The first clinical trial is getting underway to see if transplanting pig kidneys into people might really save lives. United Therapeutics, a producer of gene-edited pig kidneys, announced Monday that the study’s initial transplant was performed successfully at NYU Langone Health. It’s the latest step in the quest for animal-to-human transplants. A second U.S. company, eGenesis, is preparing to begin a similar trial in the coming months. A handful of experiments led up to these more rigorous studies. The longest-lasting known so far was 271 days, when a New Hampshire man resumed dialysis as his declining pig kidney was removed.