Efficacy of the AS04-adjuvanted HPV-16/18 vaccine in young Chinese women with oncogenic HPV infection at baseline: post-hoc analysis of a randomized controlled trial

How has post-implementation surveillance of high-coverage vaccination with HPV16/18-AS04 vaccine in England added to evidence about its cross-protective effects?

BACKGROUND

Bivalent human papillomavirus HPV16/18-AS04 vaccine (Cervarix, GSK) offers direct protection against HPV16/18. Results from randomised controlled trials showed cross protective effects and suggested that declines in some closely related HPV types could be expected in a population with high vaccination coverage.

AIM

To evaluate the evidence for cross-protection afforded by HPV16/18-AS04 from post-implementation surveillance in England, and how this complements clinical trial data and post-implementation observations in other countries.

METHODS

Evidence of cross-protection in young women offered vaccination with HPV16/18-AS04 was gathered from HPV surveillance in England. Data from clinical trials and other post-implementation studies were reviewed.

RESULTS

Surveillance using anonymised residual specimens in England found declines of 52.3%, 67.4% and 33.3% against grouped HPV-31/33/45 in 16-18, 19-21, and 22-24 year olds, respectively. Additionally, type-specific analysis found that the prevalence of HPV31 declined to below 1% across all age groups. Cross-protection has been monitored and maintained for over 10 years since the introduction of the vaccination programme. Cross-protection against HPV6/11 was not found in English surveillance outcomes.

CONCLUSION

Surveillance of type-specific infections in vaccine-eligible populations in England has generated clear evidence of cross-protective effects from HPV16/18-AS04 vaccination against high-risk HPV 31/33/45 infections, consistent with other post-implementation observations and confirming and in some ways exceeding expectations from clinical trials.

Current status and future directions for the development of human papillomavirus vaccines

The development of human papillomavirus (HPV) vaccines has made substantive progress, as represented by the approval of five prophylactic vaccines since 2006. Generally, the deployment of prophylactic HPV vaccines is effective in preventing newly acquired infections and incidences of HPV-related malignancies. However, there is still a long way to go regarding the prevention of all HPV infections and the eradication of established HPV infections, as well as the subsequent progression to cancer. Optimizing prophylactic HPV vaccines by incorporating L1 proteins from more HPV subtypes, exploring adjuvants that reinforce cellular immune responses to eradicate HPV-infected cells, and developing therapeutic HPV vaccines used either alone or in combination with other cancer therapeutic modalities might bring about a new era getting closer to the vision to get rid of HPV infection and related diseases. Herein, we summarize strategies for the development of HPV vaccines, both prophylactic and therapeutic, with an emphasis on the selection of antigens and adjuvants, as well as implications for vaccine efficacy based on preclinical studies and clinical trials. Additionally, we outline current cutting-edge insights on formulation strategies, dosing schedules, and age expansion among HPV vaccine recipients, which might play important roles in addressing barriers to vaccine uptake, such as vaccine hesitancy and vaccine availability.

Efficacy and immunogenicity of AS04-HPV-16/18 vaccine in females with existing cervical HR-HPV infection at first vaccination: A pooled analysis of four large clinical trials worldwide

Females with existing high-risk HPV (HR-HPV) infections remain at risk of subsequent multiple or recurrent infections, on which benefit from HPV vaccines was under-reported. We pooled individual-level data from four large-scale, RCTs of AS04-HPV-16/18 vaccine to evaluate efficacy and immunogenicity in females DNA-positive to any HR-HPV types at first vaccination. Females receiving the AS04-HPV-16/18 vaccine in the original RCTs constituted the vaccine group in the present study, while those unvaccinated served as the control group. Vaccine efficacy (VE) against new infections and associated cervical intraepithelial neoplasia (CIN) 2+ in females DNA-negative to the considered HR-HPV type but positive to any other HR-HPV types, VE against reinfections in females DNA-positive to the considered HR-HPV type but cleared naturally during later follow-up, and levels of anti-HPV-16/18 IgG were assessed. Our final analyses included 5137 females (vaccine group = 2532, control group = 2605). The median follow-up time was 47.88 months (IQR: 45.72-50.04). For the prevention of precancerous lesions related to the non-infected HR-HPV types at baseline, VE against HPV-16/18 related CIN 2+ was 82.70% (95% CI: 63.70-93.00%). For the prevention of reinfections related to the infected HR-HPV types following natural clearance, VE against HPV-16/18 12MPI was non-significant (p > .05), albeit robust immunity persisted for at least 48 months. Females with existing HR-HPV infections at first vaccination still benefit from vaccination in preventing precancers related to the non-infected types at baseline. VE against reinfections related to the infected types following natural clearance remains to be further investigated.

Immunogenicity, efficacy, and safety of human papillomavirus vaccine: Data from China

The incidence rate and mortality rate of cervical cancer have steadily increased in young women in China. Therefore, it is critical to improve HPV vaccination rates, particularly for the younger population. There are currently five types of prophylactic vaccines in China: bivalent HPV vaccine (AS04-HPV-16/18), quadrivalent HPV vaccine, 9-valent HPV vaccine, homemade Escherichia coli-produced HPV bivalent vaccine, and Pichia pastoris produced HPV bivalent vaccine. All these five HPV vaccines have completed relevant clinical trials in China, and have been proven to be generally well-tolerated and immunogenic, efficacious against persistent HPV-related infections and genital precancerous lesions (data for 9-valent HPV vaccine is absent), and have demonstrated acceptable safety profiles, as previously shown in global studies. Given that the HPV vaccination rate in China is still very low, additional HPV vaccine coverage is needed to reduce the incidence and mortality rates of cervical cancer.

Update on the Epidemiological Features and Clinical Implications of Human Papillomavirus Infection (HPV) and Human Immunodeficiency Virus (HIV) Coinfection

Human papillomavirus (HPV) infection is the most common sexually transmitted infection (STI) worldwide. Although most HPV infections will spontaneously resolve, a considerable proportion of them will persist, increasing the risk of anogenital dysplasia, especially within certain populations, such as patients infected with human immunodeficiency virus (HIV). Furthermore, high-risk oncogenic HPV types (HR-HPV) are the main cause of cervix and other anogenital cancers, such as cancer of the vagina, vulva, penis, or anus. HIV and HPV coinfection is common among people living with HIV (PLWH) but disproportionally affects men who have sex with men (MSM) for whom the rate of persistent HPV infection and reinfection is noteworthy. The molecular interactions between HIV and HPV, as well as the interplay between both viruses and the immune system, are increasingly being understood. The immune dysfunction induced by HIV infection impairs the rate of HPV clearance and increases its oncogenic risk. Despite the availability of effective antiretroviral therapy (ART), the incidence of several HPV-related cancers is higher in PLWH, and the burden of persistent HPV-related disease has become a significant concern in an aging HIV population. Several public health strategies have been developed to reduce the transmission of HIV and HPV and mitigate the consequences of this type of coinfection. Universal HPV vaccination is the most effective preventive tool to reduce the incidence of HPV disease. In addition, screening programs for HPV-related cervical and vulvovaginal diseases in women are well-recognized strategies to prevent cervical cancer. Similarly, anal dysplasia screening programs are being implemented worldwide for the prevention of anal cancer among PLWH. Herein, the main epidemiological features and clinical implications of HIV and HPV coinfection are reviewed, focusing mainly on the relationship between HIV immune status and HPV-related diseases and the current strategies used to reduce the burden of HPV-related disease.