EMA scientific committee backs first transgenic product ATryn

The anti-clotting agent ATryn (recombinant human anti-thrombin III) has become the first medicine derived from a genetically engineered animal to be recommended for marketing approval by the European Medicines Agency's scientific committee (CHMP).

The CHMP initially rejected the product, which is extracted from the milk of transgenic goats, but said it had now adopted a positive opinion supporting its use in patients with congenital antithrombin deficiency undergoing surgery, to prevent deep-vein thrombosis and thromboembolism.

In April 2005, GTC Biotherapeutics, said it had received a list of outstanding issues during the review of its Market Authorisation Application by the EMEA. This was followed by a CHMP negative opinion in February 2006. An appeal followed.

Last year, GTC and Denmark's LEO Pharma entered a collaboration agreement to develop and market ATryn for markets in Europe, the Middle East, and Canada. LEO assumed responsibility for sales and marketing of ATryn in all indications for the agreed territories as well as the clinical development for acquired antithrombin deficiency indications. GTC retained all rights to ATryn in all other territories.

GTC developed goats with the human antithrombin gene linked to a milk-protein promoter so that they express the antithrombin protein in their milk. This transgenic approach provides the opportunity to produce recombinant forms of proteins, such as anti-thrombin, which are difficult to express in conventional production methods.

GTC estimates, there are approximately 80,000 people in the European Union and 60,000 people in the US with HD (hereditary antithrombin deficiency).