Insulin produced by genetically modified plants - with a human gene added - could be on the market in three years, a Canadian company has claimed.
By Hugh Levinson
Sembiosys said it has made scientific breakthroughs and found a short cut through current drug regulations.
The firm's CEO Andrew Baum said his company could become one of the first to sell a plant-based pharmaceutical.
However, critics believe that these products pose greater environmental and health risks than GM food crops.
Most insulin is now produced by genetically modified bacteria, inside sealed tanks. The new technique uses GM plants grown out in the open.
The company is growing insulin in the seeds of safflower, a relatively little-used seed oil plant. The safflower is being grown on a trial basis in fields in Chile, the US and Canada.
Their crop is grown counter-seasonally to reduce the risks of the insulin-producing genes crossing to other plants.
Mr Baum said: "Sembiosys believes it will be one of the first - or the first - company to get a plant-based pharmaceutical on the market."
Sembiosys has predicted an "explosion" in demand for insulin because of a growing number of diabetics. Moreover, new methods of delivering the drug, like inhalation, require more insulin per dose than injections.
Mr Baum said that one large North American farm growing his safflower could meet the global demand for insulin - and that the price of the drug could be cut significantly.
If the firm can demonstrate that the plant-based insulin is identical with human insulin, it won't have to go through all the long and costly stages of full clinical trials.
Mr Baum said he saw his product as part of a new wave of GM plants which could help change public opinion - particularly in Europe - in favour of the technology.
He said: "While the first wave of products were really focussed on the farmer and improving agricultural economics, there's an increasing emphasis now in the industry on products that address more direct consumer benefits and consumer needs."
There are also more projects under way to develop many other pharmaceutical crops.
Professor Ed Rybicki of the University of Cape Town has modified tobacco so it produces a vaccine for cervical cancer. He said the aim was to help women in the developing world.
Tobacco has been modified with a fluorescent marker gene
Furthermore, there are plans to produce spider silk from potatoes and to make non-polluting engine lubricants in seed oil plants.
A Danish company is even trying to create plants that will help clear minefields. The flowers of the modified thale cress would change from white to red if their roots absorb traces of explosives - showing where the landmines had been laid.
However Clare Oxborrow, of Friends of the Earth, said the risks of contamination from pharmaceutical plants was actually greater than from food crops.
She said there had already been contamination incidents with experimental pharmaceutical plants.
One American company, Prodigene, was heavily fined for its mistakes in 2002. Similar problems have occurred recently with GM food crops.
She said: "It's worrying enough when it's a crop intended for human consumption.
"But when it might be a pharmaceutical crop in the future that contaminates the food chain, that raises serious worries and questions about the risks involved for human health."
Ms Oxborrow said the promised benefits would not be great enough to shift public opinion.
She pointed to many other factors influencing public views - like the impact on the environment, potential health concerns and corporate control of the food chain.
However Mr Baum insisted: "The goodness of what we're doing is so clear - people who are dying of diabetes in the developing world will eventually get insulin - that I think people can understand it."
Hugh Levinson and Susan Watts' radio documentary on GM insulin research can be heard on BBC Radio 4 at 2000GMT/2100BST and their film on the subject can be seen on Newsnight at 2130GMT/2230BST on BBC Two, both on April 4 2007.