Acyclovir -- a low-cost, generic drug used to treat herpes -- also might help control HIV in people living with both viruses, according to a study published Wednesday in the journal ell Host and Microbe, Reuters reports.
According to the study, acyclovir can help control HIV in infected individuals but only in tissues that also are infected with herpes. This finding might explain why some studies have shown that people taking acyclovir have lower HIV viral loads, while other studies have shown that taking the drug does not prevent HIV transmission.
Lead researcher Leonid Margolis of NIH's National Institute of Child Health and Human Development said that the herpes virus alters acyclovir into a form that can work against HIV. "If you suppress herpes, HIV also goes down," Margolis said. Acyclovir does not become active until it encounters the herpes virus, and the virus then completes a chemical reaction called phosphorylation, which turns the drug into an active compound.
According to Reuters, Margolis said several high-profile studies aimed at preventing HIV infection by treating patients for genital herpes failed because testing "acyclover against HIV in pure cell lines, it doesn't work." In addition, researchers in the prevention studies were trying to suppress herpes completely. "If you suppress herpes virus completely, there is nothing to phosphorylate," Margolis added. He also said that lower or more infrequent doses of the drug could be more effective but that this possibility will have to be tested.
Margolis said that he hopes the outcome of his team's study will help researchers find better ways to use acyclovir against HIV/AIDS and perhaps develop new products such as a microbicide. In addition, adding acyclovir to antiretroviral combination therapies could bolster the therapies, Margolis said. Duane Alexander, director of NICHD, said, "The findings open up promising new avenues of investigation in the fight against the AIDS virus." According to the study, people do not have to be living with the genital herpes virus, or herpes simplex-2, to benefit. Any herpes virus -- including the strains HHV6 and HHV7, which cause an almost universal childhood infection called roseola -- could produce the same effects, according to Reuters (Fox, Reuters, 9/10).
The study is available online.