GTC Biotherapeutics and Scancell Collaborate on SC101 Antibody

FRAMINGHAM, MA and NOTTINGHAM, UK – July 28, 2005 -- GTC Biotherapeutics, Inc. ("GTC", Nasdaq: GTCB) and Scancell Limited (“Scancell”) announced that they have signed a collaboration agreement to evaluate the expression of Scancell’s SC101 anti-cancer monoclonal antibody (MAb) using GTC’s transgenic production platform. Their agreement contemplates that both companies will work toward the establishment of a definitive agreement for the potential clinical development of SC101.

“We look forward to demonstrating the value offered by transgenic technology for the production of antibody products such as SC101,” noted Gregory Liposky, GTC’s Senior Vice President, Operations. “GTC’s technology offers significant advantages for the development of proteins that are projected to be required in large commercial production quantities, when approved, and we believe we can assist Scancell in realizing that potential value.”

Commenting on the agreement, Michael Capaldi, Chief Executive Officer of Scancell, said: "We are very pleased to be working with GTC. This agreement offers Scancell the opportunity to establish development of what we believe will be a very large scale product at significantly lower capital investment."

SC101 is a MAb that targets Lewisy/b. Lewisy/b is a cell surface carbohydrate blood group antigen whose xpression is very low in normal tissue but is over-expressed on breast, colorectal, endometrial, kidney, lung, pancreas and stomach tumours. Mouse antibodies recognizing Lewisy/b have induced tumor cell death and inhibited growth of various tumor lines. In animal studies, tumor growth was inhibited by anti-Lewisy/b antibodies alone, and especially when combined with 5-fluorouracil, an antimetabolite that disrupts cancer cell growth.

About GTC Biotherapeutics

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 ATryn®, its recombinant form of human antithrombin. A Market Authorization Application is under review by the European Medicines Agency for the use of ATryn® in patients with a hereditary antithrombin deficiency. In addition to the ATryn® 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,

This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995, including statements regarding the prospects for anticipated expression of SC101 in a transgenic production system and for a definitive agreement with Scancell for further development of transgenic production for SC101. 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 risks and uncertainties inherent in the development of transgenic expression of compounds and the actions of collaboration partners. 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. GTC specifically disclaims responsibility for information describing Scancell, its business and SC101, other than the collaboration with GTC.

About Scancell

Scancell Ltd is a company focused on the discovery and development of products that harness the immune system in a unique way to treat or prevent cancer. The Company, which currently employs 12 individuals, has secured £4.6million of private equity and commercial funding. The Company has built an early stage product pipeline based upon two platforms: directly killing MAbs (‘killer’ MAbs) and its patent protected ImmunoBody® vaccine platform. ‘Killer’ MAbs are raised against ‘cocktails’ of primary human tumours resulting in MAbs that recognize clinically relevant targets. The Company screens for MAbs that directly kill tumour cells (i.e. without the need for antibody-dependant cellular cytotoxicity (ADCC) or complement mediated cytotoxicity (CDC)) and have an additive and/or synergistic killing effect in the presence of chemotherapeutics. Scancell has three such products in pre-clinical development and a number of further ‘killer’ MAbs in research. Scancell’s ImmunoBody® technology uses human antibodies as vectors to target clinically relevant T-cell epitopes to activated dendritic cells via the high affinity CD64 receptor thereby initiating cellular immunity against cancers or chronic infectious diseases. For more information about Scancell visit

Except for the historical information presented herein, matters discussed in this press release are forward-looking statements that are subject to certain risks and uncertainties that could cause actual results to differ materially from any future results, performance or achievements expressed or implied by such statements, e.g. unforeseen exchange rate and interest rate fluctuations, delayed or unsuccessful development projects.

Statements that are not historical facts, including statements preceded by, followed by, or that include the words "believes"; "anticipates"; "plans"; "expects"; "estimates"; or similar statements are forward-looking statements. Scancell is not under an obligation to up-date statements regarding the future following the publication of this release; nor to confirm such statements in relation to actual results, unless this is required by law.