Massachusetts General Hospital said Thursday that it’s the first time a genetically modified pig kidney has been transplanted into a living person. Previously, pig kidneys have been temporarily transplanted into brain-dead donors. Also, two men received heart transplants from pigs, although both died within months.

The patient, Richard “Rick” Slayman of Weymouth, Massachusetts, is recovering well from the surgery last Saturday and is expected to be discharged soon, doctors said Thursday.