- Human trials of vaccines produced by genetically modified
plants could begin within five years, scientists claimed yesterday.
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- The researchers outlined proposals to grow fields of
crops that have been genetically modified to produce vaccines and other
pharmaceuticals to treat HIV, rabies, diabetes and TB.
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- They said field trials of medicine-producing crops were
likely to begin in 2006, with safety trials in humans beginning three years
later at St George's hospital in London.
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- Although the team will consider carrying out trials on
plots of a hectare (2.5 acres) in Britain, the unfavourable climate and
risk of sabotage mean that field studies, and ultimately full-scale growing
of the plants, is most likely to happen in South Africa or southern Europe.
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- Scientists have long known that GM technology can be
used to trick a plant's molecular machinery into making a range of medically
useful compounds. Instead of using expensive pharmaceutical factories,
advocates envisage fields of GM crops being harvested to reap new medicines
cheaply, a process known as "pharming".
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- According to Julian Ma of St George's Hospital Medical
School in London, the leader of the £8m project, the primary aim
is to provide medicines for the developing world. "The major burden
of disease is in the developing world, but these are the countries that
do not have access to vaccines," Prof Ma said.
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- The number of people dying each year from the six major
diseases for which vaccines exist is around 3.3 million.
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- The scientists have already identified genes that can
be put into plants to make them produce antibodies or other compounds that
can help treat rabies, TB and diabetes.
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- While no vaccine yet exists for HIV, genes that produce
antibodies capable of destroying the virus have been discovered.
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- A cream containing the antibodies could help reduce the
risk of HIV being transmitted during sexual intercourse, but the production
technology cannot easily be scaled up.
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- "Using traditional techniques, you just cannot produce
enough," said Prof Ma.
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- Prof Ma believes GM plants - probably tobacco or maize
- offer a cheap way to make vast quantities of vaccines and other drugs.
"It looks like the cost of plant-derived products will be 10- to 100-fold
less than conventionally derived products," he said.
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- If the technique is proved, it may be adopted by developing
countries, helping to breaking their reliance upon pharmaceutical multinationals.
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- "Growing and harvesting plants is low tech,"
Prof Ma said. "We see this as being transferred to countries where
they can start up their own industry at a low start-up cost and produce
the amounts they need."
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- Philip Dale, an expert in GM safety issues at the John
Innes Centre in Norwich, is advising on possible risks of contamination,
where genes from the GM plants get into others.
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- "The ability to be able to isolate these from other
crops is a crucial factor," he said. "There's a possibility of
mixing with other crops and that's the basic challenge we have to wrestle
with."
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- Land used to grow the crops will need to be remote from
other crops and dedicated machinery will be needed to process them, so
that the medicine cannot enter the food chain.
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- Sue Mayer of the lobby group GeneWatch said the researchers
should pledge to make their technology free to all, to prevent it being
claimed by pharmaceutical companies.
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- Friends of the Earth's GM campaigner, Clare Oxborrow,
said: "A clear set of criteria must be established to ensure that
human health and the environment are protected. Any benefits must genuinely
reach those that need them, rather than simply lining the pockets of the
biotech and pharmaceutical industry."
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- Guardian Unlimited © Guardian Newspapers Limited
2004 http://www.guardian.co.uk/gmdebate/Story/0,2763,1259866,00.html
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