GTC Biotherapeutics Reports Progress in ATryn Program in U.S.

Published: Mar 09, 2009

FRAMINGHAM, Mass.--(BUSINESS WIRE)--GTC Biotherapeutics, Inc. ("GTC", Nasdaq: GTCB) has received a $1 million milestone payment from OVATION Pharmaceuticals, Inc., the commercialization and development partner for ATryn® (Antithrombin [Recombinant]) in the United States. The milestone payment reflects the recommendation for approval by the Blood Products Advisory Committee meeting in January 2009. A total of $3 million of additional milestone payments from OVATION are pending as a result of the approval of ATryn by the Food and Drug Administration.

In addition to the payments for successful completion of the regulatory milestones, payment for $1 million of ATryn inventory is anticipated to support OVATION’s launch of the product in the second quarter. OVATION is doubling their sales team dedicated to hematology and they have established a dedicated medical sciences liaison team to support the launch of ATryn.

“We are pleased to build on the successful approval of ATryn to begin the commercialization and further development of the product in the US,” stated Geoffrey F. Cox, PhD, GTC’s Chairman and CEO. “OVATION, which was recently recognized as Frost & Sullivan’s 2009 entrepreneurial company of the year, is particularly well suited to bring the benefits of recombinant antithrombin to hereditary deficient patients who currently have limited options.”

OVATION and GTC are also collaborating on a joint development plan for ATryn as a supplement to restore heparin responsiveness in heparin resistant patients. Coronary artery bypass graft and related surgeries where a cardiopulmonary bypass machine, or CPB, is used require that patients are anticoagulated prior to going on bypass, in order to avoid clot formation. Heparin is used to prevent the formation of blood clots. Heparin’s ability to prevent clotting depends on the presence of sufficient antithrombin in the bloodstream to achieve the desired anticoagulant effect. It is estimated that over 20 percent of patients in CPB related surgeries exhibit heparin resistance. GTC has previously conducted studies related to this indication and one or more additional clinical trials may be required to obtain FDA approval. The anticipated phase III clinical study is projected to begin in 2009.

Important Safety Information

ATryn® (Antithrombin [Recombinant]) was approved on February 6, 2009 for the prevention of peri-operative and peri-partum thromboembolic events in hereditary antithrombin deficient patients. ATryn is contraindicated in patients with known hypersensitivity to goat and goat milk proteins. Allergic-type hypersensitivity reactions, including anaphylaxis are possible. If these reactions occur during administration, treatment must be discontinued immediately and emergency treatment should be administered.

The anticoagulant effect of drugs that use antithrombin to exert their anticoagulation may be altered when ATryn is added or withdrawn. To avoid excessive or insufficient anticoagulation, coagulation tests suitable for the anticoagulant used (e.g., aPTT and anti-Factor Xa activity) are to be performed regularly, at close intervals, and in particular in the first hours following the start or withdrawal of ATryn. Additionally, patients must be monitored for the occurrence of bleeding or thrombosis in such situations.

The serious adverse reaction that has been reported in clinical studies is hemorrhage (intra-abdominal, hemarthrosis and post procedural). The most common adverse events reported in clinical trials at a frequency of >= 5% are hemorrhage and infusion site reaction.

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About GTC Biotherapeutics

GTC Biotherapeutics develops, supplies, and commercializes therapeutic proteins produced through transgenic animal technology. ATryn®, GTC’s recombinant human antithrombin, has been approved for use in the United States and Europe. ATryn is the first and only transgenically produced product to be approved for therapeutic use anywhere in the world. In addition to ATryn, GTC is developing a portfolio of recombinant human plasma proteins with known therapeutic properties. These proteins include recombinant forms of human coagulation factors VIIa, VIII, and IX, which are being developed for the treatment of hemophilia, and alpha-1 antitrypsin. GTC is developing a monoclonal antibody to CD20 with enhanced ADCC (antibody-dependent cell-mediated cytotoxicity), and a proprietary monoclonal antibody to CD137 with potential indications in oncology and autoimmune disease. GTC is also developing a portfolio of follow-on biologic monoclonal antibodies. GTC’s intellectual property includes a patent in the United States through 2021 for the production of any therapeutic protein in the milk of any transgenic mammal. GTC’s transgenic production platform is particularly well suited to enabling cost effective development of proteins that are difficult to express in traditional recombinant production systems as well as proteins that are required in large volumes. Additional information is available on the GTC web site,

This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995, including without limitation statements regarding the anticipated further milestone and product inventory payments from OVATION and plans for commercial launch and further development of ATryn. Such forward-looking statements are subject to a number of risks, uncertainties and other factors that could cause actual results to differ materially from future results expressed or implied by such statements. Factors that may cause such differences include, but are not limited to, the risks and uncertainties discussed in GTC's most recent Annual Report on Form 10-K and its other periodic reports filed with the Securities and Exchange Commission, including the risks and uncertainties associated with dependence upon the actions of collaboration partners and regulatory agencies. GTC cautions investors not to place undue reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this document, and GTC undertakes no obligation to update or revise the statements, except as may be required by law.

Contact: GTC Biotherapeutics, Inc. Thomas E. Newberry, 508-370-5374 Vice President, Corporate Communications & Government Relations

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