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

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.

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.

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

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.

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 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.

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 (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.

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

Maintenance of CD4+ count defined as having greater than or equal to 200 cells/mm^3 at Baseline 2 (BL2) and greater than or equal to 200 cells/mm^3 at Week 48.

Improvement of CD4+ count defined as having from 100 to less than 200 CD4+ cells/mm^3 at Baseline 2 (BL2) and greater than or equal to 200 cells/mm^3 at Week 48.

A serious AE (SAE) is an event which: results in death, is life-threatening, disabling or incapacitating; is a congenital anomaly in the offspring of a patient who received study drug; requires or prolongs inpatient hospitalization; jeopardizes the patient or require medical or surgical intervention to prevent one of the outcomes above; any Grade 4 laboratory value considered by the investigator clinically significant or that requires an action; any injection site reaction that meets SAE criteria above. Non-serious AEs reported include pneumonia and non-serious AEs that led to discontinuation.