Health
Genetically modified pig kidney functions for 271 days as a bridge to human transplant
A US patient with end-stage kidney failure survived nine months on a gene-edited pig kidney before receiving a human donor organ, according to findings in The Lancet.
The short version
- A genetically modified pig kidney functioned inside US patient Tim Andrews for 271 days, keeping him off dialysis until the organ failed and was replaced by a human donor kidney.
- The xenotransplant at Mass General Brigham represents the first documented case of a pig kidney serving as a successful bridge to a human organ transplant.
- Biotech firm eGenesis reported that a subsequent recipient has surpassed Andrews' duration, reaching 285 days of kidney function as of September 2026.
- Researchers plan to launch a formal clinical trial of up to 33 patients in 2027 to evaluate the safety and broader viability of pig kidney transplants.
Key facts
- Tim Andrews, a 66-year-old with end-stage kidney disease, received a kidney from a Yucatan miniature pig engineered with 69 genomic edits on January 25, 2025.[BBC News · The Guardian]
- The pig kidney functioned for 271 days without requiring dialysis before blood vessel damage and thrombotic microangiopathy caused it to fail in October 2025.[BBC News · Wired]
- Following 82 days back on dialysis, Andrews received a transplant from a deceased human donor in January 2026, which showed no adverse cross-reactivity from the prior pig organ.[BBC News · The Guardian]
- A female patient who received an eGenesis pig kidney in November reached 285 days of dialysis-free organ function by early September 2026.[Wired]
- The FDA has authorized eGenesis to run a formal clinical trial in up to 33 kidney failure patients aged 50 to 70 starting in 2027.[Wired]
What remains uncertain
- The precise immunological trigger for the blood vessel damage and inflammation that ended the pig kidney's function in Andrews remains unclear, as no anti-pig antibodies were detected.[BBC News · The Guardian]
- The surgical team noted the results are from a single-patient case with intensive specialist care and no control group, leaving generalizability across broader patient populations unproven.[The Guardian]