GTC Biotherapeutics said regulators cleared its drug ATryn, which is manufactured using milk from goats that have been scientifically altered to produce extra antithrombin, a protein that acts as a natural blood thinner.
The drug's approval may be the first step toward new kinds of medications made not from chemicals, but from living organisms altered by scientists. Similar drugs could be available in the next few years for a range of human ailments, including hemophilia.
The FDA cleared the drug to treat patients with a rare hereditary disorder that causes a deficiency of the protein, putting them at higher risk of deadly blood clots. The injectable treatment will be marketed in the U.S. by Deerfield, Ill.-based Ovation Pharmaceuticals
About 1 in 5,000 people don't produce enough antithrombin protein, according to Framingham, Mass.-based based GTC. As a result, their blood is more likely to stick together, occasionally causing clots that can travel to the lungs or brain, causing death. Pregnant women with the disorder are at higher risk of miscarriage or stillbirth, because of blood clots in the placenta.
Patients with hereditary anithrombin deficiency are currently prescribed conventional blood thinners, like Plavix from Bristol-Myers Squibb and Sanofi-Aventis. That will not change with the new approval. ATryn is only approved for use when patients are undergoing surgery or having a baby, times when the risk of dangerous clots is particularly high. Those patients would receive the drug by intravenous infusion for a limited time before and after their procedures.
To make the drug, scientists at GTC put DNA for the human antithrombin protein into single cell embryos of goats. Goat embryos with the gene were then inserted into the wombs of surrogate mothers who gave birth to baby goats that produce the protein-charged milk.
Genetically engineered animals are not clones but rather animals that have had their DNA changed to produce a desirable characteristic.
