July 10, 2001 -- There is good news for children and adults taking AIDS drug combinations: The treatments may keep working much longer than once thought.
When taken religiously, these so-called drug cocktails can keep HIV in check. They do this so well that even very sensitive tests can't find virus in the blood. It's still there, though -- and what patients fear the most is the day it once again rears its ugly head.
Current guidelines say that when the virus becomes detectable again in the blood, it means the drugs holding it in check are about to fail. The resurgence is thought to happen as the virus changes its structure to the point that that the anti-HIV drugs no longer work, a phenomenon called drug resistance. But studies in the July 11 issue of the Journal of the American Medical Association indicate that an occasional "blip" of detectable virus doesn't necessarily mean drug-resistant HIV has arrived.
"Therapy is effective in some individuals in preventing the development of drug resistance," Deborah Persaud, MD, tells WebMD. "The clear message is that it is possible to suppress virus replication ... for prolonged periods."
Persaud, assistant professor of pediatrics at Johns Hopkins University School of Medicine in Baltimore, led a team that discovered a way to evaluate for drug-resistance mutations. They found that even after four years of treatment, the virus developed no new drug-resistance mutations.
Some of the patients in the study had previously taken a lot of anti-HIV drugs, and their virus was resistant to some of them. But when the virus could be controlled by a new set of drugs, even these patients developed no new resistant virus.
A second study by Diane V. Havlir, MD, and co-workers at the University of California, San Diego, looked at 254 patients enrolled in a study of an anti-HIV combination therapy of Crixivan (indinavir ), Retrovir (AZT), and Epivir (lamivudine). They found that patients who had occasional blips of detectable HIV were no more likely to suffer a breakout of drug-resistant HIV than patients whose HIV remained undetectable.
The researchers suggest current HIV treatment guidelines may have to be changed, as they may cause doctors and patients to give up too soon on a treatment that still works.
An editorial by leading AIDS researcher Steven G. Deeks, MD, of the University of California, San Francisco, warns that the new findings apply only to patients whose anti-HIV drug combinations include a type of drug called a protease inhibitor. People on other HIV drug regimens might not experience the same phenomenon -- and will need to be evaluated in further studies.
Deeks also notes that nobody yet knows where the suddenly detectable virus comes from. It might be from the so-called "latent reservoir" of AIDS virus -- hidden pockets of virus in the body that elude anti-HIV drugs -- or perhaps from a small amount of virus that persists in the blood despite effective therapy.
"If these blips simply reflect release of virus from reservoirs then it would be unlikely that [the HIV therapies stop working]," Deeks tells WebMD.
"On the other hand, if blips reflect active replication, then [drug] resistance might occur," he adds. "But [one of these studies] ? suggests that such resistance-related mutations do not emerge rapidly."
The dark side of the new findings is that even with anti-HIV treatment, the virus keeps on keeping on. This underscores the importance of taking anti-HIV drugs as directed -- every single day.