Pig kidney functions in U.S. man for record 271 days

A pig kidney functioned inside U.S. patient Tim Andrews for 271 days, the longest period ever recorded by U.S. doctors, before it stopped working and was removed.

Doctors transplanted the kidney in January 2025, when Andrews was 66. He told the BBC that the procedure gave him hope and spared him months of hospital visits for dialysis, which cleans the blood when the kidneys fail. After the pig kidney was removed in October, Andrews returned to dialysis for 82 days. He then received a kidney from a human donor in January 2026.

His treatment team at Mass General Brigham in Massachusetts said the case showed that pig organs could serve as a temporary solution while patients wait for a human donor organ. The work comes as doctors and researchers explore xenotransplantation because the supply of human transplant organs remains limited.

About 100,000 people in the United States are waiting for a kidney transplant, while roughly 25,000 kidney transplants are performed each year, the BBC reported. Andrews had been told that reaching the top of the waiting list could take as long as seven years. He had end-stage kidney disease linked to type 2 diabetes, and his kidneys were failing.

Researchers consider pigs promising for xenotransplantation because their organs are broadly compatible in size with human bodies and pigs have a long history of managed breeding. An ordinary pig kidney would trigger a powerful immune response in a human recipient. Scientists therefore developed Yucatán miniature pigs with 69 genetic changes, removing features that the human immune system recognizes and attacks, while adding human DNA intended to help protect the tissue.

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The transplant gave me hope and saved me from months of hospital visits where my blood would have had to be cleaned with dialysis machines.