HPV Vaccine Approved for Anal Cancer
On December 22, 2010, the U.S. Food and Drug Administration
(FDA) approved the use of Merck's quadrivalent human
papillomavirus (HPV) vaccine, Gardasil, for prevention
of anal cancer in men and women age 9-26 years.
The vaccine -- which targets high-risk HPV types
6, 11, 16, and 18 -- was previously approved for
prevention of cervical cancer in young women.
papillomavirus, commonly transmitted via sexual activity,
causes excessive growth of epithelial cells. Some types (for
example 6 and 11) cause genital warts, while others (especially
16 and 18) can cause cervical or anal cancer.
HIV positive people are
at greater risk for HPV infection, tend to carry more HPV
types, clear infection less easily, and are more likely to
develop pre-cancerous cell changes in the genital-anal region
caused by the virus. Over time, these changes -- known as
cervical or anal intraepithelial neoplasia (CIN or AIN) and
squamous intraepithelial lesions (SIL) -- can progress to
cancer if not detected and treated.
Invasive cervical cancer is classified as an AIDS-defining
condition. Anal cancer, caused by the same high-risk HPV types,
has become more common as people with HIV live longer thanks
to effective antiretroviral therapy. It is not classified
as an AIDS-related condition, but many experts think it should
The studies supporting Gardasil's approval for anal cancer
prevention were conducted in HIV negative people, but ongoing
research indicates that the vaccine is also likely to be effective
in HIV positive individuals, and physicians may offer it for
this population. Gardasil is most effective when administered
to adolescents or young adults, before they acquire HPV via
Below is the text of an FDA press
release describing the new indication.
Gardasil Approved to Prevent Anal Cancer
22, 2010 -- The U.S. Food and Drug Administration today approved
the vaccine Gardasil for the prevention of anal cancer and
associated precancerous lesions due to human papillomavirus
(HPV) types 6, 11, 16, and 18 in people ages 9 through 26
is already approved for the same age population for the prevention
of cervical, vulvar, and vaginal cancer and the associated
precancerous lesions caused by HPV types 6, 11, 16, and 18
in females. It is also approved for the prevention of genital
warts caused by types 6 and 11 in both males and females.
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," said Karen Midthun, MD,
director of the FDA's Center for Biologics Evaluation and
anal cancer is uncommon in the general population, the incidence
is increasing. HPV is associated with approximately 90 percent
of anal cancer. The American Cancer Society estimates that
about 5,300 people are diagnosed with anal cancer each year
in the United States, with more women diagnosed than men.
Gardasil's ability to prevent anal cancer and the associated
precancerous lesions [anal intraepithelial neoplasia (AIN)
grades 1, 2, and 3] caused by anal HPV-16/18 infection was
studied in a randomized, controlled trial of men who self-identified
as having sex with men (MSM). This population was studied
because it has the highest incidence of anal cancer. At the
end of the study period, Gardasil was shown to be 78 percent
effective in the prevention of HPV 16- and 18-related AIN.
Because anal cancer is the same disease in both males and
females, the effectiveness data was used to support the indication
in females as well.
Gardasil will not prevent the development of anal precancerous
lesions associated with HPV infections already present at
the time of vaccination. For all of the indications for use
approved by the FDA, Gardasil's full potential for benefit
is obtained by those who are vaccinated prior to becoming
infected with the HPV strains contained in the vaccine.
recommended for anal cancer screening by their health care
provider should not discontinue screening after receiving
As of May 31, 2010, more than 65 million doses of Gardasil
had been distributed worldwide, since its approval in 2006
according to the manufacturer, Merck and Co. Inc, of Whitehouse
Station, N.J. The most commonly reported adverse events include
fainting, 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. This can be
prevented by keeping the vaccinated person seated for up to
15 minutes after vaccination. This observation period is also
recommended to watch for severe allergic reactions, which
can occur after any immunization.
Food and Drug Administration. FDA: Gardasil approved to prevent
anal cancer. Press release. December 22, 2010.
US FDA Approves New Indication for Merck's HPV Vaccine, Gardasil.
Press release. December 22, 2010.