Old MacDonald’s Pharma

February 9, 2009 – 4:06 pm by Colette Pilkus

The ads say milk does a body good, but what about goats milk? It does if you have a history of blood clots.

In a scientific first, GTC Biotherapeutics has changed the genes of goats to produce milk rich in antithrombin, a protein that acts as a natural blood thinner in humans. The process for producing ATryn involves scientists inserting DNA for the human antithrombin protein into a single-celled goat embryo. This embryo is implanted into a surrogate doe. The resulting transgenic offspring are able to produce high levels of antithrombin in their milk. This protein is collected and purified from the milk to produce ATryn, which is administered to patients by intravenous infusion.

On Friday, ATryn was approved by FDA to aid those with an unusual hereditary disorder that caused accelerated vulnerability to blood clots. It is the first ever transgenically produced therapeutic protein and the first recombinant antithrombin approved in the U.S. Along with the approval of the drug, the FDA’s Center for Veterinary Medicine also approved GTC’s New Animal Drug Application, the first of its kind to regulate genetically engineered animals. This is now required for a recombinant technology used to develop transgenic animals, such as the goats that produce recombinant antithrombin.

Antithrombin is usually produced from human plasma collected from donors and sometimes runs in short supply or may even be unavailable. Making antithrombin from goats may be better, since it ensures a steady supply. GTC’s production comes from a herd of about 200 goats on a farm in central Massachusetts and the company said one of its goats can produce as much antithrombin in a year as can be derived from 90,000 blood donations. And if more antithrombin is needed, the herd can be expanded.

ATryn has already been approved for use in Europe.

Tags: animals, ATryn, blood clots, milk