In this phase 3, double-blind, randomised controlled trial, healthy women older than 25 years were enrolled (age stratified: 26–35 years, 36–45 years, and ≥46 years). Up to 15% in each age stratum had a history of HPV infection or disease. Women were randomly assigned (1:1) to receive HPV 16/18 vaccine or aluminium hydroxide control, with an internet-based system. The primary endpoint was vaccine efficacy against 6-month persistent infection or cervical intraepithelial neoplasia grade 1 or greater (CIN1+) associated with HPV 16/18. We did analyses in the according-to-protocol cohort for efficacy and total vaccinated cohort. Data for the combined primary endpoint in the according-to-protocol cohort for efficacy were considered significant when the lower limit of the 96·2% CI around the point estimate was greater than 30%. For all other endpoints and cohorts, data were considered significant when the lower limit of the 96·2% CI was greater than 0%. This study is registered with terrefs10" class="interref" data-locatorType="url" data-locatorKey="http://ClinicalTrials.gov">ClinicalTrials.gov, number terrefs20" class="interref" data-locatorType="ctgov" data-locatorKey="NCT00294047">NCT00294047.
The first participant was enrolled on Feb 16, 2006, and the last study visit took place on Jan 29, 2014. 4407 women were in the according-to-protocol cohort for efficacy (n=2209 vaccine, n=2198 control) and 5747 women in the total vaccinated cohort (n=2877 vaccine, n=2870 control). At month 84, in women seronegative for the corresponding HPV type in the according-to-protocol cohort for efficacy, vaccine efficacy against 6-month persistent infection or CIN1+ associated with HPV 16/18 was significant in all age groups combined (90·5%, 96·2% CI 78·6–96·5). Vaccine efficacy against HPV 16/18-related cytological abnormalities (atypical squamous cells of undetermined significance and low-grade squamous intraepithelial lesion) and CIN1+ was also significant. We also noted significant cross-protective efficacy against 6-month persistent infection with HPV 31 (65·8%, 96·2% CI 24·9–85·8) and HPV 45 (70·7%, 96·2% CI 34·2–88·4). In the total vaccinated cohort, vaccine efficacy against CIN1+ irrespective of HPV was significant (22·9%, 96·2% CI 4·8–37·7). Serious adverse events related to vaccination occurred in five (0·2%) of 2877 women in the vaccine group and eight (0·3%) of 2870 women in the control group.
In women older than 25 years, the HPV 16/18 vaccine continues to protect against infections, cytological abnormalities, and lesions associated with HPV 16/18 and CIN1+ irrespective of HPV type, and infection with non-vaccine types HPV 31 and HPV 45 over 7 years of follow-up.
GlaxoSmithKline Biologicals SA.