Tim Andrews, a New Hampshire resident, made medical history by living for a record 271 days with a genetically modified pig kidney before its removal due to declining function. His pioneering journey, while concluding with a return to dialysis, provides invaluable insights into xenotransplantation, offering a beacon of hope for thousands awaiting organ transplants worldwide.
In a medical journey closely watched by the world, Tim Andrews, a 67-year-old man from New Hampshire, has etched his name in history. He lived for an unprecedented 271 days with a genetically modified pig kidney, setting a new world record for the longest duration a human has lived with a xenotransplanted organ. On October 23, 2025, surgeons at Massachusetts General Hospital (Mass General Brigham) removed the pioneering organ as its function began to decline, marking the end of a remarkable nine-month period that offered a glimpse into the future of organ transplantation.
Andrews’ experience, though culminating in a return to dialysis, is hailed as a monumental step forward in the quest for animal-to-human transplants, known as xenotransplantation. His courage and dedication have provided researchers with critical data, accelerating efforts to address the severe global organ shortage.
The Pioneer’s Unwavering Spirit and Personal Triumph
Diagnosed with end-stage kidney disease and suffering from diabetes since the 1990s, Andrews faced the exhausting reality of dialysis for six hours, three days a week. Recognizing his particularly hard-to-match blood type, he sought an alternative, bravely enrolling in Mass General’s xenotransplant pilot study. Upon receiving the organ on January 25, Andrews expressed profound hope, stating, “I believe this is the start of something that’s going to be fantastic. It’s going to be the option for people that don’t want to be on dialysis, they want to be able to be with their kids and loved ones.”
For nearly nine months, the pig kidney, affectionately dubbed “Wilma” by Andrews, profoundly transformed his life. He felt “re-energized and revitalized,” describing the transplant as “a miracle.” During this time, he regained a sense of normalcy and independence, able to enjoy simple pleasures like cooking, vacuuming, and long walks with his dog, Cupcake. A highlight of his renewed vitality came in June, when he had the honor of throwing out the first pitch at Fenway Park for his beloved Boston Red Sox.
In a statement, his transplant team lauded Andrews as “a selfless medical pioneer and an inspiration to patients with kidney failure around the world.” Andrews himself reflected on the journey, acknowledging it as “a punishing journey filled with unknowns and surprises” and expressing gratitude for “everything we discovered, learned and experienced.” He especially thanked Wilma, calling her “my hero” and emphasizing her role in this medical breakthrough.
The Science of Xenotransplantation: Overcoming Barriers
The success of Andrews’ transplant hinges on advanced gene-editing techniques applied to the pig organ. These modifications are crucial for making the animal organ more human-like, thereby reducing the risk of immune rejection, a primary challenge in xenotransplantation. While previous attempts at using unmodified animal organs often resulted in rapid failure, gene-editing has ushered in a new era of possibility.
Researchers have learned vital lessons from each experiment. Early pig organ transplants, including two hearts and two kidneys, were short-lived. However, focusing on patients with less severe illnesses for these experimental procedures has shown improved outcomes. The record Andrews surpassed was held by an Alabama woman whose pig kidney functioned for 130 days.
A Look Back: Key Milestones in Living Pig Organ Transplants
Tim Andrews is the fourth living patient in the United States to receive a pig kidney transplant. His journey builds upon the experiences of other pioneers:
- Richard Slayman: In March 2024, he became the first patient to receive a pig kidney at Mass General. He lived for two months post-transplant, with his death later attributed to health reasons unrelated to the xenotransplant, according to CNN reporting.
- Lisa Pisano: Received a pig kidney and a mechanical heart pump in April 2024. The pig organ was removed the following month due to limited blood flow, and she passed away in July 2024.
- Towana Looney: A 53-year-old, she received a gene-edited pig kidney at NYU in November 2024. The organ functioned for four months and nine days before being removed in April 2025 due to immune system rejection.
These cases, despite varying outcomes, collectively provide invaluable data, refining surgical techniques, immunosuppression protocols, and genetic modifications necessary for long-term success.
Addressing the Critical Organ Shortage
Andrews’ story underscores the urgent need for alternative solutions to the organ transplant crisis. More than 100,000 people are currently on the U.S. transplant waiting list, with the vast majority requiring a kidney, according to the National Kidney Foundation. Tragically, thousands die each year waiting for a suitable donor. Organizations like the United Network for Organ Sharing (UNOS) highlight that dialysis, while life-saving, is a temporary measure, with nearly 90,000 people specifically awaiting a kidney transplant in the U.S.
Xenotransplantation offers a promising pathway to bridge this critical gap, potentially making organs readily available to those who need them most, without the agonizing wait for human donors. While the ethical considerations of using animal organs remain a topic of discussion, the potential to save countless lives drives ongoing research and innovation.
The Road Ahead: Future of Xenotransplantation
The medical community remains committed to advancing xenotransplantation. Mass General Brigham has announced plans for a third pig kidney transplant later this year, continuing their pilot study. Beyond these trials, two companies, Egenesis and United Therapeutics, are actively preparing for more rigorous clinical trials of pig kidney transplants, signaling a move towards broader application.
International efforts are also gaining momentum, with surgeons in China reporting pig kidney transplants and even a transplanted pig liver, albeit short-lived. Each such case, regardless of its duration, contributes vital knowledge that refines the understanding of organ rejection, immune response, and long-term viability.
A Legacy of Hope
Tim Andrews’ journey is more than just a medical record; it’s a testament to human resilience and the relentless pursuit of scientific progress. His willingness to participate in this experimental procedure has undoubtedly paved the way for future advancements, bringing the reality of xenotransplantation closer to becoming a standard treatment option. As he resumes dialysis and remains on the waiting list for a human kidney, his story stands as a powerful symbol of hope and a profound contribution to medical science.
