Bacterially expressed human papillomavirus type 6 and 11 bivalent vaccine: Characterization, antigenicity and immunogenicity.

Human papillomavirus (HPV)-6 and HPV11 are the major etiological causes of condylomata acuminate. HPV neutralization by vaccine-elicited neutralizing antibodies can block viral infection and prevent subsequent disease. Currently, two commercially available HPV vaccines cover these two genotypes, expressed by Saccharomyces cerevisiae. Here we describe another HPV6/11 bivalent vaccine candidate derived from Escherichia coli. The soluble expression of N-terminally truncated L1 proteins was optimized to generate HPV6- and HPV11 L1-only virus-like particles (VLPs) as a scalable process. In a pilot scale, we used various biochemical, biophysical and immunochemical approaches to comprehensively characterize the scale and lot consistency of the vaccine candidate at 30L and 100L. Cryo-EM structure analysis showed that these VLPs form a T=7 icosahedral lattice, imitating the L1 capsid of the authentic HPV virion. This HPV6/11 bivalent vaccine confers a neutralization titer and antibody production profile in monkey that is comparable with the quadrivalent vaccine, Gardasil. This study demonstrates the robustness and scalability of a potential HPV6/11 bivalent vaccine using a prokaryotic system for vaccine production.

Cost-effectiveness analysis of AS04-adjuvanted human papillomavirus 16/18 vaccine compared with human papillomavirus 6/11/16/18 vaccine in the Philippines, with the new 2-dose schedule.

Cervical cancer (CC) is the second leading cause of cancer death among Filipino women. Human papillomavirus (HPV) vaccination protects against CC. Two vaccines (AS04-HPV-16/18 and 4vHPV) are approved in the Philippines; they were originally developed for a 3-dose (3D) administration and have recently been approved in a 2-dose schedule (2D). This study aims to evaluate the cost-effectiveness of HPV vaccination of 13-year-old Filipino girls, in addition to current screening, in the new 2D schedule. An existing static lifetime, one-year cycle Markov cohort model was adapted to the Philippine settings to simulate the natural history of low-risk and oncogenic HPV infection, the effects of screening and vaccination of a 13-year-old girls cohort vaccinated with either the 2D-AS04-HPV-16/18 or 2D-4vHPV assuming a 100% vaccination coverage. Incremental cost, quality-adjusted life year (QALY) and cost-effectiveness were derived from these estimates. Input data were obtained from published sources and Delphi panel, using country-specific data where possible. Sensitivity analyses were performed to assess the robustness of the model. The model estimated that 2D-AS04-HPV-16/18 prevented 986 additional CC cases and 399 CC deaths (undiscounted), as well as 555 increased QALY (discounted), and save 228.1 million Philippine pesos (PHP) compared with the 2D-4vHPV. In conclusion, AS04-HPV-16/18 is shown to be dominant over 4vHPV in the Philippines, with greater estimated health benefits and lower costs.

Next generation prophylactic human papillomavirus vaccines.

The two licensed bivalent and quadrivalent human papillomavirus (HPV) L1 (the major papillomavirus virion protein) virus-like particle (VLP) vaccines are regarded as safe, effective, and well established prophylactic vaccines. However, they have some inherent limitations, including a fairly high production and delivery cost, virus-type restricted protection, and no reported therapeutic activity, which might be addressed with the development of alternative dosing schedules and vaccine products. A change from a three-dose to a two-dose protocol for the licensed HPV vaccines, especially in younger adolescents (aged 9-13 years), is underway in several countries and is likely to become the future norm. Preliminary evidence suggests that recipients of HPV vaccines might derive prophylactic benefits from one dose of the bivalent vaccine. Substantial interest exists in both the academic and industrial sectors in the development of second-generation L1 VLP vaccines in terms of cost reduction-eg, by production in Escherichia coli or alternative types of yeast. However, Merck's nonavalent vaccine, produced via the Saccharomyces cerevisiae production system that is also used for their quadrivalent vaccine, is the first second-generation HPV VLP vaccine to be available on the market. By contrast, other pharmaceutical companies are developing microbial vectors that deliver L1 genes. These two approaches would add an HPV component to existing live attenuated vaccines for measles and typhoid fever. Prophylactic vaccines that are based on induction of broadly cross-neutralising antibodies to L2, the minor HPV capsid protein, are also being developed both as simple monomeric fusion proteins and as virus-like display vaccines. The strong interest in developing the next generation of vaccines, particularly by manufacturers in middle-to-high income countries, increases the likelihood that vaccine production will become decentralised with the hope that effective HPV vaccines will be made increasingly available in low-resource settings where they are most needed.

Health economic analysis of human papillomavirus vaccines in women of Chile: perspective of the health care payer using a Markov model.

BACKGROUND: In Chile, significant reductions in cervical cancer incidence and mortality have been observed due to implementation of a well-organized screening program. However, it has been suggested that the inclusion of human papillomavirus (HPV) vaccination for young adolescent women may be the best prospect to further reduce the burden of cervical cancer. This cost-effectiveness study comparing two available HPV vaccines in Chile was performed to support decision making on the implementation of universal HPV vaccination. METHODS: The present analysis used an existing static Markov model to assess the effect of screening and vaccination. This analysis includes the epidemiology of low-risk HPV types allowing for the comparison between the two vaccines (HPV-16/18 AS04-adjuvanted vaccine and the HPV-6/11/16/18 vaccine), latest cross-protection data on HPV vaccines, treatment costs for cervical cancer, vaccine costs and 6% discounting per the health economic guideline for Chile. RESULTS: Projected incremental cost-utility ratio (ICUR) and incremental cost-effectiveness ratio (ICERs) for the HPV-16/18 AS04-adjuvanted vaccine was 116 United States (US) dollars per quality-adjusted life years (QALY) gained or 147 US dollars per life-years (LY) saved, while the projected ICUR/ICER for the HPV-6/11/16/18 vaccine was 541 US dollars per QALY gained or 726 US dollars per LY saved. Introduction of any HPV vaccine to the present cervical cancer prevention program of Chile is estimated to be highly cost-effective (below 1X gross domestic product [GDP] per capita, 14278 US dollars). In Chile, the addition of HPV-16/18 AS04-adjuvanted vaccine to the existing screening program dominated the addition of HPV-6/11/16/18 vaccine. In the probabilistic sensitivity analysis results show that the HPV-16/18 AS04-adjuvanted vaccine is expected to be dominant and cost-saving in 69.3% and 77.6% of the replicates respectively. CONCLUSIONS: The findings indicate that the addition of any HPV vaccine to the current cervical screening program of Chile will be advantageous. However, this cost-effectiveness model shows that the HPV-16/18 AS04-adjuvanted vaccine dominated the HPV-6/11/16/18 vaccine. Beyond the context of Chile, the data from this modelling exercise may support healthcare policy and decision-making pertaining to introduction of HPV vaccination in similar resource settings in the region.

Estimating the incidence and prevalence of juvenile-onset recurrent respiratory papillomatosis in publicly and privately insured claims databases in the United States.

BACKGROUND: Juvenile-onset recurrent respiratory papillomatosis (JORRP) is a chronic disease caused by human papillomavirus types 6 and 11. It is associated with significant morbidity that places intense physical, psychological, and financial strain on patients and their families. Few studies have assessed the incidence and prevalence of JORRP in the United States. METHODS: This retrospective, longitudinal cohort study was performed using data from a pair of large insurance claims databases in the United States. The Optum Clinformatics and Truven MarketScan Medicaid databases represent a sample of privately and publicly insured children, respectively. Cohorts of children aged 0 to 17 years were created within each database to estimate the incidence and prevalence of JORRP in 2006. Claims-based algorithms were designed to capture as many potential cases as possible. To improve the accuracy of the incidence and prevalence estimates, chart validation was performed to estimate the positive predictive value (PPV) of the claims-based algorithms. RESULTS: The overall PPV-adjusted incidence of JORRP in 2006 was 0.51 per 100,000 in Optum and 1.03 per 100,000 in the MarketScan Medicaid population. Peak incidence was observed among 0- to 4-year-olds in both databases. The PPV-adjusted prevalence of JORRP in 2006 was 1.45 and 2.93 per 100,000 in the Optum and MarketScan Medicaid cohorts, respectively. CONCLUSIONS: Although relatively uncommon, JORRP represents a disease with significant morbidity. The incidence and prevalence of JORRP in publicly insured children were consistently higher than those covered by private insurance plans, suggesting an increased burden of illness among those with lower socioeconomic status.

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.

HPV 6, 11, 16, 18 vaccine in men. Inadequate assessment.

In a trial including 4065 men aged 16 to 26 years, HPV 6, 11, 16, 18 vaccination reduced the incidence of anogenital warts, but the preventive effect on cancer remains to be demonstrated.

Cost-effectiveness analysis of the bivalent compared with the quadrivalent human papillomavirus vaccines in Taiwan.

OBJECTIVE: To compare the epidemiological and economic impact of additional cross-protection against oncogenic human papillomavirus (HPV) types beyond 16/18 of the bivalent vaccine (BV) versus protection against nononcogenic HPV types 6/11 of the quadrivalent vaccine (QV) in Taiwan. METHODS: A lifetime Markov model calibrated to the Taiwanese setting simulated the natural history of low-risk (engendering cervical intraepithelial neoplasia [CIN] 1 and genital warts) and high-risk HPV (engendering CIN1, CIN2/3, and cervical cancer [CC]) infections, screening, and vaccination (100% coverage) for a cohort of 12-year-old girls (N = 153,000). Transition probabilities, costs, and utilities were estimated from published data and expert opinion. Vaccine efficacy was obtained from each vaccine's respective clinical trials. Price-parity and lifelong protection was assumed for both vaccines. The number of CIN lesions, CC cases, CC deaths and genital wart (GW) cases, and quality-adjusted life-years were estimated. Costs and outcomes (discounted at 3% and 1.5%, respectively) were compared from a payer's perspective. RESULTS: The model estimated that the BV led to an additional, undiscounted, 11,484 CIN1, 1,779 (+34.3% vs. QV) CIN2/3, 188 (+29.0% vs. QV) CC, and 69 (+29.0% vs. QV) CC deaths prevented compared with the QV, while the QV prevented 4,150 GW (+71%). This resulted in an additional 768 quality-adjusted life-years (QALY) and 11.6 million new Taiwan dollars costs saved for the BV versus the QV after discounting. CONCLUSION: Both vaccines have a different epidemiological impact with an increased number of CC-related lesions potentially prevented for the BV because of additional cross-protection. In the Taiwanese setting, HPV mass vaccination using the BV was estimated to dominate vaccination using the QV.

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

OBJECTIVES: Two human papillomavirus (HPV) vaccines are currently available: a bivalent HPV-16/18 and a quadrivalent HPV-6/11/16/18 vaccine. The vaccines may have different sustained- and cross-protection levels against non-vaccine oncogenic HPV-types. This study investigated the potential difference in clinical and economic impacts provided by two HPV vaccines in Italy. METHODS: A prevalence-based model estimated the potential net difference in HPV-related lesions (abnormal pap smear, cervical intraepithelial neoplasia (CIN), cervical cancer (CC) and genital warts (GW)) and associated costs generated by the two vaccines. Incidence and treatment costs were obtained from Italian and European sources. Vaccine efficacy rates were based on published data for each vaccine. Lifetime vaccine efficacy was assumed. Results are reported over one year after reaching a steady state. Sensitivity analyses were performed on the lesion incidence, vaccine effectiveness, treatment costs and sustained protection. RESULTS: The bivalent vaccine would prevent an additional reduction of 7976 abnormal pap smears; 601 CIN1; 1826 CIN2/3 and 295 CC cases compared to the quadrivalent vaccine while 25,848 genital wart cases would be prevented by the quadrivalent vaccine. The additional cost averted with the bivalent vaccine was estimated at €2,385,354 per year compared to the quadrivalent vaccine. The most influential parameters were CC- and GW-related costs and the difference in sustained protection. CONCLUSIONS: Our model suggests that, in the Italian setting, the bivalent vaccine would prevent more precancerous and CC lesions than the quadrivalent vaccine. This translates into a greater cost averted for the bivalent vaccine, which could completely offset savings in GW-related costs associated with the quadrivalent vaccine.

Integrating clinical, community, and policy perspectives on human papillomavirus vaccination.

Infection with genital human papillomavirus (HPV) may cause anogenital cancers, oropharyngeal cancers, anogenital warts, and respiratory papillomas. Two prophylactic vaccines (a bivalent and a quadrivalent vaccine) are now licensed and currently in use in a number of countries. Both vaccines prevent infection with HPV-16 and HPV-18, which together cause approximately 70% of cervical cancers, and clinical trials have demonstrated 90%-100% efficacy in preventing precancerous cervical lesions attributable to HPV-16 and HPV-18. One vaccine also prevents HPV-6 and HPV-11, which cause 90% of genital warts. A growing literature describes psychosocial, interpersonal, organizational, and societal factors that influence HPV vaccination acceptability. This review summarizes the current literature and presents an integrated perspective, taking into account these diverse influences. The resulting integrated framework can be used as a heuristic tool for organizing factors at multiple levels to guide intervention development and future research.