Cost–consequences evaluation between bivalent and quadrivalent HPV vaccines in Italy: The potential impact of different cross-protection profiles

An Updated Analysis of the Impact of HPV Vaccination Based on Long-term Effectiveness in the Netherlands

INTRODUCTION

Vaccination against human papillomavirus (HPV) is considered the most effective strategy to protect women from cervical cancer. Three HPV vaccines are currently licensed in Europe and, although they are generally supported by favorable health economic outcomes, current models fall short in predicting vaccination benefits. Here, we aim to re-evaluate the health benefits of HPV vaccination, using updated long-term effectiveness data and emphasizing quality of life losses related to pre-cancer disease and treatment.

METHODS

We used a static Markov model that compared "only screening" (includes unvaccinated girls) and "vaccination" (assumes 100% vaccination coverage with the bivalent HPV vaccine). A lifetime cohort of 100,000 uninfected 12-year-old girls was included, in which the number of cases with cervical intraepithelial neoplasia grade 2 or higher/3 (CIN2+, CIN3), cervical cancer, and cervical cancer deaths per scenario were determined. Furthermore, the reduction in major excisional procedures, the preterm deliveries averted, and the related gain in quality-adjusted life years (QALYs) due to vaccination were estimated.

RESULTS

The bivalent vaccine showed larger reductions in CIN2+, CIN3, cervical cancer cases, cervical cancer deaths, and major excisional treatments, after including long-term efficacy and effectiveness data, compared to previous data. Moreover, we observed an increased amount of QALYs gained due to prevention of major excisional treatment and the negative side effects related to it.

CONCLUSIONS

Updated health economic models for HPV vaccination, using updated and long-term effectiveness data and including prevention of treatment-related side effects, demonstrate a substantial additional positive effect on vaccination outcomes. Indeed, extrapolation of the bivalent HPV vaccine's updated long-term effectiveness data against HPV-related cervical diseases shows that the positive effects of vaccination may be more substantial than previously estimated. There is a graphical abstract available for this article.

Comparative Cost-Effectiveness Analysis of Two Different Two-Dose Human Papillomavirus Vaccines in Malaysia

Purpose:

To comparatively evaluate the results of a 2-dose human papillomavirus (HPV) vaccination programme with the AS04-adjuvanted HPV16/18 vaccine (AS04-HPV-16/18v) or HPV-6/11/16/18 vaccine (4vHPVv), in addition to cervical cancer (CC) screening, in Malaysia.

Methods:

A lifetime Markov model replicating the natural history of HPV in 13-year-old girls was adapted to Malaysia to assess the impact of vaccination on pre-cancerous lesions, genital warts and CC cases, CC deaths, quality-adjusted life years (QALYs), and costs from the perspective of the Malaysian Ministry of Health. Vaccine effectiveness was based on efficacy and HPV type distribution. Both vaccines were assumed to have equal efficacy against vaccine-type HPV but differed for protection against non-vaccine types. Vaccine price parity was used and health and cost outcomes were discounted at 3%/annum. Sensitivity analyses tested the robustness of the results.

Results:

The model predicted that AS04-HPV-16/18v would result in 361 fewer CC cases and 115 fewer CC deaths than 4vHPVv, whereas 4vHPVv averted 4,241 cases of genital warts over the cohort’s lifetime. Discounted total costs showed savings of 18.50 million Malaysian Ringgits and 246 QALYs in favour of AS04-HPV-16/18v. In one-way sensitivity analyses, the discount rate was the most influential variable for costs and QALYs, but AS04-HPV-16/18v remained dominant throughout. A two-way sensitivity analysis to assess the longevity of cross-protection for both vaccines confirmed the base-case.

Conclusions:

In Malaysia, the use of AS04-HPV-16/18v, in addition to screening, was modelled to be dominant over 4vHPVv, with greater estimated CC benefits and lower costs.

The health-economic studies of HPV vaccination in Southeast Asian countries: a systematic review

INTRODUCTION

The cervical cancer-related burden is an important problem in Southeast Asian (SEA) countries. However, only 3 out of 11 countries implement the comprehensive prevention program. Areas covered: This is a retrospective review from all relevant studies until 2015 from two main databases, MEDLINE/Pubmed and Embase in order to provide an evidence on the health economics of HPV vaccination in the region. Expert commentary: The implementation of HPV vaccination will generate substantial health and economic benefit in SEA countries since the number of cervical cancer cases in this region are generally high. Therefore, a clear recommendation on how HPV vaccination should be implemented in a country, for example on how many doses will be used, how much cost is required or is it a school based- or clinical based-delivery, is critically required.

The cost-effectiveness of HPV vaccination in addition to screening: a Dutch perspective

Addition of the HPV vaccine to available cytological screening has been proposed to increase HPV-related cancer prevention. A comprehensive review on this combined strategy implemented in the Netherlands is lacking. For this review, we therefore analyzed all relevant studies on cost-effectiveness of HPV vaccines in combination with cervical screening in the Netherlands. Most of the studies agree that vaccination in pre-sexual-activity periods of life is cost-effective. Based on published sensitivity analyses, the incremental cost-effectiveness ratio was found to be mainly driven by vaccine cost and discount rates. Fewer vaccine doses, inclusion of additional benefits of these vaccines to prevent HPV-related non-cervical cancers and vaccination of males to further reduce the burden of HPV-induced cancers are three relevant options suggested to be investigated in upcoming economic evaluations.

The impact of HPV female immunization in Italy: model based predictions

The Human Papillomavirus (HPV) is a sexually transmitted virus that causes cervical cancer. Since 2008 a vaccination program targeting 12-year-old girls has been initiated in Italy, backing up the cervical screening program already active since 1996. We propose a mathematical model of HPV transmission dynamics with the aim of evaluating the impact of these prevention strategies. The model considers heterosexual transmission of HPV types 16 and 18, structured by sex, age and sexual activity level, where transition to sexual activity is explicitly modeled from recent survey data. The epidemiological structure is a hybrid SIS/SIR, where a fraction of individuals recovering from infection develops permanent immunity against reinfection. Infections may progress to cervical lesions and cancer and heal spontaneously or upon treatment. Women undergoing hysterectomy (either after treatment of HPV lesions or by other causes) also transmit HPV infection. The model fits well both the age-specific prevalence of HPV infections and the incidence of cervical cancers in Italy, and accurately reproduces the decreasing trend in cancer incidence due to the introduction of the screening program. The model predicts that if the screening coverage is maintained at current levels, even in the absence of vaccination, such trend will continue in the next few decades, eventually plateauing at 25% below the current level. The additional initiation of routine vaccination targeting 12-year-old girls will further reduce cervical cancer incidence by two thirds at equilibrium, under realistic assumptions of 70% coverage and a duration of protective immunity of 50 years. If catch-up immunization of 25-year-old women at first cervical screening is also introduced, about 3,000 cervical cancer cases overall can be averted, corresponding to 9.6% of all cases expected in the scenario without catch-up. We conclude that HPV vaccination in addition to cervical screening will significantly reduce the burden of cervical cancer in Italy.

Estimation of the potential overall impact of human papillomavirus vaccination on cervical cancer cases and deaths

BACKGROUND

Human papillomavirus (HPV) vaccination offers potential for primary prevention of HPV-related pre-cancers and cancers as demonstrated in clinical trials. Mathematical models have estimated the potential real-life impact of vaccination on the burden of cervical cancer (CC). However, these are restricted to evaluations in a limited number of countries.

METHODS

Potential decline in CC cases and deaths with the AS04-adjuvanted HPV-16/18 vaccine of young girls naïve to HPV, was estimated at steady-state (vaccine coverage: 0-100%) based on clinical trial and country-specific incidence data. Data on vaccine efficacy were taken from the end of study PATRICIA trial of the AS04-adjuvanted HPV-16/18 vaccine. The numbers of cases and deaths due to HPV-16/18 were estimated and compared with those due to any HPV type to estimate the additional cases prevented. This difference estimates CC cases and deaths avoided due to protection against non-vaccine HPV types. Cost-offsets due to reductions in CC treatment were estimated for five countries (Brazil, Canada, Italy, Malaysia and South African Republic) using country-specific unit cost data. Additionally, cervical intraepithelial neoplasia grade 2 or 3 (CIN2/3)-related burden (cases and treatment costs) prevented by vaccination were estimated for two countries (Italy and Malaysia).

RESULTS

HPV vaccination could prevent a substantial number of CC cases and deaths in countries worldwide, with associated cost-offsets due to reduced CC treatment. Cross-protection increased the estimated potential number of CC cases and deaths prevented by 34 and 18% in Africa and Oceania, respectively. Moreover, vaccination could result in a substantial reduction in the number of CIN2/3 lesions and associated costs.

CONCLUSION

HPV vaccination could reduce the burden of CC and precancerous lesions in countries worldwide, part of disease burden reduction being related to protection against non HPV-16/18 related types.

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.

HPV vaccination and cervical cancer

Cervical cancer is the third most common cancer in women worldwide and often affects women under 40 years with young families. Vaccination against the human papillomavirus (HPV) is a major advance, since it offers primary prevention against the infectious agent that is the main cause of the disease. Two prophylactic vaccines have shown great promise in clinical trials. One of these (Gardasil(®)) contains all four HPV types, offering protection against genital warts (types 6 and 11) as well as cervical cancer (types 16 and 18). The other (Cervarix(®)) contains types 16 and 18, targeting cervical cancer alone, but also has a degree of cross-protection against types 31 and 45, which could significantly increase the level of protection. Adolescent girls remain the primary target of vaccination programmes, but the issues of vaccinating boys and older women are increasingly debated.

A comparative analysis of the epidemiological impact and disease cost-savings of HPV vaccines in France

The aim was to compare the epidemiological and economic impact of 16/18 bivalent and 6/11/16/18 quadrivalent HPV vaccination in France, considering differences in licensed outcomes, protection against non-vaccine HPV types and prevention of HPV-6/11-related diseases.

The differential impact of the two vaccines was evaluated using a published model adapted to the French setting. The target population was females aged 14–23 y and the time horizon was 100 y. A total of eight different scenarios compared vaccination impact in terms of reduction in HPV-16/18-associated carcinomas (cervical, vulvar, vaginal, anal, penile and head and neck), HPV-6/11-related genital warts and recurrent respiratory papillomatosis, and incremental reduction in cervical cancer due to potential cross-protection.

Quadrivalent vaccine was associated with total discounted cost savings ranging from EUR 544–1,020 million vs. EUR 177–538 million with the bivalent vaccination (100-y time horizon). Genital wart prevention thanks to quadrivalent HPV vaccination accounted for EUR 306–380 million savings (37–56% of costs saved). In contrast, the maximal assumed cross-protection against cervical cancer resulted in EUR 13–33 million savings (4%). Prevention of vulvar, vaginal and anal cancers accounted for additional EUR 71–89 million savings (13%).

In France, the quadrivalent HPV vaccination would result in significant incremental epidemiological and economic benefits vs. the bivalent vaccination, driven primarily by prevention of genital. The present analysis is the first in the French setting to consider the impact of HPV vaccination on all HPV diseases and non-vaccine types.

Modeling preventative strategies against human papillomavirus-related disease in developed countries

Over the last 5 years, prophylactic vaccination against human papillomavirus (HPV) in pre-adolescent females has been introduced in most developed countries, supported by modeled evaluations that have almost universally found vaccination of pre-adolescent females to be cost-effective. Studies to date suggest that vaccination of pre-adolescent males may also be cost-effective at a cost per vaccinated individual of ~US$400-500 if vaccination coverage in females cannot be increased above ~50%; but if it is possible, increasing coverage in females appears to be a better return on investment. Comparative evaluation of the quadrivalent (HPV16,18,6,11) and bivalent (HPV16,18) vaccines centers around the potential trade-off between protection against anogenital warts and vaccine-specific levels of cross-protection against infections not targeted by the vaccines. Future evaluations will also need to consider the cost-effectiveness of a next generation nonavalent vaccine designed to protect against ~90% of cervical cancers. The timing of the effect of vaccination on cervical screening programs will be country-specific and will depend on vaccination catch-up age range and coverage and the age at which screening starts. Initial evaluations suggest that if screening remains unchanged, it will be less cost-effective in vaccinated compared to unvaccinated women but, in the context of current vaccines, will remain an important prevention method. Comprehensive evaluation of new approaches to screening will need to consider the population-level effects of vaccination over time. New screening strategies of particular interest include delaying the start age of screening, increasing the screening interval and switching to primary HPV screening. Future evaluations of screening will also need to focus on the effects of disparities in screening and vaccination uptake, the potential effects of vaccination on screening participation, and the effects of imperfect compliance with screening recommendations. This article forms part of a special supplement entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.

Population-level impact of the bivalent, quadrivalent, and nonavalent human papillomavirus vaccines: a model-based analysis

BACKGROUND

Bivalent and quadrivalent human papillomavirus (HPV) vaccines are now licensed in several countries. Furthermore, clinical trials examining the efficacy of a nonavalent vaccine are underway. We aimed to compare the potential population-level effectiveness of the bivalent, quadrivalent, and candidate nonavalent HPV vaccines.

METHODS

We developed an individual-based, transmission-dynamic model of HPV infection and disease in a population stratified by age, gender, sexual activity, and screening behavior. The model was calibrated to highly stratified sexual behavior, HPV epidemiology, and cervical screening data from Canada.

RESULTS

Under base case assumptions, vaccinating 12-year-old girls (70% coverage) with the bivalent (quadrivalent) vaccine is predicted to reduce the cumulative incidence of anogenital warts (AGWs) by 0.0% (72.1%), diagnosed cervical intraepithelial neoplasia lesions 2 and 3 (CIN2 and -3) by 51.0% (46.1%), and cervical squamous cell carcinoma (SCC) by 31.9% (30.5%), over 70 years. Changing from a bivalent (quadrivalent) to a nonavalent vaccine is predicted to reduce the cumulative number of AGW episodes by an additional 66.7% (0.0%), CIN2 and -3 episodes by an additional 9.3% (12.5%), and SCC cases by an additional 4.8% (6.6%) over 70 years. Differences in predicted population-level effectiveness between the vaccines were most sensitive to duration of protection and the time horizon of analysis. The vaccines produced similar effectiveness at preventing noncervical HPV-related cancers.

CONCLUSIONS

The bivalent vaccine is expected to be slightly more effective at preventing CIN2 and -3 and SCC in the longer term, whereas the quadrivalent vaccine is expected to substantially reduce AGW cases shortly after the start of vaccination programs. Switching to a nonavalent vaccine has the potential to further reduce precancerous lesions and cervical cancer.

Modeling the impact of the difference in cross-protection data between a human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine and a human papillomavirus (HPV)-6/11/16/18 vaccine in Canada

Background

In Canada, two vaccines that have demonstrated high efficacy against infection with human papillomavirus (HPV) types −16 and −18 are available. The HPV-6/11/16/18 vaccine provides protection against genital warts (GW) while the HPV-16/18 vaccine may provide better protection against other oncogenic HPV types. In this analysis, the estimated clinical and economic benefit of each of these vaccines was compared in the Canadian setting.

Methods

A Markov model of the natural history of HPV infection among women, cervical cancer (CC) and GW was used to estimate the impact of vaccinating a cohort of 100,000 12-year-old females on lifetime outcomes and healthcare system costs (no indirect benefit in males included). A budget impact model was used to estimate the impact of each vaccine by province.

Results

In the base case, vaccination with the HPV-16/18 vaccine was predicted to prevent 48 additional CC cases, and 16 additional CC deaths, while vaccination with the HPV-6/11/16/18 vaccine was predicted to prevent 6,933 additional GW cases. Vaccination with the HPV-16/18 vaccine was estimated to save 1 additional discounted quality adjusted life year (QALY) at an overall lower lifetime cost to the healthcare system compared to the HPV-6/11/16/18 vaccine (assuming vaccine price parity). In sensitivity analyses, the HPV-6/11/16/18 vaccine was associated with greater QALYs saved when the cross-protection efficacy of the HPV-16/18 vaccine was reduced, or the burden of GW due to HPV-6/11 was increased. In most scenarios with price parity, the lifetime healthcare cost of the strategy with the HPV-16/18 vaccine was predicted to be lower than the HPV-6/11/16/18 vaccine. In the probabilistic sensitivity analyses, the HPV-16/18 vaccine provided more QALY benefit than the HPV-6/11/16/18 vaccine in 49.2% of scenarios, with lower relative lifetime costs in 83.5% of scenarios.

Conclusions

Overall, the predicted lifetime healthcare costs and QALYs saved by implementing each of the vaccines are similar. Vaccination with the HPV-16/18 vaccine is expected to be associated with reduced CC disease morbidity and mortality compared to vaccination with the HPV-6/11/16/18 vaccine. Differences in these outcomes depend on the extent of cervical disease prevented by cross-protection and the burden of GW caused by HPV-6/11.

Cross-protective efficacy of two human papillomavirus vaccines: a systematic review and meta-analysis

BACKGROUND

The extent of cross-protection is a key element in the choice of human papillomavirus (HPV) vaccine to use in vaccination programmes. We compared the cross-protective efficacy of the bivalent vaccine (HPV 16 and 18; Cervarix, GlaxoSmithKline Biologicals, Rixensart, Belgium) and quadrivalent vaccine (HPV 6, 11, 16, and 18; Gardasil, Merck, Whitehouse Station, NJ, USA) against non-vaccine type HPVs.

METHODS

We searched Medline and Embase databases, conference abstracts, and manufacturers' websites for randomised clinical trials assessing the efficacy of bivalent and quadrivalent vaccines against persistent infections (lasting ≥6 months) and cervical intraepithelial neoplasia (CIN) associated with the non-vaccine type HPVs (types 31, 33, 45, 52, and 58). We included studies of participants who were HPV DNA negative before vaccination for all HPV types assessed. We assessed heterogeneity in vaccine efficacy estimates between trials with I(2) and χ(2) statistics.

FINDINGS

We identified two clinical trials (Females United to Unilaterally Reduce Endo/Ectocervical Disease [FUTURE] I and II) of the quadrivalent vaccine and three (Papilloma Trial Against Cancer In Young Adults [PATRICIA], HPV007, and HPV-023) of the bivalent vaccine. Analysis of the most comparable populations (pooled FUTURE I/II data vs PATRICIA) suggested that cross-protective vaccine efficacy estimates against infections and lesions associated with HPV 31, 33, and 45 were usually higher for the bivalent vaccine than the quadrivalent vaccine. Vaccine efficacy in the bivalent trial was higher than it was in the quadrivalent trial against persistent infections with HPV 31 (77·1% [95% CI 67·2 to 84·4] for bivalent vaccine vs 46·2% [15·3 to 66·4] for quadrivalent vaccine; p=0·003) and HPV 45 (79·0% [61·3 to 89·4] vs 7·8% [-67·0 to 49·3]; p=0·0003), and against CIN grade 2 or worse associated with HPV 33 (82·3% [53·4 to 94·7] vs 24·0% [-71·2 to 67·2]; p=0·02) and HPV 45 (100% [41·7 to 100] vs -51·9% [-1717·8 to 82·6]; p=0·04). We noted substantial heterogeneity between vaccine efficacy in bivalent trials against persistent infections with HPV 31 (I(2)=69%, p=0·04) and HPV 45 (I(2)=70%, p=0·04), with apparent reductions in cross-protective efficacy with increased follow-up.

INTERPRETATION

The bivalent vaccine seems more efficacious against non-vaccine HPV types 31, 33, and 45 than the quadrivalent vaccine, but the differences were not all significant and might be attributable to differences in trial design. Efficacy against persistent infections with types 31 and 45 seemed to decrease in bivalent trials with increased follow-up, suggesting a waning of cross-protection; more data are needed to establish duration of cross-protection.

FUNDING

Public Health Agency of Canada.