Abbott Laboratories announced the US District Court has ruled that TorPharm's generic product infringes on the Abbott patents for Depakote (divalproex sodium). Depakote has become an industry standard for the treatment of epilepsy and mania associated with bipolar disorder.

In his opinion, Judge Richard A. Posner found that Abbott has proved that TorPharm's product infringes Abbott's patents for Depakote. The US Court of Appeals had previously upheld the validity of Abbott's patents.

"We're pleased with the court's opinion. It validates the strength of our intellectual property for Depakote," said William G. Dempsey, senior vice president, pharmaceutical operations.

Abbott filed its lawsuit in October 1997 in the U.S. District Court for the Northern District of Illinois after TorPharm (Apotex) filed an Abbreviated New Drug Application for Depakote. The district court granted Abbott summary judgment on infringement and upheld the validity of Abbott's patents. TorPharm appealed the decision.

In August 2002, the U.S. Court of Appeals upheld the district court's decision as to the validity of Abbott's patents, but sent the case back to the lower court for trial on a narrow issue of infringement. The trial before Judge Posner, which began Monday, February 23, 2004, and concluded on February 27, 2004, focused on the narrow issue of whether TorPharm's proposed product is an oligomer as described in the Depakote patents.

Depakote is currently the most prescribed branded treatment for patients with mania associated with bipolar disorder and the most prescribed branded treatment for epilepsy. The compound patents at issue in the TorPharm case expire in 2008, with formulation patents on the Depakote ER formulation extending through 2018.

Depakote is indicated for the treatment of mania associated with bipolar disorder, and as monotherapy and adjunctive therapy in the treatment of patients with complex partial seizures that occur in isolation or in association with other types of seizures. Depakote is also indicated as sole and adjunctive therapy in the treatment of simple and complex seizures and adjunctively in patients with multiple seizure types that include absence seizures. Depakote is also indicated for the prevention of migraine headaches in adults.