U.S. regulatory bodies have adapted several sets of voluntary federal
guidelines to govern xenotransplantation technologies and their public health
implications. In addition, responsibility for ensuring that proper protocols
are followed often falls to local institutional review boards. Here's a
In these excerpts from their interviews with FRONTLINE, xenotransplantation
researchers and a medical ethicist discuss what will be asked of the individual
xenotransplant recipient, as well as the larger population, if pig-to-human
transplants moves forward.
These excerpts from FRONTLINE's interviews for "Organ Farm" address the costs
of financing xenotransplants, conflicts of interest in its development, unknown
risks to the population, and the need for more open public discussion.
In his FRONTLINE interview Dr. Walid Heneine, an expert on retroviruses at
the Centers for Disease Control, discusses the PERV virus threat. He argues
that limited human clinical trials should proceed, albeit with caution and
In this 1999 article in the Journal of Law, Medicine and Ethics,
professor Margaret A.Clark lays out her concerns about the clinical risks and
ethical and policy issues surrounding xenotransplants. She recommends a
moratorium be placed on any human trials with whole organs "until a track
record is established with xeno cellular transplants." This excerpt focuses on
the ethical and public policy questions she poses.
Here is part of medical ethicist Harold Y. Vanderpool's response to Margaret
A. Clark's critique of xenotransplantation. It was published in the same issue
of the Journal of Law, Medicine and Ethics and focuses on the ethical
issues raised by Clark.
In this 1996 article from Nature Medicine reprinted on the CDC's web
site, Jonathan Allan argues that public health agencies in the United States
have been reluctant to regulate xenotransplantation, despite the evidence of
cross-species virus threats (he focuses specifically on baboon-to-human
viruses). He writes, "In choosing voluntary guidelines to be enforced at a
local level, rather than federal regulations, the FDA/CDC committee has chosen
the least stringent and possibly least successful method of policing these
(Note: Pdf file requiring Acrobat 4.0.)
This article by A.S. Daar in the 1999 Bulletin of the World Health Organization
presents a more international perspective on xenotransplantation's policy and
social issues. It covers religious belief, biomedical ethics, community
consent, the restrictions imposed on patients and problems in allocating
resources to xenotransplantation.
(Note: Pdf file requiring Acfrobat 4.0)
retrovirus scientist Jonathan Allan, professor of surgery A.P.R. Aluwihare,
xeno researcher Fritz H. Bach, bioethicist Arthur Caplan, law professor
Bernard Dickens, infectious disease expert Jay A. Fishman, Netherlands
Scientific Secretary Eric van Rongen and xenotransplantation professors of
surgery C.G. Groth and M.E. Breimer.
(Note: Pdf file requiring Acrobat 4.0.)
This December 2000 report by the International Society for Heart and Lung
Transplantation advises that human clinical xenotransplantation trials are
still far in the future. It advises that clinical xenotransplantation trials
should not be undertaken until authorities have determined a minimal virus
risk, and until 60% of pig heart and lung organs survive in non-human primates
for a minimum of three months.
Many scientists agree that before allowing human clinical xenotransplant
trials, scientists must achieve survival rates of three to six months in
animals. In this 1996 article from the journal Emerging Infectious
Diseases, heart surgeon Robert Michler illustrates the history of the first
attempts at cardiac allotransplants (transplants from individuals of the same
species) in order to provide a comparison for the prospect of clinical
The focus of this 1998 paper in Nature Medicine is ethical issues raised
by the trade off of individual benefits from xenotransplants against societal
risk. Its authors are doctors and health policy experts. They propose a
temporary moratorium on new clinical xenotransplantation trials while a
national review is undertaken to examine uncertain public risks and develop
effective, responsible policy before new trials can proceed. At the time of
publication, over 200 participants in clinical trials already had been exposed
to cells, tissues or organs from other species. (Also, see FRONTLINE's
interview with Fritz H. Bach, one of the paper's authors.)
In January 2001, the FDA proposed a new rule which would greatly increase
information the agency makes public about the safety and progress in
experiments into gene therapy and xenotransplantation. The proposed rule
would require the FDA to release full descriptions of all clinical studies,
safety test records, copies of informed consent forms participants must sign,
procedures for monitoring, and updated records of safety problems on humans.
"Today's action is an important step in ensuring greater public confidence in
these revolutionary therapeutic technologies," said FDA
Commissioner Jane E. Henney. This proposed change came sixteen months after
Jesse Gelsinger, an Arizona teenager died in a gene therapy trial. It spawned
intense scrutiny of this experimental field and the FDA's regulation of
it. It also came several months after a lawsuit was filed against the FDA in November 2000 by the Campaign for Responsible Transplantation, a coalition of 90 public interest groups opposed to xenotransplantation. The group charges that the FDA had violated the Freedom of Information Act by witholding records of xeno clinical trials.
These transcripts of a January 1998 Department of Health and Human Services
workshop include discussion on the pilot study to implement a National
Xenotransplantation Registry Database (see the 1/22/98 transcript).