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

Rafael E. Campo, Barbara A. Da Silva, Laurent Cotte, Joseph C. Gathe, Brian Gazzard, Charles B. Hicks, Cheri E. Klein, Yi Lin Chiu, Martin S. King, Barry M. Bernstein

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


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 virologie 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 virologie 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 virologie 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.

Original languageEnglish (US)
Pages (from-to)269-275
Number of pages7
JournalAIDS research and human retroviruses
Issue number3
StatePublished - Mar 1 2009

ASJC Scopus subject areas

  • Immunology
  • Virology
  • Infectious Diseases


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