Regeneron Pharmaceuticals has begun a phase 3 clinical trial in the U.S. of its antibody cocktail REGN-COV2 for the prevention of COVID-19 infections.

The trial is being conducted with the National Institutes for Allergy and Infectious Diseases and plans to enroll 2,000 patients across 100 sites.

The company has also launched two phase 2/3 trials evaluating the cocktail’s ability to treat patients already infected with COVID-19.