A 66-year-old man has set a new medical record after a genetically modified pig kidney functioned inside his body for 271 days, before doctors successfully transitioned him to a human donor kidney.
Tim Andrews received the pig kidney at Massachusetts General Hospital on January 25, 2025, after being diagnosed with end-stage kidney disease linked to type two diabetes.
Wilma gives Andrews a new lease on life
According to BBC News, the kidney came from a Yucatan miniature pig.
Biotechnology company eGenesis genetically modified it using CRISPR-Cas9 technology, making 69 separate genomic edits to remove genes that trigger rejection, add human DNA to help hide the organ from Andrews’s immune system, and disable retroviruses hidden in the pig’s own DNA.
The organ began filtering blood and balancing fluids almost immediately, and Andrews left the hospital within a week.
He went on to throw the first pitch at a Boston Red Sox game during his recovery, naming the donor pig Wilma.
The transplant wasn’t without complications. Doctors treated a rejection episode two weeks in by adjusting his medication, and later reduced his immunosuppressants after roughly six months due to an infection.
That led to vascular damage, and doctors ultimately removed the pig kidney in October 2025.
“Wilma and I had to give up the fight,” Andrews said.
He returned to dialysis for 82 days before receiving a deceased human donor kidney on January 13, 2026, which has shown no signs of rejection across 231 days of follow-up since.
Andrews had faced a nine percent chance of receiving a human kidney within five years before the pig transplant bought him crucial time.
“Hope is the biggest thing, the chance to be free from the machine and live your life,” he said.
Groundbreaking scientific developments have made headlines before too. Researchers in Austria previously discovered how to effectively reverse the flow of time for a single particle within a quantum system, a genuine breakthrough for the future of quantum computing.
