U.S. hospitals, weighing high demand and tight supplies, said they may limit use of a new Eli Lilly and Co. antibody drug to COVID-19 patients with multiple risk factors for serious illness or to those whose immune systems have not begun to fight the infection. The treatment, bamlanivimab, was given U.S. emergency use authorization (EUA) last week by the FDA for helping newly-diagnosed, high-risk patients avoid hospitalization.