Record 271-Day Pig Kidney Transplant Marks Milestone in US Xenotransplantation Trials

Key points

• Tim Andrews received a pig kidney on Jan. 25, 2025, and remained dialysis-free for 271 days before receiving a human kidney earlier this year.
• The pig kidney was genetically engineered to remove rejection-prone proteins and add human genes, with no signs of immune rejection during the 271-day period.
• The case was published in The Lancet and described as the longest dialysis-free survival following porcine kidney xenotransplantation in a living human.
• eGenesis and Mass General Brigham are expanding trials to 33 patients across 10 US centers, with a goal of marketing approval by 2029.
• The pig kidney served as a bridge to a human transplant, with no evidence that the xenotransplant hindered the success of the subsequent human kidney transplant.

Background

Xenotransplantation has faced cycles of hope and disappointment since the 1980s, but recent advances in genetic engineering and immunology have revived interest. In 2024, Mass General Brigham performed the world's first pig-to-human kidney transplant, which lasted 52 days. The current case builds on that milestone, demonstrating longer-term viability and the potential for animal organs to serve as a bridge to human transplants.

How outlets are covering it

NBC News emphasizes the record-breaking 271-day survival and the transition to a human kidney, highlighting the potential for xenotransplantation to address the organ shortage. The Financial Times provides broader context, noting that five patients at Mass General have undergone successful pig kidney transplants since March 2024, with three lasting over eight months. The FT also highlights the FDA's approval of an expanded trial and the collaboration with a Japanese partner, PorMedTec, for future trials. Both outlets agree on the significance of the case but differ in scope, with NBC focusing on the individual patient and the FT on the broader clinical and regulatory landscape.

Why it matters

The success of the 271-day pig kidney transplant demonstrates that xenotransplantation can safely sustain patients while they wait for human donors, potentially alleviating the organ shortage. The expansion of clinical trials and the goal of marketing approval by 2029 suggest that this technology could become a standard treatment option for end-stage kidney disease in the near future.

What to watch

The FDA has authorized an expanded clinical trial of eGenesis pig kidneys in 33 patients across 10 US centers, with plans to begin early next year. The company is also collaborating with PorMedTec to start kidney xenografts in Japan in 2028. The goal is to achieve marketing approval by the end of 2029, with the potential for xenotransplantation to become a destination therapy if long-term safety and durability are established.