Genetic engineering of food crops to produce drugs raises concerns

Tom Horan, a farmer based in Iowa, is excited about the possibilities of producing drugs from his corn acreage. Speaking at a recent conference at Iowa State University, Horan described how he grows a small field of corn that has been genetically engineered to produce a drug for treating cystic fibrosis. A European company, Meristem Therapeutics, developed the GM corn. Horan believes that more Iowa farmers should capitalize on the opportunities for growing these "value-added" crops.

Contamination could be a major problem

While Horan sees great opportunities, others see potential problems with the rapidly expanding development of so-called "pharma" crops. It is no surprise that biotech activists have sounded alarms, but it is noteworthy that biotech proponents are also expressing concerns. Walt Fehr, director of biotechnology at Iowa State University, told Food Traceability Report Weekly that any genetic contamination of corn used for feed is a major problem in Iowa and that separating pharma crops from food crops in the field has problems. Fehr suggested that it might be better to avoid the use of food crops for pharmaceutical production altogether.

Dirk E. Maier, professor of agricultural and biological engineering at Purdue University released a fact sheet, stating, "the fact that transgenic grains and oilseeds for use as pharmaceutical drug carriers and industrial chemicals may be making their way into a field near your farm, grain elevator, feed mill or processing plant should be a concern," especially in light of the Starlink corn contamination debacle in 2000.

Pharma crops grown in U.S.

According to Maier, ProdiGene, a biotechnology company based in College Station, Texas, has produced four pharma GM corn varieties and another GM variety that produces an industrial enzyme. These five varieties have been released commercially and are grown by a select group of farmers on a few hundred acres in the Midwestern United States (see The Non-GMO Source, June 2002). ProdiGene has also developed a GM corn variety that contains a protein found on the surface of HIV, the virus that causes AID. The company intends to use the GM corn as an oral vaccine for AIDS through corn-based products.

Meanwhile, other GM pharma and industrial crops are in the pipeline and expected to be ready for approval and commercial release within a few years. These include a GM corn variety that produces a drug for treating herpes, a crop that will produce antibodies for therapeutic blood products, and oral vaccines for human and animal diseases. Maier states that U.S. seed companies that work with biotech firms are recruiting farmers, such as Bill Horan, to grow the crops. In addition, international companies, such as Meristem Therapeutics, are buying acreage in the Midwest for field-testing.

According to the Genetically Engineered Food Alert, more than 300 open-air field trials of pharma crops have already been conducted in unidentified locations across the U.S., particularly in the Midwest.

Drugs in cornflakes?

Maier, Fehr, and the activists are concerned that pollen from these novel GM corn varieties will cross-pollinate with conventional and food corn varieties, thus causing another, and possibly even worse, "Starlink" type problem. More troubling, the drugs could enter the food supply and cause toxic or allergic reactions in human beings. As Larry Bohlen, director of health and environment programs at Friends of the Earth, says, "Just one mistake by a biotech company and we'll be eating other people's prescription drugs in our corn flakes."

According to ProdiGene's director of marketing, John McClellan, the pharma corn varieties are grown under a strict "identity containment" system, which at first glance seems nothing more than a system of identity preservation with isolation distances from other crops, field inspections, audits, and dedicated equipment used only for that crop.

Bill Horan grows his pharma crops on a small plot in the middle of a field of soybeans. On each side of the corn rows is a fallow strip of soil 100 feet wide providing further separation. Horan plants the corn 30 days later than his neighbors do. He is confident there will be no contamination. "We want zero tolerance," he says.

Doubts about containment

Despite such assurances, Maier expressed doubts about the ability to contain pollen flow, "experience and science-based research tell us that no identity preservation system will ever be able to contain 100% of every seed kernel, plant pollen and grain kernel generated from crops grown in agricultural fields."

USDA's Animal and Plant Health Inspection Service (APHIS) is responsible for regulating pharma crops. A recent report by the National Academy of Sciences states that "the current APHIS review process will need to improve to deal with the risks of future modified crops … engineered to produce substances for non-food uses, such as pharmaceutical products." Maier says that APHIS's voluntary regulation of pharma crops is a "flawed approach." He states, "The major world food and feed staple crops should not be used for transgenic modifications for the purpose of expressing pharmaceutical ingredients and industrial chemicals, unless they can meet food safety requirements."

The USDA recently announced that it would tighten its regulations on pharma crops by increasing the isolation distances up to one-half mile and requiring the crops to be planted three weeks before or after conventional corn. APHIS also added a fine of up to $500,000 for violators.

Jane Rissler, deputy director/senior staff scientist, food and environment program at the Union of Concerned Scientists, still has doubts, telling the Des Moines Register, that the government is "unprepared" to regulate pharma crops. "They're talking about cancer drugs, potent drugs, drugs that are active in very small amounts. It's potentially troublesome to think of these genes falling into the food supply, like StarLink," she says.

Maier ends with a similar warning, "If the federal government does not intervene with threshold limits and stricter regulation and oversight soon, it will be just a matter of time before trace amounts of unapproved and non-food/feed-safe pharmaceutical and industrial proteins will be detected in our domestic and export food and feed market channels. This potential scenario will likely cause a far greater public outcry than did the StarLink discovery in taco shells."
(September 2002)