The percentage of participants with Plasma Human Immunodeficiency Virus-1 (HIV-1) Ribonucleic Acid (RNA) \<50 c/mL at Week 48 was assessed using the Missing, Switch or Discontinuation = Failure (MSDF), as codified by the Food and Drug Administration (FDA) "snapshot" algorithm. This algorithm treated all participants without HIV-1 RNA at Week 48 as nonresponders, as well as participants who switched their concomitant ART prior to Week 48 as follows: background ART substitutions non-permitted per protocol (one background ART substitution was permitted for safety or tolerability); background ART substitutions permitted per protocol unless the decision to switch was documented as being before or at the first on-treatment visit where HIV-1 RNA was assessed. Otherwise, virologic success or failure was determined by the last available HIV-1 RNA assessment while the participant was on-treatment in the randomized phase of the study.

Plasma samples were collected for quantitative HIV-1 RNA analysis at Week 16. The analysis was performed using the time to loss of virological response (TLOVR) dataset. In the TLOVR dataset, participant responses at a specified threshold of HIV-1 RNA (\<50 copies/mL) are determined by using the Food and Drug Administration's TLOVR algorithm. Using the TLOVR algorithm, participants are considered to have failed on therapy if they never achieved confirmed RNA levels below the threshold, if they had confirmed rebound of RNA above the threshold, if they made a non-permitted change in background regimen, or if they permanently discontinued investigational product for any reason. Data are reported per the Week 16 report. In later cuts of the data, the Week 16 values may have changed (because of the nature of the TLOVR algorithm).ITT-E Population included all randomized participants who received at least one dose of study medication

Change from Baseline in Plasma Human Immunodeficiency Virus-1 (HIV-1) Ribonucleic Acid (RNA) was calculated as the Day 11 value minus the Baseline value. Blood samples for the measurement of HIV-1 RNA levels were obtained throughout the treatment period (Day 1 to Day 11).

AUC is defined as the area under the GSK1349572 concentration-time curve as a measure of drug exposure. AUC(0-inf) is defined as the area under the concentration-time curve from time zero (pre-dose) extrapolated to infinite time. AUC(0-24) is defined as the area under the concentration-time curve from time zero (pre-dose) to24 hours. Blood samples for pharmacokinetic (PK) analysis of GSK1349572 were obtained on Day 1at pre-dose (within 15 minutes prior to dose) and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours post GSK1349572 dose administration.

Cmax is defined as the maximum observed plasma concentration, and C24 is defined as the concentration at 24 hours post dose. Blood samples for PK analysis of GSK1349572 were obtained on Day 1at pre-dose (within 15 minutes prior to dose) and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours post GSK1349572 dose administration. From the plasma concentration-time curve, Cmax was determined by standard non-compartmental analysis using WinNonlin Pro 4.1 or higher.

tmax is defined as the time to the maximum obsevered plasma concentration. Absorption lag time is defined as the time taken for a drug to appear in the systemic circulation following administration. tlag was estimated based on PK sampling times of 0 (pre-dose), 0.5, 1, 1.5, 2 3, 4, 6, 8, 12, and 24 hours post-dose. Blood samples for PK analysis of GSK1349572 were obtained on Day 1at pre-dose (within 15 minutes prior to dose) and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours post GSK1349572 dose administration. From the plasma concentration-time curve, tmax was determined by standard non-compartmental analysis using WinNonlin Pro 4.1 or higher.

The terminal half-life (t1/2) of GSK1349572 is defined as the time required for the plasma concentration of GSK1349572 to reach half of its original concentration. Blood samples for PK analysis of GSK1349572 were obtained on Day 1at pre-dose (within 15 minutes prior to dose) and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours post GSK1349572 dose administration.

The CL/F is defined as the apparent total clearance of the drug from plasma after oral administration. Blood samples for PK analysis of GSK1349572 were obtained on Day 1at pre-dose (within 15 minutes prior to dose) and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours post GSK1349572 dose administration.

AUC is defined as the area under the GSK1349572 concentration-time curve as a measure of drug exposure. AUC(0-tau) is defined as the area under the concentration-time curve over the dosing interval. Blood samples for PK analysis of GSK1349572 were obtained on Day 10at pre-dose (within 15 minutes prior to dose) and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours post GSK1349572 dose administration.

C0 is defined as the pre-dose concentration. Ctau is defined as the concentration at the end of the dosing interval. Cmin is defined as the minimum observed concentration during one dosing interval. Cmax is defined as the maximum obsevered plasma concentration. Blood samples for PK analysis of GSK1349572 were obtained on Day 10 at pre-dose (within 15 minutes prior to dose) and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours post GSK1349572 dose administration.

tmax is defined as the time to the maximum obsevered plasma concentration. Blood samples for PK analysis of GSK1349572 were obtained on Day 10 at pre-dose (within 15 minutes prior to dose) and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours post GSK1349572 dose administration. From the plasma concentration-time curve, tmax was determined by standard non-compartmental analysis using WinNonlin Pro 4.1 or higher.

The terminal half-life (t1/2) of GSK1349572 is defined as the time required for the plasma concentration of GSK1349572 to reach half of its original concentration. Blood samples for PK analysis of GSK1349572 were obtained on Day 10 at pre-dose (within 15 minutes prior to dose) and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours post GSK1349572 dose administration.

The CL/F is defined as the apparent total clearance of the drug from plasma after oral administration. Blood samples for PK analysis of GSK1349572 were obtained on Day 10 at pre-dose (within 15 minutes prior to dose) and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours post GSK1349572 dose administration.

An AE is defined as any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a medicinal product. An SAE is defined as any untoward medical occurrence that, at any dose, results in death, is life threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, is a congenital anomaly/birth defect, or is an event of possible drug-induced liver injury. Refer to the general Adverse AE/SAE module for a complete list of AEs and SAEs.

Concomitant medications received during the study period are presented by generic term. Only those concomitant medications that were received by at least two participants are presented. "Multiple ingredient" is the term used in the statistical package for items that contain more than one active ingredient.

Blood pressure measurement included systolic blood pressure (SBP) and diastolic BP (DBP). Change in the mean blood pressure from Baseline was calculated as the post-Baseline value minus the Baseline value. Data are presented for change from Baseline at Day 1 (2 hours post dose \[hrs\]), Day 4 (1 hr pre-dose), Day 7 (1 hr pre-dose), and Day 10 (1 hr pre-dose and 2 hrs post dose).

Heart rate is the measure of heart beats per minute (bpm). Change in the mean heart rate from Baseline was calculated as the post-Baseline value minus the Baseline value. Data are presented for change from Baseline at Day 1 (2 hours post dose \[hrs\]), Day 4 (1 hr pre-dose), Day 7 (1 hr pre-dose), and Day 10 (1 hr pre-dose and 2 hrs post dose).

A 12-lead electrocardiogram (ECG) was performed by qualified personnel at the site after the participant had rested for at least 5 minutes in a semi-recumbent or supine position. If a QTc measurement of \>=500 milliseconds (msec) was noted on a scheduled or unscheduled ECG, two additional ECGs were to be obtained within 5 minutes to confirm the abnormality. The number of participants with abnormal clinically significant (CS) and not clinically significant (NCS) ECG findings are presented here. The site determined if an ECG finding is significant or not. ECGs were obtained at Screening, Day 1 (pre-dose \[twice\] and then 1.0, 1.5, and 2.0 hours \[hrs\] post dose), Day 4 (pre-dose), Day 7 (pre-dose), Day 10 (pre-dose and then 1.0, 1.5, and 2.0 hrs post dose), Day 11 (prior to the 24 hr PK sample \[pre lab\]), and Follow-up.

Clinical laboratory toxicities were graded according to the National Institutes of Allergy and Infectious Diseases (NIAID), Division of Acquired Immunodeficiency Syndrome (DAIDS). Grade 1, Mild; Grade 2, Moderate; Grade 3 (G3), Severe; Grade 4 (G4), Life-threatening or disabling; Grade 5, Death. Data are presented only for Grade 3 and Grade 4 laboratory abnormalities. Clinical laboratory abnormalities included: increased glucose, lipase, decreased platelets, and triglycerides.