Experiment to treat genital herpes produces no protection

A once-promising experiment to see if treating genital herpes with a common drug could dramatically reduce susceptibility to HIV infection has found no protection whatsoever -- a shocking setback for researchers hoping to find a pill that would slow the spread of the AIDS epidemic.

Results of the long-awaited study, which included gay men in San Francisco, Seattle, New York and Peru, as well as women in Africa, were released here Monday at the 15th annual Retrovirus conference, the premiere annual scientific meeting of AIDS researchers.

Nearly 20 years of various studies on herpes had shown that herpes infection nearly tripled the risk of contracting HIV. The assumption was simple -- use acyclovir, a proven anti-herpes drug, to knock down that infection, and the odds of avoiding HIV would dramatically improve -- by at least 50 percent, on par with the prevention benefit now attributed to male circumcision.

Results of the study were shielded from researchers and subjects alike until the study period was completed, but when statisticians tabulated their data, the answer was certain: Those who took acyclovir to suppress their herpes infections acquired HIV infections at exactly the same rate as those who took a placebo.

"This was a huge setback for HIV prevention," said Dr. Sharon Hillier, a researcher at the Magee-Women's Research Institute at the University of Pittsburgh.

Scientists had a lot of reasons to think that the results of this study could be as exciting as the findings in 2005 and 2006 that adult male circumcision -- the surgical removal of the foreskin -- reduced by as much as 60 percent the risk that those man would contract HIV.

"Many people thought this was going to be a slam dunk," said Dr. Connie Celum, the University of Washington professor who led the study since it was approved in 2004.

"It was definitely disappointing, but it was also very clear," she said of the result.

Now the long and difficult task is to find out why it did not work, and what might be done to come up with different outcome.

The theory that immediately jumped to the top of the list of possibilities is that suppressing herpes was not enough. Although acyclovir is a very effective treatment for herpes simplex 2, it does not eradicate it, and many of those who take it will continue to have occasional flareups of genital ulcers.

Dr. Kevin DeCock, director of the Department of HIV/AIDS at the World Health Organization, said he was disappointed but not entirely surprised by the results of the study. "What we really need," he said, "is a herpes vaccine."
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