Experimental Cervical Cancer Vaccine Shows Promise

Trial results indicate it is 100 percent effective in preventing disease

THURSDAY, Oct. 6, 2005 (HealthDay News) -- The first large study of an experimental cervical cancer vaccine called Gardasil showed it prevented 100 percent of cervical pre-cancers, and noninvasive cervical cancers caused by human papillomavirus (HPV).

Based on these findings Merck and Co., the vaccine's maker, is planning to seek U.S. Food and Drug Administration approval for the vaccine before the end of the year.

HPV infection has been identified as the cause of cervical cancer, pre-cancers, benign cervical lesions and genital warts.

Cervical cancer causes an estimated 290,000 deaths worldwide each year. In the United States, some 10,400 new cases will be diagnosed this year, and 3,700 women will die from the disease.

An estimated 20 million men and women in the United States are infected with HPV. For most, HPV shows no symptoms and goes away on its own. However, HPV can lead to cervical cancer in some women. The virus is also associated with abnormal Pap test results.

According to Merck, the trial is part of the ongoing phase III program for Gardasil, which includes more than 25,000 people in 33 countries. In this part of the trial, 12,167 women from 13 countries participated.

The findings were to be reported Friday at the Infectious Disease Society of America annual meeting, in San Francisco.

"These are the first pivotal data to show that vaccination with Gardasil reduced HPV 16 and 18-related cervical pre-cancer and non-invasive cervical cancer," Laura Koutsky, a principal investigator in the HPV research group at the University of Washington, Seattle, said in a prepared statement.

In the study, women 16 to 26 years of age were randomly selected to receive a three-dose regimen of either Gardasil or a placebo over six months. The researchers report that none of the women who received the vaccine went on to developed either pre-cancer or invasive cervical cancer associated with HPV types 16 and 18.

Over two years of follow-up, the vaccine reduced the risk of cervical cancer by 97 percent, the researchers reported. There was one case of cervical cancer in the vaccinated group compared with 36 cases among women who received placebo.

One expert thinks the results are impressive, but more data is needed before the vaccine could be given to the public.

"It's extremely exciting," said Dr. David A Fishman, director of the New York University Cancer Institute's Gynecologic Oncology, Cancer Prevention and Early Detection program, and a professor of medicine at NYU School of Medicine. "But I am cautiously optimistic until this has undergone peer review," he added.

Anything that would prevent women from getting cervical cancer is critically important, Fishman said. "If there were a vaccine that was 90 percent effective it would be wonderful not only in the U.S. but globally," he said. "More women die globally from cervical cancer than in the U.S."

"If this is validated by the FDA, this would be tremendous," Fishman said. "My hope is that this would be validated."

Another expert agrees with Fishman that peer review and FDA approval are necessary before the real effectiveness of the vaccine is known.

"The bottom line is that this is another exciting study which points to the likely availability of a vaccine for HPV, but it is critical the data be peer-reviewed and published," Debbie L. Saslow, the director of breast and gynecological cancers at the American Cancer Society, said in a prepared statement.

"If and when the FDA approves the vaccine, federal advisory groups will decide whether to recommend the vaccine and if so under what conditions," she added. "Until those issues are resolved, the society's guidelines will not change. We are reviewing the data with the intent to have formal recommendations regarding screening of women who have been vaccinated and will continue to actively participate with other groups responsible for making any recommendations for use of the vaccine."

More information

The American Cancer Society can tell you more about cervical cancer.

SOURCES: David A Fishman, M.D., director, New York University Cancer Institute's Gynecologic Oncology, Cancer Prevention and Early Detection program, and professor of medicine, NYU School of Medicine, New York City; Oct. 6, 2005, press release, Merck & Co., Inc., Whitehouse Station, N.J.; press release, American Cancer Society, Atlanta
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