Noninferiority of antibody response to human papillomavirus type 16 in subjects vaccinated with monovalent and quadrivalent L1 virus-like particle vaccines

Definition and rationale for placebo composition: Cross-sectional analysis of randomized trials and protocols published in high-impact medical journals

BACKGROUND/AIMS

Inadequate description of trial interventions in publications has been repeatedly reported, a problem that extends to the description of placebo controls. Without describing placebo contents, it cannot be assumed that a placebo is inert. Pharmacologically active placebos complicate accurate estimation and interpretation of efficacy and safety data. In this study, we sought to assess whether placebo contents are described in study protocols and publications of trials published in high-impact medical journals.

METHODS

We identified all placebo-controlled randomized clinical trials (RCTs) published in 2016 in Annals of Internal Medicine, The BMJ, the Journal of the American Medical Association (JAMA), The Lancet, and the New England Journal of Medicine (NEJM). We included all trials with publicly available study protocols. From journal publications and associated study protocols, we searched and recorded: description of placebo contents; the amount of each placebo ingredient; and investigators' stated rationale for selection of placebo ingredients.

RESULTS

We included 113 placebo-controlled RCTs. Of the 113 trials, placebo content was described in 22 (19.5%) journal publications and 51 (45.1%) study protocols. The amount of each placebo ingredient was described in 15 (13.3%) journal publications and 47 (41.6%) study protocols. None of the journal publications explained the rationale for the choice of placebo ingredients, whereas a rationale was provided in 4 (3.5%) study protocols. The stated rationales were to ensure the placebo was visually indistinguishable from the experimental intervention (N = 3) and ensure comparability with a previous study (N = 1).

CONCLUSION

There is no accessible record of the composition of placebos for approximately half of high-impact RCTs, even with access to study protocols. This impedes reproducibility and raises unanswerable questions about what effects-beneficial or harmful-the placebo may have had on trial participants, potentially confounding an accurate assessment of the experimental intervention's safety and efficacy. Considering that study protocols are unabridged, detailed documents describing the trial design and methodology, the fact that less than half of the study protocols described the placebo contents raises concerns about clinical trial transparency. To improve the reproducibility and potential of placebo-controlled RCTs to provide reliable evidence on the efficacy and safety profile of drugs and other experimental interventions, more detail regarding placebo contents must be included in trial documents.

Human papillomavirus seroprevalence and seroconversion following baseline detection of nine human papillomavirus types in young women

Background

Estimates of the humoral immune response to incident human papillomavirus (HPV) infections are limited.

Methods

In this post hoc analysis of 3875 women aged 16–23 years from a 4-valent HPV vaccine trial (NCT00092482), HPV seroprevalence on day 1 was measured with a 9-valent HPV (HPV 6/11/16/18/31/33/45/52/58) competitive Luminex immunoassay and compared with cervical/external genital HPV detection by polymerase chain reaction. In the control group, among women who were HPV DNA‒negative on day 1, seroconversion following initial HPV detection was estimated using Kaplan-Meier methods.

Results

Type-specific HPV seropositivity among women with no day 1 cervical/external genital HPV detection was 0.6%–3.6%. Women with any 9-valent HPV (9vHPV) cervical/external genital detection (796/3875; 20.5%) had concordant seropositivity ranging from 13.4% (HPV 45) to 38.5% (HPV 6). Among women in the control group who were negative for all HPV types on day 1, seroconversion by month 30 after initial detection ranged from 29% (HPV 45) to 75% (HPV 16).

Conclusions

Humoral immune response to HPV is variable and dynamic, depending on type-specific exposure. This longitudinal analysis provides insight into the relationship between incident infection and seropositivity.

ClinicalTrials.gov; NCT00092482 https://clinicaltrials.gov/ct2/show/NCT00092482.

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Research on humoral immune responses to HPV infection are limited.

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HPV-related serologic responses were analyzed in women aged 16–23 years.

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Type-specific HPV seropositivity was low in women without initial HPV DNA detection.

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Concordant seropositivity in women with any 9vHPV DNA detection ranged from 13% to 40%.

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Seroconversion to the same genotype within 30 months of an infection was common.

Adjuvant-containing control arms in pivotal quadrivalent human papillomavirus vaccine trials: restoration of previously unpublished methodology

PURPOSE

Trustworthy reporting of quadrivalent human papillomavirus (HPV) vaccine trials is the foundation for assessing the vaccine's risks and benefits. However, several pivotal trial publications incompletely reported important methodological details and inaccurately described the formulation that the control arms received. Under the Restoring Invisible and Abandoned Trials initiative (RIAT), we aim to restore the public record regarding the content and rationale of the controls used in the trials.

METHODS

We assembled a cohort (five randomised controlled trials) described as placebo-controlled using clinical study reports (CSRs) obtained from the European Medicines Agency. We extracted the content and rationale for the choice of control used in each trial across six data sources: trial publications, register records, CSR synopses, CSR main bodies, protocols and informed consent forms.

RESULTS

Across data sources, the control was inconsistently reported as 'placebo'-containing aluminium adjuvant (sometimes with dose information). Amorphous aluminium hydroxyphosphate sulfate (AAHS) was not mentioned in any trial registry entry, but was mentioned in all publications and CSRs. In three of five trials, consent forms described the control as an 'inactive' substance. No rationale for the selection of the control was reported in any trial publication, register, consent form, CSR synopsis or protocol. Three trials reported the rationale for choice of control in CSRs: to preserve blinding and assess the safety of HPV virus-like particles as the 'safety profile of (AAHS) is well characterised'.

CONCLUSIONS

The stated rationale of using AAHS control-to characterise the safety of the HPV virus-like particles-lacks clinical relevance. A non-placebo control may have obscured an accurate assessment of safety and the participant consent process of some trials raises ethical concerns.

TRIAL REGISTRATION NUMBERS

NCT00092482, NCT00092521, NCT00092534, NCT00090220, NCT00090285.

Minor Capsid Protein L2 Polytope Induces Broad Protection against Oncogenic and Mucosal Human Papillomaviruses

The amino terminus of the human papillomavirus (HPV) minor capsid protein L2 contains a major cross-neutralization epitope which provides the basis for the development of a broadly protecting HPV vaccine. A wide range of protection against different HPV types would eliminate one of the major drawbacks of the commercial, L1-based prophylactic vaccines. Previously, we have reported that insertion of the L2 epitope into a scaffold composed of bacterial thioredoxin protein generates a potent antigen inducing comprehensive protection against different animal and human papillomaviruses. We also reported, however, that although protection is broad, some oncogenic HPV types escape the neutralizing antibody response, if L2 epitopes from single HPV types are used as immunogen. We were able to compensate for this by applying a mix of thioredoxin proteins carrying L2 epitopes from HPV16, -31, and -51. As the development of a cost-efficient HPV prophylactic vaccines is one of our objectives, this approach is not feasible as it requires the development of multiple good manufacturing production processes in combination with a complex vaccine formulation. Here, we report the development of a thermostable thioredoxin-based single-peptide vaccine carrying an L2 polytope of up to 11 different HPV types. The L2 polytope antigens have excellent abilities in respect to broadness of protection and robustness of induced immune responses. To further increase immunogenicity, we fused the thioredoxin L2 polytope antigen with a heptamerization domain. In the final vaccine design, we achieve protective responses against all 14 oncogenic HPV types that we have analyzed plus the low-risk HPVs 6 and 11 and a number of cutaneous HPVs.IMPORTANCE Infections by a large number of human papillomaviruses lead to malignant and nonmalignant disease. Current commercial vaccines based on virus-like particles (VLPs) effectively protect against some HPV types but fail to do so for most others. Further, only about a third of all countries have access to the VLP vaccines. The minor capsid protein L2 has been shown to contain so-called neutralization epitopes within its N terminus. We designed polytopes comprising the L2 epitope amino acids 20 to 38 of up to 11 different mucosal HPV types and inserted them into the scaffold of thioredoxin derived from a thermophile archaebacterium. The antigen induced neutralizing antibody responses in mice and guinea pigs against 26 mucosal and cutaneous HPV types. Further, addition of a heptamerization domain significantly increased the immunogenicity. The final vaccine design comprising a heptamerized L2 8-mer thioredoxin single-peptide antigen with excellent thermal stability might overcome some of the limitations of the current VLP vaccines.

Humoral Immune Response Against Human Papillomavirus as Source of Biomarkers for the Prediction and Detection of Cervical Cancer

Cervical cancer (CC) is one of the main causes of death among women of reproductive age. Although there are different tests, the disease tends to be diagnosed at late stages. In recent years, the use of complementary tests or sequential diagnostic tests has been implemented. Nevertheless, the results are variable and not conclusive; therefore, more studies for improving the usefulness of these tests in diagnostics are necessary. The human papillomavirus (HPV) infection has been associated with both benign and malignant proliferation of skin and mucosal tissues. Furthermore, some HPV types have been classified as high risk due to their potential to cause cancer, and HPV16 is most frequently associated with this disease. Although between 70% and 80% of precancerous lesions are eliminated by the host's immune system, there is no available test to distinguish between regressive lesions from those that could progress to CC. An HPV infection generates a humoral immune response against L1 and L2 capsid proteins, which can be protective and a response against early proteins. The latter is not a protective response, but these antibodies can be used as markers to determine the stage of the infection and/or the stage of the cervical lesion. Up to now, the humoral immune response resulting from the HPV infection has been used to study the biology of the virus and the efficacy of the HPV vaccines. Although there are no conclusive results regarding the use of these antibodies for diagnosis, we hereby review the actual panorama of the antibody response against the HPV proteins during the development of the disease as well as their possible use as biomarkers for the progression of cervical lesions and of CC.

Quadrivalent human papillomavirus (types 6, 11, 16, 18) recombinant vaccine (gardasil(®)): a review of its use in the prevention of premalignant anogenital lesions, cervical and anal cancers, and genital warts

Quadrivalent human papillomavirus (HPV) [types 6, 11, 16, 18] recombinant vaccine (Gardasil(®); Silgard(®)) is composed of virus-like particles formed by self-assembly of recombinant L1 capsid protein from each of HPV types 6, 11, 16 and 18. It is indicated for use from the age of 9 years as a two- or three-dose vaccination course over 6 months for the prevention of premalignant anogenital lesions, cervical and anal cancers, and genital warts caused by the vaccine HPV types. In placebo-controlled trials, quadrivalent HPV vaccine provided high-level protection against infection or disease caused by the vaccine HPV types over 2-4 years in females aged 15-45 years who were negative for the vaccine HPV types, and provided a degree of cross-protection against certain non-vaccine HPV types. The vaccine also provided high-level protection against persistent infection, anogenital precancerous lesions and genital warts caused by the vaccine HPV types over 3 years in susceptible males aged 16-26 years. Protection has been demonstrated for up to 8 years. In subjects who were negative for the vaccine HPV types, high seroconversion rates and high levels of anti-HPV antibodies were observed in females of all age ranges from 9 to 45 years and in males aged 9-26 years. The vaccine was generally well tolerated and was usually predicted to be cost effective in girls and young women. Therefore, quadrivalent HPV vaccine offers an effective means to substantially reduce the burden of HPV-related anogenital disease in females and males, particularly cervical cancer and genital warts.

Clinical trial experience with prophylactic human papillomavirus 6/11/16/18 vaccine in young black women

PURPOSE

Human papillomavirus (HPV) is the causative agent of cervical cancer. Black women are disproportionally diagnosed and have higher mortality from cervical cancer in the United States. Here we describe the prophylactic efficacy and safety of a quadrivalent HPV-6/11/16/18 vaccine in black women.

METHODS

A total of 700 black women from Latin America, Europe, and North America (aged 16-24 years) received the vaccine or placebo in one of two studies. Analyses focused on the efficacy and safety of the vaccine.

RESULTS

Baseline rates of Chlamydia trachomatis infection and history of past pregnancy were more than twice as high in black women compared with the non-black women who were enrolled in these trials. HPV-6/11/16 or 18 DNA was detected in 18% of black women versus 14.6% in non-black women at day 1. For black women, vaccine efficacy against disease caused by HPV-6/11/16/18 was 100% for cervical intraepithelial neoplasia (0 vs. 15 cases; 95% confidence interval, 64.5%-100%) and 100% for vulvar and vaginal intraepithelial neoplasia and condylomata acuminata (0 vs. 17 cases; 95% confidence interval, 69.3%-100%). There were no serious vaccine-related adverse experiences. A similar proportion of pregnancies resulted in live births (75.8% vaccine; 72.7% placebo) and fetal loss (24.2% vaccine; 27.3% placebo).

CONCLUSIONS

Prophylactic quadrivalent HPV-6/11/16/18 vaccination of young black women demonstrated high efficacy, safety, and tolerability. HPV vaccination has the potential to reduce cervical cancer-related health disparities both in the United States and around the world.

Spotlight on quadrivalent human papillomavirus (types 6, 11, 16, 18) recombinant vaccine(Gardasil®) 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 programs, to substantially reduce the burden of HPV-related precancerous lesions and cancer, particularly cervical cancer, as well as anogenital warts.

Co-administration of human papillomavirus-16/18 AS04-adjuvanted vaccine with hepatitis B vaccine: randomized study in healthy girls

BACKGROUND

To evaluate co-administration of GlaxoSmithKline Biologicals' human papillomavirus-16/18 AS04-adjuvanted vaccine (HPV) and hepatitis B vaccine (HepB).

METHODS

This was a randomized, controlled, open, multicenter study. Healthy girls, aged 9-15 years, were randomized to receive HPV (n=247), HepB (n=247) or HPV co-administered with HepB (HPV+HepB; n=247) at Months 0, 1 and 6. Antibodies against hepatitis B surface antigen (HBs), HPV-16 and HPV-18 were measured, and reactogenicity and safety monitored. Co-primary objectives were to demonstrate non-inferiority of hepatitis B and HPV-16/18 immune responses at Month 7 for co-administered vaccines, compared with vaccines administered alone, in the according-to-protocol cohort.

RESULTS

The pre-defined criteria for non-inferiority were met for all co-primary immunogenicity endpoints at Month 7. Anti-HBs seroprotection rates ≥10mIU/mL were achieved by 97.9% and 100% of girls, respectively, following co-administration or HepB alone. Anti-HBs geometric mean titers (GMTs) (95% confidence interval) were 1280.9 (973.3-1685.7) and 3107.7 (2473.1-3905.1) milli-international units/mL, respectively. Anti-HPV-16 and -18 seroconversion rates were achieved by ≥99% of girls following co-administration or HPV alone. Anti-HPV-16 GMTs were 19819.8 (16856.9-23303.6) and 21712.6 (19460.2-24225.6) ELISA units (ELU)/mL, respectively. Anti-HPV-18 GMTs were 8835.1 (7636.3-10222.1) and 8838.6 (7948.5-9828.4) ELU/mL, respectively. Co-administration was generally well tolerated.

CONCLUSIONS

The study results support the co-administration of HPV-16/18 AS04-adjuvanted vaccine with hepatitis B vaccine in adolescent girls aged 9-15 years.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov registration number NCT00652938.

Incident cervical HPV infections in young women: transition probabilities for CIN and infection clearance

BACKGROUND

We describe transition probabilities for incident human papillomavirus (HPV) 16/18/31/33/35/45/52/58/59 infections and cervical intraepithelial neoplasia (CIN) 1 lesions.

METHODS

Women ages 16 to 23 years underwent cytology and cervical swab PCR testing for HPV at approximately 6-month intervals for up to 4 years in the placebo arm of an HPV vaccine trial. The cumulative proportion of incident HPV infections with diagnosed CIN, clearing (infection undetectable), or persisting without CIN, were estimated.

RESULTS

Most incident infections cleared, without detection of CIN, ranging at 36 months from 66.9% for HPV31 to 91.1% for HPV59. There was little variation in the 36-month proportion of incident HPV16, 18, and 31 infections followed by a CIN1 lesion positive for the relevant HPV type (range 16.7%-18.6%), with lower risks for HPV59 (6.4%) and HPV33 (2.9%). Thirty-six-month transition probabilities for CIN2 ranged across types from 2.2% to 9.1%; however, the number of events was generally too small for statistically significant differences to be seen across types for this endpoint, or CIN3.

CONCLUSIONS

Some incident HPV types appear more likely to result in diagnosed CIN1 than others. The relative predominance of HPV16, vis-à-vis some other high-risk HPV types (e.g., HPV33) in prevalent CIN2/3, appears more directly associated with relatively greater frequency of incident HPV16 infections within the population, than a higher risk of infection progression to CIN2/3.

IMPACT

Nearly all incident HPV infections either manifest as detectable CIN or become undetectable within 36 months. Some HPV types (e.g., 16 and 33) appear to have similar risk of CIN2/3 despite widely varied incidence.

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.

Incidence, duration, and reappearance of type-specific cervical human papillomavirus infections in young women

BACKGROUND

We describe the incidence and duration of cervical human papillomavirus (HPV) infection episodes along with the risk of infection reappearance following a period of nondetection.

METHODS

Women (1,788) ages 16 to 23 years underwent cytologic testing and PCR-based testing of cervical swab samples for HPV DNA (HPV-16/18/31/33/35/45/52/58/59) at approximately 6-month intervals for up to 4 years in the context of a phase 3 clinical trial (placebo arm). HPV type-specific incidence rates were estimated per 100 person-years. Duration of type-specific cervical infection episodes and risk of reappearance following a period of nondetection were estimated using Kaplan-Meier methods.

RESULTS

HPV-16 exhibited the highest (5.9), and HPV-35 and HPV-33 exhibited the lowest (1.0) incidence rates per 100 person-years. Mean cervical infection durations ranged from 13 months for HPV-59 to 20 months for HPV-16 and 58 (with ongoing infections censored at the time of treatment, if done). The risk of cervical infection reappearance within approximately 3 years following a period of nondetection ranged from 0% to 16% across HPV types, with a mean of 8%. Limited evidence was found for a role of false-positive HPV tests, missed infections that were above the threshold for detection, or new acquisition of infection in accounting for patterns of infection reappearance.

CONCLUSIONS

Incidence of high-risk cervical infection was observed to vary considerably more across HPV types than infection duration. A nontrivial proportion of women exhibited infection reappearance following a period of nondetection, with a potential explanation for many such events observed within this analysis being a return to detectable levels of a previously acquired infection.

IMPACT

The risk of HPV infection reappearance following a period of nondetection has not been previously reported for individual HPV types, and this study finds that a nontrivial proportion of infected women exhibit reappearances. Future studies could ascertain subject-level factors that potentially modify the risk of infection reappearance.

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.

Prevalence of human papillomavirus types 6, 11, 16 and 18 in young Austrian women - baseline data of a phase III vaccine trial

INTRODUCTION

Cervical cancer is the second most common cancer among women worldwide. In the absence of changing risk or intervention, it is projected that in comparison with 2002 there will be a 40% increase in the number of new cases of cervical cancer by 2020. HPV types 16 and 18 cause 70% of cervical cancers worldwide, 50% of high-grade cervical intraepithelial neoplasias and 25% of low-grade neoplasias. HPV types 6 and 11 are the causative agent of > 90% of genital warts. The aim of this study was to assess the baseline prevalence of infection with HPV 6, 11, 16 and 18 in young Austrian women.

METHODS

Austrian females aged 16-24 (n = 123) were enrolled in a double-blind, placebo-controlled, randomized phase III trial of a quadrivalent HPV (types 6, 11, 16, 18) vaccine (FUTURE I, ClinicalTrials.gov number NCT00092521). Healthy women who were not pregnant and had no prior history of genital warts or abnormal results on cervical cytologic testing and had fewer than five lifetime sex partners were eligible for enrollment. The study sub-population was recruited primarily from university settings.

RESULTS

Analysis of the sexual history of the Austrian subjects showed that 92.7% (114/123) were non-virgins and 46.3% were current smokers. At enrollment, 15 (13.5%) had positive serological or PCR tests for HPV 6, 11, 16 or 18. Serologically, 14 (12.3%) of women were positive to HPV 6, 11, 16 or 18: of these, 13 (11.4%) were positive for HPV 16, four (3.5%) were positive for HPV 18, and one (0.9%) for HPV 6. By PCR all were negative for HPV 6 and 11, whereas seven (6.1%) were positive for HPV 16 and one (0.9%) for HPV 18. Abnormal cytology was observed in 12 (10.3%) women.

DISCUSSION

Although the prevalence of vaccine HPV types among young Austrian women with fewer than five lifetime sexual partners was lower than in international data, we observed a high prevalence of abnormal cytology and smoking. These data suggest that a substantial number of Austrian women are at risk for HPV-related disease.

Virus-like particles and capsomeres are potent vaccines against cutaneous alpha HPVs

The potential as prophylactic vaccines of L1-based particles from cutaneous genus alpha human papillomavirus (HPV) types has not been assessed so far. However, there is a high medical need for such vaccines since HPV-induced skin warts represent a major burden for children and for immunocompromised adults, such as organ transplant recipients. In this study, we have examined the immunogenicity of capsomeres and virus-like particles (VLPs) from HPV types 2, 27, and 57, the most frequent causative agents of skin warts. Immunization of mice induced immune responses resembling those observed upon vaccination with HPV 16 L1-based antigens. The antibody responses were cross-reactive but type-restricted in their neutralizing capacities. Application of adjuvant led to an enhanced potential to neutralize the respective immunogen type but did not improve cross-neutralization. Vaccination with capsomeres and VLPs from all four analyzed HPV types induced robust IFNgamma-associated T-cell activation. Immunization with mixed VLPs from HPV types 2, 27, and 57 triggered an antibody response similar to that after single-type immunization and capable of efficiently neutralizing all three types. Our results imply that vaccination with combinations of VLPs from cutaneous HPV types constitutes a promising strategy to prevent HPV-induced skin lesions.

Human papillomavirus infections and vulvar disease development

BACKGROUND

We describe the prevalence of 14 common types [human papillomavirus (HPV)-6/11/16/18/31/33/35/39/45/51/52/56/58/59] in vulvar intraepithelial neoplasia grades 1 to 3 (VIN 1-3) and HPV genotype-specific infection in relation to the development of VIN 1-3.

METHODS

Data were analyzed from women enrolled in the placebo arms of three randomized double-blind trials. Anogenital examinations, including collection of labial/vulvar/perineal/perianal swabs, occurred at day 1 and every 6 to 12 months through 48 months. Lesions that were possibly, probably, or definitely HPV related or of unknown etiology were biopsied. Biopsies and swabs were HPV typed. Biopsies were read for endpoint determination (VIN 1-3) by up to four pathologists.

RESULTS

Incident infection with HPV-16 was the most common (6.0/100 person-years). The mean time from incident infection to the development of VIN 1-3 was 18.5 months (95% confidence interval, 13.4-23.6). HPV-6 or -11 was observed in 64.5% of VIN 1 and 29.0% of VIN 2/3, whereas HPV-16 was observed in 6.5% of VIN 1 and 64.5% of VIN 2/3.

CONCLUSION

A vaccine that includes both low- and high-risk types could prevent more than half of VIN 1-3 lesions, including the precursor lesions to HPV-related vulvar carcinoma. Understanding the incidence and duration of vulvar HPV infection and risk for progression to VIN 1-3 may inform therapeutic decisions for vulvar disease and mathematical models that assess the cost-effectiveness of vaccination.

[Nobel price for vaccination against cervical cancer: current data and guidelines]

Harald zur Hausen received the Nobel price for Medicine in 2008 for his seminal research on human papilloma viruses and their association with anogenital diseases. On the basis of his work highly effective prophylactic vaccines have been developed. Clinical studies have shown nearly 100% seroconversion and an excellent safety profile as well as greater than 96% efficacy against HPV infection and premalignant dysplasia, induced by HPV types covered by the vaccine. Due to the convincing data of phase II and III clinical trials the introduction of HPV vaccination was recommended by health authorities and scientific committees in Germany. The development and availability of guidelines and evidence-based recommendations should support the introduction of the vaccine and widespread vaccination.

Alphavirus-adjuvanted norovirus-like particle vaccines: heterologous, humoral, and mucosal immune responses protect against murine norovirus challenge

The development of an effective norovirus vaccine likely requires the capacity to protect against infection with multiple norovirus strains. Advanced recombinant genetic systems and the recent discovery of a mouse-tropic norovirus strain (MNV) provide robust model systems for vaccine efficacy studies. We coadministered multivalent norovirus-like particle (VLP) vaccines with alphavirus adjuvant particles to mice and evaluated homotypic and heterotypic humoral and protective immunity to human and murine norovirus strains. Multivalent VLP vaccines induced robust receptor-blocking antibody responses to heterologous human strains not included in the vaccine composition. Inclusion of alphavirus adjuvants in the inoculum significantly augmented VLP-induced systemic and mucosal immunity compared to the responses induced by low-dose CpG DNA, validating the utility of such adjuvants with VLP antigens. Furthermore, multivalent vaccination, either including or excluding MNV VLP, resulted in significantly reduced viral loads following MNV challenge. Passive transfer of sera from mice monovalently vaccinated with MNV VLP to immunodeficient or immunocompetent mice protected against MNV infection; however, adoptive transfer of purified CD4(+) or CD8(+) cells did not influence viral loads in murine tissues. Together, these data suggest that humoral immunity induced by multivalent norovirus vaccines may protect against heterologous norovirus challenge.

A multi-valent vaccine approach that elicits broad immunity within an influenza subtype

Vaccines directed toward individual strains of highly variable viruses like influenza lose efficacy when the circulating viruses no longer resemble the vaccine isolate. Historically, inclusion of more than one isolate per subtype of influenza has been limited by the need to include large doses of antigen with typical protein-based vaccine approaches and by concerns that an immunodominant response to one antigen will limit the response to closely related antigens. Here we provide proof of principle demonstrating that a multi-valent vaccine directed against multiple influenza A virus hemagglutinins (HAs) can elicit broad, neutralizing immunity against multiple strains within a single influenza subtype (H3). We employed a DNA vaccine to direct immunity toward the HA component alone, and a live attenuated influenza virus (LAIV) to assess immunity against the whole virus. Delivery of either HA-DNA or LAIV yielded broad protective immunity across multiple antigenic clusters, including heterologous strains, that was similar to the combined immunity of each antigen assessed separately. Priming with HA-DNA followed by an LAIV boost strengthened and broadened the antibody response toward all three H3 HAs. This prime:boost multi-valent approach was thus able to elicit immunity against multiple strains within the H3 subtype without evidence of immune interference between closely related antigens. Although the trivalent vaccine described here is not a universal vaccine, since protection was limited to circulating viruses from about a two-decade period, these data suggest that full protection within a subtype is possible using this approach with multiple antigens from current and predicted future influenza strains.

An update of prophylactic human papillomavirus L1 virus-like particle vaccine clinical trial results

This review focuses on recent publications of clinical trials of two prophylactic human papillomavirus (HPV) vaccines: Gardasil (Merck & Co., Inc., Whitehouse Station, NJ USA), a quadrivalent vaccine containing L1 virus-like particles (VLPs) of types -6, 11, 16, and 18, and Cervarix (GlaxoSmithKline Biologicals, Rixensart, Belgium), a bivalent vaccine containing VLPs of types -16 and 18. In efficacy trials involving young women, both vaccines produced outstanding efficacy against primary and secondary endpoints associated with the vaccine type HPVs and were highly and consistently immunogenic. Both had excellent safety records and, as expected, the most frequent vaccine-related adverse were mild to moderate injection site sequelae. No evidence of waning protection was observed after four years for endpoints examined ranging from incident infection to cervical intraepithelial neoplasia grade 3 associated with the vaccine type HPVs. Gardasil was also highly efficacious at preventing vaginal/vulvar lesions and genital warts. However, neither vaccine demonstrated therapeutic efficacy against prevalent infections or lesions, regardless of the associated HPV type. Cervarix has shown limited cross-protection against infection with specific closely related types while preliminary results of limited cross-protection have been presented for Gardasil. As expected, more limited efficacy was noted for both vaccines when women with prevalent infection were included or endpoints associated with any HPV type were evaluated. Immunological bridging trials involving adolescent girls and boys were also recently published. For both vaccines, serum VLP antibody levels in girls were non-inferior to those generated in young women and antibody response to Gardasil was also non-inferior in boys. The results of these studies have led to the approval of Gardasil and Cervarix by national regulatory agencies in a number of countries.