Bivalent HPV vaccine may provide cross- protection against additional oncogenic types

The bivalent HPV may protect against five of the most common oncogenic HPV types.

At the recent Infectious Diseases Society of America meeting, held in Philadelphia, Barbara Romanowski, MD, of the University of Alberta in Edmonton, Canada, presented phase-3 data from PATRICIA. The trial was conducted to evaluate the vaccine’s (Cervarix, GlaxoSmithKline) efficacy against HPV types 16 and 18, which are included in the vaccine, and three nonvaccine types — 31, 33 and 45.

The researchers compared the incidence of cervical intraepithelial neoplasia (CIN) among women aged 15 to 25 years who were administered the vaccine (n=9,319) and a control group (n=9,325).

Data indicated vaccine efficacy of 98.4% (P<.0001) against types 16 and 18, with one case of CIN2+ in the vaccine group compared with 63 cases in the control group.

Similar results were observed when HPV types 31, 33 and 45 were included in the analysis. Six cases were associated with these types in the vaccine group compared with 88 cases in the control group, for a vaccine efficacy of 93.2% (P<.0001).

“Protection against nonvaccine oncogenic HPV types 31/33/45 would therefore result in the prevention of an additional 32.5% of CIN2+ cases, as compared to a vaccine that would only offer protection against HPV-16/18,” Romanowski said.

After extrapolating these data to the public health setting, the researchers projected that the vaccine could prevent 394 cases associated with types 16 and 18 and 522 cases associated with types 31, 33 and 45 per 100,000 patient-years of follow-up. – by Nicole Blazek

Romanowski B. #808. Presented at: The 47th Annual Meeting of the Infectious Diseases Society of America. Oct. 29-Nov. 1, 2009. Philadelphia.