Intermittent Antiretroviral Drug Therapy May Boost Immune Control of HIV
Regular "bursts" of intermittent antiretroviral drugs may effectively "teach" the immune system to fight HIV on its own, according to a new study published in the recent issue of Science, the Scripps Howard News/Newark Star-Ledger reports. In the study, researchers tested three groups of rhesus monkeys infected with SIV, the monkey strain of HIV. Following the initial phase of infection, when the immune system temporarily blocks the virus, researchers initiated continuous drug therapy to the monkeys of the first group, but switched drug administration to "three weeks on and three weeks off" for a second group. A third group received no treatment. After 21 weeks, drug therapy was halted, and both groups of treated monkeys showed successful viral control, with low levels of the virus in their blood and similar levels of immune cells. Soon after, however, the virus "rebounded quickly" in monkeys who had received continuous treatment, with their immune levels falling as low as those in the monkeys who had never been treated. Immune response in monkeys that had received intermittent treatment remained high, with "virtually undetectable" viral levels. Study author Dr. Franco Lori of the Research Institute for Genetic and Human Therapy cautioned that the results were "preliminary." He said, "More research is necessary to learn how these findings could work in a clinical setting." However, he noted that in addition to administering fewer drugs, "it seems that we can stimulate the immune system to better control the virus, which is a completely different way of looking at treatment." Daily cocktails of drugs have been a "revolution in treating the virus over a long period of time," but they do not "eliminate HIV from the body." Further, the daily regimen of drugs is costly, must be closely monitored, and causes "unpleasant" side effects for many patients. Although there have been "isolated" cases of patients, such as the "Berlin patient," who remained healthy after interrupting therapy several times, HIV typically "resumes its attack" on the immune system weeks or mere days after therapy cessation. Lori said, "In the past, we've taken a few humans and followed them to see what happens, but we couldn't define the exact role of treatment interruptions before this. This is the first randomized, controlled study showing the differences between interrupted and continued therapy" (Bowman, Scripps Howard News/Newark Star-Ledger, 11/24).This is part of the KHN Morning Briefing, a summary of health policy coverage from major news organizations. Sign up for an email subscription.