Ethical issues with xenotransplantation clinical trials

Xenotransplantation is the transplantation of living cells, tissues or organs from one species to another, such as from animals to humans. This includes transplanting human material that has been exposed to animal material while outside the human body.

Some animal materials are already used in humans, such as pig heart valves, but these are treated so that they contain no living cells. In contrast, xenotransplants comprise living cells that perform the same functions as the organ, tissue or cells they are intended to replace.

Progress in international research has raised interest in investigating xenotransplantation as an alternative to the clinical use of human material.

While whole organ xenotransplantation remains a distant possibility until research overcomes immunological hurdles, there has been much progress in cellular xenotransplantation. The immunological, microbiological and physiological barriers to xenotransplantation are being investigated in pre-clinical and clinical trials internationally. Ultimately, these could be tested in Australian clinical trials.

Australia has a robust framework for the conduct of clinical trials, yet there is limited guidance on the ethical review and conduct of xenotransplantation trials.

Such trials pose unique challenges due to the potential for transmitting infectious and untreatable diseases from animals to humans. This poses a risk not only to research participants, but also to people with whom they come into contact.

Researchers conducting xenotransplantation may need to consider lifelong monitoring and to provide information about the trial to close contacts.

To address these issues, the Australian Health Ethics Committee of the National Health and Medical Research Council has drafted a chapter on xenotransplantation for inclusion in the National Statement on Ethical Conduct in Human Research. This chapter outlines institutional and researcher responsibilities, and highlights ethical considerations associated with xenotransplantation.

The draft chapter will soon be released for public consultation. For more information, visit http://www.nhmrc.gov.au/health-ethics/ethical-issues/animal-human-transplantation-research-xenotransplantation.