Investigators at each centre randomly assigned patients ( 1:1 ; block size of four ; stratified by time to suppression [ < 1 year or > 1 year ] and nadir CD4 cell count [ < 100 cells per L or > 100 cells per L ] ; computer-generated random sequence ) to continue triple treatment or switch to dual treatment ( oral lopinavir 400 mg and oral ritonavir 100 mg twice daily plus oral lamivudine 300 mg once daily ) .