April 1 (HealthDay News) -- An investigational drug might help people with HIV who don't respond to standard anti-retroviral therapy, a new study suggests.

Currently, the "gold standard" treatment for HIV is known as HAART, for highly active anti-retroviral therapy, which consists of a number of drugs that reduce viral load by stopping the virus from replicating. If it works well, HAART can increase recipients' life expectancy, but it's not effective in about 10 percent of people who take it, partly because some develop resistance to the drugs.

In the study, researchers tested the effectiveness of a molecule called D-1mT and anti-retroviral therapy (ART) in macaque monkeys with simian immunodeficiency virus (SIV), which is similar to HIV in humans. After six days of treatment, only three of the macaques had detectable SIV levels, and after 13 days, only very low SIV levels could be found in two of the macaques.

When the researchers gave D-1mT to eight macaques that were not treated with ART, there was no change in the levels of virus in the blood after 13 days of treatment.

"Our early findings suggest that D-1mT could be used alongside anti-retroviral therapy to stop the virus from replicating," Dr. Adriano Boasso, from Imperial College London, said in a news release from the college.

"The disease can only progress if the virus is replicating, so if we can slow replication down, we can reduce the impact of the disease on the patient's life," Boasso said. "We still need to figure out how D-1mT is working, then we can think about developing this as a potential treatment for HIV."

The study is in the April 1 issue of the Journal of Immunology.

SOURCE: Imperial College London, news release, March 31, 2009