Gardasil is now approved as a vaccine for preventing anal cancer and associated precancerous lesions due to human papillomavirus (HPV) types 6, 11, 16, and 18, in males and females from 9 to 26 years old, said the The US Food and Drug Administration on Wednesday.
Human papillomavirus (HPV) is a sexually transmitted infection that usually causes genital warts, but it can also cause several cancers such as cervical cancer in women and anal cancer in both men and women, and precancerous lesions.
Director of the agency’s Center for Biologics Evaluation and Research, Dr Karen Midthun, told the press that:
“Treatment for anal cancer is challenging; the use of Gardasil as a method of prevention is important as it may result in fewer diagnoses and the subsequent surgery, radiation or chemotherapy that individuals need to endure.”
In 2008, the FDA approved Gardasil, as a vaccine to prevent cervical, vulvular and vaginal cancer and associated precancerous lesions caused by HPV types 6, 11, 16 and 18 in girls and women from age 9 to 26 years.
The vaccine, made by Merck and Co. Inc. of New Jersey, is also approved for the prevention of genital warts caused by HPV types 6 and 11 in both males and females.
Anal cancer is not common in the general population. According to the American Cancer Society, about 5,300 Americans are diagnosed with the disease each year, with more cases in women than in men.
However, the incidence of anal cancer is rising, and HPV is thought to play a role in 90 per cent of cases, said the FDA.
The agency stressed that Gardasil will not prevent the development of HPV-related precancerous lesions if the person is already infected with the virus when they receive the vaccine.
They also said if your doctor or health care provider has recommended you go for screening for anal cancer, you should still go for screening if you receive Gardasil.
At the last count, in May this year, more than 65 million doses of Gardasil have been distributed worldwide since its approval in 2006, said Merck.
The most commonly reported side effects include: fainting, pain at the injection site, nausea, headache, and fever.
It is not uncommon for people, especially teenagers, to faint when they receive injections and vaccinations, and the FDA warns that in such cases people can fall and hurt themselves, such as bang their heads, so they urge health providers to keep the patient seated for up to 15 minutes after they have received their vaccination. This is also a good time to look out for allergic reactions, which can sometimes happen with any vaccination, they added.
Prior to giving approval, the FDA reviewed evidence on Gardasil’s ability to prevent anal cancer and associated precancerous lesions (anal intraepithelial neoplasia (AIN) grades 1, 2, and 3) caused by anal infection of HPV types 16 and 18.
The evidence came from a randomized controlled trial of men who said they had sex with men (MSM), a group that has the highest incidence of anal cancer.
The trial showed that Gardasil was 78 per cent effective in preventing AIN lesions linked to HPV types 16 and 18, and because it is the same disease in men and women, this result was considered sufficient evidence that the vaccination would be equally effective in protecting women and girls, said the FDA.
Source: FDA (news release 22-Dec-2010).
Written by: Catharine Paddock, PhD