Sanofi has reaffirmed its confidence in the benefits of Multaq as the US Food and Drug Administration followed its European counterparts by launching a safety review of the anti-arrhythmic.

Earlier this month, the French drugmaker discontinued the PALLAS trial in patients with permanent atrial fibrillation, different from the population with non-permanent AF for which Multaq (dronedarone) is currently approved. A significant increase in cardiovascular events was seen in the dronedarone arm", so the study was pulled.

The FDA says it is now reviewing the data, noting that "a critical question is whether and how the unfavourable results of the PALLAS study, obtained in patients with permanent AF, apply to patients who use Multaq for the approved indications (non-permanent AF)". The agency previously issued a drug safety communication in January 2011 regarding cases of rare but severe liver injury reported with the use of Multaq.

The FDA move echoes the review being undertaken by the European Medicines Agency’s Committee for Medicinal Products for Human Use. The scope of that probe was extended to include the new information from the PALLAS study and further advice will be issued in September 2011.

Sanofi told PharmaTimes World News that it is working with the EMA and the FDA to provide the agencies with a full analysis of the data from PALLAS. The firm notes that some 400,000 patients have been treated with Multaq worldwide and considers that its benefit-risk profile "remains positive in its approved indication".