Pig Kidney Functions for 9 Months Before Successful Human Kidney Transplant, a World First

A patient with end-stage kidney disease who received a pig kidney survived for 9 months without dialysis before successfully undergoing a human kidney transplant. The transition from a pig kidney to a human kidney transplant is the first of its kind worldwide.

According to the medical journal The Lancet on the 3rd (local time), researchers at Harvard Medical School and Massachusetts General Hospital published a case report on the treatment of 66-year-old Tim Andrews, who used a pig kidney as a “bridge” while waiting for a human kidney transplant.

Andrews developed end-stage kidney disease due to type 2 diabetes but had no suitable human kidney donor. He received a gene-edited pig kidney transplant on Jan. 25, 2025.

The kidney was provided by eGenesis, founded by George Church. Researchers edited 69 genes to prevent immune rejection and transmission of pig viruses to humans.

The transplanted pig kidney remained functional for 271 days, or approximately 9 months. The patient went without dialysis during this period, marking the longest dialysis-free period recorded among surviving patients. The previous record was less than 2 months.

Andrews received a human kidney from a donor who died in January 2026. The new kidney recovered function immediately, and follow-up monitoring showed no signs of immune rejection.

The pig kidney began functioning immediately after transplantation. Early T-cell-mediated rejection was controlled with treatment, and no transmission of pig pathogens was detected.

However, about 6 months after the transplant, a bacterial infection led to a reduction in immunosuppression, and the pig kidney developed microvascular injury and inflammation, gradually losing function. He received a human kidney transplant 82 days after the pig kidney was removed.

Leonardo Riella, the study’s corresponding author, said, “The shortage of organs is the greatest crisis facing transplantation,” adding that “xenotransplantation could initially serve as a bridge to help patients escape dialysis while waiting for a human kidney and, in the long term, could become an independent definitive treatment.”

The researchers said the case demonstrated both the potential of xenotransplantation and areas requiring improvement. The microvascular injury in the pig kidney provides important clues for developing future immunosuppression strategies, genetic editing of donor animals and monitoring techniques.

Massachusetts General Hospital performed the world’s first living-donor human kidney transplant in 1954. The researchers said, “The patients are the true pioneers in xenotransplantation,” adding, “Without their trust and courage, we could not have conducted this research.”