Arrowhead Pharmaceuticals Inc. has filed a Complaint for Declaratory Judgment in the United States District Court for the District of Delaware against Ionis Pharmaceuticals Inc. The complaint seeks to establish that Ionis's U.S. Patent No. 9,593,333 is invalid and that Arrowhead's investigational drug plozasiran, currently under FDA review, does not infringe on this patent. This legal action follows threats of litigation from Ionis regarding alleged patent infringement. Arrowhead asserts that these allegations are baseless and maintains that its development of plozasiran and its proprietary platform were accomplished independently. The company emphasizes its commitment to providing new treatment options for patients with familial chylomicronemia syndrome (FCS), a rare and severe disease. Arrowhead is confident in its position and plans to vigorously defend its claims in court.