>> P-690: A TWO DOSE HPV VACCINE SCHEDULE IN GIRLS: IMMUNOGENICITY AT 24 MONTHS
19:00 PM - 19:00 PM
1University of British Columbia, Vancouver, BC, Canada; 2Dalhousie University, Halifax, NS, Canada; 3Centre de Recherche du CHUL, Québec, QC, Canada; 4ritish Columbia Ministry of Health, BC, Canada.
Additional Author(s) & Affiliation(s): Marra F1, Miller D1, Money D1, Naus M1, Ogilvie G1, Singer J1, Bettinger J1, Young E4.Background: One month after the second dose of a two dose (0,6 month) schedule using quadrivalent HPV vaccine (Q-HPV) in 9-13 year old girls, the antibody responses to HPV-16,18,6,11 were non-inferior to 3 dose regimens in both young adult women and 9-13 year old girls. Presented is follow up immunogenicity at 24 months post dose 1 . Objectives: To determine if the antibody responses to HPV-16,18,6,11 remain non-inferior at month 24, following a 2 dose pediatric regimen as compared to a 3-dose adult regimen.
Methods: In this phase III, post licensure randomized controlled multi-centre trial the three groups and treatment regimens were as follows:
1) Healthy girls, 9-13 years old–2 doses Q-HPV vaccine at 0, 6 months, (n=194)
2) Healthy girls, 9-13 years old–3 doses of Q-HPV vaccine at 0, 2 and 6 month (n=187)
3) Healthy 16-26 year olds–3 doses of Q-HPV vaccine at 0, 2 and 6 months (n=203)
Blood at Month 24 was evaluated using Merck Competitive Luminex ImmunoAssay (cLIA) to assess serum antibody concentrations to HPV-16,-18,-6 and -11. An Analysis of Variance (ANOVA) to test differences in the Geometric Mean Titres (GMTs) were performed. Non-inferiority of any treatment arm was declared if lower bounds of the 95%CIs of GMT ratios were greater than 0.5.
Results: GMT Ratios (95% CI) were:
Conclusions: Following a 2 dose pediatric regimen, antibody responses to HPV-16, 18,6,11 remained non-inferior at month 24, as compared to a 3-dose regimen in young adult women. Compared to a 3 dose pediatric regimen, a dose 2 pediatric regimen was non-inferior for HPV-16,6,11 but not for HPV-18.
Additional Authors: F. Marra1, D. Miller1, D. Money1, M. Naus1, G. Ogilvie1, J. Singer1, J. Bettinger, E. Young4