Factors associated with virological failure in HIV-1-infected patients receiving darunavir/ ritonavir monotherapy

Abstract

Background. Our objective was to determine virological and clinical characteristics associated with virological failure in human immunodeficiency virus (HIV)-infected patients switching to darunavir/ritonavir (DRV/r) monotherapy. Methods. The main outcome was virologic rebound, defined as 2 consecutive measurements of HIV-1 plasma RNA viral load (VL) >50 copies/mL. A logistic model was used to investigate which variables were predictive of a virologic rebound at weeks 48 (W48) and 96 (W96). Results. Receiving DRV/r monotherapy was associated with virologic rebound at W48 (P = .016) and W96 (P = .002), comparable to triple therapy. In the DRV/r monotherapy group, at W48, having a VL >50 copies/mL at day 0 and even a baseline ultrasensitive VL >1 copy/mL were predictive factors to virologic rebound (P = .042 and P = .025, respectively). At W96, shorter time of prior antiretrovial therapy (ART) exposure (odds ratio [OR] = 2.93 per 5 years decrease; P=.006), higher HIV-1 DNA at day 0 (OR=2.66 per 1 log 10 copies/10 6 cells increase; P=.04) and adherence <100% (OR = 3.84 vs 100%; P = .02) were associated with an increased risk of rebound. Conclusions. Factors associated with virological failure in patients receiving DRV/r monotherapy were having an initial blip, shorter time of antiretroviral treatment before monotherapy, and an adherence <100% during monotherapy. The importance of prior duration exposure to ART was in agreement with the impact of HIV-1 blood reservoir and VL level at baseline. © The Author 2011. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved.