GSK’s ViiV Healthcare presented results from the Phase III GEMINI 1 & 2 studies, assessing the safety and efficacy of a two-drug regimen (2DR) of dolutegravir (DTG) and lamivudine (3TC) compared to a three-drug regimen of dolutegravir and two nucleoside reverse transcriptase inhibitors (NRTIs), tenofovir disoproxil fumarate/emtricitabine (TDF/FTC), in treatment-naïve, HIV-1 infected adults. The studies are designed to demonstrate the non-inferior efficacy, safety and tolerability of once-daily dolutegravir and lamivudine compared to once-daily dolutegravir and the fixed-dose combination of TDF/FDC. GEMINI 1 (204861) and GEMINI 2 (205543) are duplicate, Phase III, randomized, double-blind, multicenter, parallel group, non-inferiority studies. These studies enrolled naïve adult participants with baseline HIV-1 viral loads up to 500,000 copies per ml. The studies met their primary endpoint for non-inferiority based on plasma HIV-1 RNA <50c/mL, a standard measure of HIV control, at Week 48. Results show broadly consistent results for virus suppression across individuals with higher viral load. Pooled results show that the most common (≥5 percent) adverse events across the studies were headache, diarrhea and nasopharyngitis in both arms (DTG + 3TC arm: 10 percent, 9 percent, and 8 percent, respectively, DTG + TDF/FTC: 10 percent, 11 percent, and 11 percent). Rates of virologic failure were ≤1 percent across all arms of the study. Drug-related adverse events were less frequent in patients on the DTG/3TC regimen (126/716, 18 percent), compared with those on the DTG + TDF/FTC regimen (169/717, 24 percent).