FDA clears GTC's ATryn, first US-approved drug made from a transgenic animal

USA-based drug developer GTC Biotherapeutics' human antithrombin ATryn has been approved by the Food and Drug Administration for the prevention  and treatment of venous thromboembolism in hereditary  antithrombin-deficient patients undergoing surgery or childbirth.

Framingham, Massachusetts-based GTC predicts Atryn could earn as much as  $50.0 million in annual US sales in its first five years on the market.  On the day the agent was approved, January 6, shares in the firm rose  just 1% to  $0.83 cents in early afternoon trading.

Hereditary antithrombin deficiency is estimated to affect one in 2,000  to one in 5,000 people, half of whom may experience a thrombosis before  reaching 25 years of age and, based on a study, up to 85% may suffer a  thromboembolic event by age 50.