Abstract
BACKGROUND: Doravirine/islatravir is an investigational regimen that is being studied for human immunodeficiency virus type 1 (HIV-1) treatment. METHODS: In this phase 3, double-blind, double-dummy trial (ClinicalTrials.gov NCT04233879), previously untreated adults with HIV-1 were randomized (1:1) and stratified by HIV-1 RNA (≤/>100 000 copies/mL) and CD4 count (≥200 cells/µL) to doravirine/islatravir (100/0.75 mg) or bictegravir/emtricitabine/tenofovir alafenamide (50/200/25 mg) orally once-daily (primary endpoint: percentage of participants with HIV-1 RNA <50 copies/mL at week 48; US Food and Drug Administration snapshot, 10% noninferiority margin). RESULTS: Overall, 597 participants were treated; enrollment stopped early due to decreases in CD4 and lymphocyte counts observed in other islatravir studies. Doravirine/islatravir was noninferior to bictegravir/emtricitabine/tenofovir alafenamide: 265 of 298 (88.9%) versus 264 of 299 (88.3%) had HIV-1 RNA <50 copies/mL (difference, 0.5%; 95% confidence interval [CI]: -4.7, 5.6). Mean change from baseline in CD4 count was +182 and +234 cells/µL (difference, -50; 95% CI: -79, -21) with doravirine/islatravir versus bictegravir/emtricitabine/tenofovir alafenamide. Mean change in lymphocyte count was 0.01 and 0.21 × 109/L (difference, -0.20; 95% CI: -0.30, -0.10). Adverse events (AEs) occurred in 90.6% and 87.3% of participants, with coronavirus disease 2019 being most common (14.1%, 16.4%). Treatment-related AEs were similar (28.9%, 25.8%). AEs that led to discontinuations were higher with doravirine/islatravir (8.7%, 3.7%) due to protocol-specified criteria that required discontinuation for decreased CD4 and lymphocyte counts. CONCLUSIONS: Doravirine/islatravir (100/0.75 mg) once-daily was noninferior to bictegravir/emtricitabine/tenofovir alafenamide through week 48 for initial HIV-1 treatment. Due to decreases in CD4 and lymphocyte counts, development of this dose of doravirine/islatravir was stopped. CLINICAL TRIALS REGISTRATION: NCT04233879.