The European Society of Cardiology is aware that Sanofi Aventis has discontinued its phase IIIb PALLAS trial, which evaluated dronedarone vs placebo in patients with permanent atrial fibrillation and at least one other cardiovascular factor (a population different from the population with non-permanent AF for which dronedarone is currently
approved).
The decision was taken as a significant increase in cardiovascular events in the dronedarone arm was observed.
Sanofi has informed regulatory authorities of this decision and the European Medicines Agency (EMA) is reviewing the overall benefit/risk profile of dronedarone.
The ESC is studying the new data available. Patients currently taking dronedarone should not stop their therapy and should consult their treating physician should they have any questions.
EMA Press Release (11 July 2011)
Sanofi Press Release (7 July 2011) 
Statement by the US Food and Drug Administration (FDA) (21 July 2011)
Our mission: To reduce the burden of cardiovascular disease.