For decades, the promise of xenotransplantation — the transplantation of organs from animals into humans — has remained just beyond reach. The field has long been dogged by immunological rejection, concerns over viral transmission and ethical dilemmas1. But in February 2025, a pivotal moment was reached when the US Food and Drug Administration approved the first clinical trial testing whether kidneys from genetically modified pigs could be safely transplanted into humans. Until then, xenotransplantation had been limited to individual cases approved under compassionate use or expanded access protocols. This pathway allows patients with serious, life-threatening illnesses to access experimental treatments when no other comparable options are available. A first-in-human clinical trial could lay the foundation for xenotransplantation to become a routine medical treatment, potentially saving thousands of lives each year.

doi: https://doi.org/10.1038/d41591-025-00020-0