A 67-year-old New Hampshire man has become the first person to survive for an extended period after receiving a genetically modified pig kidney transplant, a procedure that scientists suggest could serve as a crucial bridge for patients awaiting human organ donations. Tim Andrews lived with the animal organ, which he nicknamed Wilma, for 271 days before it was removed due to signs of rejection.
Andrews underwent the xenotransplantation in January 2025 at Massachusetts General Hospital in Boston, after suffering from kidney failure for two years due to diabetes, which necessitated three days a week of dialysis. The procedure, which lasted three hours, involved removing his diseased kidneys and implanting the modified pig kidney. He was discharged with 51 medications to prevent his body from rejecting the organ.
Initially, Andrews reported feeling well, attributing it partly to steroid medication. However, over the following months, his condition gradually declined, marked by reduced urination and flu-like symptoms indicating organ failure. After 271 days, the pig kidney was surgically removed.
"For 271 days, we fought it and fought it and fought it," Andrews stated. "I knew probably a week before they're going to take it out, that she was done. She was done fighting."
Following the removal of the pig kidney, Andrews was once again placed on dialysis, joining the approximately 90,000 Americans on the waiting list for a human kidney transplant. He described the experience as a return to his previous debilitating state, with fatigue and illness impacting his ability to walk and function.
"I was like, here I am again," Andrews said. "I can't walk, I want to sleep all day, I'm sick all the time. [Dialysis] is tough on the body, tough on the mind."
In January 2026, nearly a year after his initial experimental surgery, Andrews received a call offering a compatible human kidney. The transplant was successful, and he was discharged within days. He has since reduced his anti-rejection medication to 20 from the initial 51 and is managing potential side effects like blood sugar spikes.
The results of Andrews' experience with the pig kidney were published in The Lancet by a team from Massachusetts General Hospital. The authors cautioned that this is an individual case and does not prove the treatment's universal efficacy, but acknowledged its potential as a bridge therapy. This marks a significant development following the case of Richard Slayman, who in 2024 received the first successful genetically modified pig kidney transplant, though he died two months later from an unrelated heart issue.
Xenotransplantation, the transplantation of organs between species, has a long history of attempts dating back to the early 20th century. Pigs have been identified as a suitable donor species since the 1990s due to their availability and physiological similarities to humans. To date, the procedure has been attempted approximately a dozen times.
Andrews has become an advocate for organ donation, urging others to consider becoming donors. He also expressed hope that xenotransplantation will become more commonplace, offering a viable option for those facing long waits for human organs. "In a few years, we could see this becoming a lot more commonplace and more and more people getting the organs they need," he said.