Suboptimal Suppression with Maraviroc plus a Boosted Protease Inhibitor?
Until larger studies are done, such regimens are probably best avoided.
A nucleoside reverse transcriptase inhibitor (NRTI) backbone remains standard in combination antiretroviral therapy, but there is ongoing interest in developing NRTI-sparing regimens to avoid the drugs' short- and long-term toxicities.
In a recent multinational, open-label, manufacturer-sponsored trial, 121 treatment-naive HIV-infected individuals with confirmed CCR5-tropic virus were randomized to receive ritonavir-boosted atazanavir in combination with either tenofovir/FTC or maraviroc at the unusually low dose of 150 mg once daily.
At week 48, rates of virologic suppression (HIV RNA <50 copies/mL) were 75% in the maraviroc group and 84% in the tenofovir/FTC group. The median change from baseline in CD4-cell count was similar between groups (+173 and +187, respectively). Almost all patients in both arms reported treatment-related adverse effects — most commonly jaundice, diarrhea, or nausea. Grade 3 or 4 adverse effects were more common in the maraviroc group (48% vs. 30%); the two patients who had treatment-limiting adverse effects were both in that group. Pharmacokinetic analyses demonstrated adequate plasma concentrations of maraviroc with the dose used.
Comment: This trial was not powered to detect meaningful differences in treatment outcome, and the authors characterize it as a proof-of-concept study to show that an NRTI-sparing maraviroc/boosted–protease inhibitor (PI) regimen results in virologic suppression in the majority of patients.
However, readers should note that longer follow-up of the same patients, presented at the recent 2012 International AIDS conference, undercuts these results somewhat: At week 96, the maraviroc group continued to lag behind the tenofovir/FTC group in complete virologic suppression (68% vs. 82%); low-level virologic breakthroughs were also more frequent in the maraviroc group (JW AIDS Clin Care Aug 20 2012). Thus, pending a suitably powered study, clinicians should probably avoid the maraviroc/boosted PI options unless there is really no better alternative.
Published in Journal Watch HIV/AIDS Clinical Care February 4, 2013
Mills A et al. Maraviroc once-daily nucleoside analog-sparing regimen in treatment-naive patients: Randomized, open-label pilot study. J Acquir Immune Defic Syndr 2013 Feb 1; 62:164.
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