The proportion of participants experiencing virologic failure was analyzed and reported. Virological failure is defined as two consecutive plasma HIV-1 RNA levels of >= 200 copies/mL.

The primary efficacy analysis population included all patients according to their originally assigned Part 1 treatment arm. Virologic failure was assessed only during Part 1 at the assigned dose. Part 2 (rescue arm) does not represent a separate analytical arm for primary endpoint, as entry into Part 2 required prior virologic failure. Therefore, Part 2 patients remain attributed to their original Part 1 arm for the primary efficacy analysis, and Part 2 is not reported as a standalone arm.

Proportion of participants experiencing virologic failure while on PRO 140 monotherapy arm of the study.

Intent toTreat (ITT) population was defined as the set of subjects who were enrolled or randomized and have at least one dose of leronlimab (PRO 140).

The average time to virologic failure after initiating PRO 140 monotherapy was measured in days for confirmed viral load. For the censored subjects (i.e. subjects who did not have an event) the date of event was the time of the last visit date. Virological failure is defined as two consecutive plasma HIV-1 RNA levels of >= 200 copies/mL.

Intent to Treat (ITT) population was defined as the set of subjects who were enrolled or randomized and have at least one dose of leronlimab (PRO 140).

Virologic suppression was defined as plasma HIV-1 RNA levels < 50 copies/mL as quantified by Human Immunodeficiency Virus 1 (HIV-1) Quantitative, RNA (Taqman® Real-Time PCR) assay.

The analysis population includes all subjects who were enrolled or randomized and have at least one dose of PRO 140 and experienced virologic failure. Per protocol participants in Group C arm (700 mg dose) did not receive rescue therapy after virologic failure, therefore, this group/arm was not assessed for viral suppression after virologic failure.

Virologic suppression was defined as plasma HIV-1 RNA levels < 50 copies/mL as quantified by Human Immunodeficiency Virus 1 (HIV-1) Quantitative, RNA (Taqman® Real-Time PCR) assay.

The analysis population includes all subjects who were enrolled or randomized and have at least one dose of PRO 140 and experienced virologic failure. Per protocol participants in Group C arm (700 mg dose) did not receive rescue therapy after virologic failure, therefore, this group/arm was not assessed for viral suppression after virologic failure.

Virologic suppression was defined as plasma HIV-1 RNA levels < 50 copies/mL as quantified by Human Immunodeficiency Virus 1 (HIV-1) Quantitative, RNA (Taqman® Real-Time PCR) assay.

Intent toTreat (ITT) population was defined as the set of subjects who were enrolled or randomized and have at least one dose of leronlimab (PRO 140).

Treatment adherence in the Safety Population for all three treatment groups is provided. Measurement is proportion of subjects that reached treatment week 25 (T25)

Treatment adherence in the Safety Population for all three treatment groups. Safety population is defined as all subjects who received at least one dose of PRO 140.

Total time that participants remain off combination ART regimen will be calculated, defined as the time between start of PRO 140 monotherapy and restart of combination ART Regimen.

The population was defined as the set of subjects who were enrolled or randomized and have at least one dose of leronlimab (PRO 140) and who re-initiated oral combination antiviral therapy.

Mean change in CD4 cell count from baseline to final visit for each participant within the Treatment Phase was calculated and summarized. Visit 48 values were imputed using the last observation carried forward if missing.

The population was defined as the set of subjects who were enrolled or randomized and have at least one dose of leronlimab (PRO 140). Subjects with an undefined change from baseline because of missing data was excluded.

Proportion of participants experiencing emerging resistance exhibited by fold increase (>= 3-fold increase) in maraviroc and PRO 140 FC (IC90 relative to wild-type virus) between baseline and the time of virologic failure, as a measure of post-baseline phenotypic resistance.

The population was defined as the set of subjects who were enrolled or randomized and have at least one dose of leronlimab (PRO 140) and had valid phenotypic assay results for maraviroc/PRO140 at both baseline and virologic failure visit. Subjects with missing or invalid values at either timepoint were excluded.

Central Nervous System (CNS) sub-study Data: mean level of HIV-1 RNA in CSF (cerebrospinal fluid) at T1 (prior to first dose of PRO 140), T4, and VF visits for each treatment group.

The CNS sub-study was analyzed on a small group of selected subjects who were enrolled or randomized and have at least one dose of leronlimab (PRO 140). Subjects with missing or invalid values at either timepoint were excluded. Values below the assay lower limit of detection were imputed as 1 c/mL for calculations.

PRO 140 concentrations were measured in plasma for a subset of participants at T1, T4, and VF timepoints. Participants contributed data only at timepoints where valid measurements were available. Timepoints with missing or invalid data were excluded.

The population was defined as the set of subjects who were enrolled or randomized and have at least one dose of leronlimab (PRO 140). Participants were included in the analysis if they had valid PRO140 concentration data. PRO140 values in plasma below the assay lower limit of detection were imputed as 80 ng/mL for calculations.

PRO 140 concentrations were measured in CSF (cerebrospinal fluid) in a subset of participants at visits T1, T4, and VF.

The population was defined as the set of subjects who were enrolled or randomized and have at least one dose of leronlimab (PRO 140). The CNS sub-study was analyzed on a small group of selected subjects. Only participants with available CSF samples were included in the analysis. Therefore, the number of participants analyzed for this outcome is smaller than the overall number enrolled in the main study. Values below the assay lower limit of detection were imputed as 25 ng/mL for calculations.

Level of HIV-1 RNA in genital secretion at T1 (prior to first dose of PRO 140), T4, and T16 visits.

The GU sub-study was analyzed on a small group of selected subjects. Values below the assay lower limit of detection were imputed as 1 c/mL. Samples that did not have sufficient sample volume for analysis or target was not detected were excluded from the calculations.

Tolerability of repeated subcutaneous administration of PRO 140 as assessed by study participants (using Visual Analogue Scale). Subjects were asked to mark the point that best represents the average pain intensity at the injection site on a horizontal line (100 mm in length) anchored by the following word descriptors at each end, "no pain" on the left side and "pain as bad as it could possibly be" on the right side of the line. The VAS score is determined by measuring in millimeters from the left-hand end of the line to the point that the patient marks. Possible scores range from 0 to 100, with higher scores indicating greater pain.

The Safety population was defined as all subjects who received at least one dose of leronlimab (PRO 140). This population was used for the analysis of safety parameters. Timepoints with no available data were excluded from the analysis.

Adverse Events (AEs) are presented based on severity, per Investigator discretion. Severity grades were based on the Division of Aids (DAIDS) grading guidelines. For safety analyses, Grade 3 and 4 AEs were summarized separately for treatment periods corresponding to Part 1 and Part 2 due to differences in dosing and treatment exposure. Participants who entered Part 2 (rescue treatment) received an increased dose of leronlimab and therefore constitute a distinct safety population. For this reason, AEs occurring during Part 2 are represented separately from Part 1, although Part 2 does not represent a separate study arm for efficacy analyses and participants remain attributed to their original Part 1 treatment arm in the overall study design.

The Safety population was defined as all subjects who received at least one dose of leronlimab (PRO 140). This population was used for the analysis of safety parameters. For safety analyses, Grade 3 and 4 AEs were summarized by treatment periods (Part 1 and 2) according to treatment received. Participants who entered Part 2 are included in both their original Part 1 and Part 2 safety populations. Therefore, the total across safety groups exceeds the number of unique participants enrolled.

Serious adverse events (SAEs) that occurred during the study include all adverse events that occurred from when the subject signed the informed consent form. For safety analyses, SAEs were summarized separately for treatment periods corresponding to Part 1 and Part 2 due to differences in dosing and treatment exposure. Participants who entered Part 2 (rescue treatment) received an increased dose of leronlimab and therefore constitute a distinct safety population. For this reason, SAEs occurring during Part 2 are represented separately from Part 1, although Part 2 does not represent a separate study arm for efficacy analyses and participants remain attributed to their original Part 1 treatment arm in the overall study design.

The Safety population was defined as all subjects who received at least one dose of leronlimab (PRO 140). This population was used for the analysis of safety parameters. For safety analyses, SAEs were summarized by treatment periods (Part 1 and 2) according to treatment received. Participants who entered Part 2 (rescue treatment) are included in both their original Part 1 and Part 2 safety populations. Therefore, the total across safety groups exceeds the number of unique participants enrolled.