Merck promised the FDA reviewers it would market Gardasil with the message that sexual abstinence and pap smears are the only sure ways to prevent HPV infection and catch cancers. Its marketing campaign might include supporting sexual abstinence programs, the company has said.

Gardasil, which would be manufactured in suburban Philadelphia by Merck & Co. Inc., still needs final approval by the US Food and Drug Administration, but the agency typically takes its panels' advice.

Merck predicted Gardasil would prevent about 350,000 cases yearly of cervical cancer worldwide within two decades, when all girls vaccinated as infants will have entered high-risk adulthood. Currently an estimated 3,700 women in the United States, and 300,000 worldwide, die from cervical cancer a year.

More Than $1 Billion in Sales

Gardasil also might help alleviate Merck's own financial ailments from its recall and lawsuits over the pain reliever Vioxx and loss of patent-protected sales of the cholesterol drug Zocor. Wall Street analysts have predicted Gardasil sales will far surpass $1 billion a year by 2010, high for a vaccine.

"I love the world of vaccines," said Rick Haupt, executive director of medical affairs at Merck's vaccine division. "We're in the business of vaccines for now and the future, and this is a very important step."

The FDA's Vaccines & Related Biological Products Advisory Committee, after a daylong meeting in Gaithersburg, Md., unanimously recommended Gardasil for use in women and girls age 9 to 26. Merck has estimated that 374 million people a year eventually could be candidates for the vaccination.

Gardasil, designed to be administered in three low-dose shots over six months, works by preventing infection from two types of human papillomavirus, or HPV, that have been showed to cause 70 percent of cervical cancers. It is most effective in virgins or females previously unexposed to HPV, an extremely common virus thought to be present in 20 million people in any of its many strains, most of which resolve on their own.

Gardasil also blocks infection by two other HPV types linked primarily to genital warts.

World Without Cervical Cancer

A rival drugmaker, GlaxoSmithKline PLC, is working on its own HPV vaccine targeting a slightly different set of virus types. But its Cervarix is still in development and may not be submitted for FDA approval until next year, the company has said.

Merck promised the FDA reviewers it would market Gardasil with the message that sexual abstinence and pap smears are the only sure ways to prevent HPV infection and catch cancers. Its marketing campaign might include supporting sexual abstinence programs, the company has said.

"This vaccine is not a replacement for cervical cancer screening," said Eliav Barr, head of biological clinical research in West Point, Pa.

Side effects include fever and occasional soreness at the injection site. Merck reported five instances in which women taking Gardasil later had children with birth defects. But it argued, and FDA reviewers agreed, there was probably no connection to Gardasil because of the variation in defects and pregnancy periods.

A parade of health advocates -- many of them disclosing they had received Merck grants -- rose to urge the FDA advisers to endorse Gardasil.

"The FDA has an opportunity to move toward a world without cervical cancer," said Martha Nolan, vice president of the Society for Women's Health Research.

Backed by the groups, Merck asked the committee to endorse vaccination of boys age 9 to 15, too. Urging them not to wait for ongoing studies to end, it said evidence shows Gardasil can prevent some male cancers and may slow the spread of sexually transmitted HPV.

"By delaying three-plus years, we could have an additional 100,000 [cancer] cases that could have otherwise been avoided," Barr told the committee.

But panel members didn't vote on the request, calling the idea compelling but unproven.

Implementation Interventions

If approved by FDA officials, as expected, the next hurdle for Merck comes June 29, when vaccine experts at the Centers for Disease Control and Prevention are scheduled to consider whether to include Gardasil on its list of recommended vaccinations for children in the United States.

State and local officials are not obligated to follow the CDC but usually do, and sometimes even go further by mandating certain vaccines for school enrollment -- a huge boost for drug makers.

Some groups initially concerned the HPV vaccines would encourage sexual activity said they support the vaccine, as long as schools do not require it as a condition of enrollment.

Merck, which has taken great pains to assuage the groups' concerns, declined to say whether it thinks Gardasil should be mandatory but does support mandatory vaccinations in general.

"We are considering all kinds of interventions that could implement this vaccine, and under consideration are ways we can support states to drive implementation," Haupt said.

Blockbuster Drug?

Wall Street analysts have projected Gardasil sales could reach $140 million this year, $670 million next year and $1.9 billion by 2010.

One analyst, Steve Scala, of Cowen & Co. LLC, cautioned that the Gardasil sales projections may be high and said GlaxoSmithKline's vaccine still could prove to be better. Nonetheless, Scala called Gardasil a likely blockbuster drug that could provide Merck a needed boost.

Merck's global headquarters are in Whitehouse Station, NJ, but much of the Gardasil work would be handled by the company's marketing and vaccine operations centered at West Point and employing between 10,000 and 12,000.

The complex is the largest in the 60,000-employee company. It largely was spared from severe cuts in Merck's restructuring plan initiated last year.