On Oct. 27, 2025, a New Hampshire man resumed dialysis after living with a gene-edited pig kidney for a record 271 days, doctors said. His experience is helping researchers in their quest for animal-to-human transplants.

Tim Andrews, 67, had the organ removed on October 23 because its function was declining, according to Mass General Brigham. In a statement, his transplant team called Andrews “a selfless medical pioneer and an inspiration” to patients with kidney failure.

Andrews’ experience illustrates lessons researchers have learned with each experiment involving what’s called xenotransplantation. The first attempts using pig organs gene-edited to be more humanlike – two hearts and two kidneys – were short-lived.

Then researchers began considering patients not nearly as sick as prior recipients for these experiments — and an Alabama woman’s pig kidney lasted 130 days before it had to be removed last spring, the record Andrews surpassed.

In June, the Mass General team transplanted a pig kidney into another New Hampshire man who continues to fare well. The pilot study is set to conclude with a third pig kidney transplant later this year.

Two companies, eGenesis and United Therapeutics, are preparing to begin more rigorous clinical trials of pig kidney transplants.

Surgeons in China also are pursuing this new field, reporting a pig kidney transplant last spring and separately a transplanted pig liver that had to be removed after 38 days.