The investigational vaccine, Gardasil is designed to prevent infection from four common quadrivalent human papillomavirus (HPV) types and related cervical cancer, cervical pre-cancers and genital warts.
The trial was the first to evaluate immune response and tolerability among young adolescents aged 10 to 15 years. The study involved over 1520 mix-sex subjects with an age range of 10 to 23 years. Each participant received three injections of Gardasil over a six-month period before being tested to see how well the vaccine was able to stimulate specific immune responses.
The results show that Gardasil significantly reduced the combined incidence of persistent HPV infections and related disease, including new cervical pre-cancers and genital warts in young adult women.
The data indicates that although effective at all ages and sexes tested, the vaccine has most impact in the youngest group, i.e. the response of young adolescents was even greater than that of the young adults. This finding controversially suggests that it would be better to vaccinate children during their pre-teenage years before they become sexually active.
Phase III clinical trials to evaluate the safety and efficacy of Gardasil are currently underway with over 25,000 participants enrolled worldwide. Phase III data are expected to be available later this year.