3007 Background: Although prevalence of oncogenic HPV infection is highest in women younger than 25, incident infection is estimated to occur in 5% - 10% of women aged 25–55. New infections decrease with age, but the proportion that persists is higher. Therefore, women over 25 also may benefit from HPV vaccination. In a primary Phase III study (GSK 105879/014), an HPV-16/18 AS04 cervical cancer vaccine candidate was highly immunogenic and well tolerated in women up to age 55. This extension study evaluates the persistence of immune response and safety through 18 months after the first vaccine dose. Methods: Healthy women aged 15–55 years in Germany and Poland who had received 3 doses of HPV-16/18 L1 AS04 VLP vaccine at months 0, 1, and 6 in the primary study were invited to participate in a follow-up extension (15–25 years [n=169], 26–35 years [n=83], 36–45 years [n=89], and 46–55 years [n=176]). Immunogenicity and safety were assessed up to 18 months after vaccination. Results: At 18 months, 100% of subjects remained seropositive for both antigens in all age groups. For HPV-16, GMCs were 2,220.1 in women 15–25, 1,276.9 in women 26–35, 905.6 in women 36–45, and 809.0 in women 46–55. For HPV-18, GMCs were 828.2 in women 15–25, 441.8 in women 26–35, 289.7 in women 36–45, and 275.5 in women 46–55. In women over 25, GMCs tended to be higher in those initially seropositive. In the oldest age group, HPV-16 and HPV-18 GMCs remained at least 10-fold higher than natural infection levels reported in another study.The HPV-16/18 AS04 vaccine was well tolerated among all age groups. Conclusions: The HPV-16/18 AS04 vaccine candidate was highly immunogenic and well-tolerated. As with other vaccines, an age- dependent decrease in GMCs was observed, but GMCs remained substantially higher than natural infection levels previously reported in women 15–25. More importantly, GMCs at month 18 for women over 25 remained in the same range as GMCs observed in another study in women 15- 25 that were associated with sustained efficacy up to 4.5 years. Thus, in women up to age 55, an HPV-16/18 AS04 vaccine may protect against new infections with oncogenic HPV types that can cause cervical cancer. [Table: see text]
PCN32 COST-EFFECTIVENESS ANALYSIS OF AN HPV-16/18 PROPHYLACTIC CERVICAL CANCER VACCINE IN A SETTING OF EXISTING SCREENING IN PORTUGAL-RESULTS FROM A MATHEMATICAL MODEL