Interrupting HIV treatment may have its benefits

Patients who take closely monitored breaks from HIV treatment might suffer fewer side effects without an increased chance of developing resistance to the drugs, researchers report. Highly Active Anti-Retroviral Therapy (HAART) is the most effective HIV treatment, but it must be taken for life and can have serious side effects, including liver damage.

The findings may mean that some patients could take less of these drugs, reducing the costs of the highly expensive treatment.”The results provide reassurance about the one risk that was feared-development of resistance and loss of efficacy of treatment,” says Bernard Hirschel at the Geneva University Hospital in Switzerland, who led the research. The trial involved 430 people with HIV, 146 of whom received continuous HAART drug treatment. The remaining 284 patients received these drugs only when the level of their CD4 immune cells fell below 350 cells per microlitre of blood-HIV attacks and destroys the CD4 immune cells, so they are measured as a marker of disease progression. Hirschel explains that a healthy person typically has a CD4 cell count above 500 cells per mircolitre of blood and that HIV patients are said to have developed AIDS when their CD4 counts drop below 200 cells per microlitre. The group taking the intermittent treatment received about half the amount of drugs as the patients in the continuous-treatment group. Setting thresholdsBoth groups fared similarly over their two-year study period, Hirschel and colleagues say. Contrary to the findings of similar large studies, however, no significant difference was seen between the groups in terms of the development of “resistance mutations” in the virus. Although, of the 10 patients who showed signs of such resistance, seven were in the group that received interrupted treatment.The success of the interrupted therapy may be due to do with the unique design of the study: Patients had to have higher levels of protective immune cells still circulating in their blood before stopping treatment compared to other similar trials. Setting this threshold higher may have somehow reduced the risk of these dangerous mutations, the researchers suggest.Those receiving interrupted therapy had fewer serious side effects. For example, only 16% suffered diarrhoea compared to 23% of those on continuous treatment. Patients on the interrupted course also reported fewer neurological complications. Hirschel says that while interrupted therapy may not suit all HIV patients, “there are those who have a lot of side effects, and such people can take comfort in the findings”. Not at homeHowever, at the end of the trial the CD4 counts of the patients on continuous treatment was significantly higher than those on interrupting therapy-96% had CD4 counts above 350 cells per microlitre, compared to just 61% of those on interrupted treatment. However, while participants on interrupted treatment had a higher risk of low CD4 counts, they did not have a greater risk of serious infection than their counterparts in the study.People with HIV should not stop taking their medication until further studies clarify the associated risks, cautions Eric Daar, head of the HIV medicine division at the Harbor-UCLA Medical Centre in Torrance, California, US. Daar stresses that Hirschel’s group closely tailored the interruptions of therapy based on detailed monitoring of patients’ immune systems. Trying this method at home, he says, could be deadly.HIV is an incurable disease that can lead to AIDS. Antiretroviral therapies work by reducing the viral load to a manageable level.(Source: The Lancet: Geneva University Hospital in Switzerland: August 2006).