Impax sued for patent infringement over generic Welchol

HAYWARD, Calif. A generic drug maker confirmed a patent challenge for its version of a branded cholesterol drug that recently was submitted to the Food and Drug Administration for approval.

Impax said Daiichi Sankyo and Genzyme are seeking to block Impax's generic version of Welchol (colesevelam HCl) for oral suspension, in 3.75 g/packet and 1.875 g/packet strengths. The two drug makers filed suit for patent infringement against Impax in the U.S. District Court for the District of Delaware after being notified that the FDA accepted Impax's ANDA for the drug.

U.S. sales of Welchol for oral suspension were approximately $39 million for the 12-month period ended in September, according to Wolters Kluwer Health.