Pig kidney transplant helps US man avoid dialysis for nine months

A genetically modified pig kidney functioned inside a 66-year-old US man for 271 days, giving him nine months away from dialysis while he waited for a human transplant.

Tim Andrews received the kidney at Massachusetts General Hospital in January 2025 after developing end-stage kidney disease linked to type 2 diabetes. The pig organ began working immediately, but doctors removed it in October after its blood vessels began to suffer damage. The kidney became inflamed and eventually failed.

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I had a little bit of a shortage of time, it becomes very depressing.

Andrews spent another 82 days on dialysis before receiving a human donor kidney in January 2026. Doctors said the human kidney was working well. He described the chance to receive a pig kidney as a source of hope, particularly the possibility of living free from the dialysis machine.

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Hope is the biggest thing, the chance to be free from the dialysis machine and live your life.

The donor pig underwent extensive genetic modification to make its organs more compatible with humans. The changes aimed to reduce immune rejection and address infection risks associated with viruses in pig DNA. Doctors initially detected signs of rejection in Andrews, but successfully treated the reaction by adjusting his medication.

After about six months, however, the kidney’s blood vessels deteriorated. Doctors found no evidence that antibodies had attacked the organ, so the precise cause of its failure remains unclear. Researchers hope pig organs could eventually serve as temporary bridges for patients waiting for human donors. Dr Leonardo Riella said xenotransplantation could offer an alternative for patients without living donors, while acknowledging the field’s remaining challenges.

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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.