Clinical update of the AS04-Adjuvanted human Papillomavirus-16/18 cervical cancer vaccine, cervarix®

摘要

Persistent infection with human papillomavirus (HPV) is a necessary cause of cervical cancer, resulting annually in 274,000 deaths worldwide. Two prophylactic HPV vaccines are licensed in >100 countries, and immunization programs in young, adolescent girls have been widely implemented. HPV-16/18 AS04-adjuvanted vaccine (Cervarix®; GlaxoSmithKline Biologicals, Rixensart, Belgium) has demonstrated type-specific protection against the five most frequent cancer-causing types (16, 18, 31, 33, and 45) that are responsible for 82% of invasive cervical cancers globally. Cervarix® has demonstrated efficacy against HPV-45, which is the third most common HPV type in cervical cancer and adenocarcinoma. Final results of a large phase 3 trial recently showed Cervarix® substantially reduced the overall burden of cervical precancerous lesions (cervical intraepithelial neoplasia 2+) by 70.2% in an HPV-naïve population approximating young girls prior to sexual debut, the target of most current vaccination programs. Protection offered by Cervarix® against nonvaccine types (mainly 31, 33, and 45) might potentially allow for 11%–16% additional protection against cervical cancers, compared to a vaccine only offering protection against HPV-16/18. Another recent study directly compared the antibody response of Cervarix® to that of quadrivalent HPV-6/11/16/18 vaccine (Gardasil®; Merck, Whitehouse Station, NJ, USA). Cervarix® induced significantly superior neutralizing antibody levels as compared with Gardasil® for HPV-16 and HPV-18 in all age groups studied. This may translate into more women having detectable (neutralizing) antibodies in cervicovaginal secretions for HPV-16 and HPV-18 after vaccination with Cervarix® when compared with Gardasil®. Cervarix® induced significantly higher frequencies of antigen-specific memory B-cells and T-cells in responders for HPV-16 and HPV-18 as compared with Gardasil®. Cervarix® continues to show sustained high levels of total and neutralizing antibodies for HPV-16 and HPV-18, 7.3 years after vaccination. This is associated with high efficacy and no breakthrough cases in the HPV-naïve population, and is the longest duration follow-up for safety, immunogenicity, and efficacy for any licensed HPV vaccine to date.