A kidney transplanted from a genetically modified pig functioned inside a human patient for a record 271 days, according to medical teams and BBC reports. Tim Andrews, a 67-year-old patient with diabetes and end-stage kidney disease, received the experimental porcine kidney on January 25, 2025, as reported by KSL. The milestone achievement demonstrated the viability of xenotransplantation—using organs from other species—as a functional bridge for patients suffering from organ failure.
Record-Breaking Xenotransplant Functions for 271 Days
During the approximately nine months of graft function, Andrews experienced normal metabolic filtration and regained energy and quality of life, significantly reducing his need for dialysis during the functional period, according to findings detailed in Frontiersin. Andrews named his pig kidney Wilma and took 52 pills a day to help keep his immune system in agreement with the organ.
Advanced Genetic Modifications and Medical Management
Further gene editing involved deleting three glycan antigens, inserting seven human transgenes, and inactivating PERV strains A, B, and C. In total, 10 genes were edited to inhibit blood clotting and immunological rejection, including knocking out three xeno-antigens (GTKO/β4GalNT2/CMAH) and inserting seven human transgenes for immune regulation (CD46, CD55, EPCR, TBM, CD47, HO1, A20).
To prevent acute cellular rejection during the crucial first month, doctors utilized an induction regimen consisting of anti-thymocyte globulin and an anti-CD20 antibody, combined with maintenance therapy using an Fc silent anti-CD154 agent for costimulatory blocking. Although the patient maintained his dialysis regimen prior to the procedure, the xenograft successfully bridged the gap before ultimately showing signs of rejection, accompanied by two infections, which led to irreversible damage to the kidney’s filters.
Transition to a Human Donor Organ
After the pig organ eventually failed and was removed in October, Andrews returned to dialysis before a human donor was found, according to BBC. At nearly midnight on January 12, Mass General Brigham notified Andrews that a near-perfect match human kidney had been identified, leading to a successful three-hour transplant surgery the following morning at 8 a.m., as detailed by KSL.
Before proceeding with the human transplant, medical staff tested Andrews for new antibodies that could potentially react against the new human organ and found none.
Addressing the Global Organ Shortage
Xenotransplantation is being explored globally due to severe shortages of human organs for transplants. In the United States, roughly 100,000 people are waiting for an organ, with approximately 80% of them in need of kidneys, while only 25,000 transplants occur each year. More than 7,000 people in the UK are on the kidney transplant list. Patients often face long wait times, with dialysis compressing into a few hours every week the work a healthy body does continuously, taking a heavy physical and emotional toll.
| Metric / Event | Details |
|---|---|
| Patient Age & Condition | Tim Andrews, 67, diabetes and end-stage kidney disease |
| Pig Kidney Transplant Date | January 25, 2025 |
| Xenograft Duration | Record 271 days |
| Gene Edits in Donor Pig | 10 genes edited (3 xeno-antigens knocked out, 7 human transgenes inserted, PERV inactivated) |
| Human Kidney Transplant Date | January following the removal of the xenograft |
Reflecting on his journey as the first person in the world to transition from a pig kidney to a human kidney, Andrews expressed optimism for future medical advancements. I'm the first one that went across the bridge,
he said, according to KSL. This will do something for humanity.
Meanwhile, the Food and Drug Administration has authorized more extensive clinical trials that may include more than 30 patients across several transplant facilities.
