In this Saturday, March, 14, 2020 photo provided by Regeneron, , left, and members of the company's infectious disease team pose for a photo as they celebrate their first discovery of potential antibodies to treat COVID-19. They had spent weeks drawing blood from early survivors across the globe and from mice with human-like immune systems - all to test thousands of potential treatments. (Regeneron via AP)

In this Friday, March 13, 2020 photo provided by Regneron, members of the Infectious Disease team celebrate at their lab in New York state after confirming cells from Singapore are viable and that some make antibodies that bind to the coronavirus, suggesting they may have the potential to block it. (Regeneron via AP)

In this Saturday, March, 14, 2020 photo provided by Regeneron, members of the company's infectious disease team pose for a photo as they celebrate their first discovery of potential antibodies to treat COVID-19. They had spent weeks drawing blood from early survivors across the globe and from mice with human-like immune systems - all to test thousands of potential treatments. (Regeneron via AP)

FILE - In this undated image from video provided by Regeneron Pharmaceuticals on Friday, Oct. 2, 2020, scientists work with a bioreactor at a company facility in New York state, for efforts on an experimental coronavirus antibody drug. Antibodies are proteins the body makes when an infection occurs; they attach to a virus and help the immune system eliminate it. (Regeneron via AP)

In this undated image from video provided by Regeneron Pharmaceuticals on Friday, Oct. 2, 2020, vials are inspected at the company's facilities in New York state, for efforts on an experimental coronavirus antibody drug. Antibodies are proteins the body makes when an infection occurs; they attach to a virus and help the immune system eliminate it. (Regeneron via AP)