Health·ScienceAmerican man who volunteered for an experimental pig kidney transplant is off dialysis and wants to ‘give some people some hope’By Lauran NeergaardBy The Associated PressBy Lauran NeergaardBy The Associated Press In this photo vided by Mass General Brigham, from left, surgeons Dr.
Nahel Elias, Dr. Alban Longchamp, Dr. Tatsuo Kawai and Dr. Shoko Kimura transplant a genetically edited pig kidney into Bill Stewart June 14, 2025 at Massachusetts General Hospital in Boston.
Sarah Evans/Mass General Brigham via APA self-described science nerd is the American to get an experimental pig kidney transplant, at a crucial point in the quest to ve if animals organs really might human s.
The 54-year-old New Hampshire man is faring well after his June 14 operation, doctors at Massachusetts General Hospital announced Monday.
“I really wanted to contribute to the science of it,” Bill Stewart, an athletic trainer from Dover, New Hampshire, told The Associated Press.
That’s not the only milestone the Mass General team is marking: A pig kidney has kept another New Hampshire man, Tim Andrews, off dialysis for a record seven months and counting.
Until now, the longest that a gene-edited pig organ transplant was known to last was 130 days.
Based on lessons from the New Hampshire men and a handful of other one-off attempts, the Food and Drug Administration apved pig ducer eGenesis to begin a rigorous study of kidney xenotransplants.
“Right now we have a bottleneck” in finding enough human organs, said Mass General kidney specialist Dr. Leonardo Riella, who will help lead the new clinical trial.
More than 100,000 people are on the U.S. transplant list, most who need a kidney, and thousands die waiting.
As an alternative, scientists are genetically altering pigs so their organs are more human, less ly to be immediately attacked and destroyed by people’s immune system.
Initial experiments, two hearts and two kidneys, were short-d and included very ill patients. Chinese reers also recently announced a kidney xenotransplant but released little information.
Then an Alabama woman whose pig kidney lasted 130 days before rejection mpted its removal, sending her back to dialysis, helped reers shift to not-as-sick patients.
‘Give some people some hope’ In New Hampshire, high blood pressure caused Stewart’s kidneys to fail but he had no other health blems.
It can take up to seven years for people with his blood type to find a matching kidney from a deceased donor, and some would-be living donors didn’t qualify.
After two years in dialysis, he heard Mass General’s most recent xenotransplant recipient – Andrews – and applied to be the next candidate.
“I’ve always been a little bit of a science nerd,” Stewart said.
Conscious of how new these experiments are, he sought out Andrews for advice and ultimately decided, “worst case scenario, they can always take it out.” Thrilled to no longer have his time and energy sapped by dialysis, Stewart said he’s easing back into desk duties at work and visited his old dialysis clinic to “let everyone know I’m doing all right and maybe kind of give some people some hope.” Riella, the kidney specialist, said Stewart had his anti-rejection drugs adjusted to counter an early concern and that Andrews has needed similar adjustments.
He said it’s far too early to predict how long pig kidneys might be able to last — but it would be useful even if initially they can buy people time off dialysis until they get a matching human organ.
“A year, hopefully longer than that – that’s already a huge advantage,” he said.
The new eGenesis trial will vide gene-edited pig kidney transplants to 30 people age 50 or older who are on dialysis and the transplant list.
Another developer of gene-edited pig organs, United Therapeutics, is to start enrolling people in a similar FDA-apved study. Fortune Global Forum returns Oct. 26–27, 2025 in Riyadh.
CEOs and global leaders will gather for a dynamic, invitation-only event shaping the future of . Apply for an invitation.