A Randomized, Double-Blind, Phase III Study of the Immunogenicity and Safety of a 9-Valent Human Papillomavirus L1 Virus-Like Particle Vaccine (V503) Versus Gardasil® in 9-15-Year-Old Girls

Background: A 9-valent human papillomavirus (9vHPV) vaccine has been developed to prevent infections and diseases related to HPV 6/11/16/18 [as per the licensed quadrivalent HPV (qHPV) vaccine], as well as 5 additional oncogenic HPV types (HPV 31/33/45/52/58). Compared with the qHPV vaccine, the 9vHPV vaccine potentially increases the coverage of protection from 70% to 90% of cervical cancers. We compared the immunogenicity and safety of the 9vHPV vaccine versus the qHPV vaccine in 9-15-year-old girls. Methods: Participants (n = 600) were randomized to receive 9vHPV or qHPV vaccines on day 1, month 2 and month 6. Serology testing was performed on day 1 and month 7. HPV type-specific antibody titers (anti-HPV 6/11/16/18/31/33/45/52/58) were determined by competitive Luminex immunoassay and expressed as geometric mean titers and seroconversion rates. Vaccine safety was also assessed. Results: The HPV 6/11/16/18 immune responses elicited by the 9vHPV vaccine were comparable with those elicited by the qHPV vaccine. All participants (except 1 for HPV 45) receiving the 9vHPV vaccine seroconverted for HPV 31/33/45/52/58. The 9vHPV and qHPV vaccines showed comparable safety profiles, although the incidence of injection-site swelling was higher in the 9vHPV vaccine group. Conclusions: In addition to immune responses to HPV 31/33/45/52/58, a 3-dose regimen of the 9vHPV vaccine elicited a similar immune response to HPV 6/11/16/18 when compared with the qHPV vaccine in girls aged 9-15 years. The safety profile was also similar for the 2 vaccines.