One approach to this technology is the creation of a transgenic mammal that can produce the biopharmaceutical in its milk (or blood or urine). Once an animal is produced, typically using the pronuclear microinjection method, it becomes efficacious to use cloning technology to create additional offspring that carry the favorable modified genome.[17] In February 2009 the US FDA granted marketing approval for the first drug to be produced in genetically modified livestock.[18] The drug is called ATryn, which is antithrombin protein purified from the milk of genetically modified goats.