Second HPV Vaccine Shows Early Positive Results
Adapted from the NCI Cancer Bulletin.
Positive interim results for a candidate vaccine to prevent persistent infections by human papillomavirus (HPV) types 16 and 18 were published in the June 30, 2007, issue of The Lancet (see the journal abstract). The vaccine Cervarix® was 90 percent effective in preventing grade 2 or 3 cervical intraepithelial neoplasia (CIN2+) that contained DNA from either virus type.
The results come from a large international trial of 18,644 women aged 15-25 sponsored by the drug's manufacturer, GlaxoSmithKline Biologicals (see the protocol summary). The trial design called for analysis of early results after 23 cases of CIN2+ were detected. Two of these cases were among the 9,258 women receiving the vaccine, and 21 were among the 9,267 controls who received a hepatitis A vaccine. The mean follow-up time was 14.8 months.
In an editorial, Drs. Jessica A. Kahn of the University of Cincinnati and Robert D. Burk of the Albert Einstein College of Medicine in New York wrote, "These interim data are encouraging." But they noted that the paper does not provide information about the public health impact of vaccination "in real world settings" because the report does not provide estimates of the reduction in overall rates of CIN2+. They stress that vaccination of young adolescents is likely to have the greatest public health benefit, but that continued screening will still be required after vaccination.
A separate phase III trial testing Cervarix, cosponsored by the National Cancer Institute with support from the National Institutes of Health's Office for Research on Women's Health and the Costa Rica Ministry of Health, is now underway in Costa Rica. This trial should provide additional information about the public health impact and efficacy of the vaccine.
Longer-term data on the vaccine's overall efficacy (see the journal abstract) and efficacy against other oncogenic HPV types (see the journal abstract) were subsequently published in Lancet Oncology.