Tuesday, September 01, 2009

Closer and closer to a new oral anticoagulant (dabigatran)

Actually, there already is a new oral anticoagulant available in Europe and Canada at least for the application of clot prophylaxis in hip and knee surgery patients.Dabigatran is an oral direct thrombin inhibitor that is taken twice a day and requires no blood test monitoring .In Canada, the trade name is Pradax and in Europe,Pradaxa.


Data from the large RELY trial were presented in Barcelona in August 2009. Some details can be found here and the entire article is available on the NEJM web site for free.

18,000 patients with non-valvular atrial fibrillation were randomized into three groups:warfarin titrated to an INR of 2-3, dabigatran 110 mg twice a day and 150 mg twice a day.The lower dabigatran does was associated with a slightly lower rate of bleeding while the higher dose and warfarin had similar rates. With a median followup of 2 years there was no increase in abnormal liver function tests in either dabigatran group.

Liver function test is an important issue as an earlier another oral thrombin inhibitor (ximelagatran) was withdrawn from the market after it had been approved in several European countries because of liver problems.

One possible bump in the road to FDA approval is the finding of a small increase in heart attacks in both dabigatran groups. I can't guess how an anticoagulant could cause an increase in heart attacks but perhaps warfarin is better at reducing risk of myocardial infarctions. Even so, with the battles and bad press that the FDA has had in recent years with real or purported increase risk of myocardial infarctions with certain prescription drugs an anticipated 2010 approval might be overly optimistic.

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