A Study to Evaluate the Safety and Efficacy of Adding Enfuvirtide to Oral Highly Active Antiretroviral Therapy (HAART) in Human Immunodeficiency Virus (HIV) Patients With Prior Treatment Experience

To assess the efficacy of enfuvirtide (Fuzeon) added to HAART compared to treatment with HAART alone in achieving and maintaining viral load suppression.

This study consisted of two phases. In the Induction phase patients were randomized at Baseline 1 (BL1) in a 1:2 ratio to receive: * I1: HAART or * I2: Enfuvirtide (90 mg twice a day) + HAART. Participants who achieved viral suppression \< 50 copies/mL by week 24, confirmed by week 28 or earlier, qualified to enter the Maintenance Phase which started at Baseline 2 (BL2), four weeks after confirmation of response. The Maintenance Phase consisted of three treatment groups: * M1: HAART continued (patients from I1) Patients on ENF+HAART (I2) were re-randomized (at a 1:1 ratio) at BL2 to: * M2: Enfuvirtide stopped and HAART continued * M3: Enfuvirtide + HAART continued. The duration of the Maintenance Phase was from BL2 up to 48 weeks after BL1. BL2 could start at the earliest at Week 12 and at the latest Week 32.