Randomised open trial comparing 2-dose regimens of the Human Papillomavirus 16/18 AS04-adjuvanted vaccine in girls aged 9-14 years versus a 3-dose regimen in women aged 15-25 years

BACKGROUND: This randomized, open trial compared regimens including 2 doses (2D) of human papillomavirus (HPV) 16/18 AS04-adjuvanted vaccine in girls aged 9-14 years with one including 3 doses (3D) in women aged 15-25 years. METHODS: Girls aged 9-14 years were randomized to receive 2D at months 0 and 6 (M0,6; (n = 550) or months 0 and 12 (M0,12; n = 415), and women aged 15-25 years received 3D at months 0, 1, and 6 (n = 482). End points included noninferiority of HPV-16/18 antibodies by enzyme-linked immunosorbent assay for 2D (M0,6) versus 3D (primary), 2D (M0,12) versus 3D, and 2D (M0,6) versus 2D (M0,12); neutralizing antibodies; cell-mediated immunity; reactogenicity; and safety. Limits of noninferiority were predefined as <5% difference in seroconversion rate and