At week @ , proportions with HIV-@ RNA < @ copies/mL were @ % ( @ of @ subjects with baseline HIV-@ RNA > @ c/mL initially randomized to TDF ) , @ % ( @ of @ subjects with HIV-@ RNA < @ c/mL who switched PBO to TDF ) and @ % ( @ of @ subjects failed randomized PBO plus OBR with HIV-@ RNA > @ c/mL and switched PBO to TDF ) .