Gardasil targets four strains of human papillomavirus, commonly called HPV. The vaccine already has FDA approval for use in females ages 9 to 26. But HPV isn't restricted to girls and women.
Males can carry HPV and transmit it sexually to their partners. HPV can also cause genital warts and penile and anal cancer in men. Those cancers are rarer than cervical cancer, which HPV can cause in women.
Gardasil is up for FDA consideration only as a way to prevent genital warts, not to prevent cancer or to curb transmission of the HPV virus to women.
The FDA advisory committee will review three studies of Gardasil that together included more than 5,000 males ages 9 to 26 in various countries including the U.S. Participants got three shots of either Gardasil or a placebo over six months. They also got checkups and tests for HPV infection.
Gardasil was 89% effective in preventing genital warts. The vaccine was less effective in participants who had already been exposed to HPV.
No serious side effects were seen, according to information posted on the FDA's web site.
The most commonly reported adverse events were fever and headache. Injection site reactions were more common with Gardasil than with the placebo. Most of those reactions were mild to moderate in intensity, Gardasil's maker, the drug company Merck, states in a document posted on the FDA's web site.
Gardasil is licensed for use in males in many countries, and there haven't been any red flags raised about the vaccine's safety in the limited number of international safety reports that have been done, FDA documents state. But those FDA documents say that post-marketing surveillance and studies will be "essential" if Gardasil is approved for males. Merck's post-marketing plans will be discussed at Wednesday's meeting.
There wasn't enough data to assess Gardasil for preventing other conditions since those conditions were so rare, the FDA notes.
The FDA advisory committee doesn't have the final word on approving Gardasil for boys; that's the FDA's job. The FDA often follows the recommendations of its advisory committees, but it isn't required to do so.