The 9-valent human papillomavirus (9vHPV) vaccine targets the four HPV types (HPV6/11/16/18) covered by the quadrivalent HPV (qHPV) vaccine, with the addition of the five oncogenic types most commonly associated with cervical cancer after HPV16/18 (HPV31/33/45/52/58). Primary analyses of a study in young women 16-26 years of age demonstrated efficacy of 9vHPV vaccine against HPV31/33/45/52/58-related infections and disease, and non-inferior HPV6/11/16/18 antibody responses when compared with qHPV vaccine. This presentation evaluates study outcomes, including efficacy for up to 6 years following first administration and antibody responses. Additionally, vaccination impact on cervical cytology abnormalities and related therapeutic procedures are reported.
In this randomized, double-blind study (Protocol V503-001; NCT00543543), participants (N=14,215) received a three-dose series of 9vHPV or qHPV (control) vaccine. Cervical and external genital swabs for HPV-DNA testing, and cervical cytological samples for Papanicolaou staining were collected regularly. Tissue samples from biopsy or cervical definitive therapy (loop electrosurgical excision procedure, conization) were tested for HPV DNA. Serum antibody responses to the nine vaccine HPV types were assessed.
In the pre-specified, per-protocol population (susceptible population), efficacy against HPV31/33/45/52/58-related cervical intraepithelial neoplasia Grade 3 (CIN 3) was 100% (95% CI: 39·4, 100). Efficacy against HPV31/33/45/52/58-related cervical, vulvar, and vaginal disease; persistent infection; cytological abnormalities; cervical biopsy; and cervical definitive therapy ranged from 90-98%. Incidence of HPV6/11/16/18-related persistent infection, disease, cytological abnormalities, and procedures was similar in 9vHPV and qHPV vaccine recipients. Antibodies to the HPV types targeted by each vaccine persisted through 5 years following vaccination. Geometric mean titer ratios (9vHPV/qHPV) for HPV6/11/16/18 remained stable over time. Administration of a fourth dose to a subset of participants 5 years after vaccination resulted in a rapid increase of GMTs for all 9 HPV types, which is indicative of immune memory.
The 9vHPV vaccine prevents >90% HPV31/33/45/52/58-related infection, cytological abnormalities, high-grade lesions, and cervical procedures in a prophylactic setting. Both vaccines protected against HPV6/11/16/18-related infection, cytological abnormalities, and high-grade disease and had a similar immunogenicity profile with respect to HPV6/11/16/18. Vaccine efficacy was sustained for up to 6 years.