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2-Plants: Safety of drug-producing GE crops questioned



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TITLE:  Safety of Drug-producing Plants Questioned
SOURCE: United Press International, by Steve Mitchell
        posted at U.S. National Library of Medicine
        http://www.nlm.nih.gov/medlineplus/news/fullstory_8587.html
DATE:   July 17, 2002

------------------ archive: http://www.gene.ch/genet.html ------------------


Safety of Drug-producing Plants Questioned

WASHINGTON, Jul 17, 2002 (United Press International via COMTEX) -- Drugs 
produced via genetically engineered plants could soon be available to the 
public, representatives from the federal government and the pharmaceutical 
industry said at a meeting Wednesday, but the plants' impact on the 
environment and human health remains unknown.

Anne Vidaver, chief scientist at the U.S. Department of Agriculture, told 
United Press International it "would not be surprising" for drugs grown in 
plants to be on the market in a few years.

Kathryn Stein, a former Food and Drug Administration official for 22 years 
and now with Macrogenics, of Rockville, Md., which is developing plant-
based pharmaceuticals, concurred. "Drugs produced from (engineered) plants 
will be on the market," she told UPI. "There's no question in my mind."

As many as 20 companies are attempting to develop drug-producing plants and 
approximately seven products are in advanced clinical trials in humans, 
Mich Hein, president of Epicyte, of San Diego, told UPI. Epicyte expects to 
head into clinical trials in 2003 with its anti-herpes product, which is 
produced in plants.

To produce drug-yielding plants, genes for human hormones, enzymes or 
antibodies are inserted into conventional plants such as corn and spinach. 
The plants will produce the desired drug product, which then can be 
purified from the plant and used to make drugs.

Drugs produced in plants have the potential to treat cancer, infectious 
diseases, heart disease and disease caused by biowarfare agents, Hein said.

Most companies in this field are focusing on a type of drug called 
monoclonal antibodies, designed to bind to disease-causing or harmful 
viruses, bacteria or other agents and prevent them from negatively 
impacting the body. There currently are ten monoclonal antibodies approved 
by the FDA, including the breast cancer treatment Herceptin and the 
rheumatoid arthritis treatment Remicade.

However, the current method of making these products has reached the limits 
of its capacity and plants appear to be a promising way of increasing that 
capacity and lowering production cost, said Richard McCloskey, vice 
president of medical research at Centocor, of Malvern, Pa.

Many companies plan to use corn to produce the drugs, which raises concerns 
about the unknown potential for seeds or pollen from these plants 
contaminating nearby food crops and finding their way into the environment 
or possibly unsuspecting humans.

This prospect is in the forefront of the minds of pharmaceutical company 
and regulatory agency officials, due in particular to StarLink, a 
genetically modified corn intended for growing crops for animal feed that 
accidentally found its way into human food crops and several different food 
products in 2000.

Industry and regulatory agencies doubt such an event could happen with corn 
used for producing drugs, however. "Pharmaceutical-producing corn will 
never be seed corn for anything," Stein said, so it would be highly 
unlikely it could get mixed up with seeds for human or animal feed. Stein 
said she would want every kernel accounted for because each one would 
contain valuable drug product.

USDA's Vidaver also said plant pharmaceuticals would entail a different 
situation than StarLink. "Companies will be extra-cautious" because the 
crops would contain pharmaceuticals and as such would be very valuable. 
Companies also would not want to risk damaging their reputations by having 
a product linked to contamination of the environment or human food supply, 
she said.

Bill Freese, policy analyst with Friends of the Earth, said "there are real 
problems with growing (drug-producing) crops in the open air." The main 
risk is the contamination of food crops with pharmaceuticals, Freese told 
UPI, noting corn pollen can travel for more than a mile. Few, if any, 
studies have been done to examine the potential health risks to consumers 
or farmworkers harvesting drug-producing crops or the impact on animals, he 
said.

Jane Rissler of the Union of Concerned Scientists agreed. From the few 
studies that have been done, she said it is reasonable to conclude "some, 
perhaps many pharmaceutical-producing food crops might pose risks to 
humans." She added current governmental regulations do not protect humans 
or the environment from these risks.

There also is little monitoring by the USDA and the companies themselves 
contract the work to farmers who "sometimes are not even aware of what 
they're growing," Freese said. The USDA maintains a list of drug crops 
being grown but it does not reveal the location of the crops or the type of 
drug being grown in the crop, Freese said.

This leaves little information available to the public and this could 
ultimately come back to haunt pharmaceutical companies, Rissler said. 
"Having the public in the dark ... does not inspire confidence especially 
in light of experience in last few years with StarLink," she said.

However, Philip Eppard of Monsanto, which is developing pharmaceutical-
producing crops, said industry is taking steps to safeguard the public 
because it "cannot afford another StarLink type of incident." Seeds for 
pharmaceutical-producing crops are never sold, he said. They are securely 
transported and security measures are utilized around the crops to prohibit 
tampering. In addition, the plants are detassled or sterile males are used 
so there is no transgenic pollen available for release into the air that 
could cause contamination in far away crops, he said.

Gregory Jaffe, director of the biotechnology project at the Center for 
Science in the Public Interest, told UPI he wants pharmaceutical plants to 
go forward because they have great potential to provide life-saving drugs. 
But he agreed with Rissler and Freese that the government has dragged its 
feet in creating appropriate regulations for these products.

Keith Webber, acting director of the FDA's division of monoclonal 
antibodies, said the agency in conjunction with the USDA will soon be 
issuing guidelines to industry for developing drugs derived from 
bioengineered plants. One of the concerns the FDA has is residual 
pesticides, herbicides or plant toxins that may remain in the final 
product, Webber said.

USDA's James White said his agency already has developed containment 
strategies to ensure the bioengineered corn does not leach into the 
environment or affect other crops. This includes ensuring that there is no 
other corn within a half-mile of the pharmaceutical-producing plants and 
the crops must be planted 21 days after other nearby crops to reduce the 
likelihood that pollen from the bioengineered crop could contaminate food 
crops.

White noted these criteria are "difficult or virtually impossible to meet 
in the corn belt." 

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