Gardasil Approved to Target More Cancers

FDA Expands HPV Vaccine Gardasil to Prevent Certain Cancers of the Vulva and Vagina
By Miranda Hitti
WebMD Health News
Reviewed by Louise Chang, MD

Sept. 12, 2008 -- The FDA today announced that the vaccine Gardasil may be used to prevent some cancers of the vulva and vagina in girls and women ages 9-26.

Gardasil is already approved to help prevent a leading cause of cervical cancer in women of that same age range.

Gardasil targets four strains of the human papillomavirus (HPV) that cause most cases of cervical cancer. Two of those HPV strains can also cause some vulvar and vaginal cancers.

"There is now strong evidence showing that this vaccine can help prevent vulvar and vaginal cancers due to the same viruses for which it also helps protect against cervical cancer," Jesse L. Goodman, MD, MPH, director of the FDA's Center for Biologics Evaluation and Research, says in a news release.

"While vulvar and vaginal cancers are rare, the opportunity to help prevent them is potentially an important additional benefit from immunization against HPV," Goodman says.

Gardasil and HPV

Gardasil first gained FDA approval in 2006 for use in girls and women aged 9-26 to help prevent cervical cancer, precancerous genital lesions, and genital warts.

The CDC recommends Gardasil for all girls aged 11-12. Girls can get Gardasil when they're as young as 9. If they miss vaccination at ages 11-12, they can get vaccinated by age 26.

To be most effective, Gardasil should be given before a girl becomes sexually active. There are more than 100 strains of the HPV virus, and more than 30 of those strains can be spread through sex. According to the CDC, HPV is the most common sexually transmitted infection in the U.S, with some 6 million Americans becoming infected with genital HPV each year.

HPV doesn't always cause cervical cancer. For most women, the body's own defense system will clear HPV, preventing serious health problems. But some HPV types can cause abnormal cell growth in areas of the cervix, vagina, vulva, and other areas that years later may turn into cancer.

Men can also carry HPV. But Gardasil isn't approved for use in men.

Gardasil vs. Vulvar, Vaginal Cancers

The FDA approved Gardasil to help prevent vulvar and vaginal cancers based on a follow-up report from Merck, the drug company that makes Gardasil, on more than 15,000 participants from Gardasil's original studies.

Merck followed those participants for two extra years and found that Gardasil was highly effective at preventing precancerous vulvar and vaginal growths related to HPV types 16 and 18, which the vaccine targets.

But Gardasil only showed that benefit in women who hadn't been infected with HPV before getting Gardasil.

"To receive Gardasil's full potential for benefit, it is important to be vaccinated prior to becoming infected with the HPV strains contained in the vaccine," states an FDA news release.

Gardasil's label has been revised to note that current information is insufficient to support use beyond age 26, the current FDA-approved age. Also, new information has been added showing that Gardasil doesn't protect against diseases caused by HPV types not contained in the vaccine.

No vaccine is 100% effective, and Gardasil doesn't protect against HPV infections that a woman may already have at the time of vaccination. So the FDA recommends that all women get regular Pap tests, even after they have been vaccinated. Routine Pap screening remains critically important to detect precancerous changes, which would allow treatment before cancer develops.

The FDA notes that since Gardasil was approved, most reported adverse events haven't been serious. The most common reports have been of pain at the injection site, headache, nausea, and fever.

Fainting is common after injections and vaccinations, especially in adolescents. Falls after fainting may sometimes cause serious injuries, such as head injuries, which can be prevented with simple steps, such as keeping the vaccinated person seated for up to 15 minutes after vaccination. The FDA recommends that observation period to watch for severe allergic reactions, which can occur after any immunization.