Antiretroviral naive adults with HIV-@ RNA @ copies per milliliter and a CD@ count @ cells per microliter were randomized @:@ to receive an STR of elvitegravir/cobicistat/emtricitabine / tenofovir alafenamide ( E/C/F / TAF ) or elvitegravir/cobicistat/emtricitabine / tenofovir disoproxil fumarate ( E/C/F / TDF ) , plus placebo for @ weeks .