Pig kidney keeps New Hampshire man alive for record 271 days before human transplant

In a medical milestone, 66-year-old Tim Andrews lived for a record 271 days with a genetically modified pig kidney, marking the first successful use of a xenotransplant as a temporary "bridge" to a human organ. The kidney, which had 69 genetic edits to prevent rejection, kept Andrews off dialysis for nine months before failing due to blood vessel damage. After returning to dialysis, Andrews successfully received a human donor kidney in January 2026, offering new hope for addressing the critical global organ shortage.

Pig kidney xenotransplant record survival

• ▪A genetically modified pig kidney functioned inside 66-year-old Tim Andrews for a record 271 days, marking the longest documented survival of a pig kidney in a living human.
• ▪Tim Andrews of Concord, New Hampshire, received the experimental pig kidney transplant on January 25, 2025, at Massachusetts General Hospital.
• ▪The previous record for pig kidney survival in a living patient was held by Towana Looney, whose transplant lasted 130 days before removal in April 2025 due to rejection.

Genetically modified pig organ engineering

• ▪The transplanted kidney came from a Yucatan miniature pig named Wilma, whose genome was altered 69 times to reduce immune rejection and viral infection risks.
• ▪Genetic modifications to the pig's DNA aimed to make the organ less visible to the human immune system and eliminate potential viruses within the pig DNA.

Bridge to human kidney transplant

• ▪Following the removal of the pig kidney, Tim Andrews returned to dialysis for 82 days before receiving a successful transplant from a deceased human donor in January 2026.
• ▪The pig kidney transplant served as the first reported successful temporary "bridge" to keep a patient alive until a human donor kidney became available.
• ▪Six months of follow-up showed the human kidney functioned well and Tim Andrews developed no new antibodies against human tissue from the prior pig transplant.

Organ shortage transplant waiting lists

• ▪Approximately 100,000 people in the United States are waiting for a kidney transplant, while only about 25,000 such procedures are performed annually.
• ▪Tim Andrews, who suffered from kidney failure caused by type 2 diabetes, had only a 9% chance of receiving a human kidney within five years.

Patient dialysis-free survival outcome

• ▪After six months, blood vessels inside the pig kidney suffered progressive damage and inflammation, leading to gradual organ failure and its removal in October 2025.
• ▪The pig kidney allowed Tim Andrews to live dialysis-free for nine months, enabling him to resume daily activities like cooking, vacuuming, and walking his dog.

Debatable claims

• ▪Breeding genetically modified animals for human organ harvesting is ethically justified
• ▪Genetically modified animal organs should be used as temporary transplant bridges
• ▪Xenotransplantation is ready for widespread human clinical trials

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