GTC Biotherapeutics, Inc. announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMEA) has adopted a positive opinion on the market authorization application (MAA) for ATryn, GTC's recombinant form of human antithrombin.

The CHMP has recommended that ATryn be granted market authorization for the prophylaxis of venous thromboembolism in surgery of patients with congenital antithrombin deficiency. ATryn may be given in association with heparin or low molecular weight heparin in these situations. The CHMP opinion recommends granting market authorization under the EMEA's procedures for exceptional circumstances. Final market authorization by the European Commission is expected in about three months. The positive CHMP opinion followed a defined process this week that included a review of GTC's submission of the grounds supporting re-examination of the previous opinion as well as a review of responses to specific questions posed by the CHMP to an independent expert panel composed of internationally recognized experts in the fields of haematology and haemostasis. These review activities are an integral part of the regulatory process for re-examination of a prior opinion.

Upon approval, ATryn will be the first antithrombin product approved for use in all 25 countries of the European Union. ATryn will also be the only available antithrombin product that is produced by recombinant biotechnology and is not derived from the human blood supply.

Professor Isobel Walker, Consultant Haematologist, Glasgow Royal Infirmary, comments that, "It is a good day for European patients with congenital antithrombin deficiency and for their physicians. ATryn provides an alternative to treatment with human plasma derived antithrombin and gives physicians and patients more choice in how they will be treated."

"Today's announcement marks a very significant achievement for GTC, being the first company to obtain a positive regulatory opinion on the commercial use of a therapeutic protein that is produced transgenically," stated Geoffrey F. Cox, Ph.D., GTC's Chairman of the Board and Chief Executive Officer. "ATryn presents an opportunity for hereditary deficiency patients in Europe to choose an antithrombin product that has met the rigorous examination and review requirements of the centralized EMEA procedures for recombinant proteins. The dedication and perseverance of our employees have been instrumental in GTC reaching this point. We look forward to working with our European partner, LEO Pharma A/S, to begin the activities required to launch this product in the marketplace and to support the further development of ATryn for the treatment of DIC associated with severe sepsis. The positive opinion is also very supportive of the continuing development of ATryn in our ongoing study of the hereditary deficiency indication for a regulatory submission in the United States. This opinion marks an important step in our strategy to advance the significant commercial opportunity which we believe ATryn offers and to unlock the value of our transgenic technology for the production of therapeutic proteins."

GTC anticipates using the results from both the completed study reviewed by the CHMP and GTC's ongoing pivotal phase III study to prepare a Biologics License Application for the United States Food and Drug Administration. The results of the pivotal phase III study will also be submitted for consideration by the CHMP for expansion of the use of ATryn in Europe to prevent deep vein thromboses and thromboembolisms in women with a hereditary antithrombin deficiency who are undergoing childbirth.

Antithrombin is a protein in human plasma that has anticoagulant and anti-inflammatory properties. LEO Pharma has also begun development of ATryn in Europe as a potential treatment for disseminated intravascular coagulation, or DIC, associated with severe sepsis. DIC occurs in an estimated 220,000 severe sepsis cases in the European Union each year, of which approximately 50 per cent are fatal, representing a major unmet medical need of significant interest in critical care.