Pig kidney keeps two men alive long enough to receive human organs

Tim Andrews received a gene-edited pig kidney at Mass General Brigham on 25 January 2025. The organ worked for 271 days. Surgeons removed it in October 2025 when blood-vessel damage progressed. He went back on dialysis for 82 days. In January 2026 he received a human kidney from a deceased donor. That graft is working. He swims and rides a bicycle. The sequence, published in The Lancet in early September, is the first documented case of a pig kidney used as a bridge to a human transplant.

eGenesis, the Massachusetts firm that supplied the organ, says a second man followed the same path: a pig kidney first, then a human one, both now functioning. Five patients at Mass General Brigham have received eGenesis pig kidneys under a US Food and Drug Administration expanded-access route for people with no other option. Leonardo V. Riella, associate director of the Legorreta Center for Clinical Transplant Tolerance and lead author of the Lancet paper, said dialysis wears patients down until they are too sick to transplant or die on the list.

Andrews was 66 and in end-stage kidney disease from type 2 diabetes. His chance of a human kidney within five years sat at about 9 percent. The risk of dying or leaving the list sat above 40 percent. The donor animal was a Yucatan miniature pig named Wilma. The edits were designed to blunt hyperacute rejection and to inactivate porcine endogenous retroviruses. The kidney produced urine immediately. Doctors later cut his immunosuppression. Damage then appeared in the graft vessels. They explanted it at 271 days.

That span is the longest a pig kidney has functioned in a living person. A 1964 case, Edith Parker in Louisiana, lived 274 days with a chimpanzee kidney before she died. Andrews survived the explant, waited, and took a human organ. Mike Curtis, president and chief executive of eGenesis, told The New York Times the team sees no current downside to a pig kidney followed by a human one, a point they could not have claimed when the programme started.

Muhammad Mohiuddin of the University of Maryland, who was not on the paper, said the immediate clinical use is survival long enough to reach a human organ, even while laboratories still aim at a lasting xenograft. The US waiting list for kidneys is long. Dialysis keeps people alive at a cost to the heart, bones and daily hours. A bridge organ that lasts nine months changes the arithmetic for a subset of patients who can enter an FDA pathway and a centre that has the surgical and immunological bench.

The paper does not show that pig kidneys are ready as a permanent replacement. Andrews's graft failed. The second patient's details are thinner in the public summaries. Five expanded-access cases are not a trial with a control arm. Rejection biology, infection risk and the cost of the animals remain open. What the Lancet report does fix is a sequence that had not been written down before: pig kidney in, pig kidney out, human kidney in, patient alive and active.

Andrews has said he volunteered because he thought he was near the end and wanted the work to count for someone else. The human kidney he received this year is the result that matters to him. For transplant programmes the result that matters is the 271-day clock and the second successful hand-off. Those two data points will be cited in the next expanded-access applications and in any later trial protocol that treats a xenograft as a planned interval rather than a last throw.

Mass General Brigham and eGenesis will now be asked how many more patients they can run through the same sequence this year, what failure rate they will accept, and whether insurers will pay for an organ that is designed to come out. Those are operational questions. The clinical fact from the Lancet paper is already on the record. A pig kidney kept a man off dialysis for nine months. A human kidney then took over. He is alive.