Sanofi-Aventis and partner Bristol-Myers Squibb have been boosted by the news that regulators in the USA have granted the companies an additional period of marketing exclusivity for their blockbuster bloodthinner Plavix.

The US Food and Drug Administration has given the green light to an additional six months of pediatric exclusivity for Plavix (clopidogrel) which means that the patent on the drug in the USA is now scheduled to expire on May 17, 2012. Plavix is a huge seller and had sales of over $9 billion in 2009, second only to Pfizer's Lipitor (atorvastatin) so the news that no generic copies can hit the market in the USA for 16 months is good news for the companies' coffers.

In October, a US judge ruled that Canada's Apotex should pay damages of $442.2 million (plus interest) for violating patents protecting Plavix. In 2006, the Toronto-based firm flooded the market with copycat versions of the drug, for a three-week period while its patent protection was still in force. Generics of Plavix are now available in Europe.

Staying with Sanofi, the FDA has given the green light to the French drugmaker  to sell its antihistamine Allegra (fexofenadine) family of products over-the-counter. The OTC versions will be available in the USA in March.

Allegra was a blockbuster and as a prescription drug is still a big earner worldwide, posting third-quarter sales of 136 million euros (-23.4%). Generics are available but Sanofi's will be the first OTC version and the market is big; over 40 million adults suffer from indoor and outdoor allergies in the USA and Allegra is the number one US-prescribed allergy treatment.

Last year, Sanofi acquired the US consumer healthcare major Chattem in a $1.90 billion deal and president of global operations, Hanspeter Spek, noted that converting prescription medicines to OTC products "is a key growth driver for Sanofi to become a diversified healthcare company, also in the USA".