FRAMINGHAM, MA - August 1, 2005 -- GTC Biotherapeutics, Inc. ("GTC", Nasdaq: GTCB) announced today that the United States Patent and Trademark Office has issued a notice of allowance for the claims in its patent application 10/635,117 covering tangential flow filtration technology. These claims provide GTC with a unique position in the use of this technology to recover recombinant therapeutic proteins that are expressed in the milk of transgenic animals. The patent that issues from this application will expire in 2023. Tangential flow filtration is an initial product recovery step that removes fats and other colloidal proteins such as casein from milk containing the target protein of interest. This approach also allows for the significant reduction in volume of the milk while yielding a material that can be aseptically processed. The resulting partially purified intermediate bulk product is more stable than unprocessed milk and can be stored for extended periods either refrigerated or frozen. The intermediate bulk product is then taken through additional purification steps, typically chromatography, to obtain a highly purified form of the desired therapeutic protein. GTC is able to produce a therapeutic protein in an animal's milk through a process known as transgenic technology. GTC couples the gene expressing a specific protein with a specific milk protein promoter gene and incorporates it into an animal's genome such that the protein is expressed during lactation. This approach has been demonstrated to enable the production of therapeutic proteins that are difficult to express in traditional production methods. For products that can be expressed in conventional recombinant technology, transgenic technology has significantly lower capital requirements to establish large volume capacity. About GTC Biotherapeutics, Inc.
GTC Biotherapeutics is a leader in the development, production, and commercialization of therapeutic proteins through transgenic animal technology. GTC currently has five products in its internal pipeline and a portfolio of external program production opportunities. GTC's lead program is ATrynŽ, its recombinant form of human antithrombin. A Market Authorization Application is under review by the European Medicines Agency for the use of ATrynŽ in patients with a hereditary antithrombin deficiency. In addition to the ATrynŽ program, GTC is developing a recombinant human alpha-1 antitrypsin, a recombinant human albumin, a malaria vaccine, and a CD137 antibody to stimulate the immune system as a potential treatment for solid tumors. In its external programs, GTC's technology is used to develop transgenic production of its partners' proprietary products, including both large-volume protein therapeutics as well as products that are difficult to produce in significant quantities from conventional recombinant production systems. One of the external programs is in clinical trials with a transgenically produced product. 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 patent position. 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 as filed with the Securities and Exchange Commission, including the uncertainties associated with intellectual property. 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
Vice President, Corporate Communications
(508) 370-5374 Feinstein Kean Healthcare for GTC Biotherapeutics, Inc.
Francesca DeVellis
(617) 577-8110
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