Impax Labs confirms patent challenge to Pfizer/UCB's Toviaz

US specialty drugmaker Impax Laboratories (Nasdaq: IPXL) yesterday confirmed that it has initiated a challenge of the patents listed in the Orange Book in connection with Toviaz (fesoterodine fumarate extended-release tablets, 4mg and 8mg), an overactive bladder drug marketed by pharma behemoth Pfizer (NYSE: PFE) under a licensing agreement with Belgium’s UCB (UCB: BR).

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

On June 28, 2013, Pfizer and UCB filed suit for patent infringement against Impax in the US District Court for the District of Delaware. This action formally initiated the patent challenge process under the Hatch-Waxman Act. Once the ANDA is approved by the FDA, Global Pharmaceuticals, Impax’ generic division, intends to commercialize the product.