Comparison of the immunogenicity and safety ofCervarix™ andGardasil®human papillomavirus (HPV) cervical cancer vaccines in healthy women aged 18–45 years

This observer-blind study compared the prophylactic human papillomavirus (HPV) vaccines, Cervarix (GlaxoSmithKline) and Gardasil (Merck), by assessing immunogenicity and safety through one month after completion of the three-dose vaccination course. Women (n = 1106) were stratified by age (18-26, 27-35, 36-45 years) and randomized (1:1) to receive Cervarix (Months 0, 1, 6) or Gardasil (Months 0, 2, 6). At Month 7 after first vaccination, all women in the according-to-protocol cohort who were seronegative/DNA negative before vaccination for the HPV type analyzed had seroconverted for HPV-16 and HPV-18 serum neutralizing antibodies, as measured by pseudovirion-based neutralization assay (PBNA), except for two women aged 27-35 years in the Gardasil group who did not seroconvert for HPV-18 (98%). Geometric mean titers of serum neutralizing antibodies ranged from 2.3-4.8-fold higher for HPV-16 and 6.8-9.1-fold higher for HPV-18 after vaccination with Cervarix compared with Gardasil, across all age strata. In the total vaccinated cohort (all women who received at least one vaccine dose, regardless of their serological and DNA status prior to vaccination), Cervarix induced significantly higher serum neutralizing antibody titers in all age strata (p or= 84%) for both vaccines. Although the importance of differences in magnitude of immune response between these vaccines is unknown, they may represent determinants of duration of protection against HPV-16/18. Long-term studies evaluating duration of efficacy after vaccination are needed for both vaccines.