Pig kidney records 271‑day breakthrough in US transplant

Sun Sep 06 2026 10:34:33 GMT+0000 (Coordinated Universal Time)

A genetically engineered pig kidney worked in a human for 271 days, sparing a survivor months of dialysis and offering a new hope amid transplant shortages.

In January 2025, 66‑year‑old Tim Andrews received a pig kidney that beat the previous record by functioning for 271 days. The organ, modified with 69 gene edits to make it more human‑friendly, acted as a bridge while he waited for a human donor. After removal in October, Andrews went briefly on dialysis before receiving a successful human kidney. This milestone shows promise but also highlights challenges—such as immune response and vascular damage—still facing xenotransplantation.

Pig kidney records 271‑day breakthrough in US transplant

In the early months of 2025, a 66‑year‑old man named Tim Andrews turned a lifelong dialysis routine into a “hope” story. He received a kidney from a genetically‑modified pig that stayed functional for an unprecedented 271 days – far longer than any previous pig‑kidney trial. The kidney began working right away, did the job of filtering blood, and kept him alive for nearly nine months before it failed.

This huge step was made possible by a team at Massachusetts General Brigham that tweaked the pig’s DNA dozens of times. They removed features that would trigger the human immune system and added human‑like proteins to act as camouflage, turning a farm animal into a test‑tube “bridge” organ.

After the pig kidney was removed in the fall of 2026, Andrews had to dialyse for 82 days until a human donor kidney finally arrived in January 2027 and has been working well ever since. The whole journey sparked excitement but also raised questions: why did the pig kidney start to get damaged after six months? Scientists say the exact cause is still unclear, but the case shows both promise and the need for further research.

With around 100,000 Americans waiting for a human kidney but only 25,000 transplants a year, xenotransplantation may become a lifesaving stopgap for patients who can’t wait that long. Dr. Leonardo Riella, part of the research team, said, “We’re working hard to bring hope and believe pig kidneys can help patients bypass dialysis and reach a transplant.”

For 66‑year‑old Tim Andrews, the pig kidney was “the light at the end of the tunnel.” Though it didn’t last forever, the record‑setting days he survived gave him months of freedom and a new chance at life.