A regimen of either efavirenz or lopinavir-ritonavir plus two nucleoside reverse-transcriptase inhibitors (NRTIs) is recommended for HIV-1 patients starting initial therapy; however, it is not known which of these two regimens has greater efficacy. The alternative regimen of lopinavir-ritonavir plus efavirenz could prevent toxic effects associated with NRTIs, the study authors noted.
An open-label study was conducted to compare the three regimens for initial therapy: efavirenz plus two NRTIs (efavirenz group), lopinavir-ritonavir plus two NRTIs (lopinavir-ritonavir group), and lopinavir-ritonavir plus efavirenz (NRTI-sparing group). Seven hundred fifty-seven patients with a median CD4 count of 191 cells per cubic millimeter and a median HIV-1 RNA level of 4.8 log10 copies per milliliter were randomly assigned to the three groups.
During follow-up of a median 112 weeks, the time to virologic failure was longer in the efavirenz group than in the lopinavir-ritonavir group (P=0.006) though it was not significantly different in the NRTI-sparing group than either of the two groups. At week 96, the proportion of patients with fewer than 50 copies of plasma HIV-1 RNA per milliliter was 89 percent in the efavirenz group, 77 percent in the lopinavir-ritonavir group and 83 percent in the NRTI-sparing group (P=0.003 for the comparison between the efavirenz group and the lopinavir-ritonavir group). There was no significant difference in the time to discontinuation due to toxic effects between the groups. At virologic failure, the NRTI-sparing group recorded more antiretroviral resistance mutations than did the other two groups.
"Virologic failure was less likely in the efavirenz group than in the lopinavir-ritonavir group," the authors concluded. "The virologic efficacy of the NRTI-sparing regimen was similar to that of the efavirenz group but was more likely to be associated with drug resistance."
05/15/08
UNITED STATES: Class-Sparing Regimens for Initial Treatment of HIV-1 Infection
Source: New England Journal of Medicine Vol. 358; No. 20: P. 2095-2106 (05.15.08):: Sharon A. Riddler, MD, MPH; Richard Haubrich, MD; A. Gregory DiRienzo, PhD; Lynne Peeples, MS; William G. Powderly, MD; Karin L. Klingman, MD; Kevin W. Garren, PhD; Tania George, PharmD; James F. Rooney, MD; Barbara Brizz, MHSEd, BSN; Umesh G. Lalloo, MD; Robert L. Murphy, MD; Susan Swindells, MB, BS; Diane Havlir, MD; John W. Mellors, MD; the AIDS Clinical Trials Study Group Study A5142 Team; Courtesy of the CDC National Center for HIV, STD, and TB Prevention