A Food and Drug Administration advisory committee Wednesday recommended that the agency extend approval of the human papillomavirus (HPV) vaccine Gardasil for protection against anal cancer in males and females ages 9 through 26. The agency is not required to follow the recommendations of its advisory committees, but it generally does so.
Anal cancer is relatively uncommon, striking about 5,000 Americans each year. About 90% of cases are thought to be caused by HPV. Gardasil protects against four of the most common strains of HPV. It is already licensed for protection against cervical cancer in women and against genital warts in both sexes ages 9 to 26.
The new indication was based primarily on a clinical trial conducted among 4,065 men, 602 of them gay. Patients were randomly assigned to receive either three doses of the vaccine or a placebo. After 36 months, 3% of the gay males receiving the vaccine developed anal cancer or anal intraepithelial neoplasia, a precursor of anal cancer. In contrast, 12% of the placebo group developed one of the conditions. Although the study group's ages ranged from 16 to 26, the panel concluded that the results could be extrapolated to boys as young as 9.
According to the Centers for Disease Control and Prevention, as of Sept. 30 there were 17,160 reports of adverse events associated with Gardisil shots, 92% of them nonserious, including fainting, pain and swelling at the injection site. The agency concluded that there was no evidence to suggest that more serious events were linked to the vaccinations.