FDA clears United Therapeutics for human trials of pig-to-human kidney transplants. Trial involves gene-edited pig kidneys for patients with end-stage renal disease. Study aims to provide alternative for 500,000 Americans on dialysis.

The second person ever has received a transplant with a genetically modified pig kidney.

The FDA will allow two biotechnology companies to run clinical trials: United Therapeutics and eGenesis. United Therapeutics Corporation will start with six patients but could grow its trial to include up to 50 individuals, while eGenesis plans to begin with three patients.

The U.S. Food and Drug Administration has approved the first-ever clinical trials testing pig kidney transplants in people with kidney failure, marking a major step forward in cross-species transplantation.

The first clinical trials using organs from genetically modified pigs offer hope to patients with kidney failure, who face a long wait for human organ transplants.

United Therapeutics has scored a regulatory green light to start clinical trials for its genetically modified pig kidneys to be transplanted into humans. It's as significant for the medical community as it is for the business.