Barr Pharmaceuticals is challenging Aventis Pharmaceuticals' patents for nasal allergy spray Nasacort AQ, Barr has announced.

Barr filed its abbreviated new drug application in December 2005 challenging Aventis' patents on Nasacort AQ (triamcinolone acetonide). Barr filed its application with a Paragraph IV certification, which means the applicant believes the patent is invalid or will not be infringed upon by the generic product.

Aventis, a subsidiary of French drugmaker sanofi-aventis, filed a patent infringement lawsuit against Barr on May 2 in the U.S. District Court for the District of Delaware. Barr co-developed its generic Nasacort AQ product with drugmaker Perrigo and said Perrigo will share in the costs and potential benefits of trying to launch the product.

Nasacort AQ treats nasal symptoms of seasonal and perennial allergic rhinitis in adults and children ages 6 and older. The drug had annual sales of approximately $346 million for the 12-month period ending in March.