Chuck Bednar for redOrbit.com – @BednarChuck
A drug originally developed to fight the virus that causes genital herpes could also be effective in treating HIV in some patients, the US National Institutes of Heath (NIH) revealed on Friday.
In a study of 18 patients, researchers from the NIH along with colleagues from Case Western Reserve University in Cleveland, Emory University in Atlanta and Lima, Peru found that the pill valacyclovir appeared to reduce the HIV levels of patients who do not have genital herpes.
GlaxoSmithKline is really excited about this story
Dr. Leonid Margolis, the head of the section on intercellular interactions at the NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and lead author of a study published in the journal Clinical Infectious Diseases, called the findings “very encouraging” and said that he and his colleagues hope to confirm them in a larger study.
[STORY: HIV vaccines increase infections rates in primates]
“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,” Dr. Margolis added. The research team’s project was funded through the agency’s Bench to Bedside Program.
According to NBC News, valacyclovir (sold under the brand name Valtrex) is prescribed to people with genital herpes, and less frequently to people with cold sores caused by another strain of the herpes virus. Experts knew that treating herpes in HIV patients appeared to control both of the viruses, but now they demonstrate that it can effectively treat HIV in those without herpes.
Attaching phosphates does the trick
The results follow a 2008 study by the same group of researchers that showed that acyclovir can suppress HIV in laboratory cultures of human tissues infected with various strains of the herpes virus. Valacyclovir is a prodrug for acyclovir because it’s structurally similar to acyclovir, and is converted to acyclovir in the body, the researchers explained. Valacyclovir was used in the study because it remains in the blood longer than acyclovir and can be taken less frequently.
[STORY: Protein inactivates virtually all strains of HIV]
Previous studies demonstrated that acyclovir reduces HIV levels in patients coinfected with HIV and HSV-2, the virus that causes genital herpes. That effect had been attributed to the anti-HSV-2 activity of the drug, but the new research indicates that valacyclovir directly interferes with the reproductive processes of the HIV virus and did not require the presence of HSV-2.
“HSV-2 chemically alters acyclovir, by attaching chemical groups known as phosphates to it. It is this altered form of the drug that suppresses HSV-2,” the NIH explained. Dr. Margolis and his colleagues “believe this form also interferes with HIV’s ability to reproduce,” and he said that he “wanted to find out” if this mechanism “could operate in the cells of patients with HIV.”
They recruited 18 HIV-infected patients, none of whom had HSV-2, and treated them with valacyclovir. Half of the patients were given the anti-herpes drug twice a day for 12 weeks, while the others received a placebo. After two weeks, the placebo group received valacyclovir while the group originally treated with the drug switched to the placebo.
“The researchers found that when the patients took valacyclovir, their blood HIV levels declined significantly,” the NIH said. “Typically, HIV patients take a cocktail of several anti-HIV drugs because a single drug is not enough to suppress the virus. Multiple HIV medications also hinder the virus’ ability to develop resistance to the drugs.”
[STORY: Llama antibodies capable of neutralizing HIV]
They also conducted a genetic analysis and found that the HIV in the study participants did not become resistant to valacyclovir. However, since the virus does have a long history of becoming resistant to the medications used to treat it, Dr. Margolis and his associated are not ruling out the possibility that it will eventually become resistant to the treatment method.
Even so, due to the drug’s potential in lowering HIV levels, they believe that valacyclovir could eventually be added to the cocktail of drugs given to those infected with the virus. Before that can happen, however, they advise that large-scale randomized trials and cost-effective analyses could be warranted to further explore the potential of the drug in treating HIV infection.
—–
Follow redOrbit on Twitter, Facebook, Google+, Instagram and Pinterest.
Comments