Shares in Sanofi-Aventis have declined this morning after a Swiss generics firm said that it is close to getting approval for a copycat version of the French drugmaker’s anti-platelet agent blockbuster Plavix.

Basel-based Schweizerhall is claiming that a version of Plavix (clopidogrel) developed by its Cimex unit, could be available very soon, saying that the decentralised approval procedure for its product has been successfully completed. Schweizerhall chairman Luzi von Bidder stated that “we expect shortly a positive ruling from the German authorisation agency for medicines and we plan to launch clopidogrel throughout the European Union” with partners.

This news comes as something of a surprise given that Sanofi believes it has patent protection in Europe for Plavix until 2013 at least and it recently emerged victorious in a long-running US court case which ensuring protection for the product there until November 2011.

Nevertheless, Schweizerhall’s enthusiasm does not appear to be dimmed by this and the firm says that a first licence agreement with “a major generics company” was already concluded and the signing of a contract with another generics provider is imminent. “We expect first sales already in the current quarter,” said Mr von Bidder, adding that besides Germany, clopidogrel could also obtain marketing authorisation in Luxembourg within the second quarter of 2008.

Applications for approval in additional countries are being prepared, Schweizerhall said, noting that the European market for clopidogrel is currently about 2 billion euros, of which Germany accounts for 600 million francs.

Nobody at Sanofi was available for comment as PharmaTimes World News was going online but investors are already starting to worry as the shares at 10.20am were down 4.3% at 48.30 euros.