Xeno Advisory Committee Echoes Critics' Concerns
Lack of Clinical Success, Rogue Transplanters, and Infectious Disease Risks
(Washington, DC) - The fourth meeting of the Secretary's Advisory Committee on Xenotransplantation (SACX), which concluded yesterday, was remarkably devoid of public participants. Technical presentations by researchers and biotechnology companies that are transplanting live pig cells, tissues, and organs into baboons and humans dominated both days.
Many of the presenters substantiated concerns raised by the Campaign for Responsible Transplantation (CRT) - a coalition working to ban xenotransplants. These included: the ever-present risk of transferring pig viruses to humans, the difficulty of breeding transgenic pigs whose organs, cells and tissues would not be rejected by humans, the potential threat to the blood supply from the widespread adoption of xenotransplantation, and the lack of any clear clinical success in the field.
"The clinical viability of xenotransplantation was again estimated to be "about five years away" - a number that has been thrown around for the last 15 years, and which fuels continued spending on xeno research, despite limited resources and other pressing public health needs," says CRT Director Alix Fano.
Much of the meeting yesterday focused on controversial research being conducted by the New Zealand-based company Diatranz, Ltd., which transplanted pig islet cells into 12 diabetic children in Mexico and plans to perform other human experiments in the Cook Islands. The company's genetically modified pigs have tested positive for three classes of porcine endogenous retroviruses (PERVs). Though Diatranz claims that its patients have remained free of infection after one year - not long in the life of a retrovirus - one patient was found to have pig DNA circulating in his/her blood, suggesting a potential infection.
Diatranz's experiments were condemned by the New Zealand Ministry of Health, which enacted a moratorium on clinical xeno trials last year and issued a "xenotransplantation research warning" in a media release on March 7th. The release stated that: studies on the benefits to Diatranz's patients were inadequate and did not counterbalance the risks of transferring animal viruses to humans. Moreover, jurisdictions like Mexico and the Cook Islands did not have the appropriate regulatory mechanisms in place to safeguard public health or monitor patients and their contacts for viruses on a long term basis.
The SACX expressed concern that, by conducting research trials in countries with weak regulatory oversight, Diatranz and other rogue transplanters could jeopardize the health and safety of U.S. citizens.
"The fact is that xenotransplantation trials being conducted in the U.S. are just as dangerous as any conducted in Mexico because this technology is inherently dangerous and can never be made safe," says Fano. "Moreover, xenotransplant guidelines in the U.S. are voluntary and cannot be legally enforced. Patients can drop out of clinical trials and monitoring schemes at any time, and disappear - viruses and all. If we want to safeguard the public health, we should ban xenotransplantation now, and for good."