Barr Laboratories Inc has been sued by Ferring B.V. and Aventis Pharmaceuticals Inc, which initiates Barr's challenge of Ferring's patent protecting DDAVP (Desmopressin Acetate) Tablets, 0.1 mg and 0.2 mg from generic competition. The Company indicated that it believes that it is the first to file an Abbreviated New Drug Application (ANDA) with the U.S. Food & Drug Administration (FDA) for DDAVP Tablets, 0.1 mg and 0.2 mg.

DDAVP Tablets are indicated as antidiuretic replacement therapy in the management of central diabetes insipidus and for the management of the temporary polyuria and polydipsia following head trauma or surgery in the pituitary region.

Barr filed an ANDA for Desmopression Acetate Tablets, 0.1 mg and 0.2 mg, with the FDA in July 2002, which certified that the four patents listed with the FDA as covering this product were invalid and/or not infringed by Barr's ANDA. Barr received notification of the application's acceptance for filing from FDA in August. Barr then formally notified Ferring, the patent holder of record, and Aventis, the New Drug Application (NDA) holder, of Barr's challenge to these patents. On December 13, 2002, Ferring and Aventis jointly filed suit on one of the four listed patents in the U.S. District Court for the Southern District of New York. The suit seeks to prevent Barr from proceeding with the commercialization of this product. This action formally initiates the patent challenge process.

Ferring manufactures DDAVP Tablets for Aventis, which markets the product in the United States. The product has annual sales of approximately $121 million for the twelve months ending October 2002.