Evaluation of the HPV 18 antibody response in Gardasil®vaccinees after 48 mo using a pseudovirion neutralization assay

Safety and immunogenicity of a pichia pastoris-expressed bivalent human papillomavirus (types 16 and 18) L1 virus-like particle vaccine in healthy Chinese women aged 9-45 years: A randomized, double-blind, placebo-controlled phase 1 clinical trial

BACKGROUND

We evaluated the safety and immunogenicity of high and low doses of a novel pichia pastoris-expressed bivalent (types 16 and 18) human papillomavirus (HPV) virus-like particle vaccine.

METHODS

In this randomized, double-blind, placebo-controlled phase 1 trial, we enrolled 160 healthy females aged 9-45 years in Guangxi, China who were randomized (1:1:2) to receive either low (0.5 mL) or high (1.0 mL) dosages of bivalent HPV vaccine, or placebo (aluminum adjuvant) in a 0, 2, 6 months schedule. Adverse events and other significant conditions that occurred within 30 days after each vaccination were recorded throughout the trial. Sera were collected at days 0, 60, 180 and 210 to measure anti-HPV 16/18 neutralizing antibodies.

RESULTS

A total of 160 participants received at least one dose of the HPV vaccine and 152 completed the three dose vaccination series. Reporting rates of adverse events in placebo, low dose (0.5 mL) and high dose (1.0 mL) groups were 47.5 %, 55.0 % and 55.0 %, respectively. No serious adverse events occurred during this trial. 100 % of the participants who received three doses of the HPV vaccine produced neutralizing antibodies against HPV 16/18 vaccine. For HPV 16 and HPV 18, the geometric mean titers (GMTs) were similar between the low dose group (GMT_{HPV 16} = 10816 [95 % CI: 7824-14953]), GMT_{HPV 18} = 3966 [95 % CI: 2693-5841]) and high dose group (GMT _{HPV 16} = 14482 [95 % CI: 10848-19333], GMT _{HPV 18} = 3428 [95 % CI: 2533-4639]).

CONCLUSION

The pichia pastoris-expressed bivalent HPV vaccine was safe and immunogenic in Chinese females aged 9-45 years. The low dosage (0.5 mL) was selected for further immunogenicity and efficacy study.

AIDS Malignancy Consortium 054: Safety and Immunogenicity of the Quadrivalent Vaccine in Indian Women Living With HIV

BACKGROUND

Human papillomavirus (HPV)-associated cervical cancer is a leading cause of death among Indian women. Indian women living with HIV (WLWH) may be at especially high risk. The quadrivalent HPV (qHPV) vaccine is effective in prevention of initial infection with HPV-6/11/16/18 in HIV-negative women. Little is known about previous exposure to HPV-6/11/16/18, safety, and immunogenicity of qHPV in Indian WLWH.

METHODOLOGY

One hundred fifty WLWH with different CD4 levels and HIV viral load (VL) were vaccinated at 0/2/6 months at CART-CRS-IDMC, Chennai, India. Serology was performed at weeks 0, 28, and 52 for HPV-6/11/16/18 using a competitive Luminex immunoassay and for HPV-16/18 using a pseudovirion-based neutralization assay.

RESULTS

Mean age was 30.8 years (range, 19-44 years). 71/87/73/81% of women were naive (sero-negative and DNA-negative) to HPV-6/11/16/18 at baseline, respectively. Among per-protocol women naive to HPV-6/11/16/18 at baseline, 100/99/99/90%, respectively, seroconverted at week 28 and 95/96/98/71% were sero-positive at week 52, respectively. Pseudovirion-based neutralization assay identified more seroconversion to HPV-18 than competitive Luminex immunoassay. There were no significant differences in the proportion seroconverting by baseline or nadir CD4 or HIV VL; however, there was a trend for increased proportion seroconverting to HPV-18 among women with higher baseline CD4 level (P = 0.052). There were no qHPV-related serious adverse events and no change in CD4 level or HIV VL among women on ART.

CONCLUSIONS

qHPV vaccine was safe and immunogenic in Indian WLWH. A high proportion were naive to HPV-6/11/16/18 and may benefit from vaccination although many were married and several years post-initiation of sexual activity.

Controlled Hybrid-Assembly of HPV16/18 L1 Bi VLPs in Vitro

Based on the helix4-exchanged HPV16 L1 and HPV18 L1, HPV16 L1 Bi and HPV18 L1 Bi, we have successfully realized the controlled hybrid-assembly of HPV16/18 L1 Bi VLPs (bihybrid-VLPs) in vitro. The bihybrid-VLPs were further confirmed by fluorescence resonance energy transfer (FRET) and complex-immunoprecipitation (Co-IP) assays. The ratio of 16 L1 Bi and 18 L1 Bi in bihybrid-VLPs was verified to be 3:5 based on a modified magnetic Co-IP procedure, when mixing 1 equiv pentamer in assembly buffer solution, but it changed with conditions. In addition, the bihybrid-VLPs showed identical thermal stability as that of normal VLPs, suggesting high potential in practical applications. The present study is significant because it modified one of the vital steps of virus life cycle at the stage of virus assembly, supplying a new approach not only to deepen structural insights but also a possibility to prepare stable, low-cost, bivalent antivirus vaccine. Furthermore, the controlled hybrid-assembly of bihybrid-VLPs in vitro provides suggestions for the design of effective multivalent hybrid-VLPs, being a potential to develop broad-spectrum vaccines for the prevention of infection with multiple types of HPV.

Human papillomavirus vaccination in HIV-infected women: need for increased coverage

Human immunodeficiency virus (HIV)-infected women carry a significant burden on human papillomavirus (HPV) infection and associated diseases. As HIV-infected individuals are living longer, the prevalence of HPV infection is rising and HPV-associated cytological abnormalities remain high despite successful treatments of HIV infection. Several HPV vaccines are currently available and recommended for adolescents and adults up to age 26. The vaccines are safe, immunogenic and effective in preventing diseases due to HPV types included in the vaccines, particularly among persons without prior HPV exposure. This review summarizes available data on the use of the HPV vaccines among HIV-infected women. The immunogenicity and safety of the vaccines are highlighted and in particular, barriers to vaccination among HIV-infected women are discussed.

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.

Measurement of neutralizing serum antibodies of patients vaccinated with human papillomavirus L1 or L2-based immunogens using furin-cleaved HPV Pseudovirions

Antibodies specific for neutralizing epitopes in either Human papillomavirus (HPV) capsid protein L1 or L2 can mediate protection from viral challenge and thus their accurate and sensitive measurement at high throughput is likely informative for monitoring response to prophylactic vaccination. Here we compare measurement of L1 and L2-specific neutralizing antibodies in human sera using the standard Pseudovirion-Based Neutralization Assay (L1-PBNA) with the newer Furin-Cleaved Pseudovirion-Based Neutralization Assay (FC-PBNA), a modification of the L1-PBNA intended to improve sensitivity towards L2-specific neutralizing antibodies without compromising assay of L1-specific responses. For detection of L1-specific neutralizing antibodies in human sera, the FC- PBNA and L1-PBNA assays showed similar sensitivity and a high level of correlation using WHO standard sera (n = 2), and sera from patients vaccinated with Gardasil (n = 30) or an experimental human papillomavirus type 16 (HPV16) L1 VLP vaccine (n = 70). The detection of L1-specific cross-neutralizing antibodies in these sera using pseudovirions of types phylogenetically-related to those targeted by the L1 virus-like particle (VLP) vaccines was also consistent between the two assays. However, for sera from patients (n = 17) vaccinated with an L2-based immunogen (TA-CIN), the FC-PBNA was more sensitive than the L1-PBNA in detecting L2-specific neutralizing antibodies. Further, the neutralizing antibody titers measured with the FC-PBNA correlated with those determined with the L2-PBNA, another modification of the L1-PBNA that spacio-temporally separates primary and secondary receptor engagement, as well as the protective titers measured using passive transfer studies in the murine genital-challenge model. In sum, the FC-PBNA provided sensitive measurement for both L1 VLP and L2-specific neutralizing antibody in human sera. Vaccination with TA-CIN elicits weak cross-protective antibody in a subset of patients, suggesting the need for an adjuvant.

Immunogenicity and safety of the quadrivalent human papillomavirus vaccine in HIV-1-infected women

BACKGROUND

Women infected with human immunodeficiency virus (HIV) are disproportionately affected by human papillomavirus (HPV)-related anogenital disease, particularly with increased immunosuppression. AIDS Clinical Trials Group protocol A5240 was a trial of 319 HIV-infected women in the United States, Brazil, and South Africa to determine immunogenicity and safety of the quadrivalent HPV vaccine in 3 strata based on screening CD4 count: >350 (stratum A), 201-350 (stratum B), and ≤200 cells/µL (stratum C).

METHODS

Safety and serostatus of HPV types 6, 11, 16, and 18 were examined. HPV serological testing was performed using competitive Luminex immunoassay (HPV-4 cLIA). HPV type-specific seroconversion analysis was done for participants who were seronegative for the given type at baseline.

RESULTS

Median age of patients was 36 years; 11% were white, 56% black, and 31% Hispanic. Median CD4 count was 310 cells/µL, and 40% had undetectable HIV-1 load. No safety issues were identified. Seroconversion proportions among women at week 28 for HPV types 6, 11,16, and 18 were 96%, 98%, 99%, and 91%, respectively, for stratum A; 100%, 98%, 98%, and 85%, respectively, for stratum B, and 84%, 92%, 93%, and 75%, respectively, for stratum C.

CONCLUSIONS

The quadrivalent HPV vaccine targeted at types 6, 11, 16, and 18 was safe and immunogenic in HIV-infected women aged 13-45 years. Women with HIV RNA load >10 000 copies/mL and/or CD4 count <200 cells/µL had lower rates of seroconversion rates. Clinical Trials Registration. NCT00604175.

Virus-like particle-based human vaccines: quality assessment based on structural and functional properties

Human vaccines against three viruses use recombinant virus-like particles (VLPs) as the antigen: hepatitis B virus, human papillomavirus, and hepatitis E virus. VLPs are excellent prophylactic vaccine antigens because they are self-assembling bionanoparticles (20 to 60 nm in diameter) that expose multiple epitopes on their surface and faithfully mimic the native virions. Here we summarize the long journey of these vaccines from bench to patients. The physical properties and structural features of each recombinant VLP vaccine are described. With the recent licensure of Hecolin against hepatitis E virus adding a third disease indication to prophylactic VLP-based vaccines, we review how the crucial quality attributes of VLP-based human vaccines against all three disease indications were assessed, controlled, and improved during bioprocessing through an array of structural and functional analyses.

Assessment of HPV 16 and HPV 18 antibody responses by pseudovirus neutralization, Merck cLIA and Merck total IgG LIA immunoassays in a reduced dosage quadrivalent HPV vaccine trial

We assessed HPV 16 and 18 antibody responses of female subjects enrolled in a 2- vs. 3-dose quadrivalent HPV (Q-HPV) vaccine trial (ClinicalTrials.gov NCT00501137) using the Merck competitive Luminex (cLIA) and total IgG Luminex (TIgG) immunoassays, and a pseudovirus neutralizing antibody (PsV NAb) assay. Subjects were enrolled in one of three groups: (1) 9-13yr, 2 doses of Q-HPV at 0, 6 months (n=259); (2) 9-13yr, 3 doses at 0, 2, 6 months (n=260); and (3) 16-26yr, 3 doses at 0, 2, 6 months (n=305). Sera were collected from all subjects at baseline, months 7 and 24, and from half the subjects at months 18 and 36. High correlation was observed between all three assays. At month 36, HPV 16 antibodies remained detectable in all subjects by all assays, whereas 86.4%, 99.6% and 100% of subjects respectively were HPV 18 cLIA, TIgG and PsV NAb (partial neutralization endpoint) seropositive. The proportion seropositive for HPV 18 by cLIA at 36 months was not significantly different for 2-dose girls vs. 3-dose adults (85.9% vs. 79.4%; p=0.51), whereas the proportion for 3-dose girls was significantly higher than for 3-dose adults (95.3% vs. 79.4%; p<0.01). The HPV 18 seropositive proportions by the TIgG and PsV NAb (partial neutralization endpoint) assays were the same for all subjects. High baseline HPV 16 and HPV 18 seropositivity was observed for the TIgG assay and it is unclear if all the detected TIgG antibodies are type-specific and/or neutralizing. For the PsV NAb assay, 90% and partial neutralization geometric mean titres were consistently 2-8-fold higher than for 100% neutralization, which enabled detection of HPV 18 NAb in subjects who lost detectable cLIA antibodies over time. We conclude that the PsV NAb assay is more sensitive than the cLIA, and likely more specific than the TIgG assay.

Clinical trials of human papillomavirus vaccines and beyond

Human papillomavirus (HPV) is the most common sexually transmitted infectious agent; its 14 oncogenic types are causally associated with 5-10% of all cancers. The major structural HPV protein self-assembles into immunogenic virus-like particles. Two licensed HPV vaccines--the bivalent vaccine comprising HPV types 16 and 18, and the quadrivalent vaccine comprising HPV types 6, 11, 16 and 18--have proven to be safe and efficacious against 6-month-persistent cervical infections of HPV16 and HPV18 and associated precancerous lesions, and both have efficacies of 90-100%. Among baseline HPV-negative adolescent females, vaccine efficacies against the immediate precursor of cervical cancer (intraepithelial neoplasia grade 3) irrespective of HPV type are 93.2% and 43.0% for the bivalent and quadrivalent vaccines, respectively. The quadrivalent vaccine is efficacious (>75% vaccine efficacy) against any of the more-severe precursors of vulval, vaginal and anal cancers. A strong increase in vaccine efficacy with increasing severity of the precancerous lesion is explained by accumulation of the most-oncogenic HPV types 16 and 18 in these lesions. Therefore, prophylactic HPV vaccination will exceed the best results from screening for cancer. With the extremely efficacious prophylactic HPV vaccines, the focus of organized intervention (vaccination and screening) programmes should, however, shift from reducing the HPV disease burden to controlling the prevalence of oncogenic HPV (and nononcogenic HPV) types. Eradication of the major oncogenic HPV types should be pursued.

Efficacy of quadrivalent human papillomavirus (types 6, 11, 16 and 18) vaccine (GARDASIL) in Japanese women aged 18-26 years

A randomized double-blind placebo-controlled phase II trial was conducted to evaluate the efficacy of a prophylactic quadrivalent vaccine targeting the human papillomavirus (HPV) types most frequently associated with cervical cancer (types 16/18) and genital warts (types 6/11) in Japanese women aged 18-26 years. Participants were randomly assigned to either quadrivalent HPV (types 6/11/16/18) L1 virus-like particle vaccine (GARDASIL) (n = 509) or placebo (n = 512). Participants underwent regular gynecological examinations, cervicovaginal sampling for HPV DNA, testing for serum neutralizing antibodies to HPV and Papanicolau testing. The primary end-point was the combined incidence of persistent infection with HPV types 6, 11, 16 or 18 and cervical or external genital disease (i.e. cervical intraepithelial neoplasia, cervical cancer or external genital lesions related to HPV 6, 11, 16 or 18. Primary analyses were done per protocol. Combined incidence of persistent infection or disease with HPV 6, 11, 16 or 18 fell by 87.6% (95% confidence interval [CI], 59.2-97.6; P < 0.001), with HPV 6 or 11 by 73.1% (95% CI, -1.1-97.3; P = 0.0756) and with HPV 16 or 18 by 94.5% (95% CI, 65.2-99.9; P < 0.001) in those assigned vaccine compared with those assigned placebo. The median duration of follow up after month 7 in subjects was 23 months. In addition, the vaccine was well tolerated in Japanese women aged 18-26 years. Quadrivalent HPV vaccine could significantly reduce the acquisition of infection and clinical disease caused by HPV types 6, 11, 16 and 18.