Poster Presentations

Session Title: VACCINE AND PREVENTION

LONG-TERM SAFETY AND IMMUNOGENICITY OF A HUMAN PAPILLOMAVIRUS (HPV)-16/18 AS04‑ADJUVANTED CERVICAL CANCER VACCINE IN GIRLS AGED 10‑14 YEARS: 36-MONTH FOLLOW-UP

T. Schwarz¹, M. Rivera², A. Valencia³, A. De Velasquez⁴, L.-M. Huang⁵, M. Rapp⁶, G. Catteau⁷, F. Thomas⁷, D. Descamps^7
1Central Laboratory and Vaccination Centre, Stiftung Juliusspital, Wuerzburg, Germany, ²Organizaciòn para el Desarrollo y la Investigación Salud en Honduras, Tegucigalpa, Honduras, ³Fundacion Santa Fe de Bogotá, Bogotá, Colombia, ⁴Centro Médico America, La Chorrera, Panama, ⁵National Taiwan University Hospital, Taipei, Taiwan R.O.C., ⁶Praxis, Nordrhein-Westfalen, Germany, ⁷GlaxoSmithKline Biologicals, Rixensart, Belgium

Background and aims: A strong and long-lasting immune response against high-risk HPV types is critical when prophylactic vaccination against cervical cancer takes place prior to sexual debut. The HPV-16/18 AS04-adjuvanted vaccine has previously been shown to be highly immunogenic and generally well-tolerated when administered to pre-teen and adolescent girls. This open extension (104904/NCT00316706) of a phase III, randomized, controlled, multi-country study was designed to evaluate the long-term immunogenicity and safety of the vaccine. We report interim results up to Month 36.
Methods: Immunogenicity (ELISA) and safety were assessed in girls aged 10-14 years who had received 3 doses of the HPV‑16/18 AS04-adjuvanted vaccine (n=601) at 0, 1 and 6 months.
Results: 36 months after the first vaccine dose, 100% of girls (n=575, ATP cohort) were seropositive for anti‑HPV‑16 and ‑18 antibodies. Anti-HPV-16 GMTs were 2688.6 EL.U/mL (95% CI: 2503.6, 2887.3) and anti-HPV-18 GMTs were 995.0 EL.U/mL (95% CI: 918.1, 1078.4). Anti-HPV-16 and HPV-18 antibody levels peaked at Month 7 then gradually declined. At Month 36, antibody titers were notably higher than the plateau level observed in a phase IIB efficacy study (580299/007; NCT00518336), which was associated with sustained protection against HPV-16 and HPV-18 infections. No vaccine-related SAEs, or withdrawals due to adverse events, were reported over the 36-month follow-up.
Conclusions: The HPV-16/18 AS04‑adjuvanted vaccine was immunogenic and generally well‑tolerated in girls aged 10-14 years through 36 months, with antibody levels likely to result in sustainable long-term protection.
On behalf of the HPV Adolescent Study Investigators Network.