WEDNESDAY, Oct. 26 (HealthDay News) -- Quadrivalent human papillomavirus (qHPV) vaccine is safe and efficacious against anal intraepithelial neoplasia in men who have sex with men, according to a study published in the Oct. 27 issue of the New England Journal of Medicine.
Joel M. Palefsky, M.D., from the University of California at San Francisco, and colleagues investigated the safety and efficacy of qHPV vaccine in preventing HPV 6-, 11-, 16-, or 18-related anal intraepithelial neoplasia in 602 healthy men who have sex with men (aged 16 to 26 years). Participants were randomized to receive either qHPV or placebo. Prevention of HPV-related anal intraepithelial neoplasia or anal cancer was the primary efficacy objective. Efficacy was measured in intention-to-treat and per-protocol efficacy populations.
The investigators found that the efficacies of qHPV vaccine against HPV 6-, 11-, 16-, or 18-related anal intraepithelial neoplasia were 50.3 and 77.5 percent in the intention-to-treat and per-protocol efficacy populations, respectively. Efficacies against any type of HPV-associated intraepithelial neoplasia were 25.7 and 54.9 percent, respectively. The rates of anal intraepithelial neoplasia per 100 person-years were lower in the vaccine versus placebo group (13.0 versus 17.5 in the intention-to-treat population; 4.0 versus 8.9 in the per-protocol efficacy population). The rates of grade 2 or 3 anal intraepithelial neoplasia and persistent anal infection were reduced by 54.2 and 59.4 percent, respectively, in the intention-to-treat population, and by 74.9 and 94.9 percent, respectively, in the per-protocol efficacy population. No vaccine-related adverse events occurred.
"Use of the qHPV vaccine reduced the rates of anal intraepithelial neoplasia, including of grade 2 or 3, among men who have sex with men," the authors write.
Several authors disclosed financial relationships with pharmaceutical companies, including Merck, which partially funded the study.