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Lancet Oncol. 2015 Jul;16(7):775-86. doi: 10.1016/S1470-2045(15)00047-9. Epub 2015 Jun 9.

Efficacy of fewer than three doses of an HPV-16/18 AS04-adjuvanted vaccine: combined analysis of data from the Costa Rica Vaccine and PATRICIA Trials.

Author information

1
Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA. Electronic address: kreimera@mail.nih.gov.
2
GSK Vaccines, Wavre, Belgium.
3
Department of Obstetrics and Gynecology, San Pablo Colleges Medical Center, San Pablo City, Philippines.
4
Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
5
Vaccine Trials Group, Telethon Institute for Child Health Research, Perth, WA, Australia; Sydney University Discipline of Paediatrics and Child Health, Children's Hospital at Westmead, Sydney, NSW, Australia.
6
Microbiology and Infectious Diseases Department, Royal Women's Hospital and Department of Obstetrics and Gynaecology, University of Melbourne, Murdoch Childrens Research Institute Melbourne, VIC, Australia.
7
Proyecto Epidemiologico Guanacaste, San José, Costa Rica; Section of Early Detection and Prevention, International Agency for Research on Cancer, Lyon, France.
8
Departments of Pathology and Obstetrics and Gynecology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA. Electronic address: cwheeler@salud.unm.edu.

Abstract

BACKGROUND:

There is some evidence to suggest that one or two doses of the HPV vaccine provides similar protection to the three-dose regimen. The main aim of the study was to ascertain HPV-16/18 vaccine efficacy in both full and naive cohorts and to explore protection conferred against non-vaccine HPV types, by number of doses received.

METHODS:

Summary data from the Costa Rica Vaccine Trial (CVT; NCT00128661) and ~the PATRICIA trial (NCT001226810), two phase 3, double-blind, randomised controlled clinical trials of the HPV-16/18 AS04-adjuvanted vaccine in young women, were combined in a post-hoc analysis (GlaxoSmithKline [GSK] e-track number 202142) to investigate the efficacy of fewer than three doses of the HPV-16/18 vaccine after 4 years of follow-up. Women were randomly assigned to receive three doses of the HPV-16/18 vaccine or to a control vaccine; yet, some received fewer doses. After exclusion of women with less than 12 months of follow-up or those who were HPV-16/18 DNA-positive at enrolment (for the HPV-16/18 endpoint), we calculated vaccine efficacy against one-time detection of incident HPV infections after three, two, and one dose(s). The primary study endpoint was one-time detection of first incident HPV-16/18 infections accumulated during the follow-up phase.

FINDINGS:

We assessed vaccine efficacy against incident HPV-16/18 infection in the modified total vaccinated cohort (22 327 received three doses, 1185 two doses, 543 one dose). Vaccine efficacy against incident HPV-16/18 infections for three doses was 77·0% (95% CI 74·7-79·1), two doses was 76·0% (62·0-85·3), and one dose was 85·7% (70·7-93·7). Vaccine efficacy against incident HPV-31/33/45 infections for three doses was 59·7% (56·0-63·0), two doses was 37·7% (12·4-55·9), and one dose was 36·6% (-5·4 to 62·2). Vaccine efficacy against incident HPV-16/18 infection for two-dose women who received their second dose at 1 month was 75·3% (54·2-87·5) and 82·6% (42·3-96·1) for those who received the second dose at 6 months (CVT data only). Vaccine efficacy against HPV-31/33/45 for two-dose women who received their second dose at 6 months (68·1%, 27·0-87·0; CVT data only), but not those receiving it at one month (10·1%, -42·0 to 43·3), was similar to the three-dose group.

INTERPRETATION:

4 years after vaccination of women aged 15-25 years, one and two doses of the HPV-16/18 vaccine seem to protect against cervical HPV-16/18 infections, similar to the protection provided by the three-dose schedule. Two doses separated by 6 months additionally provided some cross-protection. These data argue for a direct assessment of one-dose efficacy of the HPV-16/18 vaccine.

FUNDING:

US National Cancer Institute, National Institutes of Health Office of Research on Women's Health, and Ministry of Health of Costa Rica (CVT); GlaxoSmithKline Biologicals SA (PATRICIA).

PMID:
26071347
PMCID:
PMC4498478
DOI:
10.1016/S1470-2045(15)00047-9
[Indexed for MEDLINE]
Free PMC Article

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