In January 2001, the United States Public Health Serviced published the Public Health Service (PHS) Guideline on Infectious Disease Issues in Xenotransplantation. The Guideline had been published in draft form for public comment in September 1996. It was a product of the Department of Health and Human Services Interagency Working Group on Xenotransplantation which was formed in 1996 to develop a unified departmental approach to xenotransplantation and to provide sound policy recommendations to the US Secretary of Health and Human Services and is composed of representatives from the Food and Drug Administration (FDA), National Institutes of Health (NIH), the Centres for Disease Control and Prevention (CDC), the Health Resource Services Administration (HRSA), and staff from the Office of the Assistant Secretary for Planning and Evaluation (OASPE). This document recommends application of established procedures for infectious disease control to xenotransplantation and is aimed at minimising the risks to the public of human disease due to known and new diseases arising from xenotransplantation. It suggests safety measures for the procurement, screening and use of xenotransplantation products as well as clinical care requirements for recipients. It recommends maintaining systematic health records and storage of designated biological specimens from both the source animal and the patient in the event of a public health investigation. The Guideline reiterates an FDA position that nonhuman primates, because of unaddressed safety concerns, should not be used as source animals for xenotransplantation at the current time.

The Department of Health and Human Services has also established the Secretary's Advisory Committee on Xenotransplantation (SACX). The role of this committee of independent advisors is to consider the full range of complex scientific, medical, social, and ethical issues and the public health concerns raised by xenotransplantation and make recommendations to the Secretary on policy and procedures. The SACX is administered through the National Institutes of Health. In addition, the Department of Health and Human Services is developing a National Xenotransplantation Database (NXD). The NXD, intended to function for surveillance purposes, is still in pilot form and is administered through the Food and Drug Administration.

The Food and Drug Administration is the sole agency responsible for regulating clinical xenotransplantation in the United States, and as such has published several guidance documents with recommendations for sponsors of xenotransplantation clinical trials. These documents can be found on the internet at http://www.fda.gov/cber/xap/xap.htm, and several are still in draft form. They are consistent with the PHS Guideline on Infectious Disease Issues in Xenotransplantation, and offer additional recommendations regarding product issues, good manufacturing practices, and blood donor deferral in xenotransplantation. All FDA documents, as well as the PHS Guideline on Infectious Disease issues in Xenotransplantation can be accessed through the FDA Xenotransplantation Action Plan website ( http://www.fda.gov/cber/xap/xap.htm).

In the United States limited clinical trials in xenotransplantation are now in progress under FDA regulation; these include the investigational use of extracorporeal hemoperfusion over isolated porcine hepatocytes for patients with fulminant liver failure, and the transplantation of foetal pig neuronal cells into patients with refractory Parkinson's disease and other neurological diseases.