At the European Society of Cardiology (ESC) congress in August 2009, researchers reported that a potential thrombin inhibitor, dabigatran etexilate, was more effective than warfarin in reducing strokes and embolism events in people with atrial fibrillation (AF) – a form of irregular heartbeat. The NEJM also released a simultaneous online report of this new trial.
The authors said that warfarin treatment needs regular monitoring because it can cause bleeding and other complications and argued that there is a need for a new anticoagulant drugs that are safe, effective and convenient to use. Dabigatran is already licensed for use in people having hip and knee replacement surgery.
The study, known as the RE-LY trial, the Randomized Evaluation of Long-term Anticoagulation Therapy, recruited over 18,000 people with AF, average age of 71, from 44 countries and 951 centres, who had at least one other risk factor for stroke. People with severe heart valve disorder, condition that increased the risk of bleeding, liver disease, poor kidney or pregnant women were excluded.
Participants were randomly assigned to receive either 110 mg or 150 mg of dabigatran twice a day or warfarin treatment. Participants receiving dabigatran were blinded to what they were taking but those received warfarin were not. Participants were followed up for an average of 2 years.
The researchers found that those who took dabigatran reduced their risk of stroke and systemic embolism by 34%, also reduced risk of bleeding than warfarin. They concluded that the lower dose of dabigatran was as effective as warfarin for preventing stroke and embolism events, the higher dose was more effective than warfarin for preventing these events and there was no need for regular monitoring .
Critics noted that the higher dose of dabigatran was associated with higher risk of heart attack and had more gastric symptoms when compared to warfarin. More patients discontinued taking dabigatran than those with warfarin after 1 and 2 years of follow up due to serious adverse events. They also cautioned that the design that patients and physicians knew of the treatment allocation can bias the outcomes and that long term outcomes should be explored before the drug is licensed for people with AF.
In an accompanying editorial, the author said that dabigatran had greater risk of nonhemorrhagic side effects, “patients already taking warfarin with excellent INR control have little to gain by switching to dabigatran”, however other patients who have AF and at least one additional risk factor for stroke could benefit from it.
The study was funded by Boehringer Ingelheim, the manufacture of dabigatran. All outcome events were assessed by 2 independent investigators who were blinded to the treatment assigned to the participants.
Source: Connolly SJ, Ezekowitz MD, Yusuf S et al. "Dabigatran versus Warfarin in Patients with Atrial Fibrillation". NEJM 2009; 361(12):1139-1151
Online editorial - Gage B. "Can We Rely on RE-LY?". NEJM August 30, 2009
No comments:
Post a Comment