Predictive value of HIV-1 replication capacity and phenotypic susceptibility scores in antiretroviral treatment-experienced patients

Objectives The aim of the study was to determine the prognostic value of HIV replication capacity (RC) for subsequent antiretroviral (ARV) treatment response in ARV-experienced patients. Methods RC and phenotypic resistance testing were performed at baseline and week 12 on plasma samples from patients randomized to undergo a 12-week ARV drug-free period (ARDFP) or initiate immediate salvage therapy (no-ARDFP group) in the Options in Management with Antiretrovirals (OPTIMA) trial. Dichotomous and incremental phenotypic susceptibility scores (dPSSs and iPSSs, respectively) were calculated. The predictive value of RC and PSS for ARV therapy response and/or ARDFP was evaluated using multivariate regression analysis and Pearson correlations. Results In 146 no-ARDFP subjects, baseline RC (50.8%) did not change at week 12 and was not correlated with CD4 cell count or viral load changes at week 12 (P = 0.33 and P = 0.79, respectively) or at week 24 (P = 0.96 and P = 0.14, respectively). dPSS predicted virological but not CD4 cell count response to ARV therapy at weeks 12, 24 and 48 (P = 0.002, P