AstraZeneca sues pharmaceutical companies over generic treatment for hyperkalemia

Plaintiffs ZS Pharma, Inc. and AstraZeneca Pharmaceuticals LP complaint lodged Monday in the District of Delaware against defendants Ascent Pharmaceuticals Inc. and Hetero Drugs LTD. The patent infringement claim comes after the defendants filed an abbreviated new drug application (ANDA) with the Food and Drug Administration (FDA) seeking to produce and market generic versions of the plaintiffs’ drug Lokelma.

Lokelma is intended to treat hyperkalemia and is an “unabsorbed zirconium silicate that preferentially uptakes potassium in exchange for hydrogen and sodium, thereby lowering serum potassium levels,” according to the complaint.

The complaint cites 12 patents, 10 of which are titled “Microporous Zirconium Silicate for the Treatment of Hyperkalemia” and 2 are titled “Extended Use Zirconium Silicate Compositions and Methods of Use.” The patents at issue have been listed in the FDA publication Approved Drug Products with Therapeutic Equivalence Evaluations.

The defendants provided the plaintiffs, according to the complaint, with a notification letter on July 18, 2022, in which they informed them of an ANDA they had filed with the FDA requesting authorization to manufacture a generic version of Lokelma. The letter of opinion argued that the patents at issue are invalid, unenforceable or will not be infringed by defendant’s ANDA product.

Plaintiffs state that based on their information, they believe that sodium zirconium cyclosilicate, which is protected by the patents at issue, will be present in defendant’s ANDA product.

Similar patent infringement claims were also filed Monday by plaintiffs against Alkem Laboratories LTD, Macleods Pharmaceuticals LTD, Macleods Pharma USA, Inc. and Sandoz, Inc.

The complaint cites twelve counts of offence. Plaintiffs seek a favorable judgment on each count, a statement that the manufacture and marketing of Defendant’s ANDA product will infringe the patents at issue, an order barring approval of ANDA prior to the expiration of the patents in case, an injunction restraining the defendants from manufacturing their ANDA product until the expiration of the patents at issue, legal costs and any other relief deemed just by the Court.

The plaintiffs are represented by McCarter & English, LLP.