>> P-690: A TWO DOSE HPV VACCINE SCHEDULE IN GIRLS: IMMUNOGENICITY AT 24 MONTHS

19:00 PM - 19:00 PM

Simon Dobson1, M. Dawar1, T. Kollmann1, S. McNeil2, S. Halperin2, J. Langley2, M. Dionne3, M-E Picard3, C. Sauvageau3, M. Krjaden1.

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:

  Group 1 vs.
Group 2		 Group 1 vs.
Group 3		 Group 2 vs.
Group 3
HPV 6 0.77 (0.62, 0.96) 1.42 (1.14, 1.76) 1.84 (1.47, 2.29)
HPV 11 0.88 (0.7, 1.09) 1.4 (1.13, 1.74) 1.6 (1.28, 1.99)
HPV 16 0.81 (0.64, 1.02) 1.76 (1.4, 2.22) 2.17 (1.72, 2.75)
HPV 18 0.49 (0.36, 0.69) 1.46 (1.06, 2.01) 2.94 (2.13, 4.07)

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

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