Genetically modified pig kidney keeps man alive for record nine months — SkimNews
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- Tim Andrews, a 66-year-old man with end-stage kidney disease caused by type 2 diabetes, received a kidney from a genetically engineered Yucatan miniature pig named Wilma at Mass General Brigham in January 2025, after facing a 9% chance of receiving a human kidney within five years.
- The pig kidney kept Andrews free of dialysis for a record 271 days — the longest dialysis-free survival following pig kidney xenotransplantation in a living human — before blood vessel damage developed at around six months and the organ eventually failed.
- The surgical team then bridged Andrews to a human kidney from a deceased donor, marking the world's first transition from a pig kidney xenotransplant to a human transplant; no pig viruses were detected at any point and no new antibodies against human tissue developed, meaning the pig kidney did not complicate the subsequent human transplant.
- Wilma the pig had received 69 genomic edits before the transplant — some designed to remove retroviruses that could pose risks to humans, others to reduce the odds of immune rejection — making her kidney compatible with Andrews's immune system.
- Dr. Leonardo Riella of Mass General Brigham's Center for Transplantation Sciences called the organ shortage "the greatest crisis" in transplantation and framed xenotransplantation as both a bridge therapy and a potential destination therapy once long-term safety and durability are established.
- The previous milestone — the first pig kidney transplant into a living person in 2024 — ended after 52 days when the patient died of heart problems, and no prior studies had documented xenograft survival beyond two months, according to the Lancet.
- The research team cautioned this was a single patient with no comparison group and that the outcome reflected careful patient selection and intensive specialist care that may not be available elsewhere, with further clinical trials still needed.
Why it matters: For the more than 40% of end-stage kidney patients who die or are delisted while waiting for a human organ, xenotransplantation just cleared its longest hurdle: 271 days dialysis-free and a clean handoff to a human kidney. The bridge concept works; the destination therapy doesn't yet — Wilma's kidney failed from blood vessel damage at month six, so durability remains the open question.
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