Abstract

The level of persistent viremia does not increase after simplification of maintenance antiretroviral therapy to lopinavir/ritonavir alone.

Introduction: Induction-maintenance strategies are being re-evaluated with the goal of simplifying maintenance therapy to a ritonavir-boosted protease inhibitor alone. Persistent, low-level viremia has been detected in most patients on combination therapy despite HIV-1 RNA suppression to <50 copies/ml. Simplification of maintenance therapy could affect the level of persistent viremia. To assess this, we determined HIV-1 RNA levels in longitudinal plasma samples from patients enrolled in the OK Study: a comparison of simplified maintenance therapy with lopinavir/ritonavir (LPV/r) alone vs. continued therapy with 2 NRTI+LPV/r. Of the 42 patients randomized, 4/21 failed therapy in the LPV/r arm vs. 1/21 in the continued therapy arm. The remaining patients were suppressed <50 copies/ml through 48 weeks.

Methods: Plasma samples from each subject at baseline, week-4 and week-8 were tested simultaneously (to eliminate inter-assay variation) using a modified Roche Amplicor HIV-1 RNA assay (v1.5) with a quantification limit of 3.0 copies/ml.

Results: The median level of viremia (copies/ml) between the treatment arms was not significantly different at any time point: Baseline (6.4 vs.4.0), week-4 (3.8 vs. 2.9) and week-8 (3.8 vs. 3.3). In addition, no significant difference was seen in the proportion of patients with undetectable HIV-1 RNA between the treatment arms at any time point. In the LPV/r alone arm, the persistent viremia level between virologic-failures and non-failures was not different at baseline and week-4 but by week-8 there was a trend toward higher level viremia in the failures (p-value=0.087).



Conclusions: The level of persistent viremia in patients suppressed to <50 copies/ml on combination therapy did not change at 4 or 8 weeks after simplification to LPV/r alone, implying that suppression of HIV-1 replication was maintained.