Case Explained: MELINTA THERAPEUTICS, LLC v. NEXUS PHARMACEUTICALS, INC

Court: United States Court of Appeals for the Federal Circuit Filed: 2026-06-05 The federal-circuit affirmed the district court’s judgment that Nexus Pharmaceuticals infringed Melinta Therapeutics’ U.S. Patent No. 9,084,802 and rejected Nexus’s arguments that the patent was invalid. The court applied de novo review to claim construction and clear error review to factual findings regarding written description under 35 U.S.C. § 112. Regarding claim construction, the court upheld the district court’s interpretation of “composition” and “administering,” concluding that a person of ordinary skill in the art would understand that a diluent must be added to the concentrated solution prior to intravenous administration, despite the claims using the closed term “consists of.” On the issue of written description, the court held that the district court did not clearly err in finding the patent valid because the specification supported the claim limitation requiring reduced hemolysis relative to a composition without magnesium by comparing the claimed formulation to prior art formulations lacking any metal cations, rather than comparing it to formulations containing other cations like calcium. The court declined to address the validity of the second patent at issue (U.S. Patent No. 9,278,105), noting that because both patents share the same expiration date and infringement was established for the first, a ruling on the second was unnecessary. As a practical consequence, the permanent injunction preventing Nexus from manufacturing, using, offering for sale, or selling its generic ANDA product remains in effect until the expiration of the ‘802 patent. Do It For The Case Law is a news reporting service. Nothing in this episode constitutes legal advice.