV vaccine in adolescents was at least as immunogenic as that in young women. In randomised, double-blind, placebo-controlled trials in >20 000 young women (aged 16-26 years), the vaccine was highly effective in preventing cervical dysplasia of any grade and external genital lesions related to HPV types 6, 11, 16 and 18 infection. These women were followed up for an average of 2 years.black triangle The vaccine was well tolerated, with injection-site reactions and fever being the most common vaccine-related adverse events.

Optimization and validation of a multiplexed luminex assay to quantify antibodies to neutralizing epitopes on human papillomaviruses 6, 11, 16, and 18

A human papillomavirus (HPV) multiplexed competitive Luminex immunoassay first described by Opalka et al. (D. Opalka, C. E. Lachman, S. A. MacMullen, K. U. Jansen, J. F. Smith, N. Chirmule, and M. T. Esser, Clin. Diagn. Lab. Immunol. 10:108--15, 2003) was optimized and validated for use in epidemiology studies and vaccine clinical trials. Optimization increased both the analytical sensitivity and the clinical specificity of the assay to more effectively discriminate the low-titer antibody response of HPV-infected persons from noninfected individuals. The characteristics of the assay that were optimized included monoclonal antibody (MAb) specificity, scaling up the conjugation of virus-like particles (VLPs) to microspheres, VLP concentration, MAb concentration, sample matrix, sample dilution, incubation time, heat inactivation of sample sera, and detergent effects on assay buffer. The assay was automated by use of a TECAN Genesis Workstation, thus improving assay throughput, reproducibility, and operator safety. Following optimization, the assay was validated using several distinct serum panels from individuals determined to be at low and high risk for HPV infection. The validated assay was then used to determine the clinical serostatus cutoff. This high-throughput assay has proven useful for performing epidemiology studies and evaluating the efficacy of prophylactic HPV vaccines.

Vaccines against human papillomavirus and cervical cancer: promises and challenges

Cervical cancer and precancerous lesions of the genital tract are major threats to the health of women worldwide. The introduction of screening tests to detect cervical cancer precursor lesions has reduced cervical cancer rates in the developed world, but not in developing countries. Human papillomavirus (HPV) is the primary etiologic agent of cervical cancer and dysplasia. Thus, cervical cancer and other HPV-associated malignancies might be prevented or treated by HPV vaccines. Two vaccine strategies have been developed. First, prevention of HPV infection through induction of capsid-specific neutralizing antibodies has been studied in clinical trials. However, because the capsid proteins are not expressed at detectable levels by infected basal keratinocytes or in HPV-transformed cells, a second approach of developing therapeutic vaccines by targeting nonstructural early viral antigens has also been developed. Because two HPV oncogenic proteins, E6 and E7, are critical to the induction and maintenance of cellular transformation and are coexpressed in the majority of HPV-containing carcinomas, most therapeutic vaccines target one or both of these gene products. A variety of approaches is being tested in therapeutic vaccine clinical trials, whereby E6 and/or E7 are administered in live vectors, as peptides or protein, in nucleic acid form, or in cell-based vaccines. The paradigm of preventing HPV infection through vaccination has been tested, and two vaccines are currently in phase III clinical trials. However, current therapeutic vaccine trials are less mature with respect to disease clearance. A number of approaches have shown significant therapeutic benefit in preclinical papillomavirus models and await testing in patient populations to determine the most effective curative strategy.

Clinical Trial Results of a HER2/neu (E75) Vaccine to Prevent Recurrence in High-Risk Breast Cancer Patients

Purpose

E75 is an immunogenic peptide from the HER2/neu protein that is highly expressed in breast cancer. We are conducting a clinical trial of an E75 + granulocyte-macrophage colony-stimulating factor vaccine to assess safety, immunologic response, and the prevention of clinical recurrences in patients with disease-free, node-positive breast cancer (NPBC).

Patients and Methods

Fifty-three patients with NPBC were enrolled and HLA typed. HLA-A2+ patients (n = 24) were vaccinated, and HLA-A2− patients (n = 29) are observed prospectively as clinical controls. Local/systemic toxicities, immunologic responses, and time to recurrence are being measured.

Results

Only minor toxicities have occurred (one grade 3 [4%]). All patients have demonstrated clonal expansion of E75-specific CD8+T cells that lysed HER2/neu-expressing tumor cells. An optimal dosage and schedule have been established. Patients have developed delayed-type hypersensitivity reactions to E75 postvaccination compared with controls (33 v 7 mm; P < .01). HLA-A2+ patients have been found to have larger, more poorly differentiated, and more hormonally insensitive tumors compared to HLA-A2− patients. Despite this, the only two deaths have occurred in the control group. The disease-free survival in the vaccinated group is 85.7% compared to 59.8% in the controls at 22 months' median follow-up with a recurrence rate of 8% compared to 21%, respectively (P < .19). Median time to recurrence in the vaccinated patients was prolonged (11 v 8 months), and recurrence correlated with a weak delayed-type hypersensitivity response.

Conclusion

This HER2/neu (E75) vaccine is safe and effective in eliciting a peptide-specific immune response in vivo. Induced HER2/neu immunity seems to reduce the recurrence rate in patients with NPBC.

HPV infection in adolescents: natural history, complications, and indicators for viral typing

Human papillomavirus (HPV) is the most common sexually transmitted disease in both men and women. Prevalence rates are the highest for adolescents. Despite the high prevalence rates, sequelae of genital warts, dysplasia, and cancer are rare developments. Knowledge about the natural history, virology, and cancerous transformation has lead to improved viral detection, including the use of HPV DNA detection tests, screening efforts for HPV-related precancerous and cancerous lesions, and clinical interventions and treatments, including both therapeutic and prophylactic vaccinations.

Vaccination against multiple HPV types

Vaccines against the most common human papillomavirus (HPV) types are currently under development. Epidemiologic data suggest that the transmission dynamics of different HPV types are not independent. Some studies indicate that interactions among HPV types are synergistic, where infection with one type facilitates concurrent or subsequent infection with another HPV type. Other studies point to antagonistic interference among HPV types. Here we develop a mathematical model to explore how these interactions may either enhance or diminish the effectiveness of vaccination programs designed to reduce the prevalence of the HPV types associated with cervical cancer. We analyze the local stability of the infection-free and boundary equilibria and characterize the conditions leading to a coexistence equilibrium. We also illustrate the results with numerical simulations using realistic model parameters. We show that if interactions among HPV types are synergistic, mass vaccination may reduce the prevalence of types that are not even included in the vaccine.

Protection of beagle dogs from mucosal challenge with canine oral papillomavirus by immunization with recombinant adenoviruses expressing codon-optimized early genes

Replication-deficient adenoviral (rAd5) vaccines containing codon-optimized E1, E2, E4, and E7 genes of canine oral papillomavirus (COPV) were tested singly or in combination to determine which vaccines could protect against mucosal challenge with COPV. In three studies, groups of 4-6 beagle dogs were immunized subcutaneously (s.c.) with 10(11) rAd5 at 8-10 weeks and 4-6 weeks prior to challenge with infectious COPV particles at multiple oral mucosal sites. Control dogs were immunized with equivalent doses of rAd5 expressing human papillomavirus (HPV) type 16 L1 (rAd5-HPV-16 L1). In the first study, complete protection from COPV-induced papillomas was achieved by immunization with rAd5 vaccine combinations expressing either E1 + E2 or E1 + E2 + E4 + E7; whereas two of six dogs immunized with rAd5-E4 + rAd5-E7 and six of six rAd5-HPV16-L1-immunized control dogs developed oral papillomas. In two subsequent studies, rAd5-E1 and rAd5-E2 vaccines were tested singly or in combination to assess levels of protective immunity to COPV challenge. Subcutaneous immunization with either one or two doses of rAd5 expressing the COPV E1 and E2 genes could protect > 90% of challenged dogs from wart formation. In contrast, all eight dogs immunized with rAd5-HPV-16 L1 developed papillomas at multiple sites. Protection was accompanied by significant IFN-gamma responses to COPV E1 and E2 peptides. Partial protection was conferred by two immunizations with either rAd5-E1 (6 of 9 protected) or rAd5-E2 (8 of 9 protected). These data indicate that rAd5 expressing papillomavirus E1 and E2 proteins can induce strong protective responses even in outbred populations under practical immunization conditions.

Immune response in cervical dysplasia induced by human papillomavirus: the influence of human immunodeficiency virus-1 co-infection - review

Human immunodeficiency virus (HIV-1) has become an important risk factor for human papillomavirus (HPV) infection and the development of HPV associated lesions in the female genital tract. HIV-1 may also increase the oncogenicity of high risk HPV types and the activation of low risk types. The Center for Disease Control and Prevention declared invasive cervical cancer an acquired immunodeficiency virus (AIDS) defining illness in HIV positive women. Furthermore, cervical cancer happens to be the second most common female cancer worldwide. The host's local immune response plays a critical factor in controlling these conditions, as well as in changes in the number of professional antigen-presenting cells, cytokine, and MHC molecules expression. Also, the production of cytokines may determine which arm of the immune response will be stimulated and may influence the magnitude of immune protection. Although there are many studies describing the inflammatory response in HPV infection, few data are available to demonstrate the influence of the HIV infection and several questions regarding the cervical immune response are still unknown. In this review we present a brief account of the current understanding of HIV/HPV co-infection, emphasizing cervical immune response.

Efficacy of a bivalent L1 virus-like particle vaccine in prevention of infection with human papillomavirus types 16 and 18 in young women: a randomised controlled trial

BACKGROUND

Vaccination against the most common oncogenic human papillomavirus (HPV) types, HPV-16 and HPV-18, could prevent development of up to 70% of cervical cancers worldwide. We did a randomised, double-blind, controlled trial to assess the efficacy, safety, and immunogenicity of a bivalent HPV-16/18 L1 virus-like particle vaccine for the prevention of incident and persistent infection with these two virus types, associated cervical cytological abnormalities, and precancerous lesions.

METHODS

We randomised 1113 women between 15-25 years of age to receive three doses of either the vaccine formulated with AS04 adjuvant or placebo on a 0 month, 1 month, and 6 month schedule in North America and Brazil. Women were assessed for HPV infection by cervical cytology and self-obtained cervicovaginal samples for up to 27 months, and for vaccine safety and immunogenicity.

FINDINGS

In the according-to-protocol analyses, vaccine efficacy was 91.6% (95% CI 64.5-98.0) against incident infection and 100% against persistent infection (47.0-100) with HPV-16/18. In the intention-to-treat analyses, vaccine efficacy was 95.1% (63.5-99.3) against persistent cervical infection with HPV-16/18 and 92.9% (70.0-98.3) against cytological abnormalities associated with HPV-16/18 infection. The vaccine was generally safe, well tolerated, and highly immunogenic.

INTERPRETATION

The bivalent HPV vaccine was efficacious in prevention of incident and persistent cervical infections with HPV-16 and HPV-18, and associated cytological abnormalities and lesions. Vaccination against such infections could substantially reduce incidence of cervical cancer.