If subjects were receiving RCV (Racivir®), to continue in the open-label treatment period, the amount of virus in the blood must drop by at least 2/3 during the first 14 days of the blinded treatment period. For example, if subjects enter the study with 10,000 copies of the HIV virus per milliliter (ml) of blood, then to continue in the open-label period, the virus level must drop to 3,162 copies or less, per ml of blood. Open-label means that participating subjects and the study doctor or study staff will know what treatment subjects were receiving.