Increasing data support use of certain two-drug antiretroviral (ART) regimens for maintenance therapy for select HIV-infected patients suppressed on a standard ART regimen (NEJM JW Infect Dis Jan 2018). Experience with two-drug ART regimens for initial HIV therapy has been less favorable. In this pilot study, the two-drug regimen dolutegravir + lamivudine (3TC) was evaluated in treatment-naive HIV-infected patients without active hepatitis B infection who had HIV RNA levels ≥1000 and <500,000 copies/mL. The planned primary endpoint was the proportion with HIV RNA <50 copies/mL at week 24.

The study enrolled 120 persons at 26 sites in the U.S. (median HIV RNA, 4.6 log10 copies/mL; median CD4 count, 387 cells/mm³; 87% male; 72% nonwhite). At 24 weeks, 108 (90%) of the participants had HIV levels <50 copies/mL; results were similar for those with HIV RNA >100,000 or ≤ 100,000 copies/mL. Three participants met criteria for virologic failure; all had undetectable dolutegravir levels at ≥1 time points and one had M184V and R263R/K integrase mutations identified at time of failure. The regimen was well tolerated, with no treatment discontinuations due to adverse effects. The authors conclude that these results support further evaluation in select treatment-naive patients planned in the currently enrolling phase 3 studies.