To the editor:

We are writing on behalf of the Ethics Committee of the International Xenotransplantation Association (IXA). Our committee recently expressed concern about the need for international guidelines for overseeing clinical xenotransplantation. We have published letters in scientific journals and corresponded with representatives of the World Health Organization (WHO) regarding these concerns. Although clinical xenotransplantation provides a potentially promising solution to the shortage of human organs and tissues, the potential to introduce new infections from xenogeneic source animals into the human populace is a concern that mandates extreme caution. In view of this risk, considerable effort has gone into the development of guidelines and oversight procedures for husbandry of source animals and recipient monitoring in several countries. However, clinical xenotransplantation is also carried out in countries lacking such guidelines and oversight. Some of these transplants are commercial enterprises providing cosmetic and medical treatments, whereas others are clinical trials. Given that individuals may freely travel from one country to another to undergo such procedures, international cooperation is needed to develop universal oversight procedures and standards, including ethical and monitoring guidelines.

Last October, international health officials representing more than 20 member states, members of the transplantation community and WHO representatives met in Madrid to discuss policies on transplantation. This meeting resulted in a report by the WHO secretariat, which has recently been published online (http://www.who.int/gb/EB_WHA/PDF/ EB113/eeb11314.pdf). This document includes a draft resolution to be considered by the WHO's executive board in January 2004. The draft resolution recognizes both the potential benefit and the potential infectious risks associated with xenotransplantation. Most importantly, it urges the adoption of appropriate regulation and surveillance of xenotransplantation by national health authorities of member states, as well as the development of protective measures to prevent transmission of infections that may arise after xenotransplantation. Member states are further urged to support international collaboration on the prevention and surveillance of infections resulting from xenotransplantation. Our committee believes that adopting all of these measures would be of enormous value in minimizing the potential risks of xenotransplantation. The draft resolution further requests that the WHO's director-general support such international cooperation, create a global evidence base for evaluation of xenotransplantation practices, and provide technical assistance and expertise to support xenotransplantation efforts and oversight in member states.

The IXA's ethics committee is highly encouraged by the drafting of this resolution and strongly urges its adoption by the WHO's executive board. If this resolution is ultimately adopted by the fifty-seventh WHO assembly, it will be a major step toward minimizing infectious risks associated with xenotransplantation. Without organized international cooperation, the best efforts at minimizing these risks in countries with appropriate regulatory oversight may be thwarted by the free travel of individuals undergoing unmonitored xenotransplantation in countries lacking such regulation.