BackgroundFirst results of Trilège demonstrated that the strategy of less intensive antiviral therapy is less effective than continuation of triple-drug therapy.ObjectiveTo compare the final number of failures at month 18 and to study viral dynamics in patients experiencing a virological failure.DesignLongitudinal follow-up from a randomized controlled trial.SettingForty-three AIDS clinical-trial units.PatientsA total of 279 HIV-1 infected adults randomized in Trilège.MeasurementsAnalysis of recurrent values of HIV RNA > 500 copies/ml beyond time to virologic failure.ResultsA total of 83 patients experienced virological failure by month 18; 10 in the zidovudine (ZDV) + lamivudine (3TC) + indinavir (IDV) arm, 46 in the ZDV + 3TC arm, and 27 in the ZDV + IDV arm, confirming previous results. Whatever the treatment ultimately received, 87% of patients had an HIV RNA < 500 copies/ml at month 18 with no statistical difference between randomized arms. Patients experiencing a failure in the triple-drug regimen had a greater tendency to maintain HIV RNA > 500 copies/ml beyond the time of virological failure than patients in both less intensive treatment groups who experienced failure. Lower levels of HIV RNA at failure and reinitiating of either the original triple-drug regimen or a new combination of nucleoside analogue reverse transcriptase inhibitors and protease inhibitors were associated with lower hazard ratios for developing recurrent HIV RNA > 500 copies/ml.ConclusionResults confirmed the failure of a less intensive regimen to maintain patients with a viral suppression (HIV RNA < 500 copies/ml). Although there is a lower incidence of failure in the triple-drug regimen, randomization to a less intensive regimen of ZDV + 3TC or ZDV + IDV was not detrimental, as treatment modification, either to the original triple regimen, or a different regimen was successful.