Pig Kidney Keeps Patient Off Dialysis for 271 Days in Landmark Trial

Key points

• Tim Andrews received a pig kidney in January 2025 at Massachusetts General Hospital, avoiding dialysis for 271 days.
• The organ was genetically engineered with 69 modifications to prevent immune rejection and inactivate viruses.
• The pig kidney failed after nine months due to vascular damage, not immune rejection, and was removed.
• Andrews subsequently received a human donor kidney in January 2026, which is functioning well.
• eGenesis aims to expand trials to 33 patients across 10 US centers by early 2027, targeting market approval by 2029.

Background

Xenotransplantation has faced cycles of hope and disappointment since the 1980s. Previous attempts, including a 2022 pig heart transplant and a 2024 pig kidney transplant, resulted in patient deaths within months. Recent advances in genetic engineering and immunology have improved compatibility, shifting the focus from hearts to kidneys, which offer a safer fallback to dialysis if the transplant fails.

How outlets are covering it

The Financial Times and BBC emphasize the success of the 271-day duration as a proof of concept for bridging patients to human donors. New Scientist highlights the specific medical complication, noting that the organ failed due to vascular damage after an MRSA infection prompted a reduction in immunosuppression drugs, rather than immune rejection. While eGenesis views this as a step toward permanent replacement, experts like Michelle Willicombe caution that high costs and the need for further research mean pig kidneys will not compete with human transplants for at least 15 years.

Why it matters

With approximately 100,000 people waiting for kidney transplants in the US and 600,000 on dialysis, xenotransplantation offers a potential solution to the organ shortage. Successful long-term outcomes could reduce the physical toll of dialysis and save lives while waiting for human donors.

What to watch

eGenesis has received FDA approval for an expanded trial involving 33 patients across 10 US centers, set to begin early next year. The company also plans to collaborate with PorMedTec to start kidney xenografts in Japan in 2028. Two additional case reports, including one exceeding the 271-day record, are expected to be published this year.