Pig kidney functions in US patient for record 271 days

A genetically modified pig kidney functioned inside a US man for 271 days, setting a new record for xenotransplantation and giving doctors further evidence that animal organs might temporarily help patients awaiting human donors.

The patient, Tim Andrews, had end-stage kidney failure caused by type 2 diabetes. He was 66 when doctors performed the experimental transplant on January 25, 2025. The kidney began working immediately and continued providing renal function until doctors removed it in October 2025.

The organ ultimately stopped functioning. Andrews returned to dialysis for 82 days before receiving a human donor kidney in January 2026. His new kidney is currently working properly.

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Doctors at Mass General Brigham view the result as support for using pig kidneys as an interim solution. Andrews had been told that he might wait about seven years to rise high enough on the transplant list, while average survival for dialysis patients is estimated at about five years.

For Andrews, the procedure offered time when a human transplant remained uncertain. “Hope is the most important thing,” he said, describing the chance to leave the dialysis machine and live his life. Researchers consider pigs suitable for xenotransplantation because their organs are close in size to human organs and the animals can be raised under controlled conditions. Genetic modification remains necessary because the human immune system can identify a pig organ as foreign and rapidly attack it.

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Hope is the most important thing: the chance to get off the dialysis machine and live your life.