Merck hopes to extend gardasil vaccine to men.

G ardasil, the vaccine that protects women from common strains of the human papillomavirus (HPV) responsible for about 70% of cervical cancers, has proved successful. According to the Centers for Disease Control and Prevention’s National Immunization Survey, about 25% of women have received the vaccine. Now Merck, the pharmaceutical giant that manufactures Gardasil, is looking to match that success in men. In a November press release, Merck announced completion of an initial study showing that Gardasil has a 90% effi cacy in preventing external genital lesions caused by HPV types 6, 11, 16, and 18 in men aged 16 – 26 years. On the basis of this latest study as well as earlier studies in younger boys, Merck plans to seek approval from the U.S. Food and Drug Administration for Gardasil use in males aged 9 – 26 years to prevent external genital lesions, including genital warts, according to Tracy Ogden, a company spokesperson. “This is the fi rst clinical trial to demonstrate that a vaccine directed against HPV is effi cacious in preventing both infection and lesions in men,” said Anna Giuliano, M.D. , who led the Merck study at the H. Lee Moffi tt Cancer Center in Tampa, Fla. Although the study did not produce data on whether Gardasil can protect men from penile, perineal, or anal cancers, Giuliano said that there is defi nitive evidence that HPV causes these cancers in men. According to the National Cancer Institute, more than 1,200 new cases of penile cancer and about 2,000 new cases of anal cancer are diagnosed in men each year in the U.S. Between 80% and 90% of anal canal cancer cases are the result of HPV — usually HPV-16 — as are about 40% of all penile cancers, Giuliano said. Moreover, because HPV is the most common sexually transmitted infection in the United States among men and women, with about 6.2 million new persons infected each year, reducing incidence of HPV in the general population could affect disease transmission as well as cancer rates. “There’s pretty good evidence that men are a reservoir for HPV and are vectors for it,” said James Turner, M.D., professor of clinical internal medicine at the University of Virginia and chair of the Vaccine Preventable Disease Committee for the American College Health Association. “Protection makes sense, particularly if you can vaccinate boys before they become sexually active.” If the FDA approves the vaccine for males, the CDC’s Advisory Committee on Immunization Practices (ACIP) will also review the data and recommend how the vaccine should be used. The ACIP recommendation will be important because it serves as a guideline for primary care providers. “Certainly if the ACIP recommends the HPV vaccine at age 11, it will be adopted by pediatricians and family practitioners,” Turner said. “They’ll recommend it when families come in.” For women, the ACIP recommended that the Gardasil vaccine target girls aged 9 – 11 years, with catch-up vaccination recommended between ages 12 and 26 years. Merck hopes that the same will be true for males. “The goal is for boys to be protected from something that can be prevented,” Ogden said. “And the incidence of genital lesions is high for boys.”