GTC Biotherapeutics Inc. has been informed that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMEA) intends to issue a negative opinion on the market authorisation application (MAA) for ATryn, GTC's recombinant form of human antithrombin.

On the basis of recent conversations, GTC understands that the CHMP, after excluding data from pregnant patients, determined that an insufficient number of surgical patients were enrolled to support approval. In addition, GTC understands that the CHMP has concerns about sufficient immunologic data and the lack of clinical data from ATryn produced with an additional filtration step. GTC intends to take advantage of the appeal process to request a CHMP re-examination of GTC's submission, claims the company release.

GTC's European development and commercialisation partner, LEO Pharma A/S, has affirmed that they remain committed to their collaboration with GTC and will continue to pursue the primary goal of development of an acquired deficiency indication for Europe. Acquired deficiency indications represent the most significant market opportunity for the product. GTC and LEO entered into a collaborative development and commercialisation agreement for ATryn in Europe, Canada, and the Middle East in November 2005.

GTC is also continuing a multinational study of ATryn in hereditary antithrombin deficient patients in preparation for submission of a biologics license application (BLA) in the US. Enrolment is planned to be completed in 2006 and a BLA submitted in the first half of 2007.

GTC Biotherapeutics develops, produces, and commercialises therapeutic proteins through transgenic animal technology.