Class-Sparing Regimens for Initial Treatment of HIV-1 Infection

Several regimens are used as initial antiretroviral therapy for HIV-1 infection, but few direct comparisons are available. In this randomized, open-label study, efavirenz plus two nucleoside reverse-transcriptase inhibitors (NRTIs), lopinavir–ritonavir plus two NRTIs, and lopinavir–ritonavir plus efavirenz were compared. Initial therapy with efavirenz plus two NRTIs was associated with less virologic failure than was lopinavir–ritonavir plus two NRTIs. The NRTI-sparing regimen of lopinavir–ritonavir plus efavirenz had virologic efficacy similar to that of efavirenz plus two NRTIs but was more likely to select for drug resistance. Initial therapy with efavirenz plus two NRTIs was associated with less virologic failure than was lopinavir–ritonavir plus two NRTIs. The NRTI-sparing regimen of lopinavir–ritonavir plus efavirenz had virologic efficacy similar to that of efavirenz plus two NRTIs but was more likely to select for drug resistance. Current practice guidelines recommend the use of efavirenz or ritonavir-boosted protease inhibitor regimens containing two nucleoside reverse-transcriptase inhibitors (NRTIs) for initial therapy of human immunodeficiency virus type 1 (HIV-1) infection. 1 , 2 These recommendations are derived from expert opinion and the results of clinical trials, but to our knowledge well-powered, head-to-head comparisons of these regimens have not been performed. 3 – 5 Although NRTIs are included in all recommended antiretroviral regimens, toxic effects, especially lipoatrophy associated with the thymidine analogues, 6 , 7 has raised interest in regimens that do not contain NRTIs. Pilot studies of NRTI-sparing regimens have shown good virologic efficacy, but adequately . . .