Sanofi-Aventis and Bristol-Myers Squibb have been stung by a German court’s decision to order immediate enforcement of marketing authorisations granted in the country for generic versions of the blockbuster bloodthinner Plavix.

Previously, the authorisations had been suspended but the German administrative court in Cologne has now backed the rights of the generic drugmaker Yes and a subsidiary of Ratiopharm to sell their copycat versions of Plavix (clopidogrel) straight away. Sanofi and B-MS said they would appeal against the two decisions.

The news follows a similar case which remains pending before the same Cologne court. At the end of May, Switzerland’s Schweizerhall announced the German approval for a version of clopidogrel, developed by its Cimex unit. It has signed up Novartis’ Sandoz unit and Ratiopharm to sell the product, though a launch was delayed as Sanofi immediately launched a lawsuit once it became aware of the bid to register a copy of Plavix in Germany with the country’s regulatory authority, the BfArM.

Sanofi said it is “convinced” that these marketing authorisations rely on data originating from the firm and its US partner so should “never have been accepted for review by any European Union regulatory agencies until after data protection expired on July 15”. The French drugmaker added that in addition to the appeal of this latest court decision and the third party objection procedure, it will “continue to pursue all available administrative and legal procedures in order to ensure the proper protection of its rights”.

There is a lot at stake here, not least a considerable amount of cash as the European market for clopidogrel has been estimated to be worth some 2 billion euros, and Germany accounts for around 18% of that total. However Sanofi has previously stated that these registrations refer to a different salt of clopidogrel – besylate – than the one found in Plavix – bisulfate – and the rival products are labelled only for a limited number of indications when compared to the Sanofi/B-MS drug.

Nevertheless, Sanofi will be hoping for a similar outcome to the US court case it won last year to stop generic competition to the blockbuster until 2011. That victory, however, was preceded by a torrid period when the North American market was flooded with Apotex’ generic version of the drug which had a huge impact on branded Plavix sales for several months.