We describe the final 10-year data for the long-term follow-up (LTFU) study of the 4vHPV vaccine in pre-adolescents and adolescents.
In the base study (V501-018), 1661 sexually naïve males and females received 4vHPV vaccine (EVG; Early Vaccination Group, followed for 9.9.years) or placebo at day 1, months 2 and 6. Thereafter at month 30, the placebo group (CVG; Catch Up Vaccination Group, followed for 7.4 years) received 4vHPV vaccine using the same dosing schedule. Long term anti- HPV type 6, 11, 16 and 18 immune responses were assessed. Effectiveness was estimated by calculating the incidence rate of the primary endpoints (HPV6/11/16/18 related disease or persistent infection).
For each of HPV types 6, 11 and 16, 89%-96% of subjects remained seropositive through 10-years post-vaccination. The preadolescents had 38%-65% higher GMTs at month 7 which remained 16%-42% higher at 10 years compared to the adolescents. No cases of HPV type 6, 11, 16 and 18-related disease were observed. Ten subjects had persistent infection of ≥6months duration with vaccine-type HPV (females: 0.3/100 person-years at risk (EVG & CVG); males: 0.6/100 person-years at risk (EVG) and 0.4/100 person-years at risk (CVG). Infection persisted for ≥12 months in 2 subjects. No new serious adverse events were reported through 10 years.
A 3- dose regimen of the 4vHPV vaccine was immunogenic, clinically effective, and generally well tolerated in pre-adolescents and adolescents during 10 years of follow-up. These long term findings support efforts to vaccinate this population against HPV prior to exposure.