Pig Kidney Transplant Sets Record: 271 Days Dialysis-Free Before Human Transplant

Record-Breaking Pig Kidney Xenotransplant: 271 Days Dialysis-Free, Then a Human Transplant

A genetically modified pig kidney has kept a patient with end-stage kidney disease alive and dialysis-free for a record 271 days — the longest survival with a porcine kidney in a living human — before successfully “bridging” him to a conventional human kidney transplant, in a world-first case published in The Lancet. The milestone, achieved by surgeons at Massachusetts General Hospital (Mass General Brigham) in Boston, marks a major step toward solving the global organ shortage and could eventually offer hope to the thousands of Australians and millions worldwide waiting for a donor kidney.

What happened: a world-first “bridge” transplant

Tim Andrews, a 68-year-old retired grocery store manager from Barrington, New Hampshire, received a kidney from a genetically engineered Yucatan miniature pig named Wilma on 25 January 2025. At the time, Andrews had end-stage kidney failure caused by type 2 diabetes. His outlook on the standard transplant waiting list was stark: just a 9% chance of receiving a human kidney within five years, against a greater than 40% risk of dying or being removed from the list.

According to the case report, published in The Lancet on 3 September 2026:

• The pig kidney supported his renal function for 271 days without any dialysis — the longest dialysis-free period ever recorded after a pig-to-human kidney transplant.
• It was the first time a pig organ has served as a temporary “bridge” to a subsequent human organ transplant.
• After roughly six months, damage developed in the kidney’s blood vessels, progressing to organ failure; the organ was removed at nine months.
• After several months back on dialysis, Andrews received a kidney from a deceased human donor in January 2026 — which was working well at six months of follow-up.

Why the pig kidney was not rejected

The key to the breakthrough lies in the genetic engineering of the donor pig. Before transplantation, Wilma’s genome had received 69 edits:

• Some edits were designed to inactivate porcine endogenous retroviruses and other pathogens that could theoretically pose a risk to humans.
• Other edits were made to improve compatibility with the human immune system, reducing the odds of hyperacute rejection.

Remarkably, the team reported that no new antibodies against human tissue were detected after the procedure, suggesting the pig kidney had not made a subsequent human transplant more difficult. No pig viruses or other pig pathogens were detected at any point during the 271 days.

Why this matters: the organ shortage crisis

Kidney transplantation offers the best survival and quality of life for people with end-stage kidney disease — but demand for human organs far outstrips supply in nearly every country.

• More than 100,000 people are on the US transplant waiting list, the vast majority awaiting a kidney.
• Australia faces a similar squeeze, with hundreds of patients on dialysis for years and some dying while waiting for a compatible donor kidney.
• Xenotransplantation — transplanting living organs from one species into another — has long been proposed as a scalable solution.

“The organ shortage is the greatest crisis we have right now in transplantation,” said study lead author Dr Leonardo Riella of the Center for Transplantation Sciences and the Division of Nephrology at Mass General Brigham. “Our vision is that xenotransplantation could help address this gap — initially as a bridge to get patients off dialysis while they wait for a human donor kidney, and potentially, as we establish long-term safety and durability, as a destination therapy in its own right.”

How this case compares with earlier attempts

The field has advanced rapidly in just a few years:

• 2024: Richard “Rick” Slayman became the first living person to receive a pig kidney, surviving 52 days before dying of cardiac causes unrelated to the transplant.
• 2025: Towana Looney lived with a pig kidney for 130 days before it was removed due to rejection — the previous record.
• 2026: Andrews’ 271-day survival, followed by a successful human transplant, now stands as the benchmark.

Andrews, who describes the procedure as a “miracle”, told reporters he could now be looking at “decades” of life, and was able to cook, vacuum and walk his dog, Cupcake, throughout his months with the pig kidney. He has since received a human donor kidney that he says is “running perfect”.

Cautions and next steps

The researchers stress that this is a single patient case with no comparison group, and that the outcome reflected careful patient selection and intensive specialist care that may not be available elsewhere. Further clinical trials are needed before pig kidney transplantation can be offered more widely — though experts involved in the field now talk about the therapy becoming viable within roughly five years, rather than the ten previously estimated.

Frequently asked questions

What is xenotransplantation?

Xenotransplantation is the transplantation of living cells, tissues or organs from one species into another — for example, transplanting a genetically engineered pig kidney into a human. It is being developed to help overcome the chronic shortage of human donor organs.

How long did the pig kidney last?

The kidney functioned for 271 days — about nine months — without the need for dialysis. It was removed after blood vessel damage progressed to organ failure, and the patient later received a human kidney.

Was the pig kidney a permanent replacement?

In this case it was used as a “bridge”: it kept the patient alive and off dialysis while he waited for, and ultimately received, a human donor kidney. The long-term vision is that pig organs might one day also serve as destination therapy.

Why are pig organs rejected by the human body?

Without modification, the human immune system recognises pig organs as foreign and attacks them, often within minutes or hours (hyperacute rejection). Genetic editing removes or alters the sugar molecules and proteins that trigger this response, and adds human compatibility factors.

Is a pig kidney transplant safe?

Safety evidence is still early. In this case, no pig viruses or pathogens were detected, and the pig kidney did not appear to create antibodies that would jeopardise a later human transplant. However, experts caution that much larger trials are needed to establish safety and durability.

What does this mean for Australian patients?

While clinical availability is still years away, the case strengthens the case for investment in xenotransplantation research and clinical trials, and reinforces the ongoing importance of organ donation for the thousands of Australians waiting for a kidney.

Sources: The Lancet (3 September 2026); Massachusetts General Brigham; NBC News; The Guardian.