Medical professionals in the United States have announced a major milestone in xenotransplantation, reporting that a genetically altered pig kidney successfully functioned inside a human patient for a record 271 days. The procedure, performed at Mass General Brigham, offers new encouragement for addressing severe global shortages of human organs.

The recipient, Tim Andrews, received the experimental implant in January 2025 at the age of 66 after developing end-stage kidney disease linked to type 2 diabetes. Faced with a potential seven-year wait for a human organ—while average life expectancy on dialysis remains significantly shorter—Andrews embraced the procedure as an essential lifeline.

Medical teams utilized an organ sourced from a Yucatan miniature pig that had undergone 69 precise genomic edits. These biological adjustments are designed to prevent the human body from instantly destroying foreign tissue, employing both the removal of incompatible pig cellular markers and the integration of human genetic traits to evade immune detection.

The modified organ began filtering waste from the bloodstream immediately after the surgical attachment. While clinicians managed early indications of immune rejection by modifying his medication regimen, the organ eventually developed vascular damage and inflammation after approximately six months, leading to its removal in October 2025.

Following the removal of the pig kidney, Andrews underwent a brief period of dialysis before successfully receiving a traditional human donor organ. Details of the milestone case have been documented in the medical journal The Lancet, providing critical insights for researchers exploring animal-to-human transplants.

Specialists note that the immense gap between supply and demand continues to fuel exploration into animal organs, with tens of thousands of patients currently waiting for renal transplants in the United States alone. Experts believe that successfully utilizing modified animal organs could eventually serve as a reliable temporary bridge, sparing patients from prolonged reliance on dialysis machines.

Reporting based on coverage first published by BBC News. Read the original report at BBC News.