FDA warns over heart risk of Multaq

The US Food and Drug Administration (FDA) is adding new safety warnings to the label of Sanofi's anti-arrythmic drug Multaq in light of data showing that it increases the risk of serious cardiovascular events, including death, in patients with permanent atrial fibrillation.

The agency started a safety review of Multaq (dronedarone) in July 2011, after Sanofi discontinued the PALLAS trial of the drug in permanent AF patients which revealed the safety issue.

The review has concluded that Multaq should only be given to AF patients who can be converted into normal sinus rhythm "because Multaq doubles the rate of cardiovascular death, stroke, and heart failure in such patients", according to an FDA announcement.

Doctors should also monitor the heart rhythm of patients taking dronedarone via an electrocardiogram (ECG) at least once every three months and, if the patient is in AF, Multaq should be discontinued, it says. Patients on dronedarone should also be on appropriate antithrombotic therapy.

The FDA's decision follows a similar verdict by the European Medicines Agency (EMA), which said in September that Multaq should only be prescribed for maintaining heart rhythm in patients with paroxysmal or persistent AF for the maintenance of sinus rhythm after successful cardioversion.

Even then, the drug should only be prescribed after alternative treatment options have been considered, the EMA concluded.

Multaq was approved in the US and Europe in 2009 and at the time was hailed as a potential blockbuster. Since then concerns about its safety - including the addition of a liver warning to its US labelling in January 2011 - have progressively trimmed back sales expectations.

Sales of the drug reached €197m in the first nine months of 2011, a rise of 88 per cent over the same period of 2010. Despite the restricted labelling, analysts believe the drug will continue to play a role in treating a subpopulation of AF patients, perhaps topping $500m in sales at peak.

The FDA says it is still reviewing a risk evaluation and mitigation strategy (REMS) for Multaq and will determine what changes may be necessary to ensure that the benefits of the drug outweigh the risks of cardiovascular death, stroke and heart failure.