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A genetically modified pig kidney functioned in a 66-year-old patient for an unprecedented 271 days
This achievement set a new record for xenotransplantation, offering a potential temporary lifeline for patients awaiting human organ transplants.
The groundbreaking surgery took place on 25 January 2025 at Mass General Brigham Hospital, according to the BBC.
The recipient, Tim Andrews, suffered from end-stage kidney disease caused by type 2 diabetes. Faced with a staggering seven-year waiting list and the grim reality that dialysis patients survive an average of only five years, he opted for the experimental procedure.
"I had a little bit of a shortage of time… it becomes very depressing," Andrews said. He described the pig organ as a beacon of hope. "Hope is the biggest thing, the chance to be free from the [dialysis] machine and live your life," he added.
The donor kidney came from a Yucatan miniature pig engineered with 69 genomic modifications. These tweaks humanised the organ, stripping away features that trigger immune attacks while disabling latent viruses hidden in the pig's DNA. Without these crucial edits, the human body would destroy the foreign tissue in minutes.
While doctors successfully managed early signs of rejection by adjusting Andrews' medication, the transplanted kidney eventually failed
Around six months after the surgery, the kidney's blood vessels sustained damage, leading to inflammation and eventually causing the organ to fail in October.
After the pig kidney was removed, Andrews spent 82 days back on dialysis before finally receiving a human donor kidney in January. This new organ is currently functioning well.
The procedure highlights xenotransplantation as a crucial bridge during severe organ shortages
Dr Leonardo Riella from the Centre for Transplantation Sciences at Mass General Brigham explained the urgency. Pointing to the 100,000 people awaiting kidneys in the US, he said, "We are in a crisis".
"We are working really hard to bring hope and we truly feel that xenotransplantation can be an alternative for patients who don't have a living donor where we could potentially bypass dialysis and get them to a transplant," Riella added.
A recent report in The Lancet detailed the findings. The authors concluded, "This case illustrates both the promise and the remaining challenges of clinical kidney xenotransplantation."
