DATA PRESENTED BY THE UNIVERSITY OF TEXAS MEDICAL BRANCH AND SHRINERS HOSPITAL FOR CHILDREN AT THE AMERICAN BURN ASSOCIATION'S 35th ANNUAL MEETING
FRAMINGHAM, MA - April 2, 2003 -- GTC Biotherapeutics, Inc. ("GTC", Nasdaq: GTCB) today announced that the University of Texas Medical Branch at Galveston (UTMB) and Shriners Hospital for Children, Galveston, presented results of a preclinical study on the use of GTC's recombinant human antithrombin III (rhATIII) to treat acute lung injury from smoke inhalation and pneumonia. The results were presented at the 35th Annual Meeting of the American Burn Association, being held April 1 to April 4 in Miami. Highlights of the presentation included data regarding the inhibition of airway obstruction and impaired gas exchange in the lungs of sheep when treated with rhATIII. "Airway obstruction is a very serious clinical problem," said Dr. Daniel L. Traber, Charles Robert Allen Professor of Anesthesiology at the University of Texas Medical Branch at Galveston, senior researcher of the study. Dr. Traber continued, "The obstruction not only makes it impossible to ventilate the portions of the lung below the block but it also results in over inflation of non-obstructed lung. This latter over inflation has been shown to seriously permanently damage the lung. Antithrombin III appears to help prevent the formation of the materials responsible for the obstruction through its anti-inflammatory action and to prevent the solidification of the airway materials by blocking the clotting mechanisms. We have shown in this preclinical model that by delivering antithrombin into the airway we also prevent any changes in systemic clotting mechanisms so that there are little or no problems with bleeding." The presentation described the results of an evaluation of rhATIII as an anticoagulant and anti-inflammatory agent in treating sheep who were subjected to smoke inhalation and subsequent pneumonia. Treatment with rhATIII provided higher pulmonary gas exchange ratios than saline, comparable to the results obtained with a commercially available synthetic direct thrombin inhibitor. The rhATIII treatments resulted in lower levels of nitrous oxides in the sheep's plasma and improved mean arterial pressures compared with either the saline or the commercially available synthetic direct thrombin inhibitor treatments. These results suggest that rhATIII may have promise as a safe and effective treatment for acute lung injury following smoke inhalation and pneumonia. GTC is also making significant progress in bringing its lead rhATIII program through advanced clinical studies in patients with a hereditary antithrombin deficiency (HD). A PK study in 15 HD patients in Europe was successfully completed, establishing the dosing protocol for an efficacy study. GTC has begun an efficacy study of HD patients that is expected to be the final study before filing for market authorization in Europe. The efficacy study is evaluating the incidence of deep vein thrombosis in HD patients that are undergoing surgery or childbirth. The efficacy study is expected to include at least 12 patients and is continuing to make progress toward completion before the end of 2003. GTC expects to file for European market authorization in the first half of 2004. If approved, rhATIII is expected to be the first transgenically derived product to be approved in Europe. GTC expects to define the US regulatory strategy for rhATIII during 2003. Antithrombin is a human blood protein that has anticoagulant and anti-inflammatory properties. The antithrombin blood protein is difficult to express in traditional bioreactor based production systems. Plasma derived antithrombin product has about $250 million in worldwide sales for a variety of indications, including $10 million in the US for the HD indication. GTC believes that its recombinant form will allow for a more highly characterized product with a stable source of supply that has the potential to expand the market through additional indications based on well-designed clinical studies. GTC believes that rhATIII has potential to be developed as a treatment for burns. This would enable the Company to participate in the worldwide burns market that GTC estimates to be $300 million to $500 million. GTC is seeking a corporate partner for the rhATIII program to support the significant further development required in the burns indication. The title of the presentation at the 35th Annual American Burn Association Meeting was "Aerosolized recombinant antithrombin attenuates ovine acute lung injury with smoke inhalation and pneumonia." GTC and UTMB have concluded an agreement that will enable further development of the treatment of burns using rhATIII. GTC Biotherapeutics is the leader in the development, production, and commercialization of therapeutic proteins through transgenic animal technology. GTC has more than a dozen programs in development and one product in clinical trials. These programs are focused on developing both large-volume protein therapeutics as well as products that are difficult to produce in significant quantities from conventional bioreactor systems. In addition to the rhATIII program, GTC is developing a recombinant human serum albumin and a malaria vaccine. GTC's external program collaborations are developing transgenic versions of products such as monoclonal antibodies and immunoglobulin fusion proteins for conditions such as rheumatoid arthritis, HIV/AIDS and cancer. These external partners include Abbott, Bristol-Myers Squibb, Centocor, Elan, Alexion, ImmunoGen, Merrimack and Progenics. Additional information is available on the GTC web site, http://www.gtc-bio.com. This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995, including without limitation statements regarding GTC's prospects for successful completion of its ongoing efficacy study and filing for marketing approval of rhATIII in Europe, its ability to successfully develop a US regulatory strategy for rhATIII, and its prospects for developing rhATIII as a potential treatment for burns. 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 the Company's most recent Annual Report on Form 10-K and its other periodic reports as filed with the Securities and Exchange Commission, including the risks and uncertainties associated with clinical studies, difficulties in obtaining additional partners, and dependence upon the actions of regulatory agencies. The Company 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 the Company undertakes no obligation to update or revise the statements, except as may be required by law. CONTACT:GTC Biotherapeutics
Thomas E. Newberry
Vice President, Corporate Communications
(508) 270-2374 Burns McClellan, Inc. for GTC
Jonathan M. Nugent (investors)
Kathy Jones, Ph.D. (media)
(212) 213-0006
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