(1122) Switching to Dolutegravir/lamivudine (DTG/3TC) Is Non-inferior to Continuing Tenofovir Alafenamide (TAF)-Based Regimens at Week 196: TANGO Subgroup Analyses

Objectives: Switching to DTG/3TC from 3- or 4-drug TAF-based regimens showed durable high efficacy in virologically suppressed adults with HIV-1 through Week (W) 196 in the TANGO study. To further investigate DTG/3TC efficacy in TANGO participants who switched to DTG/3TC on Day 1 and those who switched at W148, we present Snapshot virologic response by subgroup based on demographic and baseline disease characteristics and baseline third agent class.

Methods: TANGO is an open-label, multi-center, randomized, phase 3 study assessing efficacy and safety of switching to DTG/3TC vs continuing TAF-based regimens. Adults with HIV-1 RNA < 50 c/mL on TAF-based regimens for >6 months without prior virologic failure or documented NRTI or INSTI resistance were eligible. Participants were stratified by baseline third agent class and randomized 1:1 to switch to DTG/3TC on Day 1 (early-switch [ES] group) or continue TAF-based regimens for 144 weeks. Participants who continued TAF-based regimens and maintained virologic suppression at W144 switched to DTG/3TC at W148 (late-switch [LS] group).

Results: At W196, TANGO included 369 ES group and 298 LS group participants treated with DTG/3TC for 196 and 48 weeks, respectively. Few ES participants (3/369 [ < 1%]; 95% CI, 0.0%-1.7%) and 0/298 (95% CI, 0.0%-0.0%) LS participants had HIV-1 RNA ≥50 c/mL at W196 by Snapshot analysis (ITT-E). Overall ES group and LS group Snapshot virologic response rates were consistent with rates across their respective subgroups related to demographic characteristics, baseline disease characteristics, and baseline third agent class at W196. Safety was consistent across subgroups within ES and LS groups. Confirmed virologic withdrawal criteria were met by 1/369 ( < 1%) ES and no LS participants through W196, with no resistance observed.

Conclusions: These results support that switching to DTG/3TC from TAF-based regimens effectively maintains virologic suppression across different demographic and baseline characteristic subgroups at 48 and 196 weeks.