At week 144 , proportions with HIV-1 RNA < 50 copies/mL were 30.4 % ( 7 of 23 subjects with baseline HIV-1 RNA > 1000 c/mL initially randomized to TDF ) , 41.7 % ( 5 of 12 subjects with HIV-1 RNA < 1000 c/mL who switched PBO to TDF ) and 0 % ( 0 of 2 subjects failed randomized PBO plus OBR with HIV-1 RNA > 1000 c/mL and switched PBO to TDF ) .