Common herpes drug lowers HIV levels in patients
The findings of researchers from Case Western Reserve University and the Civic Association for Health and Education in Lima, Peru, have been published online in the journal Clinical Infectious Diseases.
Some forms of HIV-1, the most prevalent strain of the HIV virus in the world, have become resistant to existing medications. Then, the discovery reverses earlier thinking that the oral drug valacyclovir was effective in reducing a patient's HIV viral load only if he also had herpes simplex 2, or genital herpes.
People with herpes are at greater risk for contracting HIV when they have a recurrence of genital herpes lesions. Valacyclovir, which has relatively minor side effects, is one of the antiviral drugs used to treat those outbreaks.
Scientists previously thought that valacyclovir helped reduce HIV levels and worked by decreasing the immune activation caused by HSV-2. With fewer immune cells to attack, the theory went, HIV could not spread as widely.
But Leonid Margolis of the National Institutes of Health believed another explanation might exist. After conducting laboratory studies with acyclovir, an earlier sibling drug of valacyclovir, Margolis saw that the medication clearly blocked HIV reproduction, even in the absence of the herpes virus.
The work of Margolis, head of the NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development, paved the way for CWRU and Peru researchers to embark on their study.
Based on what the researchers saw in the lab, they were pretty hopeful that they would see the same thing happen in humans, said Dr. Benigno Rodriguez, associate professor of medicine and infectious diseases at CWRU School of Medicine and one of the senior authors of the study. "But it wasn't by any means a foregone conclusion," he said.
Beginning in June 2009, researchers began looking for HIV patients at University Hospitals Case Medical Center and in Peru to enroll in the clinical trial. Only HIV patients who were not yet taking antiretroviral medication, because their immune systems were still relatively intact, were eligible.
Because the majority of HIV patients take antiretroviral medication, recruitment proved to be a challenge, and took nearly three years.
In the end, six of the 18 patients enrolled in the study were in Cleveland, with the remaining 12 in Peru. All but one of the patients is male.
A CD4 count is the number of a type of cell found in the blood. The higher the count, the more effective a patient's immune system is in fighting infections.
The study design called for half the patients to take valacyclovir twice daily for 12 weeks, while the other half took a placebo for the same period of time. After a two-week break from taking any medications, the two groups switched. The study ended in July 2012.
When study participants took valacyclovir, their HIV viral loads went down. When they were given the placebo, their HIV viral loads went up. ■