Shares of the Indianapolis drugmaker at last check were off 0.8% to $130.85.
Under the terms of the agreement, Lilly will distribute vials of the drug, bamlanivimab, also referred to as LY-CoV555, to the government if the Food and Drug Administration grants an emergency-use authorization.
Earlier this month, Eli Lilly filed for emergency use authorization of LY-CoV555 followed trial data showing that the experimental antibody met both primary and secondary endpoints.
The U.S. has the option to purchase up to an additional 650,000 vials through next June.
The federal government and state health departments are developing a government allocation program for LY-CoV555.
Eli Lilly is partnering with Operation Warp Speed, the White House-led effort to quickly secure supply of Covid-19 vaccines and therapeutics, and with a national distributor to finalize distribution plans and shipping preparations, should it receive emergency authorization.
The company is developing the treatment with the Vancouver biotech AbCellera Biologics.
Eli Lilly said it expects to make as many as one million doses of bamlanivimab 700mg by the end of 2020 – with 100,000 doses ready to ship within days of authorization – for use around the world.
The company said the supply of its antibody therapy is expected to increase substantially beginning in the first quarter, as additional manufacturing resources come online throughout the year.
The news of the sale comes a day after Eli Lilly posted weaker-than-expected third-quarter earnings and lowered part of its full-year profit guidance. Sales of its Trulicity diabetes treatment had slowed and costs linked to its coronavirus treatment jumped.