GM pharming
The UK has no tolerance for GM crops in the food chain, but will it accept using them to produce drugs?2007-06-11 | By Paul Evans
Genetically modified crops have already come up against the brick wall of public opinion in Britain. The original movement to produce food crops genetically modified to be immune or resistant to herbicides or pests, or both, resulted in a huge media and public backlash.
For whatever reasons, be they superstitious or scientific, there is little tolerance from the UK public for manipulating the genetic make-up of natural products for the convenience or efficiency of farming.
But GM scientists have a new agenda; they are no longer concerned about improving conditions for traditional farming, they have moved on to the new pastures of pharming. Pharming is the process of growing and harvesting plants that have been genetically engineered with foreign DNA to make them produce medicine - or proteins which can be purified to produce medicine - at a fraction of the price of conventional manufacture. Scientists are currently growing plants with genetic instructions to make drugs for the treatment of diseases such as HIV, rabies and Hepatitis B, as well as crucial dietary supplements.
Scientists have long looked for ways to bring down the high costs of the extant procedures for drug production used by the world’s pharmaceutical industry. Big pharma companies’ bottom lines dictate that drug production tends to favour those parts of the world and sections of society which can turn medicines into profits. Pharming could turn that situation on its head.
There is still, of course uneasiness about the science. The Daily Mail, that self-appointed custodian of British public decency warns that there are “serious ethical concerns about such a fundamental interference with the building blocks of life.” But the argument from repulsion is much harder to make when the end product could mean saving the lives of millions in the developing world. Even anti-GM protestors, who destroyed a crop of GM corn plants in France recently, embarrassedly denied involvement when outraged patient groups revealed that the crops were being used to develop a protein used in the treatment of cystic fibrosis.
It should be remembered that the original GM drive promised to feed the world’s poor. If we allowed queasiness to countermand that drive, will the world’s sick fare any better?
The scientists involved are certainly passionate that their research may provide a unique solution to the world’s most serious medical problems. Professor Julian Ma, who heads a project at the Centre for Infection at St George’s Hospital in South London, to pharm potent drugs against HIV insists the benefits of pharming could give hope to millions: “The advantages they offer simply cannot be equalled by any other system. They provide the most promising opportunity open to us to supply low-cost drugs and vaccines to the developing world.”
Ma’s own project is to produce a drug called Cyanorvirin-N, which helps stop the HIV virus entering human cells. The St George’s team intend to develop the drug into a cream which can be applied by women in countries where men are unwilling to use condoms. He says: “If you’re a woman in sub-Saharan Africa, you’re not going to pay even a dollar or two a week for this. It has to be pennies, and that means it has to be produced in plants.” Ma estimates that 5 tonnes of the drug would be needed to provide two doses a week to 10 million – an amount way beyond feasibility for the production scale and economics of conventional drug manufacture.
His frustration with concerns such as those voiced in the Daily Mail is informed by an understanding of the part GM already plays in the health of millions of Britons. Growth hormones and insulin, routinely taken by diabetes sufferers in Britain, are made by adding the relevant human genes to bacteria used to produce human proteins – a fundamental interference with the building blocks of life that has been widely accepted since the 1980s. Ma explains: “From a scientific point of view there really isn’t anything special about plants with drugs in them. We can’t divorce the science from public attitudes, but life is all about risk assessment and it just isn’t feasible to make enough of these medicines in any other way.”
At the moment, Ma’s crops are grown in tobacco plants in a carefully controlled, windowless room on the roof of the hospital and in super-secure greenhouses in Kent, with a level of security Ma calls “ridiculous”.
Many feel that in order to sustain the levels of growth required for pharming to work it will be necessary to downgrade these security requirements and perhaps start growing proteins, for cheaper and quicker results, in food crops. The major benefit of pharming would be scale, but this last step may prove a major stumbling block. The possibility that GM crops pharmed to produce human proteins could escape into the food chain and contaminate entire food crops, is too large a risk for most.
Many feel that in order to sustain the levels of growth required for pharming to work it will be necessary to downgrade these security requirements and perhaps start growing proteins, for cheaper and quicker results, in food crops. The major benefit of pharming would be scale, but this last step may prove a major stumbling block. The possibility that GM crops pharmed to produce human proteins could escape into the food chain and contaminate entire food crops, is too large a risk for most.
It is on this particular point that even some of GM’s usual allies draw the line.
The UK’s New Scientist magazine has said that pharming food crops would be “daft” and “should never be tried in practice”. And an editorial in leading American pro-industry journal Nature certainly didn’t hold back in its searing criticism of such plans when it wrote: “It seems an industry in which the PhD is the intellectual norm is either incapable of learning a simple lesson from the past or cannot bring itself to act appropriately, despite what it has learned previously… This position is not anti GM – we should be concerned about the presence of a potentially toxic substance in food plants. After all, is this really so different from a conventional [drugs] manufacturer packaging its pills in candy wrappers?”
Ma is unperturbed, though, and suspects that the presence of human proteins (the Daily Mail’s building blocks of life) have led to double standards. He points to the fact that some British farmers grow rape seed to produce erucic acid, an additive for the plastics industry. “That is much more toxic than anything I grow.” He points to lysozome, a saliva protein engineered into rice by US company Ventria Bioscience in Kansas: “If you want to stop that getting into the environment you need to stop people spitting in the street.”
Pharmers have a number of ways of preventing this kind of cross-contamination including growing sterile varieties, fluorescent marks to identify stray seeds, and genetic tricks to stop the foreign genes appearing in pollen. GM pharmers themselves, unlike GM farmers, want to avoid cross-contamination. But for GM opponents these safeguards will never be enough. Ma hopes that the answer to changing attitudes will simply be to show the public what is possible: “The most important thing is to get that first product out there, then people will realise what we can do” he says.
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