Pig kidney keeps man dialysis-free for record 9 months
What's the story
In a groundbreaking medical achievement, a genetically modified kidney from a pig has kept a 66-year-old man alive for nine months. The patient, Tim Andrews, suffered from end-stage kidney disease due to type 2 diabetes and had only a 9% chance of receiving a human kidney within five years. The transplant was done at Mass General Brigham in Massachusetts and the details were published in the Lancet medical journal.
Transplant details
Surgeons transplanted genetically-modified kidney from a pig
Surgeons in the US transplanted a genetically-modified kidney from Wilma, a Yucatan miniature pig, into Andrews.
The organ was modified to be compatible with his immune system and kept him off dialysis for nine months. This is the longest period ever recorded for such a case.
It also marks the first time that pig's kidney has been used as a temporary "bridge" to human transplant.
Patient perspective
'I was alive'
Describing the pig kidney transplant as a "miracle," Andrews said, "I was alive, and I hadn't been in a long time."
He was able to perform daily activities such as cooking and taking long walks with his dog.
Before this breakthrough, no previous studies had documented xenograft survival beyond two months.
Modification process
Wilma the pig had 69 edits made to her genome
Before the transplant in January 2025, Wilma the pig had 69 edits made to her genome.
Some were designed to dodge viruses that could infect humans, while others made the organ more compatible with humans, reducing immune rejection chances.
The team behind this transplant said Andrews lived successfully with the genetically edited kidney for 271 days before receiving a human kidney from a donor.
Future prospects
Pig kidney transplants could help address organ shortage crisis
Dr. Leonardo Riella from the Center for Transplantation Sciences at Mass General Brigham said pig kidney transplants could help address the organ shortage crisis.
"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."
Organ failure
Further clinical trials will be needed to confirm these results
After about six months, the blood vessels in the pig kidney were damaged, leading to organ failure.
The team stressed that this was a single patient with no comparison group and the outcome reflected careful patient selection and intensive specialist care that may not be available elsewhere.
Further clinical trials like Andrews' will be needed to confirm these results, but they open doors for pig kidney transplants as a bridge for other people facing long waits for human kidneys.