Impax Laboratories Inc., a technology based specialty pharmaceutical company, has confirmed that the company has initiated a challenge of the patents listed in the Orange Book in connection with Gralise (gabapentin tablets, 300 mg and 600 mg).

Impax filed its Abbreviated New Drug Application (ANDA) containing a paragraph IV certification for a generic version of Gralise with the US Food & Drug Administration (FDA). Following receipt of the notice from FDA that Impax’s ANDA had been accepted for filing, Impax notified the New Drug Application (NDA) holder and patent owner of its paragraph IV certification.

On April 10 this year Depomed, Inc. filed suit for patent infringement against Impax Laboratories, Inc. in the United States District Court for the District of New Jersey. This action formally initiates the patent challenge process under the Hatch-Waxman Act.

Once the ANDA is approved by FDA, Global Pharmaceuticals, Impax’s generic division, intends to commercialize the product.

Gralise is indicated for the management of postherpetic neuralgia (PHN). According to Wolters Kluwer Health, US sales of Gralise were approximately $1.3 million for the three-month period ending February 2012.

Impax Laboratories, Inc. is a technology based specialty pharmaceutical company applying its formulation expertise and drug delivery technology to the development of controlled-release and specialty generics in addition to the development of branded products.