Genetically Modified Pig Kidney Bridges Nine Months for New Hampshire Patient Awaiting Human Transplant
In January 2025, Tim Andrews, a 68-year-old man from New Hampshire suffering from end-stage kidney disease, underwent a groundbreaking transplant at Massachusetts General Hospital. He received a pig kidney, genetically altered from a Yucatan miniature pig named Wilma, featuring 69 genetic modifications aimed at minimizing virus transmission and immune rejection. The procedure, conducted by surgeons Leonardo Riella and Tatsuo Kawai, enabled Andrews to forgo dialysis for 271 days. However, after contracting an MRSA infection, his immunosuppressive medication was decreased, resulting in organ failure. He subsequently returned to dialysis for three months before obtaining a human kidney in January 2026. This pioneering case, reported in the Lancet on September 3, represents the first instance of using a pig kidney as a transitional solution for human transplantation.
Key facts
- Tim Andrews, a 68-year-old New Hampshire resident, received a genetically modified pig kidney at Massachusetts General Hospital in January 2025.
- The pig kidney, from a Yucatan miniature pig named Wilma with 69 genetic edits, kept Andrews off dialysis for a record 271 days.
- Andrews developed an MRSA infection about six months post-transplant, leading to reduced immunosuppression and eventual kidney failure.
- After the pig kidney was removed, Andrews received a donated human kidney in January 2026.
- The case was published September 3 in the Lancet, marking the first successful bridge use of a pig kidney to human transplant.
- Leonardo Riella, lead author and medical director at Mass General Brigham, called the nine-month duration 'mind-blowing.'
- Since Andrews, five additional pig kidney transplants have been performed, with one patient surpassing Andrews' record.
- In the U.S., nearly 110,000 people are on the transplant waiting list, with over 95,000 awaiting a kidney and fewer than 28,000 receiving one in 2025.
Entities
Artists
- Tim Andrews
- Leonardo Riella
- Tatsuo Kawai
- Richard Slayman
- David Mulligan
- Mike Curtis
- Sarah Kuta
Institutions
- Massachusetts General Hospital
- Mass General Brigham
- Lancet
- NBC News
- NPR
- Guardian
- New Scientist
- STAT
- Yale School of Medicine
- eGenesis
- New York Times
- Smithsonian Magazine
Locations
- New Hampshire
- United States
- Boston
- Massachusetts
- Yucatan
- Longmont
- Colorado