Cervical Cancer Vaccine Shows Promise

Oct. 6, 2005 -- An experimental vaccine that targets viruses responsible for most cervical cancers will soon be sent to the FDA for review.

The vaccine is called Gardasil. It's made by Merck & Co. Merck spokeswoman Janet Skidmore tells WebMD that Merck will submit Gardasil for the FDA's review by the end of 2005. Merck is a WebMD sponsor.

In phase III clinical trials -- the last step before application for FDA review -- Gardasil was 100% effective against two forms of the human papillomavirus (HPV), according to a Merck news release.

Those two forms of HPV are HPV 16 and 18. They are transmitted through sex. Together, they cause about 70% of all cervical cancers. The CDC estimates that 20 million people are infected with HPV, and 6.2 million people in the U.S. get a new infection of HPV each year. Unfortunately most people will be unaware that they are infected as most will not have any symptoms.

Nearly 10,370 cases of invasive cervical cancer will be diagnosed and an estimated 3,710 American women will die from cervical cancer in 2005, predicts the American Cancer Society (ACS). However, HPV infection can be the cause of a much higher number of abnormalities, which can be discovered on routine Pap test screening.

The Pap test can screen for cervical abnormalities that may be cancerous or precancerous. The American Cancer Society recommends that screening starts three years after the start of vaginal intercourse and no later than the age of 21.

It is important to note that HPV infection and/ or an abnormal Pap test don't always indicate cancer. Most cases will resolve on their own, but it is important to follow up with a gynecologist for the necessary treatment to prevent the progression to invasive cervical cancer.

Results from Gardasil's phase III studies are due for presentation in San Francisco at the Infectious Diseases Society of America.

Not Total Protection

The vaccine doesn't prevent all cervical cancer. Some cervical cancers are caused by other factors.

The vaccine would likely target women who haven't been exposed to HPV. The most likely candidates would be young women prior to the onset of sexual activity.

"At this point, there is no data suggesting that the vaccine works on women who already have the infection," National Cancer Institute epidemiologist Allan Hildesheim, PhD, tells WebMD.

It's not yet known how long the protection lasts, and if booster vaccines could extend the protection, says Hildesheim.