March 17, 2015
1 min read

Valacyclovir reduces HIV viral load in HSV-2 seronegative patients

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New data from NIH researchers indicate that valacyclovir decreases HIV plasma viral load among patients who are seronegative for herpes simplex virus-2.

According to the report in Clinical Infectious Diseases, previous data showed that acyclovir and its prodrug valacyclovir lower the HIV viral load among patients coinfected with HIV and HSV-2, but this is the first study in humans that suggests it would have the same effect in patients without HSV-2. Recently, the researchers found that acyclovir suppressed HIV in tissues that were not infected with HSV-2, but coinfected with other human herpesviruses.

“These findings are very encouraging,” Leonid Margolis, PhD, head of the section on intercellular interactions at the NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development, said in a press release. “If valacyclovir’s effectiveness against HIV can be confirmed in a larger cohort, it could be added to the mix of drugs used to suppress the virus, and might prove especially helpful in cases in which HIV has developed resistance to other drugs.”

The study included 18 patients with HIV who were HSV-2 seronegative. They were randomly assigned to two groups. In group A, patients received valacyclovir, 500 mg twice daily, for 12 weeks, followed by 2 weeks of no treatment and then 12 weeks of placebo. In group B, patients received placebo for 12 weeks, followed by 2 weeks of no treatment, then 12 weeks of valacyclovir, 500 mg twice daily. Blood samples were collected at weeks 11, 12, 14, 25 and 26 and measured for HIV viral load.

The median viral load before valacyclovir treatment was 4.09 log10 copies/mL and the medial viral load after treatment was 3.77 log10 copies/mL, a reduction of 0.37 log10 copies/mL (95% CI, – 0.62 to – 0.11)). In a genetic analysis, the researchers found the patients’ HIV did not develop resistance to valacyclovir.

“We cannot discount the possibility that a more pronounced evolution of specific HIV acyclovir resistance mutations might have been observed following a longer period of valacyclovir monotherapy,” the researchers wrote. – by Emily Shafer

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