Cook Islands considering pig cell transplants banned in NZ

11.50 am

Health authorities are investigating plans for the Cook Islands to host maverick medical trials of xenotransplants -- banned in New Zealand -- of pig tissue into humans.

The Cook Islands government is expected this week to agree to host clinical trials by Auckland researchers who have claimed an international breakthrough in diabetes treatment after successfully transplanting pig cells into diabetic Mexican children.

But Health Minister Annette King said today she was surprised the Cook Islands looked set to enable the trials, and New Zealand health officials would be contacting the Cook Islands government immediately.

"We're not prepared to take the risk ... retroviruses can emerge in a number of years and affect whole populations," she told National Radio.

Auckland research company Diatranz has claimed the technique could eventually provide a cure for 15 million people worldwide with type one diabetes who need daily injections of insulin.

Six New Zealanders injected with pig islet cells in the mid-1990s are reported to still be alive and well as part of a continuing clinical trial, but Diatranz temporarily halted work on its early human trials after overseas fears that a pig virus might cross species to infect people.

Last July New Zealand's Health Ministry turned down a Diatranz application for new trials over fears of porcine retroviruses entering humans in pig tissue.

Diatranz presented a paper at a xenotransplantation congress in Chicago in September that said the pigs used in New Zealand trials were disease-free and incapable of transmitting retroviruses into humans.

But the then Director-General of Health Karen Poutasi said she had adopted "the precautionary principle, which requires that the ministry give the balance of doubt to protecting the community, should there be uncertainty about the evidence of risk or benefit".

In December the Government moved to implement these precautions by trying to push through Parliament stop-gap legislation to strengthen a de facto moratorium on xenotransplantation, the insertion of animal organs, such as pig hearts, or insulin-producing pancreas cells into humans.

The legislation was also supposed to give the Government some control over any future efforts to genetically engineer humans in New Zealand.

But the "precautionary approach" to the possibility of pig viruses crossing species into humans has triggered angry reaction from diabetes sufferers.

A constitutional lawyer, Mai Chen, has rejected as "unconstitutional" the proposed legal ban on transplanting animal cells into people, contained in amendments to the Hazardous Substances and New Organisms Act considered by Parliament's finance and expenditure committee.

Ms Chen said the ban would override an appeal she launched to the Medicines Review Committee on July 31 on behalf of Diatranz against the "unlawful" decision by the Ministry of Health. She said the appeal would be redundant if Parliament passed the proposed retrospective ban.

Environment Minister Marian Hobbs has previously warned the Government that implanting living animal cells in humans could shift retroviruses previously restricted to animal species into not only the transplant patient, but the rest of the human species. A retrovirus could cause infection in cells by duplicating its own genetic material and then inserting it into human DNA.

Human cells can be infected with viruses that exist in all pig cells, known as porcine endogenous retroviruses, and scientists fear they may cause disease in humans. Under the worst scenario, the viruses would mutate in people and cause epidemics.

According to Health Ministry safety and regulation chief adviser Bob Boyd the issue needs extensive public debate and scientific research.

"One doesn't know the risks to the community at large from this -- it might be useful for one individual, but what if you pass on a retrovirus?

"Then there's the cultural factor of your neighbour or the person who wants to court your daughter having animal cells inside them," Dr Boyd said.

"It's got to be debated publicly, and the full ethical guidelines, and the cultural, spiritual, and safety issues have to be considered."

But Diatranz medical director Professor Bob Elliott -- who has pioneered the transplant of pig tissue into human diabetics -- said recent research had indicated it was technically impossible for a retrovirus in pigs to be transferred to humans through cell transplants.

He said Diatranz agreed to stop its trials in NZ when the ministry first raised the possibility of a retrovirus crossing into humans in 1996.

"Six years later we can see this is a fantasy. Pig retroviruses can't exist in human serum because it is marked with a blood group that makes it immediately incompatible with human beings," he said.

It was not that porcine retroviruses couldn't cross from pigs to lower mammals, just that they could not cross to higher primates or to man, he said. He said he would not allow the trials in the Cook Islands to go ahead unless they could be done to strict scientific guidelines.

According to Labour MP Di Yates, who introduced a private member's bill three years ago to stop animal implants in humans, Canada had banned it and the United States allowed it only for people who were past childbearing age.

The potential for Cook Islands trials has raised the spectre of Milan Brych, who fled New Zealand to set up a cancer clinic in Rarotonga and treated up to 300 patients mainly from Australia.

Brych claimed to be a refugee from Communist Czechoslovakia and practised in New Zealand as a doctor during the 1970s. He said he had developed a cure for cancer based on what was believed to be apricot kernels.

When questions were raised by authorities about his qualifications he fled New Zealand for the Cook Islands, where then premier Albert Henry and health minister Joe Williams invited him, in 1977, to set up practice.

Brych took over the paediatric ward of the almost new Rarotonga Hospital and began treating people. Sixty patients are buried there in a cemetery known as the "Brych Yard".

- NZPA

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