GTC Biotherapeutics, Inc. announced that its partner for ATryn in Europe, Canada and the Middle East, LEO Pharma A/S, has enrolled the first patient in a phase II study of the recombinant anti-thrombin product in the treatment of disseminated intravascular coagulation, or DIC, in association with severe sepsis.

Full enrolment of about 200 patients into the phase II study is planned to take approximately 12 months with results expected to be available in the second half of 2008, a GTC Biotherapeutics press release said.

Estimates from the scientific literature are that there are over 1.5 million cases of severe sepsis in the US and Europe and over 500,000 of these patients develop DIC, with a mortality rate of up to 50 per cent. A number of preclinical animal sepsis studies, as well as a human endotoxemia study, suggest that ATryn may have potential in the treatment of DIC associated with severe sepsis if provided without heparin, a critical care anticoagulant. A number of countries in Europe and Japan include the treatment of DIC associated with severe sepsis in the approved uses of plasma-derived anti-thrombin products.

In evaluating the clinical and commercial opportunities, GTC has determined that applying the cost of existing treatment options for severe sepsis to the estimated annual incidence of DIC indicates a total potential US market of $2-3 billion per year. The objective of the phase II study is to establish safety and to determine the optimum dose to be used in a subsequent phase III safety and efficacy study. LEO obtained Scientific Advice from the European Medicines Agency, or EMEA, on the design of the phase II study. GTC plans to use the phase II results as the basis of a discussion with the Food and Drug Administration on further clinical development of ATryn for the DIC indication in the US. GTC retains full commercial rights in the US, Japan, and the rest of the world outside the LEO territories.

ATryn is GTC's recombinant form of human anti-thrombin. Anti-thrombin, produced in the liver and circulated in blood plasma, has both anticoagulant and anti-inflammatory properties. The recombinant form is able to be produced using GTC's transgenic production platform, enabling large volume supply. ATryn has been approved for use in Europe for the prophylactic treatment of deep vein thrombosis in hereditary anti-thrombin deficient (HD) patients undergoing surgical procedures.

GTC is also nearing completion of the clinical studies necessary to support the filing of a Biologics License Application for ATryn in the HD indication planned for the first quarter of 2008. These studies include an evaluation of the incidence of deep vein thrombosis and thromboembolisms in 17 additional hereditary anti-thrombin deficient patients treated with ATryn during surgical and pregnancy procedures. A comparative historical study of approximately 35 patients treated with plasma derived anti-thrombin, and undergoing similar high risk procedures, is also nearing completion. GTC plans on releasing top line data from these studies in the fourth quarter of 2007. GTC is in discussions for potential commercial partnering for ATryn in the US market.