Long-term Immunogenicity and Safety of the AS04-adjuvanted Human Papillomavirus-16/18 Vaccine in Four- to Six-year-old Girls: Three-year Follow-up of a Randomized Phase III Trial.

BACKGROUND: The burden of human papillomavirus (HPV) diseases is high in Latin America. HPV vaccines licensed from 2006 onwards offer protection against most HPV-related cancers, especially when introduced into national immunization programs. Barriers to optimal vaccine uptake are, however, lowering the impact of adolescent HPV vaccination programs. Immunization of children might overcome these barriers and be a strategy of choice for some countries. METHODS: This multicenter phase III randomized, controlled, single-blind study (NCT01627561) was conducted in Colombia, Mexico and Panama to assess safety and immunogenicity of 2-dose vaccination with AS04-adjuvanted HPV-16/18 vaccine in girls 4-6 years of age. We report safety outcomes and anti-HPV-16/18 antibody titers measured by enzyme-linked immunosorbent assay in HPV-vaccinated girls that were followed over a 36-month period. RESULTS: Over 36 months (ie, 30 months after the second vaccine dose), among 74 girls included in the HPV group, 1 serious adverse event unrelated to vaccination has been reported. No withdrawal because of (serious) adverse events has been reported. At month 36, all girls in the per-protocol-cohort were still seropositive for anti-HPV-16 and anti-HPV-18 with geometric mean concentrations of 1680.6 and 536.4 enzyme-linked immunosorbent assay units/mL, respectively. CONCLUSIONS: The AS04-adjuvanted HPV-16/18 vaccine administered according to a 2-dose schedule to girls 4-6 years of age induced a high and sustained immunologic response with an acceptable safety profile during the 30 months following vaccination.

Safety and Immunogenicity of the HPV-16/18 AS04-adjuvanted Vaccine in 4-6-year-old Girls: Results to Month 12 From a Randomized Trial.

BACKGROUND: The burden of cervical cancer caused by human papillomavirus (HPV) is high in Latin America. The suboptimal HPV vaccination coverage in adolescents could be improved by pediatric immunization. HPV vaccination has not yet been reported in girls <9 years of age. METHODS: This ongoing phase III, controlled, randomized, single-blind, multicenter study conducted in Colombia, Mexico and Panama (NCT01627561) evaluated the safety and immunogenicity of AS04-HPV-16/18 vaccine in 4-6-year-old girls. Healthy girls (randomized 1:1) received either 2 doses of AS04-HPV-16/18 vaccine (HPV group, N=74) or 1 dose of each measles-mumps-rubella and diphtheria-tetanus-acellular-pertussis vaccines (control group, N=74) 6 months apart. We report the safety and serum anti-HPV-16 and anti-HPV-18 antibodies (measured by enzyme-linked immunosorbent assay) up to 6 months postvaccination, that is, month (M) 12. RESULTS: Injection site pain was the most frequently reported solicited local symptom in HPV vaccinees. The incidence of other solicited and unsolicited symptoms after each vaccination was similar between the HPV and control group. Until M12, 1 girl in the HPV group and 2 in the control group reported serious adverse events; all serious adverse events were assessed as unrelated to study vaccines. No potential immune-mediated diseases were identified. All girls seroconverted for both antigens after 2 doses of AS04-HPV-16/18. In initially seronegative girls, anti-HPV-16 geometric mean concentrations were 20080.0 enzyme-linked immunosorbent assay units (EU)/mL at M7 and 3246.5 EU/mL at M12; anti-HPV-18 geometric mean concentrations were 10621.8 EU/mL at M7 and 1216.6 EU/mL at M12. CONCLUSIONS: Two-dose vaccination with AS04-HPV-16/18 was well tolerated and induced adequate antibody responses in 4-6-year-old girls.