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Evaluation and Management of Virologic FailureQuestion 10/10

A 71-year-old man with chronic HIV and a CD4 count of 136 cells/mm3 returns to clinic for follow-up on a salvage antiretroviral regimen of darunavir-cobicistat, maraviroc, fostemsavir, and tenofovir alafenamide-emtricitabine. He has intermittently encountered problems with adherence. An HIV RNA level obtained on the day of the visit shows a value of 1,860 copies/mL and HIV genotypic resistance testing is ordered.

Which one of the following is TRUE about maraviroc resistance?

If the HIV tropism assay fails to detect subpopulations of HIV that can utilize the CXCR4 receptor (X4-tropic, dual-tropic, mixed-tropic), these strains will increasingly become the dominant strain under the selective pressure of the CCR5 antagonist maraviroc.
Figure 1. Outgrowth of Pre-existing Non-R5-Tropic HIV with Selective Maraviroc Pressure.
If the HIV tropism assay fails to detect subpopulations of HIV that can utilize the CXCR4 receptor (X4-tropic, dual-tropic, mixed-tropic), these strains will increasingly become the dominant strain under the selective pressure of the CCR5 antagonist maraviroc.
Illustration: David H. Spach, MD
HIV can circumvent maraviroc blockage by mutations in the HIV gp120 region that allow for gp120 to bind to the host CCR5 receptor, even in the presence of bound maraviroc. The mutations usually occur in the V3 loop of HIV gp120.
Figure 2. Maraviroc Resistance with Alterations in HIV gp120.
HIV can circumvent maraviroc blockage by mutations in the HIV gp120 region that allow for gp120 to bind to the host CCR5 receptor, even in the presence of bound maraviroc. The mutations usually occur in the V3 loop of HIV gp120.
Illustration: David H. Spach, MD
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Question Last Updated
January 28th, 2025

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