The company on Tuesday said the trial's Data Safety Monitoring Board (DSMB), an independent group of medical experts who monitor clinical trials, recommended the pause, a Lilly spokesperson said in a statement.
"Lilly is supporting the decision made by DSMB cautiously to ensure the safety of the patients participating in this study," said the statement.
Neither Eli Lilly nor the National Institute of Allergy and Infectious Diseases (NIAID), which is sponsoring the trial, have described the safety issue that prompted the decision to pause the study.
The study is one of several being conducted in the United States to test the use of the antibody treatment in various settings.
Eli Lilly announced earlier this month that new data showed that combination therapy with two of Lilly's SARS-CoV-2 neutralizing antibodies reduced viral load, symptoms and COVID-related hospitalization and emergency room visits.
Eli Lilly's decision to pause trial followed the announcement of US pharmaceutical company Johnson & Johnson, which announced late Monday it had paused its COVID-19 vaccine trial because one of its participants had become sick.
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