The FDA on Feb 6 approved Atryn, the first drug produced by animals that have been given a human gene. Atryn, developed by GTC Biotherapeutics Inc. from the milk of a genetically altered goat, combines human DNA for antithrombin with goat DNA in such a way that the goat"s milk glands excrete human antithrombin. The drug will be used to treat patients with a rare blood-clotting disorder known as hereditary antithrombin deficiency.