[Lopinavir/ritonavir in new initial antiretroviral treatment strategies]

According to evidence from randomized controlled trials and epidemiological data, the antiretroviral treatment (ART) of choice has consisted of the combination of 2 nucleoside analog reverse-transcriptase inhibitors (NRTI) plus 1 non-nucleoside analog reverse-transcriptase inhibitor (NNRTI) or a protease inhibitor (PI) for more than 17 years. There are several unresolved issues, notably the toxocity associated with NRTI, especially thymidine analogs, and the possibility of cross resistance, which may affect subsequent treatment. The development of new antiretroviral drugs with simpler dosing regimens and lower toxicity has led to evaluation of innovative strategies such as dual therapy for initial ART in treatment-naive, with the aim of preventing long-term toxicity and increasing treatment adherence. Despite encouraging results, some combinations have proven unsatisfactory. The strategies with favorable results to date consist of twice-daily lopinavir/ritonavir (LPV/r)-based regimens, those in the PROGRESS (LPV/r + raltegravir) and GARDEL (LPV/r + lamivudine) trials, and the combination of darunavir and raltegravir (NEAT 001 trial), although the latter observed a higher tendency (statistically nonsignificant) to virological failure in the dual combination arm. These trials were based on the use of NRTI-sparing regimens consisting of 2-3 fully- active agents for highly-active ART in treatment-naïve HIV-positive patients. Recent studies provide evidence supporting the use of NRTI-sparing regimens in HIV-infected patients with failure to an initial NNRTI-based ART regimen. The present review will discuss only LPV/r-based innovative strategies in initial ART regimens.