Inclusion Criteria:

A subject will be eligible for inclusion in this study only if all of the following criteria apply:

• Male or female between 18 and 65 years of age inclusive, at the time of signing the informed consent.
• A female subject is eligible to participate if she is of non-childbearing potential, defined as:
• Pre-menopausal females with a documented bilateral oophorectomy, tubal ligation or hysterectomy; or
• Postmenopausal defined as 12 months of spontaneous amenorrhea. A follicle stimulating hormone level will be performed to confirm post-menopausal status. For this study, FSH levels > 40 MlU/ml and estradiol < 40 pg/ml (<140 pmol/L) is confirmatory.
• Male subjects must agree to use one of the contraception methods listed in Section 8.1. This criterion must be followed from the time of the first dose of study medication until 14 days after the last dose of study medication.
• CD4+ cell count greater than or equal to 200 cells/mm3 and plasma HIV-1 RNA greater than or equal to 5000 copies/mL at Screening.
• No current antiretroviral therapy and have not received any in the 12 weeks prior to first dose.
• For subjects who have received antiretroviral treatment in the past, adequate treatment options to construct HAART therapy with at least 3 active antiretrovirals for Optimized Therapy, as selected by the Investigator.
• Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the consent form.

Exclusion Criteria

A subject will not be eligible for inclusion in this study if any of the following criteria apply:

• A positive screening Hepatitis B surface antigen; positive screening hepatitis C virus (HCV) antibody and detectable HCV ribonucleic acid (RNA) on subsequent testing. If the hepatitis C antibody is positive but the HCV RNA is undetectable, the subject may be included in the study.
• AST and ALT > 3ULN at Screening. A single repeat is allowed for eligibility determination.
• Inadequate renal function at Screening, defined as either a serum creatinine >1.5 mg/dL or a calculated creatinine clearance (CrCl) ≤ 50 mL/min. A single repeat serum creatinine is allowed to determine eligibility.
• Any acute laboratory abnormality at screening which, in the opinion of the investigator, should preclude the subject's participation in the study of an investigational compound. Any grade 4 laboratory abnormality at screening, with the exception of CPK, will exclude a subject from study participation unless the investigator can provide a compelling explanation for the laboratory result(s) and has the assent of the sponsor. A single repeat is allowed for eligibility determination.
• A positive drug screen at screening and baseline. A minimum list of drugs that will be screened for include amphetamines, barbiturates, cocaine or PCP.
• History of regular alcohol consumption, defined as an average weekly intake of >14 drinks for males or >7 drinks for females, within 6 months of Screening.

Note: One drink is equivalent to 12 g of alcohol: 12 ounces (360 ml) of beer, 5 ounces (150 ml) of wine or 1.5 ounces (45 ml) of 80 proof distilled spirits.

• Any condition (including alcohol or drug abuse) which, in the opinion of the investigator, could interfere with the subject's ability to comply with the dosing schedule and protocol evaluations or which might compromise the safety of the subject.
• Prior treatment with an integrase inhibitor (greater than or equal to 1 dose).
• Treatment with radiation therapy or cytotoxic chemotherapeutic agents within 30 days of study drug administration or anticipated need for such treatment within the study.
• Treatment with immunomodulating agents (such as systemic corticosteroids, interleukins, interferons) or any agent with known anti-HIV activity (such as hydroxyurea or foscarnet) within 30 days of study drug administration.
• Treatment with any vaccine within 30 days prior to receiving study medication.
• An active Center for Disease Control and Prevention (CDC) Category C disease, except cutaneous Kaposi's sarcoma not requiring systemic therapy during the trial.
• Pregnant females as determined by positive serum or urine hCG test at screening or prior to dosing.
• Lactating females.
• Use of multivitamins or antacids within 24 hours prior to the first dose of investigational product.
• History of sensitivity to any of the study medications, or components thereof or a history of drug or other allergy that, in the opinion of the investigator or GSK Medical Monitor, contraindicates their participation. In addition, if heparin is used during PK sampling, subjects with a history of sensitivity to heparin or heparin-induced thrombocytopenia should not be enrolled.

Note: Study medications refer to GSK1265744 or placebo.

• The subject has participated in a clinical trial and has received an investigational product within the following time period prior to the first dosing day in the current study: 30 days, 5 half-lives or twice the duration of the biological effect of the investigational product (whichever is longer).
• Where participation in the study would result in donation of blood or blood products in excess of 500 mL within a 56 day period.
• History of clinically relevant pancreatitis or hepatitis within the previous 6 months.
• Subjects with a pre-existing condition interfering with normal gastrointestinal anatomy or motility, hepatic and/or renal function, that could interfere with the absorption, metabolism, and/or excretion of the study drugs.
• Exclusion Criteria for Screening ECG (A single repeat is allowed for eligibility determination):

Exclusion Criteria for Screening ECG:

Males Females Heart rate <45 and >100 bpm <50 and >100 bpm QRS duration >120 msec >120 msec QTc interval (Bazett) > 450 msec > 450 msec Non-sustained (≥ 3 consecutive beats) or sustained ventricular tachycardia. Sinus Pauses >3 seconds. 2nd degree (Type II) or higher AV block. Evidence of previous myocardial infarction (pathologic Q waves, S-T segment changes (except early repolarization)).