Organ transplants of the future: planning for innovations including xenotransplantation

The future clinical application of animal-to-human transplantation (xeno-transplantation) is of importance to society as a whole. Favourable preclin-ical data relevant to cell, tissue and solid organ xenotransplants have been obtained from many animal models utilizing genetic engineering and pro-tocols of pathogen-free husbandry. Findings have reached a tipping point, and xenotransplantation of solid organs is approaching clinical evaluation, the process of which now requires close deliberation. Such discussions include considering when there is sufficient evidence from preclinical ani-mal studies to start first-in-human xenotransplantation trials. The present article is based on evidence and opinions formulated by members of the European Society for Organ Transplantation who are involved in the Transplantation Learning Journey project. The article includes a brief over-view of preclinical concepts and biology of solid organ xenotransplanta-tion, discusses the selection of candidates for first-in-human studies and considers requirements for study design and conduct. In addition, the paper emphasizes the need for a regulatory framework for xenotransplanta-tion of solid organs and the essential requirement for input from public and patient stakeholders.