GTC's lead product, ATryn, a recombinant form of human antithrombin, also known as ATIII, is at the forefront of transgenic technology for the production of biotherapeutics. Antithrombin is a plasma protein with anticoagulant and anti-inflammatory properties that, like many other therapeutic proteins which are currently derived from the human blood supply, has been difficult to express using conventional recombinant protein production methods.

In the United States the Food and Drug Administration (FDA) approved ATryn for the prevention of peri-operative and peri-partum thromboembolic events in hereditary antithrombin deficient, or HD, patients. ATryn is the first ever transgenically produced therapeutic protein and the first recombinant antithrombin approved in the U.S. Atryn is now available for sale in the United States.

In August of 2006, following a positive opinion by the CHMP, the European Commission approved ATryn under exceptional circumstances for the prophylaxis of venous thromboembolism in surgery of patients with congenital antithrombin deficiency.

October 27, 2010 - GTC Biotherapeutics Reports Third Quarter 2010 Financial Results

July 27, 2010 - GTC Biotherapeutics Reports Second Quarter 2010 Financial Results

July 16, 2010 - GTC Biotherapeutics Regains US Rights to ATryn ; the First Recombinant Antithrombin Product Approved in the World

May 12, 2010 - GTC Biotherapeutics Reports First Quarter 2010 Financial Results

April 13, 2010 - GTC Enters Atryn Registration License with Bio Sidus Argentina

March 12, 2010 - GTC Biotherapeutics Reports Fourth Quarter and Fiscal Year End 2009 Financial Results

November 6, 2009 - GTC Biotherapeutics Reports Third Quarter 2009 Financial Results

July 16, 2009 - GTC Biotherapeutics PRESS RELEASE - Data Show ATryn Effectively Prevents Serious Blood Clots

May 6, 2009 - GTC Biotherapeutics Reports Launch of ATryn in the U.S. by GTC Biotherapeutics Inc.

May 6, 2009 - ATryn Available for Patients with Hereditary Antithrombin Deficiency, a Rare Blood Clotting Disorder

March 30, 2009 - GTC Biotherapeutics Reports Progress in Preparations to Launch ATryn in the U.S.

March 9, 2009 - GTC Biotherapeutics Reports Progress in ATryn Program in U.S.

February 27, 2009 - GTC Biotherapeutics Reports Fourth Quarter and Year End 2008 Financial Results

February 6, 2009 - ATryn (Antithrombin [Recombinant]) Approved by the FDA - Only recombinant option for patients with hereditary antithrombin deficiency, a rare and potentially life-threatening condition

January 9, 2009 - FDA Advisory Committee Recommends GTC Biotherapeutics' ATryn* (antithrombin [Recombinant]) -
If approved, ATryn will be first recombinant human antithrombin available in the U.S.¹

November 3, 2008 - GTC Biotherapeutics Reports Third Quarter 2008 Financial Results

October 6, 2008 - FDA Accepts ATryn BLA Filing - GTC Receives $2 Million in Additional Milestone Payments

September 4, 2008 - FDA Assigns Priority Review to GTC BiotherapeuticsATryn

August 14, 2008 - GTC Biotherapeutics and Ovation Pharmaceuticals Close Agreement to Market and Develop ATryn in the U.S.

August 7, 2008 - GTC Biotherapeutics Completes BLA Submission for Atryn

August 7, 2008 - GTC Biotherapeutics Reports Second Quarter 2008 Financial Results

June 23, 2008 - GTC Biotherapeutics Enters into $257 Million Agreement with OVATION Pharmaceuticals to Develop and Market ATryn in the U.S.

May 8, 2008 - GTC Biotherapeutics Reports First Quarter 2008 Financial Results

February 4, 2008 - ATryn Meets Primary Endpoint/Rolling BLA Submission Initiated

January 7, 2008 - ATryn Nears Completion of US HD Clinical Study