Tarrytown-based Regeneron reports that it anticipates recording approximately $260 million in sales of its antiviral monoclonal antibody cocktail REGEN-COV U.S. to the U.S. government for the first quarter of 2021. Continuing deliveries of the drug to the government are scheduled for the second quarter and, according to the company, the government is obligated to buy all finished doses supplied by June 30, up…