Study treatments for the ACTIVE W trial of the ACTIVE ( Atrial Fibrillation Clopidogrel Trial with Irbesartan for Prevention of Vascular Events ) program have been discontinued due to a significant difference in efficacy, in favour of the standard oral anticoagulation ( Warfarin ) over antiplatelet therapy ( Clopidogrel plus Aspirin ).

The ACTIVE trial, the largest randomised international trial program ever conducted in atrial fibrillation, was designed to respond to a largely unmet medical need in the treatment of patients with atrial fibrillation, who are at an increased risk of life-threatening vascular events such as stroke, myocardial infarction and death.

Investigators at 600 sites will adjust their patients' medications and continue to monitor their health. Approximately 3,000 patients worldwide will be affected by the changes in the study.

After an interim analysis of the study, the recommendation of an independent Data Safety Monitoring Board to discontinue the ACTIVE W trial was endorsed by the ACTIVE study steering committee.

The board also recommended two other trials of the ACTIVE program be continued.

The study's steering committee agreed with the recommendation to discontinue study treatments for ACTIVE W, and endorsed the recommendation to continue the ACTIVE A ( Clopidogrel compared with ASA alone ), and ACTIVE I ( Irbesartan to placebo in addition to usual blood pressure lowering therapy ).

" In the ACTIVE W trial, most of the patients had been receiving oral anticoagulation prior to entry into the trial," said SalimYusuf, chairman of the steering committee for the ACTIVE trial program. " These patients achieved high levels of compliance to oral anticoagulation in the recommended therapeutic range. In the ACTIVE-W trial, a clear benefit in favour of oral anticoagulation was evident."

Stuart Connolly, principal investigator of the program, emphasized that: " It is important to continue the ACTIVE A and ACTIVE I parts of the study program to evaluate the potential role which Clopidogrel ( Plavix ) can play in the management of atrial fibrillation patients who are intolerant to oral anticoagulants, and to understand the role of Irbesartan ( Avapro ) in patients with atrial fibrillation."

Clinical guidelines recommend the use of oral anticoagulation therapy for most patients with atrial fibrillation in order to prevent embolic events.
However, oral anticoagulation therapy is associated with a narrow therapeutic window, requires regular monitoring and is contraindicated in some patients.
Aspirin is an option in patients who cannot tolerate oral anticoagulations.

The ACTIVE W trial was designed to investigate whether dual antiplatelet therapy could prevent embolic events in atrial fibrillation, an alternative to oral anticoagulant drugs such as Warfarin.

Source: McMaster University, 2005


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