Correlation between the Trofile® test and virological response to a short-term maraviroc exposure in HIV-infected patients

Abstract

Objectives: The current validated assay to determine tropism of HIV variants is Trofile®, which has some limitations. The aim of this work was to correlate the virological response to a short-term maraviroc exposure with Trofile®. Methods: From 1 July 2008 to 1 March 2009, 34 consecutive HIV-infected patients with detectable viral load during the last 6 months began an 8 day exposure to maraviroc (MCT group); six HIV-infected patients without antiretroviral therapy received no treatment (control group). Plasma viral load was evaluated on days 0, 2, 5 and 8. Baseline Trofile® was performed in MCT group patients. The maraviroc clinical test (MCT) was considered positive if viral load was undetectable (<40 HIV-RNA copies/mL) or a reduction ≥1 log10 HIV-RNA copies/mL was achieved after 8 days of maraviroc exposure. Results: Global concordance between MCT and Trofile® was 93.5%. In patients with R5 virus according to Trofile®, MCT was positive in 19/20 (concordance 95%); in patients with dual/mixed virus, MCT was negative in 10/11 (concordance 90.9%). An additional phenotypic tropism assay was performed in patients with discordance between MCT and Trofile®, being concordant with MCT in both cases. Three patients showed a non-reportable Trofile® result, and all of them achieved undetectability after MCT. Conclusions: A clinical approach like short-term maraviroc exposure could be an additional resource to genetic and phenotypic HIV tropism assays. This clinical approach shows high concordance with Trofile®, and could allow patients with non-reportable results by Trofile® to benefit from maraviroc therapy. © The Author 2009. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.