• Percentage of Participants With Plasma HIV-1 RNA <50 c/mL Using Food and Drug Administration (FDA) Snapshot Algorithm [ Time Frame: At Week 24 ]
  Percentage of participants with HIV-1 RNA<50 c/mL was obtained using FDA Snapshot algorithm. The Snapshot algorithm treated all participants without HIV-1 RNA data at the visit of interest (either due to missing plasma HIV-1 RNA assessment but on study, or due to permanent discontinuation of study treatment prior to visit window) as virologic non-success, as well as participants who switched from first line regimen of DTG + 3TC FDC for any reason prior to the visit of interest. Confidence intervals were calculated based on the Exact Clopper-Pearson method. Percentage of participants with plasma HIV-1 RNA <50 c/mL obtained using FDA Snapshot algorithm are presented.
• Time to Viral Suppression (HIV-1 RNA<50 c/mL) for Participants Who Had HIV-1 RNA >= 50 c/mL at Baseline [ Time Frame: Up to Week 24 ]
  Time of viral suppression for participants who had HIV-1 RNA >= 50 c/mL at Baseline is defined as the time to first viral load value < 50 c/mL, irrespective of the ART regimen a participant was on when that occurred. Non parametric Kaplan-Meier method was used. Participants who withdrew for any reason without being suppressed were censored at date of withdrawal. Participants who have not been withdrawn and have not had viral suppression at time of the analysis were censored at last viral load date. Median time (i.e. time when 50% of participants have reached HIV-1 RNA < 50 c/mL) along with 95% CI is presented.
• Percentage of Participants Who Changed First Line Regimen of DTG + 3TC FDC Due to Baseline Laboratory Results or HIV-1 Resistance Mutation Results [ Time Frame: Up to Week 24 ]
  Percentage of participants who switched from first line regimen of DTG + 3TC FDC due to abnormal Baseline laboratory values or Baseline HIV-1 resistance mutation results are presented.
• Number of Participants With Treatment-emergent Genotypic Resistance [ Time Frame: Up to Week 24 ]
  Blood samples were collected for genotypic resistance testing post-Baseline when Confirmed Virologic Failure criteria were met or in other occasion as needed (e.g. at time of study withdrawal when HIV-1 RNA >= 400 c/mL). New mutations were tabulated by drug class: integrase strand transfer inhibitor (INSTI), non-nucleoside reverse transcriptase inhibitor (NNRTI), nucleoside reverse transcriptase inhibitor (NRTI) and protease inhibitor (PI). Number of participants with treatment-emergent resistance associated mutations to any class (INSTI, NNRTI, NRTI, PI) from post-Baseline genotypic resistance data up to Week 24 have been presented.
• Number of Participants With Any Serious Adverse Events (SAEs) and Any Common (>=2%) Non-serious Adverse Events (Non-SAEs) Under Treatment With DTG + 3TC FDC [ Time Frame: Up to Week 24 ]
  An adverse event is any untoward medical occurrence in a clinical study participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. An SAE is defined as any untoward medical occurrence that; results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, is a congenital anomaly/birth defect, other situations as judged by physician. Number of participants with any SAE and common (>=2%) non-SAEs are presented.
• Number of Participants With Maximum Post-Baseline Emergent Hematology Toxicities Under Treatment With DTG + 3TC FDC [ Time Frame: Up to Week 24 ]
  Blood samples were collected up to Week 24 visit for the analysis of hematology parameters-platelet count, neutrophils, hemoglobin and leukocytes Any abnormality was graded according to Division of Acquired Immunodeficiency Syndrome (DAIDS) toxicity scales from Grade 1 to 4 (1=Mild, 2=Moderate, 3=Severe, 4=Potentially life threatening). Higher grade indicates more severity. Only those participants with maximum post-Baseline emergent hematology toxicities in any of the hematology parameters have been presented.
• Number of Participants With Abnormal Clinical Chemistry Parameters Under Treatment With DTG + 3TC FDC [ Time Frame: Up to Week 24 ]
  Blood samples were collected up to Week 24 for the analysis of clinical chemistry parameters: alanine aminotransferase (ALT), albumin, aspartate aminotransferase AST), bilirubin, carbon dioxide (CO2), creatinine kinase (CK), creatinine, glomerular filtration rate (GFR) from creatinine adjusted for body surface area (BSA), glucose, hypercalcemia, hyperkalemia, hypernatremia, hypocalcemia, hypokalemia, hyponatremia and phosphate. Any abnormality was graded according to DAIDS toxicity scales from Grade 1 to 4 (1=Mild, 2=Moderate, 3=Severe, 4=Potentially life threatening). Only those participants with maximum post-Baseline emergent chemistry toxicities in any of the chemistry parameters have been presented.
• Number of Participants Who Discontinued the Study Treatment (DTG+3TC FDC) Due to AEs [ Time Frame: Up to Week 24 ]
  An adverse event is any untoward medical occurrence in a clinical study participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. Number of participants who discontinued the study treatment (DTG plus 3TC) due to AEs are presented.
• Number of Participants Who Discontinued the Study Treatment (DTG+3TC FDC) Due to Drug-related AEs [ Time Frame: Up to Week 24 ]
  An adverse event is any untoward medical occurrence in a clinical study participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. Number of participants who discontinued the study treatment (DTG+3TC FDC) due to drug-related AEs are presented.
• Change From Baseline in Cluster of Differentiation (CD4+) Cell Counts for Participants Under Treatment With DTG + 3TC FDC [ Time Frame: Baseline (Day 1) and Week 24 ]
  CD4+ cells are type of white blood cells that fight infection and as HIV infection progresses, the number of these cells decline. Blood samples were collected at specified time points to assess CD4+. It was evaluated by flow cytometry. Baseline value is defined as the latest pre-dose assessment (Day 1). Change from Baseline was defined as post-dose visit value minus Baseline value.
• Change From Baseline in CD4+/CD8+ Cell Count Ratio for Participants Under Treatment With DTG + 3TC FDC [ Time Frame: Baseline (Day 1) and Week 24 ]
  Blood samples were collected at specified time points to assess CD4+/CD8+ cell count ratio. It was assessed by flow cyclometry to evaluate the immunologic activity of DTG plus 3TC. Baseline value is defined as the latest pre-dose assessment (Day 1). Change from Baseline was defined as post-dose visit value minus Baseline value.
• Number of Participants Who Completed 24 Weeks on Study [ Time Frame: Week 24 ]
  Number of participants who completed 24 weeks on study are presented.
• Number of Participants Retained in Care for 24 Weeks on Study and Have HIV-1 RNA <200 c/mL [ Time Frame: Week 24 ]
  Number of participants retained in care for 24 weeks on study and have HIV-1 RNA <200 c/mL have been presented.

• Number of participants with plasma HIV-1 RNA less than 50 c/mL using the FDA Snapshot algorithm (not modified) [ Time Frame: At Week 24 and 48 ]
  Blood samples will be collected to assess the number of participants with plasma HIV-1 RNA less than 50 c/mL will be analyzed using the FDA Snapshot algorithm with no modification
• Number of participants with plasma HIV-1 RNA less than 50 c/mL using modified FDA Snapshot algorithm [ Time Frame: At Week 48 ]
  Blood samples will be collected to assess the number of participants with plasma HIV-1 RNA less than 50 c/mL will be analyzed using modified FDA Snapshot algorithm
• Time to suppression of HIV-1 RNA less than 50 c/mL [ Time Frame: Up to Week 48 ]
  Participants reaching viral suppression HIV-1 RNA less than 50 c/mL will be analyzed at given time points
• Number of participants who change first line regimen of DTG + 3TC due to Baseline laboratory or HIV-1 resistance mutation results [ Time Frame: Up to Week 48 ]
  Participants who change the first line regimen of DTG + 3TC due to Baseline laboratory or HIV-1 resistance mutation results will be analyzed at given time points
• Number of participants with treatment-emergent genotypic resistance to DTG and/or 3TC, or any other ART if treatment is modified, in participants meeting confirmed virologic failure criteria [ Time Frame: Up to Week 52 ]
  Blood samples will be collected for genotypic and phenotypic analyses at given time point. These may be analyzed by Monogram Biosciences using, but not limited to, their Standard PhenoSense and GenoSure testing methods for protease (PRO), reverse transcriptase (RT), and integrase assays. This assessment will be performed for participants meeting virologic failure criteria
• Number of participants with treatment-emergent phenotypic resistance to DTG and/or 3TC, or any other ART treatment, modified, in participants meeting confirmed virologic failure criteria [ Time Frame: Up to Week 48 ]
  Blood samples will be collected for genotypic and phenotypic analyses at given time point. This will be analyzed by Monogram Biosciences using, but not limited to, their Standard PhenoSense and GenoSure testing methods for protease (PRO), reverse transcriptase (RT), and integrase assays. This assessment will performed for participants with meeting confirmed virologic failure criteria
• Number of participants with adverse events (AEs) [ Time Frame: Up to Week 52 ]
  An AE is any untoward medical occurrence in a study participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product
• Severity of AEs [ Time Frame: Up to Week 52 ]
  Assessment of severity and intensity for each AE will be reported during the study. Intensity will be performed based on the division of acquired immune deficiency syndrome (AIDS) Table for Grading the Severity of Adult and Pediatric AEs (Division of AIDS [DAIDS] AE Grading Table)
• Number of participants with abnormal hematology parameters [ Time Frame: Up to Week 48 ]
  Blood sample will be collected to measure laboratory parameters such as platelet count, red blood cells (RBC) count, white blood cells (WBC) count (absolute), haemoglobin (Hb), hematocrit, mean corpuscular volume (MCV), mean corpuscular Hb (MCH), neutrophils, lymphocytes, monocytes, eosinophils, basophils
• Number of participants with abnormal chemistry parameters [ Time Frame: Up to Week 48 ]
  Blood sample will be collected to measure laboratory parameters such as blood urea nitrogen (BUN), creatinine, glucose, sodium, calcium, potassium chloride, total carbon dioxide (CO2), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, phosphate, protein, total bilirubin, direct bilirubin, albumin, glomerular Filtration rate (GFR)/creatinine clearance, cystatin-C
• Number of participants with abnormal urinalysis parameters [ Time Frame: Up to Week 48 ]
  Urine sample will be collected to measure urinalysis parameters such as specific gravity, power of hydrogen (pH), glucose, protein, blood and ketones by dipstick (with microscopic examination if blood or protein is abnormal), urine albumin/creatinine ratio, urine protein/creatinine ratio
• Number of participants who discontinued the treatment due to AEs [ Time Frame: Up to Week 48 ]
  Number of participants who will discontinue the treatment due to AEs will be analyzed
• Number of participants who discontinued the treatment due to drug-related AEs [ Time Frame: Up to Week 48 ]
  Number of participants who will discontinue the treatment due to drug-related AEs will be analyzed
• Change from Baseline in CD4+ cell counts [ Time Frame: Baseline (Day 1), Week 24 and 48 ]
  Blood samples will be collected at indicated time points
• Change from Baseline in CD4+/ cluster of differentiation 8 (CD8)+ ratio [ Time Frame: Baseline (Day 1), Week 24 and 48 ]
  Blood samples will be collected at indicated time points
• Number of participants who complete their visit [ Time Frame: At Weeks 24 and 48 ]
  Number of participants who will complete their visit at given time point will be analyzed
• Number of participants who complete their visit with HIV-1 RNA less than 200 c/mL [ Time Frame: At Weeks 24 and 48 ]
  Number of participants who complete their visit with HIV-1 RNA less than 200 c/mL will be analyzed at given time points

Inclusion Criteria:

• Eligible participants must be able to understand and comply with protocol requirements, instructions, and restrictions.
• Eligible participants must be likely to complete the study as planned.
• Eligible participants must be considered appropriate candidates for participation in an investigative clinical trial with oral medication (e.g. no active problematic substance abuse, acute major organ disease, or potential long-term work assignments out of the country).
• Participant must be more than or equal to 18 at the time of signing the informed consent.
• Participants must have a new and confirmed diagnosis of HIV-1 infection and are willing to initiate ART immediately (or, for those participants referred from another site, within 14 days of initial diagnosis at the external clinic/testing center).
• Participant must have an initial positive rapid HIV test and participant has a second positive confirmatory rapid HIV test, using a test kit from a different manufacturer than the first test or participant has been identified as HIV-1 infected using an FDA-approved 4th generation assay antigen/antibody combination immunoassay or 3rd generation immunoassay that detects and differentiates HIV-1 and HIV-2 antibodies; participant has a confirmatory HIV western blot or an HIV-1 RNA or participant has a positive FDA-approved 4th generation assay and a positive 3rd generation immunoassay that detects and differentiates HIV-1 and HIV-2 antibodies.
• Antiretroviral-naïve. Participants who received HIV post-exposure prophylaxis (PEP) or pre-exposure prophylaxis (PrEP) in the past are allowed as long as the last PEP/PrEP dose was more than 6 months from HIV diagnosis or there is documented HIV seronegativity at least 2 months after the last prophylactic dose and prior to the date of HIV diagnosis.
• Male and/or female participants.
• Participants who are female at birth are eligible to participate if at least one of the following conditions applies: Not pregnant [as confirmed by a negative urine human chorionic gonadotropin (hCG) test at Screening/Day 1.
• Pregnant and post the first trimester (the physician and patient should decide whether enrolling in this study is in the participants best interest during the consent process)
• Not a participant of childbearing potential (POCBP) or a POCBP agrees to follow the contraceptive guidance, is currently taking hormonal contraceptives and continues for at least 2 weeks after the last dose of study medication. Participants who are female at birth and who are in the following categories are not considered POCBP, premenarchal, premenopausal female with one of the following: documented hysterectomy, documented bilateral salpingectomy, documented bilateral oophorectomy or postmenopausal, a postmenopausal state is defined as no menses for 12 months without an alternative medical cause; a high follicle stimulating hormone (FSH) level in the postmenopausal range may be used to confirm a postmenopausal state in participants who are female at birth and not using hormonal contraception or hormonal replacement therapy (HRT); participants who are female at birth on HRT and whose menopausal status is in doubt will be required to use one of the non-hormonal highly effective contraception methods if they wish to continue their HRT during the study.
• Participants who are capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol.

Exclusion Criteria:

• Participants who are breastfeeding, plan to become pregnant or breastfeed during the study.
• Participants who are in their first trimester of pregnancy.
• HIV-1 drug resistance genotype test results are known prior to Screening/Day 1.
• Any evidence of an active Centers for Disease Control and Prevention (CDC) Stage 3 disease except for esophageal candidiasis and cutaneous Kaposi's sarcoma not requiring systemic therapy.
• Participants with known or suspected Hepatitis B infection.
• Participants with known or suspected severe hepatic impairment or unstable liver disease (as defined by the presence of ascites, encephalopathy, coagulopathy, hypoalbuminemia, esophageal or gastric varices, or persistent jaundice), cirrhosis, known biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones).
• Participants with known moderate to severe renal impairment (creatinine clearance less than 30ml/minute per 1.73 square meter);
• Participant with ongoing malignancy other than basal cell carcinoma, or resected, non-invasive cutaneous squamous cell carcinoma, or cervical, anal or penile intraepithelial neoplasia; other localized malignancies require agreement between the investigator and the Study Medical Monitor for inclusion of the participant.
• Participants who in the investigator's judgment, poses a significant suicidality risk.
• Participants with any pre-existing physical or mental condition which, in the opinion of the Investigator, may interfere with the participant's ability to comply with the dosing schedule and/or protocol evaluations or which may compromise the safety of the participant.
• Participants with substance abuse disorders or social restraints that the Investigator considers to be possible deterrents to successful initiation of ART.
• Participants with history or presence of allergy or intolerance to the study drugs or their components.
• Participants with treatment with any of the following agents within 28 days of the first dose of study treatment, radiation therapy, cytotoxic chemotherapeutic agents, any systemic immune suppressant.
• Participants receiving any prohibited medication and who are unwilling or unable to switch to an alternate medication.
• Exposure to an experimental drug or experimental vaccine within either 28 days, 5 half-lives of the test agent, or twice the duration of the biological effect of the test agent, whichever is longer, prior to the first dose of study treatment.