World Health Organization resolution on xenotransplantation

International Human Xenotransplantation Inventory: A 10-y Follow-up

BACKGROUND

Following the recommendations by a panel of experts gathered by the World Health Organization in 2005, an inventory was established to collect practices of human xenotransplantation worldwide (www.humanxenotransplant.org). The website was activated in October 2006, in collaboration with the International Xenotransplantation Association, the University Hospital Geneva, and the World Health Organization. A first report on the collected xenotransplantation activities was published in 2010 in the journal Transplantation. In 2020, the website was redesigned, and its hosting and management were transferred to the Sichuan Provincial People's Hospital.

METHODS

We collected information from publications in scientific journals, presentations at international congresses, the internet, and declarations of International Xenotransplantation Association members on xenotransplantation procedures in humans performed over the past 10 y.

RESULTS

A total of 5 new applications of human xenotransplantation were identified, with pig as source animal in all applications. The procedures involved transplantation of islets of Langerhans, skin, cornea, and choroid plexus cells. The treatments were performed in China, United States, New Zealand, and Argentina. No major complications or deaths were reported.

CONCLUSIONS

Several clinical applications of cell or tissue xenotransplantation are ongoing around the world. Compared with the previous reported period (1995-2010, with 29 activities, mostly without governmental regulation), the recent number of clinical activities was reduced, and all were officially approved. This information should be used to inform healthcare officials, staff, and the public with the objective of encouraging good practices based on internationally harmonized guidelines driven by initiatives such as the Changsha Communiqué.

The International Xenotransplantation Association consensus statement on conditions for undertaking clinical trials of porcine islet products in type 1 diabetes-- executive summary

The International Xenotransplantation Association islet xenotransplantation consensus statement describes the conditions for undertaking clinical trials of porcine islet products in type 1 diabetes. Chapter 1 reviews the key ethical requirements and progress toward the definition of an international regulatory framework for clinical trials of xenotransplantation. Chapters 2 to 7 provide in depth and agreed-upon recommendations on source pigs, pig islet product manufacturing and release testing, preclinical efficacy and complication data required to justify a clinical trial, strategies to prevent transmission of porcine endogenous retrovirus, patient selection for clinical trials, and informed consent. It is planned to update this initial consensus statement in a year's time in light of progress in research, changes in the regulatory framework, and comments submitted after publication.

Xenotransplantation as a model of integrated, multidisciplinary research

Xenotransplantation was proposed a long time ago as a possible solution to the world-wide shortage of human organs. For years, researchers in this field have almost exclusively directed their efforts towards combating the immunological barrier that precluded long-term xenograft survival. Studies have been conducted in both small and large animal models and the most relevant results have been obtained in pre-clincal studies, specifically those utilising the pig-to-nonhuman primate combination. In this context, a better understanding of the immunological mechanisms underlying the rejection of a xenograft have allowed the identification of specific targets of intervention that have resulted in considerable improvements in survival of porcine organs or cells in nonhuman primates. However it has also become apparent that if xenotransplantation has to enter the clinical arena, a multidisciplinary approach will be needed to comprehensively tackle the different issues related to the use of a xenograft to cure human disease.In this regard, the safety, ethics and regulatory aspects of xenotransplantation are currently being aggressively addressed to enable the initiation of xenotransplantation with a favourable risk/benefit ratio.