
Maraviroc is the first CCR5 antagonist approved for the treatment of HIV-1 infection. The use of maraviroc is associated with significant decreases in HIV viral load and increases in CD4 counts in antiretroviral treatment-experienced patients with CCR5-tropic virus when used as an add-on to optimized antiretroviral treatment. In clinical trials, patients with dual- or mixed-tropic virus (which can infect cells using CXCR4 and/or CCR5 receptors) who were treated with maraviroc demonstrated no difference in HIV viral load compared with patients who received placebo. A recent study compared maraviroc plus lamivudine/zidovudine with efavirenz plus lamivudine/zidovudine; maraviroc did not demonstrate noninferiority when undetectable virus was defined as <50 copies/mL; however, maraviroc did meet noninferiority criteria when undetectable virus was defined as <400 copies/mL. Maraviroc is not recommended for patients with CXCR4-tropic, dual-tropic, or mixed-tropic virus; for antiretroviral-naive patients; or for..