Arixtra for acute coronary syndrome

The FDA is expected to make a decision on February 2, 2007 whether to approve a new indication for Arixtra (fondaparinux). Fondaparinux is an injectable drug manufactured by GlaxoSmithKline, which is currently indicated for treatment of pulmonary embolism (PE) and distal venous thromboembolism (DVT) with or without warfarin. Fondaparinux is also approved for prevention of DVT and PE in patients undergoing various surgeries such as hip and knee replacements, hip fracture repair, and abdominal surgery. The new indication will be for the treatment of acute coronary syndrome. If Fondaparinux is approved for this indication, it may compete with LMWHs such as Lovenox (enoxaparin) an anticoagulant also being used for acute coronary syndrome. Enoxaparin is approved for prevention of DVT in patients undergoing hip or knee replacement surgery, abdominal surgery, treatment of myocardial infarction, acute PE, and also (DVT) when combined with warfarin.

Fondaparinux and enoxaparin work through different mechanisms to promote anticoagulation. Enoxaparin is a low molecular weight heparin that enhances antithrombin III activity, which in turn inhibits coagulation factor Xa and also factor IIa to a lesser extent. Fondaparinux still affects antithrombin III by enhancing antithrombin III’s inhibition of coagulation factor Xa. Both mechanisms result in anticoagulation, however fondaparinux does not precipitate inhibition of coagulation factor IIa.

References:

1. Perrone M. (2007, January 31). New use expected for Glaxo drug. Business Week. Retrieved 31 January, 2007, from http://www.businessweek.com/ap/financialnews/D8N0DP4G0.htm
2. Clinical Pharmacology [Internet Database]. c2006-[updated 2007 January; cited 2007 31 January]. Available from: http://cpip.gsm.com

Prepared by: Sarah Workman, PharmD. Candidate