Medical Breakthrough: Pig Kidney Keeps US Patient Alive Without Dialysis for 271 Days

A genetically edited pig kidney has functioned successfully inside a living human patient for 271 days, enabling a 66-year-old American man with end-stage kidney disease to stay off dialysis for about nine months before he eventually received a human donor kidney.

The achievement, described by Doctors as the longest recorded dialysis-free survival after a pig-kidney transplant in a living human, marks a significant development in the race to use animal organs to address the global shortage of human donor kidneys.

According to researchers from Mass General Brigham in the United States, the patient, Tim Andrews, was 66 when he received the genetically modified pig kidney in January 2025.

The transplanted organ continued functioning for 271 days, during which Andrews successfully remained without dialysis. He was subsequently placed on short-term dialysis before receiving a kidney from a human donor.

Doctors said the pig kidney was used as a temporary “bridge”, allowing Andrews to remain off dialysis while waiting for a suitable human kidney.

Lead author Dr Leonardo Riella, from the Centre for Transplantation Sciences at Mass General Brigham, said the development could help tackle the shortage of organs available for transplantation.

“The organ shortage is the greatest crisis we have right now in transplantation,” Riella said.

He noted that although transplantation remains the best treatment option for patients with end-stage kidney disease, the number of available human organs is far below what is required.

“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,” he said.

Global Mirror News gathered that the procedure is part of a rapidly developing field known as xenotransplantation, which involves transplanting organs, tissues or cells from animals into humans.

Scientists have increasingly focused on pigs because their organs are considered relatively compatible with humans in terms of size and biological characteristics. However, one of the biggest obstacles has been the human immune system, which can recognise animal organs as foreign and attack them.

Advances in genetic engineering have enabled researchers to modify pig organs by removing or altering certain genes involved in immune rejection, thereby increasing the chances that the human body will accept the transplanted organ.

Dr Rommel Ravanan, a consultant nephrologist and chief medical officer for NHS Blood and Transplant, said advances in genetics had played a major role in making such transplants increasingly feasible.

He explained that scientists can “knock out” some pig genes, reducing the ability of the human body to recognise the transplanted organ as being from a different species.

The latest achievement follows an earlier pig-kidney transplant performed at Massachusetts General Hospital in 2024. In that case, the recipient survived for 52 days after receiving the pig kidney before dying from heart complications that doctors said were unrelated to the transplant.

The 271-day survival recorded in Andrews’ case represents a substantial increase in the period a genetically edited pig kidney has successfully supported a living human without dialysis.

For patients suffering from end-stage kidney disease, the potential implications are significant. Dialysis can sustain life when the kidneys fail, but patients generally require regular treatment, while transplantation can provide greater freedom and, in suitable cases, improved quality of life.

However, doctors and researchers have stressed that xenotransplantation remains an experimental treatment. More studies and clinical trials will be required to establish the long-term safety, durability and effectiveness of genetically modified animal organs.

The latest case nevertheless provides important evidence that pig kidneys could eventually help patients remain off dialysis while waiting for human donor organs—and potentially, if future research confirms their safety and durability, become a long-term alternative for some patients.

Global Mirror News will continue to monitor developments in xenotransplantation and other emerging medical technologies aimed at addressing the worldwide shortage of transplant organs.