Impax Laboratories Inc confirmed that it has initiated a challenge of the patents listed by Genzyme Corporation in connection with its Renvela (sevelamer carbonate) 800 mg tablets.

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

On April 3, 2009, Genzyme filed suit for patent infringement against Impax in the United States District Court for the District of Maryland. 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, will commercialize the products.

Renvela is indicated for the control of serum phosphorus in patients with chronic kidney disease on dialysis. According to Wolters Kluwer Health, US sales of Renvela 800 mg tablets were approximately $40 million for the twelve months ended February 2009.

Impax Labs 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.