CRISPR-Edited Pig Kidney Sustains Patient 271 Days as Bridge to Human Transplant

A case report published in The Lancet (Sep 3, 2026) by Mass General Brigham researchers led by Dr. Leonardo Riella describes Tim Andrews, 66, who lived 271 days without dialysis on a CRISPR-Cas9-edited pig kidney (EGEN-2784, supplied by eGenesis) before receiving a human donor kidney in January 2026 — the longest dialysis-free survival yet reported for a xenotransplant recipient and the first documented transition from a pig organ to a human transplant. The kidney carried edits eliminating three glycan antigens (to prevent hyperacute rejection), seven inserted human transgenes (immune and coagulation regulation), and inactivation of porcine endogenous retroviruses. An early episode of T-cell-mediated rejection resolved with treatment, and no pig pathogen transmission was detected, supporting xenotransplantation's potential as a bridge therapy for the organ shortage.