Multaq Heart Problems Too Dangerous for Clinical Trials

The potential side effects of Multaq, a Sanofi drug designed to treat heart problems, may have caused so many cardiovascular events that the company was recently forced to pull the plug on a study due to patient safety concerns. 

In a press release (pdf) issued on Thursday, Sanofi announced that it was discontinuing clinical trials to test Multaq’s effectiveness in treating patients with permanent atrial fibrillation, a form of abnormal heart rhythm. The drug is already approved to treat patients with a non-permanent form of the ailment. More than 3,000 patients enrolled in the study have been told to immediately stop taking Multaq.

The decision to stop the trials came after two committees overseeing the study, known as PALLAS, recommended the trials be halted after noting a significant increase in cardiovascular events among patients taking Multaq. Sanofi said it is informing regulatory agencies in all countries where Multaq is approved for use.

The company stressed in its release that the clinical trial population was very different from the population for which the drug has already been approved. About 70 percent of the patients in the study had been diagnosed with permanent atrial fibrillation that had lasted over two years. Previous studies included no patients with permanent atrial fibrillation, the company said.

Multaq (dronedarone) was approved in July 2009 for the treatment of patients who have had abnormal heart rhythms in the last six months. In less than two years since its approval, there have been at least 492,000 Multaq prescriptions in the United States filled by about 147,000 patients at outpatient pharmacies across the country. In addition, the drug can be given to patients being treated in hospitals.

In January, the FDA warned about the potential risk of Multaq liver side effects, indicating that two patients on Multaq suffered acute liver failure that required them to get liver transplant.

A couple weeks after that warning in the United States, the FDA also sent a letter to Sanofi Aventis, admonishing the company for failing to pass on three adverse event reports involving Multaq side effects to the government.

According to a quarterly report by the Institute for Safe Medication Practices published the same month, at least nine reported cases of serious liver damage or injury from Multaq were identified among adverse event reports submitted to the FDA during the second quarter of 2010.

Sanofi Aventis maintains in their press release that the cancellation of the clinical trials had nothing to do with Multaq liver problems.