• Proportion of patients with plasma viral load below 50 copies/mL . [ Time Frame: after 48 weeks of follow-up ] [ Designated as safety issue: No ]
  

• Time to the appearance of viral load >50 copies/mL in both branches (two consecutive determinations with 4-week separation between both). [ Time Frame: During the 48 weeks of follow-up. ] [ Designated as safety issue: No ]
  
• Evolution of the CD4 lymphocyte count at 48 weeks. [ Time Frame: during 48 weeks of follow-up ] [ Designated as safety issue: No ]
  
• Pattern of mutations associated with resistance in patients presenting virological failure. [ Time Frame: When there is a virological failure ] [ Designated as safety issue: No ]
  
• Incidence of adverse clinical effects and laboratory alterations, giving rise or not to the withdrawal of the investigational treatment. [ Time Frame: during the 48 weeks of follow-up ] [ Designated as safety issue: Yes ]
  
• Incidence of AIDS-defining events (CDC C events, 1993). [ Time Frame: during the 48 weeks of follow-up ] [ Designated as safety issue: Yes ]
  
• Mortality by any cause. [ Time Frame: during the 48 weeks of follow-up ] [ Designated as safety issue: Yes ]
  

RTNI (reverse transcriptase nucleoside inhibitors) are a regular part of most antiretroviral combinations. The presence of a smaller or greater degree of cross resistance among all RTNI is increasingly better described and acknowledged, whereby the number of salvage regimens that may be built following the appearance of this resistance to these drugs is by no means unlimited.

This proactive treatment change in patients on RTNI-based regimens while the viral load is still suppressed would avoid the selective replication period under antiviral pressure following the failure of the regimen in which resistance-associated mutations accumulate. This therapeutic approach has demonstrated its effectiveness in clinical practice, albeit not in this scenario.

If we wait until the viral load is detectable there is sufficient evidence that resistance to RTNI will appear and that this resistance will compromise future salvage options.

To intensify with this proactive approach these combinations based on N/NNRTI (nucleotide analog), the NNRTI are an optimal alternative.There is vast experience with NVP in simplification/maintenance trials. In direct comparative simplification studies in patients with virological response, the response rates with NVP or EFV have shown no differences. With a relative risk (RR) of virological failure of 0.54 with regard to the continuation of PI (protease inhibitors), NVP is one of the best simplification treatment options in HIV-1-infected patients.