Plaintiffs ZS Pharma, Inc. and AstraZeneca Pharmaceuticals LP filed suit on Monday in the District of Delaware against defendants Ascent Pharmaceuticals Inc. and Hetero Drugs LTD. The complaint for patent infringement comes after the defendants filed an abbreviated new drug application (ANDA) with the Food and Drug ADminsitration (FDA seeking to produce and market generic versions of the plaintiffs’ Lokelma drug.
Lokelma is intended to treat hyperkalemia, and is a “non-absorbed zirconium silicate that preferentially captures potassium in exchange for hydrogen and sodium, thereby lowering serum potassium levels,” per the complaint.
The complaint cites 12 patents, 10 of which are titled “Microporous Zirconium Silicate for the Treatment of Hyperkalemia,” and 2 of which are titled “Extended Use Zirconium Silicate Compositions and Methods of Use Thereof.” The patents-in-suit have been listed in the FDA’s publication Approved Drug Products with Therapeutic Equivalence Evaluations.
The defendants provided the plaintiffs, according to the complaint, with a notice letter on July 18, 2022, in which they informed them of an ANDA they had filed with the FDA seeking approval to manufacture a generic version of Lokelma. The notice letter contended that the patents-in-suit are invalid, unenforceable, or will not be infringed upon by the defendant’s ANDA product.
The plaintiffs assert that according to their information, they believe that sodium zirconium cyclosilicate, which is protected under the patents-in-suit, will be present in the defendant’s ANDA product.
Similar complaints for patent infringement were also filed by the plaintiffs on Monday against Alkem Laboratories LTD, Macleods Pharmaceuticals LTD, Macleods Pharma USA, Inc., and Sandoz, Inc.
The complaint cites twelve counts of infringement. The plaintiffs are seeking favorable judgment on each count, a declaration that the manufacturing and marketing of the defendant’s ANDA product will violate the patents-in-suit, an order prohibiting the ANDA from being approved prior to the expiration of the patents-in-suit, an injunction preventing the defendant’s from manufacturing their ANDA product until after the expiration of the patents-in-suit, litigation fees, and any other relief deemed just by the Court.
The plaintiffs are represented by McCarter & English, LLP.