A Phase IIIb Study of the Safety, Efficacy, and Tolerability of Switching to a Fixed-dose Combination of Abacavir/Dolutegravir/ Lamivudine From Current Antiretroviral Regimen

Inclusion Criteria:

• Be able to understand and comply with protocol requirements, instructions, andrestrictions;

• Be likely to complete the study as planned;

• Be considered appropriate candidates for participation in an investigative clinicaltrial with oral medication (e.g., no active substance abuse, acute major organdisease, or planned long-term work assignments out of the country, etc.).

• Signed and dated written informed consent is obtained from the subject or thesubject's legal representative prior to screening

• HIV-1 infected men or women >=18 years of age;

• A female may be eligible to enter and participate in the study if she: a. Is ofnon-childbearing potential either defined as post-menopausal (12 months of spontaneousamenorrhea and >=45 years of age) or physically incapable of becoming pregnant withdocumented tubal ligation, hysterectomy, or bilateral oophorectomy or,

• A female may be eligible to enter and participate in the study if she: b. Is ofchildbearing potential with a negative pregnancy test at both Screening and Day 1 andagrees to use one of the following methods of contraception to avoid pregnancy:Complete abstinence from intercourse from 2 weeks prior to administration of studydrug, throughout the study, and for at least 2 weeks after discontinuation of allstudy drugs; Double barrier method (e.g., male condom/spermicide, malecondom/diaphragm, diaphragm/spermicide); Any intrauterine device (IUD) with publisheddata showing that the expected failure rate is <1% per year ; Male partnersterilization prior to the female subject's entry into the study and this male is thesole partner for that subject; Approved hormonal contraception for subjects randomlyassigned to the ABC/DTG/3TC arm or approved hormonal contraception plus a barriermethod for subjects assigned to continued antiretroviral therapy arm; Any other methodwith published data showing that the expected failure rate is <1% per year.

• Any contraception method must be used consistently, in accordance with the approvedproduct label and for at least 2 weeks after discontinuation of study drug. Achildbearing potential female subject who starts the study using complete abstinenceas her contraceptive method and decides to become sexually active must use the doublebarrier method either as a bridge to an approved hormonal contraception (if possible)or as a method of choice to be maintained from that moment onwards.

• All subjects participating in the study should be counselled on safer sexual practicesincluding the use of effective barrier methods (e.g., male condom/spermicide).

• Within the last year, 2 consecutive plasma HIV-1 Ribonucleic acid (RNA) measurements <50 copies/millilitres (c/mL) and plasma HIV-1 RNA<50 c/mL at Screening (<75 bDeoxyribonucleic acid [bDNA] is considered equal to <50 c/mL); Subjects who present atinitial screening with a viral load between 50 to 200 c/mL can be retested once withinthe screening period.

• Must be on current regimen (whether first or second line Combination antiretroviraltherapy [cART]) for at least 6 months prior to Screening;

• Acceptable stable cART regimens prior to Screening include: • Boosted PI (orAtazanavir [ATV]) unboosted) + 2 NRTIs, NNRTI + 2 NRTIs, • INI + 2 NRTIs. For subjectson an INI, their INI at Screening must be RAL or Elvitegravir (EVG)

• Any switch to a second line regimen, defined as change of a single drug or multipledrugs simultaneously, must have occurred due to tolerability and/or safety concerns.

• Subject must have achieved plasma HIV-1 RNA level <50 c/mL within 6 months of start ofinitial cART regimen with no plasma HIV-1 RNA level >200 c/mL following initialsuppression;

• Documentation that the subject is negative for the human leukocyte antigen (HLA)B*5701 allele;

Exclusion Criteria: Exclusionary Medical Conditions

• Women who are breastfeeding;

• Any evidence of an active (Centers for Disease Control and Prevention [CDC] CategoryC) disease. Exceptions include cutaneous Kaposi's sarcoma not requiring systemictherapy and historic CD4+ cell counts of <200 cells/cubic millimeter (mm).

• Subjects with any degree of hepatic impairment;

• Subjects positive for hepatitis B virus surface antigen (+HBsAg) at Screening or withan anticipated need for hepatitis C virus (HCV) therapy during the study;

• History or presence of allergy to the study drugs or their components or drugs oftheir class;

• Ongoing malignancy other than cutaneous Kaposi's sarcoma, basal cell carcinoma, orresected, non-invasive cutaneous squamous cell carcinoma, or cervical intraepithelialneoplasia; other localized malignancies require agreement between the investigator andthe study medical monitor for inclusion of the subject;

• Subjects who, in the investigator's judgment, pose a significant suicidality risk.Recent history of suicidal behavior and/or suicidal ideation may be considered asevidence of serious suicide risk; Exclusionary Treatments Prior to Screening or Day 1

• Treatment with an HIV-1 immunotherapeutic vaccine within 90 days of Screening;

• Treatment with any of the following agents within 28 days of Screening: radiationtherapy, cytotoxic chemotherapeutic agents, any immunomodulators that alter immuneresponses;

• Exposure to an experimental drug or experimental vaccine within either 28 days, 5half-lives of the test agent, or twice the duration of the biological effect of thetest agent, whichever is longer, prior to the first dose of study drug;

• A history of use of only mono or dual NRTI therapy prior to starting cART;

• Use of etravirine at time of switch;

• Use of DTG at time of switch;

• Subjects receiving any prohibited medication listed in the protocol and who areunwilling or unable to switch to an alternate medication Exclusionary Laboratory Values or Clinical Assessments at Screening

• Evidence of primary viral resistance based on the presence of anyresistance-associated major PI or any NRTI, NNRTI, or INI mutation in any priorresistance genotype assay result;

• Any verified Grade 4 laboratory abnormality, with the exception of Grade 4triglyceride abnormalities. A single repeat test is allowed during the screeningperiod to verify a result;

• Any acute laboratory abnormality at Screening, which, in the opinion of theinvestigator, would preclude the subject's participation in the study of aninvestigational compound;

• Alanine aminotransferase (ALT) >=5 times the upper limit of normal (ULN), or ALT >=3 ×ULN and bilirubin >=1.5 × ULN (with >35% direct bilirubin);

• Subject has CrCl of <50 mL/min using Modification of Diet in Renal Disease (MDRD);

• QTc (Bazett) >=450 msec or QTc (Bazett) >=480 msec for subjects with bundle branchblock. The QTc is the QT interval corrected for heart rate according to Bazett'sformula (QTcB). The QTc should be based on a single QTc value electrocardiogram (ECG)obtained.

• Eligibility of subjects for study participation will be decided by the investigatorsafter taking into consideration various country specific guidelines, andnotwithstanding the above mentioned minimum inclusion and exclusion criteria.