HIV study: mix of drugs has dramatic effect

Bei Hu

A cure for AIDS might be on the horizon, according to a group of international researchers who found that a combination of anti-HIV drugs can dramaticallly reduce the amount of HIV virus in infected human tissue.
In a study to be published in Friday’s Science Magazine, U.S., Dutch and British investigators, including seven scientists from the University of Minnesota, report a drastic decline in the amount of HIV virus found in the lymph tissue of 10 patients who used a combination of three anti-HIV drugs.
Lymph tissue acts as a reservoir for the virus, the study stated. Earlier research had shown the drugs to have a similar effect on the virus in the bloodstream.
The drugs, which include the protease inhibitor Ritonavir and the reverse transcriptase inhibitors Zidovudine and Lamivudine, worked so well that for one patient who used the combination, the virus was reduced to an undetectable level after 24 weeks of use.
“The study confirms that the drugs can quickly reduce 99.9 percent of all virus in the tissue,” said Stephen Wietgrefe, a scientist with the University’s Department of Microbiology who is involved in the ongoing study.
Last year, scientists found that the drugs, when taken together, can significantly bring down the amount of HIV-virus in the blood. The finding boosted the morale of scientists and infected patients throughout the world.
The latest study marks a major breakthrough in AIDS research because 99 percent of the HIV virus resides in tissue, not the blood.
“What this study shows is just in fact what we had hoped, but nobody knew,” said Winston Cavert, a post-doctoral research associate at the University who was involved in the study.
Cavert said the study raises the hopes of stopping the virus’ attack of the human immune system and possibly restoring the patients’ already impaired immunity.
Planning for the study began in Europe, prior to the drugs’ approval in the United States by the Food and Drug Administration last year.
All of the 10 HIV-infected patients in the study were recruited in Holland. More than half of them had already shown moderate AIDS symptoms by the time they were placed on the medications. Some have stayed on the drugs since early 1996.
An important portion of the research was carried out at the University. Ashley Haase, head of the microbiology department, developed one of the world’s most advanced HIV virus detection techniques that was used in the study. Haase is a senior author of the new report.
Researchers will continue to observe the 10 patients for signs of continued virus suppression. They are also exploring the possibility of restoring destroyed human immune system with the drugs.
Despite the promising results of the latest findings, researchers cautioned that a cure for AIDS remains only a possibility.
Cavert and Wietgrefe said researchers can still find evidence of HIV residue in the tissue of all of the patients.
“When the virus goes to undetectable level, it doesn’t mean it’s gone to zero,” Wietgrefe said. “No one knows whether the virus that is left, if you take away the drugs, will come back and make it as bad as ever.”
It remains a mystery whether the human body can conquer the remaining virus without continued therapy, Wietgrefe said.
Although the medications worked wonders for the 10 patients in the study, Cavert said they have failed in others. The side-effects of the drugs, which include anemia, nausea, gastro-intestinal distress, diarrhea and abnormality in liver functions, put some AIDS patients beyond their protection. The exorbitant therapy, costing $10,000 to $15,000 a year, could be difficult for many to finance.
“Obviously (the cost) is beyond the means of nine-tenths of the world’s population infected with HIV,” Cavert estimated.
Future studies will investigate if the drugs can be replaced with less expensive and less aggressive therapies once the virus levels are remarkably reduced.