Merck Drops New Heart Drug Following Multaq Problems

Concerns over potential side effects similar to those encountered with the Sanofi-Aventis heart drug Multaq may have contributed to Merck & Co.’s decision to drop development of a similar heart drug, Vernakalant. 

Merck announced last week that it was discontinuing involvement with an oral formulation of Vernakalant, without providing an explanation.

The company has been in a licensing agreement with a Canadian drug company, Cardiome Pharma, to develop the atrial fibrillation treatment as both an oral and intravenous treatment. The development of the intravenous version of the drug continues.

The announcement sent the much smaller Cardiome’s stock into freefall. Whlile Cardiome’s intravenous version of vernakalant is already available in Europe, Merck is looking to help the company introduce the medication into the U.S. market.

The announcement has led to speculation that recent problems with Multaq, another atrial fibrillation drug that is already available in the United States, may have contributed to Merck’s decision to back away from an atrial fibrillation treatment pill.

Multaq (dronedarone) was approved in July 2009 for the treatment of patients who have had abnormal heart rhythms in the last six months. Over the past year, side effects of Multaq have been linked to a possible risk of liver failure, liver damage, heart attacks, strokes, heart failure and death.

In January 2011, the FDA required new warnings about the potential risk of liver failure or liver injury from Multaq, indicating that at least two patients on Multaq suffered acute liver failure that required them to get a liver transplant.

In December, the FDA issued another Multaq safety warning, advising that the drug should not be used in patients whose abnormal heart rhythms were permanent. The agency indicated at that time that it was weighing recent findings to determine whether the risk of Multaq side effects in all patients outweigh the drug’s benefits. If that is the case, the FDA could issue a Multaq recall.

The FDA announcement followed an examination of data from a clinical trial known as PALLAS, which was a test by the manufacturer to see if Multaq could be used to treat permanent and recurring heart rhythm problems. However, the PALLAS trials were cancelled this summer due to an alarming number of heart attacks, strokes and deaths experienced by users, which has raised concerns over the possibility of Multaq heart problems.