Efficacy and safety of switch to bictegravir/emtricitabine/tenofovir alafenamide from dolutegravir/abacavir/lamivudine: Results from an open-label extension of a phase 3 randomized, double-blind, multicenter, active-controlled, non-inferiority study.

BACKGROUND

The phase 3 randomized, active-controlled GS-US-380-1844 (NCT02603120) study evaluated switching to the single-tablet regimen bictegravir, emtricitabine, and tenofovir alafenamide (B/F/TAF) from dolutegravir (DTG), abacavir (ABC), and lamivudine (3TC) among people with HIV-1. Previously, results from the 48-week double-blind phase showed that switching to B/F/TAF was noninferior to remaining on DTG/ABC/3TC and that B/F/TAF was well tolerated. Here, we show the long-term safety and efficacy of switching to B/F/TAF from DTG/ABC/3TC among people with HIV-1.

METHODS

Participants were virologically suppressed people with HIV-1 (HIV-1 RNA <50 copies/mL for ≥ 3 months prior to screening) receiving DTG/ABC/3TC at baseline. Participants were randomized 1:1 to switch to B/F/TAF or remain on DTG/ABC/3TC. Following 48 weeks of treatment with B/F/TAF or DTG/ABC/3TC in the double-blind phase, participants had the option to enter an open-label extension phase, during which they received B/F/TAF. Virologic, immunologic, and safety outcomes during treatment with B/F/TAF through the open-label extension up to 168 weeks, including preexisting and treatment-emergent resistance, were analyzed.

RESULTS

Among 547 participants in the all-B/F/TAF analysis set, virologic suppression (HIV-1 RNA < 50 copies/mL) was maintained in 99% to 100% of participants up to 168 weeks into B/F/TAF treatment, including in those with preexisting resistance; no treatment-emergent resistance was detected. CD4 cell counts remained stable during B/F/TAF treatment, with median (interquartile range) changes from baseline of -17 (-120, 65) cells/µL at week 48 and -9 (-100, 108) cells/µL at week 96. Safety and tolerability findings were consistent with previously reported findings up to week 48; most drug-related adverse events were grade 1 or 2 in severity; no new safety signals were identified.

CONCLUSION

Switching to B/F/TAF from DTG/ABC/3TC was associated with continued high rates of virologic suppression up to week 168, with no treatment-emergent resistance. B/F/TAF was well tolerated throughout the study period.