Genebat M, Ruiz-Mateos E, León JA et al. J Antimicrob Chemother 2009;64:845–9.
The results of this study showed high correlation between virological responses among HIV-infected subjects receiving 8 days of functional monotherapy with maraviroc and the results of the Enhanced Sensitivity Trofile® (Monogram BioSciences, San Francisco, CA, USA) assay for HIV tropism.
The use of maraviroc (MVC) is indicated for patients with CCR5-using (R5) viruses only; as a result, a tropism test is required prior to initiation of therapy. A number of limitations exist with regards to use of these assays; these include high cost, unavailability, delayed time for test results, and “non-reportable” results in a limited of patients. The current authors investigated the correlation between the virological response to short-term MVC therapy and the results of a tropism assay as a possible clinical approach to assessing HIV tropism. Thirty-four viremic patients were enrolled (19 were on a structured treatment interruption and 15 were viremic while receiving highly active antiretroviral therapy) and received 8 days of MVC 300 mg twice daily. Six additional subjects were enrolled as controls and received no MVC treatment. Patients’ viral load measurements were evaluated on days 0, 2, 5, and 8, with a positive result being defined as a reduction of ≥1 log10 HIV RNA copies/mL or an undetectable viral load (<40 copies/mL) on day 8 after MVC initiation. The Enhanced Sensitivity Trofile® (Monogram Biosciences, San Francisco, CA, USA) assay was employed, with all samples for assay being obtained within 12 weeks of MVC dosing.