Sanofi-Aventis won approval to sell heart treatment Multaq in the United States, a move that should help the French drugmaker partly recoup a future sales drop as generics to several key drugs appear.

Analysts see Multaq, put forward as a blockbuster, as one of the growth drivers Sanofi has up its sleeve to drag it through the years when patents expire on multi-billion euro drugs like cancer treatment Taxotere and blood thinner Plavix.

The Food and Drug Administration cleared (FDA) Multaq twice-daily 400 mg tablets to reduce the risk of cardiovascular hospitalisation in patients with atrial fibrillation or atrial flutter, Sanofi said on Thursday. Doctors may not prescribe Multaq to patients with severe heart failure.

"This is an expected positive, which breaks Sanofi's eight-year streak of not getting an important non-vaccines drug onto the market," UBS analyst Gbola Amusa said, forecasting sales of as much as 1.4 billion euros by 2014, 2015.

Sanofi plans to begin marketing Multaq, generically known as dronedarone, in the United States this summer, offering an alternative to the generic amiodarone which can, however, cause damage to the lungs or thyroid gland.

Diabetes drug Lantus was Sanofi's last main launch in 2001. Since then it has turned into a top drug -- making 2.45 billion euros in sales in 2008 -- but its image was blemished last week following inconclusive studies that suggested a possible cancer risk.

Sanofi stood by Lantus, saying it was safe, while European and US healthcare regulators doubted a link between Lantus and cancer, saying patients should not stop using the drug.

The approval of Multaq, which awaits clearance by the European regulator, helped push up Sanofi's recently battered shares. They added 0.2 percent to 43.31 euros by 1204 GMT, beating a 0.5 percent drop in the DJ healthcare index.

Amusa cautioned that a risk management programme to monitor the proper use of Multaq, would initially limit the use of Multaq. "It's a drug that will come into the market slowly."    

Sanofi said it would help doctors identify the appropriate patients to ensure the safe use of Multaq. Patients will be given a medication guide while Sanofi will continue to scrutinise the drug once it is marketed.

Atrial fibrillation is an abnormal heart rhythm in which the upper chambers of the heart beat in an uncoordinated manner which can cause palpitations, shortness of breath and fatigue and raise the risk of more serious heart problems.

More and more people were suffering from the disease due to an increasingly ageing population, Sanofi said, adding it affects about 2.5 million people in the United States and 4.5 million in the European Union.

"We are pleased that the FDA has granted approval of Multaq for patients in a therapeutic area that has seen few new treatment options in the last twenty years," Sanof's head of Research and Development, Marc Cluzel, said in a statement.

Later on Thursday, Sanofi will host a seminar on emerging markets. Sanofi aims to derive part of its revenue stream from fast-growing countries in Latin America and Asia, where large parts of the population do not have regular access to medicines.-Reuters