Sanofi to Send Letter on Multaq Liver Failure Cases

Sanofi-Aventis SA will send a letter to U.S. doctors telling them that two patients taking the Multaq heart treatment have suffered liver failure.

France’s biggest drugmaker will inform doctors about liver function test results and injuries reported in patients treated with Multaq, including two cases of acute liver failure, Jean-Marc Podvin, a company spokesman, said in a telephone interview today. A causal relationship hasn’t been established between Multaq and liver injury, he said.

Almost 200,000 patients worldwide have been prescribed Multaq since the drug was introduced, Podvin said. Sanofi is counting on sales of Multaq to help offset a loss of revenue as products including the blood-thinner Plavix and the cancer treatment Taxotere face generic competition. Revenue from Multaq may reach 838 million euros ($1.1 billion) by 2013, according to the average estimate of five analysts surveyed by Bloomberg.

“Multaq will be an important drug over the next 10 years” for Sanofi and the treatment “cannot afford to face serious side effects that are tough to resolve,” Eric Le Berrigaud, an analyst at Raymond James in Paris, who has a “buy” recommendation on Sanofi shares, wrote in note to clients today.

The drug, cleared for sale in 2009, treats atrial fibrillation, a rapid and irregular beating in the heart’s upper chambers affecting an estimated 2 million people in the U.S., according to the National Heart, Lung and Blood Institute.

Sanofi shares lost 60 cents, or 1.2 percent, to 51.20 euros in Paris today. The Paris-based company was the second-worst performing stock on the 18-member Bloomberg Europe Pharmaceutical Index today.

FDA Statement

Dronedarone, the chemical name for Multaq, was tied to acute liver failure, requiring a transplant, in two women of about 70 years of age, the U.S. Food and Drug Administration said in a notice on its website today. Sanofi will add new information about liver risks to the “warnings and precautions” and “adverse reactions” section of the Multaq prescribing information, said the FDA, which approved the treatment in July 2009.

Sanofi is “working closely” with the European Medicines Agency in London and other health authorities “for review of this matter,” Podvin said. “Patient safety is a priority,” he added.

Multaq sales in the U.S. reached 86 million euros ($115 million) in the first nine months of 2010, according to a statement the company published Oct. 28, lagging behind the expectations of some analysts.

‘Better in Europe’

“The product’s struggle to penetrate the U.S. market is not expected to benefit from this type of news,” Berrigaud wrote today. “The situation is apparently better in Europe.”

Multaq sales in Europe are “exceeding expectations,” Sanofi Chief Executive Officer Chris Viehbacher said during a speech at the J.P. Morgan Healthcare Conference in San Francisco this week.

Multaq was designed to be a safer alternative to amiodarone, a generic medicine with serious liver and lung risks that is only approved for life-threatening irregular beating in the heart’s lower chambers.

"Amiodarone includes a black box label citing various toxicities including severe liver toxicity," wrote Seamus Fernandez, an analyst with Leerink Swann Research, in a note to investors today. "When the dust settles, Multaq will continue to stand as a growing asset."

Fernandez said he wasn’t changing his U.S. sales estimate of $128 million for 2010 and forecast of $521 million for 2016.

Separately, Sanofi and U.S. partner Bristol-Myers Squibb Co. voluntarily recalled 64 million tablets of their Avalide blood pressure drug, said Christina Trank, a Bristol-Myers spokeswoman, in a phone interview today.