A kidney transplanted from a pig has worked inside a patient for 271 days, the longest on record, say US doctors.
Doctors said the animal organ was used as a temporary “bridge” while the man waited for a transplant from a human donor.
Tim Andrews, who had end-stage kidney disease, was 66 when he received the pig kidney in the US in January 2025. He lived successfully with the genetically edited organ for 271 days before moving to short-term dialysis and receiving a donor human kidney.
It is the longest dialysis-free survival after a pig-kidney transplant in a living human and the first transition from pig-to-human kidney transplantation, doctors have said.
The team from Mass General Brigham in the US published their findings in the Lancet medical journal.
Lead author Dr Leonardo Riella, from the Centre for Transplantation Sciences at Mass General Brigham, said: “The organ shortage is the greatest crisis we have right now in transplantation.
“We know that the best treatment option for patients with end-stage kidney disease who have developed renal failure is transplantation, but we simply don’t have enough human organs to transplant in a timely manner.
“Our vision is that xenotransplantation could help address this gap, initially as a bridge to get patients off dialysis while they wait for a human donor kidney and potentially, as we establish long-term safety and durability, as a destination therapy in its own right.”
Another pig-kidney transplant to a living human was undertaken in 2024 at Massachusetts General Hospital, where the patient survived 52 days before dying from heart issues unrelated to the transplant.
Dr Rommel Ravanan, a consultant nephrologist and chief medical officer for the UK’s NHS Blood and Transplant, said the US and China have reported several similar transplants since 2022.
He said: “Advances in genetics technology enable teams to ‘knock out’ some of the pig genes, so the human body is less able to recognise the organ was different.