Barr Laboratories says it will enjoy 180 days of market exclusivity when its generic version of Sanofi-Aventis’ allergy drug, Allegra-D 12 Hour (fexofenadine and pseudoephedrine), wins final US approval after the country's Food and Drug Administration agreed that a change to the firm’s application to market a copycat version of the drug would mean that no other firm would be able to sell their version of the product during Barr’s exclusivity period.

Barr had sued the FDA earlier this year, challenging its policy of awarding generic exclusivity on a patent-by-patent basis, rather than solely to the first company to file an application to sell a copycat version of a given drug [[07/02/05b]].

In July 2004, FDA tentatively approved Barr’s application to market a version if Allegra D in July last year [[05/07/04d]]. Allegra-D 12 Hour is indicated for the relief of symptoms associated with seasonal allergic rhinitis in adults and children 12 years of age and older and had annual sales of approximately $434 million for the twelve months ended February 2005, according to IMS data.