FRAMINGHAM, MA, May 8, 2007-GTC Biotherapeutics, Inc. ("GTC", Nasdaq: GTCB) announced today that Geoffrey Cox, Ph.D., GTC's Chairman and CEO, is scheduled to present on Monday, May 14, 2007 at 10:50 a.m. Central European Summer Time during the Acumen Biofin Rodman & Renshaw 4th Annual Global Healthcare Conference. The conference is being held at Le Meridien Beach Plaza Hotel, Monte Carlo, Monaco from May 14-15, 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. In August 2006, ATrynŽ, GTC's recombinant form of human antithrombin, was 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. Antithrombin is a protein with anticoagulant and anti-inflammatory properties. We have developed goats that have the human antithrombin gene linked to a milk-protein promoting gene so that they express this protein in their milk. This transgenic approach provides the opportunity to produce recombinant forms of proteins, such as antithrombin, that are difficult to express in economically viable quantities in conventional production systems. 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. The first program of the collaboration will be to develop recombinant human factor VIIa as a potential treatment for hemophilia in patients with antibodies to other coagulation factors.

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. Additional information is available on the GTC web site, http://www.gtc-bio.com.