Immunogenicity, reactogenicity, and safety of human papillomavirus 16/18 AS04-adjuvanted vaccine in Japanese women: interim analysis of a phase II, double-blind, randomized controlled trial at month 7.

A phase II, double-blind, controlled randomized multicenter study with human papillomavirus (HPV) 16/18 AS04 (3-O-desacyl-4'-monophosphoryl lipid A and aluminum hydroxide)-adjuvanted vaccine is ongoing in Japanese women aged 20 to 25 years. An interim analysis was performed at month 7 (1 month after the third dose of vaccine) to determine reactogenicity, safety, and immunogenicity of the vaccine and to evaluate the baseline HPV-16/18 seropositivity and DNA status of women. In the HPV-16/18 group (according-to-protocol cohort for immunogenicity analysis), 100% seroconversion was observed against HPV-16 and HPV-18 at month 6 (5 months after the second dose) and at month 7. At month 7, anti-HPV-16 geometric mean titer (GMT) was 7441.0 enzyme-linked immunosorbent assay units/mL and anti-HPV-18 GMT was 3805.4 enzyme-linked immunosorbent assay units/mL, which is, respectively, 250- and 168-fold higher than GMTs observed after natural infection with HPV-16 or HPV-18. In the total vaccinated cohort, the seropositivity rates against HPV-16 and HPV-18 at study entry were 17.3% and 15.8%, respectively. At the same time point, HPV-16 and HPV-18 DNA was detected in 6.5% and 4.0% of the women, respectively. The immunogenicity of the HPV-16/18 vaccine and the HPV prevalence before vaccination in Japanese women are in line with what was observed in other populations. Injection site symptoms and some general symptoms were reported more frequently in the HPV-16/18 group than in the hepatitis A vaccine group but had no impact on compliance with completion of the vaccination course. Overall, the HPV-16/18 vaccine had a good safety profile, was well tolerated, and is highly immunogenic in the study population of Japanese women.