Shares of Switzerland’s Schweizerhall have taken a battering on the news that approval in Germany for a generic version of Sanofi-Aventis blockbuster bloodthinner Plavix has been delayed.

The delay comes as no surprise, however, as Sanofi immediately launched a lawsuit against the Swiss firm once it became aware of its bid to register a copy of Plavix (clopidogrel) in Germany with the country’s regulatory authority, the BfArM. News of the dealy sent Schweizerhall stock down 13.8% to 181 Swiss francs but the Basel-based group does not seem overly worried.

It issued a statement saying that Sanofi’s response was expected and “for the time being, this prevents the approval from being executed”, ie the green light in Germany that its Cimex unit received at the beginning of May. Novartis’ Sandoz division and Ratiopharm of Germany to sell the product have already been signed up to sell the product.

Furthermore, Schweizerhall said that in the case the approval is executed by the BfArM or by an administrative court, “which is possible anytime”, the marketing of generic clopidogrel “can start immediately”. In cooperation with their marketing partners, Schweizerhall said it has also taken legal action, including requesting accelerated court proceedings, “to achieve immediate execution of the approval”.

A court decision is expected within a few months, the firm said, noting that applications for approval in other countries, though no states were specified, are not affected by the situation in Germany. Schweizerhall concluded by saying that even if the market launch of clopidogrel is delayed, it expects sales growth of around 30% for 2008 “and a significant increase in earning power”.

Sanofi is pretty confident that it will prevail in its defence of Plavix and 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.