November 13, 2008
The human papillomavirus (HPV) vaccine Gardasil effectively prevents genital warts in males, according to a study to be presented today at the European Research Organization on Genital Infection and Neoplasia International Multidisciplinary Conference in Nice, France.
Gardasil targets two types of the STD linked to 70 percent of cervical cancers as well as two that cause most genital warts. It is approved for use in US females ages nine to 26. While males can spread HPV, the vaccine was not licensed for them because no evidence was submitted during the approval process that Gardasil prevented disease in men. There is still no evidence Gardasil prevents penile or other HPV-caused cancers in men or the spread of HPV from men to women.
Funded by Gardasil's maker, Merck & Co., the study involved about 4,000 males ages 16-26 in nearly 20 countries, including more than 1,000 males in the United States. It found Gardasil was 90 percent effective in preventing genital warts, with just 15 cases of persistent infection in a vaccinated group of males compared to 101 cases in a group given a placebo vaccine.
The study's results are likely to boost a plan by Merck to seek Food and Drug Administration approval later this year to begin marketing Gardasil to boys, experts say.
"This opens the door to a wonderful opportunity to prevent illness," said Anna Giuliano, an epidemiologist at the H. Lee Moffitt Cancer Center in Tampa who worked on the study.
Dr. Lauri Markowitz, an HPV expert at CDC, said government officials have anticipated this interim analysis from Merck and are eager to see any additional information on Gardasil's effect on precancerous lesions.
"It's obviously encouraging data but the policy makers will be looking at a variety of different issues," including cost-effectiveness if used in males, Markowitz said. Gardasil, which is given in three doses over a six-month period, costs about $375.