Issues Magazine


By Bob Elliott

Bob Elliott argues that the current ban on xenotransplantation in Australia should be overturned.

Xenotransplants of animal cells, tissues or organs into humans are already occurring, with patients paying large sums of money to travel overseas and receiving approved treatments around the world.

But not so in Australia. Australians must either wait or join the growing number of “xenotourists” who face the stark reality that their only option for a potential life-saving medical cure lies halfway across the world.

Xenotourism is where someone travels to another country for a xenotransplant. Anecdotal evidence indicates that more people are choosing this option to treat conditions such as diabetes, and then returning to live in countries where the procedures are not yet approved, rather than waiting for governments to legislate in favour of new treatments.

The use of animal cells in medical treatments is not new. In fact, pig insulin has helped treat diabetics for almost half a century. The genetic make-up of pigs is remarkably similar to humans and, as such, has always provided a valuable alternative source of insulin.

In late 2004, Australia’s National Health and Medical Research Council (NHMRC) recommended a continuation of a moratorium banning whole animal organ transplants for five years, although it publicly said it was “undecided” about whether to allow animal cell and tissue transplants into humans. The NHMRC did acknowledge the “lower potential risk of infection and higher expected benefit to humans” of animal cell transplants.

However, in March 2005 the NHMRC stated that xeno cell treatments would not go ahead until more evidence allaying safety concerns was produced.

In the past decade extensive research has been conducted, including an international study in 1999 that reported no transfer of pig viruses in 160 human patients treated with living pig tissue.

Nevertheless, the moratorium in Australia remains. In New Zealand, the regulatory authorities have called for widespread public comment on the issue. After extensive community consultation, New Zealand’s BioEthics Committee released a detailed report in late 2005 recommending that xenotransplantation proceed on a case-by-case basis.

Why Not Human Cells?

Since the early 1900s, living cells have been used to restore or replace lost or damaged tissues due to disease or injury. Human cell transplants have provided significant hope for several diseases, but the critical shortage of donated human organs has not made this a viable therapeutic reality. This is why the spotlight has now turned to alternative cell sources.

In Australia there are more than 130,000 people with Type 1 diabetes. Contrast this against an average of 200 organs donated annually. In the case of diabetes, two or three donor pancreases are needed for each transplant. The equation just doesn’t add up.

However, pig cells are remarkably similar to human cells, and are also relatively easy to obtain in large numbers. Diabetics, for example, have been using pig insulin for more than half a century because of its similarity to human insulin.

After more than a decade of virology research since some safety concerns were raised, significant pre-screening and monitoring is in place, and pig cells pose less risk than many other potential therapies.

Pig tissues, cells and blood products are already used throughout medicine. The fields of orthopaedics, cardiac surgery, and plastic and reconstructive surgeries are all turning to pigs as a viable alternative. Since the 1950s more than one million people have been transplanted with pig heart valves without any infection-related disease problems.

However, not every pig is suitable. For organ and cell transplants in particular, a high-health status pig herd is essential.

Australian-listed company Living Cell Technologies Ltd (LCT) uses pigs sourced from the Auckland Islands, located halfway between New Zealand and Antarctica. These pigs were originally placed on these islands 200 years ago as a food source for passing sailors. Some 150 years of breeding in isolation and extreme climatic conditions have created a natural quarantine zone, ensuring that the pig herd is free from infectious microorganisms.

To reach a high health status, pigs must be free from common viruses and disease and kept under very strict conditions. It takes at least three generations, with pigs being fed on a specialised diet and contained in specialised barrier facilities (designated pathogen-free) with filtered air, waste disposal and restricted access systems. LCT has all these in place.

The LCT Virology Department has submitted tissue samples to recognised experts in the USA, Australia, Germany, Canada and Spain to verify the high health status of the pigs, and the findings have been confirmed. In international benchmarking studies, no other pig herd has been found to be as appropriate for human therapeutic use.

What’s Happening Now?

While Type 1 diabetes patients are sometimes able to manage their lives through a complex regime of multiple daily insulin injections, the sufferers of debilitating incurable diseases such as Huntington’s disease are not so fortunate. With no available treatment, their impatience with policy-makers is understandable when a possible clinical trial in their home country is unlikely to take place solely because it uses animal cells.

For LCT the moratorium has meant going offshore to conduct clinical trials. The company recently announced that it has regulatory and ethics approval to start a phase I/IIa clinical trial in Type I diabetes in Russia using the services of a US-based contract research organisation. In October 2008 approval was gained to conduct a phase I/IIa clinical trial in New Zealand.

For LCT this is not new ground. Ten years ago, LCT conducted a human clinical trial of an earlier prototype of this diabetes product in New Zealand. One of the patients showed a 30% reduction in his insulin requirements despite receiving only one-third of the dose now thought to be necessary. The patient also didn’t experience major hypoglycaemic episodes after receiving the transplant, making his diabetes easier to manage.

However, the trial was halted because limited research suggested that pig retroviruses could infect human patients. After years of careful research these fears have been allayed and LCT is ready to once again prove the effectiveness of this novel product.

With the original transplant recipients in New Zealand leading healthy lives free of infection, the signs are promising. One transplant patient has been monitored over

10 years and still has pig insulin in his blood, showing that the pig islet cells are indeed still present and capable of producing insulin.

The US Food and Drug Administration (FDA) has already demonstrated a willingness to support xenotransplantation, allowing animal tissue treatments, such as one for Parkinson’s disease, to proceed. The advantages in being first in biotechnology are significant. Waiting for other countries to give the all-clear and establish regulatory frameworks, rather than becoming an active partner in developing the appropriate checks and balances on xenotransplantation, will only see the relocation of investment dollars and intellectual property overseas.

The cures for diabetes and neurodegenerative diseases are extremely lucrative, but companies and researchers located in Australia will miss the opportunity if they are not supported by policy-makers. Their only option is to relocate if they want to advance their research into the human trial phase.

The future for pig-based therapies looks bright, just not in Australia.

Reprinted from Australasian Science (