Predictors of sustained response to therapy resumption after treatment interruption in HIV-infected patients failing antiretroviral therapy

In order to evaluate whether a sustained virologic response to therapy resumption after treatment interruption can be achieved in the setting of virologic failure, we reviewed retrospectively the data relating to 56 human immunodeficiency virus (HIV)-infected subjects selected from 3,145 patient charts. At the time of treatment interruption (study entry), the median (interquartile range) CD4+ counts and HIV-RNA levels were respectively 247 (127-502) x 10(6) cells/L and 4.24 (3.68-5.02) log(10) copies/ml, and the patients had been exposed to eight (5-9) antiretroviral drugs. After treatment interruption, the patients received at least three drugs depending on their treatment history. Forty-eight weeks after the resumption of therapy, 19 of the 56 patients (34%) had HIV-RNA levels of <400 copies/ml and, in comparison with study entry, the difference in the median increase in CD4+ counts between the virologic responders and non-responders (83 vs. 8.5 x 10(6) cells/L) was statistically significant (P = 0.02). Multivariate analysis showed that higher peak HIV-RNA levels before treatment interruption were independently predictive of virologic failure, whereas a longer treatment interruption period independently correlated with a virologic response. Four patients with CD4+ counts of <200 x 10(6) cells/L at study entry developed HIV-related clinical events. A sustained virologic response to therapy resumption after treatment interruption can be achieved in the setting of virologic failure. An evaluation of clinical history may help to identify the patients who are more likely to respond. (C) 2004 Wiley-Liss, Inc.