BOSTON (VINnews) — A genetically edited pig kidney kept a New Hampshire man off dialysis for a record nine months before doctors removed the organ and later transplanted a human kidney into the same patient, researchers reported Thursday.
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Tim Andrews, then 66, received the pig kidney on Jan. 25, 2025, at Massachusetts General Hospital. The organ functioned for 271 days, the longest dialysis-free period recorded after a pig-to-human kidney transplant. When the kidney began to fail, surgeons removed it in October 2025. Andrews returned to dialysis for about three months and received a kidney from a deceased human donor in January 2026.
The case, published in The Lancet, is the first known instance in which a pig kidney was used as a temporary bridge until a human organ became available. Doctors said the later human transplant has functioned well and that the earlier pig kidney did not appear to make the second operation harder.
The donor pig was produced by Cambridge, Massachusetts-based eGenesis. Scientists used gene-editing tools to alter dozens of pig genes, aiming to reduce immune rejection and lower the risk of transmitting animal viruses. Andrews’ kidney came from a Yucatan miniature pig; he referred to the organ as “Wilma,” after the donor animal.
Andrews had end-stage kidney disease caused by type 2 diabetes and high blood pressure. He had been on dialysis for more than two years and faced long odds of receiving a matching human kidney because of his blood type. After the pig transplant, he was able to live without dialysis, regain strength and resume daily activities.
Researchers said early signs of immune attack were treated by adjusting medication. Over time, however, blood vessels in the pig kidney were damaged and the organ lost function. No pig viruses were detected in the patient, according to the research team.
Mass General Brigham transplant specialist Dr. Leonardo Riella said the organ shortage remains the central crisis in transplantation. Tens of thousands of people wait for kidneys each year, and many die or become too sick before a match is found. A functioning pig kidney, even for months, can spare patients the physical toll of dialysis and buy time on the waiting list.
Two patients who first received these gene-edited pig kidneys have now gone on to receive human donor organs. Researchers said the longer survival of the pig kidneys is providing data for larger clinical trials now getting under way.
Xenotransplantation — the use of animal organs in people — remains experimental. Earlier pig kidney recipients lived for shorter periods, and some patients died after the procedures. Scientists caution that pig organs are not yet a permanent replacement for human kidneys, but the Andrews case strengthens the argument that they can serve as a temporary lifeline.