Pharmacokinetics of lopinavir determined with an ELISA test in youths with perinatally acquired HIV

Objective: To investigate the plasma levels of lopinavir by enzyme-linked immunosorbent assay (ELISA) in a cohort of patients who were vertically infected with human immunodeficiency virus 1 (HIV). Methods: Plasma levels of lopinavir (Cmin) were determined by ELISA test in patients treated with lopinavir/ritonavir-based combined antiretroviral therapy who had achieved virological response after 4 wk of therapy. Reference lopinavir concentrations were Cmin 1-8 μg/mL. Correlation between lopinavir plasma concentration and continuous variables was evaluated by mean of Pearson correlation coefficient. Differences in lopinavir (LPV) concentration for binary categorical variables were assessed by Mann-Whitney test, while for variables with more than two categories Kruskal-Wallis test was used. Results: Thirty-four patients were enroled; median age was 133 mo (15-265). The median lopinavir dose tested was 383.5 mg/kg (IQR: 266.6-400 mg/kg), with a median plasma concentration of 8.8 μg/mL (IQR: 5-14 μg/mL). Lopinavir Cmin was <1 μg/mL in only one sample (2.9 %), while 14 samples had C min between 1 and 8 μg/mL (41.2 %) and 19 (55.9 %)>8 μg/mL. No significant correlations were found between plasma concentrations of lopinavir and the continuous variables considered in the study. A negative but, not completely significant, correlation was found between plasma drug concentration and body mass index (r=-0.29; p=0.09). Conclusions: The use of a simple and relatively cost-effective methodology might render therapeutic drug monitoring (TDM) appeal in the daily clinical practice.