A randomized, placebo-controlled clinical trial of bamlanivimab and etesevimab together in high-risk ambulatory patients with COVID-19 and validation of the prognostic value of persistently high viral load.

BACKGROUND: Based on interim analyses and modelling data, lower doses of bamlanivimab and etesevimab together (700mg/1400mg) were investigated to determine optimal dose and expand availability of treatment. METHODS: This Phase 3 portion of the BLAZE-1 trial characterized the effect of bamlanivimab with etesevimab on overall patient clinical status and virologic outcomes in ambulatory patients ≥12 years old, with mild-to-moderate COVID-19, and ≥1 risk factor for progressing to severe COVID-19 and/or hospitalization. Bamlanivimab and etesevimab together (700mg/1400mg) or placebo were infused intravenously within 3 days of patients' first positive COVID-19 test. RESULTS: 769 patients were infused (median age [range]; 56.0 years [12, 93], 30.3% of patients ≥65 years of age and median duration of symptoms; 4 days). By day 29, 4/511 patients (0.8%) in the antibody treatment group had a COVID-19-related hospitalization or any-cause death, as compared with 15/258 patients (5.8%) in the placebo group (Δ[95% CI]=-5.0 [-8.0, -2.1], p<0.001). No deaths occurred in the bamlanivimab and etesevimab group compared with 4 deaths (all COVID-19-related) in the placebo group. Patients receiving antibody treatment had a greater mean reduction in viral load from baseline to Day 7 (Δ[95% CI]=-0.99 [-1.33, -0.66], p<0.0001) compared with those receiving placebo. Persistently high viral load at Day 7 correlated with COVID-19-related hospitalization or any-cause death by Day 29 in all BLAZE-1 cohorts investigated. CONCLUSIONS: These data support the use of bamlanivimab and etesevimab (700mg/1400mg) for ambulatory patients at high risk for severe COVID-19. Evolution of SARS-CoV-2 variants will require continued monitoring to determine the applicability of this treatment.