Researchers Compare Different Antiretroviral Combination Therapies’ Ability To Suppress Viral Loads in Patients on Initial Treatment of HIV-1 Infection
A triple-combination therapy that includes the antiretroviral drug efavirenz is the most effective among two other widely used antiretroviral regimens at suppressing HIV viral loads for initial treatment of HIV-1 infection, according to a study published in the May 15 issue of the New England Journal of Medicine, the Pittsburgh Tribune-Review reports.
For the study, Sharon Riddler, associate professor of medicine at the University of Pittsburgh School of Medicine, and colleagues compared the efficacy of three antiretroviral drug combinations among 753 people enrolled in NIH's AIDS Clinical Trials Group at 55 centers (Heinrichs, Pittsburgh Tribune-Review, 5/15).
Researchers found that at week 96 of the study, 89% of the participants taking the combination of efavirenz and two nucleoside reverse transcriptase inhibitors had less than 50 copies of HIV per milliliter of blood; 77% of those taking the combination lopinavir/ritonavir and two NRTIs had less than 50 copies; and 83% taking a combination of efavirenz and lopinavir/ritonavir without NRTIs -- called NRTI-sparing therapy -- had less than 50 copies. They also found that at a median follow-up of 112 weeks, the time to virologic failure was longer for those in the efavirenz group than for those in the lopinavir/ritonavir group. However, the time to virologic failure was not significantly different in the NRTI-sparing group compared with the other two groups. In addition, the researchers noted that the NRTI-sparing therapy was nearly as effective as the efavirenz treatment but "was more likely to be associated with drug resistance" (Riddler et al., NEJM, 5/15).
"What we found is that one regimen performs the best, but all of them work pretty well," Riddler said. She added that because people have different reactions to the drugs and because pregnant women should not take efavirenz, doctors need a variety of alternatives. Drug side effects can include cardiovascular disease, fatigue, and kidney and liver problems, the Tribune-Review reports. Riddler added that it is important for people to take the drugs consistently to prevent resistance.
John Mellors, director of the HIV/AIDS program at UP's Medical Center and senior co-author of the study, said that the findings offer researchers who are working to develop more effective antiretrovirals a drug regimen to compare with other treatments.
"This is a critically important study," Joel Gallant -- a professor at the Johns Hopkins University School of Medicine, who did not participate in the study -- said. The research "really compares what have been considered the gold standards" of treatment, he added (Pittsburgh Tribune-Review, 5/15).
The study abstract is available online.