Liver Xenotransplantation: From Early Primate Trials to the First-in-Human Porcine Bridging Therapies

Liver transplantation remains the definitive treatment for end-stage liver disease and acute liver failure, yet a critical and persistent shortage of donor organs results in thousands of preventable deaths annually worldwide. Xenotransplantation has emerged as a potential solution to this structural deficit. This narrative review traces the evolution of liver xenotransplantation, from early non-human primate trials in the 1960s through the application of CRISPR/Cas9-driven multi-gene editing platforms in contemporary porcine donors. The immunological barriers that drove the transition from primate to porcine donors are examined, including hyperacute rejection mediated by anti-α-Gal antibodies, coagulation dysregulation and xenograft thrombotic microangiopathy. The genetic engineering strategies underlying current triple-knockout, ten-gene-edited donor pigs are reviewed alongside the preclinical non-human primate evidence establishing biological feasibility. The three pig-to-human liver xenotransplantation studies published between 2025 and 2026 are then analyzed, encompassing heterotopic auxiliary transplantation in a brain-dead decedent, extracorporeal liver cross-circulation and the first auxiliary liver xenotransplantation in a living recipient with a documented 171-day survival. These cases collectively provide preliminary evidence supporting proof-of-concept for porcine hepatic bridging therapy, with current evidence supporting a role for xenogeneic liver support as a temporary bridge to recovery or allotransplantation rather than definitive organ replacement. Xenograft thrombotic microangiopathy is identified as the principal remaining biological barrier, and the substantial translational challenges, including reproducibility, scalability and regulatory readiness that must be resolved before broader clinical application can be considered.