Efficacy, Safety, and Tolerability of Switching From Bictegravir/Emtricitabine/Tenofovir Alafenamide to Dolutegravir/Lamivudine Among Adults With Virologically Suppressed HIV: The DYAD Study.

Background: In TANGO and SALSA, switching to dolutegravir/lamivudine (DTG/3TC) was noninferior to continuing a baseline regimen among adults who were treatment experienced, although few switched from bictegravir (B) / emtricitabine (F) / tenofovir alafenamide (TAF). Here, we present the efficacy and safety of switching to DTG/3TC as compared with continuing with B/F/TAF among adults with virologic suppression.

Methods: DYAD is an open-label clinical trial that randomized adults with HIV-1 RNA <50 copies/mL and no prior virologic failure (2:1) to switch to once-daily fixed-dose DTG/3TC or maintain B/F/TAF. The primary end point is the proportion with HIV-1 RNA ≥50 copies/mL at week 48 (Food and Drug Administration Snapshot algorithm, intention-to-treat exposed population, 6% noninferiority margin).

Results: Overall, 222 adults were randomized (16% women, 51% aged ≥50 years, 28% Black). At week 48, 6 (4%) with DTG/3TC and 5 (7%) with B/F/TAF had HIV-1 RNA ≥50 copies/mL (treatment difference, -2.8%; 95% CI, -11.4% to 3.1%), meeting noninferiority criteria. Through week 48, 18 participants (12 with DTG/3TC, 6 with B/F/TAF) met confirmed virologic withdrawal (CVW) criteria, and 2 of 18 had resistance: 1 with B/F/TAF developed M184M/I and G140G/S at week 12, and 1 with DTG/3TC had M184V at week 12. One participant with DTG/3TC and non-CVW developed M184V and K65R at week 12. Drug-related adverse events (AEs) and withdrawals due to AEs occurred in 31 (21%) and 6 (4%) participants with DTG/3TC and 2 (3%) and 0 participants with B/F/TAF, respectively.

Conclusions: Switching to DTG/3TC was noninferior to continuing B/F/TAF among adults with virologic suppression at week 48. Drug-related AEs and withdrawals were higher in the DTG/3TC arm, which is likely consistent with the open-label nature of this switch study.