Human immunodeficiency virus-1 sequence changes and drug resistance mutation among virologic failures of lopinavir/ritonavir monotherapy: AIDS clinical trials group protocol A5230

Abstract

Background. The mechanism of virologic failure (VF) of lopinavir/ritonavir (LPV/r) monotherapy is not well understood. We assessed sequence changes in human immunodeficiency virus-1 reverse-transcriptase (RT) and protease (PR) regions. Methods. Human immunodeficiency virus-1 pol sequences from 34 participants who failed second-line LPV/r monotherapy were obtained at study entry (SE) and VF. Sequence changes were evaluated using phylogenetic analysis and hamming distance. Results. Human immunodeficiency virus-1 sequence change was higher over drug resistance mutation (DRM) sites (median genetic distance, 2.2%; Q1 to Q3, 2.1%-2.5%) from SE to VF compared with non-DRM sites (median genetic distance, 1.3%; Q1 to Q3, 1.0%-1.4%; P