Drug doesn't cut HIV risk

In another setback for AIDS research, Seattle scientists reported Monday that use of the drug acyclovir to treat people with genital herpes did not lower their risk of contracting HIV.

The findings tempered the hope that herpes medications might provide a cheap and easy way to slash transmission of HIV around the world.

"We were surprised and disappointed," said Dr. Connie Celum, the University of Washington researcher who led the study of more than 3,000 herpes-infected people on three continents.

Infection with herpes simplex virus 2, the cause of most genital herpes, can double or even triple a person's odds of contracting HIV. One of the most common sexually transmitted diseases worldwide, herpes often leads to recurring outbreaks of genital sores that are believed to provide a route for HIV to slip into the body.

In the United States, about one of every five people is infected with the herpes virus, many of whom don't know it. In parts of Africa and Latin America where AIDS is rampant, the prevalence of herpes infections is twice as high, Celum said.

So scientists had been optimistic that acyclovir, a generic drug that reduces herpes outbreaks, also would reduce the odds of HIV infection.

"But the answer was no. It doesn't help," said Rowena Johnston, vice president for research for the nonprofit Foundation for AIDS Research. Johnston was not involved in the study.

Of those who received acyclovir in the clinical trial, 3.9 percent, or 75 people, contracted HIV. The result was statistically indistinguishable from the control group that got placebo pills: 3.3 percent, or 64 people, became infected with HIV.

The bad news comes shortly after a major AIDS-vaccine trial, also led by Seattle scientists, was halted when data hinted that the experimental drug may have actually raised the risk of contracting HIV. Two large studies of microbicides, gels that women insert in their vaginas to protect against HIV infections, also were stopped after it appeared the gels might increase vulnerability to the deadly virus.

Also on Monday, another group of researchers reported that circumcision, which has been shown to reduce men's risk of HIV infection, provides no benefit to the men's female partners.

"We could use some good news," Johnston said from the Fifteenth Conference on Retroviruses and Opportunistic Infections in Boston, where the Seattle group presented the herpes results.

Some experts are urging a return to basics in HIV prevention, including education, abstinence campaigns and wider promotion of condom use. Others say researchers may have pushed too fast to test potentially lifesaving vaccines or drugs, skipping laboratory studies that could have pointed up flaws, Johnston said.

"We may be running the risk of losing the public's faith that scientists can come up with an answer," she said.

Celum said the herpes-test study will help guide future research.

For example, it may be possible that inflammation lingers after a herpes outbreak — even outbreaks that aren't noticeable to the infected person, Celum said. HIV can easily attach to immune-system cells, called T-cells, that are present in inflamed tissues.

"It may be there's more to it than just the herpes virus being present," she said. "Maybe the immune response to the virus in the genital tract is important."

Celum and her co-workers have a $30 million grant from the Bill & Melinda Gates Foundation to explore another aspect of the herpes-HIV link: the fact that people who are infected with both viruses are more likely to transmit HIV to their partners.

The researchers are working with monogamous couples, one of whom is infected with both viruses, and one of whom has neither, to see if acyclovir treatment of the infected partner will protect the uninfected partner from contracting HIV.

The Seattle scientists also are conducting a small trial to see if higher doses of acyclovir will work better to cut down herpes outbreaks and viral shedding. The herpes-HIV trial used the standard dosage of 400 mg, twice a day.

Launched in 2003, the study was conducted in Seattle, New York, San Francisco, Peru, South Africa, Zambia and Zimbabwe. Participants in the United States and South America were herpes-infected men who have sex with men. Volunteers in Africa were herpes-infected women.

Sandi Doughton: 206-464-2491 or sdoughton@seattletimes.com/\