Fraction of cervical neoplasias due to human papillomavirus 16 and 18 in vaccine trials

✍ Scribed by Silvia Franceschi; Gary M. Clifford

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: French
• Weight: 43 KB
• Volume: 122
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.23112

✦ Synopsis

Dear Sir,

Large randomized clinical trials, including nearly 40,000 women, on the efficacy of two virus-like particle-based vaccines against human papillomavirus (HPV)6/11/16/18 1 and HPV16/18 2 have been recently published. Among women with no sign of previous infection with the HPV types included in the vaccines, immunization efficacy against cervical intraepithelial neoplasia (CIN) grades 2 and 3, and adenocarcinoma in situ (AIS) caused by HPV16 and 18 approached 100%. 1,2 Conversely, efficacy of the quadrivalent vaccine against all CIN2 and 3 and AIS in intention-to-treat analysis trials was 18% (95% confidence interval: 7-29%), firstly on account of the substantial proportion of women who were HPV16 or 18positive at entry into the study, and secondly on account of CIN2 and 3 caused by types other than HPV16 and 18. 1 An interesting finding of the HPV vaccine trials was the high overall incidence of CIN2 and 3 (2.5 3 and 2.0 4 per 100 women-years) in the placebo groups of the two quadrivalent vaccine trials (the corresponding information has not yet been reported in the bivalent vaccine trials). 2 Thus, trial findings confirmed, on a much larger scale than ever before, that CIN2 and 3 can be frequently detected in intensively screened teenagers and women in their twenties. 5,6 Whether these lesions differ in terms of aetiology, i.e., the contribution of different HPV types, and prognosis, from those found in older women is not clear, but is important for the validity of vaccine trial endpoints. As CIN2 and 3 in vaccine trial participants were routinely treated, we cannot know what proportion of these lesions among young women would have natu-