271 days is the record, then pig kidneys fail unpredictably

The longest a gene-edited pig kidney has functioned in a living human is 271 days (Tim Andrews, eGenesis kidney, January-October 2025), after which the kidney's function declined and it had to be surgically removed. Before Andrews, Towana Looney's pig kidney lasted 4 months 9 days before rejection, and Rick Slayman died 2 months after his transplant (though his kidney was still functioning and death was from an unrelated cardiac event). The critical problem is not just the short duration but the unpredictability: researchers do not understand why pig kidneys fail when they do. The rejection in Looney's case was linked to reduced immunosuppression, but Andrews' kidney declined without any clear triggering event. There is no biomarker or monitoring protocol that reliably predicts when a pig kidney will begin to fail, which means clinicians cannot intervene proactively. For xenotransplantation to become a real clinical therapy rather than an experimental bridge, pig organs need to last years, not months, and the gap between 271 days and the 10-20 year durability expected of human donor kidneys is enormous. The field cannot close this gap without understanding the mechanisms of chronic xenograft loss, which requires more long-term clinical data that does not yet exist.