Pig Kidney Transplant Reaches Nine-Month Milestone
A woman has lived for more than nine months with a genetically edited pig kidney, marking the longest period that such an organ has functioned in a living human without dialysis.
Surgeons at Massachusetts General Hospital performed the transplant on November 22, 2025. By September 3, 2026, the kidney had functioned for 285 days, according to eGenesis, the Cambridge, Massachusetts, biotechnology company that developed the organ. The previous record was 271 days, achieved by Tim Andrews.
Researchers are studying pig organs as a response to the shortage of human donor kidneys. More than 95,000 people in the United States are waiting for a kidney, while fewer than 28,000 kidney transplants were performed in 2025. Patients wait three to five years and often require dialysis, a process that filters waste and excess fluid from the blood.
EGenesis used Crispr gene editing to remove pig genes associated with immune reactions, add human genes, and reduce the risk of transmitting pig viruses. Recipients must take immunosuppressive medication, as they would after a human organ transplant.
The woman is the fifth person to receive an eGenesis kidney through the Food and Drug Administration’s expanded access pathway, which permits experimental treatments for patients with conditions and limited alternatives.
Andrews received a pig kidney in January 2025. It was removed in October 2025 after declining function caused by small blood clots in the organ. He resumed dialysis and received a human kidney in January 2026. Another recipient also received a human kidney after eight months with a pig kidney.
EGenesis is using these cases to refine medication protocols. The FDA has authorized a trial of up to 33 patients, planned for 2027. Before then, the company expects to continue expanded-access transplants, with a one-year functioning kidney as its next target.