Long-term efficacy of a recombinant hepatitis E vaccine in adults: 10-year results from a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Hepatitis E virus (HEV) is a frequently overlooked causative agent of acute hepatitis. Evaluating the long-term durability of hepatitis E vaccine efficacy holds crucial importance. METHODS: This study was an extension to a randomised, double-blind, placebo-controlled, phase-3 clinical trial of the hepatitis E vaccine conducted in Dontai County, Jiangsu, China. Participants were recruited from 11 townships in Dongtai County. In the initial trial, a total of 112 604 healthy adults aged 16-65 years were enrolled, stratified according to age and sex, and randomly assigned in a 1:1 ratio to receive three doses of hepatitis E vaccine or placebo intramuscularly at month 0, month 1, and month 6. A sensitive hepatitis E surveillance system including 205 clinical sentinels, covering the entire study region, was established and maintained for 10 years after vaccination. The primary outcome was the per-protocol efficacy of hepatitis E virus vaccine to prevent confirmed hepatitis E occurring at least 30 days after administration of the third dose. Throughout the study, the participants, site investigators, and laboratory staff remained blinded to the treatment assignments. This study is registered with ClinicalTrials.gov (NCT01014845). FINDINGS: During the 10-year study period from Aug 22, 2007, to Oct 31, 2017, 90 people with hepatitis E were identified; 13 in the vaccine group (0·2 per 10 000 person-years) and 77 in the placebo group (1·4 per 10 000 person-years), corresponding to a vaccine efficacy of 83·1% (95% CI 69·4-91·4) in the modified intention-to-treat analysis and 86·6% (73·0 to 94·1) in the per-protocol analysis. In the subsets of participants assessed for immunogenicity persistence, of those who were seronegative at baseline and received three doses of hepatitis E vaccine, 254 (87·3%) of 291 vaccinees in Qindong at the 8·5-year mark and 1270 (73·0%) of 1740 vaccinees in Anfeng at the 7·5-year mark maintained detectable concentrations of antibodies. INTERPRETATION: Immunisation with this hepatitis E vaccine offers durable protection against hepatitis E for up to 10 years, with vaccine-induced antibodies against HEV persisting for at least 8·5 years. FUNDING: National Natural Science Foundation of China, Fujian Provincial Natural Science Foundation, Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences, and the Fundamental Research Funds for the Central Universities.

Goats with low levels of AAV antibody may serve as candidates for large animal gene therapy.

AAV vector-mediated gene therapy has been proposed as a feasible strategy for several eye diseases. However, AAV antibodies in the serum prior to treatment hinder the transduction efficiency and thus the therapeutic effect. Therefore, it is necessary to evaluate AAV antibodies in the serum before gene therapy. As large animals, goats are more closely related to humans than rodents and more economically available than nonhuman primates. Here, we first evaluated the AAV2 antibody serum level in rhesus monkeys before AAV injection. Then, we optimized a cell-based neutralizing antibody assay for detecting AAV antibodies in the serum of Saanen goats and evaluated the consistency of the cell-based neutralizing antibody assay and ELISA for goat serum antibody evaluation. The cell-based neutralizing antibody assay showed that the percentage of macaques with low antibody levels was 42.86%; however, there were no macaques with low antibody levels when the serum was evaluated by ELISA. The proportion of goats with low antibody levels was 56.67% according to the neutralizing antibody assay and 33. 33% according to the ELISA, and McNemar's test showed that the results of the two assays were not significantly different (P = 0.754), but that their consistency is poor (Kappa = 0.286, P = 0.114). Moreover, longitudinal evaluation of serum antibodies before and after intravitreal injection of AAV2 in goats revealed that the level of AAV antibodies increased and transduction inhibition subsequently increased, as reported in humans, indicating that transduction inhibition should be taken into account at different stages of gene therapy. In summary, starting with an evaluation of monkey serum antibodies, we optimized a detection method of goat serum antibodies, providing an alternative large animal model for gene therapy, and our serum antibody measurement method may be applied to other large animals.

Long-term efficacy of a hepatitis E vaccine.

BACKGROUND: Hepatitis E virus (HEV) is a leading cause of acute hepatitis. The long-term efficacy of a hepatitis E vaccine needs to be determined. METHODS: In an initial efficacy study, we randomly assigned healthy adults 16 to 65 years of age to receive three doses of either a hepatitis E vaccine (vaccine group; 56,302 participants) or a hepatitis B vaccine (control group; 56,302 participants). The vaccines were administered at 0, 1, and 6 months, and the participants were followed for 19 months. In this extended follow-up study, the treatment assignments of all participants remained double-blinded, and follow-up assessments of efficacy, immunogenicity, and safety were continued for up to 4.5 years. RESULTS: During the 4.5-year study period, 60 cases of hepatitis E were identified; 7 cases were confirmed in the vaccine group (0.3 cases per 10,000 person-years), and 53 cases in the control group (2.1 cases per 10,000 person-years), representing a vaccine efficacy of 86.8% (95% confidence interval, 71 to 94) in the modified intention-to-treat analysis, rather than (95% confidence interval, 71 to 84) [corrected]. Of the participants who were assessed for immunogenicity and were seronegative at baseline, 87% of those who received three doses of the hepatitis E vaccine maintained antibodies against HEV for at least 4.5 years; HEV antibody titers developed in 9% in the control group. The rate of adverse events was similar in the two groups. CONCLUSIONS: Immunization with this hepatitis E vaccine induced antibodies against HEV and provided protection against hepatitis E for up to 4.5 years. (Funded by the Chinese Ministry of Science and Technology and others; ClinicalTrials.gov number, NCT01014845.).

Vitrectomy and ILM peeling in rhesus macaque: pitfalls and tips for success.

BACKGROUND: The non-human primate (NHP) model is ideal for pre-clinical testing of novel therapies for human retinal diseases due to its similarity to the human visual system. However, intra-ocular delivery of gene therapy or cell transplantation to the retina gets hampered by the sticky vitreous body and poorly permeable inner limiting membrane (ILM) in primates. Although vitrectomy and ILM peeling are commonly performed in patients, many pitfalls exist in carrying out these procedures in the rhesus macaque, which have not been reported previously. METHODS: We summarised common surgical pitfalls after performing vitrectomy and ILM peeling in four eyes of two rhesus macaques (one male and one female). We provided corresponding hands-on technical tips based on our surgical experience and literature search. Orbital CT scans were compared between adult rhesus macaques and humans. High-resolution surgical videos were recorded to demonstrate each critical surgical step. RESULTS: Due to size difference, poor post-operative compliance, and high-standard requirements of a controlled experiment, there were eleven common surgical pitfalls during vitrectomy and ILM peeling in rhesus macaque. Falling into these pitfalls may produce discomfort, add fatigue, cause surgical complications, or even lead to the exclusion of the NHP from an experimental group. CONCLUSION: Recognition and circumvention of these pitfalls during vitrectomy and ILM peeling in NHP are essential. By focusing on these surgical pitfalls, we can better carry out preclinical tests of novel therapies for retinal diseases in the NHP model.

Safety of hepatitis E vaccination for pregnancy: a post-hoc analysis of a randomized, double-blind, controlled phase 3 clinical trial.

Special attention has been paid to Hepatitis E (HE) prophylaxis for pregnant women due to poor prognosis of HE in this population. We conducted a post-hoc analysis based on the randomized, double-blind, HE vaccine (Hecolin)-controlled phase 3 clinical trial of human papillomavirus (HPV) vaccine (Cecolin) conducted in China. Eligible healthy women aged 18-45 years were randomly assigned to receive three doses of Cecolin or Hecolin and were followed up for 66 months. All the pregnancy-related events throughout the study period were closely followed up. The incidences of adverse events, pregnancy complications, and adverse pregnancy outcomes were analysed based on the vaccine group, maternal age, and interval between vaccination and pregnancy onset. During the study period, 1263 Hecolin receivers and 1260 Cecolin receivers reported 1684 and 1660 pregnancies, respectively. The participants in the two vaccine groups showed similar maternal and neonatal safety profiles, regardless of maternal age. Among the 140 women who were inadvertently vaccinated during pregnancy, the incidences of adverse reactions had no statistical difference between the two groups (31.8% vs 35.1%, p = 0.6782). The proximal exposure to HE vaccination was not associated with a significantly higher risk of abnormal foetal loss (OR 0.80, 95% CI 0.38-1.70) or neonatal abnormality (OR 2.46, 95% CI 0.74-8.18) than that to HPV vaccination, as did distal exposure. Significant difference was not noted between pregnancies with proximal and distal exposure to HE vaccination. Conclusively, HE vaccination during or shortly before pregnancy is not associated with increased risks for both the pregnant women and pregnancy outcomes.

Head-to-head immunogenicity comparison of an Escherichia coli-produced 9-valent human papillomavirus vaccine and Gardasil 9 in women aged 18-26 years in China: a randomised blinded clinical trial.

BACKGROUND: An Escherichia coli-produced human papillomavirus (HPV) 16 and 18 bivalent vaccine (Cecolin) was prequalified by WHO in 2021. This study aimed to compare the immunogenicity of the E coli-produced HPV 9-valent vaccine Cecolin 9 (against HPV 6, 11, 16, 18, 31, 33, 45, 52, and 58) with Gardasil 9. METHODS: This was a randomised, single-blind trial conducted in China. Healthy non-pregnant women aged 18-26 years, who were not breastfeeding and with no HPV vaccination history, were enrolled in the Ganyu Centre for Disease Control and Prevention (Lianyungang City, Jiangsu Province, China). Women were stratified by age (18-22 years and 23-26 years) and randomly assigned (1:1) using a permutated block size of eight to receive three doses of Cecolin 9 or Gardasil 9 at day 0, day 45, and month 6. All participants, as well as study personnel without access to the vaccines, were masked. Neutralising antibodies were measured by a triple-colour pseudovirion-based neutralisation assay. The primary outcomes, seroconversion rates and geometric mean concentrations (GMCs) at month 7, were analysed in the per-protocol set for immunogenicity (PPS-I). Non-inferiority was identified for the lower limit of the 95% CI of the GMC ratio (Cecolin 9 vs Gardasil 9) at a margin of 0·5 and a seroconversion rate difference (Cecolin 9-Gardasil 9) at a margin of -5%. This study was registered at ClinicalTrials.gov (NCT04782895) and is completed. FINDINGS: From March 14 to 18, 2021, a total of 553 potential participants were screened, of which 244 received at least one dose of Cecolin 9 and 243 received at least one dose of Gardasil 9. The seroconversion rates for all HPV types in both groups were 100% in the PPS-I, with the values of the lower limits of 95% CIs for seroconversion rate differences ranging between -1·8% and -1·7%. The GMC ratios of five types were higher than 1·0, with the highest ratio, for HPV 58, at 1·65 (95% CI 1·38-1·97), and those of four types were lower than 1·0, with the lowest ratio, for HPV 11, at 0·79 (0·68-0·93). The incidence of adverse reactions in both groups was similar (43% [104/244] vs 47% [115/243]). INTERPRETATION: Cecolin 9 induced non-inferior HPV type-specific immune responses compared with Gardasil 9 and is a potential candidate to accelerate the elimination of cervical cancer by allowing for global accessibility to 9-valent HPV vaccinations, especially in low-income and middle-income countries. FUNDING: National Natural Science Foundation, Fujian Provincial Natural Science Foundation, Xiamen Science and Technology Plan Project, Fundamental Research Funds for the Central Universities, CAMS Innovation Fund for Medical Sciences of China, and Xiamen Innovax.

Safety and immunogenicity of an Escherichia coli-produced 9-valent human papillomavirus L1 virus-like particle vaccine (types 6/11/16/18/31/33/45/52/58) in healthy adults: an open-label, dose-escalation phase 1 clinical trial.

Background: A safe and highly efficacious Escherichia coli (E. coli)-produced HPV 16/18 bivalent vaccine has been prequalified by the World Health Organization. Here, we conducted a single-center, open-label, dose-escalation phase 1 clinical trial to evaluate the safety and immunogenicity of the second-generation nonavalent HPV 6/11/16/18/31/33/45/52/58 vaccine. Method: Twenty-four eligible volunteers aged 18-45 years were enrolled in January 2019 in Dongtai, China and received 0.5 mL (135 µg) or 1.0 mL (270 µg) of the candidate vaccine with a 0/1/6-month dose-escalation schedule. Local and systemic adverse events (AEs) occurring within 30 days after each vaccination and serious adverse events (SAEs) occurring within 7 months were recorded. Blood samples from each participant were collected before and 2 days after the first and third vaccinations to determine changes in laboratory parameters. Serum IgG and neutralizing antibody (nAb) levels against each HPV type at month 7 were analyzed (ClinicalTrials.gov: NCT03813940). Findings: The incidences of total AEs in the 135 µg and 270 µg groups were 66.7% and 83.3%, respectively. All AEs were mild or moderate, and no SAEs were reported. No clinically significant changes were found in paired blood indices before or after any of the vaccinations. All the participants in the per-protocol set except for two who failed to seroconvert for HPV 11 or 58 in the 135 µg group seroconverted at month 7 for both IgG and nAbs. Interpretation: The candidate E. coli-produced 9vHPV vaccine has been preliminarily proven to be well tolerated and immunogenic, which encourages further studies in large cohorts with a wider age range. Funding: This study was supported by the National Natural Science Foundation of China, Fujian Provincial Natural Science Foundation, Fujian Province Health and Education Joint Research Program, Xiamen Science and Technology Plan Project, Fundamental Research Funds for the Central Universities, CAMS Innovation Fund for Medical Sciences of China, and Xiamen Innovax Biotechnology Co., Ltd.

Safety and immunogenicity of an Escherichia coli-produced bivalent human papillomavirus type 6/11 vaccine: A dose-escalation, randomized, double-blind, placebo-controlled phase 1 trial.

A dose-escalation, randomized, double-blind, placebo-controlled phase 1 clinical trial enrolled 145 eligible participants aged 18-55 years in March 2015 in Liuzhou, China. Stratified by age and sex, the participants were randomly assigned to receive either 30, 60, or 90 µg of the HPV-6/11 vaccine (n = 41/40/40) or the parallel placebo vaccine (n = 8/8/8) with a 0/1/6-month dose-escalation schedule. Participants were actively followed-up to record local and systemic AEs occurring within 30 days after each vaccination, and SAEs occurred in 7 months. Blood and urine samples of each participant were collected before and 2 days after the first and third vaccination to determine changes in routine blood, serum biochemical, and urine indexes. Serum HPV-6/11-specific IgG and neutralizing antibody levels at month 7 were analyzed. A total of 79 adverse events were reported, and no SAEs occurred. The incidences of total adverse reactions in the 30 µg, 60 µg, and 90 µg HPV vaccine groups and the control group were 31.7%, 50.0%, 42.5%, and 62.5%, respectively. All but one of the adverse reactions was mild or moderate with grade 1 or 2. No vaccine-related changes with clinical significance were found in paired blood and urine indexes before and after vaccinations. All the participants in the per-protocol set seroconverted at month 7 for both IgG and neutralizing antibodies. The candidate novel Escherichia-coli-produced bivalent HPV-6/11 vaccine has been preliminarily proven to be well tolerated and with robust immunogenicity in a phase 1 clinical study, supporting further trials with larger sample size. The study has been registered at ClinicalTrials.gov (NCT02405520).

Efficacy, safety, and immunogenicity of an Escherichia coli-produced Human Papillomavirus (16 and 18) L1 virus-like-particle vaccine: end-of-study analysis of a phase 3, double-blind, randomised, controlled trial.

BACKGROUND: This Escherichia coli-produced bivalent HPV 16 and 18 vaccine was well tolerated and effective against HPV 16 and 18 associated high-grade genital lesions and persistent infection in interim analysis of this phase 3 trial. We now report data on long-term efficacy and safety after 66 months of follow-up. METHODS: This phase 3, double-blind, randomised, controlled trial was done in five study sites in China. Eligible participants were women aged 18-45 years, with intact cervix and 1-4 lifetime sexual partners. Women who were pregnant or breastfeeding, had chronic disease or immunodeficiency, or had HPV vaccination history were excluded. Women were stratified by age (18-26 and 27-45 years) and randomly (1:1) allocated by software (block randomisation with 12 codes to a block) to receive three doses of the E coli-produced HPV 16 and 18 vaccine or hepatitis E vaccine (control) and followed-up for 66 months. The primary outcomes were high-grade genital lesions and persistent infection (longer than 6 months) associated with HPV 16 or 18 in the per-protocol susceptible population. This trial was registered with ClinicalTrials.gov, NCT01735006. FINDINGS: Between Nov 22, 2012, and April 1, 2013, 8827 women were assessed for eligibility. 1455 women were excluded, and 7372 women were enrolled and randomly assigned to receive the HPV vaccine (n=3689) or control (n=3683). Vaccine efficacy was 100·0% (95% CI 67·2-100·0) against high-grade genital lesions (0 [0%] of 3310 participants in the vaccine group and 13 [0·4%] of 3302 participants in the control group) and 97·3% (89·9-99·7) against persistent infection (2 [0·1%] of 3262 participants in the vaccine group and 73 [2·2%] of 3271 participants in the control group) in the per-protocol population. Serious adverse events occurred at a similar rate between vaccine (267 [7·2%] of 3691 participants) and control groups (290 [7·9%] of 3681); none were considered related to vaccination. INTERPRETATION: The E coli-produced HPV 16 and 18 vaccine was well tolerated and highly efficacious against HPV 16 and 18 associated high-grade genital lesions and persistent infection and would supplement the global HPV vaccine availability and accessibility for cervical cancer prevention. FUNDING: National Natural Science Foundation of China, National Key R&D Program of China, Fujian Provincial Project, Fundamental Funds for the Central Universities, Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences, and Xiamen Innovax.

Capsid destabilization and epitope alterations of human papillomavirus 18 in the presence of thimerosal.

Thimerosal has been widely used as a preservative in drug and vaccine products for decades. Due to the strong propensity to modify thiols in proteins, conformational changes could occur due to covalent bond formation between ethylmercury (a degradant of thimerosal) and thiols. Such a conformational change could lead to partial or even complete loss of desirable protein function. This study aims to investigate the effects of thimerosal on the capsid stability and antigenicity of recombinant human papillomavirus (HPV) 18 virus-like particles (VLPs). Dramatic destabilization of the recombinant viral capsid upon thimerosal treatment was observed. Such a negative effect on the thermal stability of VLPs preserved with thimerosal was shown to be dependent on the thimerosal concentration. Two highly neutralizing antibodies, 13H12 and 3C3, were found to be the most sensitive to thimerosal treatment. The kinetics of antigenicity loss, when monitored with 13H12 or 3C3 as probes, yielded two distinctly different sets of kinetic parameters, while the data from both monoclonal antibodies (mAbs) followed a biphasic exponential decay model. The potential effect of thimerosal on protein function, particularly for thiol-containing proteinaceous active components, needs to be comprehensively characterized during formulation development when a preservative is necessary.

Inflammation-related adverse reactions following vaccination potentially indicate a stronger immune response.

Concerns about vaccine safety are an important reason for vaccine hesitancy, however, limited information is available on whether common adverse reactions following vaccination affect the immune response. Data from three clinical trials of recombinant vaccines were used in this post hoc analysis to assess the correlation between inflammation-related solicited adverse reactions (ISARs, including local pain, redness, swelling or induration and systematic fever) and immune responses after vaccination. In the phase III trial of the bivalent HPV-16/18 vaccine (Cecolin®), the geometric mean concentrations (GMCs) for IgG anti-HPV-16 and -18 (P<0.001) were significantly higher in participants with any ISAR following vaccination than in those without an ISAR. Local pain, induration, swelling and systemic fever were significantly correlated with higher GMCs for IgG anti-HPV-16 and/or anti-HPV-18, respectively. Furthermore, the analyses of the immunogenicity bridging study of Cecolin® and the phase III trial of a hepatitis E vaccine yielded similar results. Based on these results, we built a scoring model to quantify the inflammation reactions and found that the high score of ISAR indicates the strong vaccine-induced antibody level. In conclusion, this study suggests inflammation-related adverse reactions following vaccination potentially indicate a stronger immune response.

Naturally acquired HPV antibodies against subsequent homotypic infection: A large-scale prospective cohort study.

BACKGROUND: Although recent studies have suggested that naturally acquired Human papillomavirus (HPV) antibodies are partly protective against subsequent homotypic infection, the extent of protection remains indecisive. Here, we evaluate the protective effect of neutralizing and IgG antibodies simultaneously. METHODS: In a cohort of 3634 women aged 18-45 years from the control arm of a phase III trial of the HPV-16/18 bivalent vaccine, participants were tested for neutralizing antibodies by pseudovirion-based neutralization assay (PBNA) and IgG antibodies by enzyme-linked immunosorbent assay (ELISA) at baseline. HPV-16/18 incident and persistent infections were identified using cervical specimens periodically collected during the 5·5 years of follow-up. The protective effects of HPV-16/18 neutralizing and IgG antibodies against homotypic infection were assessed using a Cox proportional hazard model. FINDINGS: For the persistent infection (PI) endpoints of HPV-16/18 lasting for over 6/12 months, a prevalence of type-specific neutralizing antibodies was highly protective (6-month PI: hazard ratio (HR) = 0·16, 95% confidence interval (CI): 0·04, 0·65; 12-month PI: HR = 0·23, 95% CI: 0·06, 0·94), whereas a prevalence of IgG antibodies was associated with minor and non-significant protection (6-month PI: HR = 0·66, 95% CI: 0·40, 1·09; 12-month PI: HR = 0·66, 95% CI: 0·36, 1·20). After increasing the cut-off value to the median IgG level, the risk of 6-month PI was significantly lower in seropositive vs seronegative women (HR = 0·38, 95% CI: 0·18, 0·83). INTERPRETATION: Naturally acquired antibodies are associated with a substantially reduced risk of subsequent homotypic infection. FUNDING: NSFC; The Fujian Province Health Education Joint Research Project; Xiamen Science and Technology Major Project; CIFMS; and Xiamen Innovax.

Comparing immunogenicity of the Escherichia coli-produced bivalent human papillomavirus vaccine in females of different ages.

BACKGROUND: The safety and efficacy of a recently licensed Escherichia coli (E. coli)-produced bivalent HPV vaccine have been shown. Specific antibody levels are important indicators to evaluate the efficacy of vaccination. Therefore, we compared the immunogenicity of this HPV 16/18 vaccine in females of different ages in this study. METHODS: Immunogenicity of the vaccine was analyzed in the per-protocol sets for immunogenicity (PPS-I) of a phase III trial and an immune-bridging trial. The serum samples were collected at month 0 and one month after the final dose (month 7) to assess the specific IgG antibody levels by ELISA. The seroconversion rates, geometric mean concentration (GMC), and geometric mean increase (GMI) were used to assess the immunogenicity of the test vaccine. The non-linear association of antibody levels with age was estimated via natural cubic splines and the Akaike information criterion was used to assess optimal model. RESULTS: By combining the PPS-I data from the two trials, nearly all of the females seroconverted for both HPV types. In the 3-dose group, the GMC of IgG to both HPV types decreased with increasing age, especially in adolescent girls and young women. For HPV-16 and -18, the declining trend slowed down in women older than 32 and 35 years old, respectively. The GMI ranged from 648 to 80 for HPV-16 and from 218 to 42 for HPV-18. In the 2-dose group, the specific antibodies for HPV-16 and -18 peaked in girls aged 10 years with GMIs of 401 and 98, respectively, and then decreased with age. CONCLUSIONS: The E. coli-produced bivalent HPV-16/18 vaccine induced specific antibody responses in females aged 9-45 years. The antibody levels were inversely associated with age, and the declining trends slowed down in women older than 32 or 35 years for HPV-16 and -18, respectively.

Demonstration of real-time and accelerated stability of hepatitis E vaccine with a combination of different physicochemical and immunochemical methods.

Hepatitis E, which is caused by infection with hepatitis E virus (HEV), is a global health problem in both developed and developing countries. An efficacious hepatitis E vaccine was licensed (by China) in 2011 with a trade name of Hecolin®. The antigen contained in this vaccine is a truncated version of the sole capsid protein encoded by open reading frame 2, which is designated p239. In this study, the real-time and real-condition stability and accelerated stability of five lots of hepatitis E vaccine products at the end of the designated shelf life, were assessed by a well-established quality analysis platform. The protein integrity of p239 that was recovered from the vaccine lots was demonstrated using CE-SDS, LC-MS and MALDI-TOF MS. The particle characteristics of the recovered vaccine antigen were assessed by TEM and HPSEC. The immunogenicity of hepatitis E vaccines was assessed by a mouse potency assay, which is part of product release and stability testing. Several methods were employed to assess the antigenicity of vaccines with or without adjuvant dissolution. Specifically, the well-established methods of sandwich ELISA and surface plasma resonance (SPR)-based BIAcore were used with unique murine monoclonal antibodies. Most interesting, two 'dissolution-free' immunoassays were also used for in situ antigenicity assessment of the vaccines. In addition to the confirmation of vaccine stability at the end of expiry dating, i.e., after storage in recommended conditions (2-8 °C) for 36 months, the mouse potency assay and sandwich ELISA were used to assess the accelerated stability of prefilled syringes to demonstrate the feasibility of out-of-cold-chain storage. In summary, molecular and functional characterization confirmed the shelf life stability of the vaccine at the end of expiry dating and the feasibility of transporting the hepatitis E vaccine for a given period of time out of cold chains.

Immunogenicity of an Escherichia coli-produced bivalent human papillomavirus vaccine under different vaccination intervals.

A new Escherichia coli-produced human papillomavirus (HPV)-16/18 vaccine has been shown to be safe and highly efficacious and was recently licensed in China. As a post hoc analysis of the phase III trial, this study aimed to assess the impact of vaccination time deviations on the specific antibody response and guide the better usage of this vaccine in the real world. A total of 3689 healthy women aged 18-45 years old were randomly assigned to receive the bivalent HPV-16/18 vaccine according to a 0-, 1- and 6-month schedule with a wide vaccination interval. The first vaccination interval between the 1st and 2nd doses (the 1st interval) was divided into three groups: 28-40 d, 41-50 d and 51-60 d. The second vaccination interval between the 2nd and 3rd doses (the 2nd interval) was divided into three groups: 103-139 d, 140-160 d and 161-198 d. The reverse cumulative curves for the IgG of the three groups with different 1st vaccination intervals or with different 2nd vaccination intervals at month 7 almost overlapped for both HPV-16 and HPV-18. Compared with the standard vaccination schedule (a 1st interval of 28-40 d and a 2nd interval of 140-160 d) subgroup, all the subgroups had GMC ratios greater than 0.83, with the lower limit of 95% CIs higher than 0.64. In conclusion, a slight deviation in the vaccination time of the 2nd and 3rd doses has only a minor, insignificant impact on the immune response induced by the Escherichia coli-produced HPV-16/18 vaccine.

Lot-to-lot consistency study of an Escherichia coli-produced bivalent human papillomavirus vaccine in adult women: a randomized trial.

An Escherichia. coli-produced HPV-16/18 bivalent vaccine has been proved to be well-tolerated and highly efficacious against diseases associated with vaccine HPV types. As a part of the multi-center, randomized, double-blind phase III clinical trial, this lot-to-lot consistency study aimed to assess the safety and immunogenicity consistency of this novel HPV vaccine, which is also one of the objectives of the phase III trial. A total of 3689 healthy women aged 18-45 years were enrolled and randomly assigned 1:1:1 to three lots of the HPV vaccine groups. The primary outcomes were the IgG antibody level at 1 month after the last dose (month 7). In the immunogenicity per-protocol set (PPS), almost all of the participants seroconverted at month 7 and remained seropositive at month 42. For each paired comparison of the three lot groups, the two-sides of 90% CIs of GMC ratios for both IgG and neutralizing antibodies for HPV-16 and HPV-18 at month 7 were within the equivalence interval [0.5, 2]. Lot consistency was also demonstrated at month 42. The majority of recorded solicited reactions were mild or moderate. The incidences of solicited reactions of Lot 2 and Lot 3 were slightly higher than Lot 1. However, the incidences of solicited reactions of ≥ grade 3 and solicited reactions by symptoms were all similar among the three lot groups. None of the SAEs was considered related to vaccination by the investigator. In conclusion, this study demonstrates lot-to-lot consistency of the 3 consecutive lots of the E. coli-produced HPV-16/18 bivalent vaccine.

Immunogenicity noninferiority study of 2 doses and 3 doses of an Escherichia coli-produced HPV bivalent vaccine in girls vs. 3 doses in young women.

A new HPV-16/18 bivalent vaccine expressed by the Escherichia coli has been proven to be efficacious in adult women. A randomized, immunogenicity noninferiority study of this candidate vaccine was conducted in December 2015 in China. Girls aged 9-14 years were randomized to receive 2 doses at months 0 and 6 (n=301) or 3 doses at months 0, 1 and 6 (n=304). Girls aged 15-17 years (n=149) and women aged 18-26 years (n=225) received 3 doses. The objectives included noninferiority analysis of the IgG geometric mean concentration (GMC) ratio (95% CI, lower bound>0.5) to HPV-16 and HPV-18 at month 7 in girls compared with women. In the per-protocol set, the GMC ratio of IgG was noninferior for girls aged 9-17 years receiving 3 doses compared with women (1.76 (95% CI, 1.56, 1.99) for HPV-16 and 1.93 (95% CI, 1.69, 2.21) for HPV-18) and noninferior for girls aged 9-14 years receiving 2 doses compared with women (1.45 (95% CI, 1.25, 1.62) for HPV-16 and 1.17 (95% CI, 1.02, 1.33) for HPV-18). Noninferiority was also demonstrated for neutralizing antibodies. The immunogenicity of the HPV vaccine in girls receiving 3 or 2 doses was noninferior compared with that in young adult women.

Efficacy, Safety, and Immunogenicity of an Escherichia coli-Produced Bivalent Human Papillomavirus Vaccine: An Interim Analysis of a Randomized Clinical Trial.

BACKGROUND: The high cost and insufficient supply of human papillomavirus (HPV) vaccines have slowed the pace of controlling cervical cancer. A phase III clinical trial was conducted to evaluate the efficacy, safety, and immunogenicity of a novel Escherichia coli-produced bivalent HPV-16/18 vaccine. METHODS: A multicenter, randomized, double-blind trial started on November 22, 2012 in China. In total, 7372 eligible women aged 18-45 years were age-stratified and randomly assigned to receive three doses of the test or control (hepatitis E) vaccine at months 0, 1, and 6. Co-primary endpoints included high-grade genital lesions and persistent infection (over 6 months) associated with HPV-16/18. The primary analysis was performed on a per-protocol susceptible population of individuals who were negative for relevant HPV type-specific neutralizing antibodies (at day 0) and DNA (at day 0 through month 7) and who received three doses of the vaccine. This report presents data from a prespecified interim analysis used for regulatory submission. RESULTS: In the per-protocol cohort, the efficacies against high-grade genital lesions and persistent infection were 100.0% (95% confidence interval = 55.6% to 100.0%, 0 of 3306 in the vaccine group vs 10 of 3296 in the control group) and 97.8% (95% confidence interval = 87.1% to 99.9%, 1 of 3240 vs 45 of 3246), respectively. The side effects were mild. No vaccine-related serious adverse events were noted. Robust antibody responses for both types were induced and persisted for at least 42 months. CONCLUSIONS: The E coli-produced HPV-16/18 vaccine is well tolerated and highly efficacious against HPV-16/18-associated high-grade genital lesions and persistent infection in women.

[Expression, purification and immunogenicity of human papillomavirus type 11 virus-like particles from Escherichia coli].

OBJECTIVE: To produce human papillomavirus type 11 virus-like particles (HPV11 VLPs) from Escherichia coli and to investigate its immunogenicity and type cross neutralization nature. METHODS: We expressed the major capsid protein of HPV11 (HPV11-L1) in Escherichia coli ER2566 in non fusion fashion and purified by amino sulfate precipitation, ion-exchange chromatography and hydrophobic interaction chromatography, sequentially. Then we removed the reductant DTT to have the purified HPV11-L1 self-assemble into VLPs in vitro. We investigated the morphology of these VLPs with dynamic light scattering and transmission electron microscopy. We assayed the immunogenicity of the resultant HPV11 VLPs by vaccinations on mice and evaluated by HPV6/11/16/18 pseudovirion neutralization cell models. RESULTS: We expressed HPV11 L1 in Escherichia coli with two forms, soluble and inclusion body. The soluble HPV11 L1 with over 95% purity can self assemble to VLPs in high efficiency. Morphologically, these VLPs were globular, homogeneous and with a diameter of - 50 nm, which is quite similar with native HPV11 virions. The half effective dosage (ED50) of HPV11 VLPs is 0.031 microg, and the maximum titer of neutralizing antibody elicited is averaged to 10(6). The cross neutralization activity (against HPV6/16/18) of the anti-HPV11 serum was found to have exact correlation to the inter-type homology in amino acid alignment. CONCLUSION: We can provide HPV11 VLPs with highly immunogenicity from prokaryote expression system, which may pave a new way for research and development of prophylactic vaccine for HPV11.

Simultaneous in situ visualization and quantitation of dual antigens adsorbed on adjuvants using high content analysis.

Aim: Traditional antigenicity assay requires antigen recovery from the particulate adjuvants prior to analysis. An in situ method was developed for interrogating vaccine antigens with monoclonal antibodies while being adsorbed on adjuvants. Materials & methods: The fluorescence imaging-based high content analysis was used to visualize the antigen distribution on adjuvant agglomerates and to analyze the antigenicity for adsorbed antigens. Results: Simultaneous visualization and quantitation were achieved for dual antigens in a bivalent human papillomavirus vaccine with uniquely labeled antibodies. Good agreement was observed between the in situ multiplexed assays with well-established sandwich enzyme-linked immunosorbent assays. Conclusion: The streamlined procedures and the amenability for multiplexing make the in situ antigenicity analysis a favorable choice for in vitro functional assessment of bionanoparticles as vaccine antigens.