Barr Pharmaceuticals confirms patent challenge of Namenda tablets

Barr Pharmaceuticals, Inc. has confirmed that its subsidiary, Barr Laboratories, Inc., has initiated a challenge of the patent listed by Forest Laboratories, Inc. in connection with its Namenda (memantine hydrochloride) tablets, 5mg and 10mg.

Barr filed its Abbreviated New Drug Application (ANDA) containing a paragraph IV certification for a generic Namenda product with the U.S. Food & Drug Administration (FDA) on October 16, 2007, the first date the FDA could accept an ANDA with a paragraph IV certification for this product. Following receipt of the notice from the FDA that Barr's ANDA had been accepted for filing, Barr notified the New Drug Application (NDA) and patent holder.

On January 10, 2008, Forest Laboratories Holdings, Ltd., Forest Laboratories, Inc., Merz Pharma GmbH & Co. KgaA, and Merz Pharmaceuticals GmbH filed suit in the U.S. District Court for the District of Delaware to prevent Barr from proceeding with the commercialization of its product. This action formally initiates the patent challenge process under the Hatch-Waxman Act.

Namenda (memantine hydrochloride) is indicated for the treatment of moderate to severe dementia of the Alzheimer's type. The product had sales of approximately $824 million in the U.S., based on IMS sales data ending October 2007.