Barr Laboratories, Inc., subsidiary of Barr Pharmaceuticals, Inc, has initiated the challenge of the patent listed by Eli Lilly and Company in connection with Eli Lilly's Zyprexa Zydis (Olanzapine) Orally Disintegrating Tablets, 5mg, 10mg, 15mg and 20mg, the company announced here.

The patent listed in the Orange Book for Zyprexa Zydis expires on April 23, 2011. Barr's ANDA alleges that the Orange Book listed patent is invalid, unenforceable and/or would not be infringed by Barr's product.

Barr filed its ANDA containing a paragraph IV certification for a generic Zyprexa Zydis product with the FDA in August 2004, and received notification of the application's acceptance for filing in September 2004. Following receipt of the notice from the FDA, Barr notified Eli Lilly, the patent owner and NDA holder. On December 1, 2004, Eli Lilly filed suit in US District Court, Southern District of Indiana to prevent Barr from proceeding with the commercialization of its product. This action formally initiates the patent challenge process under the Hatch-Waxman Act, the release added.

Zyprexa (olanzapine) is indicated for the treatment of schizophrenia and for the short-term treatment of acute manic episodes associated with Bipolar I disorder. The product had annual sales of approximately $233 million for the twelve months ended September 2004, based on IMS sales data.