Predictors of loss of virologic response in subjects who simplified to lopinavir/ritonavir monotherapy from lopinavir/ritonavir plus zidovudine/lamivudine

• Published in: AIDS research and human retroviruses Vol. 25; no. 3; p. 269
• Main Authors: Campo, Rafael E, Da Silva, Barbara A, Cotte, Laurent, Gathe, Joseph C, Gazzard, Brian, Hicks, Charles B, Klein, Cheri E, Chiu, Yi-Lin, King, Martin S, Bernstein, Barry M
• Format: Journal Article
• Language: English
• Published: United States 01.03.2009
• Subjects: Anti-HIV Agents - therapeutic use; Antiretroviral Therapy, Highly Active - methods; CD4 Lymphocyte Count; HIV Infections - drug therapy; HIV Infections - immunology; HIV Infections - virology; HIV-1 - drug effects; Humans; Lamivudine - therapeutic use; Lopinavir; Medication Adherence - statistics & numerical data; Plasma - chemistry; Pyrimidinones - blood; Pyrimidinones - therapeutic use; Ritonavir - therapeutic use; Time Factors; Treatment Outcome; Viral Load; Zidovudine - therapeutic use
• ISSN: 1931-8405
• DOI: 10.1089/aid.2008.0217

Previous studies have demonstrated that lopinavir/ritonavir monotherapy maintained plasma HIV-1 RNA suppression in a large proportion of antiretroviral naive subjects. However, more subjects receiving lopinavir/ritonavir monotherapy experienced confirmed virologic rebound >50 copies/ml compared to a standard three-drug HAART regimen. In this study, we sought to determine the factors associated with maintenance of virologic suppression in subjects receiving lopinavir/ritonavir monotherapy. Antiretroviral-naive HIV-1-infected volunteers were randomized 2:1 to initiate a lopinavir/ritonavir-based combination regimen followed by simplification to lopinavir/ritonavir monotherapy or an efavirenz-based triple combination therapy and followed for 96 weeks. Potential predictors of time to loss of virologic response included baseline demographics, baseline HIV-1 RNA levels, baseline CD4(+) T cell counts, adherence as determined by 4-day subject recall, duration of HIV-1 RNA <50 copies/ml prior to simplification, and lopinavir concentrations. By the Cox proportional hazards model, higher reported adherence levels and higher baseline CD4(+) T cell counts were associated with a greater likelihood of maintaining virologic suppression while receiving lopinavir/ritonavir monotherapy. Lopinavir concentrations, including trough concentrations, were not significantly associated with virologic outcomes. This analysis suggests that adherence and higher baseline CD4(+) T cell counts may help to predict who will sustain virologic suppression with lopinavir/ritonavir monotherapy. The data also suggest that measuring lopinavir concentrations is not useful in predicting virologic response in these patients.