'Pharming' -- for medicinal purposes only

July 23, 1996|By Walter Truett Anderson

EVEN AS YOU'RE straining to add all those new words from the world of computers to your vocabulary, try this one from biotechnology -- ''pharming.''

You've seen it in gee-whiz news reports about the bio-engineered cow that gives medicinal milk, or the new kind of tobacco plant that helps cure, rather than cause, cancer. What you may not know is that pharming -- the manufacture of medical products from genetically modified plants or animals -- is growing by leaps and bounds. And unlike the computer, which so far has mainly benefited the developed world, pharming's biggest beneficiaries may be the world's poorest regions -- those left largely behind by advances in science and technology.

Among pharming's most promising products are sheep's milk containing a protein that can be used to treat emphysema, and a goat's milk with a human antibody useful in cancer therapy -- both now in chemical testing stages. Then there's a sunburn preventive made from a genetically modified tobacco plant that is just now reaching the market. But pharming's most revolutionary product is likely to be edible vaccines -- foods that can confer immunity to certain diseases.

Take the banana. As a pharming product, this tropical fruit is being transformed, according to Charles Arntzen of the Boyce Thompson Institute for Plant Research, into an inexpensive vaccine-delivery system.

Working with tobacco, Dr. Arntzen and his colleagues have already obtained a hepatitis B vaccine that is chemically the same as the kind now produced commercially, at high cost, from serum derived from infected blood or by fermenting genetically engineered yeast. Their next step was to produce plant vaccines that could be eaten instead of injected. By far the most successful is a potato that, when fed to laboratory mice, makes them immune to cholera and other diarrhetic diseases.

The potato vaccine is now moving to the human testing stage. The only problem is that few humans -- especially babies -- are willing or able to eat the raw potato, but cooking destroys the antigen. So the project is now growing an experimental crop of bananas with the same antigen.

Such a banana vaccine would have an immeasurable impact on the health of the developing world, where diarrhetic diseases cause up to 10 million deaths annually, particularly among children.

New industries

The impact would be equally great on the economic side, giving impoverished countries the potential for what amounts to a low-cost, low-tech domestic vaccine-production industry. Since bananas don't require refrigeration, there would be no storage problem -- a high-cost item for ordinary vaccines, which need to be stored at low temperatures.

Other researchers are looking at a wide range of possible food-based vaccines. Some are extreme longshots -- an AIDS vaccine, for example, or an edible vaccine against the bacteria that cause tooth decay. And there's the growing field of agro-pharmaceuticals -- medicines produced by pharming that aren't vaccines.

Big companies like Bayer and Bristol Meyers are pouring a lot of money into research on pharm products because they figure pharming will be, in the long run, a much cheaper way to produce vaccines.

A study by researchers at Iowa State University estimates animal pharming to be ''five to ten times more economical on a continuing basis and two to three times cheaper in start-up costs than cell-culture production methods.''

Given this economic incentive, it is entirely possible that some methods of producing vaccines could become obsolete. The serum method of producing hepatitis B vaccine was already superseded by the biotech method of fermenting genetically modified yeast, and that in turn could well be superseded in the near future by a vaccine made from plants.

While this undoubtedly will set off competitive flurries in the industrialized world, it could also set the stage for a major new agricultural industry in the least developed regions of the world. Even as some counties may have a long way to go to get a computer in every village, they may be far closer to developing tobacco farms, banana plantations and herds of genetically modified goats -- the chemical factories of the future.

Walter Truett Anderson, author of numerous books exploring future trends, wrote this commentary for Pacific News Service.

Pub Date: 7/23/96

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