702 patients in whom previous antiretroviral
treatment had failed, with a plasma viral load higher
than 1000 copies per mL and any CD4 cell count,
were enrolled. All individuals received an investigatorselected
background regimen containing a fully active
ritonavir-boosted protease inhibitor and a second
drug. Many study participants had documented
baseline resistance mutations to one or more classes of
antiretroviral drugs. None had been previously exposed
to elvitegravir or raltegravir.