Old MacDonald and the Pharm? In a decision that could lead to future herds of genetically modified livestock, on Friday, the U.S. Food and Drug Administration approved the first drug produced by livestock that had been given a human gene. The drug, called ATryn, is made by GTC Biotherapeutics of Framingham, Mass., and will be marketed by Ovation Pharmaceuticals later this year to prevent blood clots in people with a rare hereditary blood disorder.
In addition to approving the drug, the FDA also put its seal of approval on the goats used to make it, the first animals cleared under guidelines adopted last month regulating the use of transgenic animals in the American food and drug supply.
About one in 5,000 Americans lack a protein called antithrombin. People with a hereditary deficiency are at high risk during surgeries and childbirth. The protein, which until now has been extracted from human blood donations or grown in vats from genetically engineered cells, is sometimes in short supply. GTC scientists inserted DNA for the human antithrombin protein into single-celled goat embryos. Then they implanted the embryos into surrogate does. The resulting goats are able to produce high levels of antithrombin in their milk. The company maintains a herd of 200 of the bioengineered goats on a central Massachusetts farm. The company says each one can produce as much antithrombin in a year as can be derived from 90,000 blood donations.
"With FDA approval of ATryn, we can help ensure that patients with hereditary antithrombin deficiency, a rare clotting disorder associated with severe complications, have access to much-needed therapy," said Jeffrey S. Aronin, Ovation president and CEO.
The FDA's actions have raised eyebrows, however. "On the one hand, it's refreshing that this first application has been done on a small scale in a very confined environment and, from a practical point of view, with a very safe process," said Gregory Jaffe, biotech project director for the Center for Science in the Public Interest. "It doesn't seem that the animals are hurt by the process, and the likelihood of these goats getting into the food supply is very slim. So in some ways, this is a good test case."
On the other hand, the regulatory process is not stringent enough regarding environmental issues, Jaffe said. "In our opinion, the process is not transparent enough for a technology as controversial as this one is," he said.