Heart Risks With Multaq Being Reviewed in U.S. and Canada

Drug regulators in the United States and Canada have launched a review of the potential heart risks of Multaq, a relatively new drug sold by Sanofi-Aventis for treatment of abnormal heart rhythms. The review was launched after the drug maker decided to cancel certain clinical trials because the medication was deemed too risky for some heart patients. 

On Thursday, the FDA released a drug safety communication announcing a review of the potential side effects of Multaq for people with certain kinds of heart problems who could be at increased risk of cardiovascular events.

Health Canada made a similar announcement this week, and the European Union announced earlier this month that they were also conducting a review.

The heart concerns with Multaq first surfaced after Sanofi announced on July 7th that it was discontinuing a study on the use of the drug to treat permanent atrial fibrillation, a form of abnormal heart rhythm. The study was canceled after researchers identified a significant increase in the number of cardiovascular events suffered by participants in the group given Multaq. Similar increases were not seen among those given a placebo.

The study, known as PALLAS, was deemed too dangerous to those enrolled and two committees overseeing the safety of the study decided it would have been unethical to continue. More than 3,000 participants, all 65 years of age or older, were told to discontinue use of the drug for the treatment of permanent atrial fibrillation. Multaq is already approved to treat non-permanent atrial fibrillation.

“A critical question is whether and how the unfavorable results of the PALLAS study, obtained in patients with permanent atrial fibrillation, apply to patients who use Multaq for the approved indications,” the FDA stated in their announcement this week.

The FDA said it will take a close look at the data from the PALLAS study, but released some preliminary numbers which led to the study’s shutdown. As of June 30, there were 16 deaths involving patients given Multaq, compared to seven among those given a placebo. Multaq users also suffered 17 strokes, compared to seven among the control group, and there were 34 subjects taking Multaq who were hospitalized due to heart failure, while only 15 had to be hospitalized for heart failure among the group given placebos.

The FDA has not reached a conclusion about the Multaq heart risks, but is currently warning doctors not to give the drug to patients with permanent atrial fibrillation. 

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 liver damage from Multaq, 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.