Longer term efficacy of a prophylactic monovalent human papillomavirus type 16 vaccine

The relation between human papillomavirus (HPV) and oropharyngeal cancer: a review

Oropharyngeal squamous cell carcinomas (OPSCC) represent a major public health challenge. In 2020, the international agency for research on cancer (IARC) recorded 98,421 cases of OPSCC worldwide. Over the past decade, the epidemiological profile of patients with OPSCC has shifted, mainly due to a change in etiological factors. Previously, alcohol and tobacco were considered the primary contributors, but the human papillomavirus (HPV) is now recognized as the leading cause of these tumors. This study aimed to conduct a literature review on the relationship between OPSCC and HPV for the general practitioner. The review examined the primary clinical differences between HPV⁺ and HPV^- OPSCC, their prognosis and treatment. In addition, the various HPV diagnostic methods were analyzed. Although there is a vast amount of literature on HPV, this review is unique in its ability to present the key information in an organized and accessible way and enables healthcare professionals to gain a better understanding of the relationship between HPV and oropharyngeal cancer. This, in turn, can contribute to the prevention of various cancers caused by the HPV virus, including oropharyngeal cancer.

Data-Related Challenges in Cost-Effectiveness Analyses of Vaccines

Cost-effectiveness analyses (CEAs) are often prepared to quantify the expected economic value of potential vaccination strategies. Estimated outcomes and costs of vaccination strategies depend on numerous data inputs or assumptions, including estimates of vaccine efficacy and disease incidence in the absence of vaccination. Limitations in epidemiologic data can meaningfully affect both CEA estimates and the interpretation of those results by groups involved in vaccination policy decisions. Developers of CEAs should be transparent with regard to the ambiguity and uncertainty associated with epidemiologic information that is incorporated into their models. We describe selected data-related challenges to conducting CEAs for vaccination strategies, including generalizability of estimates of vaccine effectiveness, duration and functional form of vaccine protection that can change over time, indirect (herd) protection, and serotype replacement. We illustrate how CEA estimates can be sensitive to variations in specific epidemiologic assumptions, with examples from CEAs conducted for the USA that assessed vaccinations against human papillomavirus and pneumococcal disease. These challenges are certainly not limited to these two case studies and may be relevant to other vaccines.

The Efficacy of the Quadrivalent Human Papillomavirus Vaccine in Girls and Women Living With Human Immunodeficiency Virus

BACKGROUND

Human papillomavirus (HPV) vaccination is safe and efficacious in women without human immunodeficiency virus (HIV). Although good immunogenicity has been observed in women living with HIV (WLWH), efficacy data in this population are needed.

METHODS

We enrolled 420 females aged ≥9 years (range, 9-65) living with HIV. Participants were to receive 3 doses of qHPV vaccine (0/2/6 months). The main endpoint was vaccine failure (ie, incident persistent qHPV infection, cervical intraepithelial neoplasia of grade 2 or higher [CIN2+], or genital warts). We compared these rates to published rates in vaccinated and unvaccinated women without HIV as well as unvaccinated WLWH.

RESULTS

Among 279 eligible women, median follow-up was 2 years. In the intention-to-treat population, the incidence rate (IR) of persistent qHPV (HPV6/11/16/18) was 2.3 per 100 person-years (/100PY) (95% confidence interval [CI], 1.1-4.1), and IR of genital warts was 2.3/100PY (95% CI, 1.2-4.1). In the per-protocol efficacy population, IR of persistent qHPV was 1.0/100PY (95% CI, 0.3-2.6) and of genital warts was 1.0/100PY (95% CI, 0.3-2.5). No cases of CIN2+ occurred. Reported rates of qHPV-related infection and disease within vaccinated women without HIV, unvaccinated women without HIV, and vaccinated WLWH: 0.1 (95% CI, 0.02-0.03), 1.5 (95% CI, 1.1-2.0), and 1.2 (95% CI, 0.2-3.4) /100PY, respectively. The rate of persistent qHPV among vaccinated WLWH was lower than among unvaccinated WLWH (2.3 vs 6.0/100PY).

CONCLUSIONS

Vaccinated WLWH may be at higher risk for vaccine failure than vaccinated women without HIV. However, overall rates of vaccine failure were low, and rates of persistent qHPV were lower than in unvaccinated WLWH.

Efficacy and safety of prophylactic HPV vaccines. A Cochrane review of randomized trials

INTRODUCTION

Recently, the evidence on efficacy and safety of prophylactic HPV vaccines derived from randomized trials was published in the Cochrane database of Systematic reviews. A summary of this Cochrane review is presented below.

AREAS COVERED

Only trials involving mono-, bi-, and quadrivalent HPV vaccines were included. Trials evaluating the nonavalent vaccine were excluded since women in the control group received the quadrivalent vaccine. Main efficacy outcomes were: histologically confirmed cervical precancer lesions distinguishing those associated with vaccine HPV types and any cervical precancer. Exposure groups were: women aged: 15-26 or 24-45 years being initially negative for high-risk HPV (hrHPV) or negative for the vaccine types and women unselected by HPV status.

EXPERT COMMENTARY

All evaluated vaccines offered excellent protection against cervical intraepithelial neoplasia of grade 2 or 3 (CIN2 or CIN3) and adenocarcinoma in situ associated with HPV16/18 infection in young women who were not initially infected with hrHPV or HPV16/18. Vaccine efficacy was lower when all women regardless of HPV DNA status at enrollment were included. In young women, HPV vaccination protected also against any cervical precancer but the magnitude of protection was lower than against HPV16/18 associated cervical precancer. Vaccine efficacy was lower in mid-adult (aged 24-45 years) women. No protection against cervical precancer was found in mid-adult women unselected by HPV DNA status at enrollment. Trials were not empowered to address protection against cervical cancer. Occurrence of severe adverse events or adverse pregnancy outcomes was not significantly higher in recipients of HPV vaccines than in women included in the control arms.

Prophylactic vaccination against human papillomaviruses to prevent cervical cancer and its precursors

BACKGROUND

Persistent infection with high-risk human papillomaviruses (hrHPV) types is causally linked with the development of cervical precancer and cancer. HPV types 16 and 18 cause approximately 70% of cervical cancers worldwide.

OBJECTIVES

To evaluate the harms and protection of prophylactic human papillomaviruses (HPV) vaccines against cervical precancer and HPV16/18 infection in adolescent girls and women.

SEARCH METHODS

We searched MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL) and Embase (June 2017) for reports on effects from trials. We searched trial registries and company results' registers to identify unpublished data for mortality and serious adverse events.

SELECTION CRITERIA

Randomised controlled trials comparing efficacy and safety in females offered HPV vaccines with placebo (vaccine adjuvants or another control vaccine).

DATA COLLECTION AND ANALYSIS

We used Cochrane methodology and GRADE to rate the certainty of evidence for protection against cervical precancer (cervical intraepithelial neoplasia grade 2 and above [CIN2+], CIN grade 3 and above [CIN3+], and adenocarcinoma-in-situ [AIS]), and for harms. We distinguished between the effects of vaccines by participants' baseline HPV DNA status. The outcomes were precancer associated with vaccine HPV types and precancer irrespective of HPV type. Results are presented as risks in control and vaccination groups and risk ratios (RR) with 95% confidence intervals in brackets.

MAIN RESULTS

We included 26 trials (73,428 participants). Ten trials, with follow-up of 1.3 to 8 years, addressed protection against CIN/AIS. Vaccine safety was evaluated over a period of 6 months to 7 years in 23 studies. Studies were not large enough or of sufficient duration to evaluate cervical cancer outcomes. All but one of the trials was funded by the vaccine manufacturers. We judged most included trials to be at low risk of bias. Studies involved monovalent (N = 1), bivalent (N = 18), and quadrivalent vaccines (N = 7). Most women were under 26 years of age. Three trials recruited women aged 25 and over. We summarize the effects of vaccines in participants who had at least one immunisation.Efficacy endpoints by initial HPV DNA statushrHPV negativeHPV vaccines reduce CIN2+, CIN3+, AIS associated with HPV16/18 compared with placebo in adolescent girls and women aged 15 to 26. There is high-certainty evidence that vaccines lower CIN2+ from 164 to 2/10,000 (RR 0.01 (0 to 0.05)) and CIN3+ from 70 to 0/10,000 (RR 0.01 (0.00 to 0.10). There is moderate-certainty evidence that vaccines reduce the risk of AIS from 9 to 0/10,000 (RR 0.10 (0.01 to 0.82).HPV vaccines reduce the risk of any CIN2+ from 287 to 106/10,000 (RR 0.37 (0.25 to 0.55), high certainty) and probably reduce any AIS lesions from 10 to 0/10,000 (RR 0.1 (0.01 to 0.76), moderate certainty). The size of reduction in CIN3+ with vaccines differed between bivalent and quadrivalent vaccines (bivalent: RR 0.08 (0.03 to 0.23), high certainty; quadrivalent: RR 0.54 (0.36 to 0.82), moderate certainty). Data in older women were not available for this comparison.HPV16/18 negativeIn those aged 15 to 26 years, vaccines reduce CIN2+ associated with HPV16/18 from 113 to 6 /10,000 (RR 0.05 (0.03 to 0.10). In women 24 years or older the absolute and relative reduction in the risk of these lesions is smaller (from 45 to 14/10,000, (RR 0.30 (0.11 to 0.81), moderate certainty). HPV vaccines reduce the risk of CIN3+ and AIS associated with HPV16/18 in younger women (RR 0.05 (0.02 to 0.14), high certainty and RR 0.09 (0.01 to 0.72), moderate certainty, respectively). No trials in older women have measured these outcomes.Vaccines reduce any CIN2+ from 231 to 95/10,000, (RR 0.41 (0.32 to 0.52)) in younger women. No data are reported for more severe lesions.Regardless of HPV DNA statusIn younger women HPV vaccines reduce the risk of CIN2+ associated with HPV16/18 from 341 to 157/10,000 (RR 0.46 (0.37 to 0.57), high certainty). Similar reductions in risk were observed for CIN3+ associated with HPV16/18 (high certainty). The number of women with AIS associated with HPV16/18 is reduced from 14 to 5/10,000 with HPV vaccines (high certainty).HPV vaccines reduce any CIN2+ from 559 to 391/10,000 (RR 0.70 (0.58 to 0.85, high certainty) and any AIS from 17 to 5/10,000 (RR 0.32 (0.15 to 0.67), high certainty). The reduction in any CIN3+ differed by vaccine type (bivalent vaccine: RR 0.55 (0.43 to 0.71) and quadrivalent vaccine: RR 0.81 (0.69 to 0.96)).In women vaccinated at 24 to 45 years of age, there is moderate-certainty evidence that the risks of CIN2+ associated with HPV16/18 and any CIN2+ are similar between vaccinated and unvaccinated women (RR 0.74 (0.52 to 1.05) and RR 1.04 (0.83 to 1.30) respectively). No data are reported in this age group for CIN3+ or AIS.Adverse effectsThe risk of serious adverse events is similar between control and HPV vaccines in women of all ages (669 versus 656/10,000, RR 0.98 (0.92 to 1.05), high certainty). Mortality was 11/10,000 in control groups compared with 14/10,000 (9 to 22) with HPV vaccine (RR 1.29 [0.85 to 1.98]; low certainty). The number of deaths was low overall but there is a higher number of deaths in older women. No pattern in the cause or timing of death has been established.Pregnancy outcomesAmong those who became pregnant during the studies, we did not find an increased risk of miscarriage (1618 versus 1424/10,000, RR 0.88 (0.68 to 1.14), high certainty) or termination (931 versus 838/10,000 RR 0.90 (0.80 to 1.02), high certainty). The effects on congenital abnormalities and stillbirths are uncertain (RR 1.22 (0.88 to 1.69), moderate certainty and (RR 1.12 (0.68 to 1.83), moderate certainty, respectively).

AUTHORS' CONCLUSIONS

There is high-certainty evidence that HPV vaccines protect against cervical precancer in adolescent girls and young women aged 15 to 26. The effect is higher for lesions associated with HPV16/18 than for lesions irrespective of HPV type. The effect is greater in those who are negative for hrHPV or HPV16/18 DNA at enrolment than those unselected for HPV DNA status. There is moderate-certainty evidence that HPV vaccines reduce CIN2+ in older women who are HPV16/18 negative, but not when they are unselected by HPV DNA status.We did not find an increased risk of serious adverse effects. Although the number of deaths is low overall, there were more deaths among women older than 25 years who received the vaccine. The deaths reported in the studies have been judged not to be related to the vaccine. Increased risk of adverse pregnancy outcomes after HPV vaccination cannot be excluded, although the risk of miscarriage and termination are similar between trial arms. Long-term of follow-up is needed to monitor the impact on cervical cancer, occurrence of rare harms and pregnancy outcomes.

Human Papillomavirus and Its Testing Assays, Cervical Cancer Screening, and Vaccination

Human papillomavirus (HPV) was found to be the causative agent for cervical cancer in the 1980s with almost 100% of cervical cancer cases testing positive for HPV. Since then, many studies have been conducted to elucidate the molecular basis of HPV, the mechanisms of carcinogenesis of the virus, and the risk factors for HPV infection. Traditionally, the Papanicolaou test was the primary screening method for cervical cancer. Because of the discovery and evolving understanding of the role of HPV in cervical dysplasia, HPV testing has been recommended as a new method for cervical cancer screening by major professional organizations including the American Cancer Society, American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology. In order to detect HPV infections, many sensitive and specific HPV assays have been developed and used clinically. Different HPV assays with various principles have shown their unique advantages and limitations. In response to a clear causative relationship between high-risk HPV and cervical cancer, HPV vaccines have been developed which utilize virus-like particles to create an antibody response for the prevention of HPV infection. The vaccines have been shown in long-term follow-up studies to be effective for up to 8 years; however, how this may impact screening for vaccinated women remains uncertain. In this chapter, we will review the molecular basis of HPV, its pathogenesis, and the epidemiology of HPV infection and associated cervical cancer, discuss the methods of currently available HPV testing assays as well as recent guidelines for HPV screening, and introduce HPV vaccines as well as their impact on cervical cancer screening and treatments.

Naprotecnología: ciencia y persona en la infección por el virus del papiloma humano (VPH) en mujeres y preadolescencentes

En la actualidad hay suficiente evidencia científica que relaciona directamente adquisición, exposición y prevalencia del virus del papiloma humano (VPH) con el cáncer del cuello de uterino. Por ello, el artículo aborda el VPH en la mujer teniendo en cuenta la naprotecnología, que permite conjugar evidencia científica y planteamientos éticos. Se busca que se tengan en cuenta tanto el aspecto biológico de la sexualidad como la capacidad de hacerse persona en su núcleo sexual. De ahí que se analicen programas dirigidos a la educación sexual, basados tanto en la prevención sanitaria como en la antropología de la sexualidad, y apoyados por las instituciones familiares, que han demostrado una mejor acogida ante los riesgos de las enfermedades de transmisión sexual, y entre ellas la infección por el VPH.

Preventing cervical cancer and genital warts - How much protection is enough for HPV vaccines?

HPV associated disease is a global health problem: 5.2% of all cancers are HPV associated with HPV 16 and 18 accounting for 70% of cases of cervical cancer. Genital warts caused by HPV 6 and 11 have a lifetime risk of acquisition of 10%. HPV vaccines are subunit vaccines consisting of virus like particles comprised of the L1 major capsid protein. Two vaccines have been licenced since 2006/2007 and are in the National Immunisation programmes in 62 countries. Both vaccines include HPV 16 and 18 VLPs and one also includes HPV 6 and 11. The vaccines are highly immunogenic and well tolerated. Genital HPV is a sexually transmitted infection with peak incidence occurring just after the onset of sexual activity and the routine cohort for immunisation in almost all countries are adolescent girls 9-15 years of age with or without catch up for older adolescents and young women. Population effectiveness is now being demonstrated for these vaccines in countries with high vaccine coverage. HPV vaccines are highly immunogenic and effective and the original 3 dose schedules have already been reduced, for those 14 years and under, to 2 for both licenced vaccines. There is preliminary evidence that 1 dose of vaccine is as effective as 2 or 3 in preventing persistent HPV infection in the cervix in young women and further reductions in dosage may be possible if supported by appropriate virological, immunological and modelling studies.

Current status of human papillomavirus vaccination

PURPOSE OF REVIEW

In this article, we review the impact of the quadrivalent and bivalent prophylactic human papillomavirus (HPV) vaccines on HPV infection and disease, review alternative vaccine dosing schedules, the vaccination of men and the nine-valent HPV vaccine.

RECENT FINDINGS

HPV vaccines have had dramatic impacts on the prevalence of targeted HPV types (6,11,16 and 18), genital warts and precancerous cervical lesions. Population coverage would be facilitated by adopting two-dose schedules, with recent findings that two-dose schedules in young adolescents are as immunogenic as three doses in young adults. Extension of vaccination to men, particularly for men who have sex with men, could further reduce population prevalence of HPV and provide direct protection to men against genital warts and anal, penile and oropharyngeal cancers. The nine-valent HPV vaccine has demonstrated equivalent protection against the four types in the quadrivalent vaccine and high efficacy against the next five commonest causes of cervical cancer (HPV types 31,33,45,52 and 58). If cost-effective, it may extend the spectrum of protection against cervical cancer available through vaccination.

SUMMARY

HPV vaccination is an effective strategy for reducing the burden of HPV-related disease. New schedules, target populations and vaccines promise to expand this potential further.

HPV vaccines: how many doses are needed for protection?

HPV virus-like particle vaccines are highly immunogenic, well tolerated and are in the national immunization programs in more than 62 countries. Genital HPV is a sexually transmitted infection with first infection occurring just after the onset of sexual activity. The routine cohort for immunization in almost all countries are adolescent girls 9–15 years of age with or without catch-up for older adolescents and young women. In countries with vaccine coverage exceeding 50%, reductions in vaccine type HPV geno-prevalence and disease are being shown. The mechanism of protection is assumed to be via neutralizing antibody. Antibody concentration in adolescents less than 14 years of age after two doses of vaccine at 0 and 6 months are noninferior to women after three doses and in whom efficacy was demonstrated in randomized control trials. The original three-dose schedules have already been reduced in many countries, for those 14 years of age and under, to two doses at least 6 months apart for the licensed vaccines Cervarix® and GARDASIL®. There is preliminary evidence that one dose of vaccine is as effective as two or three doses at preventing persistent HPV infection in the cervix in young women and a one-dose schedule may be possible if supported by evidence from randomized controlled trials.

Surveillance of effects of HPV vaccination in Belgium

BACKGROUND

Early effects of HPV (human papillomavirus) vaccination are reflected by changes observable in young women attending cervical cancer screening.

SUBJECT AND METHODS

The SEHIB study included HPV geno-typing of ∼6000 continuous and 650 pathological cervical cell specimen as well as biopsies, collected from women in Belgium in 2010-2014. Data were linked to vaccination status.

RESULTS

HPV vaccination offered protection among women aged <30years against infection with HPV16 (vaccine effectiveness [VE]=67%, 95% CI: 48-79%), HPV18 (VE=93%, 95% CI: 52-99%), and high-risk HPV (VE=16%, 95% CI: 2-29%). Vaccination protected also against cytological lesions. Vaccination protected against histologically confirmed lesions: significantly lower absolute risks of CIN1+ (risk difference [RD]=-1.6%, 95% CI: -2.6% to -0.7%) and CIN3+ associated with HPV16/18 (RD=-0.3%, 95% CI -0.6% to -0.1%). Vaccine effectiveness decreased with age. Protection against HPV16 and 18 infection was significant in all age groups, however no protection was observed against cytological lesions associated with these types in age-group 25-29.

CONCLUSION

The SEHIB study demonstrates the effectiveness of HPV vaccination in Belgian young women in particular in age group 18-19. Declining effectiveness with increasing age may be explained by higher tendency of women already exposed to infection to get the vaccine.

Prophylactic HPV vaccination: past, present, and future

Human papillomavirus (HPV) is the necessary cause of cervical cancer, the fourth most common cancer and cause of cancer-related death in females worldwide. HPV also causes anal, vaginal, vulvar, penile, and oropharyngeal cancer. Prophylactic HPV vaccines based on recombinantly expressed virus-like particles have been developed. Two first-generation, U.S. Food and Drug Administration (FDA)-approved vaccines prevent infections and disease caused by HPV16 and HPV18, the two HPV genotypes that cause approximately 70% of cervical cancer, and one of these vaccines also prevents HPV6 and HPV11, the two HPV genotypes that cause 90% of genital warts. A next-generation vaccine, recently approved by the U.S. FDA, targets HPV16, HPV18, and five additional HPV genotypes that together causes approximately 90% of cervical cancer as well as HPV6 and HPV11. In clinical trials, these vaccines have shown high levels of efficacy against disease and infections caused by the targeted HPV genotypes in adolescent females and males and older females. Data indicate population effectiveness, and therefore cost effectiveness, is highest in HPV-naive young females prior to becoming sexually active. Countries that implemented HPV vaccination before 2010 have already experienced decreases in population prevalence of targeted HPV genotypes and related anogenital diseases in women and via herd protection in heterosexual men. Importantly, after more than 100 million doses given worldwide, HPV vaccination has demonstrated an excellent safety profile. With demonstrated efficacy, cost-effectiveness, and safety, universal HPV vaccination of all young, adolescent women, and with available resources at least high-risk groups of men, should be a global health priority. Failure to do so will result in millions of women dying from avertable cervical cancers, especially in low- and middle-income countries, and many thousands of women and men dying from other HPV-related cancers.

Long-Term Outcomes of Adding HPV Vaccine to the Anal Intraepithelial Neoplasia Treatment Regimen in HIV-Positive Men Who Have Sex With Men

BACKGROUND

Recent evidence shows that quadrivalent human papillomavirus (qHPV) vaccination in men who have sex with men (MSM) who have a history of high-grade anal intraepithelial neoplasia (HGAIN) was associated with a 50% reduction in the risk of recurrent HGAIN. We evaluated the long-term clinical and economic outcomes of adding the qHPV vaccine to the treatment regimen for HGAIN in human immunodeficiency virus (HIV)-positive MSM aged ≥27 years.

METHODS

We constructed a Markov model based on anal histology in HIV-positive MSM comparing qHPV vaccination with no vaccination after treatment for HGAIN, the current practice. The model parameters, including baseline prevalence, disease transitions, costs, and utilities, were either obtained from the literature or calibrated using a natural history model of anal carcinogenesis. The model outputs included lifetime costs, quality-adjusted life years, and lifetime risk of developing anal cancer. We estimated the incremental cost-effectiveness ratio of qHPV vaccination compared to no qHPV vaccination and decrease in lifetime risk of anal cancer. We also conducted deterministic and probabilistic sensitivity analyses to evaluate the robustness of the results.

RESULTS

Use of qHPV vaccination after treatment for HGAIN decreased the lifetime risk of anal cancer by 63% compared with no vaccination. The qHPV vaccination strategy was cost saving; it decreased lifetime costs by $419 and increased quality-adjusted life years by 0.16. Results were robust to the sensitivity analysis.

CONCLUSIONS

Vaccinating HIV-positive MSM aged ≥27 years with qHPV vaccine after treatment for HGAIN is a cost-saving strategy. Therefore, expansion of current vaccination guidelines to include this population should be a high priority.

From the monovalent to the nine-valent HPV vaccine

An investigational monovalent human papillomavirus (HPV) 16 virus-like particle vaccine has been shown to prevent persistent infection and cervical disease related to HPV 16 and was proof of concept (2002). Designed to prevent the bulk of invasive cervical cancer, quadrivalent (HPV 6/11/16/18) and bivalent (HPV 16/18) vaccines have been available since 2006 and 2007, respectively. They are highly effective in preventing HPV 16/18-related cervical precancer; the quadrivalent version also prevents genital warts related to HPV 6/11. It has been shown that the precursors of vulvar, vaginal and anal cancer related to the vaccine types are effectively prevented. This led to a paradigm shift from a female-only cervical cancer vaccine to a vaccine for the prevention of HPV-related disease and cancer for both sexes. Vaccination before the start of sexual activity is most effective, and consequently most programs target 9- to 12-year-olds. Additionally, recent studies have proven the noninferior immunoresponse of a two-dose schedule in these age cohorts. Gender-neutral vaccination has become more common; it improves coverage and also provides protection to all males. Recently a nine-valent HPV vaccine (HPV 6/11/16/18/31/33/45/52/58) was licensed; it provides high and consistent protection against infections and diseases related to these types, with ∼90% of cervical and other HPV-related cancers and precancers potentially being avoided. Coverage is key. Efforts must be made to provide HPV vaccination in low-resource countries that lack screening programs. In countries with cervical cancer screening, HPV vaccination will greatly affect screening algorithms.

High HIV, HPV, and STI prevalence among young Western Cape, South African women: EVRI HIV prevention preparedness trial

BACKGROUND

This study sought to assess the feasibility of conducting a phase III HIV prevention trial using a multivalent human papillomavirus (HPV) vaccine (Gardasil; Merck, Whitehouse Station, NJ).

METHODS

A total of 479 sexually active women aged 16-24 years in the Western Cape, South Africa, were enrolled in the Efficacy of HPV Vaccine to Reduce HIV Infection (EVRI) Trial. Of these, 402 were HIV negative, nonpregnant, and randomized 1:1 to receive Gardasil or a saline placebo vaccine. Vaccine doses were administered at enrollment, month 2, and month 6, and participants were followed for 1 month after the third dose. Enrollment HIV, HPV, other sexually transmitted infections (STIs), and cervical cytology were evaluated. Rates of accrual, vaccine compliance, and adherence to protocol were monitored.

RESULTS

High rates of accrual of eligible females to study (93%) and completion of the 3-dose vaccine series (91%) were noted, with few protocol violations. Ineligibility due to reported HIV positivity was 19%, and another 12% of those enrolled tested HIV positive. STI prevalence was high, with 6.2%, 10.9%, and 32.8% testing positive for syphilis, gonorrhea, and chlamydia, respectively. Cervical prevalence of ≥1 of 37 HPV types was 71%. STI and HPV prevalence was highest among the youngest women (<19 years).

CONCLUSIONS

Feasibility (successful accrual, retention, and vaccination) of conducting randomized placebo-controlled trials of HPV vaccines among HIV high-risk women in South Africa was demonstrated. This work demonstrates that phase III HIV prevention trials need to intervene at young ages and screen and treat multiple STIs concurrently to have a measurable impact on HIV acquisition.

Clinical effectiveness and cost-effectiveness of quadrivalent human papillomavirus vaccination in HIV-negative men who have sex with men to prevent recurrent high-grade anal intraepithelial neoplasia

We examined the long-term clinical and economic benefits of quadrivalent human papillomavirus (qHPV) vaccine as a secondary/adjunct prevention strategy in the prevention of recurrent high-grade intraepithelial neoplasia (HGAIN) in HIV-negative men who have sex with men (MSM) and are 27 years or older. We constructed a Markov model to evaluate the clinical effectiveness and cost-effectiveness of two strategies: (1) no qHPV vaccine after treatment for HGAIN versus (2) qHPV vaccine after treatment for HGAIN. Model parameters, including natural history of anal cancer, vaccine efficacy measured in terms of hazard ratio (HR) (decrease in the risk of recurrent HGAIN), HGAIN treatment efficacy, utilities, and costs, were obtained from the literature. The outcomes were measured in terms of lifetime risk of anal cancer, lifetime cost, quality-adjusted life years, and incremental cost-effectiveness ratios (ICERs). Sensitivity analysis was conducted on all model parameters. We found that vaccinating HIV-negative MSM reduced the lifetime risk of anal cancer by 60.77% at an ICER of US$87,240 per quality-adjusted life-year. The results were highly sensitive to vaccine efficacy, transition of HGAIN to anal cancer, cost of treatment for HGAIN, vaccine degree of protection over time, and the vaccine duration of protection and less sensitive to HPV clearance, cost of qHPV vaccine, and the transitions from normal to low-grade anal intraepithelial neoplasia (LGAIN) and normal to HGAIN. With an HR of 0.3, the ICER was well below a $50,000 willingness-to-pay threshold; with an HR of 0.5, the ICER was still below a threshold of $100,000. The most critical disease-related factor influencing the cost-effectiveness was the progression of HGAIN to anal cancer. At an annual transition probability below 0.001, the ICER was below $50,000. Vaccinating HIV-negative MSM treated for HGAIN decreases the lifetime risk of anal cancer and is likely to be a cost-effective intervention.

Long-term efficacy and safety of human papillomavirus vaccination

In this paper, we review the published evidence about the long-term efficacy of the available human papillomavirus (HPV) vaccines and their safety profile. Two prophylactic HPV vaccines - bivalent (bHPV) and quadrivalent (qHPV) - are now available, and vaccination programs are being widely implemented, primarily targeting adolescent girls. Efficacy has been widely demonstrated for both vaccines. Since the risk of HPV exposure potentially persists throughout a woman's sexual life, vaccine duration of protection is critical to overall effectiveness. Interpreting the results of long-term efficacy studies for the two HPV vaccines can be puzzling, due to the heterogeneity of studies, different methods used in the assessment of immunogenicity, histopathological and virological end points, and statistical power issues. Moreover, an immunologic correlate of protection has not yet been established, and it is unknown whether higher antibody levels will really result in a longer duration of protection. Disease prevention remains the most important measure of long-term duration of vaccine efficacy. To date, the longest follow-up of an HPV vaccine has been 9.4 years for the bHPV vaccine. Long-term follow-up for qHPV vaccine goes up to 8 years. The vaccine continues to be immunogenic and well tolerated up to 9 years following vaccination. All randomized controlled clinical trials of the bHPV and the qHPV vaccines provide evidence of an excellent safety profile. The most common complaint reported is pain in the injection site, which is self-limiting and spontaneously resolved. The incidence of systemic adverse events (AEs), serious AEs, and discontinuations due to a serious AE reported in clinical studies are similar between the two vaccines and their control groups. In particular, no increased risk of autoimmune disease has been shown among HPV-vaccinated subjects in long-term observation studies. As these are crucial topics in HPV vaccination, it is important to establish systems for continued monitoring of vaccine immunogenicity, efficacy, and safety over time.

Human papillomavirus vaccines: key factors in planning cost-effective vaccination programs

Prophylactic HPV vaccines hold tremendous potential for reducing cervical and non-cervical HPV-related disease burden worldwide. To maximize on this potential, policy officials will need to carefully consider available evidence, existing uncertainties and the cost-effectiveness of mass HPV vaccination programs in the context of their respective nations and/or regions. Proper harmonization of primary prevention strategies with secondary prevention efforts will also be important. Decisions following such considerations may ultimately depend on programmatic objectives, infrastructure and available resources. Continued research and surveillance surrounding HPV vaccination will be essential for filling current knowledge gaps, and forcing ongoing reconsiderations of selected immunization strategies.

HPV catch-up vaccination of young women: a systematic review and meta-analysis

BACKGROUND

While prophylactic human papilloma virus (HPV) vaccination is considered effective in young girls, it is unclear whether a catch-up vaccination of older girls would be beneficial. We, therefore, aimed to examine the potential health impact of a HPV catch-up vaccination of girls who were too old at the time of vaccine introduction, hence aged 16 and older.

METHODS

We systematically searched the literature for randomized clinical trials (RCTs) that examined the effect of HPV vaccines on overall mortality, cancer mortality and incidence, high-grade cervical intraepithelial neoplasia grade 2 and higher (CIN2+), vulvar intraepithelial neoplasia (VIN) and vaginal intraepithelial neoplasia (VaIN) grade 2 and higher lesions (VIN2+ and VaIN2+, respectively) genital warts (condyloma). We considered all lesions and those associated with HPV type(s) included in the vaccines. RCTs reporting on serious adverse events were also eligible. Selected publications were assessed for potential risk of bias, and we ascertained the overall quality of the evidence for each outcome using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Meta-analyses were performed, assuming both random and fixed effects, to estimate risk ratios (RR) and corresponding 95% confidence intervals (CI), using intention-to-treat and per-protocol populations.

RESULTS

We included 46 publications reporting on 13 RCTs. Most of the RCTs had a maximum follow-up period of four years. We identified no RCT reporting on the effect of HPV catch vaccination on overall and cancer related mortality, and on cervical cancer incidence. We found a borderline protective effect of a HPV catch-up vaccination on all CIN2+, with a pooled RR of 0.80 (95% CI: 0.62-1.02) for a follow-up period of 4 years. A HPV catch-up vaccination was associated with a reduction in VIN2+ and VaIN2+ lesions, and condyloma. No difference in risk of serious adverse events was seen in vaccinated participants versus unvaccinated women (pooled RR of 0.99 (0.91-1.08)).

CONCLUSIONS

This systematic review indicates that a HPV catch-up vaccination could be beneficial, however the long-term effect of such a vaccination, and its effect on cervical cancer incidence and mortality is still unclear.

Alternative dosage schedules with HPV virus-like particle vaccines

HPV vaccines can prevent multiple cancers in women and men. Difficulties in the cost and completion of the three-dose vaccine series have led to considerations of alternative dose schedules. In clinical trials, three doses given within a 12-month period versus the standard 6-month period yielded comparable results, and immunogenicity appears comparable with two doses in adolescent females compared to the three-dose series in adult females. While the data are generally supportive of moving to a two-dose vaccine schedule among young female adolescents, the adoption of a two-dose vaccine schedule still poses a potential risk to the strength and longevity of the immune response. Public health authorities implementing a two-dose vaccine schedule should devise risk management strategies to minimize the potential impact on cancer prevention.

Factors associated With Medicaid providers' recommendation of the HPV vaccine to low-income adolescent girls

PURPOSE

Human papillomavirus (HPV) vaccination in the United States remains a public health challenge with vaccine rates of 50%. Although health care providers can facilitate HPV vaccination, several factors may impede their ability to universally recommend the vaccine. To maximize the potential of HPV vaccines, it is important to understand challenges providers face in the clinical environment. The study sought to identify factors associated with recommendation of the HPV vaccine for low-income adolescents in the early (9-10), target (11-12), early adolescent catch-up (13-14), and late adolescent catch-up (15-17) vaccination groups.

METHODS

Surveys were mailed between October 2009 and April 2010 to a random sample of Florida-based physicians serving Medicaid-enrolled adolescents. Data were analyzed in 2013.

RESULTS

Among early adolescents, discomfort discussing sexually transmitted infections (STIs) with teens (odds ratio [OR] = 1.75), difficulty ensuring vaccine completion (OR = .73), and discomfort discussing STIs with parents (OR = .44) were associated with recommendation. For target adolescents, discomfort discussing STIs with teens (OR = 2.45), time constraints (OR = .70), vaccine efficacy concerns (OR = .65), discomfort discussing STIs with parents (OR = .33), obstetrics/gynecology (OR = .25) and family medicine (OR = .24) specialty, and non-Hispanic black patient (OR = .15) were associated with recommendation. In early catch-up adolescents, concerns that teens will practice riskier behaviors (OR = .57), discomfort discussing STIs with parents (OR = .47), and family medicine specialty (OR = .20) were associated with recommendation. For late catch-up adolescents, family medicine specialty (OR = .13) was associated with recommendation.

CONCLUSIONS

Modifiable factors that impede or influence provider recommendations of HPV vaccines can be addressed through intervention. Overall, findings suggest that efforts should focus on sexuality communication and family medicine specialty.

Immunological characterization of a modified vaccinia virus Ankara vector expressing the human papillomavirus 16 E1 protein

Women showing normal cytology but diagnosed with a persistent high-risk human papillomavirus (HR-HPV) infection have a higher risk of developing high-grade cervical intraepithelial neoplasia and cervical cancer than noninfected women. As no therapeutic management other than surveillance is offered to these women, there is a major challenge to develop novel targeted therapies dedicated to the treatment of these patients. As such, E1 and E2 antigens, expressed early in the HPV life cycle, represent very interesting candidates. Both proteins are necessary for maintaining coordinated viral replication and gene synthesis during the differentiation process of the epithelium and are essential for the virus to complete its normal and propagative replication cycle. In the present study, we evaluated a new active targeted immunotherapeutic, a modified vaccinia virus Ankara (MVA) vector containing the E1 sequence of HPV16, aimed at inducing cellular immune responses with the potential to help and clear persistent HPV16-related infection. We carried out an extensive comparative time course analysis of the cellular immune responses induced by different schedules of immunization in C57BL/6 mice. We showed that multiple injections of MVA-E1 allowed sustained HPV16 E1-specific cellular immune responses in vaccinated mice and had no impact on the exhaustion phenotype of the generated HPV16 E1-specific CD8⁺ T cells, but they led to the differentiation of multifunctional effector T cells with high cytotoxic capacity. This study provides proof of concept that an MVA expressing HPV16 E1 can induce robust and long-lasting E1-specific responses and warrants further development of this candidate.

Primary prophylactic human papillomavirus vaccination programs: future perspective on global impact

Of the 40 types of human papillomavirus that can infect the mucosal epithelium, four types can now be prevented using prophylactic vaccination. Two of these types (high-risk types 16 and 18) cause 70% of cervical cancers, a proportion of other genital cancers and a subset of head and neck cancers. The low-risk types 6 and 11 cause 90% of genital warts and the disease recurrent respiratory papillomatosis. Thus, if primary HPV vaccination programs can be implemented effectively, the potential for a reduction in global disease burden is great. This article considers the current issues and challenges in delivering primary HPV vaccination programs effectively and the likely impact of the vaccines in both the near and more distant future.

HPV vaccine cross-protection: Highlights on additional clinical benefit

Prophylactic human papillomavirus (HPV) vaccines are administered in vaccination programs, targeted at young adolescent girls before sexual exposure, and in catch-up programs for young women in some countries. All the data indicate that HPV-virus-like particles (VLPs) effectively prevent papillomavirus infections with a high level of antibodies and safety. Since non-vaccine HPV types are responsible for about 30% of cervical cancers, cross-protection would potentially enhance primary cervical cancer prevention efforts. High levels of specific neutralizing antibodies can be generated after immunization with HPV VLPs. Immunity to HPV is type-specific. However, if we consider the phylogenetic tree including the different HPV types, we realize that a certain degree of cross-protection is possible, due to the high homology of some viral types with vaccine ones. The assessment of cross-protective properties of HPV vaccines is an extremely important matter, which has also increased public health implications and could add further value to their preventive potential. The impact of cross-protection is mostly represented by a reduction of cervical intraepithelial neoplasia CIN2-3 more than what expected. In this article we review the mechanisms and the effectiveness of Bivalent (HPV-16/-18) and Quadrivalent (HPV-6/-11/-16/-18) HPV vaccine cross-protection, focusing on the critical aspects and the potential biases in clinical trials, in order to understand how cross-protection could impact on clinical outcomes and on the new perspectives in post-vaccine era.

Age-specific occurrence of HPV16- and HPV18-related cervical cancer

The age-specific occurrence of cervical cancer related to human papillomavirus (HPV) genotypes HPV16 and HPV18, the two targeted by current HPV vaccines, is not well described. We therefore used data from two large, tissue-based HPV genotyping studies of cervical cancer, one conducted in New Mexico (n = 744) and an International study restricted to cancers (n = 1,729) from Europe, North America, and Australia to represent those regions with widely available cervical cancer screening facilities. HPV results were categorized as HPV16- or HPV18-positive (HPV16/18) versus other HPV genotype. We observed a decreasing proportion of HPV16/18-positive cancers with increasing age in the International study (Ptrend < 0.001) and New Mexico study (Ptrend < 0.001). There was no heterogeneity in the relationship between age of diagnosis and the proportion of HPV16/18-positive cancers between studies (P = 0.8). Combining results from the two studies (n = 2,473), the percentages of HPV16/18-positive cases were 77.0% [95% confidence interval (CI): 75.1%-78.9%] for women less than 65 years old and 62.7% [95% confidence interval (CI): 58.4%-66.9%] for women aged 65 and older (P < 0.001). In women who are under the age of 25 and have been vaccinated before becoming sexually active, the cervical cancer incidence is expected to be approximately 3.5 per million by 2020. HPV vaccination against HPV16/18 may have a greater impact on cervical cancers in women under 65 than in women aged 65 and older. These data will inform the age-specific impact of HPV vaccination and its integration with cervical cancer screening activities.

Human papillomavirus vaccine in adolescent women: a 2012 update

PURPOSE OF REVIEW

Despite recommendations from the Advisory Committee on Immunization Practices (ACIP) for routine vaccination of adolescents with the human papillomavirus (HPV) vaccine, U.S. coverage among women remains less than 50%, with that of adolescent men below 2%.

RECENT FINDINGS

Ongoing studies document the efficacy and safety of the HPV vaccine. Nevertheless, misconceptions and negative attitudes persist and serve as barriers to vaccine uptake. Additionally, other factors such as age, insurance status, poverty status, and racial or ethnic background have been associated with diminished vaccine uptake and poor completion rates. Internationally, HPV vaccination programs and school-based programs have achieved increased rates of uptake and series completion. HPV vaccination coverage may also be facilitated by improving communication between physicians, parents, and adolescents as well as by addressing common misconceptions about the vaccine.

SUMMARY

This review highlights significant findings of recent literature on HPV vaccination of adolescent women with a special focus on uptake, series completion, communication, disparities in vaccine coverage, and other health outcomes associated with HPV vaccination.

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.

Effect of the human papillomavirus (HPV) quadrivalent vaccine in a subgroup of women with cervical and vulvar disease: retrospective pooled analysis of trial data

OBJECTIVES

To determine the effect of human papillomavirus (HPV) quadrivalent vaccine on the risk of developing subsequent disease after an excisional procedure for cervical intraepithelial neoplasia or diagnosis of genital warts, vulvar intraepithelial neoplasia, or vaginal intraepithelial neoplasia.

DESIGN

Retrospective analysis of data from two international, double blind, placebo controlled, randomised efficacy trials of quadrivalent HPV vaccine (protocol 013 (FUTURE I) and protocol 015 (FUTURE II)).

SETTING

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

PARTICIPANTS

Among 17,622 women aged 15-26 years who underwent 1:1 randomisation to vaccine or placebo, 2054 received cervical surgery or were diagnosed with genital warts, vulvar intraepithelial neoplasia, or vaginal intraepithelial neoplasia.

INTERVENTION

Three doses of quadrivalent HPV vaccine or placebo at day 1, month 2, and month 6.

MAIN OUTCOME MEASURES

Incidence of HPV related disease from 60 days after treatment or diagnosis, expressed as the number of women with an end point per 100 person years at risk.

RESULTS

A total of 587 vaccine and 763 placebo recipients underwent cervical surgery. The incidence of any subsequent HPV related disease was 6.6 and 12.2 in vaccine and placebo recipients respectively (46.2% reduction (95% confidence interval 22.5% to 63.2%) with vaccination). Vaccination was associated with a significant reduction in risk of any subsequent high grade disease of the cervix by 64.9% (20.1% to 86.3%). A total of 229 vaccine recipients and 475 placebo recipients were diagnosed with genital warts, vulvar intraepithelial neoplasia, or vaginal intraepithelial neoplasia, and the incidence of any subsequent HPV related disease was 20.1 and 31.0 in vaccine and placebo recipients respectively (35.2% reduction (13.8% to 51.8%)).

CONCLUSIONS

Previous vaccination with quadrivalent HPV vaccine among women who had surgical treatment for HPV related disease significantly reduced the incidence of subsequent HPV related disease, including high grade disease.

TRIAL REGISTRATIONS

NCT00092521 and NCT00092534.

Prevention of recurrent high-grade anal neoplasia with quadrivalent human papillomavirus vaccination of men who have sex with men: a nonconcurrent cohort study

BACKGROUND

Most squamous cell anal cancers and precancerous lesions are attributed to human papillomavirus (HPV) infection. By preventing HPV infection, quadrivalent HPV vaccine (qHPV) reduces risk of anal cancer/precancerous lesions in young men who have sex with men (MSM) without history of anal cancer/precancerous lesions. In our practice, many persons with history of precancerous anal lesions or high-grade anal intraepithelial neoplasia (HGAIN) have been vaccinated electively. We determined whether qHPV is effective at preventing recurrence of HGAIN.

METHODS

This nonconcurrent cohort study evaluated 202 patients with a history of previously treated HGAIN. Eighty-eight patients were vaccinated, and 114 patients were unvaccinated. We determined the recurrence rate of histologic HGAIN in vaccinated versus unvaccinated patients.

RESULTS

During 340.4 person-years follow-up, 12 (13.6%) vaccinated patients and 35 (30.7%) unvaccinated patients developed recurrent HGAIN. Multivariable hazards ratio (HR) analysis showed testing positive for oncogenic HPV genotypes within 8 months before study entry was associated with increased risk of recurrent HGAIN at 2 years after study entry (HR 4.06; 95% confidence interval [CI], 1.58-10.40; P = .004), and qHPV was associated with decreased risk of recurrent HGAIN (HR .50; 95% CI, .26-.98; P = .04). Among patients infected with oncogenic HPV, qHPV was associated with decreased risk of recurrent HGAIN at 2 years after study entry (HR .47; 95% CI, .22-1.00; P = .05).

CONCLUSIONS

qHPV significantly reduces HGAIN recurrence among MSM and may be an effective posttreatment adjuvant form of therapy. A randomized controlled trial is needed to confirm these results.

Evidence of immune memory 8.5 years following administration of a prophylactic human papillomavirus type 16 vaccine

BACKGROUND

The duration of protection conferred by prophylactic human papillomavirus (HPV) L1 virus-like particle vaccines is a critical determinant of their public health impact. A feature of vaccines that confer long-term immunity is their ability to induce immune memory.

OBJECTIVES

We evaluated antibody responses against HPV types 6, 11, 16 and 18 following administration of the quadrivalent HPV-6/11/16/18 vaccine to women who had previously received a monovalent HPV-16 vaccine.

STUDY DESIGN

As part of an extended follow-up study conducted between 2006 and 2009 in Seattle, Washington, we administered the quadrivalent HPV-6/11/16/18 vaccine to 52 women (19 vaccine and 33 placebo recipients) who had participated in a monovalent HPV-16 vaccine trial 8.5 years earlier. Serum samples were tested for anti-HPV antibodies using competitive Luminex immunoassay.

RESULTS

Following administration of the first dose of the quadrivalent HPV-6/11/16/18 vaccine, the anti-HPV-16 geometric mean titer among monovalent HPV-16 vaccine recipients (GMT=5024.0 milli-Merck units per milliliter [mMU/mL]; 95% confidence interval [CI]: 2710.1, 9313.6 mMU/mL) substantially exceeded that among the placebo recipients (GMT=136.1; 95% CI: 78.5, 235.8 mMU/mL; p<0.01) and their own highest anti-HPV-16 response observed during the original trial (GMT at month 7 of the original trial=1552.7 mMU/mL; 95% CI: 1072.6, 2247.7 mMU/mL; p<0.01).

CONCLUSIONS

The findings suggest that the administration of the three-dose regimen of the monovalent HPV-16 vaccine had produced memory lymphocytes, characterized by a heightened immune response following administration of the quadrivalent HPV-6/11/16/18 vaccine that effectively served as an antigen challenge.

Comparative immunogenicity and safety of human papillomavirus (HPV)-16/18 vaccine and HPV-6/11/16/18 vaccine: follow-up from months 12-24 in a Phase III randomized study of healthy women aged 18-45 years

In this observer-blind study (NCT00423046), women (N=1,106), stratified by age (18-26, 27-35, 36-45 y), were randomized (1:1) to receive the HPV-16/18 vaccine (Cervarix®, GlaxoSmithKline Biologicals, Months 0, 1, 6) or the HPV-6/11/16/18 vaccine (Gardasil® Merck & Co., Inc., Months 0, 2, 6). Month 7 results were previously reported; we now report Month 24 results. In the according-to-protocol cohort for immunogenicity (seronegative and DNA-negative at baseline for HPV type analyzed), seropositivity rates of neutralizing antibodies (nAbs) [pseudovirion-based neutralization assay] were, across all age strata, 100% (HPV-16/18 vaccine) and 97.5-100% (HPV-6/11/16/18 vaccine) for HPV-16, and 99.0-100% (HPV-16/18 vaccine) and 72.3-84.4% (HPV-6/11/16/18 vaccine) for HPV-18. Corresponding geometric mean titers (GMTs) were 2.4-5.8-fold higher for HPV-16 and 7.7-9.4-fold higher for HPV-18 with the HPV-16/18 vaccine versus the HPV-6/11/16/18 vaccine; HPV-16 and HPV-18 GMTs were significantly higher with the HPV-16/18 vaccine than the HPV-6/11/16/18 vaccine (p< 0.0001) in the total vaccinated cohort (received ≥1 vaccine dose, irrespective of baseline sero/DNA-status). Similar results were obtained using enzyme-linked immunosorbent assay (ELISA). Positivity rates and GMTs of antigen-specific IgG antibodies in cervicovaginal secretions (ELISA) were not significantly different between vaccines. At Month 24, CD4⁺ T-cell responses for HPV-16 and HPV-18 were higher with the HPV-16/18 vaccine; memory B-cell response was higher for HPV-18 with the HPV-16/18 vaccine and similar between vaccines for HPV-16. Both vaccines were generally well tolerated. Although an immunological correlate of protection has not been defined, differences in the magnitude of immune response between vaccines may represent determinants of duration of protection.

New Approaches to Immunotherapy for HPV Associated Cancers

Cervical cancer is the second most common cancer of women worldwide and is the first cancer shown to be entirely induced by a virus, the human papillomavirus (HPV, major oncogenic genotypes HPV-16 and -18). Two recently developed prophylactic cervical cancer vaccines, using virus-like particles (VLP) technology, have the potential to prevent a large proportion of cervical cancer associated with HPV infection and to ensure long-term protection. However, prophylactic HPV vaccines do not have therapeutic effects against pre-existing HPV infections and do not prevent their progression to HPV-associated malignancy. In animal models, therapeutic vaccines for persisting HPV infection can eliminate transplantable tumors expressing HPV antigens, but are of limited efficacy in inducing rejection of skin grafts expressing the same antigens. In humans, clinical trials have reported successful immunotherapy of HPV lesions, providing hope and further interest. This review discusses possible new approaches to immunotherapy for HPV associated cancer, based on recent advances in our knowledge of the immunobiology of HPV infection, of epithelial immunology and of immunoregulation, with a brief overview on previous and current HPV vaccine clinical trials.

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.

Asia oceania guidelines for the implementation of programs for cervical cancer prevention and control

This paper aims to provide evidence-based recommendations for health professionals, to develop a comprehensive cervical cancer program for a clinic, a community, or a country. Ensuring access to healthcare is the responsibility of all societies, and the Asia Oceania Research Organisation in Genital Infections and Neoplasia (AOGIN) is committed to working collaboratively with governments and health professionals to facilitate prevention programs, to protect girls and women from cervical cancer, a disease that globally affects 500,000 and kills nearly 300,000 women annually, just over half of whom are in the Asia Oceania region. We share the vision that a comprehensive program of vaccination, screening, and treatment should be made accessible to all girls and women in the world. The primary purpose of these guidelines is to provide information on scientific evidence on the different modalities and approaches of cervical cancer prevention programs, for high resource and low resource settings. The secondary purpose is to provide an overview of the current situation of cervical cancer control and prevention in various Asian Oceania countries: their views of an ideal program, identified obstacles, and suggestions to overcome them are discussed.

Quadrivalent human papillomavirus (types 6, 11, 16, 18) recombinant vaccine (Gardasil®): a review of its use in the prevention of premalignant genital lesions, genital cancer and genital warts in women

Quadrivalent human papilloma virus (HPV) [types 6, 11, 16, 18] recombinant vaccine (Gardasil®; Silgard®) is composed of virus-like particles (VLPs) formed by self-assembly of recombinant L1 capsid protein from each of HPV types 6, 11, 16 and 18. The VLPs are noninfectious, containing no DNA, and are highly immunogenic, inducing high levels of neutralizing antibodies against the particular HPV types when administered to animals or humans. Quadrivalent HPV vaccine is indicated for use from the age of 9 years for the prevention of premalignant genital lesions (cervical, vulvar and vaginal), cervical cancer and external genital warts (condyloma acuminata) causally related to certain oncogenic or specific HPV types. In placebo-controlled clinical trials, quadrivalent HPV vaccine administered as three doses over 6 months provided high-level protection against infection or disease caused by the vaccine HPV types over 2-4 years of follow-up in females aged 15-45 years who were naive to the vaccine HPV types. A degree of cross-protection against certain other non-vaccine high-risk HPV types was also observed. The vaccine is not effective against current infection with a vaccine HPV type. Girls or women with current infection with one or more of the vaccine HPV types gained protection from infection or disease caused by the remaining vaccine HPV types and they were also protected against reinfection with the same HPV type after clearance of an infection caused by a vaccine HPV type. High seroconversion rates and high levels of anti-HPV antibodies were observed in all vaccinated individuals of all age ranges from 9 to 45 years. No correlation was found between antibody levels and protective efficacy of the vaccine. Rechallenge with quadrivalent HPV vaccine produced a potent anamnestic humoral immune response. The vaccine is generally well tolerated and is projected to be cost effective in most pharmacoeconomic models. Therefore, quadrivalent HPV vaccine offers an effective means, in combination with screening programmes, to substantially reduce the burden of HPV-related precancerous lesions and cancer, particularly cervical cancer, as well as anogenital warts.

Efficacy and safety of prophylactic vaccines against cervical HPV infection and diseases among women: a systematic review & meta-analysis

Background

We conducted a systematic review and meta-analysis to assess efficacy and safety of prophylactic HPV vaccines against cervical cancer precursor events in women.

Methods

Randomized-controlled trials of HPV vaccines were identified from MEDLINE, Cochrane Central Register of Controlled Trials, conference abstracts and references of identified studies, and assessed by two independent reviewers. Efficacy data were synthesized using fixed-effect models, and evaluated for heterogeneity using I² statistic.

Results

Seven unique trials enrolling 44,142 females were included. The fixed-effect Relative Risk (RR) and 95% confidence intervals were 0.04 (0.01-0.11) and 0.10 (0.03-0.38) for HPV-16 and HPV 18-related CIN2+ in the per-protocol populations (PPP). The corresponding RR was 0.47 (0.36-0.61) and 0.16 (0.08-0.34) in the intention-to-treat populations (ITT). Efficacy against CIN1+ was similar in scale in favor of vaccine. Overall vaccines were highly efficacious against 6-month persistent infection with HPV 16 and 18, both in the PPP cohort (RR: 0.06 [0.04-0.09] and 0.05 [0.03-0.09], respectively), and the ITT cohorts (RR: 0.15 [0.10-0.23] and 0.24 [0.14-0.42], respectively). There was limited prophylactic effect against CIN2+ and 6-month persistent infections associated with non-vaccine oncogenic HPV types. The risk of serious adverse events (RR: 1.00, 0.91-1.09) or vaccine-related serious adverse events (RR: 1.82; 0.79-4.20) did not differ significantly between vaccine and control groups. Data on abnormal pregnancy outcomes were underreported.

Conclusions

Prophylactic HPV vaccines are safe, well tolerated, and highly efficacious in preventing persistent infections and cervical diseases associated with vaccine-HPV types among young females. However, long-term efficacy and safety needs to be addressed in future trials.

Unresolved questions concerning human papillomavirus infection and transmission: a modelling perspective

Mathematical transmission models are widely used to forecast the potential impact of interventions such as vaccination and to inform the development of health policy. Effective vaccines are now available for the prevention of cervical cancer and other diseases attributable to human papillomavirus (HPV). Considerable uncertainties remain regarding the characterisation of HPV infection and its sequelae, infectivity, and both vaccine-conferred and naturally-acquired immunity. In this review, we discuss the key knowledge gaps that impact on our ability to develop accurate models of HPV transmission and vaccination.

HPV - immune response to infection and vaccination

HPV infection in the genital tract is common in young sexually active individuals, the majority of whom clear the infection without overt clinical disease. However most of those who develop benign lesions eventually mount an effective cell mediated immune (CMI) response and the lesions regress.

Failure to develop effective CMI to clear or control infection results in persistent infection and, in the case of the oncogenic HPVs, an increased probability of progression to CIN3 and invasive carcinoma. The prolonged duration of infection associated with HPV seems to be associated with effective evasion of innate immunity thus delaying the activation of adaptive immunity.

Natural infections in animals show that neutralising antibody to the virus coat protein L1 is protective suggesting that this would be an effective prophylactic vaccine strategy. The current prophylactic HPV VLP vaccines are delivered i.m. circumventing the intra-epithelial immune evasion strategies. These vaccines generate high levels of antibody and both serological and B cell memory as evidenced by persistence of antibody and robust recall responses. However there is no immune correlate - no antibody level that correlates with protection. Recent data on how HPV infects basal epithelial cells and how antibody can prevent this provides a mechanistic explanation for the effectiveness of HPV VLP vaccines.

Human papillomavirus vaccines: current status and future prospects

Worldwide, cervical cancer is the second most common cancer of women. Less-developed countries bear the greatest burden in terms of morbidity and mortality, largely due to the lack of organized screening programmes. Cervical cancer is the first cancer shown to be caused solely by virological agents: oncogenic genotypes of human papillomavirus (HPV). Two recently developed prophylactic cervical cancer vaccines, which are based on viral-like particle (VLP) technology of HPV, have the capacity to diminish a large proportion of cervical cancer cases worldwide. However, to be successful public health tools, they need to be widely implemented to the appropriate target population, preferably prior to first sexual intercourse. To increase vaccination coverage, national programmes in some countries have also included catch-up vaccination, for a limited time period, to young adult women aged up to 26 years. Despite the excellent efficacy for high-grade dysplasia due to vaccine-related HPV types (near to 100%) and immunogenicity induced against the HPV types 16 and 18 in females naive to those HPV types pre-vaccination, some form of cervical precancer screening will still be necessary. Immunity to HPV is primarily type specific, and thus protection induced by the current generation of vaccines, based on a limited number of HPV VLP types, cannot provide complete protection against all oncogenic HPV types. Both these vaccines translate to protection of cervical cancer in the order of 70-75%, which represents the percentage of invasive cancers attributable to HPV-16 and -18. Challenges to ensuring the successful control of this largely preventable disease include endorsement by governments and policy makers, affordable prices, education at all levels, overcoming barriers to vaccination and continued adherence to screening programmes.

Understanding differences in predictions of HPV vaccine effectiveness: A comparative model-based analysis

Mathematical models of HPV vaccine effectiveness and cost-effectiveness have produced conflicting results. The aim of this study was to use mathematical models to compare and isolate the impact of the assumptions most commonly made when modeling the effectiveness of HPV vaccines. Our results clearly show that differences in how we model natural immunity, herd immunity, partnership duration, HPV types, and waning of vaccine protection lead to important differences in the predicted effectiveness of HPV vaccines. These results are important and useful to assist modelers/health economists in choosing the appropriate level of complexity to include in their models, provide epidemiologists with insight on key data necessary to increase the robustness of model predictions, and help decision makers better understand the reasons underlying conflicting results from HPV models.

Safety, tolerability, and immunogenicity of gardasil given concomitantly with Menactra and Adacel

OBJECTIVES

Multinational phase III trials of a human papillomavirus vaccine, Gardasil, have shown the vaccine to be generally well-tolerated, efficacious, and immunogenic. We evaluated the immunogenicity and safety of Gardasil administered concomitantly with Menactra and Adacel.

METHODS

In this open-label study, boys (n = 394) and girls (n = 648) aged 10 to 17 were randomly assigned in a 1:1 ratio as follows: group A (concomitant administration) received a 0.5-mL dose of Gardasil at day 1, month 2, and month 6 and a 0.5-mL dose of Menactra and Adacel on day 1; group B (nonconcomitant administration) received Gardasil at day 1, month 2, and month 6 and Menactra and Adacel at month 1. Antibody levels for all vaccine components were measured. Systemic, injection-site, and serious adverse experiences (AEs) were monitored.

RESULTS

Immune responses after concomitant administration of the 3 vaccines were noninferior to nonconcomitant administration. Seroconversion for Gardasil was > or = 99% in both groups A and B. For Menactra and Adacel, concomitant administration of the vaccines was demonstrated to be noninferior to nonconcomitant administration. Concomitant administration was generally well-tolerated. No participants withdrew because of an AE. One serious AE of transient muscular weakness of <24 hours' duration after the third Gardasil injection was reported in group B and was deemed possibly vaccine-related by the investigator.

CONCLUSIONS

Overall, concomitant administration was generally well-tolerated and did not interfere with the immune response to the respective vaccines. Concomitant administration should minimize the number of visits required to deliver each vaccine individually, leading to increased compliance and more effective disease prevention.