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

Number of Participants With Viral Suppression: HIV-1 RNA < 50 Copies/mL During the Induction Phase

Time frame · From Baseline 1 to Week 28

Participants whose viral load achieved suppression (HIV-1 RNA \< 50 copies/mL) at Week 24 at the latest, confirmed at Week 28 (2 consecutive assessments ≥ 28 days apart) were defined as responders. Patients who discontinued the study or did not respond to assigned treatment by week 28 were considered as non-responders.

Time to Achieving HIV-1 RNA < 50 Copies/mL During the Induction Phase

Time frame · Baseline 1 until Week 28.

The time to achieving HIV-1 RNA \<50 copies/mL was counted from Baseline 1 until the first of the two consecutive \<50 copies/mL measurements. Patients who discontinued from the study or patients who did not have confirmed virological response by week 28 were classed as non-responders and censored at Week 24.

Number of Participants With Viral Suppression HIV-1 RNA < 400 Copies/mL During the Induction Phase

Time frame · From Baseline 1 to Week 28

Participants whose viral load achieved suppression (HIV-1 RNA \< 400 copies/mL) by Week 24 at the latest, confirmed at Week 28 (2 consecutive assessments ≥ 28 days apart) were defined as responders. Patients who discontinued the study or did not respond to assigned treatment by Week 28 were considered as non-responders.

Change From Baseline to Week 24 in Viral Load

Time frame · Baseline and Week 24

Change from Baseline in log10 HIV-1 RNA at Week 24. Least squares means were calculated from an analysis of covariance (ANCOVA) model with treatment, a flag variable "removed ENF at re-randomization" and Baseline viral load as independent variables.

Change From Baseline to Week 24 in Cluster Differentiation Antigen Four Positive (CD4+) Cell Counts

Time frame · Baseline and Week 24

Change from Baseline in CD4+ Cell Counts at Week 24. Least squares means were calculated from an ANCOVA model with treatment as an independent variable.

Percentage of Induction Phase Participants With Viral Load < 50 Copies/mL at 48 Weeks

Time frame · Week 48

The percentage of participants from the Induction Phase who maintained HIV-1 RNA \< 50 Copies/mL at Week 48. Patients who discontinued from the study, rebounded to ≥ 50 copies/mL (i.e., had two consecutive readings ≥ 50 copies/mL), had missing data or had virological failure by Week 48 were classed as non-responders.

Percentage of Maintenance Phase Participants With Viral Load < 50 Copies/mL at 48 Weeks

Time frame · Week 48

The percentage of participants from the Maintenance Phase who maintained HIV-1 RNA \< 50 copies/mL at Week 48. Patients who discontinued from the study, rebounded to ≥ 50 copies/mL (i.e., had two consecutive readings ≥ 50 copies/mL), had missing data or had virological failure by Week 48 were classed as non-responders.

Change From Baseline to Week 48 in Cluster Differentiation Antigen Four Positive (CD4) Cell Counts

Time frame · Baseline 1 and Week 48

Change from Baseline in CD4 Cell Counts at Week 48. Least squares means were calculated from an ANCOVA model with treatment and baseline CD4 count as independent variables.

Time to Loss of Viral Response During the Maintenance Phase

Time frame · From Baseline 2 to Week 48.

The time to loss of viral response (defined as HIV-1 RNA \<50 copies/mL) was counted from Baseline 2 until the first of two consecutive ≥50 copies/mL measurements. Only patients who were qualified for entering the Maintenance Phase were included in the analysis.

Time to Virological Failure During the Maintenance Phase

Time frame · From Baseline 2 to Week 48.

Time to virological failure (defined as HIV-1 RNA ≥ 400 copies/mL) was counted from Baseline 2 until the first of the two consecutive ≥400 copies/mL measurements. Only patients who were qualified for entering the Maintenance Phase were included in the analyses.

Number of Participants With Virological Failure During the Maintenance Phase

Time frame · From Baseline 2 to Week 48.

Virological failure was defined by 2 consecutive HIV-1 RNA values ≥ 400 copies/mL during the Maintenance Phase.