GTC Biotherapeutics to Webcast Corporate Presentation at the BIO InvestorForum 2007.

FRAMINGHAM, Mass. -- GTC Biotherapeutics, Inc. ("GTC", Nasdaq: GTCB) announced today that Geoffrey Cox, Ph.D., GTC's Chairman and CEO, is scheduled to present on Wednesday, October 10, 2007 at 10:45 a.m. Pacific Time during the BIO InvestorForum 2007. The conference is being held at the Palace Hotel in San Francisco, California from October 9 - 11, 2007.

The presentation will be webcast live and can be accessed by logging onto www.gtc-bio.com. The replay can be accessed from this same website and will be available within 24 hours of the presentation.

About GTC Biotherapeutics

GTC Biotherapeutics develops, produces, and commercializes therapeutic proteins through transgenic animal technology. ATryn([R]), GTC's recombinant form of human antithrombin, is approved by the European Commission for use in patients with hereditary antithrombin deficiency undergoing surgical procedures. This was the first approval anywhere in the world of a therapeutic protein produced from a transgenic animal.

LEO Pharma A/S, ATryn([R])'s commercial and development partner in Europe, Canada, and the Middle East, is in the process of launching in the approved indication and recruiting patients into a Phase II dose ranging study for the treatment of disseminated intravascular coagulation associated with severe sepsis. GTC is conducting a Phase III study of ATryn([R])which was recently designated as a Fast Track Product by the FDA in the United States in hereditary antithrombin deficiency patients undergoing high risk surgical and childbirth procedures. In addition, GTC has established a strategic collaboration with LFB Biotechnologies of France to jointly develop recombinant forms of human plasma proteins and monoclonal antibodies.

In 2006, GTC was granted 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 those that are required in large volumes at a competitive cost. Additional information is available on the GTC web site, http://www.gtc-bio.com.