For nine months, Timothy Andrews lived with a kidney that came not from a human donor, but from a genetically engineered pig. After the pig kidney allowed him to avoid dialysis for 271 days, he received a transplant from a human donor. This represents the first documented case in which an animal organ transplant served as a temporary solution until a human organ became available.
Andrews, who was 66 at the time of the procedure, suffered from end-stage kidney failure and received the pig kidney on January 25, 2025, at Mass General Brigham medical center in Boston. The kidney began functioning immediately after transplantation, enabling him to stop dialysis treatments for nine months, the longest period documented to date in a living person who received a pig kidney.
The case was published this week in the medical journal The Lancet and marks significant progress in xenotransplantation, the field of transplanting organs from animals into humans. Researchers believe this demonstrates for the first time that a pig kidney can serve as a medical "bridge": while it may not permanently replace a human kidney, it could give patients valuable time, free them from dialysis, and improve their physical condition until a suitable human kidney is found.
