Source: DocGuide.com
Author: Jenny Powers

NICE, France — May 11, 2010 — The human papillomavirus (HPV) vaccine (types 16 and 18) AS04-adjuvanted vaccine shows a sustained immune response, as demonstrated by high levels of neutralising antibodies, up to 8.4 years after first vaccination, researchers said here at the 28th Annual Meeting of the European Society for Paediatric Infectious Diseases (ESPID) on May 6.

Cecelia Maria Roteli-Martins, MD, Hospital Leonor Mendes de Barros-Secretaria d Saude de São Paulo, in São Paulo, Brazil, headed an international team that evaluated the efficacy and immunogenicity of the HPV-16/18 AS04-adjuvanted vaccine by measuring neutralising antibody levels in a follow-up analysis yearly for up to 8.4 years post vaccination

Healthy women aged 15 to 25 years who were DNA-negative for oncogenic HPV types, 16 and 18 with normal cytology at baseline received the vaccine (n = 560) or placebo (n = 553).

A total of  223 women who were vaccinated with the active vaccine returned for extension studies, as well as 213 of the women who were given placebo. In these women, HPV-16 and 18 antibodies were measured annually.

Cervical samples were taken every 6 months and gynaecological and cytopathological examinations were performed every 12 months.

All (100%) of the women in the trial have remained seropositive for HPV-16 and -18 antibodies.

After 2 years of follow-up, 5 incident infections and 1 infection of low grade squamous intra-epithelial lesion or higher (LSIL) associated with HPV 16 and 18 occurred in the placebo group.

The vaccine efficacy against HPV-16/18-associated endpoints up to 8.4 years was 95.1% (84.6, 99.0), 100% (79.8, 100), 100% (56.1, 100), 94.6% (65.7, 99.9), and 100% (<0, 100) for incident infection, 6-month persistent infection, 12-month persistent infection, >=LSIL and cervical intraepithelial neoplasia grade 2 or higher, respectively.

No difference in safety profile was observed between vaccinated and placebo groups.

Funding for this study was provided by GlaxoSmithKline.

[Presentation title: Sustained Immunogenicity and Efficacy of the HPV-16/18 AS04-Adjuvanted Vaccine: Follow-up to 8.4 Years. Abstract 622]