The results stem from the firm's phase III Blaze-2 COVID-19 prevention trial, which was conducted in partnership with the U.S. National Institute of Allergy and Infectious Diseases (NIAID). The study enrolled 965 residents and staff at skilled nursing and assisted living facilities across the U.S. Some participants tested negative for SARS-CoV-2 at baseline while others did not. However, all participants were randomized to receive either 4,200 mg of bamlanivimab or a placebo.

After eight weeks of follow-up, researchers found a significantly lower frequency of symptomatic COVID-19 in the bamlanivimab treatment arm versus a placebo. The results suggest that residents randomized to bamlanivimab have up to an 80% lower risk of contracting COVID-19 versus the residents in the same facility randomized to a placebo.

Four deaths were attributed to COVID-19 and occurred in the placebo arm while no deaths were attributed to COVID-19 in the bamlanivimab arm. Over the entire trial, 16 deaths were reported, including deaths not related to COVID-19. All deaths were residents -- 11 in the placebo arm and five in the bamlanivimab arm.

BLAZE-2 is an ongoing open-label trial. The full results of the trial will be presented at a future medical congress and submitted for publication in a peer-reviewed clinical journal, Eli Lilly said.