
Plants spiked with extra genes are being harvested for
drugs.
Margot Roosevelt/San Diego
The scraggly cornstalks sprouting from pots in Andy Hiatt's laboratory
don't look particularly unusual. But woven into their DNA is a tiny strip
of mankind: a human gene that codes for an antibody to a sexually
transmitted disease--genital herpes--that afflicts some 60 million
Americans. When the corn plants mature and produce kernels, Hiatt's
company, Epicyte Pharmaceutical of San Diego, hopes to turn them into a
topical gel for herpes.
And that's just for starters. Epicyte is one of a host of biotech companies
that have seized on the information in the map of the human genome--a map
that was officially declared complete last month--to create all manner of
plant-based pharmaceuticals. Researchers have launched more than 300 trials
of genetically engineered crops to produce everything from fruit-based
hepatitis vaccines to AIDS drugs grown in tobacco leaves. They call this
biopharming.
Critics--and there are many--have another name for it. They call it
Pharmageddon. Environmentalists are worried that the unnaturally combined
genes, when loosed upon the ecosphere, will spread like genetic kudzu.
Consumer advocates, who have never warmed to today's genetically modified
foods, fear that plant-grown drugs and industrial chemicals will end up on
their dinner tables. Hoping to head off a public revolt, the Federal
Government is putting the finishing touches on new regulations aimed at
reassuring the grocery industry that human-based crops will not contaminate
the food supply.
But the proposed rules are not satisfying the critics or slowing the
biopharmers. Open-air trials of pharmaceutical crops have taken place in 14
states, from Hawaii to Maryland. A Texas firm is selling a corn-bred enzyme
that stimulates insulin production in diabetics. Clinical trials have begun
for experimental crop-grown drugs to treat cystic fibrosis, non-Hodgkin's
lymphoma and hepatitis B. "Molecular farming represents the pharmaceutical
industry's best opportunity to strike a serious blow against such global
diseases as AIDS, Alzheimer's and cancer," says Francois Arcand, president
of the Conference on Plant-Made Pharmaceuticals, held in Quebec City
earlier this year.
What's driving this effort to morph fields into drug factories? In a word:
cost. In the past decade, the DNA revolution has spawned a generation of
drugs made from human antibodies, the proteins that white blood cells use
to defend the body against disease. Today such "biologics" are cultivated
in huge fermentation vats, often by painstakingly planting cloned human
cells in such unlikely breeding sites as the ovary cells of Chinese
hamsters. Building one of these sophisticated biofactories can take as long
as seven years and cost up to $ 600 million.
Achieving the same results through biopharming--splicing antibodies into
the genetic fabric of plants, growing them in fields and extracting and
purifying them--could cut costs by half. "If you don't have to spend half a
billion, then more products can advance to the marketplace," says Arizona
State University researcher Charles Arntzen. The opportunities, he points
out, are not limited to human drugs. Arntzen foresees rich markets for
plant-grown vaccines to protect fish and poultry against diseases now being
treated--and in many cases overtreated--with conventional antibiotics.
So far, more than two-thirds of plant-based medicines are being tested in
corn--a plant whose genetics is well understood. But the perils of using
food crops became clear last December when the U.S. Department of
Agriculture (USDA) ordered the incineration of 500,000 bushels of soybeans
in Aurora, Neb. The soybeans, from a plant used in everything from baby
food and margarine to ice cream, were inadvertently mixed in a silo with
corn that was genetically engineered by a Texas firm, ProdiGene Inc., to
produce a vaccine against pig diarrhea. "Drugs have side effects," says
Jean Halloran of the Consumers Union. "They should not turn up in our
cornflakes."
The pig-diarrhea incident rattled the industry. Some major players, among
them Dow and Monsanto, are steering clear of the Farm Belt, preferring to
grow their pharmacorn in isolated areas of Arizona, California and
Washington State. Even so, the USDA--under pressure from Midwestern
politicians who dream of biopharm Silicon Valleys in Iowa--has stopped
short of restricting biopharming in major corn-growing states. Its new
rules would step up inspections of biopharms and expand the buffer zone
between genetically modified corn and food crops to a mile. But opponents
say that's not wide enough to prevent cross-pollination, and a coalition of
11 environmental groups is filing suit against the Agriculture Department.
They want to ban the use of food crops for pharmaceutical uses and restrict
the plants to greenhouses. If such measures were enforced, argues Jonathan
McIntyre, chief scientist for Monsanto Protein Technologies, "it would set
back the industry 12 to 20 years."
At Epicyte's spotless laboratory, Hiatt is taking no chances. Tiny tobacco
leaves injected with herpes-antibody genes fill the incubators--a backup,
he says, in case corn is outlawed. And the company is branching out,
developing plant-grown antibodies to fight respiratory syncytial virus,
treat Alzheimer's, battle weaponized Ebola and even attack sperm--a kind of
biopharm birth control.
By the end of the decade, biopharmaceuticals are projected to grow into a $
20 billion industry. But how many of the new drugs will be manufactured in
living plant-factories remains uncertain. "There has been an emotional
response to the technology," says Hiatt. "But if we can bring down the cost
of treating these diseases, the drawbacks compared with the benefits will
be minuscule."
BOX STORY:
BUMPER CROP OF FRANKENPLANTS
Environmentalists' objections have not stopped researchers from launching
more than 300 trials of crops genetically engineered to fight diseases.
Among them:
TOMATOES AND POTATOES Hepatitis B, coliform disease, Norwalk virus, cholera
TOBACCO The common cold, Fabry's disease, non-Hodgkin's lymphoma
CORN Cystic fibrosis, dental cavities, diabetes, surgical blood loss, diarrhea
RICE Lysozyme for gastrointestinal health, topical infections and
inflammations; alternative to antibiotics in poultry diets
A modern drug biofactory can take seven years to build and cost $ 600
million. Growing the same drug in a field could cut costs in half
** NOTICE: In accordance with Title 17 U.S.C. Section 107, this material
is distributed for research and educational purposes only. **
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Last Updated on 5/27/03 |
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