Thursday, November 21, 2002

BY REBECCA GOLDSMITH
Star-Ledger Staff

Researchers have developed a powerful weapon in the fight against cervical cancer -- a vaccine that proved 100 percent effective in early tests.

The experimental vaccine blocks the virus that causes the disease and could go a long way in curtailing the second most deadly cancer in women, doctors said.

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The vaccine, made by Merck & Co. of Whitehouse Station, would not reverse the course of existing cancers, but could prevent new cases from developing. It also holds great promise for protecting women from contracting genital warts.

Before the vaccine can be marketed, however, the company must show it is free of side effects and effective with large numbers of people. That process can take several years.

An article in today's New England Journal of Medicine reporting progress in a four-year study showed the human papillomavirus did not infect any of the 768 women who received the vaccine. Of 765 who got placebo injections, 41 contracted infections and nine developed precancerous tissue.

"It's a beautiful theoretical study that is very promising," said Christopher Crum, a pathologist at Brigham and Women's Hospital in Boston who wrote an editorial that accompanies the report. "They have apparently succeeded in preventing the first two steps in the pathway to cervical cancer."

Almost all cases of cervical cancer are caused by the human papillomavirus, a sexually transmitted disease that infects about half of all adults. The virus can cause genital warts in addition to cervical cancer.

Merck, which has been funding research in the vaccine for the past nine years, is now engaged in later-stage trials involving tens of thousands of women around the world, said spokeswoman Janet Skidmore.

"We're really very optimistic about this vaccine candidate," Skidmore said. "We do hope that if all goes well in the next few years there may be a vaccine in the next five years."

The experimental drug protects against four types of the virus, which account for 70 percent of the cases of cervical cancers and 90 percent of the cases of genital warts, Skidmore said. There are more than 60 types of the virus, but fewer than 20 are connected to cancer.

Cervical cancer is the second leading cause of cancer-related deaths in women, next to breast cancer. In the United States, the disease develops in about 15,000 women and kills about one-third. Worldwide, more than 450,000 cases are diagnosed each year, resulting in 250,000 deaths.

Many more women develop genital warts.

"The most important part is the focus on cervical cancer, but if you're a person who has genital warts, they're unsightly, they're very uncomfortable, and they're embarrassing," Skidmore said.

Most cases of cervical cancer are now detected by annual pap smear tests. The vaccine would not necessarily replace the tests, but it could alter the way women are screened for the virus, doctors said.

"One can see the pap smear is not going to go away in the near future," Crum said. A vaccine used in combination with a screening technique could lead to widespread changes in women's medical regimens.

The vaccine would be administered in three doses over six months. The target market for the vaccine would be girls who are not yet sexually active.

Such a method would particularly benefit the developing world, where women do not have easy access to annual pap smears, good laboratories or follow-up care, said Allan Hildesheim, senior investigator for the division of cancer epidemiology and genetics at the National Cancer Institute. These women are far more likely to end up dying of cervical cancer, which is easily treated if caught early.

"It's terrific news. If the results of the study are shown to be correct, this is only the second vaccine after the hepatitis B vaccine that can prevent a cancer," he said.

Wilberto Nieves, who specializes in gynecological cancers at the Cancer Institute of New Jersey in New Brunswick, said cervical cancer still kills at least 4,000 American women each year. Some of them have their annual pap smear and still develop the cancer.

"You can envision in the future that you can implement vaccination programs, and we will see a reduction in the death rate," he said.

Staff writer Carol Ann Campbell contributed to this article.