Sanofi-Synthelabo announces that it has reached agreement with NV Organon to acquire all of Organon interests relating to Arixtra (fondaparinux sodium), idraparinux and other oligosaccharides such as the hexadecasaccharide.

In addition to taking over ongoing development programs, Sanofi-Synthelabo will make payments to Organon based largely on future sales.

This agreement is in line with Sanofi-Synthelabo's strategy to gain full control of the worldwide rights relating to innovative products in its R&D portfolio. It further confirms Sanofi-Synthelabo's high level of confidence in the future success of synthetic oligosaccharides in very rapidly growing markets.

Arixtra, a selective synthetic factor Xa inhibitor, was launched in 2002 and 2003 in the United States and in some other major markets. Based on the largest ever clinical development program in this indication, Arixtra is approved for the short-term and extended prophylaxis of Venous Thromboembolism in patients undergoing major orthopaedic surgery.

In addition, Arixtra has now completed all planned studies in the prophylaxis and acute treatment of Venous Tromboembolism. Filing for the approval of the treatment indication was submitted to the FDA and the EMEA in July 2003.

Moreover, a very comprehensive phase III programme for the treatment of patients with Acute Coronary Syndrome is ongoing.

Idraparinux, a unique once a week synthetic pentasaccharide, is currently tested in phase III, against oral anticoagulant agents, in various indications including the prevention of vascular events associated with atrial fibrillation.

This acquisition is expected to be completed in the first quarter of 2004, subject to the receipt of approvals from competition authorities.