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Bivalent vaccine had cross-protective effect against numerous HPV types
Wheeler CM. Lancet Oncol. 2011;doi:10.1016/S1470-2045(11)70287-X.
Final data from the PATRICIA study indicates the bivalent HPV vaccine has cross-protective efficacy against HPV-33, HPV-31, HPV-45 and HPV-51 types.
Researchers involved in the PATRICIA study conducted several sub-analyses to draw more conclusions from the study data.
In this analysis, the researchers evaluated if the bivalent HPV vaccine (Cervarix, GlaxoSmithKline) provided protection from any addition HPV types outside of HPV-16 and HPV-18, for which the vaccine was designed.
They examined data in three groups: the according-to-protocol cohort for efficacy; the total vaccinated cohort (TVC); and the TVC HPV-naive cohort, which had no exposure to HPV types at baseline.
Data indicated the vaccine provided consistent protection against cervical intraepithelial neoplasia grade 2 or higher for HPV types 33, 31, 45 and 51.
When the researchers isolated the data to exclude anyone co-infected with HPV types 16 and 18, they found the vaccine’s efficacy against HPV-33 still existed in all cohorts. Protection against HPV-31 still existed in the according-to-protocol cohort and the TVC-naive cohort.
Overall protection against a series of 12 non-vaccine HPV types was 46.8% for the according-to-protocol cohort, 56.2% for the TVC-naive cohort and 34.2% for the TVC cohort.
“The substantial cross-protection Cervarix provides against some other oncogenic types, especially against HPV-31/-33/-45, increases its effectiveness for prevention of precancer and cancer, beyond the more limited cross-protection reported for Gardasil,” Mark Schiffman, MD, and Sholom Wacholder, PhD, senior investigators with the NCI’s Division of Cancer Epidemiology and Genetics, wrote in an accompanying editorial.