Pig kidney transplant success leads to new clinical trial at Massachusetts General Hospital
A self-described science nerd is the latest American to get an experimental pig kidney transplant, at a crucial point in the quest to prove if animal organs really might save human lives.
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. "I've always been a little bit of a science nerd."
Another patient off dialysis 7 months
That's not the only milestone the Mass General team is marking: A pig kidney has kept another man, Tim Andrews, of Concord, New Hampshire, off dialysis for a record seven months and counting. Andrews had his transplant back in January and was up and walking a week after the surgery.
"You can see the light at the end of the tunnel, all of a sudden, I am not in the darkness," Andrews said in a video after his surgery. "It's going to be the option for people that don't want to be on dialysis, they want to be able to be with their kids and loved ones."
Until Andrews, the longest gene-edited pig organ transplant lasted 130 days.
Stewart had no other health problems until high blood pressure caused his kidneys to fail. 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 spending five hours a day, three times a week for two years in dialysis, he heard about Mass General's most recent xenotransplant recipient – Andrews – and applied to be the next candidate.
"Fairly easy decision"
"I've always been a little bit of a science nerd," Stewart said in a video produced by the hospital. "For me, it was a fairly easy decision at this point in time in my life to try to give this a go and see what happens."
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." Stewart said that he was up and walking around the transplant unit a day or so after his surgery and was discharged from the hospital on June 21.
Now, as his recovery reaches three months, he's 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."
"I've always given my life to try to help other people, and for this is, if it helps in any small way, it will be worth it for me for sure," Stewart said.
Mass General kidney specialist Dr. Leonardo Riella 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.
FDA approves pig kidney transplant trials
Based on lessons from the New Hampshire men and a handful of other one-off attempts, the Food and Drug Administration approved pig producer eGenesis to begin a rigorous study of kidney xenotransplants.
"Right now we have a bottleneck" in finding enough human organs, said Riella, who will help lead the new clinical trial.
More than 100,000 people are on the U.S. transplant list, most of whom need a kidney, and thousands die waiting. As an alternative, scientists are genetically altering pigs so their organs are more human-like, less likely to be immediately attacked and destroyed by people's immune systems.
Initial experiments, two hearts and two kidneys, were short-lived and included very ill patients. Chinese researchers also recently announced a kidney xenotransplant but released little information. Alabama resident Towana Looney had a pig kidney transplant that lasted 130 days before rejection prompted its removal, sending her back to dialysis, which helped researchers shift to patients who are not as sick.
The new eGenesis trial will provide 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 about to start enrolling people in a similar FDA-approved study.
Mass General said that it had also been approved to proceed with a larger FDA-approved clinical trial.
First pig kidney transplant
A 62-year-old Weymouth man was the first person in the world to receive a pig kidney transplant. Rick Slayman had the groundbreaking surgery at Mass General in March of 2024, using a pig kidney from eGenesis in Cambridge that was genetically altered.
Slayman died two months later, but doctors at Mass General said that there was no indication it was from the transplant.
"Mr. Slayman will forever be seen as a beacon of hope to countless transplant patients worldwide and we are deeply grateful for his trust and willingness to advance the field of xenotransplantation," the hospital said in a statement.
Slayman said that receiving the transplant was one of the happiest moments of his life.