Aventis Pharmaceuticals, a division of French drug major Sanofi-Aventis, and Albany Molecular Research have filed a motion for a preliminary injunction or expedited trial in the US District Court for the District of New Jersey, seeking to prevent US group Barr Pharmaceuticals and Israel’s Teva Pharmaceutical Industries from marketing their copycat versions of Allegra (fexofenadine HCl) tablets, 30 mg, 60 mg and 180 mg.

In addition, Sanofi’s injunction aims to prohibit India’s Ranbaxy Laboratories and Amino Chemicals from manufacturing generic fexofenadine raw material for commercial use.

Barr Pharmaceuticals won FDA approval to market its generic version of Allegra earlier this year, causing Aventis Pharmaceuticals to file a lawsuit against Barr in order to prevent approval until the last of the drug’s patents expire in 2017 [[15/07/05f]].

In July last year, a US district court judge ruled that it had not infringed three of the patents covering the product [[02/07/04d]] and an additional patent was declared invalid in April this year. The court has yet to rule on five more patents covering the product and, although no trial date has been set, Barr expects the case may be ready for trial early in 2006.

Earlier this month, Barr and Teva entered into an alliance for the launch of a generic version of Allegra [[08/09/05e]], which is indicated for the relief of hayfever symptoms and the treatment of hives in adults and children aged six years and above. Allegra’s annual sales hit $1.4 billion for the twelve months to July 2005, according to IMS Health data.

However, Sanofi-Aventis has also implemented a back-up plan to help cushion the blow from generic erosion of Allegra’s sales, by signing a distribution and supply agreement with privately-held, US generics manufacturer Prasco Pharmaceuticals for its own, cheaper version of the drug [[15/09/05a]].