A man survives nine months with a pig kidney until successfully receiving a human one
The organ had been genetically modified and the patient, 66 years old, was able to do without dialysis
BarcelonaNew milestone in the use of animal organs to improve human health. A 66-year-old man with kidney failure has survived for nine months with a genetically modified pig kidney while waiting for a human kidney transplant, which was also successfully performed. The case is detailed in a study published in The Lancet and represents a new survival time record for an animal organ transplanted into a person.
The man, who was treated at Mass General Brigham in Boston, USA, suffered from kidney failure caused by type 2 diabetes. It is estimated that he only had a 9% chance of receiving a human kidney within five years and, additionally, he had a 40% risk of dying or being removed from the waiting list. For this reason, it was decided to try to gain time by transplanting the organ of a miniature Yucatán pig. The kidney in question was genetically modified to be compatible with his immune system and was transplanted in January 2025.
Although there was an early episode of rejection, the pig kidney functioned immediately and no transmission of porcine pathogens to the patient was detected. Afterwards, the man was able to go 271 days without the need for dialysis. After about six months, lesions began to develop in the blood vessels of the transplanted kidney. Over the weeks, these lesions eventually caused organ failure, for which the pig kidney was removed from the patient. Even so, the man did not produce any detectable antibodies against the pig kidney, which suggests a different mechanism from that usually observed in organ transplant rejection.
After the removal, the patient returned to dialysis for a few months until, at the beginning of 2026, a kidney from a deceased human donor was found that matched the characteristics the man required.
A single person
Despite the success of the operation, the authors of the study warn that this case is that of a single person without a comparison group and that the result reflects a careful selection of patients and intensive specialized care that may not be available in other hospital centers or countries.
Even so, according to Mass General Brigham, the results of the study highlight both the potential and the aspects that need to be improved in xenotransplants—the transplantation of animal tissues—as a bridge solution for patients on the waiting list for human kidneys. "We know that the best therapeutic option for patients with end-stage renal disease who have developed kidney failure is transplantation, but we simply do not have enough human organs to perform transplants in time," laments Leonardo Riella, of Mass General Brigham. The researcher argues that, for this reason, this procedure could help resolve this shortage of organs, first as a bridge to avoid having to use dialysis while waiting for the transplant, and in the future as a potential definitive therapy.