(Adds further comments by analysts, updates share price)
By Ben Hirschler
LONDON, Aug 8 (Reuters) - Sanofi-Aventis’s (SASY.PA) experimental heart drug Multaq, which some analysts believe could be worth more than $2 billion in sales a year, is to get a priority review from the U.S. Food and Drug Administration.
Shares in the French drugmaker, the world’s third largest, rose 4 percent after it announced the decision on Friday.
The priority review period began on July 31, suggesting a likely decision by the end of January 2009, according to analysts at Dresdner Kleinwort.
The FDA grants priority review to new drugs that could present a safe and effective therapy where no satisfactory alternative exists.
Multaq appeared at one stage to have little future, after an early clinical trial showed excess mortality and the drug was rebuffed by regulators.
But new results in May from a study known as Athena came in positive and the medicine has been hailed as a promising new treatment for atrial fibrillation, a common heart arrhythmia.
“FDA has already seen the majority of this filing before, except the new Athena trial data, so it should be relatively easy for FDA to decide if the filing now meets its expectations,” Dresdner analysts said in a research note.
“Despite previous setbacks, the Athena data now looks compelling. However, given its history we are awaiting FDA approval before putting sales in our model, but we believe it has 1.5 billion euros ($2.3 billion) potential by 2015.”
Sanofi badly needs Multaq to be a success, following a series of development pipeline setbacks recently and looming competition to its two top sellers, the anticoagulant Lovenox and blood-thinning drug Plavix.
Shares in Sanofi, which fell last week on disappointing second-quarter results, were 4 percent higher at 48.40 euros by 1010 GMT.
The stock also gained from an upgrade by Royal Bank of Scotland, which lifted its recommendation to “buy” from “hold”.
Atrial fibrillation is estimated to affect about 4.5 million people in Europe and 2.5 million in the United States. Their risk of suffering a stroke increases sharply as they get older. (Reporting by Ben Hirschler; Editing by Greg Mahlich)