Genetically modified pig kidney bridges man to human transplant

The first known patient to transition from an animal kidney to a human donor organ was a man with end-stage kidney disease who lived nine months without dialysis after receiving a genetically modified pig kidney, researchers said.

At Massachusetts General Hospital in Massachusetts in January 2025, Tim Andrews, 66, received the pig kidney. The organ was functional for 271 days, allowing him to avoid dialysis while waiting for a human transplant, according to information released by Mass General Brigham and a study published in The Lancet.

Eventually the pig kidney developed damage to blood vessels and failed. Doctors removed it, and Andrews got a human kidney transplant in January 2026. The case, according to researchers, offers preliminary evidence that genetically engineered pig kidneys could serve as a temporary “bridge” for patients waiting for human organs.

Andrews said the transplant was a “miracle” and called the change in his condition life-altering.

“We know that the best treatment option for patients with end-stage kidney disease who have developed renal failure is transplantation,” said Andrews. “But we simply don’t have enough human organs to transplant in a timely manner.”

The kidney had been genetically modified to reduce immune rejection and delete pig viruses. No pig viruses or other pig pathogens were found during the Andrews treatment, according to researchers.

The results could advance xenotransplantation, as researchers look for alternatives to the shortage of human donor organs, though more clinical trials are needed.