A Phase IIb Study to Evaluate a Long-Acting Intramuscular Regimen for Maintenance of Virologic Suppression (Following Induction With an Oral Regimen of GSK1265744 and Abacavir/Lamivudine) in Human Immunodeficiency Virus Type 1 (HIV-1) Infected, Antiretroviral Therapy-Naive Adult Subjects

This study is a Phase IIb, randomized, multicentre, parallel group, open-label, study having an overall objective to evaluate the antiviral activity, tolerability, and safety of two intramuscular (IM) dosing regimens of GSK744 LA plus TMC278 LA, relative to GSK744 30 milligram (mg) plus Abacavir/Lamivudine (ABC/3TC) given orally once daily (QD), in HIV-1 infected antiretroviral-naïve subjects. GSK744 is the oral formulation of GSK1265744 (cabotegravir), GSK744 LA is the long acting injectable formulation of GSK1265744 and TMC278 LA is the long acting injectable formulation of TMC278. The study will consist of three parts: an Induction Period, Maintenance Period and Extension Period. There is also a Long-Term Follow Up Period for subjects who withdraw from the study and have received at least one dose of GSK744 LA and / or TMC278 LA. In the Induction Period, eligible subjects will receive a combination of an oral regimen of 30 mg of GSK744 and 600/300 mg of ABC/3TC, once daily for 20 weeks. In the Maintenance Period, eligible subjects will be randomized 2:2:1 at Day 1 to receive an IM regimen of GSK744 LA 400 mg + TMC278 LA 600 mg every 4 weeks for 96 weeks (Q4W), an IM regimen of GSK744 LA 600 mg + TMC278 LA 900 mg every 8 weeks for 96 weeks (Q8W), or to continue on the oral Induction Period regimen of GSK744 30 mg + ABC/3TC once daily for 96 weeks (or 104 weeks if continuing on to the Extension Period). The Extension Period will allow for a collection of longer term efficacy and safety and tolerability data from subjects receiving GSK744 LA and TMC278 LA. The study will involve sufficient subjects at screening in order to ensure a total of approximately 265 subjects at the beginning of the Induction Period and approximately 225 subjects randomized into the Maintenance Period.