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Friday, Jul 10, 2009
And genetically modified his goats and chickens to produce drugs for humans. But hold on. Should we be doing this to animals?
By Elizabeth Svoboda
Read more: Environment, Politics, Science, Genetics, News, Animals, Environment & Science
Salon composite
June 11, 2008 | CHARLTON, Mass. -- Encompassed by pastoral green fields, the headquarters of GTC Biotherapeutics looks like any other New England farmstead. But its serenity is deceiving. Behind barn doors, the farm's most valuable employees -- a herd of pygmy goats from New Zealand -- are working round the clock, their milk glands churning out hundreds of gallons of high-grade pharmaceutical compounds.
The white gold extracted from the goats' udders will someday command big bucks in the American healthcare marketplace -- or so GTC hopes. The company's genetically modified animals possess a human gene that allows them to produce milk rich with a protein called antithrombin, which helps prevent blood clots from forming and staves off related conditions like heart attacks and strokes.
Tom Newberry, GTC's vice president of corporate communications, leads me into a corrugated-metal hutch. Goats enclosed in pens train inquisitive rectangular pupils on us and poke their heads through the bars. "They're looking for a handout," Newberry says, chuckling. But we can't give these goats kibble or even a pat on the head; that would be a breach of strict sanitary regulations.
ATryn, GTC's goat-derived antithrombin, cleared its first regulatory hurdle in 2006 when the European Commission approved it for sale in all 25 European Union countries. This past fall, GTC successfully lobbied the U.S. Food and Drug Administration to designate ATryn as a "fast-track product," making it eligible for accelerated review on this side of the Atlantic.
But GTC is out to prove it's no one-trick ruminant. Staff scientists have created transgenic goats that can churn out a smorgasbord of human proteins, including compounds that halt tumor blood-vessel development and blood-clotting factors for hemophiliacs. Protein-based human antibodies that protect against all kinds of diseases -- from SARS to incurable cancers -- could be next in the dairy pipeline.
A bevy of biotech companies is crowding the drug market with takes on the transgenic-remix concept. Origen, located in Burlingame, Calif., is developing a transgenic production line that employs chickens instead of goats as drug incubators. The company has bred birds that produce a range of human anticancer proteins and other antibodies in their eggs. In Athens, Ga., AviGenics is using a transgenic-chicken system to make a protein compound that stimulates the bone marrow to make more white blood cells -- essential in helping cancer patients bounce back after chemotherapy.
"Transgenic drug technology has been in the incubation stage for a long time," says Robert Kay, president and CEO of Origen. "But within the next five to 10 years, we should be seeing many new products in the clinic and pushing their way toward approval." Future drug-producing menageries, he predicts, will include pigs, cows and rabbits.
While these transgenic pioneers might seem to be cruising toward FDA approval, the road is hardly without obstacles. To the frustration of executives like Kay and Newberry, most of the snags are not financial or logistical but arise from people's reflexive reactions -- as in, Omigod, they're putting human genes into animals! It's "The Island of Dr. Moreau" made real.
But the revulsion to transgenic animals is more than reflexive; some animal biologists say biotech companies are overselling the safety of the resulting drugs. Meanwhile, ethicists question whether we should be restyling animals as drug producers at all.
GTC transforms goats into drug factories thanks to a recently perfected biological sleight of hand. Once a goat embryo is artificially fertilized in the lab, technicians zero in on the portion of the goat's genome that codes for a sugar found in goat milk and insert a human gene that codes for a naturally occurring protein. When the animal reaches maturity and begins producing milk, every cup of the white stuff contains large quantities of the therapeutic protein, which can be chemically extracted in pure form. "The mammary gland is nature's way of making proteins that are nutritious for offspring," Newberry says. "All we're doing is placing extra DNA coding in this natural pathway."
Before transgenic breeding, pharmaceutical companies normally extracted such protein compounds from donated blood plasma. But to get the same kilogram of antithrombin that a single transgenic goat produces each year, you'd have to get 50,000 people to donate blood -- a time-consuming process with its own inherent risks. "It's so bloody expensive, excuse the pun," Newberry says, "and the Red Cross just got hit with another set of fines for insufficient screening. Now, would you rather have a drug derived from human blood donors, or from our goats, given that we know where they slept last night?"
That question ignores a key fact. "Using goats for drug production has unpredictable effects, and the genetic inheritance of the modified genes is not a given -- 90 to 99 percent of the animals bred are killed immediately because they don't incorporate the desired gene," says Jessica Sandler, director of the regulatory testing division at People for the Ethical Treatment of Animals.
Creating transgenic animals does indeed have a high failure rate. With the technique known as pronuclear injection, only about one to 10 of every 100 attempts results in transgenic offspring, producing a high number of animals typically earmarked for euthanasia. The more sophisticated nuclear-transfer method that GTC uses ensures that virtually 100 percent of viable offspring are transgenic. Still, the transgene does not always land in the targeted section of the genome, and some offspring end up with severe birth defects for reasons that are still not well understood.
Tom Regan, a philosophy professor emeritus at North Carolina State University and author of "Empty Cages," sees the death and suffering of defective animals as a grave ethical misstep. "The animals used for these purposes are in fundamental ways like us -- their behavior tells us they're like us, evolutionary theory tells us they're like us," he says. "What we have with transgenic research is another incentive for reducing animals to something whose purpose for being in the world is to serve human interests. And that's fundamentally flawed."
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