Pig kidney kept patient alive 9 months before human transplant, Lancet study finds

A 67-year-old man with end-stage kidney disease lived without dialysis for 271 days after receiving a gene-edited pig kidney, then went on to receive a successful human kidney transplant — the first reported case of a patient transitioning from a xenotransplant to a human donor organ. The findings, published Thursday in The Lancet, mark a milestone for the field of xenotransplantation and its potential to address a chronic shortage of donor kidneys.wired+1

From Pig Kidney to Human Kidney

Tim Andrews received the pig kidney on January 25, 2025, at Massachusetts General Hospital after his native kidneys were removed. The organ was provided by eGenesis, a Cambridge, Massachusetts-based biotech company founded by Harvard geneticist George Church. Using CRISPR-Cas9, eGenesis edited 69 pig genes — removing three pig antigen genes that trigger hyperacute immune rejection, neutralizing porcine endogenous retroviruses, and inserting seven human genes to improve compatibility.biz.chosun+1

The pig kidney functioned immediately, though Andrews experienced a T-cell-mediated rejection episode on day 14 that was controlled with immunosuppressive therapy. After about six months, a bacterial infection forced doctors to reduce his immunosuppressants, leading to microvascular inflammation and thrombotic microangiopathy — tiny blood clots that ultimately caused the kidney to fail. The organ was removed, and 82 days later, Andrews received a human kidney from a deceased donor in January 2026. A 231-day follow-up found no evidence of immunological sensitization from the earlier pig kidney.news.sbs+1

A Growing Track Record

Andrews is not the only success. Since March 2024, five patients have received eGenesis pig kidneys at Massachusetts General Brigham, with three maintaining kidney function for more than eight months without dialysis. A second patient has also transitioned from a pig kidney to a human transplant. A fifth patient, a woman, has now surpassed Andrews' record, living with a functioning pig kidney for 285 days as of Thursday, according to Wired.biz.chosun+1

eGenesis CEO Mike Curtis said Andrews "suffered two heart attacks during dialysis and relied on a bed or wheelchair, but he was able to walk on his own within days after receiving the pig kidney." When the pig kidney was later removed, "he was in much better health than nine months earlier".biz.chosun

The Road Ahead

More than 95,000 people in the United States are waiting for a kidney, but fewer than 28,000 kidney transplants were performed in 2025. The FDA has approved a clinical trial for eGenesis to transplant its gene-edited pig kidneys into up to 33 kidney failure patients aged 50 to 70 who are on the transplant waiting list, though that trial is not expected to begin until 2027.wired+1

"Our goal is to utilize xenotransplantation using gene-edited pig kidneys as a bridge therapy to help patients waiting for human kidneys escape dialysis," said lead researcher Leonardo Riella, "and ultimately, once safety and persistence are confirmed over the long term, to use it as an independent treatment".news.sbs