A genetically modified pig kidney has functioned inside a US man for 271 days, setting a new record for the longest time such an organ has worked in a human body.

The patient, 66-year-old Tim Andrews, received the transplant at Massachusetts General Hospital in January 2025.

Andrews had developed end-stage kidney disease linked to type 2 diabetes and was on dialysis while waiting for a human donor kidney. The pig kidney transplant gave him a temporary break from the machine and a chance to live more normally during that period.

The organ, taken from a specially modified pig, began working immediately after the operation. Doctors later removed it in October 2025 after it showed signs of failure. Andrews then returned to dialysis for 82 days before receiving a human donor kidney in January 2026, which has been functioning well.

The donor pig had undergone extensive genetic changes designed to make its organs more compatible with the human body and reduce the risk of rejection or infection. Doctors said the kidney initially faced some rejection, which was managed with medication, but later developed damage that led to its removal.

Researchers see the case as both a step forward and a reminder of remaining challenges in xenotransplantation. They hope genetically modified pig organs could one day serve as a temporary bridge for patients waiting for human donors, helping them avoid long periods on dialysis.

Photo credit: Punch Healthwise