The herpes simplex virus 2 drug Valtrex (valacyclovir) reduced HIV viral loads of participants in a small trial, raising the possibility the medication may one day be added to the portfolio of HIV antiretrovirals. Publishing their findings in Clinical Infectious Diseases, researchers enrolled 18 treatment-naive HIV-positive participants in a double-blind, placebo-controlled crossover trial.

The participants were randomized to two groups. Group A took 12 weeks of twice-daily Valtrex followed by two weeks of no treatment and 12 weeks of placebo. Group B followed the same protocol, but with the treatment portion and the placebo portion switched.

Valtrex reduced viral loads by an average of 42 percent in both groups. The participants’ HIV did not develop resistance to the drug; however, the researchers did not rule out that this could happen if they were treated for longer.

“These findings are very encouraging,” the study’s senior author, Leonid Margolis, PhD, head of the Section on Intercellular Interactions at the National Institutes of Health’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.”

To read the press release, click here.

To read the study abstract, click here.