|Herpes Drug Helps Control HIV
February 22, 2007
by Roxanne Khamsi
A drug designed to combat genital herpes can also reduce levels of HIV in the blood by 70%, a small trial in Africa has revealed. The herpes medication, valacyclovir, also appears to reduce levels of HIV in the genital tract.
The researchers behind the study suggest that valacyclovir, and other herpes drugs, might dramatically reduce the spread of HIV. Philippe Mayaud of the London School of Hygiene and Tropical Medicine, UK, and colleagues recruited 140 women infected with both HIV and herpes in the West African nation of Burkina Faso.
All of the women had high levels of CD4 immune cells, meaning they were still relatively healthy and ineligible to receive antiretroviral HIV drugs under World Health Organization guidelines.
In addition, none of the women had visible symptoms of herpes so they would not normally be given herpes medication such as valacyclovir.
The researchers gave half of the women valacyclovir and the other half women placebo pills. At the end of three months, copies of HIV in those who received valacyclovir had dropped from 25,000 copies per millilitre of blood to 8000 per millilitre – a 70% reduction.
This is the same effect one would expect if the women had been given an anti-HIV drug such as Zidovudine (AZT), according to Mayaud. Levels of HIV found in the blood of women who received the placebo, by comparison, had increased slightly on average.
Because all of the women were healthy to start with, there was no difference in symptoms during the 3-month period. But Mayaud says that such a dramatic drop in virus particles could potentially delay the onset of AIDS.
"It's important to know if the effect is sustained over a long period," he adds, stressing the need for long-term studies of valacyclovir's effect on HIV infection.
Researchers believe that valacyclovir indirectly reduces HIV infection by decreasing copies of the herpes virus. They note that untreated herpes can cause lesions in the genital region, which subsequently attract a type of immune cell that harbours HIV.
Mayaud points out that the women who received valacyclovir also had half as many copies of HIV in their genital tracts compared to those who received the placebo. This also suggests that valacyclovir has the potential to reduce the spread of HIV, he says.
In Africa, between five and nine out of 10 HIV-infected patients are also infected with herpes. In Europe, the figure is between three and seven out of 10.
Lawrence Corey at the University of Washington in Seattle, Washington, US, says this is good reason to explore herpes drugs as a treatment for HIV. "Because so many people in the world are co-infected we should spend more time on that," he told New Scientist.
Mayaud adds that some herpes drugs, such as acyclovir, cost just $40 per year while the triple-drug regimens normally used to lower HIV levels in patients cost anywhere from $150 to $300 per year.
However, it remains unclear whether valacyclovir would offer an additional benefit if taken with a triple-drug HIV treatment.
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