Boston, Massachusetts (PressExposure) January 13, 2010 -- The initial treatment for patients with the human immunodeficiency virus (HIV) consists of the use of fixed-dose combination nucleoside reverse-transcriptase inhibitors (NRTIs) with a nonnucleoside reverse-transcriptase inhibitor or a ritonavir-boosted protease inhibitor. Researchers at Brigham and Women's Hospital (BWH), working within the NIH-funded AIDS Clinical Trials Group (ACTG), found that the NRTI combination tenofovir-emtricitabine (Truvada, Gilead Sciences) was more safe and effective than abacavir-lamivudine (Epzicom, GlaxoSmithKline). This research is published online and in the December 2 issue of the New England Journal of Medicine.
It was unknown which of these two available NRTI combinations used to treat HIV has greater efficacy and safety. The researchers compared four once-daily antiretroviral regimens as initial therapy for HIV infection; they found a significant difference in virologic efficacy, according to the NRTI combination, in patients with high amounts of HIV RNA in their blood. "For those patients treated with abacavir-lamivudine, the amount of time before virologic failure and the first adverse event occurred were both significantly shorter than in those assigned to tenofovir DF-emtricitabine," said Paul Sax, MD, clinical director for the Division of Infectious Diseases at BWH.
The researchers assigned participants beginning treatment for HIV to one of the four treatment groups which included: abacavir-lamivudine or tenofovir disoproxil fumarate (DF)-emtricitabine in combination with efavirenz or ritonavir-boosted atazanavir. At a median follow-up of 60 weeks, among the 797 patients with HIV-1 RNA levels of 100,000 copies per milliliter or more, the time to virologic failure was significantly shorter in the abacavir-lamivudine group than in the tenofovir DF-emtricitabine group, with 57 virologic failures in the abacavir-lamivudine group versus 26 in the tenofovir DF-emtricitabine group. The time to the first adverse event was also shorter in the abacavir-lamivudine group. These findings led an independent Data and Safety Monitoring Board to recommend stopping the comparison between NRTIs among those with HIV RNA levels > 100,000 copies.
"These findings have important implications for clinical practice, especially for patients who are beginning HIV therapy with high viral loads," said Dr. Sax. "While both treatment strategies were highly effective, the results clearly showed that tenofovir DF-emtricitabine was both more effective and better tolerated."
This research was funded by grants from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, with additional support from the General Clinical Research Center units, funded by the National Center for Research Resources.