Man receives human kidney transplant after surviving 271 days with gene-edited pig organ

Andrews was 66, had end-stage kidney disease, no suitable living donor, and a long anticipated wait time for a deceased donor when he underwent surgery in 2025 to receive a kidney from a pig.

Doctors at Massachusetts General Hospital made history by giving a man a human kidney transplant months after successfully transplanting a porcine one, according to a study by Mass General Brigham published in The Lancet on Thursday.

Tim Andrews was 66, had end-stage kidney disease, had no suitable living donor, and had a long anticipated wait time for a deceased donor when he underwent surgery in 2025 to receive a kidney from a pig instead of a human.

The kidney functioned within Andrews' body without the need for dialysis for 271 days, the longest time on record for a porcine kidney transplant. Eventually, the kidney had to be removed, and Andrews returned to dialysis for 82 days before undergoing human kidney transplantation.

Extensive research has been done on xenotransplantation, the process of transplanting an organ from an animal to a human to address organ shortages. Pigs are often considered candidates because their organs are similar in size to humans'. However, humans are extremely sensitive to even other human organs, which must be carefully matched so the body does not recognize them as foreign and attack them.

To make xenotransplantation possible, scientists have begun genetically modifying pigs to make their organs more compatible with humans.

The kidney Andrews received was gene-edited and initially showed signs of rejection. Andrews' doctors were able to resolve the initial rejection symptoms through the use of immunosuppression treatment, but even this could only be effective for six months.

A bacterial infection reduced the immunosuppression, although researchers clarified that the infection was unrelated to the transplant and that no pathogen had been transmitted from the pig, another concern with xenotransplantation.

Kidney served as a bridge to human transplantation

Eventually, after 271 days, the kidney was removed, and Andrews returned to dialysis before receiving a human transplant almost a year after his porcine one.

The transplant was successful, and monitoring identified no negative effects from the porcine organ on Andrews' ability to tolerate the human one.

Scientists emphasized the importance of Andrews' case as proof that xenotransplantation can serve as a temporary bridge solution for patients until a human organ becomes available.