Tenofovir alafenamide plus emtricitabine versus abacavir plus lamivudine for treatment of virologically suppressed HIV-1-infected adults: a randomised, double-blind, active-controlled, non-inferiority phase 3 trial

BACKGROUND: Abacavir and tenofovir alafenamide offer reduced bone toxicity compared with tenofovir disoproxil fumarate. We aimed to compare safety and efficacy of tenofovir alafenamide plus emtricitabine with that of abacavir plus lamivudine. METHODS: In this randomised, double-blind, active-controlled, non-inferiority phase 3 trial, HIV-1-positive adults (≥18 years) were screened at 79 sites in 11 countries in North America and Europe. Eligible participants were virologically suppressed (HIV-1 RNA <50 copies per mL) and on a stable three-drug regimen containing abacavir plus lamivudine. Participants were randomly assigned (1:1) by a computer-generated allocation sequence (block size 4) to switch to fixed-dose tablets of tenofovir alafenamide (10 mg or 25 mg) plus emtricitabine (200 mg) or remain on abacavir (600 mg) plus lamivudine (300 mg), with matching placebo, while continuing to take the third drug. Randomisation was stratified by the third drug (boosted protease inhibitor vs other drug) at screening. Investigators, participants, and study staff giving treatment, assessing outcomes, and collecting data were masked to treatment group. The primary endpoint was the proportion of participants with virological suppression (HIV-1 RNA